Reducing noise in digital recordings

[Bill Bremmer]

Hello,



I'm doing some voice production work at home for a local radio station.

Using Cool Edit along with M Audio's Mobile-Pre, a Pentium 3 computer, a
Shure PG-58 mic, Windows XP.



When everything is powered up and the mic is on, I'm showing a -54 dB
reading on my Cool Edit screen. I think that that is too noisy. Obviously,
I can just about eliminate any of this noise (hiss or system noise) by
using Cool Edit's Noise Reduction software after I have recorded, but no
matter what percentage of reduction I use, I will hear some artifacts.



On the Mobile Pre, the gain control is set at about 4 o'clock, six is about
maximum. The recorded wave form is showing peaks at about 30%. I then must
"normalize" the recording to 95-100% for the final recording. It seems that
I should be getting more mic gain from the pre-amp, so that I don't need to
set the output gain to 4 o'clock and then normalize in Cool Edit. I must use
about a 12 foot USB cable to connect the pre-amp to the computer, but I
don't think that this is much of a factor.



I would appreciate any thoughts you might have.



If I wanted to improve the sound quality, without spending a lot, what areas
do you think I could improve?



Thank you,

Bob K at .

[eric]

On Sat, 28 Jul 2007 15:21:48 -0400, Bill Bremmer, during a pipe dream
babbled:

> If I wanted to improve the sound quality, without spending a lot, what
> areas do you think I could improve?

How quiet is the room you are recording in? You may ne picking up ambient
noise.

--
Quis corriget ipsos correctores?

[Eeyore]

Bill Bremmer wrote:

> On the Mobile Pre, the gain control is set at about 4 o'clock, six is about
> maximum.

The spec on this is so useless that I can't tell how many dB of gain that is.

I suspect you simply need a quieter mic pre.


Graham

[Bill Bremmer]

If the problem is the pre-amp, would the noise be less noticable if the
pre-amp was sending a stronger signal to the computer? Is cranking up the
gain almost to full increasing the noise that might otherwise not occur with
a stronger signal from another pre-amp to the PC?


"Eeyore" > wrote in message
...
>
>
> Bill Bremmer wrote:
>
>> On the Mobile Pre, the gain control is set at about 4 o'clock, six is
>> about
>> maximum.
>
> The spec on this is so useless that I can't tell how many dB of gain that
> is.
>
> I suspect you simply need a quieter mic pre.
>
>
> Graham
>

[Arny Krueger]

"Bill Bremmer" > wrote in message

> Hello,
>
>
>
> I'm doing some voice production work at home for a local
> radio station.
> Using Cool Edit along with M Audio's Mobile-Pre, a
> Pentium 3 computer, a Shure PG-58 mic, Windows XP.

> When everything is powered up and the mic is on, I'm
> showing a -54 dB reading on my Cool Edit screen. I think
> that that is too noisy. Obviously, I can just about
> eliminate any of this noise (hiss or system noise) by
> using Cool Edit's Noise Reduction software after I have
> recorded, but no matter what percentage of reduction I
> use, I will hear some artifacts.

First we need to know the nature of the noise. It could easily be ambient
noise. You can check on that by simply using a long mic cable and moving the
mic to a quiet place much further away from the computer, burrying the mic
in a really big pillow, etc.

Can you post a MP3 file of the noise on one of those public access file
storage sites?


> On the Mobile Pre, the gain control is set at about 4
> o'clock, six is about maximum. The recorded wave form is
> showing peaks at about 30%. I then must "normalize" the
> recording to 95-100% for the final recording. It seems
> that I should be getting more mic gain from the pre-amp,
> so that I don't need to set the output gain to 4 o'clock
> and then normalize in Cool Edit.

The PG-58 is a dynamic mic, and its output is not going to be really high.
Move it closer to the source, it is designed for close working.

I must use about a 12
> foot USB cable to connect the pre-amp to the computer,
> but I don't think that this is much of a factor.

Agreed.

> If I wanted to improve the sound quality, without
> spending a lot, what areas do you think I could improve?

Get a condensor mic, they usually have far higher output.

[Eeyore]

Bill Bremmer wrote:

> "Eeyore" > wrote in message
> > Bill Bremmer wrote:
> >
> >> On the Mobile Pre, the gain control is set at about 4 o'clock, six is
> >> about maximum.
> >
> > The spec on this is so useless that I can't tell how many dB of gain that
> > is.
> >
> > I suspect you simply need a quieter mic pre.
>
> If the problem is the pre-amp, would the noise be less noticable if the
> pre-amp was sending a stronger signal to the computer?

Depends. But possibly, although the improvement is only likely to be marginal.


> Is cranking up the gain almost to full increasing the noise that might
> otherwise not occur with
> a stronger signal from another pre-amp to the PC?

Too many variables to give a meaningful answer. The spec on the 'Mobile Pre' is
so sketchy (it doesn't give one of the most critical noise figures that's the
industry norm - and is generally vague) that I suspect it may be a rather poor
performer, and part of your problem.

AND ! Do please type your answer HERE !

If you place your reply at the top one has to go backwards and forwards trying
to work out what you're replying to.

Graham