Cassettes recorded on one deck sound bad on another - Why?
Stefan Wrobel
I would be very grateful for any advice on the following
problem: I would like to be able to listen to my analog
cassette tapes on two different recorders (in different
places). Unfortunately, tapes recorded on one recorder,
with perfect sound when played back on that same recorder,
sound bad (high frequency losses) when played on the other.
Is there anything that can be done to make the two
machines compatible? Is this related to the azimuth position
of the heads, or are there other factors?
Any hints would be greatly appreciated ...
Ciao,
Stefan.
--
Dr. Stefan Wrobel, GMD (German Natl. Research Center for Comp. Science)
FIT.KI (Artificial Intelligence Research Division)
Schloss Birlinghoven, 53754 Sankt Augustin, Germany
stefan...@gmd.de Fax: +49/2241/14-2889
Scott Givan
Schuster) wrote:
> In article <2r9uet$5...@hercules.gmd.de>,
> Stefan Wrobel <wro...@hercules.gmd.de> wrote:
> >Hi netters,
> >
> >I would be very grateful for any advice on the following
> >problem: I would like to be able to listen to my analog
> >cassette tapes on two different recorders (in different
> >places). Unfortunately, tapes recorded on one recorder,
> >with perfect sound when played back on that same recorder,
> >sound bad (high frequency losses) when played on the other.
> >Is there anything that can be done to make the two
> >machines compatible? Is this related to the azimuth position
> >of the heads, or are there other factors?
>
> The reason is most likely that one, or both decks' tape heads are out of
> alignment. When the tape head azimuth is off, the immediate noticeable
> effect is loss of highs. Record a test tape on each, and play both tapes
> on a third deck (friends?) that is known to be in alignment. Whichever
> tape sounds bad ... get the deck which recorded that tape serviced.
>
> Be aware that if realigning the deck changes the azimuth a lot, all of
> your old tapes will sond that way too; but the new ones will b`playback
> properly.
>
I don't think that one deck can be "out of alignment", because we don't
know what that deck was aligned to at the factory. I don't believe there
is an industry standard for aligning tape deck heads. This means that tape
decks from different manufacturers probably have different alignments
relative to each other, but neither is "out of alignment". This could also
probably occur in tape decks from the same manufacturer; for example, if
the two decks were manufactured at significantly different dates. The best
solution for the above problem would be to have the two tape decks in
question aligned to each other. Then a tape made on one deck should have
the best chance to sound the same on the other deck.
Scott Givan
gi...@molbio.uoregon.edu
Michael Schuster
Scott Givan <gi...@molbio.uoregon.edu> wrote:
>>
>I don't think that one deck can be "out of alignment", because we don't
>know what that deck was aligned to at the factory. I don't believe there
>is an industry standard for aligning tape deck heads. This means that tape
>decks from different manufacturers probably have different alignments
>relative to each other, but neither is "out of alignment". This could also
>probably occur in tape decks from the same manufacturer; for example, if
>the two decks were manufactured at significantly different dates. The best
>solution for the above problem would be to have the two tape decks in
>question aligned to each other. Then a tape made on one deck should have
>the best chance to sound the same on the other deck.
Of course there is a standard, and there are standard reference tapes that
are used at the factory to align the tape head azimuth. Manufacturer,
date, or production run has absolutely nothing to do with the standard
that is SUPPOSED TO be followed.
If you align both decks to each other, and one of them deviates from the
standard, then all you accomplish is to make two decks that are incapable
of recording or playing tapes for/from any other properly aligned decks.
--
Mike Schuster | schu...@panix.com | 70346...@CompuServe.COM
------------------- | schu...@shell.portal.com | GEnie: MSCHUSTER
Scott Givan
Schuster) wrote:
>
> Of course there is a standard, and there are standard reference tapes that
> are used at the factory to align the tape head azimuth. Manufacturer,
> date, or production run has absolutely nothing to do with the standard
> that is SUPPOSED TO be followed.
>
> If you align both decks to each other, and one of them deviates from the
> standard, then all you accomplish is to make two decks that are incapable
> of recording or playing tapes for/from any other properly aligned decks.
>
Then why do two new tape decks from different manufacturers sound different
when they play a tape made on the opposite machine. Individual
manufacturers may have internal standards they try to maintain with respect
to head azimuth alignment, but I don't believe there is an industry
standard. If there is, tape deck manufacturers don't adhere very
rigoroulsy to them. It also seems that pre-recorded tape manufacturers
would desire to adhere to these standards so that consumers would enjoy
their products more. My experience is that sound quality with pre-recorded
tapes is a crap-shoot; the same tape sounds marginally acceptable on some
decks and terrible on others, new or old. Again, if there is an industry
standard, it is not observed rigorously.
Scott Givan
Eric Gunnerson
>Then why do two new tape decks from different manufacturers sound different
>when they play a tape made on the opposite machine. Individual
Differences in bias? Differences in azimuth over the years?
>manufacturers may have internal standards they try to maintain with respect
>to head azimuth alignment, but I don't believe there is an industry
>standard. If there is, tape deck manufacturers don't adhere very
>rigoroulsy to them.
I would guess that virtually all tape decks are well aligned when they
leave the factory. Over time, that alignment can change - which is why
there are standard alignment tapes that let you adjust the azimuth so
that it is correct.
It also seems that pre-recorded tape manufacturers
>would desire to adhere to these standards so that consumers would enjoy
>their products more. My experience is that sound quality with pre-recorded
>tapes is a crap-shoot; the same tape sounds marginally acceptable on some
>decks and terrible on others, new or old. Again, if there is an industry
>standard, it is not observed rigorously.
Pre-recorded tapes are sold for profit. They use cheap tape and cheap
shells. Fidelity is not one of their major concerns.
>Scott Givan
--
Eric Gunnerson
gunn...@halcyon.com
Michael Schuster
Scott Givan <gi...@molbio.uoregon.edu> wrote:
>
>
>Then why do two new tape decks from different manufacturers sound different
>when they play a tape made on the opposite machine.
There are gazillions of things in the design and construction of an audio
device which can affect how it sounds. Why do you invoke tape head azimuth
in the above argument?
>Individual
>manufacturers may have internal standards they try to maintain with respect
>to head azimuth alignment, but I don't believe there is an industry
>standard.
Whether or not you believe it, there is. Look at the service manuals for
the equipment you own. For Japanese manufacturers, that standard is
usually the TEAC MTT-114N calibration tape, or its successor.
In a more general sense, there is an absolute standard. The magnetic head
gap is perpendicular to the edge of the tape. That's it.
>If there is, tape deck manufacturers don't adhere very
>rigoroulsy to them. It also seems that pre-recorded tape manufacturers
>would desire to adhere to these standards so that consumers would enjoy
>their products more. My experience is that sound quality with pre-recorded
>tapes is a crap-shoot; the same tape sounds marginally acceptable on some
>decks and terrible on others, new or old. Again, if there is an industry
>standard, it is not observed rigorously.
I agree with the above. The discrepancies you note, in fact, were one of
the reaosny why Dolby C failed for pre-recorded tapes. The minor
differences in tape head azimuth were enough, given the higher compression
in Dolby C vs. B, to make many tapes unlistenable.
The underlying error in your thinking is the assumption that the compact
audio casette is a high fidelity recording medium. Face it: it ain't.
It was never designed to be.
Jamie Hanrahan, Kernel Mode Systems
> I don't think that one deck can be "out of alignment", because we don't
> know what that deck was aligned to at the factory. I don't believe there
> is an industry standard for aligning tape deck heads.
Um, your eagerness to contribute to the discussion is commendable, but perhaps
you would have a more positive overall effect if you confined your
contributions to areas of which you have some knowledge.
There most certainly is such a standard. Teac, Magnetic Reference Labs, BASF,
and others will happily sell you alignment tapes, and they do agree with one
another.
--- Jamie Hanrahan, Kernel Mode Systems, San Diego CA
Internet: j...@cmkrnl.com (JH645) Uucp: uunet!cmkrnl!jeh CompuServe: 74140,2055
Scott Givan
Mike Schuster wrote:
There are gazillions of things in the design and construction of an audio
device which can affect how it sounds. Why do you invoke tape head azimuth
in the above argument?
Whether or not you believe it, there is (an industry standard). Look at the
service manuals for the equipment you own. For Japanese manufacturers, that
standard is usually the TEAC MTT-114N calibration tape, or its successor.
In a more general sense, there is an absolute standard. The magnetic head
gap is perpendicular to the edge of the tape. That's it.
My Naive reply:
Maybe my example is confusing, I'll try again. Say you make a recording on
deck 1. When you play back the recording on deck 1, it sounds fine. When
you play back the recording on deck 2, it sounds bad; probably lacking high
frequencies. Now you make a recording on deck two. When you play back
this recording on deck 2 it sounds fine. When you play back this recording
on deck 1 it has poor high frequency reproduction. Since both recordings
sound fine on the decks that made them, I don't think it is a bias,
head-gap width, or head composition discrepency that is causing the poor
reproduction. It seems that it is probably an azimuth difference between
the two decks. I am trying to remember to what level an azimuth difference
becomes audible; I remember a figure such as 1/20 of 1 degree of arc
difference with respect to the perpendiculariy of the tape head to the tape
surface causes a dramatic decrease in high frequency reproduction. I
cannot expect someone working in a Sony plant to be able to consistently
calibrate every tape deck to this level of precision. Granted, I have no
experience working in such an environment, but that expectation seems
unreasonable. I do have some experience in using various brands of tape
decks. I have noticed marked differences in individual tape decks'
abilities to accurately play tapes that sound fine on the deck that made
the tape. In many cases, I have cleaned and demagnitized the decks before
listening to them. The decks have been new and old. There has been
definite differences in playback accuracy. This has caused me to believe
that an industry standard for azimuth is not rigorously upheld.
Scott Givan
Jamie Hanrahan, Kernel Mode Systems
> In article <2rbhq6$f...@panix2.panix.com>, schu...@panix.com (Michael
> Schuster) wrote:
>>
>> Of course there is a standard, and there are standard reference tapes that
>> are used at the factory to align the tape head azimuth. Manufacturer,
>> date, or production run has absolutely nothing to do with the standard
>> that is SUPPOSED TO be followed.
>
> when they play a tape made on the opposite machine.
Read his second sentence above. The answer is, the manufacturers are sloppy.
> Individual
> manufacturers may have internal standards they try to maintain with respect
> to head azimuth alignment, but I don't believe there is an industry
> standard.
You're wrong.
> If there is, tape deck manufacturers don't adhere very
> rigoroulsy to them.
Now you've got it.
David Breneman
: In article <2raek9$n...@panix2.panix.com>, schu...@panix.com (Michael
: Schuster) wrote:
:
: > In article <2r9uet$5...@hercules.gmd.de>,
: > Stefan Wrobel <wro...@hercules.gmd.de> wrote:
: > >with perfect sound when played back on that same recorder,
: > >sound bad (high frequency losses) when played on the other.
: > >Is there anything that can be done to make the two
: > >machines compatible? Is this related to the azimuth position
: > >of the heads, or are there other factors?
: >
: > The reason is most likely that one, or both decks' tape heads are out of
: > alignment. When the tape head azimuth is off, the immediate noticeable
: > effect is loss of highs.
: I don't think that one deck can be "out of alignment", because we don't
: know what that deck was aligned to at the factory. I don't believe there
: is an industry standard for aligning tape deck heads.
Yes, there is! It's called "vertical". :-)
: This means that tape
: decks from different manufacturers probably have different alignments
: relative to each other, but neither is "out of alignment". This could also
: probably occur in tape decks from the same manufacturer; for example, if
: the two decks were manufactured at significantly different dates. The best
: solution for the above problem would be to have the two tape decks in
: question aligned to each other. Then a tape made on one deck should have
: the best chance to sound the same on the other deck.
ARGGGH! *Never* align decks against each other! Align them against a
reference standard. I'm sorry, gi...@molbio.uoregon.edu, but you're
just *making this up as you go along*. You can align a cassette deck
head in a couple minutes for the cost of a non-magnetic screwdriver
and a reference tape. Then, your tapes will sound their best on *all*
other decks, not just ones adjusted to your "custom alignment standard".
--
David Breneman Email: da...@jaws.engineering.dgtl.com
System Administrator, Voice: +1 206 881-7544 Fax: +1 206 556-8033
Product Development Platforms
Digital Systems International, Inc. Redmond, Washington, U. S. o' A.
Michael Schuster
>
>I would be very grateful for any advice on the following
>problem: I would like to be able to listen to my analog
>cassette tapes on two different recorders (in different
>places). Unfortunately, tapes recorded on one recorder,
>with perfect sound when played back on that same recorder,
>sound bad (high frequency losses) when played on the other.
>Is there anything that can be done to make the two
>machines compatible? Is this related to the azimuth position
>of the heads, or are there other factors?
The reason is most likely that one, or both decks' tape heads are out of
alignment. When the tape head azimuth is off, the immediate noticeable
effect is loss of highs. Record a test tape on each, and play both tapes
on a third deck (friends?) that is known to be in alignment. Whichever
tape sounds bad ... get the deck which recorded that tape serviced.
Be aware that if realigning the deck changes the azimuth a lot, all of
your old tapes will sond that way too; but the new ones will b`playback
properly.
--
rsan...@alb.asctmd.com
If the decks have never been aligned since they were purchased that is the
reason they sound different.
The vast majority of cassette decks use spings to support the heads.
Springs sag over time. Additionally, the overall construction of the deck
determines its stability over time. A deck using a cast head support will be
more stable than one using a stamped head support.
Cassette decks, in home use, should be aligned every year. If they aren't
then tapes recorded on them will not sound the same a year later.
Alignment using a known calibration tape either first generation -- MRL or
second is a very repeatable event. Where things get fuzzy and start to fall
apart is when the equalization is adjusted.
Everytime a tape passes over a head some of the particles come off.
Manufactures of calibration tapes know this and provide some peaking of 1 to 3
dB to extend the lifetime of the calibration tape. Even so a good tech will
know how many times the calibration tape has been used and can compensate for
the treble loss during the equalization adjust procedure. (Usally, the tape
will settle down after 3 passes and will have exhibited only a 2 dB loss.)
As for the standard, Phillips created the cassette deck and defined all the
standards , including the ones for alginment. Others, as they refined the
format made some modifications due to increased capability --- i.e. response
beyond 10 KHz.
Bob
Graeme Gill
>the treble loss during the equalization adjust procedure. (Usally, the tape
>will settle down after 3 passes and will have exhibited only a 2 dB loss.)
Hmm. In testing a number of blank tapes a while ago, I
noticed that the tape HF response actually improved after
2 or 3 record/play cycles. I didn't test whether HF response
improved for a while or not in a record/play/play/play type
of usage.
Graeme Gill.
rsan...@alb.asctmd.com
>Hmm. In testing a number of blank tapes a while ago, I
>noticed that the tape HF response actually improved after
>2 or 3 record/play cycles. I didn't test whether HF response
>improved for a while or not in a record/play/play/play type
>of usage.
Graeme,
The possibility exists if the tapes were poorly polished at the factory.
This commonly results in a lot of oxide being removed from the surface
and being deposited on the heads and transport. (This used to be a big
problem with Maxell reel-to-reel tapes.)
Or you may have had dirty heads that got cleaned by the leader?
The reason for treble loss from new tapes is a loss of material from the
tape due to friction. A treble increase occurs due to better tape-to-head
contact, or a change in the equalization and/or bias (at the expense of
distortion).
Bob
Graeme Gill
>In article <graeme.769669007@labtam> gra...@labtam.labtam.oz.au (Graeme Gill) writes:
>>Hmm. In testing a number of blank tapes a while ago, I
>>noticed that the tape HF response actually improved after
>>2 or 3 record/play cycles. I didn't test whether HF response
>>improved for a while or not in a record/play/play/play type
>>of usage.
> The possibility exists if the tapes were poorly polished at the factory.
I doubt that all 10 or so different manufacturers tapes I was
testing (Including the most expensive to the cheapest I could
get, normal, chrome and metal tapes) were poorly polished.
>This commonly results in a lot of oxide being removed from the surface
>and being deposited on the heads and transport. (This used to be a big
>problem with Maxell reel-to-reel tapes.)
I've come across bad batches on occasions (That's why I've given
up on TDK tapes - poor quality control in my experience)
> Or you may have had dirty heads that got cleaned by the leader?
The heads aren't worn, nor were they dirty.
> The reason for treble loss from new tapes is a loss of material from the
>tape due to friction. A treble increase occurs due to better tape-to-head
>contact, or a change in the equalization and/or bias (at the expense of
>distortion).
I assume that the improvement in treble response (and a noticeable
decrease in drop out rate) was due to the heads polishing and cleaning
the tape, and the tape shaping itself to the profile of the heads.
The bias and equalization is not relevant, as I was in the process
of manually adjusting the bias for each tape and measuring sensitivity
and saturation characteristics over the audio band with the record
equalizer disconnected. [I was actually doing this in order to
re-design the auto bias adjustment and the record equalizer
circuit.]
Graeme Gill.