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EQ Anomaly in DSP Studio

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dmitch77:
I've found an anomaly in the EQ section of the DSP studio. I have a sound file, linked below, which makes the EQ section behave in a manner I consider to be incorrect in some configurations.

The source audio is just "clicks" (created by wood blocks) along with reverb (room ambience). Here is a link to this file:

https://www.dropbox.com/s/jop2s9sh6f1es9o/EQ%20Test.flac?dl=0

It's 39 seconds of this audio, in FLAC format, 96 KHz 24 bit.

When EQ is enabled in the DSP studio and the 60 Hz band is boosted at 4.0 dB or more, an anomaly is clearly audible: there is a 60 Hz hum in the reverb tails of most of the "clicks". Turn off the EQ, or set the gain for the 60 Hz band to zero, and you don't hear that anomaly. I'm pretty sure that there is no 60 Hz hum in the audio file; listen to it good and loud with the EQ off. The reverb tails are just white noise.

This anomaly occurs on 2 out of three systems on which MC is running. (MC 25.0.81 on macOS 10.14.5 in all three cases.) The two systems on which the anomaly occurs have high quality DACs - 96 KHz 24 bit - one connected via USB, one via HDMI. The anomaly happens whether MC is configured to send the output directly to the outboard DAC, or to the default core audio output which is then directed to the DAC. The system on which the anomaly does not occur has a 44.1 KHz / 16 bit external DAC, and the anomaly does not occur regardless of how the audio is sent to the DAC (directly to the DAC by MC, or via default core audio device).

System 1, anomaly occurs
Late 2013 iMac, macOS 10.14.5
DAC is Focusrite Scarlett 18i20, 96 Khz 24 bit, connected via USB
MC 25.0.81
  - audio out directly to Focusrite : error occurs
  - audio out to default Core Audio, default is set to Focusrite: error occurs
  - audio out to default Core Audio, default is set to internal speaker: error does NOT occur

System 2, anomaly occurs
2014 Mac Mini, macOS 10.14.5
DAC is Marantz SR7009 AVR, 96 KHz 24 bit, connected via HDMI
MC 25.0.81
  - audio out directly to Marantz : error occurs
  - audio out to default Core Audio, default is set to Marantz: error occurs

System 3, anomaly does not occur
2017 27" iMac, macOS 10.14.5
DAC is low-cost 44.1 KHz 16 bit connected via USB
MC 25.0.81
Anomaly never occurs

dmitch77:
Giving this a bump since it got no replies. It was actually intended as a bug report. JRiver folks - is there any chance that someone might get a chance to look at this one (and maybe fix it)? Let me know if there is any more info I can provide. It's 100% repeatable. Thanks.

mattkhan:
 if the issues occurs only on certain downstream signal chains then how can it be a jriver bug?

It is a bit difficult to follow the description though, have you considered capturing the output stream so you can show the actual output Vs the expected clean output? This would show exactly what the distortion was

dmitch77:

--- Quote from: mattkhan on August 15, 2019, 05:11:11 pm --- if the issues occurs only on certain downstream signal chains then how can it be a jriver bug?

It is a bit difficult to follow the description though, have you considered capturing the output stream so you can show the actual output Vs the expected clean output? This would show exactly what the distortion was

--- End quote ---

The problem happens when MC is outputting 24 bit 96 KHz audio, and it happens on two different platforms in this situation. It doesn't happen when MC is outputting 16 bit 44.1 KHz. The problem only happens using DSP Studio's EQ. (And not, for example, when using DSP Studio's Parametric EQ.) You don't see how this can be a JRiver bug?

I'm not sure I have the tools to capture the audio output to "show the actual output". What do you suggest for this? And what do you suggest for showing the "expected clean output"?

It's really easy to reproduce. Just play the audio I provided thru a hi-res DAC, boost the 60 Hz EQ by 4Hz, and listen. The problem is unmistakable. I'm pretty sure that if you try it, you'll hear it right away. Let me know if you need more info to repro.

Thanks!

JimH:
Can you take a look at this thread?

https://yabb.jriver.com/interact/index.php/topic,120675.0.html

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