Large RS MTMWW 3way midrange question.

[Jonniebravo]

I believe this is the first question i've openly asked on the forum,however i've been stopping by to see what projects you guy's have been cooking up. I'm going to build the large RS 3-way towers, but noticed that chris might have had second thoughts about using the RS180's. He mentioned the RS150's may have been a better choice. Your input would be greatly appreciated...Jon

[cjd]

This is/was an issue of "if I had been picking the drivers"

Having designed with the RS180's, I have no hesitations about continuing to recommend them for this design. They're superb.

If I were to sit down to build these from the ground up again, I would still give the RS150 a serious look. But it has always been a game of splitting hairs - you gain some, you lose some, whichever way you go.

Perhaps Brian can comment here since he has built the center channel using the RS150/RS225 that should match up with the WWMTM towers quite well (having heard nothing to the contrary, I hope that supposition is accurate).

C

[JonW]

One related thing I've wondered about...

There are two 3 way RS tower designs in the Missions Accomplished. I've read through both lengthy threads. Many people have made the smaller design by Dennis/Curt/Jon for the RS28a/RS150/RS225. And there is Chris' larger RS28a/RS180/RS270 design built by only a couple people.

How do these two speakers compare?

Perhaps the larger design is "better" in terms of not needing a sub for music? Or not. Just curious. I doubt I'll ever have the time, but I have been thinking about making a dedicated theater room and I'd need new mains. What to make?

[Jonniebravo]

Suppose we're looking at the advantages of using the RS150's, what would they be? The spl between the RS180 and the RS150 is marginal, what i'm looking at is crossing over to the RS28 at a higher freqency. would there be something to gain in terms of the tweeter not having to work at the lower limits of it's freqency response?...Jon

[cjd]

It's not the crossover frequency that's the difference specifically, as much as it is piston size at that frequency.

You would gain about 200Hz, as I would cross the RS150 at ~1800Hz. Not much, but... 1600Hz is quite comfortably in the range the RS28A can function happily. The SPL difference is actually useful, though not required for the design, obviously.

You also gain a very little bit in box size needs.

The RS150 seems to my ear to be slightly less analytical - it definitely has a ligher weight cone.

On the down side, you have a larger disparity on the bottom end both with driver size and effort. You also have much more restricted back-wave as the clearance from the magnet to the cutout is small indeed with the RS150 on a 1.5" or 2" baffle. Box construction might be more complex as full width mid-bass cabinet might be too shallow and have backwave bounce issues.

C

[Jonniebravo]

It's likely i'll build the RS towers identical to yours. Just wanted to know if a change from the RS180 to the RS150 would provide a concise advantage. It appears not, thanks for the info chris...Jon

[wildfire99]

I always considered the MTMWW project as more of a dedicated 2-channel listening system, whereas the more traditional dayton 3-ways were theater-oriented, where you use a sub for the low end.

As far as theater use is concerned, if you're going with a perfectly capable subwoofer anyway, is there a useful gain to be had going with the bigger MTMWW mains over the other Dayton 3-ways (aside from really cool "my woofer is bigger than yours" bragging rights)?

[cjd]

The larger towers will cross happily when sealed at a lower frequency.

C

[ThomasW]

I always considered the MTMWW project as more of a dedicated 2-channel listening system, whereas the more traditional dayton 3-ways were theater-oriented, where you use a sub for the low end.

I would say the opposite is true. The MTMWW has enough midwoofer Vd that it's unstressed by the transients in DVD soundtracks. The TMWW and it small midwoofer lacks the Vd for higher SPL transisents in the soundtracks.

[cjd]

I should probably mention, my long-range HT goals include a set of these... I'll have to build the house for that HT first, however. They also have a dispersion pattern that would work well with multiple rows of seating that is tiered.

They're just not what I want for serious music long-term (dipole).

I'm still trying to get my wife settled on the idea of a 4-sub array in the living room (IB of course) to ease the bass duties and really get me that 8Hz range I want. Got a spot for 'em. Would even put 'em behind a wall-colored grill-cloth so they would blend in pretty well. I'd have to move her diploma though, and possibly a light switch... :B

C

[JonW]

I would say the opposite is true. The MTMWW has enough midwoofer Vd that it's unstressed by the transients in DVD soundtracks. The TMWW and it small midwoofer lacks the Vd for higher SPL transisents in the soundtracks.

OK, then I'll ask (another) ignorant question because I've yet to have anything beyond a 2.1 system...

Isn't most (~80+%) of a movie soundtrack really coming through the center speaker? And the left and right mains and rears are mostly just for ambient sound. So if you have a really good center and a sub to handle the lows, you're good to go. No need for MTMWW's on the left and right. Even MT's for everything but the center is OK. Or not. I've got no experience with watching movies in 5.1 or 7.1. Although I'm considering building a series of speakers for a dedicated theater room in the house. So I've been wondering what type of speakers I should make. People seem to go simple MT's for the rears/surrounds. How about the left and right mains if it's just for movies? Probably not a topic for a DIY forum, I guess.

[JonW]

I should probably mention, my long-range HT goals include a set of these... I'll have to build the house for that HT first, however. They also have a dispersion pattern that would work well with multiple rows of seating that is tiered.

They're just not what I want for serious music long-term (dipole).

By "a set of these" you mean the WWMTM's for HT, correct?

But the WWMTMT's are still lacking for music without a sub, eh? Interesting.

What dipole do you have in mind? I'm thinking about a full 7.1 setup in one room using my current sub. And then a 2 speaker system in another room just for music, without a sub. Not sure what would be best for the 2 channel system- Arvos? Hmmm...

[ThomasW]

Isn't most (~80+%) of a movie soundtrack really coming through the center speaker? And the left and right mains and rears are mostly just for ambient sound.

The center channel is the 'dialog' channel, so that's primarily where the voices come from.

[WillyD]

How about the left and right mains if it's just for movies? Probably not a topic for a DIY forum, I guess.

Thats how I use mine at the moment, but make no mistake, the L/R channels are still very important in a HT setup. I have The Fifth Element playing now, and I notice plenty of effects/gunfire/etc coming through the left and right channels, but yes, the center is utilized to a great extent.

If I was starting from scratch, I'd at least go with Natalie P or Modula MTMs for the L/R, and the appropriate WMTW center whether it be the one that Evil Twin is currently designing or the popular ones using the RS150.

[Evil Twin]

I believe this is the first question i've openly asked on the forum,however i've been stopping by to see what projects you guy's have been cooking up. I'm going to build the large RS 3-way towers, but noticed that chris might have had second thoughts about using the RS180's. He mentioned the RS150's may have been a better choice. Your input would be greatly appreciated...Jon

If contemplating something like this from scratch, the Peerless 830883 is one I would consider carefully for it's very low midrange distortion- 3rd harmonic being 6-10 dB lower up to 2 kHz.






But it is arguable whether that would be a point to consider worth modifying an existing design.


A new MT with this driver and a waveguide loaded tweeter might be an interesting idea to consider- time permitting.

[soho54]

100% opinion follows. :B

Isn't most (~80+%) of a movie soundtrack really coming through the center speaker? And the left and right mains and rears are mostly just for ambient sound.

The left and right mains are very important in HT. The center gets most (90%) of the dialogue and some effect sounds like gun fire and explosions, but it is mostly for added effect to "center" the sounds as they are also mirrored in the L&R as well. Most all of the movies dynamic soundtrack comes from the L&R, so they have to be able to play cleanly. An MTM center with an 80hz highpass is my bass line though. Keep any MT's out back.

How about the left and right mains if it's just for movies?

I have played with different configurations and to me you want the most capable speakers on the L&R, if you can't use the same speakers all around. I have switched my old setup around and used an MTM as the center and MT's as the L&R, and it didn't work. LOTR's soundtrack killed the MT's at anything greater than "irritated wife" volumes. I could never get the bass management to mesh right without severely limiting the center as well, which kinda defeated the purpose.

People seem to go simple MT's for the rears/surrounds.

Surrounds to me are the only ambient channels. With that said the bigger the better still, because you never know when they are going to throw a helicopter or something else crazy back there. MT's are fine as long as your crossover is right. With 5.1 I would say MTM rears, but with 7.1 the MT's may be all that is needed.

[Jonniebravo]

If contemplating something like this from scratch, the Peerless 830883 is one I would consider carefully for it's very low midrange distortion- 3rd harmonic being 6-10 dB lower up to 2 kHz.






But it is arguable whether that would be a point to consider worth modifying an existing design.


A new MT with this driver and a waveguide loaded tweeter might be an interesting idea to consider- time permitting.

At this point i'm committed to the RS drivers, i have all the woofers from 5" to 10". My goal is to complete a large HT system over the winter. I've finished my 15'' downfiring sub and i'll post photos as soon as i figure out how format the proper size on to the forum. I was under the impression that the RS MTMWW would be great for HT and 2 channel music...Jon

[Brian Bunge]

I still much prefer using a sub with the MTMWW's even for music. I haven't finished the center yet but should have it done shortly. I've now got all the parts I need and just need to build the crossover and do final assembly.

[Jonniebravo]

Brian, what RS drivers are you using in your center channel design...Jon

[JonW]

I still much prefer using a sub with the MTMWW's even for music. I haven't finished the center yet but should have it done shortly. I've now got all the parts I need and just need to build the crossover and do final assembly.

Really? OK, well then forget about my plans for making those to have a 2 channel, no sub music setup.

I guess my search for some DIY speakers that don’t need a sub for music continues. (*cough* finish the Arvos *cough cough*)

Thats how I use mine at the moment, but make no mistake, the L/R channels are still very important in a HT setup. I have The Fifth Element playing now, and I notice plenty of effects/gunfire/etc coming through the left and right channels, but yes, the center is utilized to a great extent.

If I was starting from scratch, I'd at least go with Natalie P or Modula MTMs for the L/R, and the appropriate WMTW center whether it be the one that Evil Twin is currently designing or the popular ones using the RS150.

Great info- thanks.

100% opinion follows. :B The left and right mains are very important in HT. The center gets most (90%) of the dialogue and some effect sounds like gun fire and explosions, but it is mostly for added effect to "center" the sounds as they are also mirrored in the L&R as well. Most all of the movies dynamic soundtrack comes from the L&R, so they have to be able to play cleanly. An MTM center with an 80hz highpass is my bass line though. Keep any MT's out back.

I have played with different configurations and to me you want the most capable speakers on the L&R, if you can't use the same speakers all around. I have switched my old setup around and used an MTM as the center and MT's as the L&R, and it didn't work. LOTR's soundtrack killed the MT's at anything greater than "irritated wife" volumes. I could never get the bass management to mesh right without severely limiting the center as well, which kinda defeated the purpose.

Surrounds to me are the only ambient channels. With that said the bigger the better still, because you never know when they are going to throw a helicopter or something else crazy back there. MT's are fine as long as your crossover is right. With 5.1 I would say MTM rears, but with 7.1 the MT's may be all that is needed.

Very good to know- thanks. I guess I’ll figure all this out for myself, soon, when I have my 5.1 system complete. I didn’t realize so much came from the left and right fronts during amovie.

[Brian Bunge]

My center uses the same drivers as everyone else's (assuming all Dayton drivers): dual RS225's, RS150 and RS28a.

Jon,

You could build the dual RS225 towers ported and not need a sub. Chris and I specifically designed the MTMWW with the dual 270's sealed because my plan was to use a big sub from the beginning. You could build them ported but they'd be even bigger than they are now. Or a re-design using active RS 10" sub per side could give you a full range tower.

[Jonniebravo]

Brian, I've built a large sub with a 15" driver and 1000 watt amp that sounds great, would'nt a sub of that size and output be enough? I could add the RS10" sub's, but i already have 4 of the RS270's and i like the design of the Large 3-ways. I could build a larger version, ported if i needed to,but what you guy's have built is pretty nice. One question, could the RS 3way cabinet be built 3 to 4 inches taller and 3 to 4 inches less in depth if it remained a sealed enclosure?...Jon

[Brian Bunge]

Yes, a sub of that size should work pretty well. I'm only using a measly little 10" sub and 300W amp right now. It adds enough bottom end for most of my music listening, but is sorely lacking in movies.

As far as the cabinet dimensions, as long as you keep the same internal volume and keep the baffle width the same you should be ok. The only other real issue is whether or not that would put your tweeter too high above ear level.

[Jonniebravo]

I've sent you some pictures Brian, to give you an Idea of what I'd like to attempt with the MTMWW 's you and Chris designed. Let my know If you think It would be possible...Jon

[Brian Bunge]

Jon,

I got your picks. You could definitely do the baseplate similar to your subwoofer, but I don't think it would look all that great. What I did was place a piece of 1/4" pegboard that was several inches smaller in width and length than the bottom of the enclosure on the top of my 1.5" thick baseplate. That way there is a relief between the cabinet and baseplate. Here's a picture of the cabinets before the drivers and crossovers were installed to give you an idea of what I'm talking about.

http://www.radhometheater.com/photos/3way_cabinet_black_baffle_3.jpg

[Jonniebravo]

Brian, I see what you mean. I didn't notice that before...Jon

[mmoeller]

If contemplating something like this from scratch, the Peerless 830883 is one I would consider carefully for it's very low midrange distortion- 3rd harmonic being 6-10 dB lower up to 2 kHz.






But it is arguable whether that would be a point to consider worth modifying an existing design.


A new MT with this driver and a waveguide loaded tweeter might be an interesting idea to consider- time permitting.

I'm wondering how the HDS version compairs with the standard Nomex cone 6.5". 830875.

http://www.madisound.com/cgi-bin/index.cgi?cart_id=1715995.4496&pid=1958

I'm very interested in a Peerless design with a waveguide tweeter. I've listened to some Revel Performas and really enjoyed their waveguide tweeter. They were however 3-way tower F52. Which included a 5.25 for mid and 3 6.5s for the low end. I was also wondering how far the 6.5s would extend in that type of setup?

[Jonniebravo]

Brian, when you first started your thread for the RS 3way's, there was talk of maybe bi-amping for the RS270's. Perhaps you were thinking of sub amp's for the woofers ? I'm starting to cut wood this weekend and noticed that PE has subwoofer plate amp's on sale, so I thought I'd ask a few more questions before I began...Jon

[agrippa]

I hate to make this more of an issue, but I like the RS line more for the woofers.
The mids are great for the money but you may want to look at some nicer mids like the one EVIL TWIN pointed out. They are nice. In fact they are on my really short list for my refrence speakers I am planning.
It depends on your budget. Personally I am looking at a design like a MTMWW or a TMWW. Right now I am sitting on 8 RS225's and they want to be listened to.

[Brian Bunge]

I wasn't really thinking sub amps because I wasn't crossing over around 80-100Hz. I'm not sure how well a sub amp would work up around 200-300Hz (assuming you can defeat the low pass filter). I was thinking more of an outboard 2 channel amp dedicated to the woofers.