Re: [linux-audio-user] Re: Companies Refusing to Release/Permit Linux Drivers

On Sunday 26 February 2006 19:08, Maluvia wrote:
>>Because no converter can reach even the 24bit resolution. In fact the
>> best
>>
>>resolution you can reach is about 21 bits and the rest three bit
>> contains only a random thermal noise.
>>
>>regards,
>>Ctirad
>
>I did not know that - but am not really surprised.
>
>>There are not any true 24bit a/d converters yet.
>>There are not even any true 22 bit a/d converters, perhaps in some
>> labs.
>>
>>I think the best converters in the world manage about 20bit. (120db
>>dynamic range.)
>>
>>If a converter had a 24bit dynamic range (144db) and full scale was
>>+7db, then it would have to be able to resolve differences of 10
>>nano-volts (10 one billionths of a volt). That's perhaps possible
>> with cryogenics. Remember each extra bit *doubles* the dynamic
>> range!
>>
>>Real 24 bit recording should resolve from below the brownian noise
>> floor of air molecules hitting your ear drums to beyond the
>> threshold of pain.
>>
>>That's why we are stuck at 24bit
>
>Well thank you for a scientific explanation of this ceiling.
>I guess, then, that *real* 24-bit resolution, or something very close
> to it, would yield what I am looking for - if it can be achieved.
>
>>Recording is about creating illusions, not fidelity. If you record an
>>acoustic guitar in a totally dead room with the flattest most
>> accurate mic and pre, in to best a/ds in the world, it sounds... ok.
>>Put some reverb and top end on it, a little compression, perhaps add
>> a little distortion with an aural exiter, or recording to tape, and
>> people will say 'wow, what an amazing fidelity guitar recording!' :)
>
>I agree with this to a certain extent, but the quality of the effects
> - or the final signal after the effects are added, is affected by the
> fidelity of the original signal.
>There is a huge difference in our guitar sound put through an 8-bit
> Zoom processer, an 18-bit Alesis Q2, a 20-bit Alesis Q20, and a
> Behringer "24"-bit V-Verb.
>I think it is about both - using a high-fidelity acoustic signal
> blended with creative, high-quality effects to create a beautiful
> auditory experience.
>
>>Bullshit. If you can hear the difference between a 20 bit converter
>>and a >20 bit one, what you hear is the difference between two
>>converters, regardless of the number of bits they use.
>
>And you can prove this?
>I would assume, that if "24-bit" converters are really only 20-21
> bits, then a so-called "20-bit" converter is likely <<20 bit.
>I maintain that I *can* hear bit-depth difference.
>Are you perhaps suggesting that there exists some bit-depth threshold
> w/re to human hearing?
>What do you base your comment on?
>
>>Even 16 bits correctly dithered is better than 24 tracks on a 2 inch
>> tape.
>
>Again, what do you base this on?
>Recording what?
>
>"Correctly dithered" - and you would maintain that there is some
> objective standard as to what constitutes this?
>I can hear the distortion of the audio signal created by dithering,
> just as I can hear the distortion of the audio signal created by
> Dolby - and I don't like it.
>
>If you think existing digital technology can already match or exceed
> the audio fidelity of a 24-track reel-to-reel recorder, I would very
> much like to know what it is, and where it is available - and I would
> like to hear it.
>
>-Maluvia

Now thoroughly off topic, but what the hell...

Existing digital technology quite handily exceeds the performance of any
one track, or all 24 in parallel, in that 24 track recorder. Analog
recordings best snr would be around 70db, and thats only done on very
expensive tape formulations, the rest will be around 66db just from the
hiss of the individual particles of the meduim going by. Run the tape
fast enough and you'll move the majority of that spectrum into the
ultrasonic ranges, essentially beyond the *average* ears detectability
range. 15 ips helps, 30 is even better and at one point 60 ips was
being mentioned but I've never had the pleasure of hearing those
myself. 30 I have many times, and I thought it was very good indeed.

One final note, most of the tape used on 2" 24 track machines was
actually made for use as video tape in the quadruplex format, so the
grain orientation for best performance wasn't lengthwise for good
audio, and frankly it sucked at audio, but for the cross tape video
tracks made by the video head as it spun at 14,400 rpms while the tape
moved at 7.5 ips, or for really old first generation stuff, 15 ips.

As for digital versions of that, then the range of the a/d itself
becomes the limit, same as the file itself, and doubtfull it will
exceed 20 bits on an everyday basis. This is 50 to 70db better than
tape, so we may as well get used to it.

I submit that the perceived 'superior' perfomance of good analog tape
recorders, of any track width, is more a long term ear training result
than anything else, after all, we have been listening to such
machinery, faithfully encoded even on our cd's, and before that on our
lp records of yesteryear, for 3 or 4 generations now. Do that for 55
years, and the ear thinks thats what its supposed to sound like,
effectively becoming its 'Gold Standard'. The single exception to that
I can recall would be the panasonic Technics RS-1500, I swear that
machine could burn a track so hard you could see it on the back side of
the tape. It rather handily could record 12 to 14 db louder a signal
on the tape than any other deck I ever tangled with and stay below 2%
distortion doing it. A phenominal machine for its time back in about
1980ish.

Note that with the advent of digital recording, this use of analog tape
as the intermediate storage medium is being used less and less all the
time, so the distortion & noise artifacts of the tape are slowly
disappearing. I sometime wonder if little niggly itches some get about
the sound of so-and-so's newest albun isn't somehow related to this
even if the cd is only 16 bit as the difference can easily be heard
even at 16 bits.

That diff of tape or no tape isn't always that obvious, and I had that
hammered into me one evening in about 1961 when I had a chance to
listen to one of Emory Cooks 78 rpm lp's that had been recorded in
trinidad, live to disk, of some of their then infamous steel drum
bands. No tape in the path, straight from Altec M21 mics thru the
preamps & to the cutter head making the master.

The hair stood up on the back of my neck, it was that real. There was
stuff from the background crickets at 17khz or more that was as live
and real as if I had been standing in the middle of those crickets
myself. Even the whispers of the drummers as they kept each other in
step, probably 55db below the drums, could be heard well enough to
understand it if they were using english, which some didn't.

It was then I also appreciated that both the turntable playing that
record, and the turntable that cut it, were the then famous Fairchild
Battleships. With properly mounted motors and arms, those things can
dissappear into what can only be described as seismic noises. Very
very difficult to hear on speakers that don't do well below 15hz.

It was then that I really did understand that good audio performance by
ones equipment was always judged to be good more because the rig was
built or bought to suit the owner, than in the last nuance the current
craze for oxygen free speaker cables (thats all sales dweeb speak
folks) can ever make. As long as you get the best your budget allows,
you WILL think its the best ever, or will have plans to replace what
you perceive is the weakest link and then it WILL be the best.

And DO break the budget if you ever come across one of Cooks 78 rpm lp's
still in playable condition after all these years. Use a fresh,
0.3x0.7 thousanths eliptical tipped diamond needle, set at about 3/4
gram, in a Shure V-15 cartridge in a good arm and on a good turntable,
sit back and enjoy the acoustic experience of a lifetime. But clean it
first, with dish soap and warm water, and a velvet pad to remove as
much of the decades of grime you can from the grooves, then rinse well
with distilled water so you don't leave its minerals behind as it
dries. Don't play it first as that will just further embed the grit
into the plastic. They are priceless recordings of yesterdays
excellence, please treat them with the respect they deserve.

The material he recorded can best be described as eclectic, he even did
earthquakes, but did use tape for that so he could speed them up for
playback. Sounded a lot like thunder except the big clap wasn't always
at the start of the sound.

I know by now I've bored all the knowitalls here to tears, so I'll go
back to my corner now.

-- 
Cheers, Gene
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Copyright 2006 by Maurice Eugene Heskett, all rights reserved.