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[BCZ]

So I've been trying to track down why JRiver is clipping with my DSP settings for my active crossover, and I think I found why. It is a bug on how the subwoofer limit operates.

I am using a large amount of bass boost in DSP studio, but I use a subwoofer limiter to prevent the bass from exceeding -13dB (in order to protect my speakers). The subwoofer limiter audibly works to prevent that level from being exceeded, but it doesn't actually reduce the level of the signal within the DSP chain, and that causes clipping.

To see this, copy the left channel to the rear left channel, then set a -50dB subwoofer limiter on the rear left channel, then blast a strong 50Hz sine wave into the left channel. Audibly, you'll hear the speaker stop getting louder as you turn up the volume. However, if you look under analyzer, you see that the rear left signal will go past the -50dB threshold as if no limiter was placed at all. Because of this, the peak level meter will reach 100% x dB quicker than it should, where x is the amount of bass boost that is applied in the DSP chain.

The proper behaviour should be that the signal should be attenuated by the limiter when the limiter is engaged. This way, an arbitrary amount of bass boost can be used on the LFE channel without clipping as long as a limiter is placed to prevent the total signal on the LFE channel from exceeding the threshold.

This is a really important issue for me, could a developer please confirm that this problem is reproducible? As a developer myself I know how long it'll take to get to fixing this bug, but it'll at least comfort me knowing this is on the bucket list.

Thank you

[mattkhan]

To see this, copy the left channel to the rear left channel, then set a -50dB subwoofer limiter on the rear left channel, then blast a strong 50Hz sine wave into the left channel.

I don't see that behaviour using the suggested method, the limiter works as expected. I suppose there must be something else in your configuration that causes such behaviour so I suggest you post your complete dsp studio config.

[BCZ]

Can you tell me how to export the DSP studio configs? There are over 50 filters in there. I won't upload the whole thing (unless you want it), I will upload the minimum number of filters that will reproduce the problem I have on my end to make your work easier.

[mattkhan]

I don't know of an easy way to share that config other than using a library backup, i.e. use the save/load option in the dsp studio window to save the current settings then do a library backup, now open that zip and you'll see a Settings/User Settings.ini, in there you'll find config blocks like [Zone Presets\\<DSP preset name>\\Tempo & Pitch] which describe that preset. It should be enough to just post the relevant ini block.

[Matt]

Would you send a library backup to matt at jriver?  Thanks.

[BCZ]

EDIT: I don't think this is the problem. I need to dig deeper. Sorry for the false alarm this time. I can't even reproduce the clipping right now for some reason. Will be much more thorough next time I post something.

Interesting, looks like I cannot reproduce the scenario I described either. Let me diagnose this more.

Here is a link to my library backup that will do the phenomenon I described

https://www.dropbox.com/s/wpd262w580r7f7l/Clipping.zip?dl=0

There is some fairly ridiculous settings, like a 40dB bass boost with a -33dB subwoofer limiter. With this setting I can see the SL and SR (where the bass channels are) at -3dB at Analyzer even though I specified a -33dB limiter.