Audio Instruction – Aaron J. Trumm

Tune That Room

November 4, 2019 by Aaron

aaron trumm, acoustic treatment, acoustics, budget acoustic treatment, home recording, recording, recording magazine, soundproofing

The art of DIY Accoustic Treatment

This article first appeared Recording Magazine. I reprint it here with permission, and I encourage you to subscribe to that publication, as they are a stand up bunch of folk!

Ask an amateur recordist where they spent the most in their studio, and the answer is likely a piece of gear. Ask any PROFESSIONAL audio engineer what the most important thing in the studio is, and they’ll say acoustics.

Anyone who’s mixed in a boxy room knows how hard it can be to hear what’s going on, and plenty have experienced the sadness of a poorly translated mix that’s boomy, tinny or muddy in other places. Or, you may have noticed the terror of vocals recorded in an empty room – that hollow, boxy sound that should be reserved for bad indie movies and tele-conferences.

The reason for these problems is sound reflecting and interacting, creating nodes (where a given frequency is cancelled by its out-of-phase reflection), peaks (the opposite condition), comb filtering, ring, flutter and plain ‘ol reverb. The size and dimensions of a room determine where and at what frequencies problems occur, but any normal room has 3 pairs of parallel surfaces, which is the worst possible situation for acoustic interaction.

These facts are becoming more apparent to musicians, and there are fewer square boxes with $10,000 DAWs and no treatment. There are still plenty of expensive studios built to spec, but what about bedroom studios, renters and low budget recordists? Can they build a trustworthy space they can use to get great results? Yes, and it’s not that hard.

Before We Begin

First off, let’s distinguish “acoustic treatment” from “sound proofing”. “Sound proofing” means ISOLATION, which is different than treatment. Isolation means making a room that lets no sound in or out. Doing this effectively takes structural work (which renters can’t do), and is a very different physical phenomenon than treatment. Treatment is making a room sound and function better as an acoustic space, by taming or eliminating reflections INSIDE the room that cause problems. We’re talking about treatment, not isolation, and the great thing is we can do all of our acoustic treatment ourselves.

We also won’t talk about measurement. While measuring a room’s acoustic response with testing equipment and by calculating modes and resonances using room dimensions can be useful in some situations, generally the solutions are always the same. So measurement is outside scope of this article.

Low Frequencies First

Figure 1 – The author’s incredibly terrible early attempt at treatment

Often home recordists just tack a lot of acoustic foam or egg shell mattress on every wall (figure 1). This can be ugly, and it doesn’t work very well. In a room like that, you might clap your hands, hear no reflections and think you’re done. The problem is clapping can’t tell you what’s happening with LOW FREQUENCIES. When you tack up acoustic foam, you’re only dealing with high frequencies. To illustrate, consider this chart:

Material	125HZ	250HZ	500HZ	1000HZ	2000HZ	4000HZ
OC 703	0.17	0.86	1.14	1.07	1.02	0.98
OC 705-FRK	0.60	0.50	0.63	0.82	0.45	0.34
Sculpted Acoustic Foam	0.11	0.30	0.91	1.05	0.99	1.00

Absorption coefficients – 2 inch thick material applied directly to a wall.

Absorption coefficient is a number that represents how much sound is absorbed by a given material at a given frequency. In this small chart you can see that at 2 inches thick, all these materials have pretty pitiful absorption below 250HZ. You can also see that Owens Corning 703 and 705 rigid fiberglass (or equivalent) does a better job than typical acoustic foam.

There’s a better approach, and that’s to build from the ground up, frequency wise. Start your design with LOW frequencies. Low frequencies (below about 200hz) behave differently than higher frequencies, so the solutions are different, and it’s low frequency reflections that cause nightmares like boomy rooms, weak low end response, or untranslatable mixes.

There are a couple of common misconceptions to address here. One is that if you listen at a low volume with near field monitors, the room isn’t a factor. Actually, sound is always reflecting and interacting, and those reflections must be dealt with. Another is that low frequencies don’t have time to “develop” in a small room and thus aren’t a problem. In reality, low frequencies are always present and reflecting off walls, even in a small room.

So what to do? For all frequencies, there are two options: absorb or diffuse. It’s mostly impractical to diffuse low frequencies, so we need to absorb them. Since that’s not a matter of throwing up some foam (unless it’s 10 inches thick or spaced 16 inches from the wall), we need other solutions. First, start with the corners. Low frequency build up occurs in corners, so the first and most obvious place to start absorbing is vertical corners. There are several ways to do this, but they all boil down to spanning and/or filling the corner.

An easy, relatively inexpensive and effective way to do this is by spanning a corner with Owens Corning 705-FRK rigid fiberglass (figure 2). These come in 4’ by 2’ foot panels, so in a typical room, it takes two to go from floor to ceiling. 705-FRK (FRK is a paper backing with a foil face) is dense – 6lbs per square foot – and isn’t as good for high frequency absorption as 703 (3lb density), but spanning a corner with it is great for low frequency absorption. A 4 inch thick panel is best here, but 2 inches works too. Optionally, fill the space behind the panel with fluffy fiberglass. Face the backing into the room to reflect high frequencies if you don’t want the room too “dead”, which will improve low frequency absorption a little.

Figure 3 – Fiberglass triangles for a superchunk bass trap

Another method, the “superchunk”, is more costly, but it’s even more effective and easier to make pretty. A superchunk is made using OC 703. Cut the panels into triangles (figure 3) and stack the triangles into the corner. Then cover the entire structure with some kind of acoustically transparent material (muslin, burlap, anything breathable) to make it attractive and keep the fiberglass contained (figure 4).

A warning: Fiberglass, while not toxic, is itchy and breaks off into airborne pieces. Wear sleeves, gloves and a mask when working with it.

There are also commercial “superchunk” products. Auralex makes a “bass trap” which is a corner piece of acoustic foam and RealTraps make a corner trap which is exactly a superchunk module with the addition of a “limp membrane” face, which increases low frequency effectiveness, just like the FRK.

If your budget’s REALLY tight, and you’re willing to compromise on effectiveness, you can fill a corner with a lot of things. I once filled a corner with old clothes and contained it using pegboard (figure 5). This isn’t as effective as a superchunk or 705, but it’s certainly better than nothing. You could also stack fluffy fiberglass bails in corners without even removing the packaging. It’s ugly, but effective if you have room.

Figure 5 – An odd bass trap in the author’s former studio

Vertical corners aren’t the only corners in a room. There are also the floor/wall corners and wall/ceiling corners. In most rooms, you should absorb as much low end as you can afford to, and you really can’t do too much, so consider doing something there (figure 6).

Figure 6 – A drum studio with corner traps and ceiling traps

Corners are a great start, but probably not enough. Especially with LF absorption, effectiveness is about treating a high percentage of the surface area in the room. As mentioned above, it’s effective to put up very thick material or space it out from the wall a good ways (think 4 inches with a 16 inch gap). That takes a lot of space and still isn’t very effective below about 125HZ, but there are other solutions.

Figure 7 – An untreated beam ceiling is a great opportunity

In an unfinished space with support beams (figure 7), you can put a couple nails in and rest a piece of 705 on them, creating a ceiling trap. You should probably cover that with fabric (figure 8).

Figure 8 – Beamed ceiling in process of treatment

Optionally, fill the space above with fluffy fiberglass. For a no budget alternative, foam and old clothes might work (figure 9).

Figure 9 – Poor man’s beamed ceiling treatment

Panel Traps

All of the solutions we’ve discussed so far are called “velocity absorbers”, because speed drives sound into the material, and that’s dampened when waves hit it. Panel Traps work on a different principle and are called “pressure absorbers”. Placed at room boundaries, they take less space and can be effective to lower frequencies (figure 10).

A panel trap is a little more complex to build, but it’s decently cheap and easy. The main difference is that a panel trap is a sealed box with a thin plywood face and fiberglass inside (figure 11). They’re usually sealed to the wall, but can be made to stand alone, as long they’re located at a boundary. I’ve built several, once with futon slats I found in a dumpster! While panel traps take a little more effort to make, they’re an awesome way to increase low frequency absorption with little space, and since they’re reflective at high frequencies, won’t make a room too dead sounding. Plus, you can paint on them and make them pretty.

There’s a great tutorial on how to build panel traps by acoustician Ethan Winer. I highly recommend referring to it: http://ethanwiner.com/basstrap.html

The Highs

Once you’ve dealt with the lows, it’s time to deal with highs and mids, and the physics here are much easier. High frequencies can be thought of like a ray of light – they bounce off of reflective surfaces at the same angle they come from. Any surface that shouldn’t reflect, you can absorb or diffuse.

Diffusors spread reflections in an even manner. They’re a great way to even things out while preserving liveliness. You can build several types of diffusors or buy them, sometimes for a decent price (figure 12,13). If you’ve got no budget, you can create some semblance of diffusion with book cases and other random items. While an acoustician would say this isn’t true diffusion, in practice it works ok if things are various sizes.

Real diffusion is a great way to even out the sound of a room and keep it live, but it doesn’t work in small spaces. A typical bedroom is too small for effective diffusion, so strategic absorption is often the best bet. For that reason, that’s all we’ll say about diffusion.

High frequency absorption is the easiest to deal with. 2 inch OC 703 absorbs beautifully down to about 400HZ, and there’s a trick you can use to increase absorption even more. Mount panels away from the wall. The ideal distance is the same as the thickness of the material, so mounting 2 inch panels 2 inches away from the wall or ceiling is perfect (figure 14).

Figure 14 – Absorbing panel spaced from surface

Where to mount them depends on the room and your needs, but if you’re treating a mix/control room, you should start with a “reflection free zone” (RFZ) around the main listening area. You can see where to treat with a mirror, or just sit in your chair and look left, right up and down. These are parallel surfaces you should treat. You should maintain left-right symmetry, and you should treat that area of the ceiling, but leave the floor alone. If there’s carpet you’ve got some high frequency absorption already, but that’s not ideal for various reasons, so leave the floor as is if it’s wood or another hard material. You can always throw a rug down for extra deadening.

There are a few options for materials here, and if you have to settle for egg crate foam, do it. If you have to nail a bunch of blankets to the wall, go for it. Ideally, make panels using OC 703, and cover them with an attractive but breathable fabric. Spacing of these panels from the wall can be as simple as four wood blocks from a scrap heap (figure 15).

Figure 15 – Spacer blocks salvaged from scrap heap

If you’re treating another kind of room – say a recording room or home theater – then you probably want an even sound everywhere. If you space high frequency absorbers around, alternating with either panel traps or plain wall, you’ll start to create a kind of “pseudo diffusion”. If you have no budget, don’t be afraid to nail blankets to walls, just remember: the thicker the better.

Creating a booth is pretty easy if you have a closet. You can pack the closet with clothes, hang blankets from the walls, or use a more professional approach and install fiberglass panels. In a booth, you want the deadest sound possible, and that’s about all there is to it.

I keep mentioning rigid fiberglass because it’s the best sound absorbing material and it’s cheaper than acoustic foam products, but if you can’t spend money, there are plenty of alternatives. You can even go around your neighborhood and ask if anyone has anything “soft” they need to get rid of! This can work great – but it may not lead to the prettiest space.

Modularity And Aesthetic

We’re talking about DIY acoustic treatment here, rather than permanent professional studio installations. So you may have to move your studio when you move to a new space. Or if your “studio” is a shared space, you might have to try for a pleasing look. Even if it’s not, you may tire of working in a space that looks like the inside of an egg-carton or a construction site. There are plenty of ways to treat a room and make it ugly, and plenty of ways to permanently install treatment and effectively ruin the room once you leave, but it’s just as easy and not necessarily that costly to do things in a way that doesn’t leave a mark, is easy to move, and is nice to look at.

Figure 16 – High frequency absorbors designed to hang like paintings

In my current space, everything is built to move. All of my high frequency absorbers are small painting size boxes with pretty frames and colorful fabric faces (figure 16). They hang just like any picture (figure 17).

Figure 17 – HF absorbors hanging like paintings.

Ceiling treatments are lightweight and hang from tiny hooks (figure 18).

Figure 18 – HF ceiling panels in author’s studio

My “superchunk” is really 4 small modules that I can take out and move (figure 19), and my panel traps are standalone boxes set on the floor or hung with picture wire, with decoupage designs by an artist friend (figure 20).

Figure 19 – Modular superchunk corner trap.

Figure 20 – Author’s panel trap with art by an artist friend

The room doesn’t necessarily look normal (figure 21), but it’s certainly not crazy making like my first attempts 20 years ago. In fact a lot of people mistake my HF panels for art.

Figure 21 – The author’s one room studio space.

Just Do It

Nothing we’ve talked about here is much different than what would be done with a big budget, except structural work. Other than that, acoustic treatment on a budget can be as good as any expensive installation. You can hire contractors and consultants to design and build, or you can follow some pretty straightforward principles and do it yourself. It’s one place where you really needn’t compromise, and it’s the one place where you really shouldn’t. So have fun and get your room tuned up!

Studio Deliverables

August 5, 2019 by Aaron

aaron j. trumm, aaron trumm, audio recording, deliverables, recording, recording magazine, recording studio

Come away from the studio with more for your money

This article first appeared Recording Magazine. I reprint it here with permission, and I encourage you to subscribe to that publication, as they are a stand up bunch of folk!

When people talk about making money with music, they talk about two sources: Gigging and CD/Download sales. If you have a great live act and you’re very popular, gig money can be significant, but it’s no secret the sales side is hardly ever big, and much has been made of its imminent demise. That part’s debatable, but it’s a fact that record sales have never been the main revenue stream for major labels or the companies that own them. Not to mention, few of us are rock stars, and believe it or not, some people don’t want to be! In short, the rock star business model is non-viable, and even labels know this. Thankfully, there are many other ways to generate revenue from music.

Alternative music income is talked about a lot, but what can musicians DO to maximize income? In this piece, I’ll focus on the first part, the part without which nothing else can happen: the product. Specifically, what do you need to leave the studio with in order to maximize earning potential? Or, what are the studio’s “deliverables”?

When I think about all the hopeful bands that have come and gone in studios I worked at, who went away with only stereo mixes, I cringe. They’d leave the studio with a brand new set of 10 songs, mixed to perfection, hoping to make it rich. Not only is that not enough, that’s the ONLY part of the recording that probably isn’t valuable financially!

So if beautiful amazing songs sung with passion and purpose, mixed by the best mixer in town aren’t what you want to leave the studio with, what is? First off, of course you need those main mixes. You might refer to these as album or straight mixes. These are the songs that go on your CD, go out to iTunes, go your website and go on the radio…right? Not quite.

Radio mixes

Your album mixes aren’t necessarily the ones that go on the radio. So your first new deliverable is radio mixes. Obviously, you need mixes with no cuss words. With a DAW, it’s no problem to do a “save as” and save a radio mix, where the engineer cuts words from the vocal, or reverses them, or does some other magic to “censor” your song. Even better, write a version of the song with no cussing, and when you’re overdubbing vocals, record the “clean” version with the same mic setup, same vocal style, etc. This is the method Dr. Dre and Snoop Dogg used to make palatable versions of otherwise un-airable songs, which also didn’t sound edited or censored. The benefit was multiplied when anyone who bought the album heard a new, harder-core version of the lyrics.

Lyrics are not the only thing at play though. While not universally true if you include avant-garde shows, you might as well tell yourself that no one will ever air a song over 3 minutes. That doesn’t mean the 4:20 album version needs to be cut. That’s another opportunity to give a fan something more. But whenever possible, do yourself a favor: do another “save as”, and edit a version with less intro, a shorter guitar solo, whatever it takes to get in the 3:00-3:10 sweet spot. Just like with lyrics, it may help to perform this ahead of time.

Next up…

Alternative mixes

One of the biggest possible revenue streams requiring the least amount of fame, as well as one of the best ways to develop great industry connection, is licensing. This is another hot topic lately, and for good reason, but all you have to do is watch TV for an hour, and you will realize that however clean you made that previously raunchy lyric, you probably won’t hear it behind a movie or TV scene. You may want to write instrumentals, but first do another “save as” and print your mix without vocals. You can do one with the backing vocals in, but make sure you’ve got one that has zero words whatsoever. Great lyricists may resist this, but a song WITHOUT words is usually more valuable to a video production. Why? Two reasons: one, movies and TV shows have dialog, and lyrics clash; and two, your lyrics tell a story, and that story probably doesn’t fit. Without words, though, your track might go great with the story.

As an added bonus, if you’re a vocalist with no band, you can use instrumentals as performance mixes for live shows. If you’re very detailed, you might print an instrumental with less reverb on the instruments, for venues where the room is already pretty live. Don’t forget that DJs like to have acapella versions they can pair with alternative beats, so print a vocal only mix.

That’s not the end of alternative mixes. Remember when you edited the length of your radio mixes? You’ll want to do that again for licensing libraries. Start with 30, 60 and 90 second versions. While you’re at that, you probably want some 30-45 second promo clips for your website. Make both vocal and non-vocal versions of these.

That’s not all. Let’s say a big movie needs a song about being crazy, and your song is actually CALLED “I’m Crazy”? It’s perfect, but it has a horn solo, and the movie wants a bridge, no solo. No problem, if you’ve done another edit or performed a version that has a bridge and no solo.

You may also want an acoustic version, or, my favorite, a bunch of ready-made breakdowns. Do just the drums and bass, just the drums, a drumless mix…use your imagination. Remember to pay attention when you’re editing breakdowns to keep things sensical. A fade in may have worked in the full mix but not now. Maybe there’s a four bar drum solo which will turn into inexplicable silence in a drumless mix. Track wisely in anticipation of this. If your drums bleed into your vocals, you can’t use that track for your drum-free mix. You might have to TRACK multiple versions to have multiple versions available later. (For more flexibility and responsiveness, see the sidebar where I talk about separations.)

When it comes to alternative mixes and breakdowns, the point is to leave the studio with a lot of material in hand, so you can respond to industry needs quickly. You don’t want to be stuck waiting for studio time to reprint an instrumental if you’re asked for it. Not only is that inefficient, it’s not as cost effective as leaving the session with what you need.

The point is to maximize the amount of valuable material that comes out of what you were doing anyway. To that end, there are a couple of other things to consider; things you may not need to spend costly studio time on, but could prove valuable.

Lead sheets, tabs and sheet music

It took me a long time to see any value in having written music as part of the package of material that goes with a release, but they can be crucial. If you’re a solo artist who needs musicians for live settings, lead sheets or sheet music are critical for efficient learning. Tabs and sheet music are also publishable, giving you a possible new revenue stream, and if you’re submitting demos to publishing companies, they often require lead sheets and lyric sheets. It’s very valuable to have proper musical documentation. For natural improvisers, this can be tedious, but I highly recommend putting in the effort.

Video and photos

Behind the scenes footage or footage of performances in the studio may not always be directly monetizable, but it’s well known by now that YouTube is a critical part of a musician’s promotional arsenal, and there is SOME possibility of revenue from YouTube advertising. Not to mention that pictures and video clips are a huge value-add for websites and other promotional material. Heck, you might as well shoot your next 8×10 glossy with a cool mix desk background while you wait for the engineer to set up mics.

Surround

I’d be remiss not to mention surround sound. It would be false to claim that surround mixes are a necessary part of a production’s deliverables, because for the most part they’re not asked for, and there’s virtually no consumer market, but if you happen to be in a studio that has the capability, doing another “save as” and creating a 5.1 version of a mix could be a cool addition to what you offer. I highly recommend starting with the finished stereo mix and enhancing from there (although one could argue other methods), since you want to create the same basic musical experience. Especially if you’re going after movies, 5.1 versions could be valuable. But do consider your potential cost/benefit ratio before doing surround.

Documentation and project files

Last but not least, never leave the studio without copies of ALL your project files, raw tracks and any notes or documentation. Copy the folder the DAW project is in, and make notes of the software version, hardware, and especially the plugins used. You need this material in your hands, not just stored at the studio. You never know if the studio will lose your stuff, or if you may be halfway around the world needing to fix something at the last minute. Unless it’s owned by a label (in which case this advice is for them), you put yourself in a much better place by keeping your material on hand.

Hopefully now you can see how much more value you can pull from your studio time. If you’re efficient, it won’t cost much more to get everything you need. Then your living needn’t be tied to your fame, and that, in my humble opinion, is a huge relief! Happy monetizing!

SIDEBAR: Separations

Since I work in various DAWs, I’m a huge fan of separations. I leave the studio with full separations of a mix, so I can call it up and deliver breakdowns or alternate edits at will in any software, without going to the studio. I also sometimes send full separations to the mastering engineer, so he has better control.

Full separations means every track is separated; kick, snare, guitar, vocal, etc. These tracks can import into a DAW, set at zero with no processing, and the mix sounds exactly like the finished stereo mix. It’s easy to mute a few tracks and create a breakdown, or edit an new version. You can also take the separations to a totally different studio to do surround versions later.

With separations, even if you don’t have the same rig as the studio, you can do breakdowns and re-edits to your heart’s content without having to go back. This is a great way to be able to quickly deliver what’s needed to a client without having to own a full-fledged studio yourself.

Exporting full separations, however, can be a long process. Some software (and tape) can only mix-down in real-time, which means you have to mute all but one track and mix-down over and over to achieve full separations. 24 tracks equals 24 passes, which for a 3 minute song is 72 minutes – over an hour of studio time. Also, if you’ve got processing like EQ or compression on the final stereo buss, running just one track through that processing will hit differently than the whole mix, so your final set of separations may not be what you thought. Some software like Sonar allow you to export all busses at once, so strategic buss assignment can speed things up, but you still need to be careful about overall processing.

So, proceed with caution, but consider the value of getting separations, or the alternative: get your own copy of the software and plugins in your favorite studio, so you can call up projects as is and deliver new edits. You don’t need the whole studio to do this, only the same software.

Caging The Beast

July 8, 2019 by Aaron

aaron j. trumm, piano, piano micing, piano miking, recording magazine, recording piano

How to mic pianos

First appeared in the May 2016 Recording Magazine, reprinted by permission.

I have a lyric, “88 ebony and ivory blisses”. Many people feel that way about the piano – until they have to record it. The piano is big, complex, has a frequency range as large as human hearing. Plus, there are hundreds of different kinds. It’s a beast, and caging it is said to be the most frustrating thing in recording, but I think of it differently. For me, it’s the instrument with the most possibility. But “possibility” means variables, and that can be overwhelming, so I’ll try to get you started here.

I won’t go into the history or construction of a piano; you can look at previous articles by Michael Schulze and Nathan Rosenberg for that. I’ll just dive into miking it, and try to cover as many bases as possible. I’ll focus mainly on grand pianos, but I’ll give lip service to uprights.

The way I think about miking the piano is to first visualize the instrument and the room it’s in. I picture all the places a mic could go, and think about what that will sound like. I might even have someone play while I put my head in those spots.

Next, I think about how the piano can be manipulated. There are four basic states: open, half stick, closed lid, and lid removed. Where the instrument is in the room, the room itself, and playing style are also factors I lump into this category. I also put “problems” in this category: noisy pedals, overly bejeweled player, clicky fingernails, rattling keys, creaky benches, tuning issues, etc.

Next is context. Is it a concert or a recording? Is it a solo or group piece? Are there other instruments playing in the room? Classical? Pop? Rock? Where on the piano will we be playing? All of these factors influence your choices in miking up the beast.

Last, I think about the mic, pickup pattern and technique. Dynamics are rarely used in piano miking because the heavy diaphragm lacks the ability to capture high end nuance, but it’s not unheard of. Both large and small diaphragm condensers and ribbons are common, usually with an omni or cardioid pattern. Techniques boil down to spaced or coincident, and there are several flavors of each.

To review the overview, we’ve got: Placement, Instrument, Context, Mic(s).

I’ll center around placement, and consider other variables around that.

Room Micing

Many engineers would disagree with this, but I think there are no wrong places to mic a piano. It depends on what you want to hear. For example, if you want a muddy sound, you could go behind the lid, but usually the accepted place to mic any instrument is in front of where it fires. With a grand piano, that’s in front of the open lid, which is a large area. As with anything, the closer the mics are, the less room sound you get. This is a place to consider context. In classical recording, it’s typical to place mics in the room. You will notice the piano sounds even and live this way. How far back depends on the room, but try 2 or 3 feet back for a relatively close sound in a decent room, and go back from there. Try head high when you’re closer, or draw an imaginary line along the angle of the lid. Place the mics around where that would line would be – higher if farther away. This can help with capturing high frequencies reflecting from the lid.

With the lid at half-stick, high frequencies reflect more downward than into the room. So you won’t get as much high frequency brilliance with a half closed lid and room mics – a duller sound. Closing the lid and room miking really won’t work, unless you want major high frequency attenuation and a muddy sound. In the classical context, we usually leave the lid fully open.

As far as mic choice, small diaphragm condensers work great. Large diaphragm condensers are awesome too, but small diaphragms have a better off axis response, which is nicer for capturing reflections. You can do a cardioid pattern here, but if the room is nice, an omni pattern might be better. Even in omni, point the mic at the source (downward toward the strings), because there will always be SOME off-axis coloration.

You can choose between a single mic, a spaced pair (Figure 1), or a coincident pair like an X-Y (Figure 2). A spaced pair is straight forward but comes with two potential problems: phase and “hole in the middle”.

If they’re spaced too wide (Figure 3), you could get a feeling of having a hole in the middle of the stereo field. You can bring them a little closer, or you can try adding a third in the middle.

The other potential issue is phase. As your spaced pair is summed to mono (which still happens quite a bit in broadcasts), you could find a major change in tonality based on complex phase interactions. Careful placement and checking in mono can help, or you can change your technique to an X-Y placement. This will create a more natural stereo image, eliminate any “hole in the middle” issues, and (mosty) take care of phase and mono compatibility issues. That makes X-Y configuration seem superior, but I myself am more likely to use a spaced pair.

In front of the lid or way out in the room is not the only room miking option. You can also try a behind the player placement. An X-Y slightly above the player’s head, pointing down toward the strings (not the keys) is good, and I like to put a spaced pair 2 or so feet behind the player, 3-4 feet apart (Figure 4).

Figure 4 – Behind The Player Spaced Pair

There’s no reason not to try various locations in the room or multiple mics simultaneously. You’re under no obligation to use all the tracks in your mix. One of my recent sessions was miked with 4 spaced pairs of small diaphragm condensers. One was 2 feet apart at the edge of the piano, another was 4 feet apart about 4 feet back, another was about 10 feet back, 8 feet apart, and another was a pair behind the player. I varied my use of the tracks in the mix, but I found that the farthest room mics added nothing, because the room was fairly dead. Don’t be afraid to experiment, and throw away what doesn’t work.

Close Miking

Close miking a piano is more typical of pop and rock music, and is, to me, more complex and interesting. There are a million ways you could achieve something cool with close miking.

Any placement starting at the edge of piano and moving in toward the strings we’ll call close miking. I like a spaced or X-Y pair right at the edge of the case, where it curves, about two feet above the edge. Another set up I like is a spaced pair of 414’s a little deeper into the piano, but still a good 2 or 3 feet above the strings. As you move toward the strings, you’ll find more distinction, ie: certain strings will be emphasized more. This isn’t always good, so you want to play with placement and think about where the song is mostly played.

Another technique is to use an X-Y pair in the middle of the piano, using cardioid patterns. The directionality of the cardioid pickup in this situation can pick out the high and low strings.

Recently I put an omni 414 deep into the piano, about 6 inches above the low strings and 3 inches behind the dampers, to emphasize a line that was played only on the lowest octave. This track I centered in mono, but there were 3 other tracks to mix with: a 414 a foot above the highest strings, and a spaced pair at the edge of the case. The latter 3 were for overdubs higher on the piano, but I recorded all the tracks on all three takes.

All of these placements use an open lid, and I’ve used both cardioid and omni patterns to great effect. With a half stick lid, shoving mics inside gets trickier, but this might be preferable when other players are in the room. It’s also typical to use blankets to help isolate from the rest of the band. Half-closing the lid changes the acoustics inside the piano, but not THAT much.

Closing the piano entirely is another story. First off, you can’t stick booms inside a closed piano, and as I mentioned, room miking a closed piano doesn’t work. A traditional solution is PZM mics taped to the underside of the lid. With care, you can get cabling out of there without too much disturbance, and you can even pile on more blankets for isolation. The problem with putting PZMs inside a closed piano is a boxy sound. The inside of the piano is an insane place acoustically with the lid closed, and decent PZMs do an ok job, but it’s still tough.

There is a solution I like for that dilemma. It’s the Earthworks Audio PianoMic (reviewed in the September 2011 issue). The PianoMic mounts inside the piano (Figure 5), allowing the lid to fully close. The mics attached to the adjustable boom are what’s called “random incidence” mics, which means they “don’t care where the sound is coming from”. Basically, they’re “super duper omni directional”. This matters because sound inside the piano comes from all directions, making locating a specific source difficult.

Figure 5 – Earthworks PianoMic mounts inside the piano

Earthworks was kind enough to send me a loaner for this article, and I did some testing in an environment not ideal for recording: a showroom. Alex Boggs at 88 Keys Piano Warehouse here in Albuquerque (88KeysPianoWarehouse.com) generously lent me their space, where I installed the PianoMic on a baby Yamaha. The environment was relatively noisy due to street traffic and air conditioner noise, and I was curious how well I could isolate by closing the lid. I also tested with the lid open and at half stick. The playing masked the room and traffic noise, so isolation became less of a question. I really liked the sound; I did notice that with the lid closed, it was slightly darker and boxier, but less than I expected. What impresses me about the PianoMic is that it takes the guesswork out.

Figure 6 – PianoMic goosenecks can be re-posititioned

The mics sit on tiny goosenecks so there is some play (Figure 6), but really not that much choice in the grand scheme of things. This makes miking the piano less overwhelming. You sacrifice some flexibility, but I like the efficiency. I especially like that notion for live situations, and lo and behold, Earthworks makes a touring version of the PianoMic which breaks down more for easier transport.

Even with great mics, a closed lid is the least desirable scenario, but when you must close the lid, I like the PianoMic.

For an open lid, I already described spaced and X-Y pairs placed either at the edge of the case, or deep within the piano. I tend to gravitate toward the player, and I’ve spaced two 414’s as wide as the width of the piano, 2 inches from the strings, right up on the hammers. Another option is to bring that pair together, or X-Y a pair of small diaphragms right up near the hammers toward the middle. This will yield a percussive sound with a lot of attack. Any of these techniques might get you a lot of pedal noise, though, and depending on the player and piano, that may be too much.

You might solve that problem by going to an overlooked spot on the piano: the foot. In Nathan Rosenberg’s article on our website he says, “there is a wonderful place at the tail, just about where the back leg is, or often just outside the case. Here, the various registers tend to project in a surprisingly uniform manner.” That’s a good place for a mono recording, too. Thanks, Nathan!

Another accepted technique is to place one mic toward the middle of the group of high strings (toward the music stand) and a second more toward the foot of the piano. Typically these would be condensers in omni configuration.

Another extreme option is what Elton John producer Gus Dudgeon did – remove the lid. This allows you to hang mics above the strings almost anywhere your heart desires. It can result in a considerably brighter sound with less low end power, and that may not be for everyone, but some people swear by it. A spaced pair of omnis about 2 or 3 feet above the strings would be reasonable.

Of course there are the “sound holes”, which aren’t really sound holes, but can yield some interesting results. One technique involves an X-Y pair about halfway between the lid and case, pointed diagonally toward the strings. People have also been known to stick a directional mic right down into a hole, usually as a supplement to more traditional techniques (Figure 7). This is the one situation where a dynamic might suit you. I once put an SM57 in the middle hole, ran its cable directly to two guitar pedals (delay and distortion), ran that to a vintage Fender amp, and miked that amp like I would a guitar. I put the amp in an isolation booth across the room and closed the door and it was STILL feeding back! The point is, there are any number of creative things you can do, like miking under the piano to help bolster your low-end or for a mellow sound (Figure 8).

Indeed, there’s an endless variety of spaced pair, X-Y, mono and multi-mic configurations you can try. We’ve talked mostly about condensers because that’s more common, but in any of the situations I’ve described, you could substitute ribbons. We’re not done though. We haven’t talked about the mid-side pair, which can be a great way to use ribbons.

A mid-side pair makes use of two mics to create 3 tracks. Mic 1 – the “side” – must use a figure 8 pattern. Mic 2 – the “mid” – is a cardioid, pointed at the sound source. The side mic is perpendicular to the mid, so the figure 8 is left-right of the source direction. Once recorded, the side is doubled and one side is phase-reversed. These two tracks are panned hard and the mid is placed in the center. You can then mix to taste. A mid-side pair can be quite beautiful on a piano, and is perfectly mono-compatible since the 2 sides will cancel when summed. Placement of an effective mid-side pair for piano is similar to other placements – there are plenty of great possibilities. The other day I set up a mid-side pair at the edge of the case (Figure 9), right where I would normally put a spaced pair.

Figure 9 – Mid-Side pair at the edge of the piano

I loved the result. I also loved the result when Houston engineer Rock Romano recorded me with a mid-side of ribbons placed about the middle of the piano, with the cardioid pointed right at me. However, I do find that a mid-side can go wrong a little easier than other techniques. The experimental set up in Figure 10 was placed near the edge of the case a little higher, and I found the result lacking depth and character. I ended up killing side two and panning the mid left and the original side right to salvage the take.

Figure 10 – Mid-Side pair higher near the edge of piano

That brings me to a point on mixing. It may seem there’s no room to play in mixing a piano, but that’s not true. Especially if you use multiple mics, there are many ways to experiment and adjust. For example panning an X-Y closer together is always an option. A spaced pair will start to change tonally as you bring the panning in (because of phase issues), but that tonal change may be something you like. Just as there are no wrong ways to mic a piano, there are no wrong ways to mix it.

Before I end, I’d like to give my promised lip service to uprights.

Upright pianos aren’t recorded nearly as often as grands, and the reason is simple: they don’t sound as awesome. But that doesn’t mean it never happens. Some general concepts still apply. Condensers and ribbons usually work better, spaced pairs have more phase issues than X-Y pairs, and close miking yields less room sound than getting farther away. The upright is physically different though. So where do we place mics? There are three basic possibilities: Inside or above the top (with the top open), in front of the piano underneath the keys, or behind the piano. Upright pianos are often shoved up against a wall, and it’s probably best to not do that. It’s also probably best to remove panels either in front or in a back, to give better acoustic access to the sound board and strings. My personal preference would be a spaced pair of cardioid condensers placed about 2 feet off the ground, right about even with either side of the bench, so the piano player kicks them when sitting down or getting up, with panel removed. I once shoved a cheap dynamic into a 100 year old out of tune monster and the result was…magnificent…in its way.

By now you’ve got the picture that piano miking is a complex and variable task, with a lot of room for creativity. I’ve covered as much as I could, leaving out one big possibility: surround. That’s a can of worms that I think deserves its own article. Talking about piano miking is by no means simple, and neither is getting what you want from such a complex instrument, but I hope you’ve at least got some places to start now, and at best, a better idea of what to expect when caging the beast named Piano.

In case you’re wondering, I put together a bunch of notes and samples from my session with the EarthWorks PianoMic – you can get all that stuff for free right here.

Mixing, EQ and Processing Questions

November 9, 2006 by Aaron

audio, audio questions, eq, equalization, mixing, processing, recording

I believe this is the last of the questions from years back that I have left…again I don’t find anything I said blatently dumb, but it’s interesting to see this old point of view…

Questions

I am a single acoustic act. Guitar and vocals. I use a Takamine FD360SC which I play through a Trace Elliot TA100R. For vocals I use a Shure Beta 58. Both are connected to a Mackie 1402VLZ. The Beta via channel 1 XLR and the Trace via a DI socket (pre or post eq). The Trace has a 5 band graphic eq, which I am currently leaving flat, it also has several onboard effects such as reverb and delay which I am not using. Both are eq’d at the board via a 3 band parametric eq. It never seems to me as though I am getting the correct mix! I generally boost the mid and the high on the vocal while leaving the low flat. I then boost the mid on the guitar and leave the high and low flat. Any golden rules ? Hopefully you will bear with me for a couple more questions, if not…I appreciate your time on the first. The next questions deal with effects. I have used reverb for years (Alesis Midiverb which is a 1/2 rack unit which I generally leave set to factory preset 21 “Medium/Warm” 1.4 sec delay). I am now using an Alesis Nonoverb for delay (because I don’t like ANY of the reverbs). Input and output set 3/4 of the way up and mix set 1/2. I don’t feel as though I am getting the most out of these effects. Any suggestions ? (Please don’t say “buy a Lexicon!”). Finally, I am considering adding the following: Compressor Rack mount Eq Chorus Noise gate Is there any particular order in which I should daisy chain them ? I want to run two loops one for guitar and one for vocals. Which effects should I dedicate to vocals and which to guitar ? My plan was: Vocals: Reverb+Delay+Eq+Noise gate Guitar: Compressor+Reverb+Delay+req+Noise gate

Answers

the golden rule is really really tweak a LOT until it sounds right 🙂 …vocals and guitars can clash, so you might try eqing them in opposite directions, like maybe CUT the mid on the guitar a little…usually to start with on vocals I cut the high a little, cut the low a little and boost the mid a little. Sometimes I totally cut the high and low and boost the mid all the way. I call that telephoning, although with that three band eq, you can’t really make the actual telephone effect exactly. but as a matter of fact, that extreme eq on the mackie sounds surprisingly normal on some mixes – unfortunately I doubt an accoustic guitar/vox mix would be one of those mixes 🙂 Sounds like you need to take a little more time with the mixes, and tweak everything in every direction just a little more. Also, the mixes might actually be pretty good, but your ears are tired – get 2nd opinions – also, if you’re going for a sound that sounds like you’re used to hearing on records, you’re probably missing some ingredients (like reverb and compression)
Don’t buy a lexicon, I’m really against buying the biggest baddest stuff without first pushing what you’ve got to the total limit. Well first off, learn the ins and outs of editing the effects (again the golden rule is play more) instead of just using presets….uhm, use them in layers, use them in extremes, use them very subtly – basically just spend more time running the gamut and experimenting – uhm…I would set the mix all the way wet, then feed the reverb returns to a channel on the board and mix the effect with the dry signal that way (and also, you can use the eq on the channel if you need to on the effect) – also if you’ve got a natural type sound (ie: guitar and voice) maybe you don’t want to use electronic reverbs so much – maybe you should find a great hall and record in there (I know I know, good luck on finding a hall 🙂 ) – then turn around and use your reverbs for some other kind of project – mostly though, just spend more time I think – every mix you do, go through every preset and see what’s the best, then if something isn’t PERFECT, start editing and tweaking – try everything under the sun

well some people other than me would probably know better and maybe tell you different, but here’s how I would chain them, assuming that this is to run an entire mix through: chorus, compressor, eq, noise gate although I wouldn’t run an entire mix through a chorus, and I wouldn’t neccesarily keep the setup the same for all projects – that’s another part of my little golden rule about playing – you should see how much repatching I do (I wish I had a magic digital auto-routing super patchbay 🙂 )

I would add compressor to vocals and maybe take it off guitar. you almost always need compressor for vox and I’m not sure I’ve ever compressed accoustic guitar. like I said though, for the effects, I wouldn’t have them in an insert loop (that is the delay and reverb) – what I do when in a studio where I can do this is, I have compression on the vocals on an insert loop, and effects like delay and reverb triggered with aux sends and returned to an actual channel on the board.

—
So yeah there’s those – if you want more, just email me a question at aarontrumm @ nquit . com and I’ll give you my opinion, which is mostly what it it is when you talk about audio and art. 🙂

Meanwhile, you can still grab free tracks over at my music download site. 🙂

— Aaron

Graphic EQ or Parametric?

November 8, 2006 by Aaron

audio, eq, equalizers, graphic eq, parametric eq, recording

This is another one of the questions that came through 15 years ago that I didn’t lose – I definitely have a better, more sophisticated view now, but I don’t see anything blatently wrong here 😉

Question

…I have been setting up a decent home studio over time now, and would like to pickup a rack mountable EQ for use at mixdown and to cut frequencies on certain tracks, especially guitar… Would I be better off getting a 15 or 31 band graphic, or will something like the ART dual channel 4 band parametric tube preamp be enough? Will the tube quality outweigh the lesser band control in terms of sound quality? Will 4 bands be enough?

Answer

First off, I very very rarely mixdown with eq on the whole mix, but it can be a useful technique.
Well, ok. Obviously 31 band graphic is probably better than 15 graphic, and probably more expensive. Parametric eq tends to give you a lot more control (parametric meaning you can change the frequencies you’re working with). It’s kind of a trade off in my opinion. Parametric is better, really. But you tend to get less bands with parametric, which means less frequencies to be effecting at once. I guess parametric eq is more expensive to make or something. It would be nice to have 31 bands of parametric! 🙂 As far as the tubes, I wouldn’t take that into consideration for gear like this until the end. I use tubes, and I like to, but frankly, I defy you to hear them working 🙂 I don’t know that I see the value of using tubes in an eq, I tend to just use tube preamps to track through and run mixes through. That having been said there are tube-preamp units that have great eq sections, and I also might lean toward the Art, they make some cool stuff. As far as graphic eq’s, Rain pretty much makes the best, I think. As far as four bands being enough, think about your applications, and your possible applications. Will you need to be effecting more than four bands all at once? Like I said, with parametric, you’ve got all the control for dialing in what frequencies you’re messing with, so that might be the ticket if you don’t need to effect more than four at once. As far as tube quality outweighing having less bands, no. I think you should never put tubes before functionality. If you need to get something without tubes so it’ll do what you need, get that, save up, and get a dual tube preamp to run the whole thing through. Also, by the way, you should know that quite a few engineers think the tube thing is crap (I don’t, like I said, i use ’em and love to). So it’s not necessarily a given that tubes are even better. And by the way, tubes burn out eventually.

—
And that was that question. Hmm – let me know if you have questions too – hopefully I have more and better info to answer with! aarontrumm @ nquit . com

And – get you some free music, while you’re at it, so you can see what I do with this “knowledge”.

A vocals mixing question

November 8, 2006 by Aaron

audio, mixing, recording, vocal mixing, vocals

Many (like 20) years ago, for a short time, I opened up to questions on my site and people would email me stuff…I have just a couple of those that haven’t been lost and here’s one…

Question

…you know how some CD’s are mixed so that the singer’s voice sounds “farther away” from your ears with the headphones on? and some sound very up close and in your face? well basically, my voice sounded way to up close and i was wondering how to get it to sort of blend in better with the rest of the mix. this may be a silly question but like i said, all of my recording so far has been instrumental so i havent had to worry about it so much, and of course i am self concious about my voice right now. i dont think its simply the recording level, because that just makes the sound quiet, but doesnt change the sound in the audio field. so is it a question of mic type or placement? or of how it is mixed? or some other professional equipment effect that i dont know about? i would love to hear your thoughts on this!

Answer

Actually this can be a tricky thing for me too. You’d be surprised that sometimes it really is level…try lowering the level on the vocals. Also yes mic placement is important. You definitely get a different sound if you stand farther away. 1,2,3 feet and even farther are all different distances I’ve used. Also, reverb can be what you’re looking for. If you try adding a little more reverb and and less of the dry vox in the mix, it tends to sound “farther” away. Sometimes maybe even eq will help you here (with eq on vox I almost ALWAYS roll a little low end off, give it a little extra hi-mids and a tiny bit more high end). Sometimes I try making the vox a little thinner. Sometimes I try the opposite of what I’m thinking, and that sometimes helps. Try doubling up the vocals. (doubling up sometimes cuts through my self consciousness too…don’t do it unless appropriate though)…tweak a lot, try all the things you can think of…also compression…technically, compression will do the opposite of what you’re asking, but compressing the vocal is so common, that to your ear, it’s gonna’ sound more like a finished recording and thus less like naked vocals…at least that was true in my mind on a number of occasions.. Watch out for your self consciousness though. You could be getting mixes that are perfect, but sound WAY out front to you, because you’re scared (let other people hear the mixes…I try to have one or two very select people in the room with me mixing, or at least have them listen later). I always take what the vocalist tells me about the mix with a grain of salt. They (vocalists) almost always bury their vox. You should definitely try things out…try way too much reverb and not enough dry signal, and see what that does, etc…on every mix I’ll try one extreme and then another, and everything in between, just to see what the stuff REALLY needs to sound like. First thing’s first though, get over that self consciousness! 🙂 If you’re a guitarist singing some vocals, become a vocalist too. Take lessons, if that’ll make you feel more confident (it probably will, since it’ll probably make you better). If you’ve already taken lessons, take some more. I don’t know how good a vocalist I am, but on my recordings, I am confident and do whatever I want (even when I shouldn’t probably 🙂 ); one of the reasons is I took a singing class and it scared me to death and that helped; also I ALWAYS sing in my truck driving around (break the speakers in your vehicle, you’ll see *grin*) Make it a point to sing in front of people. Not just at concerts, but always. I don’t know how much of this stuff you already do, but it helps your MIXES, trust me. Also, record your voice a LOT. every DAY make three or four acapella vocal recordings and maybe even some spoken word and listen to it a lot (they don’t have to be good recordings, in fact vary it a lot, listen to your voice in lots of different contexts). You know, get real used to hearing your voice on tape, ’cause it sounds different. I’ve recorded hundreds and hundreds of songs (way way way more than I’ve released, I mean some were on a freakin’ boom box, but hey, I got used to hearing my voice on tape)…all this so you won’t bury your vocals in the mix. 🙂 Now just watch out you don’t get cocky and crank ’em up too much!

An added ps: Don’t mix with the monitors loud. Vocals tend to get too hot in the mix this way. Also you burn your ears out, of course.

It’s quite alright with me, btw, if you want to send questions like this – I’ll post answers – I’m at aarontrumm @ nquit . com 🙂

Meanwhile, grab some free stuff over at aarontrumm.com 🙂

Basics Of Analog Audio Mixers

November 6, 2006 by Aaron

analog mixers, audio, basics, signal path

From a 1994 article for the University of New Mexico’s Intro to Electronic Music class:

Signal Flow:

Mixing boards contain multiple “channels”, each of which has separate input, and is controlled separately. These channels are then assigned to either a “buss” or a master output. Every channel assigned to a given buss or master is mixed together and output in it’s blended fashion through the output jacks corresponding to each buss or master output.
Channels on all mixers (with rare or no exception) have either an On switch or a Mute switch, or both. On switches simply turn that channel on. If no sound is being output of a channel you think should be outputting, the first thing to check is the On or Mute switch. Mute switches do the opposite. They turn the channel off. If an On switch is not engaged, no sound will be outputted. If a Mute switch is not engaged, sound will be outputted.
Signal fed to a given channel’s input procedes first to it’s trim section, which allows the input level (volume) to be adjusted; then to it’s EQ (equalization) section, then to the Pan-Pot, which simply adjusts to which side of the stereo spectrum (see stereo concepts) the channel is placed, then to that channel’s “fader” (or gain knob, depending on the board). A fader (or gain knob) is simply a volume control. It controls how much overall level is being output from that channel. This signal flow is represented somewhat by the physical layout of each channel. Input jacks are at the back, Trim knobs are next, then EQ section, then Pan-Pot, then Fader.
After flowing through Trim, EQ, Pan-Pot and Fader, signal is fed to all busses or master outputs that a given channel is assigned to. For example, if a channel is assigned to buss 1 (usually by pressing a button above or near the fader), then signal will be fed to buss 1, buss 1 will output that signal. Busses are simply outputs. All busses have a volume control of their own. That volume controls the overall level of all the sound being fed to that buss (meaning this sound is usually a mix of many channels).
Their are two basic configurations for output on mixing boards:
$nbsp$nbsp$nbsp 1) All busses are automatically fed to the mixer’s outputs (which usually consist of at least two sets of outputs: one pair for monitoring, and one pair to go directly to tape. “Monitor Out” and “Tape Out”).
$nbsp$nbsp$nbsp 2) The mixer has a “master left-right”, (which is simply the main master control buss) and individual busses can be assigned to that output. In this case busses are not automatically outputted to the master output jacks. In either situation, most boards have another set of output jacks, which correspond to each individual buss. (For example, if their are four busses, there are four “buss output” jacks, in addition to the master output pairs.)

Common Channel Characteristics:

INPUT – Channels on most boards consist of at least two input jacks (usually at the back): 1) Line input. This is usually an RCA (or “phono”) jack or Quarter-Inch (large “headphone”) jack (although really high-end professional equipment rarely uses anything except XLR connectors, even for line input…most good boards have a choice). This input accepts line-level input, that is, input that does not need to be boosted before proceding to the channel controls. Examples include cassette decks, CD players, Synths, etc. This input is usually labeled “line in” or “tape in”, or similar (sometimes there are both “line in” and “tape in” jacks. They are essentially the same).
2) Mic input. This is usually an XLR (three-pronged, or “cannon” input) connector, but it can be other types. This input accepts mic level input, that is level that DOES require boosting before it will be at an acceptable level before proceding. Examples include, of course, microphones, and assumably some other devices that ouput at mic level. This boosting is done by the Pre-Amp section of the channel. This input is usually labeled “mic” or “mic input” or simaler.
DIRECT OUT – Channels usually consist of a “Direct Out”. This is (as far as I know) always a line-level ouput. Direct out jacks consist simply of the signal that is being output of the given channel. Direct out jacks are not effected by other channels, busses, or master output levels. Plugging into a direct out does not effect the channel’s output into busses or master outputs, and does not interfere with the flow of that channel into a mix.
INSERT or ACCESS – Channels usually consist of an “insert”, or “access”. This can be accomplished in one of two ways: Either with one jack, that outputs the channel’s output, then returns it, within the same jack, or with one jack that consists of the channel’s output and another that returns it. Inserts interupt the signal, and thus allow you to “insert” another device into that path. (An example is a person may use the insert to take the output of the channel to a compressor or effects processor, then return the modified sound to the channel…the modified sound is then what is fed to any busses or master outputs.) Plugging into an insert DOES effect the channel’s output to any busses or master outputs. It does NOT effect other individual channels.
INPUT SELECTOR – Channels must have an input selector switch if they have more than one input jack. Typically this switch chooses either the mic or line input. IE: If the switch is switched to “mic”, then input for the channel will be accepted from the mic jack, and not from the line jack, and vise-versa.

Thanks for reading! This was quite some time ago but still applies. If you want some current flavor, I’ve got free downloads available!

— Aaron

Basics of Equalization

November 5, 2006 by Aaron

aaron j. trumm, audio, eq, equalization, music, nquit music

From a 1994 article for the University of New Mexico’s Intro to Electronic Music class:

Equalization is a process of enhancement of audio signal. It is one type of signal processor, because it processes an audio signal.

Equalization (EQ for short) does basically one of two things: Either it boosts or cuts a given frequency or range of frequencies by a chosen level.

Outboard EQ processors come in two basic flavors: Parametric and Graphic.
Parametric EQ uses a system that allows a user to select which frequencies they’ll be working with. Thus, it is very flexible. Fully Parametric EQ has completely selectable frequencies and bandwidth. Some EQ’s are semi-parametric, meaning they have some, but not complete, flexibility. Most mixing boards use some sort of semi-parametric EQ (although many use a system that is not parametric at all, but cannot be called graphic).
Graphic EQ has no method for changing any of the frequencies that are effected, but still can be quite flexible, if it has a wide variety of bands. Graphic EQ derives its name from the fact that its sliders are configured in such a way that when a user look at them, they graphically represent the configuration being used.

Mixing boards use an EQ system that is not usually truely parametric, but it is not a graphic system (since, of course, it does not use sliders that graphically show the configuration). Many boards use a fixed band EQ in which each knob effects multiple frequencies, such as high, mid and low (unlike graphic EQ in which each slider boosts or cuts only one frequency). Many boards use a semi-parametric system in which some sections of the EQ have a knob which will choose a frequency, which is then usually accompanied by a bandwidth selector, which chooses how wide an area of frequencies will be effected. (This is nearly true parametric EQ, but usually only one or two frequency ranges provide this option, so we don’t normally call this a truely parametric EQ system.) Some boards have sections of their EQ that are semi-parametric, because the frequency effected can be selected, but not the bandwidth.

EQ is used for many purposes, including enhancing an audio track, making a track more audible in a mix, fixing noise problems, helping audio tracks to sound more real or artistic effects such as “telephoning” (my word, meaning to cut low and some high frequencies, making a track sound as if from a telephone).

The Art Of Equalization

November 4, 2006 by Aaron

aaron trumm, art, eq, equalization, music, nquit music

From a 1994 article for University of New Mexico, and published in Cubase Newsletter:

EQ can be used in a variety of situations, from live sound to recording to tape to mixing down. Mainly, it should be used to enhance signals that have some problem. The golden rule of EQ is less is more. If something seems fine without it, I avoid EQing it at all. Then, if I do use it, I try to remain subtle. My personal golden rule is nearly never EQ signals going to tape (as in a multitracking situation). I always try to get the original sound on tape, then I can mess with it later. Putting EQ (or any other effect) on tape usually just leads to trouble. The other rule (the silver rule 🙂 ) is cutting is almost always better than boosting, especially when fixing problems. For example if a guitar sounds too thin, first try cutting high frequencies and boosting the gain a bit, instead of boosting the lows. The more clutter you can remove from a mix, the better. A better example is I very often cut a bit of high away from hats. Another example is, many times you may not hear something well in a mix…You might try cutting some frequencies in a different track that seems to be interfering, rather than boosting in the track you want to bring out. With these basic rules in mind, I’ll tell you my rules when I enter a mixdown session:

Rule Of Opposites: Usually, tracks with high sounds, (a high guitar, hats) need cutting in high frequencies and boosting in lower, and vice-versa. This is really only a starting guide, not a rule. Also, sounds that interfere with eachother can be separated in a mix by EQing them in opposite directions.
Bass usually needs a boost in the mid range somewhere and sometimes the high. This way it can cut through and be heard on smaller speakers.
Kick drums usually need that same mid and/or high boost on a subtle level so they too can cut through on smaller speakers. For hip-hop, kick needs a low end boost, but NOT TOO MUCH.
Snare drums always sound warmer with a boost in the low-mid range and some cut of the highs. An annoying CRACK can be softened with this high cut. Sometimes I boost the lows in snares to make them even fatter. But it really depends on the snare sound. The rule of opposites usually applies here. Snare sounds that were thin to begin with I usually warm up a bit, and heafty snare sounds I might thin out a bit.
Hats almost never need any EQ if they’re recorded clean. Usually an EQing for my hat tracks is to cut highs to get rid of an annoying hiss.
Guitars are simaler to snares for me. A thin original guitar might need boosting in mids and lows (depending on what the desired sound is, and what else is present in the mix) or a heafty guitar might need to be thinned out a little by cutting lows and low-mids.
Vocals usually like to have a boost in the mids or high-mids, but it depends on the voice. Vocals nearly always get lost amongst guitars…a good way to deal with this is the rule of opposites. Boost mids in the vocals and cut them in the guitar, or something similar. Vocals can also have annoying hiss or sibilance, and sometimes cutting high frequencies can help that.
Strings, and more specifically good string patches from a synth, usually need little EQ. If they are merely a support player, I may thin them out a tiny bit, or if they are meant to be present, I may thicken them in the mids a little (or sometimes the opposite…this stuff is highly subjective). But they usually work well left alone. Really clean piano or keyboard synth patches are the same way.
I like to leave reverb returns alone, but if the reverb becomes annoying and noisy, cutting some high can soften it up a bit…same with strings.
Extreme EQ setting create sounds of their own. Experiment. But for a non-novel track, be subtle.
AC hum from a track can almost always be fixed by cutting 60 Hz all the way off. (Sometimes this can take away from bass or kick sounds, but I believe that most frequencies audible in a song are above 60 Hz).
Play with EQ settings thoroughly to find appropriate settings.
I don’t mix horns too often, but when I do, I like to leave them alone. Clean horn tracks usually seem fine to me.
NEVER EVER EVER force yourself to EQ a track that sounds fine, just because you think you should use the full capabilities of the studio. NEVER NEVER NEVER!