hiss on microphone input when using USB soundcard

[jon_mendel]

When I use a USB soundcard with my laptop, I get a hiss from the microphone input on the USB device (clearly audible when I try to record or dictate). This takes place even with no microphone plugged into the input - it is therefore not a problem with the microphone. I have tried with three different sound cards (an m audio transit, and 2 vxi translators) and still experience the same problem. I have also tried the different USB ports on my laptop, and all suffered the same problem. I have tried dictating notes in different locations, in case it was just local interference, but the problem persists. My laptop is a VGN-A497XP.

Any suggestions re. a possible fix would be a great help, and I'd also be interested to know if anyone's had a similar problem. I use my laptop to dictate notes (voice recognition) and therefore do need to find a fix for this 😞

Jon

[Jay1]

is the noise there when u take out the usb soundcard from the laptop

[jon_mendel]

It's there when the soundcard is removed and there is a microphone (switched off, so no sound is being input) plugged into the mic socket to the side of the laptop, although it does sound like a slightly different pitched hiss... It was because the mic input was noisy and poor quality that I bought my external soundcard.

The only way I found to prevent the laptop from adding hiss to recordings is to mute the microphone socket (either on the soundcard, or the laptop's internal soundcard) - naturally, this also makes it impossible for me to dictate

[Jay1]

is the noise still there when there is no mic connected to the laptop- in other words the jack plug is disconnected from the laptop and the sound card as well. with mic enabled on the laptop software

[jon_mendel]

yeah, unfortunately so. The one other thing that stops it is unplugging the USB soundcard and turning off the 'microphone boost' option (under 'advanced', in windows volume contol). However, my microphone will not work correctly without this option enabled 😞

Thanks,

Jon

[jon_mendel]

hmm. I use the laptop to listen to music, and had found that, when the laptop was plugged in but turned off (connected to amp through headphone output) and the amp was up high there was a buzz through my speakers. I'd therefore thought there might be mains interference on the mic input so tried running the laptop just off the battery (mains unplugged). Exactly the same problem 😞

[Jay1]

well tht sound normal.

if the noise is not there with the boost turned off then why is it there with it on. what mic u using is it them powered ones with a battery. anysway i cannot really help u as i hav no usede tht boost thing and i would recommend contacting sony to find out it not the laptop but before u do tht find out tht is not the mic doing it. and also find out if another person with the same laptop does make tht noise when the boost thing is put on if the answer is no then it is the laptop.

[jon_mendel]

Thanks. Have contacted Sony's e-support and will see how I fare...

I should clarify: the external soundcard's I tried all have a permanent hiss (unless I mute the microphone); turning off the 'microphone boost' only helps when using the internal soundcard.

I'm using a radioshack 33-3012 microphone, which does come with battery box; however, it still needs the 'boost' as well. It's not the mike causing the hiss - this happens even when the mike is unplugged... I *could* perhaps try to rig something up with a preamp to use the internal soundcard without battery boost, but don't want to have to buy more hardware and tbh had bought the external soundcard because (even using a mike that doesn't need boosting) the sound quality when dictating through the internal soundcard was poor - made my voice sound kind-of robotic... In other words, I'm currently stuck with dictating through either a poor quality internal soundcard or a decent external one, but with hiss 😞

Thanks for the help anyway, fair enough it you don't know the answer.. . If anyone has got this model laptop (VGN-A497XP) I'd be interested to know if you have the same problem. Anyway, wish me luck with e-support...

Jon