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  #1   Report Post  
Ben Nguyen
 
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Default How to separate 1 waveform composed of two tracks

I have a bad audio tape that contains both sides of the tape recording
on one side. So when played you can hear both sides at the same time
with one track backwards.

Sonic Foundry has a reverse feature but I cant separate the 2 sides so that
I can reverse just one (The audio clip shows up as just one waveform.)

Is there a way to filter the waveform into its 2 track components?

Help!
Ben
  #2   Report Post  
james
 
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Default How to separate 1 waveform composed of two tracks

In article ,
Ben Nguyen wrote:

I have a bad audio tape that contains both sides of the tape recording
on one side. So when played you can hear both sides at the same time
with one track backwards.


Have you considered adjusting the head geometry first? This sounds like
the sort of thing you should try to fix in the analog domain. Once
the green beans touch the mashed potatoes, the plate becomes toxic,
right?
  #3   Report Post  
W. Williams
 
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Default How to separate 1 waveform composed of two tracks


"Ben Nguyen" wrote:
I have a bad audio tape that contains both sides of the tape recording
on one side. So when played you can hear both sides at the same time
with one track backwards.


Are you sure that the problem does not lie with your playback equipment or
setup? It sounds like:
a) you have possibly recorded a half track recording on a full track machine
b) you have possibly set up your software to record in mono from a two track
source
c) your playback equipment is possibly hooked up incorrectly (I have seen
people familiar with a Nagra IV-2 hook up a IV-S incorrectly and without
realising and vice versa. I have also seen wiring fiascos where an
inexperienced person has joined up the left and right where they intended to
join the return.)
d) someone has accidentally recorded over pre-existing material without
erasing the original material.

Sonic Foundry has a reverse feature but I cant separate the 2 sides so

that
I can reverse just one (The audio clip shows up as just one waveform.)

Is there a way to filter the waveform into its 2 track components?


No, however I suspect your problem is either due to a, b or c above, all of
which can be remedied before going into the digital domain. In the event
that it is in fact due to d, then IME it is usually impossible to do
anything about it.

I have seen a few cases where a half-track field recording was made on a
poorly calibrated machine, in which case you need to manually re-calibrate
your playback equipment to recreate the calibration of the original
recorder.

W


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Richard Crowley
 
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Default How to separate 1 waveform composed of two tracks

"Ben Nguyen" wrote ...
I have a bad audio tape that contains both sides of the tape recording
on one side. So when played you can hear both sides at the same time
with one track backwards.


You are not playing it back with the same head configuration as it
was recorded with. There is no substitute for using the corresponding
geometry to play back the tape.

Sonic Foundry has a reverse feature but I cant separate the 2 sides so

that
I can reverse just one (The audio clip shows up as just one waveform.)


Once they have been mixed together (whether magneticaly, electically,
or acousticaly) there are really no practical methods of separating them.

Is there a way to filter the waveform into its 2 track components?


No. You must find a tape machine with the same head arrangement
(2-track, 4-track, whatever) as the tape was recorded with.


  #5   Report Post  
Richard Crowley
 
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Default How to separate 1 waveform composed of two tracks


"james" wrote in message
news:9w9ac.16452$Q45.13642@fed1read02...
In article ,
Ben Nguyen wrote:

I have a bad audio tape that contains both sides of the tape recording
on one side. So when played you can hear both sides at the same time
with one track backwards.


Have you considered adjusting the head geometry first? This sounds like
the sort of thing you should try to fix in the analog domain. Once
the green beans touch the mashed potatoes, the plate becomes toxic,
right?


No, this happens only with "creamed" vegetables (creamed
corn, creamed peas, etc.) eeeeewwwwww! :-)




  #6   Report Post  
Arny Krueger
 
Posts: n/a
Default How to separate 1 waveform composed of two tracks

Ben Nguyen wrote:

I have a bad audio tape that contains both sides of the tape recording
on one side. So when played you can hear both sides at the same time
with one track backwards.


Probably not a bad tape at all. Instead, you're playing the tape with the
wrong tape player.

For example, if you play a 4 track 1/4" wide tape with a two-track 1/4" tape
player, you'll get exactly the results you've described. Try using a true
4-track player.

The tracks on a 4-track 1/4" tape are interleaved. Track 1 & 3 as you go
down the tape are recorded one way. Tracks 2 & 3 are recorded the other way.
If you play this tape with a 2-track player, tracks 1 & 2 will be combined
by the wider tape head in the 2-track player. That will give you exactly the
symptoms you describe.




  #7   Report Post  
Scott Dorsey
 
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Default How to separate 1 waveform composed of two tracks

Ben Nguyen wrote:
I have a bad audio tape that contains both sides of the tape recording
on one side. So when played you can hear both sides at the same time
with one track backwards.


This was recorded on a machine with a misaligned head, I assume. What you
need is to play it back on a machine with a narrower than normal head.

If this is a half-track tape, you can put it on a quarter-track machine and
then move the head height adjustment up and down until you find a place where
it sounds good.

Sonic Foundry has a reverse feature but I cant separate the 2 sides so that
I can reverse just one (The audio clip shows up as just one waveform.)

Is there a way to filter the waveform into its 2 track components?


This is a physical problem with the tape. It needs to be fixed with proper
playback.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
  #9   Report Post  
William Sommerwerck
 
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Default How to separate 1 waveform composed of two tracks

I have a bad audio tape that contains both sides of the tape recording
on one side. So when played you can hear both sides at the same time
with one track backwards.


It's probably a fine tape. You're just playing it on the wrong
machine. There are several different track formats some of which will
play back like this when the playback heads don't line up with the
recorded tracks. That's where you need to solve the problem and it may
involve looking around for someone to either do the transfer for you
or, if you have a large number of tapes in that format, loan, rent, or
sell you the correct machine.


To put it a bit more directly... You're playing a half-track tape on a
full-track machine.

  #10   Report Post  
hank alrich
 
Posts: n/a
Default How to separate 1 waveform composed of two tracks

Scott Dorsey wrote:

Ben Nguyen wrote:
I have a bad audio tape that contains both sides of the tape recording
on one side. So when played you can hear both sides at the same time
with one track backwards.


This was recorded on a machine with a misaligned head, I assume. What you
need is to play it back on a machine with a narrower than normal head.


Or it's 1/4 track being played back on 1/2 track? Or mono 1/2 track on
fulltrack?

--
ha


  #11   Report Post  
Scott Dorsey
 
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Default How to separate 1 waveform composed of two tracks

hank alrich wrote:
Scott Dorsey wrote:

Ben Nguyen wrote:
I have a bad audio tape that contains both sides of the tape recording
on one side. So when played you can hear both sides at the same time
with one track backwards.


This was recorded on a machine with a misaligned head, I assume. What you
need is to play it back on a machine with a narrower than normal head.


Or it's 1/4 track being played back on 1/2 track? Or mono 1/2 track on
fulltrack?


Entirely possible.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
  #13   Report Post  
William Sommerwerck
 
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Default How to separate 1 waveform composed of two tracks

It may have been a quarter-track stereo machine.
These record two tracks in the same half of the tape
that a half track stereo machine uses for one track.


NOT SO! Quarter-track quarter-inch machines have interleaved, not adjacent,
stereo tracks.

  #14   Report Post  
S O'Neill
 
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Default How to separate 1 waveform composed of two tracks

William Sommerwerck wrote:
It may have been a quarter-track stereo machine.
These record two tracks in the same half of the tape
that a half track stereo machine uses for one track.



NOT SO! Quarter-track quarter-inch machines have interleaved, not adjacent,
stereo tracks.


For the OP, in case anyone didn't already know:

Side 1 L ---
Side 2 R ---
Side 1 R ---
Side 2 L ---

so a 1/2-track machine would get side 1 L and reverse side 2 R on its left
channel, etc, mixed more-or-less equally in the magnetic domain.

  #15   Report Post  
Primaudio
 
Posts: n/a
Default How to separate 1 waveform composed of two tracks

Bad audio tape! Bad tape! behave!


(Ben Nguyen) wrote in message
. com...
I have a bad audio tape that contains both sides of the tape recording
on one side. So when played you can hear both sides at the same time
with one track backwards.

Sonic Foundry has a reverse feature but I cant separate the 2 sides so that
I can reverse just one (The audio clip shows up as just one waveform.)

Is there a way to filter the waveform into its 2 track components?

Help!
Ben


If your source is 1/4", it is almost certainly 1/4 track. (or one of the less
common formats meantioned by HA) Fix it by playing back on the right format
machine.

A Tascam or Otari 4 track would work just fine too. Forward info will be on
tracks 1 and 3.

If it is important material, and you are an analog newbie, get someone who
knows what they're doing to help you. Make sure the heads are de-quaussed and
if the machine hasn't been in service for a while, put a piece of shop-tape on
it first to make sure the sucker isn't going to eat your source.

Proper playback alignment for the format you're dealing with is also nice.


wrote:



.....It may have been a quarter track stereo machine. These record two
tracks in the same half of the tape that a half track stereo machine
uses for one track. You then turn the tape over to continue......
Steve Lane


That's almost right. Quarter track records on half of each track of a
half-track. Corresponds to tracks 1 and 3 of a 4 track head as the tape moves
in the forward direction. Cassette is the same except twice as dinky.

good luck ben. your troubles can be resolved, as long as the source stays
intact.

phillip sztenderowicz






  #16   Report Post  
Ben Nguyen
 
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Default How to separate 1 waveform composed of two tracks

My bad, my original post should have been clearer...

I have a regular audio cassette, the kind that goes into your car's
regular cassette deck. Its an audio book that was purchased a few years
ago, and I was hoping I could try to salvage it digitally.
Since it was obviously some manufacturing problem, I tried contacting the
maker but they have not responded.

I wouldnt mind tinkering with a spare cassette deck if it might do the trick,
but Im not sure whats involved.



"William Sommerwerck" wrote in message ...
I have a bad audio tape that contains both sides of the tape recording
on one side. So when played you can hear both sides at the same time
with one track backwards.


It's probably a fine tape. You're just playing it on the wrong
machine. There are several different track formats some of which will
play back like this when the playback heads don't line up with the
recorded tracks. That's where you need to solve the problem and it may
involve looking around for someone to either do the transfer for you
or, if you have a large number of tapes in that format, loan, rent, or
sell you the correct machine.


To put it a bit more directly... You're playing a half-track tape on a
full-track machine.

  #17   Report Post  
S O'Neill
 
Posts: n/a
Default How to separate 1 waveform composed of two tracks

Primaudio wrote:
That's almost right. Quarter track records on half of each track of a
half-track. Corresponds to tracks 1 and 3 of a 4 track head as the tape moves
in the forward direction. Cassette is the same except twice as dinky.


Just FTR, cassette has left and right on the same side, so a mono (1/2 track)
cassette head plays back a stereo cassette correctly in mono (L+R); in contrast
to the OP's apparent problem.

L1 --
R1 --
R2 --
L2 --

  #18   Report Post  
james
 
Posts: n/a
Default How to separate 1 waveform composed of two tracks

In article ,
Ben Nguyen wrote:

I wouldnt mind tinkering with a spare cassette deck if it might do the trick,
but Im not sure whats involved.


If you play it on a stereo deck, do you get the crosstalk in both
channels? If not, the solution should be obvious.

Otherwise, I'm sticking to my first suggestion, adjust the head geometry
so that it isn't reading both tracks. Sometimes the azimuth screw
gives enough range to do it.
  #19   Report Post  
DaveDrummer
 
Posts: n/a
Default How to separate 1 waveform composed of two tracks


"Richard Crowley" wrote in message
...

"james" wrote in message
news:9w9ac.16452$Q45.13642@fed1read02...
In article ,
Ben Nguyen wrote:

I have a bad audio tape that contains both sides of the tape recording
on one side. So when played you can hear both sides at the same time
with one track backwards.


Have you considered adjusting the head geometry first? This sounds like
the sort of thing you should try to fix in the analog domain. Once
the green beans touch the mashed potatoes, the plate becomes toxic,
right?


No, this happens only with "creamed" vegetables (creamed
corn, creamed peas, etc.) eeeeewwwwww! :-)




hey its all goin to the same stomach!


  #20   Report Post  
William Sommerwerck
 
Posts: n/a
Default How to separate 1 waveform composed of two tracks

I have a regular audio cassette, the kind that goes
into your car's regular cassette deck. It's an audio
book that was purchased a few years ago, and I was
hoping I could try to salvage it digitally. Since it was
obviously some manufacturing problem, I tried
contacting the maker but they have not responded.


YET ANOTHER example of asking for assistance and NOT giving the full story.
Shame, shame, shame.

The kind of problem you're describing SHOULD NOT occur with a Compact Cassette,
because the left and right tracks are adjacent, and correctly "sum to mono" when
played on a mono machine.

Several people have suggested severe head misalignment, and I think that's
likely. Try playing the tape on other machines -- both mono and stereo -- to see
what happens. This should reveal whether the problem is with the tape or the
player.



  #21   Report Post  
Steve King
 
Posts: n/a
Default How to separate 1 waveform composed of two tracks

"Ben Nguyen" wrote in message
...
My bad, my original post should have been clearer...

I have a regular audio cassette, the kind that goes into your car's
regular cassette deck. Its an audio book that was purchased a few years
ago, and I was hoping I could try to salvage it digitally.
Since it was obviously some manufacturing problem, I tried contacting the
maker but they have not responded.

I wouldnt mind tinkering with a spare cassette deck if it might do the

trick,
but Im not sure whats involved.

I seem to recall that early talking book recordings on cassette were
sometimes prepared for a special cassette machine that enabled the use of
the two stereo tracks as four separate mono tracks. I assume that hose PB
machines had reverse play and head switching to play a single coherent mono
track continuously from track 1 through track 4.

Steve King


  #22   Report Post  
William Sommerwerck
 
Posts: n/a
Default How to separate 1 waveform composed of two tracks

I seem to recall that early talking book recordings on
cassette were sometimes prepared for a special
cassette machine that enabled the use of the two stereo
tracks as four separate mono tracks. I assume those PB
machines had reverse play and head switching to play a
single coherent mono track continuously from track 1
through track 4.


The thought had crossed my mind. Westinghouse made a cassette recorder that
allowed all four tracks to be recorded on independently. However, Philips did
not like such machines, as they destroyed the mono/stereo compatibility that had
been consciously designed into the system.

  #25   Report Post  
Scott Dorsey
 
Posts: n/a
Default How to separate 1 waveform composed of two tracks

Ben Nguyen wrote:

I have a regular audio cassette, the kind that goes into your car's
regular cassette deck. Its an audio book that was purchased a few years
ago, and I was hoping I could try to salvage it digitally.
Since it was obviously some manufacturing problem, I tried contacting the
maker but they have not responded.


This can be one of two problems:

1. bad head height on the cassette duplicator.

2. bad head height on the duplication master.

Almost certainly if you crank the head height on your cassette deck up
and down (and you may need to tweak azimuth in the process), you will
be able to get it to play properly. Be sure to realign the deck with
a reference tape after this process.

If not, it's a duplication master issue and you're screwed. But this is
much less likely.

I wouldnt mind tinkering with a spare cassette deck if it might do the trick,
but Im not sure whats involved.


Depends on the deck, but they should all have adjustments for head height
and azimuth, although on the cheaper decks they interact a lot.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."


  #26   Report Post  
Steve
 
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Default How to separate 1 waveform composed of two tracks

"William Sommerwerck" wrote in message ...
It may have been a quarter-track stereo machine.
These record two tracks in the same half of the tape
that a half track stereo machine uses for one track.


NOT SO! Quarter-track quarter-inch machines have interleaved, not adjacent,
stereo tracks.


I don't think you read what I posted. I said "two tracks". Not stereo tracks.
That is why you would get forward and reverse mixed.

Steve Lane
  #29   Report Post  
hank alrich
 
Posts: n/a
Default How to separate 1 waveform composed of two tracks

Ben Nguyen wrote:

I have a regular audio cassette, the kind that goes into your car's
regular cassette deck. Its an audio book that was purchased a few years
ago, and I was hoping I could try to salvage it digitally.
Since it was obviously some manufacturing problem, I tried contacting the
maker but they have not responded.


Turn off the channel that's backwards when dubbing? Flip tape, rinse,
and repeat? Perhaps.

--
ha
  #30   Report Post  
Brian Downey
 
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Default How to separate 1 waveform composed of two tracks

Hi Mike:
There was at least one talking book format that certainly did - and still
does exist. Brilliance Corp. from Michigan records program material in mono
on all four tracks of a stereo cassette and sells a earphone adapter that
switches from L to R -- but both L and R were recorded in the same direction
so if you play it on a stereo cassette player you hear both tracks but in
the same direction. To be more specific; first you listen to the L track
then you flip the cassette and listen the L track going the opposite
direction then flip the cassette again but also switch the adapter so you
are listening to the R track in the original direction and then in the other
direction. They also use a Lexicon "Compander" to time compress the audio
about 10% ( I know, in audio terms a compander doesn't do time compression
but it was the name of the rack mounted computer Lexicon sold for around
$8,000). The result is you get the entire book, unedited on usually just
one more cassette than the other publishers use to give you a 50% edited
version. I designed the system for them back in the early 1980s and (after
reneging on their contract with me) they started doing everything in-house
in the late 1980s. They continue putting out around a dozen books a year.
Great idea and really excellent narration/acting - just be careful getting
into a business relationship with them ;-)
Brian

"Mike Rivers" wrote in message
news:znr1080691077k@trad...

In article

writes:

I seem to recall that early talking book recordings on
cassette were sometimes prepared for a special
cassette machine


machines had reverse play and head switching to play a
single coherent mono track continuously from track 1
through track 4.


The thought had crossed my mind. Westinghouse made a cassette recorder

that
allowed all four tracks to be recorded on independently. However,

Philips did
not like such machines, as they destroyed the mono/stereo compatibility

that
had
been consciously designed into the system.


I thought about a special talking book format too, but I suspect that
if it ever really existed, it was gone by the time cassette players
became common in cars.

TEAC had to get a special license from Philips to make the 4-track
cassette PortaStudio because it didn't conform to the cassette track
recording standard format.



--
I'm really Mike Rivers )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo





  #31   Report Post  
hank alrich
 
Posts: n/a
Default How to separate 1 waveform composed of two tracks

William Sommerwerck wrote:

I seem to recall that early talking book recordings on
cassette were sometimes prepared for a special
cassette machine that enabled the use of the two stereo
tracks as four separate mono tracks. I assume those PB
machines had reverse play and head switching to play a
single coherent mono track continuously from track 1
through track 4.


The thought had crossed my mind. Westinghouse made a cassette recorder
that allowed all four tracks to be recorded on independently. However,
Philips did not like such machines, as they destroyed the mono/stereo
compatibility that had been consciously designed into the system.


Hey, now, could this mystery tape have been recorded on a cassette
4-tracker than the recordist flipped wrongly?

--
ha
  #32   Report Post  
W. Williams
 
Posts: n/a
Default How to separate 1 waveform composed of two tracks


"Steve King" wrote:
edit
I seem to recall that early talking book recordings on cassette were
sometimes prepared for a special cassette machine that enabled the use of
the two stereo tracks as four separate mono tracks. I assume that hose PB
machines had reverse play and head switching to play a single coherent

mono
track continuously from track 1 through track 4.


Even if this is the case, you should still end up with two separate tracks
when using a standard stereo cassette player, except that one of these will
merely be in reverse.

I re-read the original post and what bothers me is that he seems to be
saying that he recorded in mono. This leads me to believe that all he may
need to do is set SoundForge to record a stereo file, after which he can
create two new mono tracks and then use the reverse function to correct the
backward one.

W


  #34   Report Post  
Mike Rivers
 
Posts: n/a
Default How to separate 1 waveform composed of two tracks


In article dLsac.42542$JO3.32102@attbi_s04 writes:

There was at least one talking book format that certainly did - and still
does exist. Brilliance Corp. from Michigan records program material in mono
on all four tracks of a stereo cassette and sells a earphone adapter that
switches from L to R


That makes a certain amount of sense if you have a lot of talking
books. It saves shelf space. Not too practical for one of the
contemporary applications, though. Lots of yuppies who don't have time
to read books at home listen to them in their car while commuting.

To be more specific; first you listen to the L track
then you flip the cassette and listen the L track going the opposite
direction then flip the cassette again but also switch the adapter so you
are listening to the R track in the original direction and then in the other
direction.


I have a lot of concert tapes recorded that way with a quarter track
recorder on 1/4" tape. Record one pass on the left channel, (track 1),
flip the tape over and record the next pass (track 4), then flip the
tape over again, switch to the right channel (track 3), etc. The usual
scheme to keep things somewhat sane was to record the first half on
the left channel, going to the second side if necessary, then record
the second half on the right channel. With this system, however,
playing the tape on a half track machine would give you the first half
of the show forward on the left channel and the last of the second
part of the show backward on the right channel. That often wouldn't
show up until you were halfway through the tape. Surprise!

Most home receivers and stereo preamps of the day had a selector
switch that allowed you to listen to either the left or right channel
alone, sending it to both speakers, so it was convenient to listen to
tapes recorded this way. It was obviously from the days before we used
to say "tape is cheap."

They also use a Lexicon "Compander" to time compress the audio
about 10% ( I know, in audio terms a compander doesn't do time compression
but it was the name of the rack mounted computer Lexicon sold for around
$8,000). The result is you get the entire book, unedited on usually just
one more cassette than the other publishers use to give you a 50% edited
version.


The first crude solid state speed changer I ever saw was in a cassette
player designed for llistening to talking books and other recorded
speech. It was in one of the old style portable mono cassette players
about the size of three paperback books and it had a speed control
that would go up to double speed, and keep the program on pitch. It
didn't sound great but it made "reading" much faster.


--
I'm really Mike Rivers )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo
  #35   Report Post  
Tom McCreadie
 
Posts: n/a
Default How to separate 1 waveform composed of two tracks

S O'Neill wrote:

For the OP, in case anyone didn't already know:

Side 1 L ---
Side 2 R ---
Side 1 R ---
Side 2 L ---

This reminded me of an experience as a poor student in the late 70's
when I would feed my stereo 71/2 ips quartertrack with scrap tape
which a friend of a friend smuggled out of the EMI studios in London:
during playback of quiet passages in one my recordings I could just
discern a low level version of the theme from Dvorak's New World
Symphony - played backwards at half speed. I kid you not. All very
logical when you think through the track speed-, width-, geometry- and
erasure issues. Actually, I was gobsmacked how easily recognizable
that phantom recording was...those 'ol hot-shot composers knew how to
pen a good tune g.

Tom McCreadie
(please remove "spamjam." for my real address)
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