Electronic bandwidth limiting for bassreflex speakers?

[voodooless]

Excuse my ignorance, but doesn't your average home theater receiver with subwoofer out(s) do the same thing. A little research shows Denon and I believe other brands use a 24 db/octave high pass filter which typically can be set at different frequencies between 60 hz and 200 hz although some are fixed at 80 hz.

We’re talking about a high-pass filter on the subwoofer, not the mains. Typically that would be between 20 to 40 Hz. An AVR doesn’t typically do that.

 

[markstein]

No, not even when using a standalone linear phase HPF using 24dB/octave slope
It is the question of how the filter was implemented - the best implementation from a pre-ringing perspective (at least that I am aware of - and believe me I have tried many) is thEQorange

Well, per my understanding, a linear phase filter always has pre-ringing, no matter how you "implement" it (I do not understand, what you exactly mean with your statement about implementation).

Only if paired with a perfectly aligned complementary linear phase filter, the pre-ringing cancels out (perfect linear phase x-over).

Now place subs in your room, place mains in your room and try to get a perfect x-over at various locations in this room - good luck!

The question is what is more audible in the end: pre-ringing by imperfect linear phase sub/main x-over or increased group delay but no pre-ringing by minimum phase sub/main x-over. I am using the latter.

Regarding high pass filters to limit the main speakers without sub: I would never use a linear phase filter as HPF, not suitable for this use case IMO.

 

[ppataki]

Well, per my understanding, a linear phase filter always has pre-ringing, no matter how you "implement" it (I do not understand, what you exactly mean with your statement about implementation).

Only if paired with a perfectly aligned complementary linear phase filter, the pre-ringing cancels out (perfect linear phase x-over).

Now place subs in your room, place mains in your room and try to get a perfect x-over at various locations in this room - good luck!

The question is what is more audible in the end: pre-ringing by imperfect linear phase sub/main x-over or increased group delay but no pre-ringing by minimum phase sub/main x-over. I am using the latter.

Regarding high pass filters to limit the main speakers without sub: I would never use a linear phase filter as HPF, not suitable for this use case IMO.

Apparently I was not clear enough. I was referring to the audibility of such filters.

If you try for example a 24dB/octave slope linear phase HPF filter in different linear phase VST plugins, such as CraveEQ, Fabfilter Pro Q-4, GrandEQ, thEQorange and many more and measure the output signal either digitally using for example PluginDoctor or with a measurement microphone in the listening position, you will notice that the step response curve and the wavelet diagram (these can be used very well to measure pre-ringing) will look pretty different from each other with each plugin.
Some will have more pre-ringing, some will have less pre-ringing - some will be more audible, some will be less audible

After trying many of such plugins I can safely say that the way it was implemented in thEQorange produces the least audible (=practically inaudible) results.
Either when using the HPF filter standalone, or as a crossover combined with an LPF

Regarding high pass filters to limit the main speakers without sub: I would never use a linear phase filter as HPF, not suitable for this use case IMO.

It is indeed pretty suitable since a linear phase HPF will never increase the group delay....
So neither the pre-ringing, nor the increased group delay (since there is none) will be audible

 

[gberchin]

Some will have more pre-ringing, some will have less pre-ringing - some will be more audible, some will be less audible

Then they are not implementing the same filter. Different implementations of the same filter produce the same results.

The impulse response of a linear phase filter is symmetrical in time, so pre-ring always equals post-ring (there may be a sign flip if the filter is odd-symmetric). If it is not symmetrical, then it's not a linear-phase filter.

=practically inaudible

"Practically inaudible" is not the same as "inaudible".

a linear phase HPF will never increase the group delay

Nit-picking, but a linear-phase filter of any kind increases group delay equal to half the filter length. The important factor is that the group delay does not vary with frequency.

 

[YSDR]

A little research shows Denon and I believe other brands use a 24 db/octave high pass filter which typically can be set at different frequencies between 60 hz and 200 hz although some are fixed at 80 hz.

That's a low-pass on the AVRs, not a high-pass. It's for crossing over to the main speakers.