# MTM or WMTW with large sub?



## tjambro (Jan 16, 2007)

Hi, I'm fairly new to DIY and have a question for the pros. I'm just finishing a SS dual RL-p18 sub for my dedicated theater room:

http://www.hometheatershack.com/forums/soundsplinter/3916-dual-rl-p18-llt-begun.html

I have the subs behind and under my acoustically transparent screen/fake wall and now my Def Tech LCRs are higher than I want them to be. I'm using this as an excuse to try my hand at DIY speakers. :devil: 

The sub is being crossed over at 90Hz from my Yammy receiver. Whatever I build for the L/C/R's I would like them to all be the same. Appearance is not an issue because all 3 will be behind the screen. I have 1" insulation on the walls behind the screen and there is only about 20" from the back wall to the screen. Large towers are out due to height.

I am seriously considering 3 RS WMTW speakers all placed horizontally as they are intended to be. Would I be better off with 3 Modula MTM's all placed vertically as they are designed since they have two midrange drivers per speaker instead of the one in the WMTW configuration? Would the MTM's be strong enough from 90Hz up to mate with my sub and play at near reference levels?

-Tom A.


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## JCD (Apr 20, 2006)

I haven't had a listen to either of those particular speakers yet.. I'd like to some day though.

Anyway, I thought I'd see if you were choosing between those two or if you would consider other designs? And if so, what would your budget be?


JCD


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## tjambro (Jan 16, 2007)

JCD said:


> Anyway, I thought I'd see if you were choosing between those two or if you would consider other designs? And if so, what would your budget be?


I would be willing to consider other designs as long as they are no taller than about 24 inches and no deeper than about 15". I would like to spend $400 or less per speaker but if the speaker is phenomenally better I could go about $500 a piece.

Do you have anything in mind?

-Tom A.


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## JCD (Apr 20, 2006)

I do have something in mind.. 

I've heard nothing but praises for the Odin kits by Seas. It's an MTM design by Joe D'Appolito. You can get the entire kit (without box) at Zalytron for just under $500/speaker. And, its 22" tall and 14.25" deep.

Now, I have to admin that I've not heard any of the referenced kits in this thread, but the one person I know who has unequivocally recommends the Odin (or Thor) kits over pretty much anything out there.

JCD


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## Guest (May 30, 2007)

I know I am new and don't really want to butt into your thread but I am in the process of building a modified Modula design MTM with a much simpler network that is costing me about 125$ per speaker. I have built my own cabinets-so if you buy the PE cabinets figure 225 a piece but these seem promising I have been listening to one to demo and decide how my crossover network is working. I will post the build info here in a few days the project should be all but in the finishing phase today still(undecided how to finish). If you want I can make a post showing what I have so far the cross over is not an 8th order CE but it does get the breakup of the Rs180s down alomost 40db so I feel to my ears so far it's inaudible and the response is just as flat.


Bri


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## tjambro (Jan 16, 2007)

Brill said:


> I know I am new and don't really want to butt into your thread but I am in the process of building a modified Modula design MTM with a much simpler network that is costing me about 125$ per speaker...Bri


Bri, no butting in at all, I appreciate your time. Feel free to post whatever you would like, that's what these forums are for! :T

I'm not so sure I will build the WMTW after all. I'm now leaning to the Natalie P's which as you probably know are a variant of the Modula MTM. The crossover is a bit cheaper. Since I have the large subs, I might be better off with the MTM configuration, at least that is what I've been told and I must say it makes sense to this newbie. 

-Tom A.


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## Guest (May 31, 2007)

Well you may be interested in waiting a bit longer. Not trying to cut other designs down but like I said my crossover version of the RS180/H1212 cost about 125 each and I will post the info as soon as I can the Crossover, the curves -my listening impressions. Like I said earlier I mocked up a tester and it sounded very clean I couldn't hear any of the 2 and 5KHZ breakup the RS180 are known for. But on the other hand the Nat p's are certainly a proven performer

Bri


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## tjambro (Jan 16, 2007)

Brill said:


> Well you may be interested in waiting a bit longer. Not trying to cut other designs down but like I said my crossover version of the RS180/H1212 cost about 125 each and I will post the info as soon as I can the Crossover, the curves -my listening impressions. Like I said earlier I mocked up a tester and it sounded very clean I couldn't hear any of the 2 and 5KHZ breakup the RS180 are known for. But on the other hand the Nat p's are certainly a proven performer
> 
> Bri


Ok, you still have my attention. :T I look forward to seeing your design and thoughts.

Will your design have BSC? I'm still not sure if I need BSC or not? From the front baffle of my speakers to the wall behind the speaker will be about 20". I've read that BSC is needed when speakers are 1.5-2 feet from the wall and that xo networks without BSC were preferred when the speakers were mounted on wall or in wall. What if the back of the speaker box is 4-8 inches off the wall?

-Tom A.


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## tjambro (Jan 16, 2007)

JCD said:


> Now, I have to admin that I've not heard any of the referenced kits in this thread, but the one person I know who has unequivocally recommends the Odin (or Thor) kits over pretty much anything out there.
> 
> JCD


Are you saying that this person has heard the Modula MTM or Nat P and prefers the Odin or that he/she prefers the Odin over anything he/she has heard? Boy, is picking speakers hard. :bigsmile:

-Tom A.


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## JCD (Apr 20, 2006)

tjambro said:


> Are you saying that this person has heard the Modula MTM or Nat P and prefers the Odin or that he/she prefers the Odin over anything he/she has heard? Boy, is picking speakers hard. :bigsmile:
> 
> -Tom A.


Sorry for the delay.. but yeah, he thought they were the best kit out there. They cost more than the Modula's and Nat P's, but *HE *thought they were worth it. He also thought the upgraded crossover's were worth it too (I know they have them at Madisound, I'm not sure about Zalytron). 

I saw somewhere around here that either the Odin or the Thor kit could be improved upon with a different enclosure -- I can't recall where I saw that, but there was a thread on another forum that went through all the motions of what was entailed. 

And yeah, picking speakers is hard -- and picking a kit is even harder! But that's why it's so fun! :bigsmile:

JCD


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## Darren (Apr 20, 2006)

I'm considering the Modula and/or Natalie P design as well to replace my GR-Research AV2's. My current mains are MTM design but the size of them is a bit small for my growing need. They are great speakers but something I've found is that I need more mid-bass punch. My IB subwoofer is crossed over at 60Hz and sometimes 80Hz depending on my mood. Of course the mid-bass is in the 80Hz - 150Hz range or there about. Be sure and pay attention to your mid-bass needs/desires. That is VERY important to me now in order to blend better with my subwoofer.

I'm still trying to determine if the Modula or Natalie P will have sufficient mid-bass punch to match up with my IB for HT and music. It is all subjective of course. An important thing for me as well is designs WITHOUT BSC as my speakers will be built into the walls for WAF as I upgrade.


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## SteveCallas (Apr 29, 2006)

Your dual RL-p18 subs give you a whole **** of a lot of juice on hand and the 90hz crossover essentially eliminates the need to have mains that extend very deep. Taking that into consideration, I'd try to put that full 24" height limit to good use with something like a TMMM using three 6" midrange drivers or, if you can find a suitable driver, a TMM using two 8" midwoofers. 

Something like Ascend 340s, which use dual 6.5" drivers, just couldn't hang with a dual RL-p15 LLT subwoofer at spirited levels, so.....


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## tjambro (Jan 16, 2007)

Darren said:


> I'm still trying to determine if the Modula or Natalie P will have sufficient mid-bass punch to match up with my IB for HT and music. It is all subjective of course. An important thing for me as well is designs WITHOUT BSC as my speakers will be built into the walls for WAF as I upgrade.


You and Steve both bring up a good point about having enough mid-bass...thanks guys! In addition to the Nat P's I am also considering the WMTW center channel mentioned on that popular home theater DIY speaker site. It's a 3-way design using two Dayton RS 8" drivers for bass/midbass, one 6" midrange driver and one tweeter. I would build 3 center speakers in this configuration for my LCR's all behind my perfed screen. I'm just not sure if this would be better than a MTM design or not?

I understand that non-BSC designs make sense for in-walls, but what about speakers in which the front baffle is about 18" from the wall? What if the back of the speaker is only 4-6" from the wall? I will probably need a non-BSC design for surrounds, assuming I eventually build them....I'm sure I will. :yes:

-Tom A.


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## SteveCallas (Apr 29, 2006)

At what frequency would the mid in that design be crossed to the woofers?


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## tjambro (Jan 16, 2007)

SteveCallas said:


> At what frequency would the mid in that design be crossed to the woofers?


If I'm reading the FR plot below correctly, it looks like everything below about 425Hz will go to the woofers. What do you think?









Here's another crossover for the same design:









-Tom A.


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## SteveCallas (Apr 29, 2006)

Ok, that sounds good - high enough to keep the demand on the midrange pretty low. The only concern I would have now is that a speaker designed to be used as a center (with the midrange next to the tweeter with a woofer on top an dbottom) is that the imaging and soundstage may not be as good as it would with a more traditional main speaker design.


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## tjambro (Jan 16, 2007)

SteveCallas said:


> Ok, that sounds good - high enough to keep the demand on the midrange pretty low. The only concern I would have now is that a speaker designed to be used as a center (with the midrange next to the tweeter with a woofer on top an dbottom) is that the imaging and soundstage may not be as good as it would with a more traditional main speaker design.


Actually I would place all 3 horizontally as they are designed to be placed. This will put the two woofers on the outside with the midrange driver in the middle. The tweeter would be above the mid.

Here's a schematic:









My other concern is that each enclosure is 26" wide. Add the 3 and that comes out to 6.5'. They would be behind my 10'5 wide perfed screen. I think it may be ok because the mid/tweet's (from each box) would be further apart than the woofers.

What do you think?

-Tom A.


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## Guest (Jul 17, 2007)

Hey Tom I haven't been on in awhile for various reasons but I do have a pair of the above speakers completed well albeit without veneer I would like to start a thread about the build if others are interested.

Bri


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## 1Michael (Nov 2, 2006)

Yes start a new thread with your build on that center because I am going to build that very one. Also for my 1/2 cent worth I'm going to build 2 NatP Towers for the surrounds, and 2 RS MTMWW towers that Brian Bunge built for the mains. They are similar to the RS WWMT at htguide. I also have the RLP15 Sonosub and a RLP18 sealed sub and this should complete my home theater system for now.
I have heard alot of good things about the NatP's over there but ultimately you will have to take the plunge and try it. If you dont like it try again


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## Guest (Jul 19, 2007)

buggers said:


> Yes start a new thread with your build on that center because I am going to build that very one. Also for my 1/2 cent worth I'm going to build 2 NatP Towers for the surrounds, and 2 RS MTMWW towers that Brian Bunge built for the mains. They are similar to the RS WWMT at htguide. I also have the RLP15 Sonosub and a RLP18 sealed sub and this should complete my home theater system for now.
> I have heard alot of good things about the NatP's over there but ultimately you will have to take the plunge and try it. If you dont like it try again


I think you better reread the thread. I built a lower budget version of the Modula MTM's not  a center


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## tjambro (Jan 16, 2007)

Brill said:


> Hey Tom I haven't been on in awhile for various reasons but I do have a pair of the above speakers completed well albeit without veneer I would like to start a thread about the build if others are interested.
> 
> Bri


Bri,

I'm sure I'm not the only one interested in your project, so if you can DO start another thread with pictures. :bigsmile:

I haven't decided what to build yet. Every time I think I found "the one" something else pops up. What I have now is not exactly bad, so I am going to take my time.

-Tom A.


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## Guest (Jul 21, 2007)

Hey Tom

Thanks for the reply. I am going to start a thread in a few days. I have been listening to them for a few weeks and for Theatre these things are awsome., however that being said in two channel I am having issue yet but I will discuss that more. :bigsmile:

Blessings 

Brian


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## Guest (Jul 29, 2007)

Hi all, thought l'd add to this post as l have seas thors and odins for my 5.1 ht , they are a good sounding speaker and l run them with a 4 x 18'' ava sub and as a whole it's pretty impressive, that being said l'm toying with the idea of maybe running bass bins to supplement the upper bass regions and cross the ib over at a lower point.......has anyone done this at all? , l was thinking along the lines of it looking and working like a wattpuppy etc........this would be a long term project as funds are non existent atm.

Tom, you can't go wrong really with most of the better qaulity kits out there.....l originally built the audax ht kits and was pretty impressed with them ( 4 mtm's and wmtw centre ) , but they got slightly damaged in a housefire we had a couple of yrs ago , so l got the seas's as replacements and am going to repare the audaxs later this year.
l found the seas's like a bit power and they sound their best running around reference levels , l have to be careful as it's easy to run them at higher levels without realising the actual db level at the time, anyway enuff said hope this helps a bit mate.....also if anyone has done added bass modules to mtm's it'd be great to hear from you...
cheers Ken


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## Doug Plumb (Mar 16, 2007)

I want to build a pair of high end speakers myself soon. The reason I think I can do better than store bought is that I can put giant radii around the front edges - 1/4 of Xover freq wavelength. Although the effect of diffraction does not show up clearly in frequency response measurements I know its effect is very degrading.

That aside I would use an electronic crossover because then I could use 8 th order Xover filters. 8th order Xover filters are better than lower order filters and very easy to implement.

I wouldn't expect to be able to implement a second order passive Xover well, its lower order makes it too difficult. A higher order passive Xover becomes impractical and I don't know of a passive 8th order Xover.


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## digital desire (Dec 17, 2006)

Maybe "It's a sound only mother can love". But I will say if you build the WWMT's, I would think you would be hard pressed to find any faults with them. They really are GREAT speakers.


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## Sonnie (Apr 11, 2006)

Hi dd... welcome to the Shack!

Did you build that? Nice!


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