ASIO4ALL level matching vs receiver

[gregw]

Hi all

When I use the pink noise generator in REW on individual channels in ASIO4all measuring the level with the SPL meter and Umik1, my subwoofer channel is 7 db higher then my mains. However, if I use the test tone generator in my Yamaha receiver, the sub channel is only about 2-3 db higher which is what I want. I thought the ASIO4ALL test would be more accurate since the YPAO might be causing a difference, but my Yamaha is an entry level receiver and I do not believe its YPAO applies any eq to the sub region (ie, when I run a sweep of the sub with YPAO on and off, the graphs are exactly the same).

Why is it that ASIO4ALL would have a big difference? Can I trust that the volume level it sends to each channel at -20db is truly the same? Could I have something set incorrectly? When I was trying to do sweeps with A4ALL, I was getting static but then I changed the buffer size and that has stopped.

The problem is I do not know which levels to trust. On some source material, the sub sounds a little too loud but on others not loud enough so it's very confusing. I really dont want to keep adjusting it based on what I am watching. would rather set it correctly once and then not think about it. Could the pink noise from the receiver for the sub channel not be including down to 20-30 Hz?

 

[John Mulcahy]

When you send signals directly to the LFE channel the processor adds 10 dB of gain, so you need to reduce the level by 10 dB.

 

[gregw]

I was starting to suspect something of this nature as I had read about differences in the LFE level vs other channels but what I had read had said that source material is programmed to have 10 db additional gain not that the processor adds 10 db gain. But glad to have a definitive explanation from the authority!
John I am new to the AV enthusiast space but I am mightily impressed with what you have brought to the community with REW and very appreciative of your efforts. Thanks!!