TOPIC:

Interesting stuff going on here! Thanks to Charlie for sharing his great work and I think that a lot of miniDSP users will be interested in hearing more of your progress.

Should we start a dedicated thread to your good work Charlie? Maybe easier for users to find the information and we'll gladly put it as a sticky being a topic that I'm sure our community will enjoy.

Happy holidays to all,

DevTeam

Anybody implemented this in minidsp

S. Lipshitz and J. Vanderkooy linear phase crossover

It's stretching quite a bit for the authors/designers to call those linear-phase crossovers.

If the question is, can you create a linear-phase crossover with the miniDSP? The answer is "yes", but only in the case of a true first-order acoustic crossover. Anything else doesn't satisfy the linear-phase requirement of constant group-delay and a perfectly flat phase response with the outputs summed together.

This question is off-topic for this thread anyways.

Cheers,

Dave.

Hello, Dreite!
I think You are a little wrong about linear phase crossover. You can make it also with 2nd order.
You can see such filter based on real speaker on picture in this post. In comparison to standart LR12 (etc filters) we have peaks near crossover regions on vertical axis instead of dips. But maybe it is better, who knows . Also we need speakers with more bandwidth and lower distortions.
Don't ask how it sound. I still didn't listen to this.

cloud.mail.ru/public/2gij7rLmvhFZ/lin%20phase.jpg

Well, it's a topic of debate.....depending upon the conditions we define for the requirement.

A person could make a good case that linear-phase operation is only possible with headphones....and not even all of those.

Your example doesn't show linear-phase response. Multiple phase wraps which appear to be time-of-flight or some other pure delay built into your measurement. If you back that out it appears your phase response might be fairly flat.

Dave.

dreite wrote:

Well, it's a topic of debate.....depending upon the conditions we define for the requirement.

A person could make a good case that linear-phase operation is only possible with headphones....and not even all of those.

Your example doesn't show linear-phase response. Multiple phase wraps which appear to be time-of-flight or some other pure delay built into your measurement. If you back that out it appears your phase response might be fairly flat.

Dave.

There is Impulse response in my measurement, so this wraps only due to distance delay. I added here a picture of 500Hz square (filter on tweeter was a little different). And ofc. lower 200hz it will be closed box with its delay. But what about subwoofer with Linkwitz correction and such filters as mine on upper side? There will flat Group Delay for very low freq. without much delay 40-1000 ms if we compare this type of IIR filters to FIR filters with high slopes.
And another interesting trick - WMTMW. Side drivers M - M; W - W; will have dips below axis on vertical plot. Such thing will compensate amplitude rise and give us almost flat vertical plot.