More > JRiver Media Center 25 for Mac
EQ Anomaly in DSP Studio
blgentry:
I hear this too.
As the OP said, you have to play it kind of loud to hear it. It also helps if you increase 60 Hz to more like +8dB. I can also hear the effect at +4, it's just easier at +8.
Strangely, you can really hear it if you pause and unpause the track several times. It's probably a matter of catching the leading edge of the waveform or something. Several times when I unpaused, I got a very distinct 60Hz "hum".
So, I can hear it. Does that mean it's a bug? Frankly I have no idea. Maybe an analog eq, pushed to +8dB at 60Hz would produce the exact same sound. I don't have one to test with.
I tested with VLC on the same machine and didn't hear this. But that's not saying much. VLC's equalizer may or may not be doing exactly what it shows on screen.
As another test I set MC DSP Output format to convert 96kHz to 44.1kHz. I still hear the exact same thing.
My gut feeling is that I'm simply hearing more of the 60Hz content that is present in that signal already when the EQ is engaged. I'm not sure.
An analog EQ or another highly regarded digital player with a 60Hz boost would be good things to double check this against.
dmitch77: It seems like you have several complete systems with different playback back ends. I suspect that your system that does not show the error has different speakers with less bass response. If it's not too hard, you might move the Mac from that system temporarily to plug in to one of the other systems where it's clearly audible. Then see if you can hear the same thing on that one.
Brian.
dmitch77:
--- Quote from: blgentry on August 16, 2019, 08:00:47 pm ---I hear this too.
An analog EQ or another highly regarded digital player with a 60Hz boost would be good things to double check this against.
--- End quote ---
It's telling, I think, that using MC's Parametric Equalizer - also in DSP studio - to do more-or-less the same EQ tweak does not cause this hum. E.g., Low-shelf, 100 Hz, 6 dB gain. It raises the bass, as much as you want, and the hum never happens. That seems to indicate (to me, at least) that it's not in the source audio, it's not in the downstream hardware. It's in the EQ.
Moving Macs around at my location is not practical. The speakers on the Mac where this does *not* occur are pretty good and I can turn it up pretty loud. Thanks for looking at this.
wer:
There would be an easy way to prove this, if the method works.
Grab a sine wave file, something like 1kHz. It will have no 60Hz content.
Run it through both equalizer types, and look at the waveform output of each, and see if a hum is being manufactured where none could have existed.
If this doesn't produce a hum, it proves nothing, because it might only happen when there's signal in that frequency range to process...
dmitch77:
--- Quote from: wer on August 16, 2019, 10:35:51 pm ---There would be an easy way to prove this, if the method works.
Grab a sine wave file, something like 1kHz. It will have no 60Hz content.
Run it through both equalizer types, and look at the waveform output of each, and see if a hum is being manufactured where none could have existed.
If this doesn't produce a hum, it proves nothing, because it might only happen when there's signal in that frequency range to process...
--- End quote ---
Good idea. I tried with 1k sine wave. No anomaly. Tried with pink noise, tried with silent audio. No anomaly in either case. There is something in that audio file I supplied that triggers the bug.
wer:
So when Brian heard this, it was out of the same file? Is that the one and only file that produces the anomaly?
I would then try this: convert the flac to wav and try again.
If there's no hum, it's the file itself and not the actual waveform data.
If it DOES hum, try applying an equalizer to the wav in Audacity, or some other high quality editor.
Remember, 60Hz humming could be a ground loop hum present in the actual recording.
But given the fact the peq doesn't reveal it, I think not. It would be interesting if some strange combination of data triggered a mathematical error in the geq code. That would only be indicated if there's hum in MC on wav but no hum from audacity. In that case, Matt would have to look...
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version