5.25 in. MTM +SUB vs. SINGLE 8or10in. + SUB

I am tying to put together a speaker kit anybody with experience in either design could give benifits or drawbacks on either? I tend strongly toward the MTM design. I will not use a midrange driver. All posts are greatly appreciated.

sorry, I'm confused.Doesn't the M in MTM stand for midrange? How are you not going to use one and still use the MTM terminology?
If you are going to be using a sub, then most definitely keep the midbass units at 6.5" or less, preferably in the 5-6" range. The upper midrange response is vastly better than an 8" will ever have, and you don't need the drivers to go that low in the bass. If you want a specific recommendation, use the Vifa 13WQ, it is a classic and still one of the best midbass units out there. Look up the Ariel by Lynn Olsen (I can't recall the website), it is one of the best uses of this driver and has a ton of info and support. Even if you don't end up doing this exact kit, it is still a good way to start your education.
Sorry, I had a brain hiccup. Lynn Olson's website is www.aloha-audio.com, the Vifa driver is P13WH.
MTM = MIDbass/TWEETER/MIDbass Karls heres my choices FOCAL 5K4211(5inch poly/kevlar) or 7K4411(7inch poly/kevlar) CABASSE 17M18(6.5 FOAM) SEAS W17E(6.5 magnesium) or W18E(7inch) I'm confident the MTM design is the way to go. Do you suggest the 6.5 is the IDEAL size M/B? I would tend to think the 5inch Focal is too small but could the 7 inch Focal be acceptable? Tough choice all 3 are SUPERIOR drivers! I tend toward the Focal 7K4411 poly/kevlar. any votes well appreciated!
Research leads to the following: PHL1230 6.5 MIDWOOFER 40-4000hz.@93db!!! + RAVEN-2 RIBBON TWEETER 1800-32000hz.@95db.!!! Final choice. (The awesome R-3 is 500-25000hz@100db.!!!! REPEAT 100db WOW! Nothing less than a miracle! But$$$1600EACH! Well worth it!)
I don't recognize PHL1230. Is this Phillips or what? One very important caution: ALL the drivers you have suggested have extremely nasty resonance peaks in their upper range, which is going to require you to use very high-order crossover networks to remove, which is a real can of worms. Having done this for a long time, I can tell you that without access to thousands of dollars of measurement equipment, you will be FAR better off choosing a midbass which is relatively flat through its upper range. This means no Kevlar, no carbon, and definitely no metal cones. Just my 2c, obviously others will disagree. Re the Ravens, haven't tried them but they probably work well IF you can get them to integrate with the cone drivers, not an easy task. You have the additional problem that they are much taller than typical tweeters and in an MTM they will cause problems due to the wide separation of the two midbass drivers. Again, if you want to have some chance of getting good sound, best to stick to good-quality soft dome tweeters since they are the easiest to work with.
You can download the PHL info on ZALYTRON.com. Its not any of the 3 materials you mentioned. Trust me on this one its the BEST. BYW like kora and Jadis AudioAero PHL is made in France. the Ravens are reputed to be the best. I don't doubt it. I'm sure someone is going to shout "now hold on ..not so" You got your favorite i've got mine. I posted a thread "21st century speaker?" got alot of puzzled comments. honestly i did not know where my search would lead. Just know that i was DISGUSTED with the speakers on the market! The ol' "seek and you will find" is so true... 21ST century drivers make a 21ST century speaker.
Please change the 5.5 inch to 6.5 inch Thanks
lately i've been giving this mtm design some thought. GENIUS!! Think about it.... Why try to extract low hzs from a single 8 or 10 inch woofer. let a great sub (CABASSE 12 or 16 ) worry about the below 40 hzs and the dual 6.5's can do the rest. think about it. with dual 6.5's you get more than twice the surface area over a 10 and almost 2x the obsolete 12. dual 6.5's give a relaxed presence to the many different midbass hzs. thrown at the driver. the 10 is doing his very best but some complex music has got him comming and got him going. the 21st century speaker is begining to take shape. heck its here! thanks to a guy by the name DR. JOE APPOLLITO. the question of superior dome tweeter vs superior ribbon tweet i can't judge until i hear the RAVEN-2. the superior dome tweets to do battle with the RAVEN-1 and RAVEN-2 would include the SEAS MILLINIUM the top FOCAL ADT CABASSE. the winner takes on the PHILIPS R8T isodynamic. got a note from a guy that belongs to a group that designs equipment and tests to determine a drivers qualities. really complex stuff. he said he's can't stand when someone votes big on one driver and shoots down another. then he lists about 10 super high tech variables that can affect a drivers potential. i agree with him to some extent. but a lab is not going to price its superior driver about the same $ as its entry model. ain't no way. AND we all know that some amps and cdp sound superior to others in the same price range. same with drivers. some are better than others in simular circumstances. so take time to find out which drivers you're buying. don't just buy by speaker name. buy with knowing WHICH drivers your getting. or better choose your own. yep thats what i'm talking about. heck you can't design your amp or cdp, you buy after researching the product. same should go for THE MOST IMPORTANT COMPONENT IN EVERYBODY'S SYSTEM. when you go buy a speaker from your local hifishop ask him what is the name and model# of the drivers. he don't know! IF a commercial lab DID offer these same drivers in a design you're looking to fork out $5K to $15K. and would they sound as good?? i got my opinion. you may think its bias but first go listen to your speakers. all right blast away
Got it! Made my choice. With a bunch of help from THE WIZARD OF ZALYTRON!!