[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

[Walt]

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.


The first thing to determine is if the 60hz hum is actually on the tape,
or whether it's being induced at playback, either through the playback
head picking up some stray field, or due to a ground loop connecting the
deck to the speakers.

Hopefully, it's the latter - disconnect the tape machine from the
computer, and take it to another room. If the hum changes, it's
probably an artifact of playback.

If it's the former (it's actually on the tape) all you can do is
transfer the material to the computer and use some noise abatement software.

//Walt

[Serge Auckland]

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


Firstly, I assume you have tried the tapes on different machines, and
the hum isn't coming from the replay machine.

Moving the head vertically won't do anything much for the hum, it will
only increase output slightly, and reduce crosstalk from the track
coming the other way. (I assume these tapes are not stereo).

The hum is best removed with a tunable sharp null filter, but you will
probably need one at 120Hz and 180Hz to catch the mains harmonics, as
the chances are that the mains hum isn't pure 60Hz. These tracking
filters are available to the professional market, but I don't know of
anything on the consumer market. Ebay may be a possibility, or try and
rent one for the day from your local pro rental dealer. There should be
one or more in most large cities. Finally, depending on how valuable
these recordings are to you or your friend, you could pay for
professional restoration which will extract the maximum available, but
won't be cheap.

Hope this helps, but it *is* a difficult problem.

S.

[James Lehman]

"dave" wrote in message
...
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



The first thing to do is verify if the hum is actually part of the
recording. It might be coming from the playback. If there is no way to get a
cleaner take into your computer, then you might want to consider using a
more progressive noise reduction technique. There are some programs out
there that can analyze a section of the unwanted noise, from a part of the
recording that has no wanted signal. It can then use this noise signature to
remove the noise from the rest of the recording. This is not the same as
filtering out the hum.

James. )

[Laurence Payne]

On Mon, 21 Aug 2006 16:09:52 GMT, "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.

Check the hum is actually on the tape. It might be coming from the
recorder, either from an earth loop or because an old machine has
dried-out capacitors or another fault.