Using the crossovers in your sub AS WELL AS in your receiver? (1 Viewer)

[BruceD]

Nope, you are right again, standing waves cause peaks and nulls as well as other things like multiple sources of the same signal (2 subs, sub+mains LFE settings, etc.).

The basic objective is to determine the best speaker and sub locations in conjunction with your room size and listening location to minimize the nulls and peaks from all sources. This is not a simple job by the way, but it just depends on how deep you want to dive in to get the results that satisfy you.

In my case I'd probably be considered anal because I bought a textbook (F Alton Everest's "Master Handbook of Acoustics") first, then did lots of experimenting with the ETF software to get an idea of what is going on with the room/speaker interface before getting something I liked.

 

[Kevin C Brown]

Bruce:


Which *is* actually - 6 dB for each filter at the crossover point.

 

[Edward J M]

When I answered this previous question with a succinct "yes", I thought you were asking whether two filters which are both -3 dB at the xo will sum to unity (which is true). I didn't realize you were also asking specifically if the 4th order LR should be -3 dB at the xo frequency (which is not true).

 

[BruceD]

Kevin,

There are a number of issues with crossovers as you point out (I don't consider aholics a credible source). The point is most HT processors are using 2nd order Butterworth for HPF and 4th order L-R for LPF. This combination depends on the speaker's rolloff providing an additional 2nd order Butterworth at the xover frequency to the high-pass side to get the correct implementation through the crossover boundary.

I don't agree with this quote from that article, because most HT processors don't provide this.

If the speaker doesn't provide this 2nd order rolloff at the xover frequency chosen (and most ported speakers don't) then you have issues at and around the crossover with SPL deviations (peaks and dips) not even considering the phase anomolies.

IIRC, a 4th order L-R is a "constant voltage" or CPC filter and not an APC as you quoted from the article. I may have my terminology screwed-up, so I will go back and check.