B&W Matrix 800: Bi-amping thoughts?

From what I can find, the woofer crosses over to the midbass at around 300hz, which is smack in the middle of both male and female vocals, which will make it more critical to blend well between two amps. 

If done well, it could help improve the clarity of the midbass/tweeter amps by relieving it of low bass duties, but will require a woofer amp with not only ample power and the ability to handle large woofer excursions, it’ll also need to have good lower midrange sonics to get it blend well.  You’ll likely want the ability to blend the gain of the two amps to match.  

Please keep us posted on your progress.  

@musicfan2349 It was initially Meta AI. 

"what are the crossover points on the B&W Matrix 800 speakers

The B&W Matrix 800 speakers have separate crossovers housed in the three separate cabinets. Each woofer enclosure has a low-pass crossover dedicated to the driver inside, and the central cabinet houses the mid/high crossover boards. The crossover points are approximately at ¹:

• Low-Frequency Crossover (Woofer to Midrange): around 300 Hz, where the woofer’s output transitions to the midrange units.

• Midrange to Tweeter Crossover: approximately 3 kHz, where the midrange units’ output transitions to the tweeter.

It’s worth noting that some users have modified their B&W Matrix 800 speakers to use active crossovers, allowing for bi-amping. One option for this modification is the KBX crossover designed by Dan D’Agostino, which includes custom crossover points and a bass alignment filter ² ³."

I found that Aurel Hifi as well as hifiwiki.com called them "transitional ranges" of 300hz and 3,000hz.

https://auralhifi.com/products/vintage-bowers-wilkins-matrix-800-rosewood-speakers-installed-new-satori-beryllium-tweeters-refinished-cabinets-na-matrix

https://hifi-wiki.com/index.php/B%26W_Matrix_800

I also saw another AI blurb on Google that stated 380hz and 3,000hz that referenced DIYAudio.com and Stereophile. 

Ferro fluid is probably best off being changed.  I did mine a few years ago after 35 years.  It made an audible improvement.  It’s not a bad task, and there are helpful vids online.

The amps do not need to have matching power output if  you do a horizontal configuration with one amp on the bottom and one amp on top, as it sounds like you’re planning to do.  It’s very common in the type of setup to use a more powerful amp for the woofers.  I’m using 100 wpc on the woofers, and only 17 wpc on the midbass/tweeters.  You will likely need a method to match the gain so that they play at the same volume, unless the amps just miraculously happen to have the same gain.  There are a few ways to match the output. 

Every situation is a bit different, so no two bi-amp setups are alike.  Don’t worry if you do somethingn different than other bi-amp setups you see, because you’re starting from a differnent place with a different rig than anyone else. 

In my case, relieving the smallish tube amps from woofer duty really made the midbass/treble clearer and more dynamic.  The solid state amp also has better dynamics and control over the woofers, so that improved too.  Also in my case, I added an active low pass crossover for the bass amp @ 63hz, which gave me a separate gain control for that amp, but I also bypassed the low pass passive crossver from the woofers.  (For you that could be a significant mod from the stock crossovers because of how elaborate they are, but I’ve read of people doing it, so some info is out there for you).  Along with the active low pass, I also installed an inline high pass for the tube amps, but my speakers had only a natural acoustic rolloff for high pass and no passive crossover mods were necessary.  (different situations.) 

It’s fun to do, and there’s definitely some potential benefit.  A lot in some cases.  I approached my bi-amping in phases as I went a long starting with a vertical configuration (monoblocks).  Then added the solid state amp later (horizontal), so it’s hybrid vertical/horizontal. It’s also tube/solid state hybrid, and active/passive hybrid.