• Registered: 2010-01-22
  • Posts: 3

Topic: Using the DDS panel for real-time pitch shifting in Fireface

Has anyone used the DDS tab in the Fireface Settings control panel to pitch shift audio in real time? I'm trying to correct a stereo choral recording that drifts between one eighth and one quarter tone flat over the space of about 30 seconds.

  • marQs
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Re: Using the DDS panel for real-time pitch shifting in Fireface

Recently I've used DDS to pitch-align a song where an african ballaphone should be added but its notes where right inbetween the western scale. Worked perfectly for this case!

I think DDS is not intented for correcting pitch in the manner you describe. Audio slows down/speeds up with DDS, tape machine style and no care is taken of formants etc. Try Melodyne Editor maybe?

  • Registered: 2010-01-22
  • Posts: 3

Re: Using the DDS panel for real-time pitch shifting in Fireface

Thanks marQs. I think RME actually state in the manual that DDS can be used 'creatively' - which is what I'm trying to do. Melodyne is out of my budget range at the moment! As we're talking about tiny shifts in pitch and tempo this is not going to be noticeable and I can't hear any artifacts at all when I play back the audio and move the sliders up and down.

I'm guessing that you matched the pitch of your track to the pitch of the balaphone, recorded it and then reverted to 44.1kh on playback?
What I'm looking for is a workflow for outputting a 30 second clip of audio and then re-inputting to match the 'correct' pitch of the rest of the piece; specifically if there is any way of doing it internally and digitally (i.e. within my DAW software, Sonar). Perhaps RME could capitalise on the quality of the DDS sample rate conversion by producing a software plug in that interfaces between the Fireface and the DAW software.
Thanks

4 Reply by MC

  • MC
  • MC
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  • Registered: 2007-04-06
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Re: Using the DDS panel for real-time pitch shifting in Fireface

What you try to do is not possible without AD/DA conversion, as a changed playback sample rate will be recorded in sync with the same speed - so nothing changes!

Regards
Matthias Carstens
RME

MC's Website

  • Registered: 2010-01-22
  • Posts: 3

Re: Using the DDS panel for real-time pitch shifting in Fireface

Thanks Matthias,
What I was thinking I might do is make a digital copy to DAT (at 44.1) then record it back into Sonar using Fireface analogue inputs and changing the sample rate manually whilst I record. Any reason why that wouldn't work?
cheers

6 Reply by MC

  • MC
  • MC
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Re: Using the DDS panel for real-time pitch shifting in Fireface

Can't work as the speed shift is gone when you play back the data next time. You did not loose/add or change a single sample.

Regards
Matthias Carstens
RME

MC's Website

7 Reply by marQs (edited by marQs 2010-01-25 09:47:02)

  • marQs
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Re: Using the DDS panel for real-time pitch shifting in Fireface

I don't know Sonar, but I'm sure it has pitch functions that should be sufficient for the job as long as you don't care for formants or the needed changes keep small.

The way around - using the DAT - works when you either ...

- play back with DDS manipulations and record it to DAT via analog connections
or
- record it to DAT digitally and re-record it analogue into Sonar while DDS is active.

Keeping it in the digital domain would cause that also the DAT changes speed which makes no sense for what you want to achieve.

I'm guessing that you matched the pitch of your track to the pitch of the balaphone, recorded it and then reverted to 44.1kh on playback?

Yes!

Melodyne is out of my budget range at the moment!

Check out http://www.celemony.com/cms/index.php?id=demos - not sure, but I think, the demo versions run some days without restriction...

EDIT: demo version have restrictions...