Help With Noise Removal In Classical Piano Piece

Are you sure that you used a “Line out” from the piano and not a “headphone out”? (headphone outputs are often more noisy than line-out sockets).

Again this makes me think that you may be using a headphone output on the piano, or a microphone input on the computer.
Connecting a Line out to a Line in should give a good level with both output and input level controls set to around 75%

If you are using the only sockets available, try turning down the level on the computer and increasing the level on the piano.

Yes, I’m pretty sure. It’s the same port that I use for connecting the speakers to the piano (using RCA). So it’s two RCA ends (red and white), the small size (I think 1/8"?). To be precise, it’s this wire: . That IS correct, right? Those plug into “L/R”, and not “L+R/R”, but I don’t think that matters.

Let me know if I did something wrong. When I have time I’ll definitely try again, while having the piano louder and computer softer.

Thanks a lot!

<<<the output volume (on the piano) was very low, because anything higher distorted the piano sound>>>

Distorted it where? How were you listening when it started to sound funny?

Who made the USB device? Part numbers.

You have all the characteristics – including background noise, of reducing the signal greatly so you can pump it back up again in the next device. Each pump adds noise.

Taking sound directly from a keyboard or any electronic instrument should give almost perfect electrical characteristics, not a performance that sounds like you put a good microphone in the room with the artist.


This six second thing was recorded exactly the way you’re trying to. Very Large Yamaha Keyboard headphone out into a Mac PowerBook Line-In.

Macs do this without the USB Device step, but you should be able to do as well properly tricked out with appropriate hardware. What is your hardware?


Hey kozikowski, thanks a lot for your help.

I just had some time to try out another short recording session, and I’m surprised to see that I can record at a higher volume now than before. I’m baffled = I know it didn’t work last time because I spent half a day trying.

Here is the result of the new recordings (two in one file):

The first was recorded at 70% both input and output. You can hear that there are quite a few crackles. The second was recorded at 60% both input and output. Only one tiny crackle now. I do notice that usually the crackles occur when the blue lines go off the sound track (when it’s loud). Perhaps that has something to do with it.

Do you think I should just leave recording as it is and not try to remove any noise? I can’t seem to do it without distortions. Also, I’m not sure why my noise is louder than that 6 second sample you showed me.


That’s clipping and is to be avoided at all costs.

What make and model of USB interface are you using? What settings have you made on the USB device (if any) and in your computer sound control panel? What make and model of keyboard are you using?

– Bill

Ah, so that’s it. I’ll definitely make sure to avoid that. Thanks for the tip.

USB: (no settings on it)
Piano: Yamaha P-80 (

Apparently everything works well now. Maybe I’ll just lower input or output level by another 10% and no more clipping will occur. So that problem has been fixed.

Now, in terms of noise, should I leave it as it is, since it’s not too bad, or try to somehow remove noise without distortion?

Thanks a lot for the help.

Is there not a switch for changing from microphone level input (very small signal) and Line level input (massively bigger signal)?
If there is a switch, then you have almost certainly got it switched to microphone and it should be set to Line.

Yes, that’s the Griffin iMic. I suspected as much when he said he was using a 1/8" input - the iMic is the only one I know of that uses that.

And yes, it does have a mic/line switch. Make sure it’s in the “Line” position.

– Bill


Yeah, I’ve already made sure it was on “Line” and not “Mic”. If I do switch it to Mic, the distortion and levels are indescribably bad =)

Did my latest upload with the new levels not produce the desirable results? I thought the new recording was quite manageable, although the noise level is still a bit higher than that 6 second sample recording that you posted.


Yes, that’s much better. If you select just the silence at the start and crank up the volume you can hear not only hiss but a bit of whistle. The manual for that keyboard is dated 1999. I think we may be hearing 10-year-old technology at work. On the other hand we may be hearing limitations of the iMic.

When you plug headphones into the keyboard and crank up the volume what do you hear?

If you set the keyboard volume to zero and the input volume in Audacity to maximum and record silence, what do you get? Then try several recordings of silence with the keyboard volume at, say, 3, 5, 7 and 10.

Finally, what do you get if you record without the keyboard connected to the iMic?

If the noise is from the iMic then you want to have the keyboard volume at the highest level that will not overload the iMic.

If the noise from the keyboard is constant for all volume settings, same principle.

If the noise from the keyboard is affected by the keyboard volume (which seem unlikely given the info in this thread), then see if you can find an optimum combination of keyboard output volume and Audacity input volume.

– Bill

The Famous Griffin iMic!

Famous for being one of the worst audio interface devices ever. They use battery from the computer to run their internal services and they’re not particular about how they filter or smooth it before using. This is the device that will let you hear the hard drive inside your machine start and stop because you can hear it clicking and bubbling behind the sound show. The iMic never had Line-In and Mic-In. It had a not strong enough Mic-In which was noisy and a Line-In that easily overloaded and created distortion.

Past that it was fine.

Shall I stop now? I put mine in the garage and I talked to one of the musicians at work and found that he put his… in a box in the garage. Best place for it.

You can help a little bit. You can purchase a wall-powered USB hub and run the iMic through that. The power to run the iMic will then come from clean, filtered wall power instead of dirty, noisy computer power. That might be all that’s needed to clean up the noise. Do not use the hub for anything else. iMic in, and output connected to the computer.


Thank you very much for the responses!

kozikowski: I just looked and happened to find a wall-powered USB hub. Didn’t quite help with the noise problem. The noise changed a little bit, but still has the same loudness. Here’s a really short noise sample, which you can compare with the previous recordings:

billw58: Here is an analysis of what you asked for:

When I plug in headphones to the computer, I get a standard noise. When I plug them in to the piano, I get the exact same noise, so I guess that’s a standard noise.

When piano volume is 0, or any volume at all, the recorded noise is always the same–the same loud one we’ve been trying to solve the whole time.

And, unfortunately, I can’t record without the USB device = My laptop doesn’t have a Line In port. So, I guess that question is still left unanswered, whether it’s the piano or the iMic.


One more test. What noise is recorded when the iMic is connected to the computer but the piano is not connected to the iMic?

– Bill

That’s a vast improvement, though as you mention there is a little bit of “clipping” (overload on the loudest bits). It’s about what I would expect with the equipment that you are using.

The noise level from the keyboard should be roughly constant irrespective of the volume level up to about 90% volume (there may be an increase in noise in the last 10%) so the optimum output level for the keyboard will be with the volume set pretty high (probably around 80-90%, though some keyboards give the cleanest sound right up at full volume). Unfortunately high volume on the keyboard is overloading the iMic so you are having to use the keyboard at less than optimum. In addition there will be noise from the iMic - Bill’s last test is looking at this and should give a rough idea of the iMic “self noise” though pre-amps will usually produce more noise with nothing plugged in than they do with something plugged in. A higher quality USB sound card with input “gain” controls should give a cleaner recording.

It may be worth trying with piano turned up to 90% and the imic turned down very low. If the piano is overloading the iMic input then it may distort no matter how low you turn down the iMic, but it’s worth trying.

In which case your a candidate for one of the USB soundcards that we know play nicely with Audacity - see this sticky thread:

There are others available - but as Koz says the Griffin is one of the worst (I put it on my original shortlist - but rejected it after reading user reviews on t’interweb).


Media files weren’t allowed at all. You can now attach a WAV, OGG or MP3 up to 1 MB to a post.


Ah… that’s it. It’s the iMic = Same noise. Looks like another sound card would be necessary. It’s unfortunate that I can’t afford to get a better one. I guess I’ll just do my recording with what I have. It’s not perfect, but in my opinion, it’s close to perfect.

I appreciate all your help with all of this! Thanks a lot.

I use a Behringer UCA-202. It’s line level only (but that’s what you want) and the noise level with no input signal is around -90dB which is as good as you get with a 16bit sound card.
Current price is around £23 GBP / $25 US

The great thing about noise in audio data files is that it can be only observed as a issue if it surpasses the threshold of hearing. In the event the amount of noise in an audio documenting could be very minute that hardly nobody can understand, you don’t should fear about seeking to remove it; however, if you want to, you are able to.

Noise that surpasses the threshold of hearing might not be noticed like a difficulty if it truly is masked by a fabric that may be louder. As an example, you would possibly come across clicks, pops and hisses distracting in the recording of the classical piano piece; having said that, they may not make any difference inside documenting of your heavy metallic song.