Basic audio functionality on windows laptop

baysidebas wrote on 7/1/2009, 10:53 AM

I would like to use the built-in audio facilities in my laptop as a microphone preamp (running Vista Home Premium. One would think that this would be a no brainer, there's a microphone input and a headphone output. However, none of the installed software has a provision for outputting audio while the microphone is active. This I can understand, with no headphones plugged in there would be a danger of feedback via the built-in speakers. But no audio utility has provided for an override. I would think that there may be some third party software that would allow for this functionality, that's why I'm turning to the brain trust for help.

The reason for my need is that I have managed to configure the laptop to simultaneously record from 3 cameras, with on-screen video from all 3. I need to communicate directions to the crew. A Clear-Com or Portacom system, $1200 and up, is out of the question. One way communications would suffice and I can use a mixer as a mic preamp feeding a headphone distribution amplifier (to the camera people), but if I could cut down on unnecessary equipment, I'd be that much farther ahead. Using hardware that I already must have on location would be most efficient. Thus, a boom mic equipped headset for me, going into the laptop with the audio output from the laptop going to a headphone distribution amp and on to camera operator's headsets.

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bsuratt wrote on 7/5/2009, 9:08 AM

Baysidebas,

What are you using for software to display/capture 3 cameras? Is this a mixer/switcher as well?

3 port Firewire card?

I'm looking for a similar setup.

MPM wrote on 7/6/2009, 4:34 PM

"I give up. Trying to duplicate registry entries was a no go since there weren't any English looking entries in either the new LT or the old one. In the old one I was able to pinpoint the entries that controlled the mic pass thru, but those entries did not exist in the new one nor would I take a chance adding same due to the cryptic strings used."

It can get real interesting real fast, once you start experimenting, & your theory could be right -- it only enables *if* a certain key is there. I get that a lot with ATI drivers in XP with Avivo -- knock wood, for me Vista's a bit better & 7 looks almost OK. If there's any Macrovision or other DRM, it came from the lt maker, not Realtek far as I can tell, but then getting rid of the Macrovision once it's weeded its way in can sometimes be tough, so it may not matter.

At any rate, before I get involved in something that can cause serious problems, I make a disk image to a 2nd drive, & then running LiveXP from a bootable USB stick it only takes 15 - 20 minutes to put things back & walk away sheepishly. ;-) That's not saying you should or shouldn't try -- people's memories are highly selective, & I only remember the times it's worked -- until the times it doesn't.

baysidebas wrote on 7/6/2009, 6:02 PM

For acquisition I use Adobe OnLocation for one camera and ScenalyzerLive for the other two. I would have liked to use OL for all, but OL will not run multiple instances on the same PC. As far as I know there's no such limit with Scenalyzer. Using a 7200rpm SATA drive handles the three streams with no problems. I've also successfully captured a single camera to an external USB2 5400rpm drive using OnLocation.

All three cameras connect to the laptop via FireWire, and this is the tricky part. I started out with the aforementioned Toshiba Satellite, which didn't have FW. So I got a PCMCIA FW adaptor with three FW ports on it. So far so good, but only for two cameras. Other posters on the forum mentioned successful multiple camera operation by means of a FireWire hub. Only problem was, even with a hub, I could never get more than 2 cameras to transfer a signal into the laptop, so my dream then languished. Last year I upgraded my laptop to a newer Satellite, this time with built-in FW. Great for a single feed, but even using a 6 port hub the old 2 camera limit applied. 3 devices showed in the selector menu, but only any two could be operational at one time, the third would report a "can't connect" error.

Reaching for straws I next got a 2 port FW PCExpress card, giving me 3 FW connections at the laptop. And bingo! there was joy in Mudville that night. All 3 cameras operational for capture, even when two of them go through a hub into just a single FW port. Best I can figure out is that there's a 2 stream limit per port, regardless of hub capacity.

baysidebas wrote on 7/6/2009, 6:11 PM

HTH, that's exactly how it works on my older Satellite, with the 6.0.1.5322 driver. I've not been successful in installing that older driver in the newer laptop. I'm currently researching the registry options, that's not the type of thing to do without a specific plan.
I've looked for info on the Realtek chipset but failed in finding it in the system info. It's only identified as "Realtek High Definition Audio".