Isolating Your Speaker Cabinets for the Best Guitar Sound

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23/11/12 11.18Recording & Production: Isolating Your Speaker Cabinets for the Best Guitar Sound | Harmony Central

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Recording & Production: Isolating Your Speaker Cabinets forthe Best Guitar Sound | Harmony Central

Gain Without Pain: Giving the Guitar Cabinets Their Own Space

By Jon Chappell

For recording guitarists, one benefit of a head-and-stack configuration over a combo

is that you can separate the amplifier from the speaker cabinet and run a long cable

between the two. A speaker-level signal can travel a longer distance than can a guitarcable, so in a remote recording situation that requires really loud levels, youll some-

times see a head and cab in widely separated places. The head can be in the control

room, for example, close to the performer, who monitors through headphones or on

the studio monitors. The miked cabinet is then placed in the live room, a safe distance

away and separated by double-pane glass. The live room often has a desirable ambi-

ent sound, which can also be miked and mixed into the close-miked signal (which is

the normal way to record guitar cabs).

But home recordists can emulate this setup as well, though perhaps with not quite

the elegance of a control room for performance and a live room for hosting the cab

and a mic. If you have a head and cab, consider separating them and connecting the

cab through a long speaker cable (use a tape measure to estimate the separation

distance, and make your purchase accordingly). Then mic the cab and monitor thesound through headphones. The better isolated the cab is, the more pure your moni-

tor sound will be. And one of the best ways to isolate the sound of a cab is to move it

further and further away from your years. Insulation and soundproofing are good,

but since sound level diminishes as a function of the inverse square of the distance,

turf is what counts here.


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REMOTE MIKING ON THE CHEAP

Fig. 1 shows a schematic of the basic separation principle. The performer is in one

room with his amp head close by. In the next room is the cabinet. Having the speakerin a bathroom (as is the case here) has the additional benefit of contributing a nice,

natural ambience, courtesy of the tile floors, porcelain fixtures and hard walls.

Note that in Fig. 1 there are three cables involved. In order from short to long, theres

1) the guitar cable that plugs into the amp. This you want as short as possible, prefer-

ably no longer than 20 feet. Thats obviously no problem here. 2) Next is the speaker

cable, which travels from the back of the head (here on the right side as you face the

head), out the door, and into the next room where it plugs into the back of the speak-er cabinet. 3) Last is the mic cable, which travels all the way from the mic in front of

the cab, back through the open door, along the foreground of the room, and up the

left side of the mixer. If the performer can squeeze the door shut (with the two cables

between the bottom of the door and the floor), hell have an easier time monitoring

the sound over headphones or studio monitors.
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Fig. 1: The basic strategy is to place the cab in a separate room and connect it to the

head with a long speaker cable. You mic the cab and run that cable back to the mixer.

The performer then monitors the miked cab sound over headphones or studio moni-

tors (click to enlarge).

Running cables between rooms works surprisingly well. Of course, you can always

augment the distance advantage with insulation or even simple padding. Fig. 2

shows a miked amp in a corner, buttressed on one side by a big couch. Note that here

the head sits on top of the cabinet, eliminating the need for a long speaker cable. For

set-and-forget situations, or where you wont be tweaking the amp knobs often, youcan keep the components together. And this is the scenario for using a combo, where

you cant separate the amp controls from the speaker.

Fig. 2: Placing an amp in the corner and flanking it on one side with padded furniture

will provide added effectiveness along with distance (click to enlarge).
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HOME IMPROVEMENT

If you own or otherwise can alter the floors and ceiling of a multi-storey dwelling,

you can put the cabinet on a different floor. For example, with the amp and recordingsetup in a first-floor den or family room, you could pass a cable to the basement room

directly below, where your cabinet will live. It doesnt matter what room is in the

basementit could be a garage, a laundry room, or the utility closet housing the

furnace. As long as the cabinet fits in the space directly below (or nearby) the hole,

youre fine.

What youll do in the split-storey scenario is either run the cable outside, through

open windows (better for temporary situations), or drill a small hole in the floor (and

through the ceiling of the room below, if necessary). Youll then pass a speaker cable

through the hole to connect the head with the cab. If your mixing board is near the

head, youll also pass a mic cablethe one connecting the mic and the mixer

through this hole as well. Needless to say, this is a permanent, aesthetic modification

to your floor, so careful thought must be appliedand permission grantedbefore

embarking on this particular home improvement.

But more and more, holes are getting drilled into floors to accommodate cable

communications, especially when retrofitting older dwellings, which dont have the

cable built into the walls. A first-floor-to-basement connection is ideal because the

ceiling in most basements isnt aesthetically pristine nor hard to break through, as

one between, say, a first and second floor. In my own case, my basement has just a

drop ceiling with acoustical tile. If you remove a tile, you see the floor joists and the

exposed floorboards of the room above. With an assistant, we determined the ideal

location from both above and below, and avoided having to drill through a joist in

the process.

To get through the floor, you need any battery-powered cordless drill with a router

bit. Choose the bit based on the size of the hole ou need to make. Note that m drill


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(see Fig. 3) is an 18V, but you dont need one that is quite that powerful. A smaller,

14.4V drill will do the job fine. The bit pictured here is a 5/8" router.

Fig. 3:An ordinary cordless drill is all you need to make a hole in a floor or drywall,

through which youll pass your mic and speaker cables. Shown here is a 5/8" routerbit, but you might be able to use a normal straight bit (click to enlarge).

Very important tip:Before you drill anything, consider that you only need the hole to

be big enough to pass the actual cable through, and not the connector (usually an

XLR) and the cable. To make the smallest hole in your floor possible, first remove the

connector by de-soldering all three leads. Pass the cable through, then re-solder the

connector on the receiving end, on the other side of the obstruction (floor and/or

wall). In my own case, I wasnt concerned with making an absolutely minimum-sized

hole, because the hole location was in a corner that would eventually get covered

with carpet. Fig. 4 shows the hole with the carpet pulled back.
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Fig. 4: A 5/8" router bit (shown at right) will make a hole slightly larger than a dime

(which sits just left of the hole; a nickel is above and a quarter is below). This easily

accommodates one speaker and one mic cable (click to enlarge).

My 5/8" router bit makes a hole that is only slightly larger than the diameter of a

dime. This will easily accommodate two cables with no threat of binding (though the

cords are more or less permanently placed). But you can make the hole even smaller

if you like. If you really need to go small, and youre not sure of the diameter, prac-

tice making holes in a scrap piece of wood, and fit your particular speaker (and mic)

cable through the hole to ensure the fit. You might be able to use a normal drill bit de-

pending on the diameter of your speaker (and mic) cable.

Fig. 5 shows whats under the hole in the floor on the storey above. Hey, its my

basement, full of junk (some of it musical). But this room is basically for storage and

remains largely unoccupiedespecially when the 100-watt head is exercising the

4x12 speaker cabinet! When I use this setup, I listen to the mic signal that comes

through the headphones. Im not in the same roomor even on the same flooras

the cabinet. This allows me to et a ood authentic sound out of the am and cab
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(read: I can play really loud) without blowing out my ears. With headphones on, Im

only faintly aware of the subterranean rumbles below, as the cab vibrates the floor

underneath my feet.

Fig. 5: The miked 4x12 amp cab resides in the basement where it can produce inhu-

manly loud levels. The speaker cable that connects it comes from the floor above;

note how it passes through the acoustic tile in the drop ceiling at the top of the photo

(click to enlarge).

CONCLUSION

In many cases youll want to use high volumes from your amp to inspire a perfor-

mance or to facilitate feedback. But there are often times when its just as beneficial to

separate the performer from the thing making an unholy racket. Whether you use a

head and cab or a combo, consider separating the performer from the ampespecial-ly if you have to play and record simultaneously. While it requires an adjustment,
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when youre the engineer as well as the performer, youll get a more objective picture

of what's going to disc from headphones or studio monitors than from the actual

sound coming out of the cab.

Jon Chappell is a guitarist and the Senior Editor of Harmony Central. He has

contributed numerous musical pieces to film and TV, including Northern

Exposure, Walker, Texas Ranger, All My Children, and the feature film

Bleeding Hearts, directed by actor-dancer Gregory Hines. He is the author of The RecordingGuitarist: A Guide for Home and Studio (Hal Leonard), Essential Scales & Modes (Backbeat

Books), and Build Your Own PC Recording Studio (McGraw-Hill), and has written six books

in the popular For Dummies series (Wiley Publishing).
http://jonchappell.com/

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Isolating Your Speaker Cabinets for the Best Guitar Sound