Hi,

removing the amps, power suplies, and everything else in the case of the BeoLab 3500 won't work because there are two bass units and two tweeters inside which are not connected via a crossover network to split the frequency ranges! Also the inbuild audio processing is responsible for the speaker protection. so this is no good idea.

Have you ever thought about using two BeoLab 4000 as rear speakers?

the can be mounted right below the ceiling and can be mounted in such a way that the "beam" downwards. A quick search here in the forum gave this

considering lost of options including Beolab 4s, 4000s as well as 15s. The thing is there is no power in the area to run active which is why I was considering using either ceiling mounted passives or stripping a 3500 and running it as two seperate passives with the amp in the x3400.

How about using the BeoPlay S8 set/the BL14-2 set?

MM

Its one of the options I looked at but cant seem to find the satalitles available.

The thing is Im already running 2x 10" enclosed subs with 10" passive radiators so have more than sufficient bass/sub base.

All the speaker output on the x3400 is via preout so the built in amp isnt being used. The location of where the rear/surround speakers need to go will make it difficult to get thicker rca cables through which again pushes me down the passive route and using the under utilised amp of the x3400.

My original though of stripping the internals of a lab3500 would remove the amp and crossover, but the avr would provide protection by limiting low frequency  to >100Hz and then I could use a passive crossover to take the >3.5k frequencies to the tweeter. 

Asthentically this would be the best option for me and would also negate having to drill ceiling holes which will look at odds with the existing downlighters

Well after much consideration I picked up a used lab3500 for next to nothing. Downloaded the manual and slowly set about taking the unit apart.

Was quite easy to remove the amplifier and other circuits and then install two seperate crossovers and adjust the wiring.

Whilst they may not be perfect the crossovers are 2-way sending >3kHz to the tweeters and a 12db cut off rated for 200w.

Hooking them up to the denon avr amp means I can adjust the volume of each channel to match the volume of the lab1s via Audyssey. 

Overall Im happy as I've maintained the look of the existing system and with the lab3500 stripped its much lighter in weight and fills the rear adequately with rear surround bounced off the wall.

Not sure wether to keep the original internals from the 3500 just in case or put them up for auction.