Subject:Laptop sound card input

Posted by: philsayer

Date:3/7/2003 6:57:39 AM

AAAGGHHH - have just bought a laptop (Dell Inspiron 5100) so I can work abroad, taking mike, small mixer and laptop with me.

The sound card seems to have only a mic input, rather than line input.

Am I likely to damage the sound card if I plug the output of my mixer into the mic input?

I can't plug the mic into the input, as it's phantom-powered from the mixer at 50v., and anyway I need the other facilities of the mixer, such as EQ, monitoring via h/phones, etc.

Any help gratefully received!

Subject:RE: Laptop sound card input

Reply by: Chienworks

Date:3/7/2003 7:13:23 AM

Make a quick stop at your local RadioShack and pick up an "attenuating adapter". It connects to the end of an RCA cable and plugs into a 1/8" mini-phone jack and drops the signal from line level to mic level. I can't find it on their website, but i know i saw a few on the shelf at the local 'Shack here recently. It's red and costs probably around $3. Great little piece of gear; i've got about 6 of them in my tackle box. If they don't have one of those, they do sell a 6 foot cable with 1/8" plug on one end and RCA plug on the other which can do the same job.

Subject:RE: Laptop sound card input

Reply by: philsayer

Date:3/7/2003 5:27:32 PM

Thank you for that, Chienworks - I'm in the UK, but we have similar shops here - good to know that such a device is available off the shelf.

I have found that by adjusting the record level to very low, and turning the mike channel down on my mixer, that I can get it within the right range as is. I'd prefer something to attenuate the signal though - do you reckon I'm in danger of damaging the sound card if I leave things as they are?

Normally, the mixer is at unity gain, and a "mid-way" record setting on the record level on my office PC is perfect - but that sound card has a line input, of course. Does turning down the mixer output (either main out or the mic channel) reduce the voltage going out, and therefore make the sound card unlikely to be damaged? (You can tell I'm no electronics guru, huh?)

And if I DO reduce the output gain from the mixer, will that have a noticeable effect on the quality of the sound? (Which needs to be, and when connected to my PC, is, very good.)

Black mark to Dell for installing a sound card with no line-in. Blacker mark to me for not checking before I ordered it!

Cheers,

Phil

PS - Is there any likelihood of being able to permanently alter the laptop's mic input by making some kind of adjustment on the card itself or somewhere in the s/ware or BIOS? I'll never need to use an ordinary mic with the laptop...

Subject:RE: Laptop sound card input

Reply by: rraud

Date:3/7/2003 6:44:35 PM

You won't damage anything be feeding line level to mic level in, you will just get distortion. Lowering the mixer level is not a good solution, get an attenuater. I don't beleive there's any way to change the internal level....
Have you checked you sound card settings? Double click speaker icon to access the record/playback parameters

Subject:RE: Laptop sound card input

Reply by: philsayer

Date:3/8/2003 7:14:17 AM

Okay - looks like an attenuator is the answer if I stick with the existing plan.

I'm considering another option - if you've time, I'd appreciate an opinion.

*goes into lateral thinking mode*

The only real reasons for putting the mixer into the "portable studio" set-up are:

1. The mixer supplies phantom power at 48v to the mic.

2. I can monitor into quality h/phones.

I believe the mic can be battery powered - Neumann sell a battery pack (probably v. expensive, but never mind) and as far as I can see it uses XLR connectors, but there's not much other detail on their site. However, it must, by definition, output the mic signal at a level that would suit my laptop's sound card.

I'd lose the ability to EQ the mic, but then I normally use "flat" settings on the mixer, anyway. Any EQ I might need could be done post-recording in SF.

Although the mixer is small - about the size of a laptop - it's quite heavy (Mackie 1202-VLZ-PRO) so it would be a benefit to not need it.

I don't really need to monitor while I record, but could do so via the h/phone out on the sound card.

Can you think of any reasons not to go down that road instead?

Thanks for help received so far, by the way - I appreciate your time and wisdom!

Phil

Subject:RE: Laptop sound card input

Reply by: Chienworks

Date:3/8/2003 7:27:12 AM

That option should work fine too. You can use the sound card both for monitoring and volume level. All you'll need is an XLR to 1/8" adapter. This probably isn't a common item though so you may have to go with an XLR to 1/4" adapter and then a 1/4" to 1/8" adapter. Not a huge issue, except that you'll then have a solid slug of heavy metal plugged into the mic input jack on the laptop which probably isn't a good idea. If you're at all handy with a soldering iron, I would suggest buying an XLR jack (female, 3 holes instead of 3 pins) and any shielded audio cable you can get your hands on that has at least a 1/8" plug on one end. Cut whatever is on the other end of this cable off, then solder the center conductor to pin 2 of the XLR jack, and the outer shield to both pins 1 and 3. This way you'll only have a small plug connected to the mic input jack on the laptop and a lengh of flexible cable before getting to the large XLR connector which connects to the battery pack.

For reference, in case your local shop only lists metric sizes, 1/4" = 6.3mm and 1/8" = 3.2mm.

Subject:RE: Laptop sound card input

Reply by: philsayer

Date:3/8/2003 7:51:14 AM

Very helpful, Chienworks, as ever - thank you.

I think I'll go down that route. Easy enough to have an adaptor lead made up. I'll try to find out what the available outputs are on the Neumann battery pack - with luck, there may be phono (RCA) outputs or jacks as well as XLR.

I also use a phantom-powered Sennheiser MKH 416 mic for certain recordings and I believe there's a battery-powered version of that available (battery is inside the body of the mic.) e-Bay, here I come.....

:o)

Thanks again,

Phil

Subject:RE: Laptop sound card input

Reply by: philsayer

Date:3/8/2003 12:03:38 PM

And another possible solution (which may be of value for anyone trying to do something similar!)

An external sound card - Creative Labs Extigy has all the inputs I'd ever need and plugs into the USB port on the laptop. (I use the internal near-equivalent Audigy Platinum 2 in my PC, and it's plenty good-enough quality.)

Apparently the earlier idea (battery power for the mic, plug mic directly into sound card) would be unsatisfactory for two reasons. Firstly, the sound card in the laptop is poor quality to start with, surrounded, as it is, by all sorts of unscreened RF-generating bits and pieces. Secondly (and I'm not sure if this is correct info or not) the mic needs a pre-amp, even to bring it up to mic-input level. By all accounts, it's just not possible to buy a high-quality internal sound card for a laptop - not enough room, and too many sources of RF.)

Even as it is, the laptop is producing just-about-acceptable files using it's own sound card with the line out from the mixer connected to mic-in on the laptop. (I checked the quality two ways - plugging my nearfield monitoring speakers into the laptop directly, and, more convincingly, by copying the test file across to my PC and playing it back through the same speakers - not wonderful quality, but acceptable for most uses.)

Unless someone posts dire warnings, I think I'll try the Extigy. I'm also looking at a very small Behringer mixer (UB 802) with phantom power facility - easier to carry around than the larger and heavier Mackie, XLR connections, Aux bus (which means I could also use it with my codec machine if ever the Mackie died.) (Around £67 - about US$100)

At first glance, it must look as if I'm answering my own question here, but I can assure you your comments have helped me arrive at a better solution! (At least, I think so... unless you feel otherwise!) Thanks again.

Subject:RE: Laptop sound card input

Reply by: DavidGtz

Date:3/30/2003 6:34:23 PM

Hi,

Check out www.usbpre.com

We use their digital interface with our laptops and have had good results.