Bass/Room probelm


I have theil 2.2s that are place four feet out from the back wall (all glass) and 3 feet in from each side wall in an L shaped room that is roughly 24 ft by 22 ft with a 11 ft by 11 ft inset in one corner. Using a radio shack spl and stereophile test cd (vol 1)my bass response measures (and sounds)10db higher than normal at 31 hz and 10 db lower than normal at 64 hz and is otherwise pretty flat from 20 hz to 150 hz. What is going on? Is there anything I can do to address this with speaker placement/ room treatment etc?

Thanks

Greg
kadlec

Showing 1 response by audiokinesis

Well said, Sean!

There is a way to make an end run around the bass problems in a typical room. And that is to start out with speakers that adequately address the situation.

One such design is the Gradient Revolution, whose dipole bass loading results in exceptionally smooth in-room response. Okay I'm not normally one to get excited about numbers, but sometimes something you can hear shows up in measurements, and it strikes a chord. In 1997 Stereophile's John Atkinson measured the smoothest in-room response they ever recorded, and it was from a pair of Revolutions. Plus or minus 1.3 dB from 32 Hz to 10 kHz in an actual room, using 1/3 octave pink noise. Yup, re-read that. Very few speakers can pull that off in an anechoic chamber, let alone a real room! The point is, there are unorthodox techniques that offer significantly better real-world performance by seriously addressing the speaker/room interface. I tip my hat to Jorma Salmi for his brilliant design.

The secret to the Revolutions is dipole bass loading, which very significantly reduces the amount of reverberant bass energy put out into the room's resonant modes, along with cardioid radiation patterns for the mid/tweet modules. These unorthodox radiation patterns minimize the room's influence on the sound. The net result is a speaker that not only sounds very good, but does so in a normal (i.e. crappy) room.