[Top] [All Lists]

Re: iRig pre

Subject: Re: iRig pre
From: "Max" oatcruncher
Date: Sat Nov 24, 2012 5:38 pm ((PST))
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:
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 =

--- 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

<Prev in Thread] Current Thread [Next in Thread>

The University of NSW School of Computer and Engineering takes no responsibility for the contents of this archive. It is purely a compilation of material sent by many people to the naturerecordists mailing list. It has not been checked for accuracy nor its content verified in any way. If you wish to get material removed from the archive or have other queries about the archive e-mail Andrew Taylor at this address: andrewt@cse.unsw.EDU.AU