#### Mr Wolf

##### Well-known Member

Not long ago I read this SVS article that explains how room gain works.

What is Subwoofer Room Gain

So, according to SVS, room gain starts at a frequency that is twice the wavelength of the longest dimension of the room which is almost always its length. For every octave below that starting frequency you should get 7-9dB of room gain which adds to the in-room SPL output of the sub. So the smaller the room and the lower the frequency the more room gain you should get. This gain is separate to boundary gain you get from corner loading.

Anyway, I used this logic to create this ready reckoner table that can be used by anyone in any room. The table assumes a 8dB per octave (i.e. mid-point of 7-9dB) so the actual result may vary +/- a few dB.

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So to use this table, take the longest dimension of your room and find the closest one to it in the left hand column. The numbers in that row represent the estimated room gain dB you may get at different frequencies. The table has the same frequency points as CEA-2010 output testing so you can use them to see how room gain can flatten out the measured CEA-2010 maximum SPL output of a particular sub.

As an example, this is how it impacts the output figures for one of my PB-3000 subs in my circa. 5.5M long room (highlighted in blue in the table) .

Anyway, hopefully you may find this useful when evaluating your next sub purchase decision.

What is Subwoofer Room Gain

So, according to SVS, room gain starts at a frequency that is twice the wavelength of the longest dimension of the room which is almost always its length. For every octave below that starting frequency you should get 7-9dB of room gain which adds to the in-room SPL output of the sub. So the smaller the room and the lower the frequency the more room gain you should get. This gain is separate to boundary gain you get from corner loading.

Anyway, I used this logic to create this ready reckoner table that can be used by anyone in any room. The table assumes a 8dB per octave (i.e. mid-point of 7-9dB) so the actual result may vary +/- a few dB.

So to use this table, take the longest dimension of your room and find the closest one to it in the left hand column. The numbers in that row represent the estimated room gain dB you may get at different frequencies. The table has the same frequency points as CEA-2010 output testing so you can use them to see how room gain can flatten out the measured CEA-2010 maximum SPL output of a particular sub.

As an example, this is how it impacts the output figures for one of my PB-3000 subs in my circa. 5.5M long room (highlighted in blue in the table) .

Anyway, hopefully you may find this useful when evaluating your next sub purchase decision.

Last edited: Aug 16, 2021