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Re: [ARSCLIST] cassette crackle

Yes, read the previous posts after I sent mine.

Wow, this crackle thing poses a real "which evil is worse" choice in the case of some old tapes similar to what I've run across. The outer part of the mono track, which shouldn't have the clicks and clacks (left channel) can sometimes be badly warped/crinkled. Then you have to decide, which sounds worst and suffer one or the other. I would suggest that in many cases, especially with the kind of low-quality spoken-word content usually found on these kinds of cassettes, better to take the click/clack right channel and de-click it with DSP software. There is also a certain (relatively small) amount of click/clack that is not going to hamper playback intelligability on low-quality spoken-word recordings.

-- Tom Fine

----- Original Message ----- From: "David Lennick" <dlennick@xxxxxxxxxxxx>
To: <ARSCLIST@xxxxxxxxxxxxxxxx>
Sent: Thursday, September 18, 2008 5:53 PM
Subject: Re: [ARSCLIST] cassette crackle

Tom Fine wrote:
Hi David:

Why does this happen? What is different about the mono deck?

-- Tom Fine

Pretty well covered by recent posters. Incidentally, we had a similar problem with tapes made on our ancient Utah tape recorder (full track, bought in 1950). When we began copying the tapes made on that machine over to the Wollensak in 1959, anything recorded prior to 1955 had to be copied from another Wollensak because repeated repairs to the Utah had resulted in its running fast (about 8 IPS) and the tapes were noisy and cruddy sounding after a certain point, probably because of head wear. We didn't have a quarter-track machine yet so we were too dumb to know that we'd get better results from the right channel or down the middle of the tape track.


----- Original Message ----- From: "David Lennick" <dlennick@xxxxxxxxxxxx> To: <ARSCLIST@xxxxxxxxxxxxxxxx> Sent: Thursday, September 18, 2008 11:19 AM Subject: Re: [ARSCLIST] cassette crackle

Dumb question (for various reasons, I can't listen to the file at the moment). Were these cassettes all recorded on small mono portable machines? Tapes made on these almost always have a crackly or noisy right channel when played back on good decks and in stereo. The solution here is simply to play only the left channel.


Mike Hirst wrote:
Thanks Richard,

your advice is, as ever, well informed sagely and intelligent. I suspect that I'm not going to find a definitives answer here, but for your interest, and for anyone else who may be interested, I've posted a 10sec (wav) clip of the kind of crackle I'm hearing. this sort of thing will continue through the full length of the recording and can be heard when the tape is played back using multiple recorders, all of which have been tested using other tapes, which exhibit no such problems.


filesize= 1392640 byte(s)
riffsize= 1764036 byte(s)
format  = Straight-PCM
channel = 2
depth   = 16 bit(s)
blk.size= 4 byte(s)
smp.rate= 44100 Hz
samples = 441000
playtime= 0:10.010

you will note from the clip that the crackle can only be heard in the rh channel. this is typical of the phenomenon, but it can sometimes be heard in both channels (with a bias towards the rh ch).

I have experimented with some of the de-crackle filters I use when working with disc transfers and as Richard suggests, the crackle can be removed, I am however curious as to where the crackle comes from.

Richard L. Hess wrote:
Hello, Mike,

Tom Fine has already posted a number of good explanations.

There are, however, less-common explanations that you may wish to be aware of, just in case.

(1) If there is a mismatch between the record machine record and erase head track position, perturbations in the record bias and/or erase MAY print to a tape like this. DC-(i.e. permanent magnet) erase may also cause something like this, but it is usually more of a "burbling" or what is sometimes called "rocks".

(2) Static electricity and PLAYBACK machine "glitches" CAN print to a tape without the recorder being in record mode. It's uncommon (thankfully), but it can happen. Static can be generated by fast winding in a very dry environment, and depends on cassette materials including the shell and slip sheets. This is more prevalent with reels than cassettes.

This clicks can usually be removed (depending on their source) by a declick/decrackle plug-in for your favourite DAW. The Magix restoration tools version of this is the best I've yet owned, but I haven't owned either DC7 nor the high-end Algorithmix version.

At 08:53 AM 2008-09-18, Mike Hirst
Here's a thing that's been confusing me for some time. I have spent the past six months working my way through a large number of cassette tapes mostly recorded between 1985 and 1995. every now and again I notice light, but significant crackling. This is often more noticeable in the right channel, but not exclusively so. On some recordings this is louder, on most recordings this is not evident at all. This is not restricted to any one brand of cassette, nor is it associated with any one playback machine and/or soundcard. Can anyone explain this for me?

Richard L. Hess email: richard@xxxxxxxxxxxxxxx Aurora, Ontario, Canada (905) 713 6733 1-877-TAPE-FIX Detailed contact information: http://www.richardhess.com/tape/contact.htm Quality tape transfers -- even from hard-to-play tapes.

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