Tape Wobble

[mikeebb]

Crazy thought - could you analyze the sound file to figure out the low-frequency signal of the wow or mid-frequency flutter, then apply an equal and opposite frequency in the speed-change filter? Assuming of course that it's regular (as with a record with an off-center hole) - I've had tapes that vary along the length of the tape if the tension is low and a flange is dragging hard.

[Craig Maier]

Hi Mikeeb,

How do you discriminate between the natural FMing that one gets with music and human voice and distinguish it from the FM of wow and flutter? As an intuitive example, imagine an opera singer and imagine the amount of Vibrato contained in her voice. Now, imagine this theoretical system that we are talking about removing not only the wow and flutter, but her Vibrato. I think that would generally be considered to be quite musically unacceptable. And, if the system did lock onto her Vibrato and eliminated it, it would still leave behind some vestige of the wow and flutter affiliated with other musical instruments which would sound like artifacts.

Craig

[Craig Maier]

General Notice:

I just received a telephone call from Mr. Howarth from a friends house (Gregory Creedon) on Nantucket island. This call came in on my wife and my personal (non-business) line at 7:56 PM. Mr Howarth spent 15 seconds cursing me out (with 4 letter words) for my postings here pertaining to his so called technology. I do not tolerate that type of telephone call and thus hung up on him. Here are my suggestions to Mr. Howarth:

1. Since you claim to have this technology, Mr Howarth, provide a system that performs the task and sell it to those who need it. You will make a lot of money doing that. You will not capitalize on it by talking about it or by cursing out myself or others for expressions of skepticism about it.

2. If you do not have the resources to commercialize this technology yourself, consider licensing it to one of our competitors. That would be the best way to "stick it to Diamond Cut" - - - wouldn't you agree? That approach would surely beat cursing me out on the telephone for my views on this subject.

3. In the meantime, do not telephone me again with a string of curses as you did tonight. For that matter, never call me on my personal telephone line. I will view that as harassment should it ever occur again. Remember, I have Gregory Creedons tel number (caller ID) - - - the one from which you called me tonight.

Sincerely,

Craig / Diamond Cut Productions, Inc.

[cromag]

I hope you filed (or will file) a report with your local police department. I've been out of the Bell System/AT&T loop for some time, but it's important to document harassment. If you have not already done so, don't clear your Caller ID memory.

[Craig Maier]

Hi Cromag,

I have done both and the number is still in our caller ID memory.

Thanks,

Craig

[ckrate]

Seems to me it would be simple enough to phase-lock to 60Hz, which is how we did it in the analog days.

[Craig Maier]

Tape wow and flutter can have delta f/f components that extend out to 250 Hz. By Nyquist, locking onto a 60 Hz signal would only allow a maximum theoretical FM component up to 30 Hz to be removed by the PLL. In practice, it will be less than that. Thus, the 60 Hz technique would be very limited in utility. That is why we have not done that. Refer to the Diamond Cut Glossary in the users guide or helpfile under wow and flutter for the industry standard definition of the frequency content of those signals (0.5 Hz to 250 Hz). Basically, you can not get there from here, so to speak.