Recommendations for electronic crossover.


I am bi-amping my B&W 804 matrix speakers with a 50 watt per channel tube amp for the top and a 200 watt SS for the woofer. Any suggestions for reasonable priced crossover? I have been told Merchand (?) makes a good one.

Thanks!
jpahere
@dhl93449

Regarding the subject of active XOs, it is almost impossible to find one that is built without op amps. Bryston is the only company that comes to mind that produced HP and LP versions with discrete Class A circuitry, and I do not recall if these are still in current production. In any case they are not cheap, and if you need more than just a single XO point (two way system), the costs mount up fast.

This stance is a quick way to discard active XO’s when in fact they could be beneficial to a passive solution - even with opamps and A/D to D/A conversion being introduced in the signal chain.

What’s the bigger picture; do the comparison and forget for a while the drawbacks mentioned to hinder the fuller realization of an active XO, if they’d even be that relevant compared to the negatives of a passive config., and then see. My take with an XP-series Xilica XO is that it trumps excellent passive XO’s in the three set-ups I’ve heard so far - quite easily. The sound in all cases went from slightly diffuse/smeared and soft to more clear, refined, transparent and dynamic going from passive to active.

A second suggestion of the First Watt B4 (designed and built by Nelson Pass). The factory-built edition is no longer in production, and used examples rarely come up for sale, so be prepared to wait. A kit version is about to be made available, I believe.

The B4 is a discrete design, no opamps, no ic’s. It listed for $1500, sold for about $1200. Really versatile: two channels of 1st/2nd/3rd/4th-order high and low-pass filters in 25Hz increments from 25Hz to 6375Hz, level controls for either the high-pass or the low-pass outputs, switchable.

I have successfully used the DriveRack dbx PA2 LMS (loudspeaker management system) with vintage gear and some modern speakers. It works quite well as an external xover for 2-way and 3-way speakers and is affordable. The only downside is that it requires some time and patience to setup and it looks like Pro gear (which it is) and not home audio gear. I mount it backwards in my audio rack and it's practically invisible.

Audio Nirvana published a great article about restoring vintage Altec Lansing Model 14s and described how they used this box to overcome some fundamental design flaws of the 14s. I followed their recommendations and it works great. Here's a link: dbx DriveRack PA2: The Future of Audiophile Systems

Although I don't find external EQ and xover to be necessary in most situations it has always improved the sound of whatever speakers/rooms I have used it.

phusis
Its all a matter of degree. Whether an active XO system using IC op amps sounds better than a passive system with the best Mundorf or other high end caps, inductors, and resistors may be arguable. 

But it makes no sense to me to place an EQ/XO having IC opamps between a discrete component preamp and discrete component power amps. I actually tried that with a Phonic i7600 op-amp DSP between my Parasound JC2 and two JC1s when trying too chase down a frequency balance issue (and it was good for that), but the sound quality through that Phonic unit did not sound as clean and detailed and the system with a passive XO and the Phonic removed. 

I am probably in the camp leaning toward an active system, but will not compromise in using IC op amps vs discrete class A circuitry. Every time I have made a comparison of products with IC op amps vs discrete, discrete always wins hands down. I think both Nelson Pass and John Curl would agree with me (along with Bryston). So I am in the process of designing and building an all discrete 4rth order Linkwitz Riley LP/HP XO system for the PAP Horn1 speakers. It will also have discrete op-amp gyrators for a parametric EQ function. Expensive, time consuming, and rather large, but I think it will be worth it.
Well, I finally finished my discrete Class A XO project. I used my own design discrete op amps, based on an early Spectral design modified with Nelson Pass inspired JFet output stages (instead of MOSFET stages as originally used by Spectral). I am using 4rth order Linkwitz Riley filters for both HP and LP filters and the drivers integrate smoothly

Took out the gyrators as I really did not need parametric EQ with the Voxative drivers (switched from the Horn).  

System is now sounding better than it's ever sounded. So that confirms that the active XO system has merit in principle, and the class A discrete designs in practice.