From Brian Willoughby Sent Thu, Mar 14th 2019, 07:14
From Brian Willoughby Sent Thu, Mar 14th 2019, 07:14
This indeed interesting, but the numbers you quote won=92t translate to = everyone=92s system. When you say -12 dB to -18 dB, I assume that you mean dBFS, as in dB = referenced to digital Full Scale. The trouble is that this will be different for every A/D converter, even = for folks using Protools. My A/D converter has literally hundreds of = input trim settings for analog signal levels all the way from faint = ribbon microphones to +26 dBu mixer outputs. At one end of that range, = anything above +6 dBu would distort, but changing the trim allows for = hotter signals without distortion. In other words, there are many = different signals that would measure -18 dBFS on my converter, depending = upon the trim. When you say that you bring the signal down, I have no idea how you=92re = attenuating the signal, whether that's in the A/D or before it, or where = in the signal chain your dBFS selects to meter. It=92s very likely that a different A/D would not distort until the = input meters read 0 dBFS. Laurie asked about an important factor, the = potential for distortion within the CS80 itself. I got the impression = that you=92ve ruled this out. Rob suggested that it could be a DC = offset, which is a good hunch, but it still hints that your metering is = not accurate. One good test would be to look at the actual waveform = being recorded. Better yet, upload an example WAVE file. My question to everyone is this: What analog signal levels does the CS80 = put out? Is it measured in dBu, on the professional +4 dBu scale? It = might be difficult to confirm the levels, though, except with a = calibrated oscilloscope or one of the many AP audio analyzers from Audio = Precision. Brian p.s. It=92s also possible that your A/D has been damaged. I do a lot of = live recording, and somewhere along the way someone turned on phantom = power when my MOTU 896HD was attached to the XLR inputs of their mixer. = This fried output channels 5 and 6, until I went inside and replaced the = op-amp. While I was in there, I put in protection for phantom power (and = then suggested to MOTU that they consider it for future products). I = didn=92t know about the problem until I was in a friend=92s studio and = heard distortion on just two of the eight channels. Granted, you=92re = dealing with input channels, but there could be something besides the = CS80 causing problems. What A/D hardware are you using? On Mar 12, 2019, at 7:45 AM, RJ Krohn <xxxxxxxxxxxxxxxxxx@xxxxxxx.xxx> = wrote: > I noticed recently that a CS80 will do a thing in the digital = recording domain that's fairly rare: the audio will distort well below = the redline threshold, depending on the patch. I will often run signal = at -12Db to -18Db in a Protools session. Most of the patches in the = machine will distort somewhere in this range; I often have to bring = signal path down below that -18Db threshold to get a clean audio signal. = I'm sharing because I realized this is about as close to an empirical = affirmation of what many folks hear with their ears: a described = "richness". So there's your useless synth nerd fact for the day. As you = were-R >=20