Problems recording sound on the computer

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  • #1
Borek
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Not sure where to post it, but perhaps EE will be OK.

I have problems recording sound on my computer, and I have these problems for as long as I remember - using several microphones and several computers in the last 20 years. I always thought reasonable quality mic and reasonable quality sound card should work together out of the box, but sound was always way too quiet and I had to boost the recording level to maximum at the price of increased noise. I understand it is possible there is some mismatch in the signal levels and impedance, but I thought there are some standards that should make my life easy - apparently I was wrong, or unlucky, or something.

Up to now it was never something important, but now I want to make some presentations and I want as good sound as possible.

Can you point me to any reasonable source of information about how to record the sound properly? I did some digging, but somehow most of the pages I visited either explain how to start Windows sound recorder and how to boost the recording level using control panel, which is not the path I want to follow - as it doesn't yield good results. As it was always this way for me I suppose I am making some systematic error, but I have no idea what to look for.

Mic I am trying to use is a Rode VideoMic with its own fresh 9V battery, connected to my computer mic input. Mic output impedance listed as 200 Ω, ALC887 input impedance listed as 40 kΩ (unless I am misreading something - there are separate line-in and mic-in inputs, but one number listed in the chipset specification, perhaps I am looking in a wrong place, http://www.hardwaresecrets.com/datasheets/ALC887.pdf p. 68).
 

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  • #3
Borek
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No, as of now I am trying to record things without buying anything new.

I paid something like $180 for the VideoMic, it is not some cheap trash - which is one of the reasons I am reluctant to buy another mic. I have another mic, which is a part of some Creative Labs headset, but it has exactly the same problem.
 
  • #4
AlephZero
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The data on page 68 looks like it refers to the "line" input, not the mic. I can't find anything in your PDF that gives the mic input specification.

Possibly, your problem is your mics are "too good". A computer that is not specifically designed for audio probably has a "mic" input designed for cheap, high output, high impedance mikes, not something with high quality.

The cheapest fixes would probably be either
1. Get a soundcard with an input that can handle good quality mic. Probably your Creative Labs headset was meant to work with a Creative sound card.

2. Get a mike pre-amplifier that will boost the mike input to "line" level.

You should be able to get either of these for about $50. A local music store (not a computer shop!) is a good place to get advice - then shop around the web when you know what you want.

http://www.directproaudio.com/shop/accessories/guide/microphone-sound-card.cfm
http://www.directproaudio.com/product.cfm?directid=42891 [Broken]
 
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  • #5
AlephZero
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If you bought the Rode to use with a camcorder of your DSLR, a "no cost" option might be to make the audio recording with the camcorder (with the lens cap on, so you get the minimum size compressed video!), and then use some free software on your PC to do what you want with the audio track.
 
  • #6
meBigGuy
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Looks like this chip has 4 0db inputs with a 10/20/30dB boost capability for analog microphones. So, you need to learn how to properly set the boost. If boosting causes quality issues it could be how the mic input is wired or routed to the chip. On board audio chips are notoriously noisy. One way to see if there is a digital noise problem is to do disk drive accesses while recording. It could be that you would get better recording with a $25 radio shack USB microphone than with a poorly implemented internal audio chip.

From the data sheet:
Wide range (–80dB ~ +42dB) volume control with 1.5dB resolution of analog to analog mixer gain
Software selectable boost gain (+10/+20/+30dB) for analog microphone input
All analog jacks are stereo input and output re-tasking for analog plug & play


Have you tried the Mic with skype? Skype has a test mode where you can record your voice and play it back. (just another data point - not sure it will be any different)
 
  • #7
Borek
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Thank you guys. Can't say I am happier, but at least I fell like I am better informed.

Probably your Creative Labs headset was meant to work with a Creative sound card.

Not impossible, although it looks pretty standard, with a green and pink plugs. It is HS-400, from what I understand it should work out of the box. I am not sure if the mike is powered or not though and I don't see any "power the mike" checkbox in my Windows setup. I do remember seeing such checkboxes in some other windows/drivers/hardware versions.

If you bought the Rode to use with a camcorder of your DSLR, a "no cost" option might be to make the audio recording with the camcorder (with the lens cap on, so you get the minimum size compressed video!), and then use some free software on your PC to do what you want with the audio track.

I considered this, and perhaps I will do it. However, while it will work for a presentations that I want to make once, I want to be also able to create this type of screencasts on the fly:


so any additional step is unwanted.

One way to see if there is a digital noise problem is to do disk drive accesses while recording.

Will check, but with 16GB RAM (so no swapping) and minimum to no disk activity during recording (judging by the HDD diode) I am most likely not listening to the disk, but to everything else.

It could be that you would get better recording with a $25 radio shack USB microphone than with a poorly implemented internal audio chip.

Could be, as explained earlier - I don't want to spend any more money on that unless I am sure it will work. So far I know it is not a problem to spend $200 and be still at point zero.

Have you tried the Mic with skype? Skype has a test mode where you can record your voice and play it back. (just another data point - not sure it will be any different)

Time to register at Skype, you say... And I was so happy not being registered for so long.
 
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  • #8
AlephZero
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Recording one audio track on a modern PC HDD will barely register in terms of disk activity. CD sound quality, 44100 samples/sec x 2 for stereo x 2 bytes per sample is less than 0.2 Mbytes/sec of data, compared with a maximum disk speed of maybe 30 Mb/sec. Recording 40 or 50 audio tracks simultaneously would be a bit more challenging, but probably not impossible even on a laptop.

A USB mike bypasses the whole problem, because the mike has its own A-D converter and sends .wav file data direct to the computer, bypassing the A-D chips in your sound card.

Like any condenser mike, your mike is powered - that's what the 9V battery is for! "Professional standard" mikes usually take so-called "phantom power" supplied from the recording device via the mike cable, typically at 48V and 1 to 10 mA current. But consumer devices like PCs and camcorders don't have the circuitry to provide that, hence the battery.

If you forgot to switch the mike on, I would expect you would get no output at all, not low amplitude.

FWIW I asked this question on a computer music forum I hang out on, but I didn't get any more information or ideas than what is in this thread already.
 
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  • #9
meBigGuy
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If you use boost, can you get normal sound level with no distortion (clipping)? You indicated there was a quality issue with boost. Was that noise, or distortion?

As for Skype, there is little chance it will be different than PC record mode, so it probably not worth registering.
 
  • #10
Borek
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Recording one audio track on a modern PC HDD will barely register in terms of disk activity. CD sound quality, 44100 samples/sec x 2 for stereo x 2 bytes per sample is less than 0.2 Mbytes/sec of data, compared with a maximum disk speed of maybe 30 Mb/sec. Recording 40 or 50 audio tracks simultaneously would be a bit more challenging, but probably not impossible even on a laptop.

That's exactly what I took into account, back in nineties recording was occasionally difficult because of the file size, today it is not.

A USB mike bypasses the whole problem, because the mike has its own A-D converter and sends .wav file data direct to the computer, bypassing the A-D chips in your sound card.

At the moment it starts to look like I have to choose between mike preamp and USB mike.

Like any condenser mike, your mike is powered - that's what the 9V battery is for!

Sorry for not being clear, I was referring to the headset mike.

FWIW I asked this question on a computer music forum I hang out on, but I didn't get any more information or ideas than what is in this thread already.

Thanks.

If you use boost, can you get normal sound level with no distortion (clipping)? You indicated there was a quality issue with boost. Was that noise, or distortion?

Noisy background. I can at least partially filter it out with Audacity, but as I stated earlier, I want to get rid of any additional steps to make my life easier in the future.
 
  • #12
I think you need to hunt for an Electret Microphone if you wish to us your pc card as a recording device.

I you can't buy one, get a cheap or deceased telephone answering machine that you can record your own message to wire up and test the quality side. http://en.wikipedia.org/wiki/Electret_microphone

There are many sources of these mic's.
 
  • #13
meBigGuy
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If it is noisy background and you can hear the computer operate (changing frequencies in the background noise) then there is no fix and you need to at least get a USB headset. Or better yet, get a usb soundcard like an M-Audio box. If you care about audio quality at all (including audio output) you need an external soundcard (ADC/DAC/whatever they call them). You can go really cheap too, like this one for $2.59 including shipping. https://www.amazon.com/dp/B003MN1LTQ/?tag=pfamazon01-20
 
  • #14
AlephZero
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Well, I would be a bit dubious about a product that cheap - especially since the tech specs only say "no drivers for Windows up to 2003 server", i.e. no mention at all of Vista, 7, or 8. Cynical me says it's a very cheap audio amp for speaker output, with a mike port of unknown quality thrown in for luck - but you already have one of those made be Realtek.
 
  • #15
meBigGuy
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USB audio devices that follow the USB Audio specifications require no driver. The device enumerates as a stereo output and mono input device, probably with volume controls. I design chips for USB audio devices and we have never written a driver. Works on Linux, all windows, mac, right out of the box. The real question would be choosing one with enough microphone gain.

Here is an example of a 1 chip USB soundcard. (not mine) http://www.qsl.net/om3cph/sb/CM108_DataSheet_v1.6.pdf

There are chinese knockoffs available for incredibly cheap, certainly under 50 cents in volume.
 
  • #16
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I would forget the mic input on the computer as one of the rings supplies power to what it expects to be a condenser mic.

You can go with the usb option or simply use a good mic and a mic preamp that feeds the line in.......if your computer is equipped and your software can be configured to use line in.
 

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