RNP: Mics still pick up with gain turned down?

[George W.]

I noticed that when using the RNP direct to my soundcard with a mic
connected and the gain turned all the way down I still get some input
on the monitor levels in CEP. I can actually hear some input with
headphones, though it's fairly low. The level meters in CEP move along
pretty well though. It works this way on both channels and with all
mics. Is this normal or something to be concerned about?

Thanks.

[George W.]

On Wed, 12 Nov 2003 20:58:06 -0500, George W. wrote:

>I noticed that when using the RNP direct to my soundcard with a mic
>connected and the gain turned all the way down I still get some input
>on the monitor levels in CEP. I can actually hear some input with
>headphones, though it's fairly low. The level meters in CEP move along
>pretty well though. It works this way on both channels and with all
>mics. Is this normal or something to be concerned about?

I see that the Behringer 802 mixer does the same thing with the gain
turned all the way down, as long as the track and main levels are set
to "0". With the track and main levels turned hard left there's
nothing. So maybe it is a normal thing for a preamp with no actual
level control.......?

[Garthrr]

In article >, George W.
> writes:

>I noticed that when using the RNP direct to my soundcard with a mic
>connected and the gain turned all the way down I still get some input
>on the monitor levels in CEP. I can actually hear some input with
>headphones, though it's fairly low. The level meters in CEP move along
>pretty well though. It works this way on both channels and with all
>mics. Is this normal or something to be concerned about?

I dont think the lowest gain setting on the RNP is meant to be "off".

Garth~


"I think the fact that music can come up a wire is a miracle."
Ed Cherney

[Brian Takei]

George W. )
in article > wrote:
> I noticed that when using the RNP direct to my soundcard with a mic
> connected and the gain turned all the way down I still get some input
> on the monitor levels in CEP. I can actually hear some input with
> headphones, though it's fairly low. The level meters in CEP move along
> pretty well though. It works this way on both channels and with all
> mics. Is this normal or something to be concerned about?


Hi George. Yes, that's normal. When you plug a mic (or any source) into
a preamp (or any input), by definition there had better already be a
signal level, otherwise things will be pretty uneventful, because to
amplify a signal, you need a signal to amplify.

By design, the RNP does not attenuate (i.e. reduce the level of) the
signal. When the knob is all the way down/left/counter-clockwise, it is
at 'unity' gain, meaning that when the signal passes through this 'gain
stage', its level is intended to be unaltered (i.e. no gain or
reduction). So in your case, the source signal was already strong enough
on its own to bump the meters.

Depending on the device, a gain stage might be designed to also (or only)
provide attenuation (i.e. reduction) of the signal level. For example,
by design most EQ knobs set at 12:00 are at unity, and from there turning
it clockwise/up increases the signal, and turning it
counterclockwise/down decreases the signal. On the other hand, some EQ
units are 'cut only', meaning they only attenuate a band (thus 'all-the-
way-up' is the unity position).

Often/usually the unity position will be marked by a 0 or U, and other
positions numerically marked in +/- dB. Some gain stages might offer a
whole lot of attenuation, and the all-the-way-down position (i.e. maximum
attenuation) might for practical considerations be considered 'Off'.
This position might be marked with the 'negative infinity' sign.

Another example -- on a Mackie 1202 VLZ Pro's preamps, when the XLR mic
inputs are used, unity gain position is fully counter clockwise (like the
RNP). But when the 1/4" inputs are used on those same channels, unity
position of the knob is at about 10:00, and from there you can decrease
or increase the signal as needed. The point being that the unity
position is dependent on the device, and it's probably a good idea to at
least be aware of where unity is on the controls you are using, so you
know "which was is up", so to speak.

Another thing to be aware of -- if your signal source level is too high,
it can clip the input of a given device, and having the ability to
attenuate that signal past the input will be useless in correcting that
distortion. So in a situation where, say, you have a very sensitive mic
recording a loud instrument, and you're clipping the RNP's input, you can
easily correct that problem by inserting an attenuation 'pad' between the
mic and the RNP. Depending on what you record which what mics, you
probably don't need to worry about this, but it's something to be aware
of in the whole scheme of things.

Hope this helps,
- Brian

[Dan]

>
> I dont think the lowest gain setting on the RNP is meant to be "off".
>
> Garth~

I think you're right, its just the lowest gain.

[Kosmo Joe O]

And sometimes a hot signal (i.e. a loud snare) into a high output mic will
cause clipping on some mic-pre's with the gain at its lowest setting! This is
where pre mic-pre pads come in handy.
-Joe O

[George W.]

On Thu, 13 Nov 2003 06:21:01 GMT, Brian Takei wrote:

>George W. )
>in article > wrote:
>> I noticed that when using the RNP direct to my soundcard with a mic
>> connected and the gain turned all the way down I still get some input
>> on the monitor levels in CEP. I can actually hear some input with
>> headphones, though it's fairly low. The level meters in CEP move along
>> pretty well though. It works this way on both channels and with all
>> mics. Is this normal or something to be concerned about?
>
>
>Hi George. Yes, that's normal. When you plug a mic (or any source) into
>a preamp (or any input), by definition there had better already be a
>signal level, otherwise things will be pretty uneventful, because to
>amplify a signal, you need a signal to amplify.

<snip>

Brian,

Thanks so much for taking the time to explain all this so well. I
really appreciate all the help you and others have been passing on.

G.

[Kurt Albershardt]

Kosmo Joe O wrote:

> And sometimes a hot signal (i.e. a loud snare) into a high output mic will
> cause clipping on some mic-pre's with the gain at its lowest setting!

Most preamps have a minimum gain that is more than unity, BTW.

[Arny Krueger]

"Kosmo Joe O" > wrote in message


> And sometimes a hot signal (i.e. a loud snare) into a high output mic
> will cause clipping on some mic-pre's with the gain at its lowest
> setting! This is where pre mic-pre pads come in handy.

IME a common example of this would be Mackie XDR preamps on a SR32 console.
s you say, this makes a strong case for the use of in-line attenuators.
Generally, 10 dB does the job.

[Justin Ulysses Morse]

George W. > wrote:

> I noticed that when using the RNP direct to my soundcard with a mic
> connected and the gain turned all the way down I still get some input
> on the monitor levels in CEP. I can actually hear some input with
> headphones, though it's fairly low. The level meters in CEP move along
> pretty well though. It works this way on both channels and with all
> mics. Is this normal or something to be concerned about?


The RNP's gain control happens to go all the way down to "0" but it is
calibrated in decibels. Gain is a ratio (output to input) and decibels
are a logarithmic representation of that ratio. 0dB of gain is neither
an amplification nor attenuation. It is a gain of One, or unity. If
you hit the polarity switch, it would be a gain of -1.

0dB=20*log 1


ulysses