sound file resampling

Archived from groups: rec.audio.misc,rec.audio.opinion,rec.audio.pro,rec.audio.tech (More info?)

Here's the situation:
Some open reel tapes were originally recorded at 3 3/4 i.p.s. NOW, the only
deck available, only plays at the higher speeds of 7.5 and 15 i.p.s.
Assuming one of those tapes is played at 7.5 into my sound card, could I
merely sample at TWICE the normal rate (88.2 KHZ) then reset the rate to
44.1 once it's in the pc to get it to sound normal? I know this works since
I use this technique to get an old 78 to turn at a lower speed on the
turntable when it's damaged.
The problem now is, let's say I don't have that ANALOG tape, but I have a CD
of that original tape played at the higher 7.5 Can I rip that file from the
cd, get it into my Sound Forge software and resample to get it to sound
normal or am I at a dead-end? I've got a gut feeling that I'll have to have
the ANALOG tape available so I can get the sound wave through my sound card.
(it's an Audiophile2496) Anyone? Am I making sense?

thanks, ken

--
1st Class Restoration
"Put your old music on CD"
www.dvbaudiorestoration.com

Archived from groups: rec.audio.misc,rec.audio.opinion,rec.audio.pro,rec.audio.tech (More info?)

Ken Bouchard wrote:

> Here's the situation:
> Some open reel tapes were originally recorded at 3 3/4 i.p.s. NOW, the only
> deck available, only plays at the higher speeds of 7.5 and 15 i.p.s.
> Assuming one of those tapes is played at 7.5 into my sound card, could I
> merely sample at TWICE the normal rate (88.2 KHZ) then reset the rate to
> 44.1 once it's in the pc to get it to sound normal? I know this works since
> I use this technique to get an old 78 to turn at a lower speed on the
> turntable when it's damaged.
> The problem now is, let's say I don't have that ANALOG tape, but I have a CD
> of that original tape played at the higher 7.5 Can I rip that file from the
> cd, get it into my Sound Forge software and resample to get it to sound
> normal or am I at a dead-end?

You can't resample it to get it sound normal. You need to tell the
software that, while the WAV file (that you ripped from CD) denotes a
sampling rate of 44100 Hz, the actual sampling rate should be 22050 Hz.
Which is a different process from resampling. (Maybe you know that,
but I just thought I'd clarify since you used "reset the rate" in one
instance and "resample" in another when it appears you should've
meant the same thing in both instances.)

The most obvious negative side effect, though, is that your CD of
the original tape played at double speed is still only sampled at
44100 Hz. So when you change the sampling rate without changing
the sample data, you're going to lose an octave of bandwidth (err,
um, I mean you're going to lose the highest octave of the audible
spectrum). You will only get sound up to about 10000 Hz instead
of up to about 20000 Hz.

Losing the upper octave isn't a problem with with playing 78s "too
slowly" because you're collecting extra information by taking
twice as many (or whatever) samples as you would need to if you
played the 78 full speed. But when you play a tape double speed
and don't double the sampling rate, you're getting 44100 samples
for 7.5 inches of the tape when you should be getting 44100 for
3.75 inches, so you're throwing away high-frequency information.

Oh, of course, the other reason it's not a problem for 78s is it's
highly doubtful they contain any useful information above 10000 Hz
in the first place, whereas 3.75 in/s tape could.

- Logan

Archived from groups: rec.audio.misc,rec.audio.opinion,rec.audio.pro,rec.audio.tech (More info?)

"Ken Bouchard" <ke_bouchard@adelphia.net> wrote in message
news:ueKdneZScZ_X-JTfRVn-tQ@adelphia.com

> Some open reel tapes were originally recorded at 3 3/4 i.p.s. NOW,
> the only deck available, only plays at the higher speeds of 7.5 and
> 15 i.p.s. Assuming one of those tapes is played at 7.5 into my sound
> card, could I merely sample at TWICE the normal rate (88.2 KHZ) then
> reset the rate to 44.1 once it's in the pc to get it to sound normal?

It will sound more normal and it may be your best option, but there may be
some need for additional equalization touch up.

Playing a tape at twice the speed doesn't quite give you twice the bandpass.
There are high frequency losses that are not dependent on tape speed, such
as the effects of tape head inductance and other losses in the reproduce
head electronics.

> I know this works since I use this technique to get an old 78 to turn at a
> lower speed
> on the turntable when it's damaged.

So you haven't tried it yet?

> The problem now is, let's say I don't have that ANALOG tape, but I
> have a CD of that original tape played at the higher 7.5

Whoops! Bottom line - your transcriptions will hit a brick wall at about 11
KHz due to the characteristics of 44 KHz sampling. But, as I recall the old
3.75 ips tapes weren't good for much past that.

> Can I rip that file from the cd, get it into my Sound Forge software and
> resample to get it to sound normal or am I at a dead-end?

Seems like. I know I could make it work almost well enough with Adobe
Audition.

> I've got a
> gut feeling that I'll have to have the ANALOG tape available so I can
> get the sound wave through my sound card. (it's an Audiophile2496)

You're right on.

> Anyone? Am I making sense?

Yeah. Try it, and then do a little remastering. You'll probably get
something that will be useful, if not the ulitmate in hi fi.

Archived from groups: rec.audio.misc,rec.audio.opinion,rec.audio.pro,rec.audio.tech (More info?)

Dimitrios Tzortzakakis <use@address.below> wrote:
>Quote:"One possibility could be to connect the motordrive to a frequency
>transformer.
>Which controls AC motor speed by altering the frequency of the mains."
>most tape decks use dc motors.Correct me if I am wrong.These frequency
>transformers are very expensive, though,If it's a dc motor it's much easier
>to change its speed by the voltage.

No, most older open-reel decks use hysteresis synchronous motors that lock
to the line frequency. In general, though, operating these at half the
speed they are designed for is going to result in a lot of cogging and a
lot of flutter.

There are other machines that use three-phase motors with reference
oscillators, or DC motors with servo control. The Ampex ATR-100 is a good
example of a servo-controlled machine that can be run down fairly accurately
to the low speed of consumer decks without changing the capstan diameter.
The Revox A77 is a good example of a multipole motor arrangement driven
by a reference oscillator, which is also reasonable at low speeds.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Archived from groups: rec.audio.pro (More info?)

On Wed, 09 Feb 2005 04:19:02 GMT, Logan Shaw
<lshaw-usenet@austin.rr.com> wrote:

>Oh, of course, the other reason it's not a problem for 78s is it's
>highly doubtful they contain any useful information above 10000 Hz
>in the first place, whereas 3.75 in/s tape could.

Just because I have nothing better to do right now, I'll
add that there were, in song and story, never seen one,
microgroove 78's. Somebody who actually knows something
about it please chime in.

Not what you meant of course.

Chris Hornbeck

Archived from groups: rec.audio.misc,rec.audio.pro (More info?)

In article <ueKdneZScZ_X-JTfRVn-tQ@adelphia.com> ke_bouchard@adelphia.net writes:

> Some open reel tapes were originally recorded at 3 3/4 i.p.s. NOW, the only
> deck available, only plays at the higher speeds of 7.5 and 15 i.p.s.
> Assuming one of those tapes is played at 7.5 into my sound card, could I
> merely sample at TWICE the normal rate (88.2 KHZ) then reset the rate to
> 44.1 once it's in the pc to get it to sound normal?

Yes, but equalization is different at 3-3/4 and 7-1/2 IPS. If you play
the tapes back at double speed, not only will the EQ be wrong, but you
may lose most of the top octave (if there's anything there to lose)
because the recorder electronics may be bandwidth-limited, or you may
run out of headroom on the playback amplifier. But there's no reason
not to give it a try.

> The problem now is, let's say I don't have that ANALOG tape, but I have a CD
> of that original tape played at the higher 7.5 Can I rip that file from the
> cd, get it into my Sound Forge software and resample to get it to sound
> normal or am I at a dead-end?

Aw, geez - can't you just do the job right? There are plenty of tape
decks available that run at 3-3/4 ips. Get one together with the tape
and do a transfer. You'll never get it to sound "normal" going through
that many wrong processes. But then, just how good is this recording
and how important is it to get an accurate transfer? Do you want to
publish it, or just listen to see what's there?




--
I'm really Mike Rivers (mrivers@d-and-d.com)
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 here: double-m-eleven-double-zero at yahoo

Archived from groups: rec.audio.misc,rec.audio.pro (More info?)

In article <ueKdneZScZ_X-JTfRVn-tQ@adelphia.com> ke_bouchard@adelphia.net writes:

> Some open reel tapes were originally recorded at 3 3/4 i.p.s. NOW, the only
> deck available, only plays at the higher speeds of 7.5 and 15 i.p.s.
> Assuming one of those tapes is played at 7.5 into my sound card, could I
> merely sample at TWICE the normal rate (88.2 KHZ) then reset the rate to
> 44.1 once it's in the pc to get it to sound normal?

No. The playback electronics bandwidth won't be wide enough. In addition,
the optimal head gap for 15 ips and 3 3/4 ips is different; you need the
narrow-gap heads for slow speed consumer tapes.

The equalization is different, which is a whole other nightmare. And
the absolute worst part is that you'll find a lot of those consumer tapes
are recorded with quarter track heads.

Just do it right in the first place and don't futz around.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Archived from groups: rec.audio.pro (More info?)

Buster Mudd <mr_furious@mail.com> wrote:
>Scott Dorsey wrote:
>>
>> I only know about a couple of them, both released by R. Crumb in the
>> seventies. I can only think it was out of some misguided nostalgia.
>
>R.Crumb, the cartoonist? Or G.Crumb, the composer?

The cartoonist. I believe he also plays banjo with the Cheap Suit
Serenaders.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Archived from groups: rec.audio.pro (More info?)

Scott Dorsey wrote:

> Buster Mudd <mr_furious@mail.com> wrote:
>
>>Scott Dorsey wrote:
>>
>>>I only know about a couple of them, both released by R. Crumb in the
>>>seventies. I can only think it was out of some misguided nostalgia.
>>
>>R.Crumb, the cartoonist? Or G.Crumb, the composer?
>
>
> The cartoonist. I believe he also plays banjo with the Cheap Suit
> Serenaders.


This is true.

Archived from groups: rec.audio.pro (More info?)

On 9 Feb 2005 10:00:13 -0500, kludge@panix.com (Scott Dorsey) wrote:

>Chris Hornbeck <chrishornbeckremovethis@att.net> wrote:
>>On Wed, 09 Feb 2005 04:19:02 GMT, Logan Shaw
>><lshaw-usenet@austin.rr.com> wrote:
>>
>>>Oh, of course, the other reason it's not a problem for 78s is it's
>>>highly doubtful they contain any useful information above 10000 Hz
>>>in the first place, whereas 3.75 in/s tape could.
>>
>>Just because I have nothing better to do right now, I'll
>>add that there were, in song and story, never seen one,
>>microgroove 78's. Somebody who actually knows something
>>about it please chime in.
>
>I only know about a couple of them, both released by R. Crumb in the
>seventies. I can only think it was out of some misguided nostalgia.

I think there was also a Randy Newman 78 released by Warner Bros. as
some kind of promo stunt.

Al

Archived from groups: rec.audio.pro (More info?)

play_on <playonAT@comcast.net> writes:

>On 9 Feb 2005 10:00:13 -0500, kludge@panix.com (Scott Dorsey) wrote:

>>Chris Hornbeck <chrishornbeckremovethis@att.net> wrote:
>>>On Wed, 09 Feb 2005 04:19:02 GMT, Logan Shaw
>>><lshaw-usenet@austin.rr.com> wrote:
>>>
>>>>Oh, of course, the other reason it's not a problem for 78s is it's
>>>>highly doubtful they contain any useful information above 10000 Hz
>>>>in the first place, whereas 3.75 in/s tape could.
>>>
>>>Just because I have nothing better to do right now, I'll
>>>add that there were, in song and story, never seen one,
>>>microgroove 78's. Somebody who actually knows something
>>>about it please chime in.
>>
>>I only know about a couple of them, both released by R. Crumb in the
>>seventies. I can only think it was out of some misguided nostalgia.

>I think there was also a Randy Newman 78 released by Warner Bros. as
>some kind of promo stunt.

There was Moby Grape's "WOW" which featured a single 78-cut on the
otherwise 33.33 album. That cut, btw, featured Arthur Godfrey on
uke.

Archived from groups: rec.audio.pro (More info?)

Mike Rivers wrote:
> In article <cudama$mf1$1@panix2.panix.com> kludge@panix.com writes:
>
>
>>>R.Crumb
>
>
>>The cartoonist. I believe he also plays banjo with the Cheap Suit
>>Serenaders.
>
>
> He's a serious collector and scholar of early jazz and hokum music and
> indeed gets this band together occasionally.


Every year.

Archived from groups: rec.audio.misc,rec.audio.pro (More info?)

That's why nobody uses tapes and reel-to-reel decks anymore.All these
systems were user-hostile, you had to fiddle with tape speeds, tape types
(Normal, CrO2, Metal), equalizations, bias settings, track numbers, head
types, most of these problems occur with cassetes, too.

--
Tzortzakakis Dimitriïs
major in electrical engineering, freelance electrician
FH von Iraklion-Kreta, freiberuflicher Elektriker
dimtzort AT otenet DOT gr
Ï "Scott Dorsey" <kludge@panix.com> Ýãñáøå óôï ìÞíõìá
news:cud8ul$fbd$1@panix2.panix.com...
> In article <ueKdneZScZ_X-JTfRVn-tQ@adelphia.com> ke_bouchard@adelphia.net
writes:
>
> > Some open reel tapes were originally recorded at 3 3/4 i.p.s. NOW, the
only
> > deck available, only plays at the higher speeds of 7.5 and 15 i.p.s.
> > Assuming one of those tapes is played at 7.5 into my sound card, could I
> > merely sample at TWICE the normal rate (88.2 KHZ) then reset the rate to
> > 44.1 once it's in the pc to get it to sound normal?
>
> No. The playback electronics bandwidth won't be wide enough. In
addition,
> the optimal head gap for 15 ips and 3 3/4 ips is different; you need the
> narrow-gap heads for slow speed consumer tapes.
>
> The equalization is different, which is a whole other nightmare. And
> the absolute worst part is that you'll find a lot of those consumer tapes
> are recorded with quarter track heads.
>
> Just do it right in the first place and don't futz around.
> --scott
>
> --
> "C'est un Nagra. C'est suisse, et tres, tres precis."

Archived from groups: rec.audio.pro (More info?)

In article <cufmsr$j03$1@usenet.otenet.gr> use@address.below writes:

> That's why nobody uses tapes and reel-to-reel decks anymore.All these
> systems were user-hostile, you had to fiddle with tape speeds, tape types
> (Normal, CrO2, Metal), equalizations, bias settings, track numbers, head
> types, most of these problems occur with cassetes, too.

I love sarcastic humor right before lunch.


--
I'm really Mike Rivers (mrivers@d-and-d.com)
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 here: double-m-eleven-double-zero at yahoo