Hi,

In the software Control Panel for my sound card, the input level choices are +4db, Consumer and -10db. 

I have mine set to the -10db setting.  Seems like this should be the quietest, right?

I am not that familiar with the M Audio Delta 44, I have downloaded the manual. I see it is line input device mainly is that right. How do you connect low level sources such as microphones to the M Audio 44. I guess you are pre amping mic signals first is that correct?

If the M Audio 44 is a line level device only you should be getting virtually no noise at all either at the -10dBv or + 4dBu setting BTW the +4dBu is the less sensitive setting so in theory it should be the quietest of the two settings. (but it does depend on how they have configured that. They may not alter the gain of the first stage but pad the signal in front of it first in which case the noise level of the first gain stage will be the same.) You should be seeing very very low noise levels though coming from the M Audio.

The specs put the input dynamic range at 99 dB so I guess the noise must be at least that or lower.

Yes. I use outboard preamps. Grace 101 and Golden Age Pre73. 

OK Dave that is good. But you should be getting a much better noise floor than -80 dB though on your single track. It should be closer to -100 dB or so.

Can you setup Sonar to show you the incoming noise and try things like disconnecting the M Audio and the noise should drop well down to infinity then.  If after you disconnect the M Audio and the noise remains it means it is coming from somewhere else. 

I assume no plugins or anything inside Sonar as well.

Some possibilities:

- Turn off echo on all tracks so you are not getting noise from mics, mic channels, guitar pickups, or synths
- Better yet (or in addition), turn the track inputs off
- Make sure you don't have ground loops causing hum  (I think you would recognize that)
- Not needed if you are doing the above, but turn off synths that are close to your PC.  Some older ones will pick up or generate RF
 
You can also solo tracks one by one to make sure each is silent when the transport is stopped.

Once I heard a horrible amount of noise and realized I had 20 harmony tracks that were still echoing the same open mic—basically room noise x 20!  I had used the same mic and input to record the harmonies one by one.  Surely you are not doing something that goofy, but the open inputs and track echo can still be a problem.

I get the impression it might be something else rather than the suggestions that konradh has made (although they are always good things to check)

I get the feeling it may be possible that the M Audio may be noisy not sure. I would like to know what sort of noise results Dave is getting with nothing connected to his DAW. Also Dave do you have any other audio interfaces you could substitute to see if the noise levels drop etc.. Sonar won't be introducing noise that is for sure, in general DAW's don't do that, they are rather perfect in that regard. (more than I can say for reel to reel multitrack recording!)

Especially as the M Audio is basically a line level device, it really should be introducing no noise at all. I mean my interface (digital mixer) has the Mix Preamps built in and even when they are flat out max gained I am still only getting -108 dB of noise on a single track which is almost ridiculously quiet and that is a Mic Pre! 

I haven't seen an M-Audio card in many years but I think I remember that my old one had two choices of, shall we say, sensitivity: +4 and -10. I thought that the +4 was the "pro" setting, and since the rest of my setup wasn't pro level, I chose the -10. I recall something about that making it less likely I would cause clipping. But above, Dave said this: "the input level choices are +4db, Consumer and -10db." Does this mean three choices? +4, X, and -10? And which one is correct for him?

The input level sensitivity choice that is correct for him is simply based on what level the signal is that is feeding it. He says for example he is using a Mic Pre to feed into the M Audio. If the nominal output level of that Pre is +4 dBu then +4 dBu is the correct input setting.

On the other hand the word consumer only implies domestic hi fi gear for example. If he is feeding in say a CD player or something from a domestic Hi Fi setup then the signal leaving that device will be -10 dBv so that setting will be correct in that case.

Neither of these settings are responsible for the rather high noise floor that Dave is experiencing (I don't think anyway)

I use Grace 101 and Golden Age Pre73 pre's 99% of the time.

I spoke with Jim Roseberry (who built my DAW) this morning about the noise.

We ran a plug-in called RMS Buddy that measures the RMS level of a track or bus (as opposed to peaks) to see the overall level.  Handy plug!

RMS Buddy indicated an average noise floor of around -95db on a single channel input.

Jim said he would typically like to see this number closer to -105db.

He suggested that I look into any other devices/peripherals that I have in my recording set-up and see if I can track down anything that might be contributing noise.  A process of elimination.

He mentioned that audio interfaces that have their converters located "outside of the box" in contrast to ones like the Delta 44 (which is internal on a PCI card) tend to be quieter.

Bottomline was that he said the noise was not bad, however there is room for improvement.

I will continue to investigate and utilize some of the group's suggestions in my quest.

Thanks!