MTM Drivers- Audax 8" vs 6.5"...

[HTRookie]

Hello Gentleman,

I am slowly plodding along planning my HT speaker project. This forum has been very helpful.. As so many of you have suggested to other rookies-I will go with a proven design, and not rush to get in over my head the first time around..

Since many of the MTM designs seem to use two 6.5" mid-bass.. I would appreciate some feedback on the idea of using two 8" Audax AM210Z2's along with an appropriate tweeter-yet to be chosen. This appears to be a good quality driver, and should provide more bass than the 6.5" with slightly better efficiency.

I am looking to build high quality speakers that while not earth shattering, should easily beat anything remotely close to what I could afford to buy ..

My budget for the drivers and crossover components(subwoofer, 4 tweeters, 6 mid-bass) is around 3,200- 3700 Cdn.. and I certainly cannot afford to do this again.. so I want to avoid the major pitfalls now....

I have a Vifa-based pair for use as the rear surrounds

Looking for feedback/suggestions...

Thanks,


Bruce

[sreten]

This is just my personal opinion :

MTM's have larger dispersion issues at crossover than MT's,
due to having 3 interacting drivers as opposed to two.

The larger the mid/bass units the larger the problem as unit
spacing becomes larger.

One way round this is a 2.5way. Ther disadavantage of a
2.5 way is that it forces you to implement full 6dB beffle
step compensation.

With an MTM 2 way the level of baffle step compensation can
be chosen, full, some or none at all (I don't reccomend none).

I'm confused as to the following :

Why do you want more bass if you are using a subwoofer ?
How do you arrive at 4 tweeters and 6 bass units ?
What proven design do you have in mind ?

sreten.

[leadbelly]

Originally posted by HTRookie
.. and I certainly cannot afford to do this again.. so I want to avoid the major pitfalls now

Then don't tackle an original design. Start with something proven. With a budget of $3700 just for drivers and crossovers, you have plenty of choices.

[tiroth]

I just picked up some HM170Z0. (6.5" aerogel) Was a little
disappointed with the top end extension...I would say 3kHz is the absolute maximum which means you should be crossing no higher than high order ~2.5kHz, and that isn't ideal. 8" should be even worse. Hard to find a tweeter that goes that low happily.

All of these aerogels are of course slightly different but based on my measurements of its cousin and the published response, it looks iffy.

[HTRookie]

Thanks for the help...

As was suggested, I will lose the 8" plan, and stick with what has been shown to work time and again ..6.5".. From my end of it, I am considering the following 6.5"/7" drivers:

1. Audax AM170Z2 shielded
2. Focal 6W4311B shielded
3. Scan Speak 18S-8531G00 (7" slit-cone ) shielded

The first two are close in price, while the Scan Speak is $297.88 Cdn each... about 40% more than the other two ..

From what I have read, all of the above are considered good quality drivers... I am not sure of the Scan-Speak is worth the money.. I need 6 (2 each for the front three speakers)..

And no, I just need 3 tweeters, sorry, fumble fingers keyboarding

I am willing to pay for the Scan -Speaks, but am uncertain if this is a wise place to spend the extra money...

Again, I am looking for advice here

Thanks,

Bruce

[sreten]

You said "go with a proven design".

IMO the Focal and especially the Scanspeak are more suited
to critical music listening than HT, i.e. the resulting speakers
would need some serious amplication.

.. so I want to avoid the major pitfalls now....

Without measuring equipment the major pitfall is
not copying a published and measured design.

sreten.

[HTRookie]

I should have clarified..- I truly am a rookie

The speakers will be used for probably 60 % HT, 40 % music-which ranges from primarily classical to the occasional rock n roll/jazz listening session..

The amplifier power part I have not approached yet... I do not listen at very high SPL levels anymore.. I have done the damage to my hearing already, from the foolishness of youth..

From what I read, the Scan-Speak and Focal drivers seem to be considered top quality.. that is the primary reason I considered them..

I cannot say I listen critically for long periods to music-at this point I do not, but having said that, I do not want to limit the quality of the system based on my present usage...

Please keep the comments coming Sreten, I appreciate your help..

Bruce

[sreten]

Try this :

http://www.madisound.com/audaxhometheater.html

get some ideas here :

http://www.partsexpress.com/projects...homeaudio.html

First time around its better go for good rather than the best.

sreten.

[leadbelly]

Originally posted by HTRookie
My budget for the drivers and crossover components(subwoofer, 4 tweeters, 6 mid-bass) is around 3,200- 3700 Cdn..

Originally posted by sreten
First time around its better go for good rather than the best.

Also, you have a pretty good sized budget. If I had this budget, I would not be looking at 5 bookshelf & 1 subwoofer using high end drivers. I would start looking at 5.0 or or 5.2 designs using less pricey drivers. Either 5 full rangers with deep bass and no subwoofer, or stereo subwoofers on the fronts.

[Ap]

I would seriously consider using drivers which are easy to xover - that pretty much rules out a lot of stiff cone drivers.
My pick MTM with Seas P17rex or CB17rcy - check out the Proteus DIY design on the web.
Also look at snippets.org/ldsg for more info.