Hi David,
Can you clarify what you mean by the input stage please; the iRig or the LS=
-10? In turn perhaps I should qualify what my intentions are. They are quit=
e simply to try and ascertain how quiet the iRig pre is. Having established=
some simple ground rules, as I've now done, the next stage is to record so=
me silence with various settings, both on the iRig and LS-10. It will be si=
milar to a previous experiment I did on here a while back, in conjunction w=
ith Rob Danielson, to determine the quality of the internal pre's on Fostex=
FR2 and FR2-LE, see here:
http://tech.groups.yahoo.com/group/naturerecordists/message/37962
One thing that has me slightly confused is, that on one side I see that Rai=
mund gives the quietest setting for the LS-10 at maximum gain on HIGH sense=
setting, and yet I'm sure I recall Vicky saying that in her opinion maximu=
m gain on LOW setting produced the best results? Admittedly there is only 1=
dbu between Raimund's max gain HIGH and LOW sense settings, so it's a mute =
point.
Cheers
Max
--- In "Avocet" <> wrote:
>
> > Set sense to Low and turn on to Record Pause; adjust gain on iRig.
>
> Max,
>
> Theory says that you should use a higher gain in the input stage
> provided it doesn't overload. You will have noise from the input stage
> whatever the level you set later, and for anything that follows,
> hopefully the later noise is swamped by the mic and input stage noise.
>
> However, theory should be backed up my experimentation, so it is worth
> doing a "family" of measurements. High frequency and low frequency
> input noises can also give different results. What is essentiul is to
> record a reference level from an acoustic input at your test settings
> to have something to compare the noise levels against. Find a sound
> source with a good range of frequencies that is repeatable like a food
> mixer in a kitchen and do the measurements at varying settings as you
> have been doing. Now you have something to compare your noise levels
> against.
>
> What makes noise levels difficult to compare is when their frequency
> plot varies. Hiss is normally the most distracting, so recording
> everything with a set bass cut can help. With a power spectrum, you
> can usually see bands of noise as well. Keep notes on every
> measurement. You can then reference the noises against the acousitc
> levels for each
> of your settings.
>
> Give yourself a good bit of leeway by recording low. You should find
> that digital recording noise s very low, but check that as well.
>
> I do hiss measurements with the mic under a pile of bedclothes. You
> still get rumble and a lot of domestic noises, but the acoustic hiss
> level should be low.
>
> You should also be able to recognise different types of noise. I wrote
> the other day about the fundamental noise which you should be able to
> hear on a mic with a good noise spec. Once you latch on to this
> particular noise, the goal is to hear it on every recording. :-)
>
> David
>
> David Brinicombe
> North Devon, UK
> Cogito cogito ergo cogito sum - Ambrose Bierce
>
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