On Fri, Jul 15, 2016 at 09:12:03PM -0400, jonetsu(a)teksavvy.com wrote: I don't find that number in the specs. But they do mention an EIN (Equivalent Input Noise) of -129 dBu(A), which is not bad at all (4 dB more than the theoretical minimum). Then if you use a dynamic mic, the result will depend on its sensitivity and impedance. Let's take the SM58 as an example: Impedance = 300 ohm. Sensitivity = 1.85 mV / Pa = -52.5 dBu at 94 dB SPL The impedance is twice the value used to measure EIN (150 ohm), so the effective EIN of the preamp when used with this mic could be a few dB higher. But let's ignore this. Then the equivalent acoustic noise level is -129 - -52.5 + 94 dB(A) = 17.5 dB(A). So if you are recording a sound with an SPL of say 70 dB, the S/N ratio of this signal will be 70 - 17.5 dB(A) = 52.5 dB(A). To this you need to add the effect of any EQ (which could go either way). Now is this OK or not ? It depends on loud this signal is reproduced. At the original level, the noise would be 17.5 dB(A). This you need to compare with the ambient noise level. You could gain a few dB by using a preamp with a lower EIN, but very few will be better. Or you could use a condenser mic with a lower self-noise. For example a Neumann KM184 has 13 dB(A), a TLM103 goes down to 7 dB(A), and you could gain 10 dB. With condenser mics, the self-noise of the mic will dominate the noise, unless the preamp is really bad. If you really have excessive noise, there could be some other reason. How did you combine the MPA and the 1010LT ? You should use a line input on the latter (using the +4 dBu and not the -10 dBV setting if you have the choice), and have all the gain in the MPA. P.S. if you want to do this sort of calculations, have a look at the slides of my Audio Measurements workshop: <http://kokkinizita.linuxaudio.org/papers/amworkshop1.pdf> Ciao, -- FA A world of exhaustive, reliable metadata would be an utopia. It's also a pipe-dream, founded on self-delusion, nerd hubris and hysterically inflated market opportunities. (Cory Doctorow)

"Probably setting the MPAII to +4 and using the ADC level in mudita24 to keep the 1010 from clipping will give best results, but it would not hurt to try -10 also with the ADC level higher. Let your ears and meters judge." There is no actual analog volume control on the 1010LT's RCA inputs, it's just doing multiplication on the captured signal after the ADC. If you are clipping the input turning the volume down in the software interface just gives you a scaled down version of the clipped signal. It is better to monitor the actual numbers coming off of the ADC chip. That way 0 dbFS on your meter in Ardour or whatever is actually 0dbFS at the ADC. In Envy24 control that means setting the 'analog volume' slider to 127, that's where you are actually seeing what's coming off the chip. Above that and the captured signal is being scaled up and below that the captured signal is being scaled down. Control your input level in the analog world before you hit the card. Shoot for peaks around -12dbFS. Also: there are jumpers on the card itself, you can use the XLR inputs as line level balanced ins. In my experience that's the best fidelity you can get with this card. (been using a 1010LT on Linux since 2006 or so...)

On Saturday, July 16, 2016 11:17:10 AM EDT Robert Edge wrote: What - did I read that right? This card definitely has analog volume input control. The 'Analog Volume' mixer tabs in Envy24 or Mudita24 control it. BTW About the jumpers that control input level: There are undocumented 'in-between' jumper settings for the input level. (The jumpers just switch various resistors in or out.) I discovered the settings and was forced to use them when the existing choices of levels were not quite enough for me. Tim.

On Sun, 17 Jul 2016, Tim E. Real wrote: Not having one, it is hard to be sure. I am pretty sure that the analog levels are sent to the ADC chip and are not done on the ice1712 itself. I know that the LT uses a cheaper ADC than the D66 which uses a cheaper chip than the D1010. Possibly the ADC itself does digital volume control, though this is not something I have seen in any of the chips I have looked at (not that I have looked at a lot). The more likely thing is that the clipping is happening in the analog ciruitry before the ADC. All of these cards take their voltages from PCI (+/- 12v - ish) That has to be dropped a bit to get anything like DC voltages through regulation. A +4 input does not peak at +4 but might peak as high as +27dBu (for the MPAII in question) which is about 50 v p-p... I would call that clipped with no pad in front of the gain stage. Note that the audible clipped peaks would generally not show on a dBu meter like that on the front of the MPAII. This why the LT has jumpers for the balanced inputs. So that the input level can be dropped to within the that +/- 12v range that the gain stage has to work with while still being able to be used as a mic input... using passive padding before the active stages get to it. -- Len Ovens www.ovenwerks.net

On Sun, 17 Jul 2016, Robert Edge wrote: How do you know this is digital and not analog clipping? The result would look the same. signal path: AC -> resitor -> buffer -> digitally -> ADC in pad on amp controlled card analog gain if the input signal after the input pad has p-p higher than amp's power rails allow, the signal will be squared off, just as you are seeing. The gain stage would be a part of the ADC chip BTW. The buffer amp is probably not, but rather a gain stage added to allow the use of mic level inputs. (M-Audio advertise it as a Mic Pre) -- Len Ovens www.ovenwerks.net

On Monday, July 18, 2016 10:30:47 AM EDT Robert Edge wrote: I already said that I did that and verified it works. Unless MAudio had started to make these cards without a volume control chip, your distortion is upstream, not from the 1010LT card. Or the card is not being used correctly. Check your settings. Are you sure the Patchbay/Router tab settings are correct? Or... your card has a partially fried preamplifier IC? Hey, it happens. This card has an ak4*** chip with full analog attenuator and amplifier. (And, uh... if /you/ don't believe /me/ then look at the 'About' tab in Mudita24 and see who one of the authors is.) But seriously, I hope this helps in better understanding the card and tracking down the real source of the distortion, which cannot be a properly functioning card. Tim.

On Sun, 17 Jul 2016 19:45:47 -0700 (PDT) Len Ovens &lt;len(a)ovenwerks.net&gt; wrote: Since then I got an ART Pro MPA II. Still getting (or starting to) with it. That device by itself makes noise, I find. First of all, there is a choice of +4db or -10dB I/O levels. Going through the 10101LT user guide, and assuming that the switches are at default (did not took the card out of the computer) which is -10db, the output of the MPA is then set at -10dB. Since the device itself makes noise, then the gain has to be brought loud enough to go over that noise, so that at room sound takes over, eg. room is made for the instrument. Using only one mic so far (AT2050 in cardiod mode) it is not possible to make the VU meter needles move with the playing but, the sound gets to Ardour all right. Since this is very early, I have certainly no conclusions thus far. Cheers.