The Linkwitz-Riley Disaster

[guyman]

So for a long time I have fooled with different butterworth/linkwitz riley crossovers and have not had much luck. I understand how to wire one up, I understand how to run the allpass filters to phase compensate, I understand to compensate for the 6.02/db dip at the XO for every 12db/slope.

I built my own out of butterworths, great phase response - no latency (other than phase) no noticeable distortion - but couldn't get the response correct due to the 6.02 dip and my lack of getting the peak band / Q width perfect for the compensation at the XO.

I've read up a bunch, and found the Dozius one on the filter, as far as I can tell, it works great EXCEPT the cutoff frequency is not full range, and only goes from 1k ^ (what gives?), and only 2nd & 4th order are available (I want steep controls !)

If someone could please come to the rescue, I'd love to finish the rest of my device but the end of the week, and there's a lot more to do. I wanted to do it alone but this Linkwitz-Riley XO has been a headache for too long.

I just need the perfect LWR crossover.

[guyman]

ps. the 4th order is more than likely all I would ever need as I'm pretty sure anything more would introduce pre ringing to seriously mess up transients... I don't know. Please enlighten.

[martinvicanek]

Here is a universal band splitter. Choose from 1 to 10 poles. The even ones are Linkwitz-Riley types with two stacked Butterworths, whereas the odd ones are single Butterworths, therefore they have a sharper knee.

For the inclined reader: the Reinsch biquads are my own design which handles low frequencies better than the direct forms.

Edit: the Reinsch biquads had problems with denormals, therefore replaced them with ZDF filters which also perform well at low frequencies.

Have fun!

[guyman]

King Martin.

[guyman]

You really just made my week good sir. Happy Halloween.

[BobF]

Hi Martin,

Thanks, these filter are nice, but can the freq be modulated (lfo or adsr)?

Many thanks in advance, BobF.....

[guyman]

Uh oh bobby up to something real nice.

[martinvicanek]

can the freq be modulated (lfo or adsr)?

Updated my post above.

Thanks for the comments, glad you like it.

[wlangfor@uoguelph.ca]

Here is a universal band splitter. Choose from 1 to 10 poles. The even ones are Linkwitz-Riley types with two stacked Butterworths, whereas the odd ones are single Butterworths, therefore they have a sharper knee.

For the inclined reader: the Reinsch biquads are my own design which handles low frequencies better than the direct forms.

Edit: the Reinsch biquads had problems with denormals, therefore replaced them with ZDF filters which also perform well at low frequencies.

Have fun!

Thank You