help with open reel playback

[dave]

Hello,

I am not sure if this is a good forum for this inquiry, or if one exists,
but here goes:

I am trying to play back a very old open-reel tape recording for a friend of
mine. It has some home recordings of deceased family members, etc. So
basically I am trying to do audio archiving for him. I own several old open
reel machines which generally have not seen much use to this point and I am
certainly no expert on the format.

The problem I am having is that the audio in the track/tracks where the
voices are recorded has a severe 60 Hz hum over top of it. The hum is very
even in amplitude and is so strong that it sounds like it is modulating the
fairly faint voices underneath. I am recording to my computer and have
tried filtering the hum out with software but the audio is still garbled
from the strong 60 Hz signal. I am thinking that the head on the machine
that was used to record these voice tracks was aligned a little off to one
side or something like that and that I might be able to get a much cleaner
take if I were able to move the head on one of my machines to align better
with the track. I am not talking about azimuth angle but actual side to
side alignment. I am not sure if this even makes sense but it is the only
thing I could think of. If anybody has a better idea on this topic, I would
be most appreciative hearing from you.


thanks,

Dave

[Scott Dorsey]

In article >, dave > wrote:
>I am trying to play back a very old open-reel tape recording for a friend of
>mine. It has some home recordings of deceased family members, etc. So
>basically I am trying to do audio archiving for him. I own several old open
>reel machines which generally have not seen much use to this point and I am
>certainly no expert on the format.

First question: do you know if the tracks you have are matching the tracks
of the original machine? If you have a half-track machine and there is a
quarter-track tape and there is hum on the "other side" of the tape, you
will get him.

>The problem I am having is that the audio in the track/tracks where the
>voices are recorded has a severe 60 Hz hum over top of it. The hum is very
>even in amplitude and is so strong that it sounds like it is modulating the
>fairly faint voices underneath. I am recording to my computer and have
>tried filtering the hum out with software but the audio is still garbled
>from the strong 60 Hz signal. I am thinking that the head on the machine
>that was used to record these voice tracks was aligned a little off to one
>side or something like that and that I might be able to get a much cleaner
>take if I were able to move the head on one of my machines to align better
>with the track. I am not talking about azimuth angle but actual side to
>side alignment. I am not sure if this even makes sense but it is the only
>thing I could think of. If anybody has a better idea on this topic, I would
>be most appreciative hearing from you.

It's possible. Most tape machines have head height settings.

Spraying Magna-See on the tape might help you figure out what is up.
--scott

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

[Roy W. Rising]

"dave" > wrote:
> Hello,
>
> I am not sure if this is a good forum for this inquiry, or if one exists,
> but here goes:
>
> I am trying to play back a very old open-reel tape recording for a friend
> of mine. It has some home recordings of deceased family members, etc.
> So basically I am trying to do audio archiving for him. I own several
> old open reel machines which generally have not seen much use to this
> point and I am certainly no expert on the format.
>
> The problem I am having is that the audio in the track/tracks where the
> voices are recorded has a severe 60 Hz hum over top of it. The hum is
> very even in amplitude and is so strong that it sounds like it is
> modulating the fairly faint voices underneath. I am recording to my
> computer and have tried filtering the hum out with software but the audio
> is still garbled from the strong 60 Hz signal. I am thinking that the
> head on the machine that was used to record these voice tracks was
> aligned a little off to one side or something like that and that I might
> be able to get a much cleaner take if I were able to move the head on one
> of my machines to align better with the track. I am not talking about
> azimuth angle but actual side to side alignment. I am not sure if this
> even makes sense but it is the only thing I could think of. If anybody
> has a better idea on this topic, I would be most appreciative hearing
> from you.
>
> thanks,
>
> Dave

There are four adjustments that pertain to head allignment, "side to side"
is not one of them. They are: Azimuth (gap perpendicularity to tape
motion), Zenith (front/back tilt), Height (centering of gap to track) and
Wrap (centering of gap to tape/head contact area). Azimuth is the most
common misalignment problem, and usually is easy to handle.

The 60Hz hum problem more likely is a "buzz" problem ... harmonics of the
60Hz hum. I don't know which software does the best job. The Roland 700
Noise/Hum Eliminator is AD/DA digital hardware that does an amazing job.
If, indeed, the 60Hz has modulated the speech, then there's not much that
can be done.

What is the track format of the tape, and about how long is it. I'm set up
to clean and digitize 7.5- and 15 ips half- and full track 1/4" tape. I
would charge $100 per hour of material for basic head-to-tail
transfer/cleanup. Roy

--
~ Roy
"If you notice the sound, it's wrong!"

[dave]

Hi Roy,

Thanks for responding. I'm pretty sure the hum is not buzz/harmonics. The
sound is pretty much pure 60 Hz to my ears. I am not sure of the original
format and track width (sorry am still learning the terminology). I guess
when I said side to side, I meant "height". I would imagine that you would
need a half-track machine to properly play back a half track tape? Is it
possible that the hum could be on the "fringes" in between the tracks and
that is what I am picking up mostly when I am playing the tape back on a 1/4
track machine? Is there a spec for the tape formats (mechanical drawings,
etc.)? I would like to understand this more from a visual sense of where
the tape head should be tracking in each case. And when did the various
formats first come into use? I imagine this tape to be from the late 1950's
to early 1960's. There is instrumental music on one "side" of the tape (ie
playing back in one direction on a stereo deck) and the voices that I'm
trying to get off the tape are on the other "side" of the tape (the other
direction). As far as I know, all of my machines are 1/4 track but the
Webcor (circa mid 1950's) possibly is not, although I am not able to get it
working just yet. Is there a way to tell just by looking at the heads
themselves?

thanks again,

Dave





"Roy W. Rising" > wrote in message
...
> "dave" > wrote:
> > Hello,
> >
> > I am not sure if this is a good forum for this inquiry, or if one
exists,
> > but here goes:
> >
> > I am trying to play back a very old open-reel tape recording for a
friend
> > of mine. It has some home recordings of deceased family members, etc.
> > So basically I am trying to do audio archiving for him. I own several
> > old open reel machines which generally have not seen much use to this
> > point and I am certainly no expert on the format.
> >
> > The problem I am having is that the audio in the track/tracks where the
> > voices are recorded has a severe 60 Hz hum over top of it. The hum is
> > very even in amplitude and is so strong that it sounds like it is
> > modulating the fairly faint voices underneath. I am recording to my
> > computer and have tried filtering the hum out with software but the
audio
> > is still garbled from the strong 60 Hz signal. I am thinking that the
> > head on the machine that was used to record these voice tracks was
> > aligned a little off to one side or something like that and that I might
> > be able to get a much cleaner take if I were able to move the head on
one
> > of my machines to align better with the track. I am not talking about
> > azimuth angle but actual side to side alignment. I am not sure if this
> > even makes sense but it is the only thing I could think of. If anybody
> > has a better idea on this topic, I would be most appreciative hearing
> > from you.
> >
> > thanks,
> >
> > Dave
>
> There are four adjustments that pertain to head allignment, "side to side"
> is not one of them. They are: Azimuth (gap perpendicularity to tape
> motion), Zenith (front/back tilt), Height (centering of gap to track) and
> Wrap (centering of gap to tape/head contact area). Azimuth is the most
> common misalignment problem, and usually is easy to handle.
>
> The 60Hz hum problem more likely is a "buzz" problem ... harmonics of the
> 60Hz hum. I don't know which software does the best job. The Roland 700
> Noise/Hum Eliminator is AD/DA digital hardware that does an amazing job.
> If, indeed, the 60Hz has modulated the speech, then there's not much that
> can be done.
>
> What is the track format of the tape, and about how long is it. I'm set
up
> to clean and digitize 7.5- and 15 ips half- and full track 1/4" tape. I
> would charge $100 per hour of material for basic head-to-tail
> transfer/cleanup. Roy
>
> --
> ~ Roy
> "If you notice the sound, it's wrong!"

[dave]

Hi Scott,

Tahnks for responding. I am not sure of the format, or of the formats of
the machines I have. Where would I get the "Magna See", and does it have to
be applied to an "expendible" part of the tape (IE does it cause harm to the
audio) ?

thanks again,

Dave




"Scott Dorsey" > wrote in message
...
> In article >, dave >
wrote:
> >I am trying to play back a very old open-reel tape recording for a friend
of
> >mine. It has some home recordings of deceased family members, etc. So
> >basically I am trying to do audio archiving for him. I own several old
open
> >reel machines which generally have not seen much use to this point and I
am
> >certainly no expert on the format.
>
> First question: do you know if the tracks you have are matching the tracks
> of the original machine? If you have a half-track machine and there is a
> quarter-track tape and there is hum on the "other side" of the tape, you
> will get him.
>
> >The problem I am having is that the audio in the track/tracks where the
> >voices are recorded has a severe 60 Hz hum over top of it. The hum is
very
> >even in amplitude and is so strong that it sounds like it is modulating
the
> >fairly faint voices underneath. I am recording to my computer and have
> >tried filtering the hum out with software but the audio is still garbled
> >from the strong 60 Hz signal. I am thinking that the head on the machine
> >that was used to record these voice tracks was aligned a little off to
one
> >side or something like that and that I might be able to get a much
cleaner
> >take if I were able to move the head on one of my machines to align
better
> >with the track. I am not talking about azimuth angle but actual side to
> >side alignment. I am not sure if this even makes sense but it is the
only
> >thing I could think of. If anybody has a better idea on this topic, I
would
> >be most appreciative hearing from you.
>
> It's possible. Most tape machines have head height settings.
>
> Spraying Magna-See on the tape might help you figure out what is up.
> --scott
>
> --
> "C'est un Nagra. C'est suisse, et tres, tres precis."

[Mike Rivers]

dave wrote:

> The problem I am having is that the audio in the track/tracks where the
> voices are recorded has a severe 60 Hz hum over top of it. The hum is very
> even in amplitude and is so strong that it sounds like it is modulating the
> fairly faint voices underneath.

Have you verified that the hum is strictly in playback, or is it on the
recording? You can tell if it's recorded by applying some pressure to
the capstan (the shaft that the pince roller presses against) to slow
down the tape while it's playing. If the pitch of the hum goes down,
it's on the original recording. If it remains constant, you have
playback problems. You can of course slow down the playback by dragging
a finger on the supply reel, but given that this is old tape and you
may not be sure of the condition of the tape or the recorder, better
not to put excess tension on the tape.

If the tape deck has a headphone jack, listen on headphones to be sure
that the hum isn't a result of connecting it to your computer. You may
have a ground loop problem. While this may not be simple to fix, it
will tell you where and where not to look.

Head alignment should be optmized, but the worst case mismatch will be
about a 6 dB lower playback level than optimum. From your description,
the problem is much worse than that. It's possible that you're just
dealing with crappy recordings and you'll have to resort to using
cleanup tools in your DAW to improve things. But try to eliminate
obvious problems first.

[Scott Dorsey]

In article >, dave > wrote:
>
>Tahnks for responding. I am not sure of the format, or of the formats of
>the machines I have. Where would I get the "Magna See", and does it have to
>be applied to an "expendible" part of the tape (IE does it cause harm to the
>audio) ?

No, it's just powdered iron in a light vehicle. I think Tape Warehouse sells
"Kyread brand magnetic visualization fluid" which is basically the same stuff
as Magna-See. It's an easy way to see what the format is, and if there is
profound 60 Hz hum on the track you will see the periodic ripples in the
thing.
--scott

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

[Roy W. Rising]

Dave ~ The Webcor most likely is a half track machine. The gap area of the
head will be just a little less than 1/8" tall. You can see some diagrams
at http://www.lochness.com/pltref/tapetype/tapetype.html .

1/4 track stereo came in around 1960. If the tape is half track, then a
quarter track head typically will scan the upper part of the track. There
is little liklihood that the hum is not on the actual track. A half track
head will improve the signal-to-noise ratio by scanning all of the
available information. However, if that includes the hum, then there will
be no real improvement.

I suspect that if you are able to get rid of the 60Hz sufficiently and the
voices remain modulated/garbled, then there's not much more that can be
done. Roy

"dave" > wrote:
> Hi Roy,
>
> Thanks for responding. I'm pretty sure the hum is not buzz/harmonics.
> The sound is pretty much pure 60 Hz to my ears. I am not sure of the
> original format and track width (sorry am still learning the
> terminology). I guess when I said side to side, I meant "height". I
> would imagine that you would need a half-track machine to properly play
> back a half track tape? Is it possible that the hum could be on the
> "fringes" in between the tracks and that is what I am picking up mostly
> when I am playing the tape back on a 1/4 track machine? Is there a spec
> for the tape formats (mechanical drawings, etc.)? I would like to
> understand this more from a visual sense of where the tape head should be
> tracking in each case. And when did the various formats first come into
> use? I imagine this tape to be from the late 1950's to early 1960's.
> There is instrumental music on one "side" of the tape (ie playing back in
> one direction on a stereo deck) and the voices that I'm trying to get off
> the tape are on the other "side" of the tape (the other direction). As
> far as I know, all of my machines are 1/4 track but the Webcor (circa mid
> 1950's) possibly is not, although I am not able to get it working just
> yet. Is there a way to tell just by looking at the heads themselves?
>
> thanks again,
>
> Dave

--
~ Roy
"If you notice the sound, it's wrong!"

[[email protected]]

dave > wrote:
: I am recording to my computer and have tried filtering the hum out
: with software but the audio is still garbled from the strong 60 Hz signal.

Did you filter by using an equalizer, or by sampling the hum and
subtracting it? If the hum is as pure as you say, sampling it
(preferably at the beginning or end of the tape, before or beyond
the source material if possible) and then subtracting say, 80% of it,
ought to render the source material pretty clear, albeit with some artifacts.

Unless the hum is extremely loud, then neither way will help much.
I agree you need to verify that it's on the tape and not in the playback.

Scott

[Scott Dorsey]

> wrote:
>dave > wrote:
>: I am recording to my computer and have tried filtering the hum out
>: with software but the audio is still garbled from the strong 60 Hz signal.
>
>Did you filter by using an equalizer, or by sampling the hum and
>subtracting it? If the hum is as pure as you say, sampling it
>(preferably at the beginning or end of the tape, before or beyond
>the source material if possible) and then subtracting say, 80% of it,
>ought to render the source material pretty clear, albeit with some artifacts.

Unfortunately the repeating-waveform removal tools can have some trouble
because there's usually a lot of flutter on those consumer tapes. It
can be easier to just an equalizer and either widen the filter a little bit
or just baby the thing along, nulling by ear.

>Unless the hum is extremely loud, then neither way will help much.
>I agree you need to verify that it's on the tape and not in the playback.

I'm going by the assumption that it's on the tape. If it's in playback,
that's a whole other issue.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[[email protected]]

Scott Dorsey > wrote:
: Unfortunately the repeating-waveform removal tools can have some trouble
: because there's usually a lot of flutter on those consumer tapes.

True, but if he hasn't tried it, he should (I think).

- Scott (not the real one)

[Adrian Tuddenham]

Mike Rivers > wrote:

> dave wrote:
>
> > The problem I am having is that the audio in the track/tracks where the
> > voices are recorded has a severe 60 Hz hum over top of it. The hum is very
> > even in amplitude and is so strong that it sounds like it is modulating the
> > fairly faint voices underneath.
>
> Have you verified that the hum is strictly in playback, or is it on the
> recording?

Just a really basic point, is the oxide side of the tape facing the
head?

--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

[Scott Dorsey]

> wrote:
>Scott Dorsey > wrote:
>: Unfortunately the repeating-waveform removal tools can have some trouble
>: because there's usually a lot of flutter on those consumer tapes.
>
>True, but if he hasn't tried it, he should (I think).

Yeah, it certainly won't hurt. Too many folks expect miracles from NR tools,
though.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Carey Carlan]

(Adrian Tuddenham) wrote in
alid.invalid:

> Mike Rivers > wrote:
>
>> dave wrote:
>>
>> > The problem I am having is that the audio in the track/tracks where
>> > the voices are recorded has a severe 60 Hz hum over top of it. The
>> > hum is very even in amplitude and is so strong that it sounds like
>> > it is modulating the fairly faint voices underneath.
>>
>> Have you verified that the hum is strictly in playback, or is it on
>> the recording?
>
> Just a really basic point, is the oxide side of the tape facing the
> head?

Yes, the oxide is on the head side so it can be as close to the head as
possible for maximum output.

Next question. Do you hear the hum from headphones attached to the tape
recorder when the computer is not attached? If the answer is No, do you
have the computer and the tape recorder plugged into the same power outlet.
If not, make it so. The hum could be a simple ground loop.

[martin griffith]

On 21 Aug 2006 13:47:25 -0400, in rec.audio.pro
(Scott Dorsey) wrote:

>In article >, dave > wrote:
>>
>>Tahnks for responding. I am not sure of the format, or of the formats of
>>the machines I have. Where would I get the "Magna See", and does it have to
>>be applied to an "expendible" part of the tape (IE does it cause harm to the
>>audio) ?
>
>No, it's just powdered iron in a light vehicle. I think Tape Warehouse sells
>"Kyread brand magnetic visualization fluid" which is basically the same stuff
>as Magna-See. It's an easy way to see what the format is, and if there is
>profound 60 Hz hum on the track you will see the periodic ripples in the
>thing.
>--scott

FYI, but you probably know this anyway :-)
http://richardhess.com/notes/2006/03/08/magnetic-developers-seeing-the-tracks/


martin