Normally I would ask this on tapeop but they're down so hope you guys don't mind.

I just started working in a digitization lab for a nonprofit making crappy old tapes sound like not as crappy .rm files for streaming from our webpages. My first project is to do some kind of magic with the audio from vhs tapes of an 80's detroit public tv show. The signal is low and comes in and out, and has lost most of its clarity. To work with I have 96-24 a/d's going firewire into a dell equipped with soundforge. Besides noise gating and compression, does anyone know of any other tricks that might help?

With sweepable digital EQ plugins you can find certain frequencies that are noise (ie. hiss) and pinpoint them and then remove them by pulling the gain down. I have seen this used in mastering of old tapes.

there's a plug-in called the Loudness Maximizer, made by Steinberg (i think it's Steinberg anyways.) it's basically a compression effect. easy to use and sounds good, i think. basically you move a slider up or down controlling how much gain you'd *like*. it'll get you a lot of gain and has some kinda peak limiting control going on (automatically) so your signal won't be allowed to hit 0. i especially like it on bass and drums, and entire mixes, but it may work for what you're doing here. i use it with adobe audition, but used to use it all the time when i used soundforge 4.5 a few years back.

good luck!

Yeah, that sounds like the 'L1' plugin in Protools. It is a really handy and super easy to use limiter. It has some silly 'voice over' type presets but can be used nicely to safegard or to squash.

I use the plug-ins waves r-vox (compressor for vocal) on the master and it is very good, it works on the sound is very light... sorry for my english...
If people want to limiter this processing signal wit a maximizer can use waves l2 with the treshold not over 2,5/3 db.

Thanks--

I'm going to look into that sweepable eq plugin. Right now I've just been doing real time spectrum analysis to find yucky frequencies.

As for compression, limiting... I kind of am having an overkill problem. I like the Wave Hammer (Volume Maximizer/Compressor) on sound forge 7, but I also have a Symetrix 628 digital voice processor, and a behringer multicom pro, both digital compressors, and i'm not really sure of the quality of either. (Furthermore when I requested manuals for my equipment I was told they had all been thrown away...good idea.)
I'm not really sure if I should just ignore the two rackmount compressors and do everything after a/d conversion in soundforge, or use them but then I would have to recapture everything if I changed my mind... This place is kind of weird because they haven't had an "audio" person here for years, the closest being their sweetwater sales person.

Anyway, compression won't solve all my problems, I'll have to do some serious eq'ing. Again: rackmount parametric eq or soundforge eq? Of course I could milk the clock and just try everything...

I would have thought that using proper noise reduction might be more useful than just using eq alone. There are good modern noise reduction technologies available which can be very effective.

An enhancer might help you "restore" some of those high frequencies if they are missing and brighten up the sound.

I agree with using the suggested loudness maximising plugins. They are very powerful. The steinberg one is great, as is the waves one. You generally get at least 3dB of volume increase in volume with those plugins with little consequence. I think i've got away with 6dB increase before now - listen carefully though.

Watch out for over-compression your material if you use standard compression too. Your material I assume will already have been compressed - you would really only want the compressor to "act" during dropouts as if it were riding a fader.

Remember that the order that you process in is vital - for instance, compression before noise reduction might not be a good idea.

de-ess the noise and use an exciter (harmonizer) to replace some hi freq content!!!! use an expander to bump the levels on spoken parts!!!! above all, remember to have a BLAST!!!

Rodabod wrote:I would have thought that using proper noise reduction might be more useful than just using eq alone. There are good modern noise reduction technologies available which can be very effective.

...Watch out for over-compression your material

...Remember that the order that you process in is vital - for instance, compression before noise reduction might not be a good idea.

i agree completely with rodabod. this sounds like the precise plan i would try first... noise reduction of some sort, and then a dynamics processing that would increase the level of the quieter parts to where they ought to be, and essentially leave the loud parts alone.

i have to get on my other computer to look it up, but i know there's either a Noise Reduction built into Cool Edit, SoundForge, or a plug-in that i have somewhere, that's really advanced. you select a segment of your program that represents the noise signature, and then it actively filters the entire program to drop out that noise when it's the only thing present, and decrease its presence when there are other things happening on top of it. i need to look up exactly what it is, i've only messed with it a couple times as noise is rarely the problem with my recordings, i'm dealing more with bad EQ, phase cancellations, and dynamics issues...

i would definitely deal with the noise first. and then i might try the Loudness Maximizer, but there may be a better approach even than that. i don't recall if SoundForge has this, but i know Adobe Audition does, where you can *draw* a compressor. it's an X-Y plot, with incoming level on the X axis and outgoing level on the Y. flat, it's just a diagonal line from lower left to upper right (upper right is 0,0 and everything else is negative relative to that point). so for example if you drew a horizontal line at the -10dB level on the Y-axis, that would take absolutely anything that comes in, and make it -10dB, your meters would be completely motionless sitting there at -10dB no matter what was playing, be it loud, soft, tape hiss etc.

so what you could do with that (dynamics processing -> graphic compressor, i believe it's called in CoolEdit/Audition) is to analyze your program material and get a feel for what the levels look like, and then use a compression scheme that will smooth it out a little.

like, if the good program material all pretty much falls in the -15 to -5 range let's say, and the quiet parts are down more like -30 to -15 and in there, what you could do is make a graphic compressor that will take anything below -40 and cut it out completely, take the range from -30 to -8 or -10 and make it end up basically being a much more horizontal line than it is, bringing up the left side (the -40 side) quite a bit (say, to -15 or so) and leaving the point -8,-8 or -10,-10 exactly where it is.

so what you'd end up with is, from left to right on the X-axis (incoming level) from -infinity to -40, it would be cut completely, to -infinity on the Y-axis. at -40 on the X-axis, the output would be maybe -15 on the Y-axis, and then there'd be a nearly horizontal line to the point -10,10, and from there on up it would be flat, normal, a 45 degree diagonal line.

the -40 low cutoff point and -10 point are both just wild guesses. without having analyzed your actual program material, i have no idea what the real points will be. but you get the idea...

there's a low threshold that's maybe 10 dB lower than what you think your quietest useful program material might be (you can push it close to what you think your quietest level is, but going too far can make things sound more weird than they need to).

there's a section that represents your "quiet material", the stuff that needs to be made louder, which will go from your cutoff threshold up to whatever point you think is the crossover between "too quiet" and "alright", and again here i'd maybe push the actual point a little higher into the "alright" range, but NOT TOO HIGH. if you go too far, you're gonna make it sound weird. i'm guessing.

experiment even with a cutoff of anything below 40, and then drop in two points, one at -40, -20 and another at 0, -15. that'll give you a pretty tight output range, basically only a 5dB range... that will probably sound pretty unnatural. but somewhere in between that and the more conservative approach i outlined above, there will probably be a happy medium that sounds okay.

i would NOT try to make it sound like everything is all consistent and at the same level. i would try and make it so the parts that are too quiet are still quiet but not *too* quiet. i would not try to make it so the parts that are *too quiet* end up sounding the same as the stuff that's loud and clear. or rather, i would try it, but think it highly unlikely that it will happen without sounding unnatural, and potentially very annoying. i don't know how much Listener Fatigue is an issue for what you're doing, but tweaking stuff too much can result in something that sounds *really good*, but after a minute or a few minutes, you have become agitated and don't want to continue listening. kinda like what can happen with rock music being overproduced. eventually its true unnatural nature comes through.

do you have SoundForge 4.5, or a newer version? i can check my plug-ins when i'm on my other computer, and check the software too, to make sure it has this same functionality that i know Audition has. it's been a few years since i stopped using SoundForge because i thought CoolEdit Pro had it beat for 1 and 2-track editing.

out of curiosity, what's the nature of the program material? what kinda 80's detroit show? is it bad ass?

yeah, even as far back as SoundForge 4.5 (1988) they have a graphic dynamics processor. it's on the Effects menu, under Dynamics -> Graphic.

i don't see any kind of Hiss Reduction process anywhere in the version of SoundForge that i have, and from checking out Adobe Audition's noise reduction stuff, it's a pretty impressive list (Click/Pop Eliminator, Clipping Restoration, Hiss Reduction, Noise Reduction) that i never even really paid much attention to. the Click/Pop Eliminator woulda come in handy on a couple recordings i did a number of years ago, had they made it back then. i used to just do it manually, 5 or 10 samples at a time.

you can probably find some kind of Noise Reduction and/or Hiss Reduction plug-ins out there on the net. hell, you can find Adobe Audition out there if you're into that whole illegal file-sharing thing. i wish it wasn't so damn expensive, but it is. if you can get your non-profit to spring for it, that'd be pretty rad.

good luck with your VHS tapes! sounds like a fun project.