NBPK402 Posted November 25, 2015 Share Posted November 25, 2015 (edited) A couple of nights ago i was listening to some music at "-10 to 0", and noticed on a few tracks by Yaz that there was a sound that was like an electric motor running in the background. The sound was very noticeable, and went away when the song was paused. This was when i was streaming from my NAS... I then decided to try the cd, and found the same noise. The noise is only heard during the quiet sections. Has anyone ever heard anything like this that would only be heard on certain tracks? The tracks were "Ode to Boy, "Mr. Blue", and "I Before E Except After C". I have tried other songs on other albums, the noise is not there. The only thing I can think of is that maybe the noise floor on these particular tracks is lower, and allows the noise to be revealed? It would be difficult to isolate by removing pieces of equipment as this is the path Media player (or Oppo 103) > Yamaha CX-A5100 > MiniDSP DDRC-88A > Xilica XP 4080 > Yamaha MX-5000, and i have no spare cables for rerouting. One thing that was very interesting was that if I switched the Yamaha to 11 channel stereo the noise went to all the channels, which tells me it couldn't be the Xilica or the DDRC-88A. By deduction it makes me think something is picking up stray interference, but what could it be? The room tune has not been changed since the new Yamaha AVP went into use (about 2 months ago). We never noticed the noise when the Yamaha was put into use, but then again we never listened to those songs at that level either. Any ideas as to what is causing this noise? Edited November 25, 2015 by ellisr63 Quote Link to comment Share on other sites More sharing options...
Chris A Posted November 25, 2015 Share Posted November 25, 2015 The YouTube video of "Ode to Boy" has audible levels of 50/100 Hz line noise, if that means anything to you. You have to turn it up to about 80-85 dB at the listening position to hear it clearly. You can use Audacity's notch filter to remove that from your tracks. Use a filter "Q" of 20 at those frequencies that you can hear and see in the Frequency Spectrum plot. Chris 1 Quote Link to comment Share on other sites More sharing options...
NBPK402 Posted November 25, 2015 Author Share Posted November 25, 2015 The YouTube video of "Ode to Boy" has audible levels of 50/100 Hz line noise, if that means anything to you. You have to turn it up to about 80-85 dB at the listening position to hear it clearly. You can use Audacity's notch filter to remove that from your tracks. Use a filter "Q" of 20 at those frequencies that you can hear and see in the Frequency Spectrum plot. Chris Thanks Chris! I will download the software and give it a try. Quote Link to comment Share on other sites More sharing options...
NBPK402 Posted November 25, 2015 Author Share Posted November 25, 2015 I tried the notch filter, and I think i might be choosing the wrong frequency or the problem is mechanical. One thing i have not tried is... plugging my Yamaha directly into the wall instead of using my Monster HTPS 7000 power conditioner. I am going to power it direct to the wall and see if it clears it up. The thinking is it might be a fault with the Monster conditioner. Does the "Ode to boy" song have a noticeably lower noise floor by chance than other songs? Quote Link to comment Share on other sites More sharing options...
Chris A Posted November 25, 2015 Share Posted November 25, 2015 I tried the notch filter, and I think i might be choosing the wrong frequency There's a drop down menu to the left-top corner of the plot area. Select that drop down, then select "Spectrogram log(f)" view. You should see a colored spectrogram plot, and then you can see the noise in the quiet areas that you heard the noise. If you then select across the quiet area of the track with the cursor, then select Analyze:Plot Spectrum from the top menu, then you should be able to place the cursor over the exact frequency(ies) that you can type into the notch filter to get right on top of the right frequency (often it's 49 Hz or 51 Hz, etc.) You can also vary the "Q" of the filter to make the filter wider in the frequency domain to take out all the offending noise. "Undo" is your friend here in terms of trial-and-error. I didn't listen to the other videos, so I don't know about their noise levels, unfortunately. Chris Quote Link to comment Share on other sites More sharing options...
NBPK402 Posted November 26, 2015 Author Share Posted November 26, 2015 I tried the notch filter, and I think i might be choosing the wrong frequency There's a drop down menu to the left-top corner of the plot area. Select that drop down, then select "Spectrogram log(f)" view. You should see a colored spectrogram plot, and then you can see the noise in the quiet areas that you heard the noise. If you then select across the quiet area of the track with the cursor, then select Analyze:Plot Spectrum from the top menu, then you should be able to place the cursor over the exact frequency(ies) that you can type into the notch filter to get right on top of the right frequency (often it's 49 Hz or 51 Hz, etc.) You can also vary the "Q" of the filter to make the filter wider in the frequency domain to take out all the offending noise. "Undo" is your friend here in terms of trial-and-error. I didn't listen to the other videos, so I don't know about their noise levels, unfortunately. Chris I will try it again later tonight. Quote Link to comment Share on other sites More sharing options...
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