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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.

dl

> 
> ----- Original Message ----- From: "David Lennick" <[log in to unmask]>
> To: <[log in to unmask]>
> 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.
>>
>> dl
>>
>> 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.
>>>
>>> http://www.mikehirst.netfirms.com/audio/rhclick.wav
>>>
>>> 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: [log in to unmask]
>>>> 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.
>>>>
>>>
>>
> 
>