Improving mono audio track

[GaryAllegra]

I captured a Linda Ronstadt concert I had on betamax to AVI to put on DVD. The audio was mono and not great quality. I used a Y cable so the L & R track are the same. Is there any way to enhance the audio and maybe synthesize a stereo-like sound?
This was a great concert that was on HBO in 1980. I'll take it any way I can but it would be good if it could sound better.

[Tommyknocker]

Load the AVI into Gold Wave. Save the file as a wave DV-stereo or whatever audio format you wish to use depending on you final file format. Now load the AVI into TMPGEnc as inptut video, and the new audio file as input audio.

[theDruid]

To improve the quality at all, you'll need some good audio editing software.

There are quite a few in the tools section, ranging from freeware (Audacity), to pro (Soundforge), via a few in the middle (CoolEdit and GoldWave).

GoldWave is not expensive - and in fact I can't remember what the restrictions are in the trial version - but it's very good.

It has some filters etc.. for cleaning up audio captured from audio cassette, or vinyl etc.. These might be of some use to you.

Creating a stereo audio track from your mono source will be a whole world of pain! You can do some basic things like EQ'ing each channel a little differently, but anything more complex than that will take a lot of doing.

One idea is to use a sequencer (like CuBase or CakeWalk) and layer up different tracks which you've run through EQ and filters, so each different track is a copy of the mono source but with different frequencies boosted and cut. You could then try and mix this down and pan it to stereo - but it sounds like a lot of work to me, and I'm not even sure you'd be able to get it sounding half decent unless you really know what you're doing.

I would stick to just cleaning up the mono as best you can, unless you have a few months free and a limitless supply of patience!

cheers,
mcdruid.

[Tommyknocker]

Creating a stereo audio track from your mono source will be a whole world of pain!

Really? I just loaded the mono audio file and saved it as a stereo file. It sounded very good.

[theDruid]

ha ha ha - If you read what he said, he used a cable to copy the mono track to the L&R channels - so he's already got a stereo file in terms of having a Left and a Right (although he didn't need to do this with a cable, as you correctly point out).

I'm pretty sure what he was asking about is taking a mono source (albeit spread across two identical channels) and doing something to...

synthesize a stereo-like sound?

... which is what I was talking about - trying to spread the mono track across left and right so that they sound different and you get stereo separation etc..

[thing914]

Definitely check out the audio programs. I've been reading so much lately that I can't remember exactly which but might have been in the Adobe Audition (old Cool Edit ) manual that there was a feature to do like you want.

You already have it in both stereo tracks. This feature let you play with the spacial orientation by slightly delaying (milliseconds) the sound on one track. So if the camera was placed to the left of stage you could make the sound seem to be coming from the side to match. Now if there is a lot of shifting camerawork then you will have a lot of work to do if want to match it. But there are features in some of these programs to help with simulated stereo.

[SLK001]

Cool Edit can do this (as can others). Simplest way is to just add a delay of ~50mS to one track. More complex consists of delay, then mixing. For example:

New L = 75% Old L + 25% Old R delayed by X mS.
New R = 75% Old R delayed by X mS + 25% Old L.

Or something like that. The results can give you pretty decent pseudo-stereo performance.

[bode]

I wouldn't honestly try a pseudo stereo effect, just keep it double mono.

I think the delay method could sound awful and may cause a swirling sound. The main thing is too remove the hiss caused by your analogue Betamax tape. If you have access to Soundforge and the Noise Reduction filter , you should use that.

I tend to just use a 20 band EQ, to isolate the hiss and drop the appropriate frequency...10kHz or 7.2. Drop the other frequencies also and keep it in a gradual curve.

It sounds good and natural for my fussy ears

[GaryAllegra]

Thanks everyone!
I downloaded Audacity & played with the noise reduction filter. It distorts the sound slightly. I think my best option is to leave it alone. It is rock, therefore it gets played loud and the hiss is really minimal. As for the mono, I'm going to let my receiver do the stereo/5:1 simulating.
Thanks again!!