Re: [linux-audio-dev] Writing a driver for this card: your thoughts?

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Subject: Re: [linux-audio-dev] Writing a driver for this card: your thoughts?
From: Lamar Owen (lamar.owen_AT_wgcr.org)
Date: Wed May 29 2002 - 02:43:14 EEST


On Tuesday 28 May 2002 06:40 pm, Tim Orford wrote:
> On Tue, May 28, 2002 at 04:19:48PM -0400, Lamar Owen wrote:
> :-) bring on the flames :-)

This is a flame? Tempest in a teacup... :-)

> and good quality audio sounds better?
> this is a new one to me - i've never heard anyone
> blame it on the source material before....hmmm...:-)

Yes, actually, good quality source material sounds better. Orban's Optimod
9100 manual, circa 1987, mentions this as part of the setup instructions.

> I do sympathise with you, but if that much compression was
> desirable, then the tracks would be mixed like that in the first place.

Have you checked the dynamic range (or lack thereof) on some recent CD's?
They are compressed flat as a pancake.

But, like I said, for AM radio coverage area is directly proportional to
modulation percentage. FM radio doesn't have that excuse.

And I personally process the least I can get away with. But it does
compensate for much operator error in the lack of watching levels. And the
six band limiter of the Optimod 9100 is pretty clean.

> But like you said, it has been a big point of contention for a long
> time, and i dont think we will solve it here :-)

Yes, indeed.

> > Phase-linear balanced outputs won't cancel _any_ harmonics. Where did
> > that concept come from?

> i have seen this in balanced internal circuitry, for example
> in valve compressors. Its been a few years since i did much
> analogue stuff, so i'm gonna be deliberately vague here.

Certainly in a non-linear situation (such as a tube compressor, such as the
ever popular UREI leveling amplifier (got one)) balanced versus non-balanced
internal to the processing will change the transfer function. But this is an
I/O discussion.

> >And the Carver Silver Seven sounds better than the old
> > M400, too, right? :-) (audiophile humor)

> ok, i can see that you think that i am some kind of audiophile
> lunatic, which maybe i am to a certain extent. There have been
> several things which have changed my life in a major way in the
> last few years:

That wasn't my intention; my apologies.

> One was the discovery of the Free Software movement. One was the
> discovery of class A, low feedback design (thereby shattering
> most of what i was taught at college).

Class A design has it's strong points. As long as you are in a good linear
portion of the transconductance curve you're OK.

> I'm not really disagreeing with you, but i think my
> point was that there are more factors to take into
> account that you appeared to be ignoring.

There's always factors. In another forum I might detail how the assymetry of
tower base impedance creates distortion in the transmitted audio of an AM
station, and how silver plated coils and multi-thousand dollar vacuum
capacitors with computer modeled matching networks have more of a bearing on
my sound than the audio inside the studio. My matching network here is worth
over $75,000, thanks to the engineering behind it. And that's just so that
my 11khz sliver of audio passband will be as flat as possible. But that would
be a major digression. By private e-mail, perhaps.

>There is a lot
> more to analogue audio than just keeping impedances low,
> wacking up the negative feedback, and measuring the noise
> floor, as i'm sure you realise.

Certainly. Transmission line factors must be taken into account for long runs
at high frequencies, etc. Lots of factors. But the question I was answering
was a simple 'I've never heard of balanced drivers; what are they?'

> So to get back to the original point, i'm sure the cards
> you mentioned are indeed fine cards, but if cost is no object
> (ha ha!) and if quality is your objective, then you will put your
> analogue converters in a separate box with a dedicated power
> supply.

Those ASI cards ain't cheap. Check them out: audioscience.com.

-- 
Lamar Owen
WGCR Internet Radio
1 Peter 4:11


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