If the tapes were stored in the same place, it could be that they were near
a magnetic source that imprinted the crackle on all of them - I had some
cassettes stored for years near a power source and they all eventually had
the same "bup" sound intermittently as they unspooled.

Dave W.

-----Original Message-----
From: Association for Recorded Sound Discussion List
[mailto:[log in to unmask]] On Behalf Of Mike Hirst
Sent: Thursday, September 18, 2008 10:17 AM
To: [log in to unmask]
Subject: Re: [ARSCLIST] cassette crackle

The tapes have been recorded by many different people at different 
locations using different equipment. The crackle seems to follow no set 
pattern, other than if it is evident on one side of the tape it'll 
usually be found on the other. Although if the tape has been recorded 
one side only, there is no crackle on the unrecorded section of tape.

I know that some of the tapes I am working with have been copied from 
other sources, both open reel and cassette and at least one of the 
machines used to copy the tapes has a problem which results in 
intermittent drop out on the rh channel. This could be a loose cable, 
faulty mic, or an open reel tape recorded using a four track stereo 
recorder, but played back using a two track mono deck. I have no way of 

I suspect that the crackle is the result of either poor quality 
recording or poor quality tape to tape transfer. The crackle looks the 
same on the spectral frequency display. I can't rule out the possibility 
that there could be some common factor in the equipment used to record 
or copy the tapes. (They are all currently held as part of the same 

Tom Fine wrote:
> Were these tapes all recorded by the same person on the same system? If 
> so, it's probably something intermitent (sp?) in the original recording 
> chain -- a dirty connector or the like. If they are off-air recordings 
> from the radio, any number of atmospheric and in-house electrical things 
> can cause crackles. If they are, for instance, Grateful Dead concert 
> recordings made off a common buss from the mixing console or even from a 
> shared mic array, anything from connector-itis to electrical spikes to 
> things happening on-stage can cause crackles. And of course, if they are 
> from LPs or other grooved disks, that could just be surface problems.
> -- Tom Fine
> ----- Original Message ----- From: "Mike Hirst" 
> <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Thursday, September 18, 2008 8:53 AM
> Subject: [ARSCLIST] cassette crackle
>> 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?
>> -- 
>> Mike Hirst
>> Managing Director
>> DAS-360
>> 16 Ocean View
>> Whitley Bay
>> Tyne & Wear
>> NE26 1AL
>> tel: 0191 289 3186
>> email: [log in to unmask]
>> web:

Mike Hirst
Managing Director
16 Ocean View
Whitley Bay
Tyne & Wear
NE26 1AL

tel: 0191 289 3186
email: [log in to unmask]