[Coco] Audio recording on CoCo

[gene heskett]

On Monday, November 21, 2011 12:31:59 AM Joel Ewy did opine:

> On 11/20/2011 09:57 PM, Brian G wrote:
> > I would like some advice on how to transfer LP music to CD.
> > What equipment, software is needed? I have a turntable that I have not
> > used in years, so starting from that, what do I need?
> 
> Computer with sound card.  Preamp to get the LP to line level audio.
> Cable from preamp to audio in jack on computer's sound card.  Some kind
> of recording software on the PC.  Audacity is Free / Open Source, and
> runs under Linux and I believe Windows and Mac.
 
You forgot what is probably the single most important item, the record 
turner, and the 'tone arm' and the cartridge mounted in it.  If a magnetic 
cartridge, you will need a preamp that converts the magnetic cartridges 
velocity mode output into an amplitude mode output, commonly call an RIAA 
preamp.

When records were king, there was no better playback cartridge than the 
Shure RE-15's, but the arm they were mounted in had to be capable of being 
adjusted to 1.5 grams tracking weight, and so friction free it would follow 
the recording groove faithfully at that pressure.  This cartridge had, as 
part of its elliptical diamond needle assembly, a carbon fiber brush that 
cleaned the record a few grooves in front of the needles position.  This 
brush partially supported the measured weight so that it used about 3/4 
gram and the needle the other 3/4 gram.  At that weight, record wear, even 
on the disk jockeys cue track area was/is non-existent.  The only problems 
I ever had in a broadcast studio setup that spun records about 18 hours a 
day was ham handed DJ's, who took a few hours getting used to an arm that 
to them, had mass but weighed nothing.  Amazingly, I was able to fix every 
needle they damaged.  Diamond needles usually have a 500-1000 hour 
lifetime, but these went at least 15,000 hours with no visible wear on the 
tip thru a 200x microscope.  If you can find an old manual Techniques 
turntable at a flea market that hasn't been mangled by a drunk, it is one 
of the quieter turntables sold in the last 30+ years.

Basically, to get a good digitization, you must start close to the top, 
there is no after the digitization treatment that can restore a rip made 
with a worn needle rattling around in the groove, not to mention its 5+ 
gram pressure is cutting the record.  One play is sufficient to change the 
sound of a record forever because of the groove damages some of the so-
called high quality cartridges of that day were in fact so stiff in their 
groove contact.  The Stanton D-500 laboratory standard cartridge was 
actually the worst offender and was sold by the thousands to all the mom & 
pop radio stations in the country.

When Olivia Newton John was getting "Physical", or Petula CLark was going 
"Downtown" we had to budget a fresh record about every 4 or 5 days so we 
were buying them in 5 packs.  After I changed the cartridges out for the 
Shure's, we never pulled another backup off the library shelf, they simply 
did not wear out.  Since those records were licensed for broadcast use, 
that was about the cost of those 2 cartridges, about $60/copy, that we were 
able to save out of the CODB column each week.

> With this you can digitize the audio and save it as a .wav file(s).
 
> You will then need some software to record these audio tracks on the CD
> in CDDA (CD Digital Audio) format.  On Windows, something like Nero
> Burning ROM would do the trick, or maybe something from Sonic.  Windows
> Media player might also be capable of doing this.  Under Linux try
> Brasero or Gnomebaker.  I'm not as familiar with CD authoring software
> for the Mac, but I think there's a program called Alcohol 100 Proof, or
> something like that.
> 
> I'm assuming you want to make a regular audio CD instead of burning a
> data CD with a bunch of .MP3 encoded audio files, for example.
> 
> > Second question. Is it _possible_ to save music files on the CoCo and
> > play them back and sound decent?
> > I would like to work on some software/hardware project on the Coco and
> > have the music play.
> > 
> >  Any ideas?
> 
> You'll need a sound digitizer program for the CoCo.  Oblique Triad put
> one out called Studio Works that may have ended up on some collection of
> disk images floating around the Internet.  You'll also need to make a
> cable that connects your audio source to the CoCo's joystick port where
> it will be sampled.
> 
> Another possibility, I think, is to use the 'play' program in OS-9 to
> play audio files digitized on a modern PC.  The CoCo's built-in hardware
> will only do monophonic sound at 6 bits of resolution.  If you have an
> Orchestra 90 cartridge, it can play 8-bit samples in stereo.  Of course
> the sample size is limited by the memory of the CoCo.  Not sure if
> 'play' can stream audio off a hard disk.  Not sure Drivewire or floppy
> disks could keep up with digitized audio.  That's about all I know about
> it.
> 
> JCE

Cheers, Gene
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