I have a P12 module thats exhibiting some odd behavior. I noticed the other day while playing it that some voices sounded noticeably lower in volume than others. So after investigating this further I decided to do some tests.
I had the unit on for several hours so I reset globals, cleared the filter calibration, and ran it again fresh. Then I initiated a basic patch, which is just a sine wave with no other processing going on, full gain, with wave rest so the sines all start at the same phase. Then I just recorded a sequence of 24 quarter notes at C3 (about 130.8 Hz), that way all the voices would cycle through twice. What I saw was the amplitudes of each voice fluctuate in a range of about +/- 3db. The pattern was the same for the first 12 notes as the last 12. Also I was sequencing this from my DAW, no velocity differences, no plugins, just the P12 straight into a line in on my MOTU interface.
I then read in the manual in the troubleshooting section that difference in the level of the voices could be due to the voice spread panning the voices in the stereo field, but I verified that this was set to zero. Furthermore, I recorded the left and right channels separately, and they all shared the same pattern of amplitude fluctuations. I also did the test again using C7 (about 2093 Hz) and while the amplitudes were still not all the same, this time they were different by about +/- 2db from each other.
So my thoughts are that in the oscillator section the amplitudes of the voices should all be pretty darn close to the same, unless of course you've got some processing going on that makes them different on purpose. But thats not so with the basic patch. One sine wave full amplitude, filters open, gain all the way up, no effects, no distortion, etc... So what I am thinking is that somewhere in the analog section, namely the filters and amplifier stages, these level differences arise.
Is this just normal analog synth behavior, or is this a sign my P12 is due for servicing? Its hard for me to tell. I wouldn't expect them to be bang on the same of course, but I would think they would be similar enough to not be noticeable.
Either way I am interested to hear what other P12 users experience. Thanks!