Distortion problem on piano recording

[Jim Robbins]

Yes there is mains hum, but the main offender is a digital whine …

peaks marked with red dot are digital whine.png

If the source* of the problem cannot be found the peaks could be notched out ...

before-after digital harmonics notched out.wav

dashed line 'perforations' (I didn't bother to notch out the inaudible ~16KHz tone in the 'after)'.png

[* possibly due to the laptop computer's internal sound card generating/picking-up clock noise , curable with an external one]

Hey Trebor, even with the whine sound, how can we explain the fuzzy, perforated piano sound? It isn't clean and pure.

I've just ordered an audiophile -quality external USB headphone amp unit. [NuForce uDAC2-HP (USB DAC/Headphone Amp)] Since it's only a headphone amp unit, I don't know how I could use it in this application, as the connection from my mixer to the laptop is a USB plug, not a headphone pin.

[Jim Robbins]

Yes there is mains hum, but the main offender is a digital whine …

peaks marked with red dot are digital whine.png

If the source* of the problem cannot be found the peaks could be notched out ...

before-after digital harmonics notched out.wav

dashed line 'perforations' (I didn't bother to notch out the inaudible ~16KHz tone in the 'after)'.png

[* possibly due to the laptop computer's internal sound card generating/picking-up clock noise , curable with an external one]

Once I download the notch filter plug-in, how do I get it to show up in Audacity's effects page? Thanks again. ...Never mind, just figured it out -- copied it to 'Audacity's plug in folder.

[Jim Robbins]

I got a second to listen to the last test.


You can hear the buzz at the mixer headphone connection, right? You don't need to have Audacity running? Disconnect the computer with everything else running.

Koz

I don't hear any noise with the headphones plugged in, not running Audacity. I don't even hear it with Audacity running. I DO hear it when I press "Record" in Audacity. I hear that single tone/noise. Would that also cause the piano itself to sound fuzzy and un-clean when recorded?

I've cleaned off all the plug endings with glass cleaner.

[Trebor]

Hey Trebor, even with the whine sound, how can we explain the fuzzy, perforated piano sound? It isn't clean and pure..

The thing which is causing the whiney interference could also be modulating the recorded sound making it fuzzy,
I've tried to replicate the distortion with a ring-modulator effect ...

Bgravato's acoustic guitar, before-after slight ring-modulation with square waves at 1,2,3,4KHz,, then distorted piano bit.mp3

(331.88 KiB) Downloaded 101 times

IMO its a sound card problem, not exogenous interference from lighting.

You could …
Try another sound recorder, e.g. windows sound recorder, to check the problem isn’t Audacity specific.
Check you are only recording from the sound-card line-in: I.e. all other recording devices are disabled.
Check the soundcard (and other) driver software for your laptop is up to date.

If the problem still persists consider buying an external soundcard designed for recording music,
rather the internal laptop one primaraily designed to capture SKYPE-quality voice recording.

[Jim Robbins]

Hey Trebor, even with the whine sound, how can we explain the fuzzy, perforated piano sound? It isn't clean and pure..

The thing which is causing the whiney interference could also be modulating the recorded sound making it fuzzy,
I've tried to replicate the distortion with a ring-modulator effect ...


If the problem still persists consider buying an external soundcard designed for recording music,
rather the internal laptop one primaraily designed to capture SKYPE-quality voice recording.

Hey Trebor,

I haven't had a chance to test the soundcard, but if I need to get an external one, how would I plug the USB cord from the mixer into the external soundcard, before going into the laptop -- since most external sound cards allow for a mini headphone jack plug. I've never seen a sound card that allows you to plug a USB cord into it before going into the laptop. Do you know of one, or is there a USB to mini headphone jack converter? Thanks for the help.

[Trebor]

... how would I plug the USB cord from the mixer into the external soundcard, before going into the laptop -- since most external sound cards allow for a mini headphone jack plug. I've never seen a sound card that allows you to plug a USB cord into it before going into the laptop. Do you know of one, or is there a USB to mini headphone jack converter? Thanks for the help.

Sorry i though you had an analog output from your mixer and were using the line-in on your laptop's soundcard.

If you're connecting via USB then your computer's built-in sound card is not an issue: it's not involved in the capture via USB.

You could still make sure no other recording devices, (e.g. your computer's line-in, if it has one), are being recorded with the USB, i.e. all other recording devices are disabled, as they could cause interference, and try other audio recording software to see if the problem is specific to Audacity.

BTW standard issue Audacity is not compatible with ASIO drivers ...

Standard audacity is not compatible with ASIO dirvers, try the standard windows audio drivers.png (20.78 KiB) Viewed 1928 times

http://www.alesis.com/multimix4usb

[Jim Robbins]

... how would I plug the USB cord from the mixer into the external soundcard, before going into the laptop -- since most external sound cards allow for a mini headphone jack plug. I've never seen a sound card that allows you to plug a USB cord into it before going into the laptop. Do you know of one, or is there a USB to mini headphone jack converter? Thanks for the help.

Sorry i though you had an analog output from your mixer and were using the line-in on your laptop's soundcard.

If you're connecting via USB then your computer's built-in sound card is not an issue: it's not involved in the capture via USB.

You could still make sure no other recording devices, (e.g. your computer's line-in, if it has one), are being recorded with the USB, i.e. all other recording devices are disabled, as they could cause interference, and try other audio recording software to see if the problem is specific to Audacity.

BTW standard issue Audacity is not compatible with ASIO drivers ...

Standard audacity is not compatible with ASIO dirvers, try the standard windows audio drivers.png

http://www.alesis.com/multimix4usb

Here's an image of the Alesis USB mixer I use: http://robbinswritings.squarespace.com/ ... mixer.jpg It didn't come with any software drivers to download, so I don't think the ASIO compatibility would be an issue, if I understand you correctly.

I'm a novice here: what's a "line-in" on my laptop? The online ports I see are mini-headphone jack, and USB ports.

Since the mixer connects to the laptop via USB, does that mean that it bypasses the laptop's soundcard altogether, and goes directly to and from the mixer into Audacity?

I also don't have any other recording devices connected to the laptop while I'm recording.

I'm still stumped as to where the whine and distortion are coming from if not from the battery or any other recording devices. This problem is a fairly new development, and I haven't changed my setup. Could it be a bad 1/4 inch cable [from the keyboard to the mixer]? One of the cables is at least 7 years old. The other one is gold-tipped and only 2 years old.
Thanks again for the help.

[Trebor]

I'm a novice here: what's a "line-in" on my laptop? The online ports I see are mini-headphone jack, and USB ports.

Your computer may not have a "line-in" socket..

I also don't have any other recording devices connected to the laptop while I'm recording.

When I said "recording devices" I meant the type of devices listed here ...

http://wiki.audacityteam.org/wiki/Mixer ... trol_Panel

which can include the computer’s built-in microphone, (if it has one),
"line-in", (if it has one), and the ability to record what’s coming out of the speakers aka "what-u-hear" aka "wav out". aka "stereo-mix".
You should only enable those devices you want to record from, in your case that’s only the USB device , as the unused recording devices could contribute noise to the audio capture and should be disabled..