There are many "it depends" factors in this discussion--it seems nothing
is ever as simple as it looks.
For case (1), playing a mono half-track open-reel tape on a stereo
machine and reversing the channel playing in reverse, I do this all the
I think the reason Tom Fine finds it sounds different is that not only
do you need to reverse the DIRECTION of the recording, you also need to
reverse the POLARITY (aka phase) of the digital file. The attack times
and group delay of the filters may be a factor, but the reason Tom
mentions about attack times is far more important with Dolby and dbx and
similar noise reduction systems. I would never run a Dolby or dbx decode
As to azimuth, this works best in a case where the tape was recorded
sequentially with side two immediately following side one on the same
recorder. In this case, any azimuth mis-adjustment will be very close to
identical on both side (tracks) of the tape. If you draw out a gross
error, you'll see that it ends up working.
Tom's point about poor guidance of the tape, where the tape is skewed,
could diminish the accuracy of that. The poor guidance in either record
or reproduce modes could mess this up. You just have to check.
For case (2), which I'd like to call "playing full-track tapes" there
are many factors to consider.
The two greatest factors in making the decision to use a full-track head
or something narrower are:
(a) Tape guidance accuracy
These two combine to generate a combing effect that varies as the tape
I found that it was a toss-up whether I liked the NAB 82 mil track width
or the full-track (~240 mil) heads on the Studer A810 at 7.5 in/s. In
some cases, the full-track heads gave more combing than I would like,
while in others, the full-track heads were fine.
Since I have obtained a Studer A80RC with full-track heads, I have never
found a 7.5 in/s tape that didn't sound gorgeous (or as gorgeous as it
was recorded) with the full-track head.
I have not done extensive testing on the Sony APR-5000 for this.
HOWEVER you WILL know when the combing issue is a problem with your
tapes on your machine (it sounds spacey and it comes and goes).
The A80 has played some pretty rough tapes, including one that earned me
this comment (posted on my website with permission):
/*This sounds superb. Much better than I ever could have anticipated.
Thank you! Also, you should realize that this is an important recording.
We are thrilled you were able to capture it.*/
--- Hannah Frost, Preservation Librarian for Digital and Media
Collections, Stanford University Libraries --- Referring to a damaged
full-track 7.5 in/s tape from the 1975 Monterey Jazz Festival.
You might find using a DIN stereo head with a 105 mil track width to be
a viable alternative. I discuss the differences between the NAB and DIN
heads from the perspective of stereo tapes, but you can extrapolate to mono.
The other thing we fight with a narrower-than-recorded repro head is
fringing where more bass gets picked up than it should. This is another
disadvantage of the narrower heads.
So, the bottom line is IF YOU CAN, ALWAYS use a full-track head for
playing full-track tapes.
As a corollary, always use a DIN STEREO head for playing DIN STEREO tapes.
As another corollary, always use an NAB STEREO head for playing NAB
I don't think the differences in NAB STEREO heads (from 75 to 82 mil --
Studers are about 79 mil, Ampex 75 mil, and "NAB Standard" are 82 mil)
requires matching to that degree.
On 2012-01-05 9:53 PM, Gregorio Garcia Karman wrote:
> Dear list,
> considering the possibility of the following compromising solutions in the digital transfer of open reel tapes...
> 1. playing a mono half-track open reel tape on a stereo machine and reversing the channel playing in the wrong direction digitally.
> 2. playing a full-track mono tape on a stereo machine.
> ...what are the considerations that speak against those?
> Thanks for your advice
Richard L. Hess email: [log in to unmask]
Aurora, Ontario, Canada (905) 713 6733 1-877-TAPE-FIX
Quality tape transfers -- even from hard-to-play tapes.