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Hi guys,

Someone out there must have an answer for me....

I have been trying to figure a way to record digitally at half-speed.
More specifically, I want to do sort of what Les Paul used to do. He'd record a basic rhythm track with a tape recorder (in the days of tape) at 30 ips, with normal instruments, THEN he'd turn the tape speed down to 15 ips and play a guitar solo VERY SLOWLY. Then, he'd put the speed back up to the higher speed, and hear the guitar playing blazingly fast. Because 15 ips was mathematically EXACTLY half as slow as 30 ips, the song would end up sounding in the same key. It could be done with tape, but there must be a way, digitally....
I don't want to use MIDI.
So, to recap: I want to record an acoustic instrument slowly, and then somehow turn the speed back of to the original speed of the original basic track, and hear the new acoustic overdub at double-speed, (but in the same key.)

I'll be your Number One fan, if you can clue me in on how YOU pulled this off, digitally.
(No theories on how you think it MIGHT be done....)

Oh, I'm using DP 9.01.

Thanks!

Dana Countryman
www.danacountryman.com

happymoogman wrote: I'll be your Number One fan, if you can clue me in on how YOU pulled this off, digitally.
(No theories on how you think it MIGHT be done....)

I was going to think on this problem and perhaps make a suggestion, but then saw that you only want people to respond who have actually done this, so I’ll hold off and wait for someone who has done this to chime in.

Some DAWs provide Varispeed recording and playback. Haven't heard of DP allowing such operation.

That said, any sampler can do what you wish to do; record your guide track, sample, then play it back an octave lower, perform your part (slowly and lowly) and record in the sampler then play it back an octave higher along with the rest of the production running at original pitch/speed.

I like Varispeed, not so much for half or double time work, but for subtle timbral shifts. Like 1/4 - 1/2 step.

With most Audio Hardware, within DP you can change the recording sample rate. The relevant pairs are 44.1K / 88.2K, or 48K / 96K.

The other step of the process is that you open the Soundbites window, and select the tracks you have recorded. Now from the Mini-Menu, choose "Convert Audio File..." There's an option-box that says, "Only change the file's recognized sample rate but do not process the file's audio." Check that. Between those two steps, you get everything you need.

Logic's Varispeed is probably closer to what you want, but I've done guitar solos at half speed then used DP's stretch function to reduce the length of the soundbite to half it's original length. That method does not require any change in pitch -- it just plays the audio faster. This sound is maybe not what you want. It has different artifacts from those you get with real varispeed, but it's easy to do so worth a try.

....and Harrison MIXBUS too!

ZTX will do exactly what you want—change pitch, speed or both. It's in the User Manual, not the Plug-ins Guide. Start at pg 921
https://cdn-data.motu.com/manuals/softw ... +Guide.pdf

I've never tried to change pitch and speed simultaneously, however, because it's really easy to do that in a single window using the ZTX tool in TwistedWave.

To just change the pitch of an entire track in DP but not the speed, I like Melodyne Essentials. You can do the whole Alvin & Chipmunks without singing half speed first like Ross Bagdasarian (David Seville) did. On complex tracks—anything other than single note or voice—Melodyne Essentials can only change the track or selection (unlike Studio or Editor where you can grab individual notes) making it perfect for many uses.

Thanks to everyone who posted their ideas about how to record audio files at half-speed.

Changing the sample rate didn't work for me, because dropping it down doesn't reduce the original by EXACTLY half.
I ended up using Audacity, in addition to DP. It's a free, cross-platform audio software. I made an audio mix of the original backing "track", and reduced the speed and tempo by exactly half, using the "change speed and tempo" setting in Audacity.
I changed the "Speed mulitiplier" to "0", and the "percentage change" to -50.000

That converts the track mathematically to twice as slow and one octave lower, exactly, in the lower key.
Then, the half-speed file is opened in a new DP document, to have new parts added in real-time, or with MIDI.

When the new audio parts are satisfactory, it is time to speed the tempo and pitch of the "slow" files in another Audacity file, to match the main tracks' original speed and tempo. There, they are dropped into the master DP file, in perfect synch, tempo and pitch.

it's actually a bit of work to pull all this off, whereas on an old tape machine, the same effect was quickly done with a simple twist of the speed switch. For recording acoustic instruments (pianos, guitars, etc), this digital manipulation is effective, but what I learned about recording synthesizers this way, is that speeding up a synth isn't really that noticeable to the human ear. Synths have a strange enough sound already, so they don't sound ALL that much more radical recorded at half-speed and then sped-up. Recording a synth with MIDI at a slower speed, and then just playing and recording at the original MIDI tempo works just as well.

Anyway, it was an interesting experiment, so thanks for the input!

Dana Countryman

happymoogman wrote: ↑Sun Feb 04, 2024 9:17 pm Changing the sample rate didn't work for me, because dropping it down doesn't reduce the original by EXACTLY half.

It's worked for me in the past. Did you change between 44100 and 88200? Or 48000 and 96000? If you criss-cross beween the 44.1K world and the 48K world, it won't be exactly half. Otherwise it should be, unless there was some other auto convert that was coming in and messing things up. I think I have the auto convert turned off.

But Audacity works well for this kind of thing-- but it's a few extra steps getting out and back in to DP.

Again, ZTX will do exactly what you want in DP.

mikehalloran wrote: ↑Sun Feb 04, 2024 9:49 pm Again, ZTX will do exactly what you want in DP.

That makes sense. At first, I was thinking that ZTX would use sample drop/add (i.e., drop samples to pitch up, and add interpolated samples to pitch down); but I think no matter which workflow, that is going to be necessary.

I've tried using the ZTX in a varispeed fashion, but, only seem to get either a time stretch or a pitch stretch. I'm not trying to do a half-speed conversion thing though (I have done various half speed things using Spectral Effects - it usually creates a lot of sound artifacts though) and it looks like there are ways to do a half speed result using 88.2 to 44.1, or, 96 to 48 conversations.

I'm trying to something a little more subtle by only reducing speed by about 5%. It looks like Pitch and Stretch should be able to "varispeed" down in variable increments, but, I can't seem to find a way to get pitch AND speed at the same time. I've tried a lot of different things and read every page of the manual, but, can't seem to get the simultaneous thing to work.

Can anyone list steps to achieve this?

Thank you for your help if you can.

Could it be that maybe DP just isn't really optimized or up to this? Maybe it's best to export to some sort of external editor and then import back into DP. Just saying. it would be nice to do it inside DP, but after trying to pound nails with a screwdriver for a while, might just give up and reach for a hammer? I dunno.

James Steele wrote: ↑Mon Apr 01, 2024 11:15 pm Could it be that maybe DP just isn't really optimized or up to this? Maybe it's best to export to some sort of external editor and then import back into DP. Just saying. it would be nice to do it inside DP, but after trying to pound nails with a screwdriver for a while, might just give up and reach for a hammer? I dunno.

Well, the work flow I described above isn't so painful. And as MH said, ZTX does it as well.

I’m in the middle of a recording project where I have to match the phrasing of a … I’ll say ‘quirky’ lead singer. Singing against a half-speed playback is a big help for everyone. Manipulating the sample rate is quick, easy and perfect.

This same project came to me with acoustic guitars and mandolins recorded elsewhere with instruments tuned to an uncalibrated tuner — no one noticed till the bass was added. I could have used ZTX but went with Melodyne instead since I could tune the track in real time instead of calculating the difference. The basic version found in DP works great for this.

Changing pitch and time using ZTX is doable in DP (pg 921 in the User Guide) but to do both in a single operation is much easier in TwistedWave where you can calculate both in a single window.(It would be great if DP gave us a similar editing window). I have a screen shot of that window in this thread from last year:
https://motunation.com/forum/viewtopic.php?p=601124

TwistedWave can use either Apple’s pitch shift (the one used by Logic) or ZTX —your choice.
https://twistedwave.com/doc/index

TW is now available for Windows, too.

Real time Varispeed where you turn the knob and both change over time as in analog machines? I’m told that is best done in Logic or Audacity though I’ve never tried it. There are other apps that claim to do it better. No one has ever asked me for this.

Falcon uses IRCAM’s TS to change time and length but I’ve never used it other than as an effect—too many artifacts for me, same as the stand alone IRCAM TS2.