Audyssey Calibration - Subwoofer Level

The directions for the Audyssey calibration on my Marantz SR5013 receiver say to set the subwoofer gain to 50% and the LPF to the highest setting. However, when I run the calibration routine, the sound from the sub is barely audible. I can't imagine the receiver can properly calibrate the subwoofer at such a low level. I could obviously turn up the gain (how would the receiver know the difference), but I'm wondering why it plays such a subtle calibration tone from the sub, when the tones played through the left/right/center are very loud. Anyone else experience this?

 

I've run Audyssey on 3 different devices and the subwoofer tones have always sounded very faint compared to the other speakers. So I think it's normal.

 

The auto calibration sound for my Velodyne is not as loud as I expected. I think there only needs to be enough volume for the mic to record the sound and find things like harmonic frequencies.

 

Thanks guys. An Audyssey technician replied to a message I sent late yesterday and said as long as the subwoofer level shown in the receiver menu is not +12dB, then the volume of the test signal was sufficient. In other words, if the subwoofer test tone was not sufficient, the receiver would boost the gain to the maximum (+12dB in my case), which would tell the user that the gain (on the subwoofer amp) needs to be turned up and the routine restarted. Anything below +12dB (something less than 0dB is ideal) shows that the gain level was within the proper range. The level shown for the subwoofer gain after I ran the setup was -6dB, which shows the gain on the subwoofer amp was sufficient.

 

If you're interested in a deep dive into subwoofer calibration, there's an interesting article here. The sentence most relevant to this discussion is

 

Interesting quote. That makes sense since part of what my sub is putting out I can't hear but I can feel it. I'll have to play with my external sound meter tonight and see if it can register sounds at those low frequencies.