Dirac filter creation: Best way to treat high-frequency roll-off

[wgscott]

For whatever reason (room, Class D amp, ?), above about 7kHz I get a significant roll-off. I'm making some filters and adjusting the default window. (My sub doesn't do much below 28Hz either, thus the left-hand side adjustment.)

 

By default, Dirac tries to correct the high-frequency roll-off, but this results in a steep cut-off around 18kHz in the target curve:

 

 

I can eliminate Dirac's cut-off completely if I only correct to 7 kHz:

 

 

I'm going to try listening to both, but from the point of view of doing further up-sampling and/or filtering in the DAC, is it better to avoid the steep cut-off at the expense of correcting only to 7kHz, with the idea that having the steep cut-off could produce artifacts in the audible region, or is it better to stick with the steep cut-off that results from application of the default correction curve?

[TomScrut]

I would try leaving Dirac on above 7k but move the point back to 7k to get your roll off.

[wgscott]

Apart from putting a roll-off in the digital filter (which I would think it would be better to avoid), how would this differ from the second option?

 

BTW, I can't hear the difference between the two filters posted.

[TomScrut]

Apart from putting a roll-off in the digital filter (which I would think it would be better to avoid), how would this differ from the second option?

 

BTW, I can't hear the difference between the two filters posted.

Because frequency response is only half of what Dirac does. The impulse response would not be active above 7k. But I would be surprised if it makes a big difference

[wgscott]

I guess what I didn't make clear is this: Is the roll-off in the first picture problematic if one wants to do further up-sampling and filtering in the DAC?

[TomScrut]

Can't help with that I'm afraid. But I find it sounds better with the roll off similar to yours because it can sound shrill on some songs that have lots of treble content

[wgscott]

Can't help with that I'm afraid. But I find it sounds better with the roll off similar to yours because it can sound shrill on some songs that have lots of treble content

 

Actually, that does help.

 

Thanks very much.

[TomScrut]

Actually, that does help.

 

Thanks very much.

As in I keep Dirac filtering the full 20k but move the last point to coincide with the speaker roll off

[SteveS1]

I've seen roll off from 7-8khz on quite a few graphs, I wouldn't say it was abnormal.