Help Minimizing Stretched Tape WaWa

Hi All –

I’m on a Windows 7 Pro laptop using up-to-date Audacity 2.2.2.

Using Audacity several years ago I recorded both sides of my cassette The Beatles Concerto” (Royal Liverpool Philharmonic Orchestra, Rostal & Schaefer, Ron Goodwin) and exported the cassette’s sides as two mp3’s. I now want to break the large files into the various movements but discover that the tape had stretched during long storage and there is a very noticeable “wa wa” effect toward one end of both recordings.

This “album” was never issued as a CD (except in Japan) and I have not been able to find a source where I could purchase a digital download. Audacity’s magical effects have pulled my butt out of the fire many many times and I’m hoping there might be an effect which will maybe analyze my two tracks and “fix” the mangled tempo where necessary.

I’ll welcome any discussion! Thanks! Jim in Maine

Audacity has a time track tool which can (manually) correct changes in speed.
If you want to correct it automatically, you’ll need other software, e.g.

I found this copy on Amazon:

and then fell off my chair when I saw the price tag …

So I can see why you might want to rescue your tape.

Are you sure it is a stretched tape and not poor tape transport which is making the tape slip?

This page from the Audacity Wiki has some useful tips on sorting out a tape deck:
(I had my Nakamichi professionally serviced before I converted my cassette tapes).


Hey Trebor and WC -

Thank you for your replies. My brother has been doing a lot of “cassette ripping” recently. I’ll dig out the cassette and take it over to him. We can do some of the suggested re-tensioning, etc before attempting to re-record. Thank you for pointing out Audacity’s assets/suggestions on the subject …just when does Audacity cease to surprise?

My “WaWa” (I will have to switch to calling it “wow and flutter”) problems could certainly be due to transport troubles. Most of the stretched tapes I have run into were long 120 minute cassettes I had recorded myself. My understanding is that the 90 and 120 minute tapes were constructed using physically thinner tape = more susceptible to stretching.

Boy! I got excited when I saw Celemony Capstan. It would appear that Capstan would set things straight pretty quickly. But, the price is a real stopper. US$200.00 just to RENT it for 5 days. OUCH!

I’m thinking that my best hope is to find someone who has a digital recording of the album. The fact that I have purchased the music relaxes my worry of possibly committing an illegal act. I’m just trying to “create” a backup for my own use of my music I already own.

Thanks again! Jim

Hi Jim,

I do note that you can still get vinyl copies in the US at a reasonable price-point - so if you know someone with the wherewithal to run a vinyl conversion for you (I’m in the UK - too far away for you realistically)

I used Audacity (and Brian Davies’ ClickRepair) to digitize my (and my wife’s) vinyl - producing some excellent results when played on our hi-fi rig.


When you do retension, if the deck does not have automatic braking I would recommend slowing/stopping the tape just before the end - to avoid a hard bump that may detach the tape.
(Professional studios rewind archive tapes at least once a year to avoid print-through)

And so make sure that the capstan and pinch roller are as clean as you can get them.

The other problem with old tapes is oxide-shedding when the magnetic layer can crumble off the backing material.

The 60s and 90s tended to be OK - certainly the TDK-Super Avilyn (that my Nak was designed and set up for).

The 120s were always much thinner and thus more fragile.