Get a closed-back cab sound from an openback cabinet.
Closed-back cabinets give a very different sound compared to open-back types: They tend to generate more low end, and a “tighter” response. In the studio, closed-back amps give you two tonal options—but if you have only an open-back combo amp, here’s a technique for getting a closed-back sound out of the same amp. No woodworking required!
The trick is to place your open-back cabinet so the back of the cabinet lies flat on a rug, flush against the floor. Not only does the floor block the cabinet back, but the rug helps absorb some of the sound as well. To mike the amp, you’ll need a boom to point the mic down at the speaker.
Ideally, its input jack will be on the front, and the rear power cable connection will be recessed (as is the case with the Peavey Windsor amp shown in the picture). This configuration lets the AC line cord feed out the side; if this process raises the back up too much off the ground, thus defeating the closed-back effect, a right-angle female AC connector may do the job. Otherwise, you can always cut a small slot in the side of the cabinet as a cable feed-through.
However, note these important cautions. In many amp designs feature ventilation through the back of the cabinet, so putting the cab on its back could block the airflow; this can be particularly problematic with tubes. In this case, you’ll need to monitor temperatures carefully, and record for as short a period of time as possible. Whenever you take a break, move the cab back to its usual position to let it vent for a while—note that even if the amp appears to be performing properly, heat buildup can reduce component life. —Craig Anderton