Stereo from Mono

Maverick wrote on 8/10/2007, 8:00 PM
Hi all

I have been given an old VHS tape to convert to DVD where one audio track is so badly damaged it is unusable.

I thought about trying to convert the other track to simulate a stereo effect and did a search here.

I came acroos the following thread:
http://www.sonycreativesoftware.com/forums/ShowMessage.asp?ForumID=4&MessageID=447101

where it was mentioned that:
'If you want to make a sound effect stereo, pan to one side and echo to the other.'

I'm not too sure what is meant by this. Could someone clarify for me, please?

Thanks.

Comments

farss wrote on 8/10/2007, 8:40 PM
First off, it's way easier to screw things up than it is to make them better. In other words be damn careful, by all means have a go but keep going back to where you started. I've spent hours making audio 'better' only to realise I was making it worse compared to doing nothing.

Secondly, always, always, without fail, check what you've done in mono. Vegas has a mono mixdown button. Get to know it and use it. Not everyone will hear what you've done in stereo and it's all to easy to make what they're going to hear sound woeful.

What, if anything you can do to make it sound spatial depends on what you have to start with. I've had some success with close miced vocals and instruments using the multitapped delay from SF with the stereo pan preset. It can place the sound in a space with little risk of problems in a mono mix. However if your audio is already mixed and with natural reverb or echo I'd procede with great caution.

The other suggest that you mentioned might work. Our ears determine where sound is coming from both by the relative level in each ear and the delay (phase) between when the sound arrives at each ear. Delaying one channel compared to the other can shift where a sound seems to come from. However again this can produce a problem, mxing the same sound back via a delay (that's what'll be heard in mono) produce a comb filter i.e. dips in the response, in extreme cases flanging like sound. So check whatever your doing in mono.

Probably impossible to know what, if anything, to suggest doing without know what's on the tape. And by the way, are you certain one channel is fritzed? Try a different VCR, mostly from memory stereo on VHS was on a FM carrier thingy, most unusual to loose just one channel. You might be just getting the linear tracks and one of them can get damaged.

Bob.
richard-courtney wrote on 8/10/2007, 8:41 PM
Drag your mono source to the project.
You will see a Pan Slider, slide it all the way to the left.

Drag another copy to the project.
Adjust the Pan slider on this track all the way to the right.

Add a Simple Delay FX.
Adjust the delay time to a small number such as 0.024seconds.

Adjust the Delay Out volume slider down a bit say -6dB.

This should give you a starting point.

EDIT: I noticed there is a Pseudo-Stereo preset you can select
TheHappyFriar wrote on 8/10/2007, 10:40 PM
how do you know the original source was in stereo? Many older VHS's were mono signals put out both channels. If so, just tell the event to use the good track & it will do duel mono.
Maverick wrote on 8/11/2007, 2:28 AM
Thanks for the advice.

I know the original source was stereo as it was edited by myself 7 years ago. The tape has had a lot of use, especially over the last year, and the quality of the video had degraded, too.

This is just a hobby for me and I am no expert in audio. As this is only meant for a domestic situation where the poeple watching/listening don't have such keen ears I think my job will be slightly easier.

I'll let you know how I get on.
Maverick wrote on 8/12/2007, 6:26 AM
I've decided to just cut the offending right channel and have the left play through both and re-add the music. THis has made things a lot simpler.

because I've needed to edit out some parts of the video stream which were also badly corrupted in the tape the audio has been chopped up quite a bit - that's not a problem in itself.

But that audio required cleaning up using non-real-time effects which works great. I tested it on one section. I need edto do the same for the rest, maybe 20 or so. Copying the audio event then selecting Past event attributes didn't work as expected so I have selected each audio event in turn after saving the first as a preset and contiuing that way. Is there a quicker method I have missed?

Cheers
farss wrote on 8/12/2007, 6:55 AM
Put all the events on the one track and apply the FXs to the track?

Hang on there's no event audio FXs anyway, what have I missed?

Ah, non realtime FXs!

Assuming they all need the exact same processing, put them onto one track, render to new file and process that file and drop it back onto the T/L?

Bob.
Maverick wrote on 8/12/2007, 7:01 AM
Thanks Bob.

Will work a treat, I expect :D

Cheers
TorS wrote on 8/12/2007, 10:31 AM
I believe VHS has the audio track on the edge of the tape, which is why one channel goes bad before everything else.
My suggestions are
1. try to play it from a better player - maybe there is more signal there to be had after all.
2. keep it mono. Few people will prefer bad stereo to half-good mono.
Tor
Maverick wrote on 8/12/2007, 12:58 PM
I thought that the Nicam Stereo sountrack was encoded with the video and that another stereo soundtrack was recorded at the edge of the tape. Is that still the case?

As I am just a hobbyist I don't actually have a video player so am limited to using my parents'. Theirs is a pretty decent Sony.

The two track monoral I have now used sounds reasonable considering how awful the original had become.
TheHappyFriar wrote on 8/12/2007, 3:07 PM
TV station new by? They may have a editing VHS deck with a TBC built in. could make a different in quality!