[comp.sys.next] Recording from CD

erik@zeus.opt-sci.arizona.edu (Erik Schumacher) (05/01/91)

I would like to put some songs from CD on my next.  Can I just connect my
CD player to the microphone input, or what do I have to do?  

Erik Schumacher
Optical Sciences Center
UofA
erik@zeus.opt-sci.arizona.edu

timbuck@wookumz.gnu.ai.mit.edu (Timothy Buck) (05/01/91)

In article <ERIK.91Apr30190902@zeus.penny.telcom.arizona.edu> erik@zeus.opt-sci.arizona.edu (Erik Schumacher) writes:
>I would like to put some songs from CD on my next.  Can I just connect my
>CD player to the microphone input, or what do I have to do?  
>
>Erik Schumacher
>Optical Sciences Center
>UofA
>erik@zeus.opt-sci.arizona.edu

No, it's not just a matter of connecting your CD player to the mike input...
The microphone jack on the NeXT monochrome monitor is apparently mono rather
than stereo.  You need a stereo to mono adapter (I haven't gone to look for
one yet).  Please let me know if you have any success.

The experience I've had that leads me to believe the mike input is mono went
as follows:
     I got a cable that runs two RCA plugs into one mini phone plug. 
     When I connected the RCA plugs to my CD player's output and plugged
     the other end into the NeXT microphone jack and tried to record,
     the recording level was extremely high.  I tried the right only and
     the recording level was fine, but of course the sound only came out
     of the NeXT's right speaker.  Left only (where the stereo signal is
     carried) gave the same results as both left and right.

Tim Buck     <>     timbuck@gnu.ai.mit.edu, timbuck@vtvm1.cc.vt.edu, or
                    jbuck@vtssi.vt.edu

goose@surf.sics.bu.oz.au (Ralph Schwarten) (05/01/91)

From article <ERIK.91Apr30190902@zeus.penny.telcom.arizona.edu>, by erik@zeus.opt-sci.arizona.edu (Erik Schumacher):
> I would like to put some songs from CD on my next.  Can I just connect my
> CD player to the microphone input, or what do I have to do?  

	Me Too ! I have had no end of trouble with cables etc
	The Problem seems to be that you need to be able to control
	output levels from the cd  Please respond to the net

> Erik Schumacher
> Optical Sciences Center
> UofA
> erik@zeus.opt-sci.arizona.edu





Ralph Schwarten
Bond Uni
Aus

wb1j+@andrew.cmu.edu (William M. Bumgarner) (05/01/91)

Microphone Jack:
  - 8 kHz mono, 8 bit codec encoded sound.  It is DESIGNED for voice
recording (about the same bandwidth as a telephone), and is basically
unacceptable for CD recording.

If you want to record CD quality sound, you need something like Digital
Ears or Digital Microphone that record at 16 bit/44kHz stereo....

Or you could hack a serial cable from the digital out of your CD player
to the DSP and write some DSP assembly to convert between the CD out
format to a .snd format.... (anyone done this?)

b.bum


b.bumgarner            | Disclaimer:  All opinions expressed are my own.
wb1j+@andrew.cmu.edu   | I officially don't represent anyone unless I
NeXT Campus Consultant | explicity say I am doing so. So there. <Thpppt!>
"I ride tandem with the random/Things don't run the way I planned them.."

zazula@uazhe0.physics.arizona.edu (RALPH ZAZULA) (05/01/91)

In article <1509@surf.sics.bu.oz.au>, goose@surf.sics.bu.oz.au (Ralph Schwarten) writes...
>From article <ERIK.91Apr30190902@zeus.penny.telcom.arizona.edu>, by erik@zeus.opt-sci.arizona.edu (Erik Schumacher):
>> I would like to put some songs from CD on my next.  Can I just connect my
>> CD player to the microphone input, or what do I have to do?  
> 
>	Me Too ! I have had no end of trouble with cables etc
>	The Problem seems to be that you need to be able to control
>	output levels from the cd  Please respond to the net
> 
>> Erik Schumacher
>> Optical Sciences Center
>> UofA
>> erik@zeus.opt-sci.arizona.edu
> 
> 
>Ralph Schwarten
>Bond Uni
>Aus

My CD player has a headphone jack that has a volume control.  Setting it
at the lowest level creates an output that the NeXT mic. can handle.  If
you don't have a headphone jack with a volume control, use the headphone
jack from your stereo (if you have one).  Also, try to keep the wires away
from the monitor as much as possible.  It is a great source of noise (I
use it to dirty up signals to try out filtering algorithms...).

Ralph

   |----------------------------------------------------------------------|
   | Ralph Zazula                               "Computer Addict!"        |
   | University of Arizona                 ---  Department of Physics     |
   |   UAZHEP::ZAZULA                            (DecNet/HEPNet)          |
   |   zazula@uazhe0.physics.arizona.edu         (Internet)               |
   |----------------------------------------------------------------------|
   |   "You can twist perceptions, reality won't budge."  - Neil Peart    |
   |----------------------------------------------------------------------|

brownd@agnes.acc.stolaf.edu (David H. Brown) (05/03/91)

In article <1509@surf.sics.bu.oz.au> goose@surf.sics.bu.oz.au (Ralph Schwarten) writes:
>[...]
>	The Problem seems to be that you need to be able to control
>	output levels from the cd  Please respond to the net
>Ralph Schwarten
>Bond Uni
>Aus

	Problems of sound quality (8-bit 8KHz CoDec vs 16-bit 44.1KHz CD)
aside, the CoDec does not provide input signal level control. And CD players
often give an unusually "hot" signal, with peaks at around 2VAC p-p;
microphones are invariably much lower. This will result in digital distortion
in a very unpleasant manner (what digital distortion isn't?).

If you wish, you may construct an varible voltage divider from parts commonly
available (say, at a Radio Shack.) In summary, take a variable potentiometer
(resistor) with three pins. For connectors, you'll need a 1/8" mini-phone
plug (into the CoDec input) and an RCA (phono) plug for the CD player--
perhaps two of these for L & R. Wire the center pin of the potentiometer to
the pin of the 1/8" plug. Wire one side pin of the potentiometer to the pin(s)
of the RCA plug(s). The remaining connections are all ground; they should be
connected together: RCA shields (rings), 1/8" sleeve, and the remaining pin
of the potentiometer.

If the volume control seems to work "backwards," either
switch the two side leads on the potentiometer, or live with it and when
anybody asks, just smugly explain that it isn't a volume control... it's an
attenuator, and you're actually increasing the attenuation, not raising the
volume! Either way, it will work.

Email me if you want more information... this is rather terse if you've not
done anything like this before.

Oh, yeah... the potentiometer should be about 100 K-ohms, audio taper if you
can find it, but linear taper is OK, too.

David H. Brown-- Music Department Student Network Representative
brownd@agnes.acc.stolaf.edu	663-2203; office (MWF A.M.) x3363

mig@cunixb.cc.columbia.edu (Meir) (05/04/91)

In article <1991May1.092359.576@arizona.edu> zazula@uazhe0.physics.arizona.edu writes:
>In article <1509@surf.sics.bu.oz.au>, goose@surf.sics.bu.oz.au (Ralph Schwarten) writes...
>>From article <ERIK.91Apr30190902@zeus.penny.telcom.arizona.edu>, by erik@zeus.opt-sci.arizona.edu (Erik Schumacher):
>>> I would like to put some songs from CD on my next.  Can I just connect my
>>> CD player to the microphone input, or what do I have to do?  
>> 
>>	Me Too ! I have had no end of trouble with cables etc
>>	The Problem seems to be that you need to be able to control
>>	output levels from the cd  Please respond to the net
>> 
>My CD player has a headphone jack that has a volume control.  Setting it
>at the lowest level creates an output that the NeXT mic. can handle.  If
>you don't have a headphone jack with a volume control, use the headphone
>jack from your stereo (if you have one).  Also, try to keep the wires away
>from the monitor as much as possible.  It is a great source of noise (I
>use it to dirty up signals to try out filtering algorithms...).

Or you could just buy an attenuating adapter from Radio Shack for $2.

 * * * * * * *  ======================= Meir Green                 
* * * * * * * * ======================= mig@cunixb.cc.columbia.edu 
 * * * * * * *  ======================= N2JPG