Crossover upgrade?

Have B&W Concept 90 CM1's. Very small 2 way. Circa 1992.Mint condition. Very interested in upgrading the crossover as these are enjoyable in the small room used (supported with 200 watt Spectral amp). How do I approach this?
I just had Chris at Partsconnexion put a kit together for my Kappa 9's. Supply him with the schematic, your budget, and away you go. It can be better than stock or just a lot more expensive. A rebuild will always be an improvement. You definitely need knowledge or someone knowledgeable to direct where to spend the money. However with a two-way I would go all out.
Csontos thanks for the Parts Connection tip.
I've heard of them but they hadn't come to mind for this.
I am a believer in crossover upgrade as it results in very high improved performance at a much less cost , and found it cheaper ( less costly ) way to upgrade than to buy a new pair of speakers.
Simplest way is to replace and upgrade on quality of capacitors , resistors, internal wiring , go value/rating strictly matching with the old ones, but to go for much higher quality.
You can do it with help of some local electronic shop guy . Sending all the way to Canada may become expensive. Replacing these parts is easy , but if you have damaged drivers and want to replace them also may be you can think to send them to partsconexion . Another place to consider is parts express ( I think I recall it right) .
For DIY’s, I’d consider adding active crossovers as a permanent test component. Testing various XO points with passive units can be time-consuming and expensive. Active XO’s are ideal to quickly “dial-in” and sound test different crossover points. Some offer 2-3 way stereo in addition to 4-5 way mono.

For a 2-way cabinet, knowing the recommended lowest crossover point for the drivers is critical to prevent damage. For example, if your tweeters are recommended at a safe 2500 Hz minimum XO, and a smaller bass driver plays relatively flat up to 5-8 kHz, you can safely dial in different XO points at 2500, 4K, 5K, 6.3K and 8K. Simply listen to different XO points to determine the best sounding XO point for the two drivers musically while playing your favorite musical or test tracks.

If you’re unfamiliar with active crossovers, the processors L/R analog outs go to the L/R active crossover inputs. The active crossovers spilt your processors single outputs into two outputs for connection to separate amps for the bass and tweeter sections. A 2-way cabinet requires two amp channels per cabinet, a 3-way requires 3 amp channels per cabinet, etc.

One method is looking at the spec sheets on your drivers. Look for the flattest frequency responses and matching sensitivity ratings of each driver. Example: If 8 ohm 95 dB sensitivity bass drivers play flat from 60 to 6K, and 8 ohm 95 dB sensitivity tweeters play flat from 2.5 kHz to 16kHz, the best level control for both drivers is a likely a XO between 2500 to 6000Hz.

Once the best XO point is determined using active XO’s, buy separate quality passive crossovers and return to single amp channels per cabinet. Alternately, keep the active crossovers and separate amps for each driver. When going fully active XO’s, many recommend extra protection for the tweets in case of a upstream component “pop” while switching sources or when turning components On/Off.

A passive, inline 2000-2500 Hz high pass capacitor will protect the tweeters from any sudden spikes from the dedicated amps. Active XO’s often use 4th order Linkz Riley (spelling) filters, too, and well-regarded by many.

Parts Express, Madison Sound, and Meniscus are good online sources for DIY ideas and tech support.

Hard to get any detailed info on those. I do remember that B&W likes high crossovers around 4K. You really need a goal to know which way to go.

If your crossover looks anything like this...

... I'ld focus on replacing those electrolytic caps (white rectangular, mostly labelled 3.3) with same value poly's. The stuff on the bottom right is protection circuitry. Don't get carried away with expensive boutique caps on nearly antique speakers. However, if you tell someone like Chris at PartsConnexion what you want to improve, he will have suggestions. PCB soldering and unsoldering is usually not a area for novices.