Redbook CD pitch-shifted... why / how?

[sxuser]

Greetings fellow forum users! This is my first post. I recently acquired a used Tascam SX-1 and have been teaching myself how to use it. I've figured out, with the aid of the documentation and by experimentation, how to do the basics. I can record tracks; apply built-in effects to those tracks; mix them; and most recently, create a Redbook audio CD to listen to on my stereo.

Having successfully created a Redbook CD (with only a single track on it, as an experiment to see if I'd done it correctly) I listened to it on my stereo and to my amazement, the track appears to have been pitch-shifted. The song is in G, but played back, it's in F. I don't believe (although I haven't verified this yet) that the tempo has changed, just the pitch.

When I was playing with effects recently, on the very mix that I burned to disc, I played with several effects but pitch-shift wasn't one of them. I don't even recall seeing that effect in the list, although searching the reference manual there is a mention of it.

I'm sure I didn't play with any pitch-related features anywhere, and I have verified that neither the Conductor nor Metronome options are enabled. I have explored the interface fairly thoroughly and I'm at a loss as to how my CD got pitch-shifted.

Can anyone here point me in the right direction, offer a possible explanation, a theory, an idea...? I would much appreciate it. Thanks for reading.

Regards,
P.

 

[Phil Tipping]

Using a different sample rate causes pitch shifts. CDs use 44.1KHz so if you recorded at 48KHz and and it didn't convert properly it might explain it. Could check the maths to see if it explains a whole tone shift maybe?

 

[sxuser]

Phil,

Thank you very, very much. That was in fact the issue. Before reading your reply I created a new project, recorded a new take, mixed it, and burned it to disc, and it does not have this problem. Having read your reply, I checked the sample rate on this new project, it is 44.1kHz. I checked it in the other project, and it is 48kHz. I'm not sure how that happened, but I'm very glad to have an explanation.

Thanks again!
Peter

Edit: I did the math, and apparently the playback key is between F and F# (and very slightly closer to F#). Which perhaps shows that my ear "prefers" to hear something slightly flat vs. slightly sharp, because I played along with the CD on guitar at both F# and F and the latter sounded "better".

Math:

"recording sample rate" x "playback note" / "recorded note" = "playback sample rate"
That is,
48000 x 360.15 / 392 = 44100

392Hz is G4, and 360.15Hz is in between F4 (349.23Hz) and F#4 (369.99Hz)

 

[Phil Tipping]

Glad you got it sorted Peter, and well done for doing the math - I wasn't 100% sure if it would explain your symptoms, but you've now confirmed it I suppose the question remains why didn't the SX-1 do the sample-rate conversion? Is it a function you have to invoke manually before burning the CD or does it mean you can't use 48KHz projects for this?

 

[sxuser]

That's a good question Phil (why the machine didn't do the conversion) -- I don't know the answer. Going forward though, I'll create all my projects at 44.1 so that it's not an issue.

BTW, I was able to use Audacity to convert the pitch-shifted recording to 44.1 and it now plays back at the correct pitch

 

[Dice]

There is a way to convert with the SX-1, but it takes forever. Most people simply record in 44.1.