Home & Studio Recording (February 1993)
By Nick Batzdorf
Do the police show up every time you mic your guitar amp? Here's a low tech solution that'll save you having to clean the printing ink off your fingers.
For the benefit of both H&SR readers who don't know this, you can't get that characteristic electric guitar sound on tape without boosting the guitar amp until it distorts. Problem is, that makes the walls come tumbling down... if not from the force of the amp, from neighbors pounding on them! And in the studio, electric guitars have a nasty way of making snares rattle sympathetically and generally leaking all over the place.
The Battle of Jericho
There have been a number of electronic solutions to these problems, all of which involve DI'ing (direct injecting); that is, taking the guitar's output directly to tape. "Direct" is somewhat misleading, as you don't actually plug the guitar directly into the tape recorder. What the term really means is that the electric signal gets recorded directly from the guitar's pickups without being converted back to moving air; in other words, without going through a speaker and a microphone.
Instead, the signal usually goes through some kind of guitarish signal processor. These processors include amp simulating devices, such as Tech 21's Sansamp and the Scholtz Rockman, and multieffects processors that have instrument level inputs, such as Ensoniq's DP/4 and various processors from Zoom. Of course, you can also run a guitar through an effects processor that doesn't have instrument level inputs, most often by using a mixer to raise the level appropriately.
Then there are speaker simulators. Devices like the Marshall SE-100 and Scholtz Power Soak (which has jut recently been reintroduced. See 'Fast Forward') simulate the load of a speaker to trick the amp into thinking that it's driving one, so you can turn it up and use its distortion without its volume level. Other devices emulate the sound of the speaker itself, which also has an effect on the sound. It's also common for both speaker and amp simulators to be used in combination. The Ensoniq DP/4, for instance, has algorithms for both.
Devices of this ilk are used to good effect on recordings every day. However, none of them have yet convinced purists that they can completely replace the "air" you only get the old-fashioned way: miking an amp. Which brings us to the Demeter box.
Inside the Surface
It couldn't be simpler; a sealed box with a speaker and a mic in it designed for recording cranked electric guitar without breaking all your wine glasses. The inside of the SSC-1 is insulated with Dacron (just like in your sofa), with space for a speaker and a mic holder. There's a door so you can put the mic in and place it in the best position, and also so you can install the speaker in the first place! The box has space for a 12" speaker which, like the mic, is not included.
There are two jacks on the outside of the box: an XLR mic output and a 1/4" speaker input. The review unit was covered with short-haired black fuzzy material, but it's also available in tweed, carpet, and "simulated reptile coverings." My first choice would be Pterodactyl.
3/4" marine-grade plywood is used for the handmade box. The dimensions of the SCC-1 are 20" x 30" x 20"; Demeter also makes a larger SCC-2 stereo version, which has two slightly smaller chambers of the same type. The whole thing is quite solid, and the hardware is the same type you'd find on a flight case; you know, metal corner protectors, a padlockable twisting thingie that locks the door (which must be tightened so it doesn't rattle sympathetically), rubber feet, and recessed spongy rubber handles that fold out and spring back when you're not using them.
I have to point out that there's no reason you couldn't make your own variation of this box and save a considerable amount of money. On the other hand, you probably wouldn't end up with the same quality of construction. And one could say the same thing about lots of furniture; wooden equipment racks, for instance. Suffice it to say, the Demeter box is a high quality box that's priced accordingly.
One particularly nice feature of the SCC-1 is that it doesn't scratch up your car seats while you transport it to Sound Chamber Studios in North Hollywood, CA for testing. Special thanks to owner Dick McIlvery, who provided some frightening guitar licks in Studio A... just a few minutes before its tenant (film composer Michael Kamen) was due back in for the day.
Will You Get to the Point?!
All right, all right. The review unit Demeter provided us with was ready to fire up; it had a Shure SM-57 mic and a Celestion Classic 80 speaker already installed. We drove it with a Mesa Boogie amp, which we also miked with an SM-57.
No one present at the studio is a human sound pressure meter. Furthermore, we can't claim to be "totally cool engineers," since we haven't yet acted upon Dave Moulton's advice about the $50 Radio Shack meter he says is the best bargain in pro audio (see his article on comb filtering, phase reversal, etc., in this issue).
That disclaimer out of the way, one would estimate that the Demeter box was maybe 30-35 dB lower than the live Boogie amp, which had been cranked loud enough to be totally annoying. Also note that this isn't a scientific test; the speaker inside the box wasn't the exact same model as in the Boogie, and the mics weren't in the exact same position along the speaker cones.
In real life, you'll find that the SSC reduces a screaming, and I mean screaming, guitar to the level of a stereo system being played at a moderate level. That's probably low enough for most apartments during other people's waking hours. It's not low enough to prevent the guitar from leaking into other open mics in a studio, however. For that, you'll need to get out the blankets, gobos, and so on.
Having come to those conclusions, I retreated into the control room while Dick conducted his own private guitar war. How did the thing sound? In a word, good. Dry, not very "airy," but... well, like a miked guitar speaker. It didn't sound "boxy," if you were wondering. The Boogie obviously had more room sound (it was in a room, after all!), but you can always add artificial reverb, delay, etc., to suit. The Boogie also sounded brighter, partly because the Celestion speaker tends to be slightly dark sounding, and also I believe partly because of the room reflections. While this is an A/B comparison of different kinds of apples, I would bet that you'd come to the same conclusions if both speakers had been the same and both mics were mounted in precisely the same position.
Many engineers like to use an ambience mic when recording electric guitar (often a high quality condenser or tube mic, rather than the dynamics, usually SM-57s, generally used for guitar amps), which is a technique that clearly defeats the purpose of the Demeter box. However, it's interesting that the SSC-1 sounds quite good as a speaker cabinet with its door open. The partial muffling produces a rather mellow sound.
Will the Demeter box satisfy purists who prefer the sound of a miked guitar amp? I would think so, unless they insist on natural room ambience. Should you buy it instead of an electronic guitar processor? I couldn't presume to make that decision for you. But one thing is for sure: it's a very clever idea.