[linux-audio-user] Re: Digital Fidelity

> Message: 5
> Date: Sun, 26 Feb 2006 21:46:23 -0800
> From: "Maluvia" <terakuma@email-addr-hidden>

> If there is one correct way to do this, then there should be no reason for
> different 'noise-shaping' algorithms.
> In fact, why are there different noise-shaping algorithms if the noise
> can't be heard.?

Mostly for going to 16bit CD quality from 24bit masters. It is possible
to hear dither noise at 16bit in pathological conditions.

It's possible to push the dither noise to parts of the spectrum where
it's less audible. Simple 1/2 lsb noise is perfectly adequate though.

>
> >> I can hear the distortion of the audio signal created by Dolby - and I
> >> don't like it.
> >
> >What has that to do with this discussion ?
>
> I merely mentioned that as another example of psychoacoustic masking that
> supposedly one cannot hear - yet I can.

Noise reduction bugged everyone. There was no other option with tape.

You say:
> I can also hear the difference between a digital copy and the original
> sound file, and between the same generation of digital copies on different
> hard drives.

And:
> We have an old Tascam portable 8-track, which is now ready for the junk
> heap, but we got close to perfect fidelity (after a lot of hard work) of
> what we recorded on it with respect to the live sound.
> If I wasn't looking, I couldn't tell if my husband was playing live, or
> playing back his recordings.

Those two statements..... Cmon, the tape hiss and funky eq should have
been a giveaway.

I think that what you are looking for is not fidelity but funk, vibe,
feel, whatever you want to call it... the way that tape can make a sound
be more like itself than the signal coming from the microphone.

I'm only pointing this out as it's so easy to get lost spending loads of
money chasing the highest precision lowest noise ultra wide band clean
recording, when that will not make things sound *good*.

Have you investigated dirtying the signal up a bit? No reason you cannot
lay the initial tracks down on the 8-track, and then transfer to Ardour
for overdubs etc. Or make stems from a digitally recorded Ardour version
and transfer them to tape for the final mix.

If you are not getting the sound you want with just digital, but got it
from tape, use the tape as an effect. In my experience, even quite
modest a/ds can capture the tape sound.

Other ways would be to try some of the tube/amp sim ladspa plugins, low
pass filters, using tape impulse responses with a convolver... be subtle
with them and you might be surprised.

Perhaps we should make a
linux.audio.user.boring.old.farts.who.think.they.know.everything mailing
list.
I would be happy to expound at even greater length on these topics if
there was such a list. :)

> Our early attempts to record that live sound through our Gina card directly
> to the hard-disk sounded just plain bad: harsh, strident, thin - cold, but
> more to the point - not at all like the live sound.
> The analog recordings have a warmth to them - a midrange 'fullness' that I
> don't hear digitally.

That's what tape does.

> Digital can sound very sterile.

Yup. That's the problem with precision.

> (When we attempted this through our earlier Pinnacle Multisound, it sounded
> like a midi guitar.)
>
> When we record now through our hdsp9632, the fidelity is very good - very
> clean (almost *too* clean), but still not quite the live sound - though
> very close.
> When I am unable to tell whether my husband is playing live, or playing
> back a digital recording of his music - then I will believe that the
> digital technology has matched analog.

This would be an interesting experiment....

Try setting your monitoring so you can switch between:
1: the direct microphone signal through your analog mixer.
2: the direct microphone signal though a single AD/DA conversion. (for
all intents the same as digital recording).
3: playback off tape.

I bet the difference between 1 and 2 will be very hard to hear, but the
difference between either of them and 3 will be obvious. You have to
balance the levels really carefully and not know which source is
selected to make it a fair comparison.

> If all it is going to take is a better quality AD converter - then I will
> be thrilled!
>
> >I know by now I've bored all the knowitalls here to tears, so I'll go
> >back to my corner now.
> >
> >--
> >Cheers, Gene
>
> Not at all, Gene, I enjoyed your comments.

Me too.

>
> >Dogma warning: You're not taking all the potential phenomena into
> >account that have not been scientifically explained yet.
> >
> >I'm not saying Maluvia can hear a difference, I'm just saying you don't
> >know that she can't.
>
> Thank you, Carlo. ;)

I'd agree with this as well. I just love discussing and practically
trying out all kinds of recording related things.

>
> - Maluvia
>
Received on Mon Feb 27 20:15:18 2006