Tuesday, January 10, 2006

How close to place the mic?

One of the things I see many beginning engineers do that causes problems involves the placement of microphones. On guitars, amps, drums, vocals, everything.

When placing a microphone, you should consider the microphone's pickup pattern (omni, cardioid, etc), whether it has a proximity effect, and what sort of sound you're after.

Generally, in rock, we think of most sources being close-mic'd. That is, we place the SM57 just in front of the speaker grill, closer if we can get it! The same logic is used on drums, with close micing, the vocals, and the bass DI'd. While these may make sense in theory, you rarely get the best tones solely by close micing, and in many cases, you overpower the mic so that you're adding distortion.

My general technique for micing a guitar cabinet is to start about a foot away, with the mic pointing directly at the speaker. Listen to the signal and move back or closer to get a fuller or thinner sound. Contrary to logic, you get a fuller, meetier sound by moving away. This is because bass frequencies have longer wavelengths, and require more air to develop. Proximity effects counteract this somewhat, so some experimentation is necessary.

If the signal is weak, try turning the amp up. Listen to the amp with your ears plugged. You should be able to get a sense for the type of distortion coming from the amp. Whether it's overdrive or speaker breakup, a distortion pedal, etc, they all have distinctive sounds.

Now, listen to the signal coming through your monitors. It should have the same distortion, but no more. If you're hearing high end distortion that wasn't there at the amp, you need to move the mic back farther, or turn down the amp. You're likely overdriving the mic.

With bass amps, it's the same theory. I usually use a Large Diaphragm Condenser, about 3ft back from the cabinet. You have to listen carefully for distortion, it's easy to overdrive a mic with loud bass. Move in or out to get more presence and bass.

Drums are a whole other game. There's no easy way to mic a tom without getting right on top of it, if you want any degree of isolation. Adjust your tom and snare mics to get the best tone, watching to avoid overdriving the mics. If you're using condensers, be sure the pad is switched in. Dynamics are more resistant to being overdriven, which is a large part of their popularity for this application.

The kick drum, on the other hand, does require some experimentation, and because of it's location, you have a lot more freedom. You'll find that as you get closer to the kick head, you get more attack, more "boing" from the head itself. Moving away, as far as several feet outside the head gets you more bass and more sustain. Many engineers prefer to mic both, which gets you a full spectrum to work with. Be careful to check phase though.

Overheads are another place where you have lots of room to experiment. I won't go into too much detail, but keep in mind that the farther you get above or in front of the kit, the more reverberant the tone will be, and the more you will hear the room tone. If the room is good sounding, go with it. If it's not, get the overhead mics in close.

For vocals, you often need to have the mic a few inches back from the pop screen. Experiment with different distances, as the proximity effect of cardioid mics can have a big impact of the tone of the vocal track.

Room mics are another big part of the equation. I like to use room mics during tracking, to get the sound of the whole band on one track, which can be compressed, eq'd, etc. This way you can make the room more of the mix or less of the mix, to emphasize different parts of the song, or just get the right feel.

With vocalists, I'll often set up a room mic during their overdubs. Mixing a little of this natural room sound in can help glue the vocals to the rest of the backing tracks, helping them fit in the same "space".

Generally, you should experiment with mic placement, by starting as close as you might imagine is practical, then moving farther away. I've tracked acoustic guitars from 10 ft with great effect, backing vocals from 15 ft, and drums from across the room. Walk around and listen with your ears. If you find a spot where things sound great, stick a mic up.

Expensive mics and gear provide some of the colors on the audio engineer's pallet, but simple things like mic placement can provide more variation than you might imagine.

Tuesday, January 03, 2006

The Cult of the Mult

Getting started on this blog has been a bit of a challenge. There's a lot to say, tons of gear to review, ideas and suggestions, common questions, all sorts of stuff. To start off, though, I'll just jump right in with a technique that I use often, and one that I don't hear people reference as often as I would expect.

The Mult.

"Multing" is the practice of splitting a signal, so that you have the same feed going into parallel circuits. For instance, you might send a vocal to both a light compression with some reverb, and to a parallel circuit with very heavy compression and eq. When the two signals are recombined, you get a vocal that has the nuance of an unprocessed track, but with the presence and shimmer of one that has been 'cooked'.

To do this in the analogue realm, you can use a simple "Y" cable, or you can use a half inserted "insert" cable. In the case of the "Y", simply plug the cable from your tape machine into the "y", then plug into the line-in on two channels of your board. To use the Insert, simply use a patch cable halfway inserted, so that it taps the signal without interrupting it, then plug that into the line-in on another channel.

In the digital world, simply copy the track you want to mult, and paste into a new track, making sure that the start points are the same. In Cubase, for instance, you can option drag while holding down the command key (on Mac), to make a copy that is perfectly aligned with the original.

You have to be a little carefule about phase issues, as some processors or plug-ins introduce a small amount of delay, which can be problematic. I usually insert the same plug-ins on both copies, and leave one turned off, to correct for any latency issues.

So, now that you understand the basics, where can this be helpful?

Generally, anytime that you wish you had more signal to work with, a mult can be helpful. Say, for instance, that you have a great bass tone, but you'd like it to have some fuzz in the upper registers. You try putting a distortion or overdrive plug in, but now the low end sounds wooly and lacks punch. This is a good place to use a mult. Keep one channel sounding nice and tight, but run the other through a fuzz patch, then cut everything below about 2khz. Now you have a bass that has an articulate high end with some edge, and a low end that still punches and feels tight.

Similarly, you may find that a kick drum isn't punching through the way you want it to. In this case, you might mutl the kick, compressing one channel hard, with a bit of boost in the lowe frequncies. This will give you nice boom and sustain, but now the attack is pretty much gone. You can try slowng the attack of your compressor, but the results may not be what you're looking for. In this case, you can use the second track to get a nice crack around 5k, and a good punch at 1k. I like to use a gate on my "attack" track, so that it only opens for a few milliseconds. Then, after the gate, I run it through a distortion patch. This give a very bright attack, but without adding a bunch of noise to the whole track.

You can use the same approach on a snare. Sometime, I get too much bleed from the high-hat on my snare track. If I boost the highs to get a good clear attack, I get a ton of hat. If I try to gate it, it sounds too mechanical, and fake. The solution? The Mult, of course! Set up one track with some eq cut in the highs, a bit of compression, and some boost in the 200hz range. Now, take the second channel, and set up a tight gate. Let it stay open for maybe 50 milliseconds, so that fast rolls can keep the gate open. Now, eq this channel for the high attack you want. You can even limit it, or distort it. Whenever the drummer hits his snare, this cracking track will be audible just for an instant, while the first snare track rings out naturally.

I use mults all the time, and it's a useful technique for solving problems, creating larger than life sounds, and getting mixes that can compete with the big boys.

Have fun!