Q: What carpet do you recommend for a studio floor?

Leaving aside questions of colour and pattern, what type of carpet works best in a recording studio environment?

A question from an Audio Masterclass website visitor:

What carpet do you recommend for a studio floor?

This is actually more complex than it seems at first. There are at least two questions here - one is what carpet is recommended for the recording area, the other is what carpet is recommended for the control room?

Conventionally the answer has been for a long time that no carpet is recommended - just bare wood or laminate flooring.

One reason for this is that carpet quickly wears out or becomes 'tired' looking, particularly in the control room under the engineer's chair, and in areas where equipment is loaded or stored. These areas should not be carpeted, for purely practical reasons.

The other areas can be carpeted if you wish. But there is a 'but'. Carpet is a great absorber of high and high-mid frequencies. Compared to other forms of absorption it's quite cheap too.

But carpet has little or no effect on low frequency sounds - it's too thin. So a room that is carpeted will have a lot of absorption at high and high-mid frequencies, a little at mid frequencies and none at low frequencies, unless other measures are taken.

This room will sound very dull because of the imbalance towards low frequencies in the reverberation of the room.

There are two solutions to this. One is to reduce the area covered by carpet and use a thinner carpet. The room will be more lively, but there will be a better balance of frequencies. The other is to provide low-frequency absorption, which can be done using proprietary modules, or by constructing panel or membrane absorbers.

You can actually make a low-frequency absorber out of carpet. Hang the carpet on the wall supported by a wooden batten spacing the carpet 50 mm or more away from the wall. Now fix similar battens all around the edges of the carpet, and nail the carpet down. Such an absorber will still have more high and mid absorption than low, but it's better than just carpet alone, and it can be balanced out with other acoustic treatment methods elsewhere in the room.