Raising audio level of vid files via 2nd sound card

[Fred Forsythe]

I have a remote TV on which we view a lot of dl'd videos, playing them on Nero Home. These are typically either .AVI's or DVD files (.VOB's). Fairly often, these files will have audio levels which are quite low; even with Nero & the TV's audio levels at full blast, some straining is required to hear quieter passages (recently had to view one film with computer speakers plugged into the TV headphone jack & turned all the way up as well, audible, but quite a lot of HISS!). I understand these files can be "remuxed" to raise the audio, but a more direct approach it seems would be to add more amplification. I have 2 sound cards installed (driver problems with the Soundmax card on my new build required me to run an old SoundBlaster card for awhile). I have tried running the output of the main soundcard into the mic input of the 2nd card, then taking the output from this second card, essentially adding another stage of adjustable amplification, however, there does not seem to be a way to enable BOTH soundcard outputs. In control panel, you can select one card for mic & one for playback, but BOTH CARDS would need to have playback enabled to accomplish what I'm attempting here. Not sure this would work in any event, but it sure won't w/o both card's playback enabled. Anyone know if it is possible to have both enabled for playback?

TIA

Fred

[johnny_quest]

Whoever was making the video didn't use enough gain on sound capture (the mic wasn't "hot" enough, no headroom). this will result in the quiet video, and when you try to increase volume, you'll raise the noisefloor proportionately (the inaudible noise will become much more apparent)

two sound cards will only make the problem worse, you'll be doing pretty much the same thing mentioned above, and you'll likely get a nasty feedback loop

some higher end sound cards will have zero latency plugins for things like gain/normalization. otherwise, you could probably use software but it might not sync up well with the video playback, due to the latency... but you never know.

or you could simple build/buy yourself a simple preamp box with a little potentiometer. your soundcard has one built in of course but it aint workin well enough...

http://www.till.com/articles/GuitarPreamp/
here's something you can build for 5 bucks if you're handy, should work for regular audio as well...

[mjc]

Personally, I would go the remaster route...break it down to audio/video fix the audio and then put it back together again.

[Fred Forsythe]

The schematic takes me back. Easy FET circuit, have to build 2 of course. Probably could run it with a suitable wall wart. Worth considering, thanks. Used to build & modify all kinds of electronic stuff, especially audio, back in my "Popular Electronics/Audio Amateur" days. Even build a vacuum tube preamp for my stereo about a decade ago, an updated version of the venerable Dynaco PAS 3. I guess I'm getting lazy in my old age, was hoping for a plug & play solution! :D

BTW the soundcard is actually onboard, mobo is Asus P5B Deluxe WIFI w/8 channel hi-def (so they call it) sound. I'll have to poke around & see if there's a software solution too.

Thanks for the reply!

Fred

[Fred Forsythe]

Personally, I would go the remaster route...break it down to audio/video fix the audio and then put it back together again.

Thanks for the reply. Probably should do that, if nothing else for the learning experience. I have an old copy of Cool Edit Pro which I gather can be used for this. In the mean time, I did find a "quick & dirty" work-around. My desktop pc speakers have an auxiliary input & a headphone jack. Placing this downstream of the soundcard output provides a suitable level of variable amplification, with surprisingly low additional noise. The low audio only effects maybe a quarter of the files I come across, so this should work at least in the short-term.

Dan