Emu XL-7 & MP-7 User's Group

I know that it is good recording practice to get the hottest signal 
from the source without clipping to get a good singal to noise 
ratio.  Is this required for SPDIF?  I am thinking that since the 
connection is digital I should be able to record from the MP-7 then 
normalize the recordings on my PC without boosting noise.  Does 
anyone have experience with this? It will save me a lot of time vs 
editing all presets and boosting the AMP VOL there.

Thanks,

Kris

Well, to be honest, the SPDIf signal from the XX-7's is actually pretty 
weak.  It's far below what it could be, so you'll be normalizing your 
recordings by a greater amount than if you were to just use the regular 
audio outs where you could send a hotter signal.  Anyway, yes in theory 
you should be able to normalize your digital signal without adding (or 
boosting I should say) any additional noisefloor artifacts.  BTW, why are 
you wanting to normalize them in the first place?

rEalm



I know that it is good recording practice to get the hottest signal 
from the source without clipping to get a good singal to noise 
ratio.  Is this required for SPDIF?  I am thinking that since the 
connection is digital I should be able to record from the MP-7 then 
normalize the recordings on my PC without boosting noise.  Does 
anyone have experience with this? It will save me a lot of time vs 
editing all presets and boosting the AMP VOL there.

Thanks,

Kris 



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I am using the MP-7 through a Tascam US-428 to Cubase
5.1.  I thought something was wrong with my setup at
first because the recordings had no waveform.  After
about 30 minutes of fiddling around I hit play and
heard that they actually did record.  I had to stretch
the display to its maximum track size just to see a
little bit of waveform.  Thats when I normalized the
recordings so that I could see the waveforms for
editing.  I did not notice any additional noise, but I
just wanted to see if anyone else has experience with
this.  If SPDIF does not have a noise floor I think
that it would be simpler and quicker to just normalize
everything on the PC rather than adjust each preset
manually to get a hot signal without clipping.  It
also saves preset slots for me since sometimes my only
modification is to increase AMP VOL.
--- erik_magrini@... wrote:
> Well, to be honest, the SPDIf signal from the XX-7's
> is actually pretty 
> weak.  It's far below what it could be, so you'll be
> normalizing your 
> recordings by a greater amount than if you were to
> just use the regular 
> audio outs where you could send a hotter signal. 
> Anyway, yes in theory 
> you should be able to normalize your digital signal
> without adding (or 
> boosting I should say) any additional noisefloor
> artifacts.  BTW, why are 
> you wanting to normalize them in the first place?
> 
> rEalm
> 
> 
> 
> I know that it is good recording practice to get the
> hottest signal 
> from the source without clipping to get a good
> singal to noise 
> ratio.  Is this required for SPDIF?  I am thinking
> that since the 
> connection is digital I should be able to record
> from the MP-7 then 
> normalize the recordings on my PC without boosting
> noise.  Does 
> anyone have experience with this? It will save me a
> lot of time vs 
> editing all presets and boosting the AMP VOL there.
> 
> Thanks,
> 
> Kris 
> 
> 
> 
> To unsubscribe from this group, send an email to:
> xl7-unsubscribe@yahoogroups.com
> 
>  
> 
> Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/ 
> 
> 
> 
> 
> 
> 
> 
> [Non-text portions of this message have been
> removed]
> 
> 


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> Anyway, yes in theory 
> you should be able to normalize your digital signal without adding (or 
> boosting I should say) any additional noisefloor artifacts.

How does that follow? If the digital audio signal comes across with a
noise floor, then boosting or normalising is going to raise the noise
level as well. If there's a noise floor in the XL-7 prior to analogue
output, then maximising the gain of the voices there is definitely
going to help.

-- 

  nick rothwell -- composition, systems, performance -- http://www.cassiel.com

--- kmusard <kmusard@...> wrote:
> I know that it is good recording practice to get the hottest signal 
> from the source without clipping to get a good singal to noise 
> ratio.  Is this required for SPDIF?  I am thinking that since the 
> connection is digital I should be able to record from the MP-7 then 
> normalize the recordings on my PC without boosting noise.

Well, you're correct in that you won't be boosting analog white noise
(as there is none in digital) but you will be boosting quantisation
noise.  However, as S/PIDF is at a much higher bit depth than most
media these days, you should be fine.  Normalizing the S/PDIF will
*always* yield quieter results than recording the analog mains because
the same digital signal that feeds the S/PDIF feeds the D/A converters
(don't quote me on that, but I'm pretty sure).  Therefore, all you're
doing by recording the analogs very hot is performing analog
normalization instead of diginal normalization, with unneeded D/A and
A/D stages!

-Aaron

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What does quantisation noise sound like?  How can I
recognize this?

--- Aaron Eppolito <synthesis77@...> wrote:
> --- kmusard <kmusard@...> wrote:
> > I know that it is good recording practice to get
> the hottest signal 
> > from the source without clipping to get a good
> singal to noise 
> > ratio.  Is this required for SPDIF?  I am thinking
> that since the 
> > connection is digital I should be able to record
> from the MP-7 then 
> > normalize the recordings on my PC without boosting
> noise.
> 
> Well, you're correct in that you won't be boosting
> analog white noise
> (as there is none in digital) but you will be
> boosting quantisation
> noise.  However, as S/PIDF is at a much higher bit
> depth than most
> media these days, you should be fine.  Normalizing
> the S/PDIF will
> *always* yield quieter results than recording the
> analog mains because
> the same digital signal that feeds the S/PDIF feeds
> the D/A converters
> (don't quote me on that, but I'm pretty sure). 
> Therefore, all you're
> doing by recording the analogs very hot is
> performing analog
> normalization instead of diginal normalization, with
> unneeded D/A and
> A/D stages!
> 
> -Aaron
> 
> __________________________________________________
> Do you Yahoo!?
> The New Yahoo! Search - Faster. Easier. Bingo
> http://search.yahoo.com
> 


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Ok well, the real problem isn't noise so much as that the overall sound quality
suffers because you have less dynamic range recorded in the bits.  So if you
normalize it it will work, and you may get quantization noize, however you won't
get the same amount of overall information on a weak spdif signal since you
effectively cut out more and more bits to hold frequency information. In a true
analog signal it extra frequency content even at low volumes.  The best way is
just to fix everything in the mix so you can get it as hot as possible for the
spdif.  The reason (and I am just guessing on this) the overall volume is lower
for the SPDIF on the XL7 is that you have such a wide range of dynamics,
especially when using filters so you have to make sure there is enough headroom
on the digital out for peaks like this.  On the analog converters they simply
overdrive or distort but even they can be made to digitally clip now and then.

Andre

-----Original Message-----
From: Kris Musard [mailto:kmusard@...]
Sent: Tuesday, April 22, 2003 12:49 PM
To: xl7@yahoogroups.com
Subject: Re: [xl7] recording from SPDIF output?


What does quantisation noise sound like?  How can I
recognize this?

--- Aaron Eppolito <synthesis77@...> wrote:
> --- kmusard <kmusard@...> wrote:
> > I know that it is good recording practice to get
> the hottest signal
> > from the source without clipping to get a good
> singal to noise
> > ratio.  Is this required for SPDIF?  I am thinking
> that since the
> > connection is digital I should be able to record
> from the MP-7 then
> > normalize the recordings on my PC without boosting
> noise.
>
> Well, you're correct in that you won't be boosting
> analog white noise
> (as there is none in digital) but you will be
> boosting quantisation
> noise.  However, as S/PIDF is at a much higher bit
> depth than most
> media these days, you should be fine.  Normalizing
> the S/PDIF will
> *always* yield quieter results than recording the
> analog mains because
> the same digital signal that feeds the S/PDIF feeds
> the D/A converters
> (don't quote me on that, but I'm pretty sure).
> Therefore, all you're
> doing by recording the analogs very hot is
> performing analog
> normalization instead of diginal normalization, with
> unneeded D/A and
> A/D stages!
>
> -Aaron
>
> __________________________________________________
> Do you Yahoo!?
> The New Yahoo! Search - Faster. Easier. Bingo
> http://search.yahoo.com
>


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Pretty much what I was trying to get at.  Also, if you can get a hotter 
signal via the analog outs you may not even have to normalize anyway.  I 
mean, if you're recording in the digital domain and the waveform is so low 
you can't even see it in your audio editor, chances are you're going to be 
normalizing quite a bit.  So ummm, I guess try both and see which sound 
better for you!

rEalm




Ok well, the real problem isn't noise so much as that the overall sound 
quality
suffers because you have less dynamic range recorded in the bits.



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