Subject:Changing phase between channels?

Posted by: plasmavideo

Date:4/25/2007 6:24:42 AM

One of the new features in V9 is the phase scope for checking mono compatability between channels . This is very welcomed by me.

However, I would like to take advantage of this by being able to phase shift, or shift one channel in time, to accomplish better phase matching. An example would be a stereo file that was transferred from a misaligned tape deck to a computer file. I do a lot of that kind of restoration.

Unless I'm missing the obvious, I don't see a quick and easy way to do this in SF. Nero's Wave Editor which comes with Nero Ultra edition has a "Stereo Enhancer" function. Within that plugin there are several controls for widening or narrowing the stereo image. Also included is a slider for shifting the relative delay of the 2 channels for enhancing the effect. My method for using this function is to set the stereo widening effect to zero, summing the output of my external mixer and headphones to mono, and adjusting the delay between channels until the high frequency response appears to peak in the headphones. I've also used a borrowed external phase monitor for processing a critical file.

Now with the built in phase monitor, I would like to do it directly in SF, so I'm open to ideas. I guess I could select one channel and play with the Sony Simple Delay settings and see how that works, but I'm wondering if anyone has a better solution. On complex stereo waveforms it's going to be hard to check phase on the scope unless there is a portion of the recording that was recorded equally in both channels originally.

Also, is there a way in SF to sum both channels to mono only for monitoring, not by doing any type of channel mixing or resampling, to eliminate having to have an external mixer to do the summing?

EDIT: It looks like the Simple Delay adjustments are too coarse to be useful, so I'm still looking.

TIA

Tom

Subject:RE: Changing phase between channels?

Reply by: ForumAdmin

Date:4/25/2007 7:08:41 AM

To sum both channels to mono for monitoring, simply assign both channels to the same hardware output. You'll probably want to open the Hardware Meters and drop the monitoring gain down a bit, as this is a straight mix.

Process->Pan/Expand provides similar narrowing or widening functions, but does not include the intra-channel delay functionality.

Given the way that Sound Forge's selection and fx preview are tied together, you'd need a plug-in with channel independent delay settings to be able to adjust in real-time. It's certainly not difficult to do, just atypical. I wouldn't be surprised if there was a shareware/freeware plug-in floating around the web that did this.

Barring that, you could experiment with inserting different amounts of silence on a single channel. Not very interactive, but would get the job done.

With the obvious exception of not (yet) having phase meters, this is a snap in Vegas or ACID, where you can split the channels to separate tracks, route them to the same bus channel to mix, and slide them around during preview or add a mono delay to one track and adjust to suit. Might be worth your time to check one of them out if this is a common task for you.

J.

Subject:RE: Changing phase between channels?

Reply by: plasmavideo

Date:4/25/2007 2:58:11 PM

Thanks. The addition of brief silence to one channel or the other was how I used to do it in Cool Edit Pro a few years back.

I like the Vegas suggestion, I'll give that a try tonight.

Tom

Subject:RE: Changing phase between channels?

Reply by: rraud

Date:4/25/2007 5:12:06 PM

Tom,
A while back I downloaded a really good VST oscilloscope with lots of delay and other options + a mono audition button which I frequently use to check phase, ect. I'll look for the URL when I have a few minutes or I could e-mail you the DLL file.
Rick

Subject:RE: Changing phase between channels?

Reply by: owlsroost

Date:4/26/2007 3:47:44 AM

There's a couple of freeware VST delay plugins (with independant L/R settings) here:

http://www.voxengo.com/product/audiodelay/
http://www.voxengo.com/product/sampledelay/

...and this is handy for mono/image width modifications: http://www.voxengo.com/product/msed/ (run it in 'inline' mode and adjust the relative levels of mid and side - more side = wider image)

For L/R phase adjustments try 'PhaseBug' from http://www.betabugsaudio.com/plugs.php

Tony

Subject:RE: Changing phase between channels?

Reply by: rraud

Date:4/26/2007 2:17:54 PM

Update: The VST shareware "C-Plugs" C_Super stereo scope was developed by Nick Whitehurst . There was also a C_Tuner and C_FFT plug.
My search revealed info but dead links for download.
If anyone else finds or has info on this, I'd be interested if there were updates ect.

Subject:RE: Changing phase between channels?

Reply by: Geoff_Wood

Date:4/30/2007 12:06:18 AM

To side one or both channels of a stero track, try Analogx SampleSlide :

http://www.analogx.com/contents/download/audio/sslide.htm

Does it by time or samples. Freeware.

And check out the others, especially DXPAD. But SCSI-dudies, why do we need a plugin for such a useful (essential ?) and basic function ? Surely a dockable 'Notepad' window wouldn't be difficult , and something more focused and incredibly useful not much more difficult. V8 ..... ?

geoff