Dahlquist DQ-1LP crossover owners

Horacio, I just looked it up on the First Watt website, to refresh my memory. The B4 is a regular x/o, but there is a special version of it---the B5, made especially and specifically for full-range drivers with woofers in open baffles. Go to the First Watt site for all the details.

Regarding the Dahlquist DQ-LP1 and the Magneplanar Tympani-IV and IVa loudspeakers, I remember why the Tympani requires the 3rd order (18dB/octave) low-pass filter that the DQ-LP1 provides rather than the 1st order required to compensate for the 6dB/octave roll-off caused by the dipole cancellation found in all open baffle woofers: It is to create the correct relationship between the Tympani’s woofer panels and it’s midrange/tweeter drivers, in terms of phasing.

By the way, the T-IV requires a 1st order-6dB/octave high-pass filter at 500Hz, but the T-IVa a 2nd order-12dB/octave h-p filter at 400Hz. The Dahlquist provides the former, but not the latter. That’s one reason I got the First Watt B4---it provides 1st-2nd-3rd-4th order filters, both high-pass and low-pass, from 25Hz to 3200Hz, in 25Hz increments. Incredible!

He said that the B-4 is a two-way crossover. If you want to have three-way active crossover system, you will need two B-4’s and connect them in a cascading fashion. A “6 dB boost” of sorts can be achieved by attenuating the top-end(s) and having a linestage preamp with more gain (if needed) or power amps with more sensitive inputs (if needed).

The B-4 and set up is complex. I agree with Nelson Pass who has said that with active crossover a person “needs to know where they are, where they are going, and when they’ve arrived.” Crossovers with millions of combinations are not for everyone. I agree with him after reading the owners manual.

I will go with the Rythmik OB.

Happy Memorial weekend.

Cheers.