78 RPM test tone record

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

Does anyone know if a 78 RPM record with frequency spot tones exists,
and if so, how to obtain such a record?

I would like to borrow the test tone practice from the open reel
world, and apply it to phonograph transcriptions to digital format.
The test tones would provide a reference so that the speed and EQ of
the source system would be "documented", as would overall performance
of the source equipment should that need to be compensated for later.

Failing the existence of such a 78 RPM test record, I would like to
know of people who can master such a recording. Please contact me for
more details.

Eric Jacobs
The Audio Archive

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

Try this LP:

http://www.cardas.com/cgi-bin/main [...] oduct_id=5


"anybody-but-bush" <Anybody But Bu$h@YAHOO.com> escribió en el mensaje
news%zNc.147$Jp6.40@newsread3.news.atl.earthlink.net...
> Just wondering why not play a 33rpm record at 78 and calculate (or just
measure) the new
> higher frequencies.
> I don't know a source of 33 or 78 RPM test records.
>
> Phil
> "EricJ" <ericj@theaudioarchive.com> wrote in message
> news:ffc7e233.0407271259.5c2a9369@posting.google.com...
> : Does anyone know if a 78 RPM record with frequency spot tones exists,
> : and if so, how to obtain such a record?
> :
> : I would like to borrow the test tone practice from the open reel
> : world, and apply it to phonograph transcriptions to digital format.
> : The test tones would provide a reference so that the speed and EQ of
> : the source system would be "documented", as would overall performance
> : of the source equipment should that need to be compensated for later.
> :
> : Failing the existence of such a 78 RPM test record, I would like to
> : know of people who can master such a recording. Please contact me for
> : more details.
> :
> : Eric Jacobs
> : The Audio Archive
>
>

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

EricJ <ericj@theaudioarchive.com> wrote:
>Does anyone know if a 78 RPM record with frequency spot tones exists,
>and if so, how to obtain such a record?

It used to. Columbia sold a tone ladder disc that also had some
sweeps.

>I would like to borrow the test tone practice from the open reel
>world, and apply it to phonograph transcriptions to digital format.
>The test tones would provide a reference so that the speed and EQ of
>the source system would be "documented", as would overall performance
>of the source equipment should that need to be compensated for later.

The problem is that the speed and EQ of the original recording system
isn't documented, especially in the acoustic era. You'll find stuff
varies all over the place, even on the same label over the same year.
So much of it has to be done by ear.

>Failing the existence of such a 78 RPM test record, I would like to
>know of people who can master such a recording. Please contact me for
>more details.

You could put a microgroove stylus on, then use the Shure S15 test
record at 78 rpm. You'd have to apply some fudge factors since it
was recorded at 33 rpm, but there's no reason you couldn't play it
back and compensate for the shift in the RIAA constants.

If you really want a 78 rpm test disc, I could probably cut you an
acetate, but you won't like what it will cost, and it won't tell you
anything useful, really. Just tell me what emphasis curve and speed
you want and send me a lot of money. I think that Don Grossinger
now of Masterdisc in NYC has a 78 cutter sitting around too, although
I doubt he can do any non-RIAA curves. I bet also that Charlie at
Kinura Records might have one in the closet somewhere, since he has
nearly everything else.
--scott

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

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

"Arny Krueger" <arnyk@hotpop.com> wrote in message
news:6O2dnfauaeBNTJvcRVn-ow@comcast.com...
> "Suso Ramallo" <ramallo(no spam)@teleline.es> wrote in message
> news:2mo0ojFpaj5cU1@uni-berlin.de
>
> > Try this LP:
> >
> >
>
http://www.cardas.com/cgi-bin/main [...] nt_id=7&pa
gestring=Accessories&product_id=5
>
> Some adjustments are going to have to be made, as the RIAA premphasis on
the
> record will get moved up in frequency by a factor of 2.34.

Snip


That's not taking into account that a 33RPM microgroove stylus is completely
different to a 78 stylus and if the latter is used on a 33RPM test record,
it will no longer be a good test for anything!

TonyP.

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

TonyP <TonyP@optus.net.com.au> wrote:
>
>That's not taking into account that a 33RPM microgroove stylus is completely
>different to a 78 stylus and if the latter is used on a 33RPM test record,
>it will no longer be a good test for anything!

That's true, but I don't see why you can't just drop a microgroove stylus
on the thing. The only thing that you'll miss is the ability to measure
tracking effects (which will be different with the different stylus). System
frequency response should be the same if the stylus assembly has the same mass.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

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

Arny Krueger <arnyk@hotpop.com> wrote:
>
>I've played 78s with microgroove styli, and there was no damage to either
>the stylus or the 78.

There was damage to the 78, from your scraping the bottom of the groove
and bouncing back and forth as it mistracks. On shellacs it probably isn't
going to wreck it in one play, but on acetates it sure will.

>The worst problem I had was that the microgroove stylus snuggled down low in
>the 78 groove where more of the dirt was. Playback was therefore nosier than
>it might have been with a properly-fitting stylus.

Even if the record was absolutely clean, it would be much noisier and far
more distorted because it is scraping the bottom and not following the
modulation accurately.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

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

kludge@panix.com (Scott Dorsey) wrote in message >
> The problem is that the speed and EQ of the original recording system
> isn't documented, especially in the acoustic era. You'll find stuff
> varies all over the place, even on the same label over the same year.
> So much of it has to be done by ear.
>

Agreed - no question about that.

Since this is a raw transcription for preservation/archival purposes,
the goal is not to tweak the EQ during playback, but rather document
whatever EQ happens to be applied (RIAA, none, or other) during playback.
Before someone re-EQs a raw trancription, it's good to know if any EQ
was applied during the transcription from analog to digital. Without
a reference or baseline, there's no way to know what you're starting
with when re-EQing the digital transcription.


>
> You could put a microgroove stylus on, then use the Shure S15 test
> record at 78 rpm. You'd have to apply some fudge factors since it
> was recorded at 33 rpm, but there's no reason you couldn't play it
> back and compensate for the shift in the RIAA constants.
>

Not sure if swapping the stylus will work. Admittedly, just a
stylus swap is not a complete transducer swap, since you keep the
cartridge. I'm wondering if the frequency response changes with
different styli. All else being equal, will a microgroove stylus
in a microgroove record have the same FR as a wide groove stylus
in a wide groove record (no change in cartridge)? I know that
there can be quite a bit of variation in the cartridges of
some manufacturers (I won't name names), but I'm less clear on
the consistency of the moving magnet stylus assembly. Also,
what impact will VTF have on overall FR if the same cartridge
is used, since VTF is much higher for 78s than for microgrooves.


> If you really want a 78 rpm test disc, I could probably cut you an
> acetate, but you won't like what it will cost, and it won't tell you
> anything useful, really. Just tell me what emphasis curve and speed
> you want and send me a lot of money. I think that Don Grossinger
> now of Masterdisc in NYC has a 78 cutter sitting around too, although
> I doubt he can do any non-RIAA curves. I bet also that Charlie at
> Kinura Records might have one in the closet somewhere, since he has
> nearly everything else.

Here's a crude spec:

78 RPM, no EQ (flat, constant velocity), series of 1 or 2-second spot tones
(about 13 tones in octave and 1/3 octave intervals from 20 Hz to 20 kHz),
in 2/3/4/5 mil groove widths (ie. 4 sets of 13 test tones). Not sure
if the lack of EQ will create tracking problems - although vertical
tracking forces for 78s are quite a bit higher than for microgroove
recordings. I believe frequencies above 16 kHz are unusual on 78s,
but again, this is a crude spec.

From an archival/transcription process point of view, recording test
tones makes sense (to me at least). This is just like recording test
tones on an analog tape so that it can be played on a different machine
with a relatively flat frequency response. But instead of playing the
phonograph record on a different machine, we are playing it in a
different domain (digital), and you want some sort of reference signal
to pass through the analog-to-digital process as a reference for any
future signal processing (speed/pitch, EQ). I know that much of the
equalization is subjective, just as it was when the records were
originally cut - but the reference tones allow you to undo the
transcription playback EQ (if any) rather than guess what happened
during the transcription to digital.

Just curious if others see the value in this process of recording
spot tones into digital transcriptions. I know this is an
archival/preservation process question, which is not the focus
of this group.

However, the cutting of records and test records in general does
fall within the scope of this group.


> --scott