Originally Posted by whoaru99
Bearing in mind that 20V appears to be 20Vpp, but formerly discussed was Vrms. 20Vpp = 7Vrms.
Well that certainly clears things up. I was thinking there was no way this thing was cranking out 20v. 7 sounds much more likely. Thank you. That being said, the Onkyo does not show clipping at full tilt.
So in my other post when showing gain structure, my SMS1 is clipping the output signal at 1.77 volts not 5. Now what I'm not sure of is if this is an absolute value, or a value correlating to boost over incoming voltage via the volume knob.
Originally Posted by exojam
Just wondering here, if once you have finished setting the gain structure in the system, are you than going back and setting the individual speaker and sub levels with the internal test tone of receiver-processor? I just cannot see how you are getting such a difference in between the speakers and sub(s) once you have set up the gain.
Once again, the way I understand it; gain structure and calibrated level are two totally separate things.
I setup the gains as I should. I didn't use full boost on Onkyo as it's not required. Onkyo level was set to 0, I then opened the ep4000 gains to wide open and turned up the volume on the SMS1. I know the SMS clips the output at 28, so as long as I'm below that level I'm fine. Clip lights came on at volume 26, so I backed it down to 24.
So initial gain settings before any eq'ing were Onkyo 0, SMS1 at 24, and EP4000 wide open. Here's where I have the issue:
Both Audessey and the SMS see some major differences when calibrating at this point. And it makes perfect sense. Setting up a gain structure is not the same as calibrating output. When I went to EQ my SMS curve, at my gain structure level, there was no way to match the main level and sub level. I had the volume so far down on the receiver the mains sweep wasn't even registering. I had to turn the sub level to around -10, and raise the volume, to get the sub level and speaker level at around the same 80db level. So I know according to the ECM mic that the sub level was crazy hot at an output of 0.
Audyssey also confirms the same thing. When calibrating speakers, they are set around -2, and the sub level is set at -12; and this is with the gains on the 4000 backed down to about a 1/4 and the SMS volume at 13. When I turn them up any further, the sub level can't take enough out. Now I haven't verified this against an SPL meter as it's loaned out to a friend, but I trust that my SMS mic is pretty accurate and it's showing the same thing.So here's the nutshell. Assuming the SMS1 is boosting 1db per volume unit increase; I have a difference of 22 db's and 3/4 gain between gain structure setup and calibrated setup?????????????????????