Speaker Asylum

Posted by Richard BassNut Greene (A) on December 28, 2005 at 10:49:26

In Reply to: Wrong? posted by SteveB on December 28, 2005 at 04:44:53:

The small rooms that we use for audio sound different than large rooms for many reasons.

One of the biggest differences is the density of bass resonances in the important 40-80Hz. octave.

Each of the few resonances is likely to be heard as a bass boom or null because they are too far apart in frequency for our ears to smooth out (our ears have a 1/3 or 1/4 or 1/6 octave smoothing ability, depending on who you believe).

There are so many peaks and troughs above 200-300Hz. that our ears can not hear any one of them -- but under 80Hz. a frequency response peak or trough is too easy to hear.

This is about narrow bands of frequencies (typically 1/6 octave) where room reflections affect the bass frequency response too much.

If the peak SPL of a bass drum hit is supposed to be 90dB, but an in-phase bass reflection within the room makes the peak 95dB, then the listener will not hear what the musicians intended.

And a 95dB peak will take longer to fade to inaudibility (decay) than a 90dB peak.

The listener can get the correct dynamic peak of 90dB and faster room decay whether he uses bass traps or EQ.

Both are likely to sound better than doing nothing.

The "original signal" is irrelevant -- the signal that enters your ears is important.

In bass frequencies, the room often has a large and audible effect on the frequency response that makes the bass sound worse than it did when leaving the speakers (just listen to speakers outdoors for a more natural bass frequency response).