decibels - what's it all about

Posted by: ARC on 03 February 2004

In an effort to understand the interaction between my room speakers and I have carried out some initial sound level measurements using a pair of B&W 601 speakers (usual speakers Shahinian Arcs) and ended up with:

40Hz 35db room center, 45db in corner
50Hz 58db room center, 70db in corner
63Hz 57db room center, 71db corner
80Hz 59db room center, 58 in corner.

What I'd like to know is for a 10db increase what is the actual sound impression i.e. is it twice as loud for that frequency?

Why measure in a corner? well I have a small room and that is my usual sitting position (or used to be anyway). I will be carrying out more measurements with the Shahinians soon and hope to be able to find a satisfactory speaker/listener position so avoid the need to change speakers.

Any comments about decibels appreciated.

Brendan

Posted on: 04 February 2004 by Fisbey

Strange how the lower frequencies have a higher reading in the corners, I'm sure I get the same in my room - more noticeable with the Arcs though...

Posted on: 04 February 2004 by Phill82

quote:
What I'd like to know is for a 10db increase what is the actual sound impression i.e. is it twice as loud for that frequency?

Yes, 10dB is generally considered to be percieved by the human ear as twice as loud.

quote:
Strange how the lower frequencies have a higher reading in the corners, I'm sure I get the same in my room - more noticeable with the Arcs though...

This is simply because of the nature of room modes which have high pressure at the boudary, and will have low pressure half way inbetween th two boundaries if it is a first orer mode.