Accurate subwoofer calibration ?

[Vaughan Odendaa]

Hello all,

I am a little bit confused on this issue. I have always been under the impression that in order for the subwoofer to be calibrated accurately, with test tones, you would need 75 dB's. But since the SPL meter reads a little low, 72 dB would be the accurate setting.

Now I am hearing from the folks at AVS forum that the sub should be calibrated 4 dB's over the mains for an accurate calibration. This goes against what I have known for a long time and I need to know which is incorrect.

Which level is accurate ?

Thank you.

--Sincerely,

 

[MDS]

What rationale was given for calibrating 4 dB hot? My guess is personal preference.

The Radio Shack SPL meter is off on average 2-3 dB in the low frequencies so if you want it to match the other speakers, your first impression is correct - strive for 72 dB on the meter (this is assuming you are using the receiver's internal test tones which are at -30 dB).

In the end it won't matter much at all. The ear is extremely insensitive to small changes in amplitude at very low frequencies.

 

[Vaughan Odendaa]

Well, here is the link to the thread over at AVS forum :

http://www.avsforum.com/avs-vb/showthread.php?t=640252

I am posting there, asking questions. There is also an article in the thread that says the same thing. Dolby apparently recommends the same thing. I don't know. I'm really confused at this point.

I just wanted to talk to people here to find out what they think about it. Thanks.

--Sincerely,

 

[bpape]

If the meter is 2-3db down then you should calibrate that way for pure accuracy. Some people like it a little hot as a way to introduce a little 'house curve' without an EQ.

 

[Vaughan Odendaa]

Have you read through the thread ?

According to Tom Holminson and Dolby labs, the subwoofer level should be increased by 4 dB over the other main speakers.

I found this interesting because I've always operated under the assumption that in order for all main channels (and the LFE channel) to be evenly matched, you would set the SPL meter to read 75 dB.

Well, apparently, I was wrong all this time. It is actually 4 dB over the main channels for the LFE. Just thought I would share that with you.

--Sincerely,