Noob question about 7.1 subwoofer level

[thothsong]

I've configured my HDMI output for 7.1, going to an 11.1.4 soundbar+subwoofer+rears. In the 15-130Hz range, the SPL measurements I get measuring the sub (.1) channel are about 10 dB higher than what I measure on any of the other 7 channels. Which should I pay attention to when trying to balance levels? Or do I need to balance separately for stereo vs n.1 channel sound?

 

[Sonnie Parker]

10dB is very normal for most people. Mine runs 10-15dB depending on my preset and what I'm listening to.

The key is make sure you response is smooth and that the 10dB increase is not due to a single frequency area... like a 10dB peak centered at 100Hz.

 

[thothsong]

Thanks, but then for balancing sub level with the other speakers, should I compare the SPL level of the .1 channel with the low-mid-and-up range SPL level of the other channels, or compare the sub-bass-bass range SPL level of the other channels with the rest of their range?

 

[Sonnie Parker]

It's easier to see what's going on with a REW frequency response plot. Trying to balance the levels with an SPL meter only balances the highest frequency of each speaker and not really going to be accurate for the overall sound.

 

[thothsong]

Right, I'm not using an SPL meter. Here's a plot showing Left (channel 1) and Sub (channel 4). The response up to about 130Hz is very similar, just offset. I don't understand why that should be the case.

 

[Sonnie Parker]

This is normal... the sub will measure about 10dB higher when it is measured by itself.

For level adjustment... measure them both together, which is this case you'll probably want more bass.

Here is what we are listening to here today. Notice the approximate 8dB rise from 20kHz down to 20Hz. Albeit, this is main speaker with no sub at this time.

 

[thothsong]

OK, thanks very much.