Surround choices

[kgveteran]

First, where I'm going.I'm looking for three surround speakers.I have room for 6.1 which I am using now.

My subs are (4)Adire Tumults sealed, powered by QSC 1450's bridged each.My mains are three RS centers all three stand horizontal.Soon to be powered by three Outlaw Audio M-200's each. I have done alot of research to get to this point.Mt front stage is very strong and clean and clear.It extends down to 10hz and up to well over 105db, to give me the headroom at normal 85-90db listening.Thanks to you guys.

I need three surrounds that won't give out under pressure.I want to build these once and be done...for a while.I XO @ 100hz. I was looking at the WT RS180/RS28a sealed . The tweeter is fine ,but the 180 I feel will breakup under high SPL's (Or not).I was also thinking the WTW RS150/RS28a/RS150 sealed.I built that one for my cabinet guy and he loves it.I need to round out this system just shy of three more RC Centers .

My one concern is the XO point for the rear surrounds.I would rather use 80hz due to the distance from front stage sub to rear speakers.The 100hz point for the mains is fine as the subs are upfront and center and blend quite well.

This project will take the remainder of the winter so I have time.Cabinets,XO's
and an amp to power them.I like the three channel B&K 1430.It's about 125 per channel.Your thoughts.

KG

[crackyflipside]

Have you thought about the MT's?

I don't know of any WT???

[BigJim_inFLA]

I'm running Modula MT's as my surrounds with 125W per into them and crossed at 80. They sound great, probably deserve better than surround duty. I did run them in place of my mains when I first finished building them and they do have a good bit of bass, enough that you could probably cross them even lower if you wanted to, and they do play loud quite cleanly. I haven't done any measurements as to how loud and really can't now that I'm back in an apartment with neighbors. I'm running the RS 3way center and my mains are Klipsch Chorus II's until I finish my RS 3 way TMWW's. I think they really hold there own with the much bigger and more efficient front end.

[joecarrow]

I've had the MTs up past -20 with my Panasonic SA-XR55, and the only time the woofers have shown me any signs of distress is during movies with large explosions. I always leave them in "large" mode, and I'm not sure if that mixes the LFE to the front channels or not- but during the largest explosion in Cold Mountain's civil war scenes it got really ugly.

I'd imagine that with an active 100 hz highpass, you'd be able to seriously push these things. Like Jim, I'm in an apartment so my experience with your level of SPL is limited. Of course, you can play around with some simulations and either raise the box tuning or go for a sealed alignment to limit excursion.

[cobbpa]

With your concern for clarity at high levels, my first thoughts were Mark K's RS225/RS228A MT for its 8" woofer. Second was Zaph's ZD5 he recently put up. The woofer is smaller and less efficient, but with that power I'd expect it to perform well.
I'll add in that I have not heard either of these designs, only read through their creation process. Also, my typical disclaimer that I'm not extremely knowledgeable..but it seems like they may be worth giving a look for what you want. The ZD5 is maybe expensive for surround duty, but that's obviously up to the person building them.

[WillyD]

I'll just say that the Modula MT, like it's larger brethren, is very capable of high output while maintaining low-distortion....clean, as they say. No, it isn't as capable as the MTMs or your 3-ways, but very-very capable nonetheless.

I also have an XR55 like JoeCarrow, and I keep mine highpassed at 80Hz, and they have never once given me trouble during movies, and they are my mains. :T

[chasw98]

KG:
I have to chime in here and recommend the M/T's. You can build them with the same tweeeter you are using in your mains so that you get a similar signature from all around the system. I am driving mine (4 in 7.1 configuration) with 600 watts each and they love the power. OTOH, they are being used as surround but I still have never seen the clip lights come on or heard any audible distortion even when running in 7 channel stereo. They are an amazing speaker.

[dawaro]

If you are really concerned about the woofer in the MT why not do the Natalie P MTM? With the xovers being comparable the only difference in cost is really just the second woofer.

Or you could build three more of the WMTW's. After all if you are going to go big, go BIG.

I used a sealed version of the MT as a surround and never had any issues. They were driven with a 200 watts and never seemed distressed at all.

[cjd]

I think you can do 80Hz happily with the RS150 MTM's (sealed - ported for sure) - you may get a bit of a dip in response through the crossover region, but it won't be huge, and for surrounds it also won't be important.

C

[kgveteran]

This all came to me while doing the finishing touches on my friends system.We watched "Flight of the Phoenix".His mains did ok,the subs were great, but the surrounds fell apart.Now they are whimpy inceiling surrounds, never meant to handle that type of signal.It did remind me that the rears are full range (rolled off of course).

The last thing I want to do is create rear surrounds that can't handle the 100hz or 80hz signal at their XO point.I'mm go over the speakers mentioned and read up on them.Thanx for your attention.

My plan is to purchase a three channel amp ot just a stereo amp like my favorite Adcom 555mkII.Not sure about the rear center for now.

KG

[kgveteran]

Here is another option that I built for my cabinet guy.It was so damn musical.

http://www.eldamar.net/audio/RS150MTM/

[cjd]

that's the MTM I was referring to, since it's the one I designed.

Helluva compliment too! Thanks!

You can always use 'em as background-music speakers in your bathroom if it doesn't work out.

[kgveteran]

Have you thought about the MT's?

I don't know of any WT???

I think I meant MT or MTM.

[kgveteran]

that's the MTM I was referring to, since it's the one I designed.

Helluva compliment too! Thanks!

You can always use 'em as background-music speakers in your bathroom if it doesn't work out.

Doing a sealed pair would be fine as I don't have any need for the lowend.

[cjd]

Doing a sealed pair would be fine as I don't have any need for the lowend.

bah, just put a sub in the bathroom :P

I do think they would work - you'll hit the limits of XMax at ~100W into them (about 110dB I think) given an 80Hz 2nd order crossover added to combine for a 4th order overall. And there is XMech beyond that.

Of course, you actually get pretty similar results with a single RS180, though it takes 120W to hit 108dB which should get you XMax ~80Hz with the same conditions. Slightly smaller box (10L vs 13L). The 180's have longer throw that mostly (but not quite) makes up for the sensitivity difference allowing similar maximum SPL. Takes a heftier amp to drive the 180's this far too since it's into 120W into 8ohm vs 100W into 4ohm.

C

[kgveteran]

I've become very sensitive to distortion these days.Either speakers breaking up or amps clipping, its alway nice to get back home and listen to some of my fav scenes.

Seems I don't listen as loud as i though.My trusty ratshack meter was peaking out at about 80-85db with the Pod race scene in Starwars and it was very comfortable.Having +20db of headroom would be perfect if my 80db is normal listening.

For music it would be nice to have matching 28a's all around also.

[crackyflipside]

Assuming the same drivers, would an MTM perform better as a surround channel than an MT?

[---k---]

I don't think a MTM would be a good surround because of a MTM's dispersion patterns. I believe that they are typically pretty narrow. Not exactly what you would want for movie surrounds. 5-channel music may be a better story.

Hopefully Thomas, Jon, or Chris will chime in and clarify.

[kgveteran]

Would those characteristics be affected by a very short distance as well.My surrounds are about 5' each from my head, or the head of each person sitting on either end of my sofa.Interesting.

Cracky,
Is this what you were thinking of with your post ?


KG

[crackyflipside]

Would those characteristics be affected by a very short distance as well.My surrounds are about 5' each from my head, or the head of each person sitting on either end of my sofa.Interesting.

Cracky,
Is this what you were thinking of with your post ?


KG

Yeah, I have heard about dispersion issues with the NatP MTM's, and was just wondering in general if MTM offer more or less dispersion than an MT.

I had a talk with chasw98 about surrounds a few days ago. I was contemplating like a dipole or bipole surrounds because it creates a very wide dispersion, but then he brought up the idea of being able to hear the direction of sounds and maybe a super-wide dispersion (like having all the surrounds as dipole/bipoles) would smear the effect of perceiving a sound directly behind you or to your sides.

He guestimated that with today's technology and future technology of multi-channel audio, we won't need to use dipoles/bipoles because the audio guys that mix the surround channels will encode them correctly and we wouldn't need a dipole/bipole surround to fix their shortcomings of audio mixing.

-Chris B

[cjd]

it's not specifically more or less dispersion, it's simply different when talking MTM vs TM

The biggest thing to remember with an MTM is that it has limited off-axis response along the axis. In the case of my MTM it's probably 20 to 25 degrees off-axis either way before response really starts to get wonky.

A TM doesn't have as the suck-out due to wavelength interference between the two mid-woofers, but it still has tweeter off-axis rolloff and timing changes between the tweeter and mid.

C

[Dennis H]

About the very short distance, that's a good thing when you're looking at SPL capability of the different designs. Cut the distance in half, gain 6dB. I'm guessing a single RS180 or two RS150 would match SPL pretty well with the 3-way mains, considering that the surrounds don't need to play as loud as the mains.

About the dispersion, Chris nailed it. With a typical MTM mounted vertically, you can get way off axis side-to-side but not very far off axis standing up. KG, I don't know how your seating is. If it's a single row with side speakers directly to the side and the rear straight back you could still make MTM surrounds work. Mount the side speakers tipped on their side -- wide box, not very tall. They would have good dispersion up and down to catch all the seats. Mount the rear speaker the normal way, tall box, not very wide, aimed at head level. It would have good dispersion side to side to catch all the seats.

PS, why only one rear speaker? Everybody seems to be using two.

[kgveteran]

About the very short distance, that's a good thing when you're looking at SPL capability of the different designs. Cut the distance in half, gain 6dB. I'm guessing a single RS180 or two RS150 would match SPL pretty well with the 3-way mains, considering that the surrounds don't need to play as loud as the mains.

About the dispersion, Chris nailed it. With a typical MTM mounted vertically, you can get way off axis side-to-side but not very far off axis standing up. KG, I don't know how your seating is. If it's a single row with side speakers directly to the side and the rear straight back you could still make MTM surrounds work. Mount the side speakers tipped on their side -- wide box, not very tall. They would have good dispersion up and down to catch all the seats. Mount the rear speaker the normal way, tall box, not very wide, aimed at head level. It would have good dispersion side to side to catch all the seats.

PS, why only one rear speaker? Everybody seems to be using two.

Hey Dennis,
Thanx for the post.I am using one rear surround with very good results.Really no need to change.

The room is 13.5W x 15.5L with 9' ceilings. The sofa is about 10' from the front wall.The sides are really about 2' from the rear wall on small shelves,3.5' off the ground.The shelf is the footprint of the speaker.So they're really not rears or sides.The back center is in the back and centered.


KG

[jonathanb3478]

With your concern for clarity at high levels, my first thoughts were Mark K's RS225/RS228A MT for its 8" woofer.

...

I'll add in that I have not heard either of these designs, only read through their creation process.

I have heard Mark K's RS225/RS28a MT. He had it at the Northern CA DIY meet. It was in the .75 cuft (largest) PE enclosure. If you have room for something that size, I think they would be dynamic enough for you.

The meet was in a large church's main worship hall, so it was played at a pretty high level for it to be as loud as it was at my listening position, >25ft away. I believe it acquitted itself well in a venue of that size. It also sounded great. My favorite of the meet.

[kgveteran]

I'll take a look at what looks like a ton of great detail work.The comparisons of the other drivers shows how good those RS drivers are,especially for the cost.

I did a quick read throught, but what was the final impedence of the 225/28a.

While music integrity is important, I seem to be more sensitive to distortion than acoustical signatures.

Thanx for all the input.

The PE .75 cabinets are 63.00 each on special.Looks like a winner.I'll worry about the third once I get these built.Too many changes at once with buying amps and selling amps....lions and tigers and bears oh my :rofl:

[kgveteran]

Looks like the XO's are about 100.00 each.The 28a's are 32.00 each (special) and the 225's are 43.00 each.

I was thinking about a XO mod because they wil be mounted close to the side wall, but I have a two channel PEQ that I can use for them.

[cjd]

Yeah, Mark's TM's would technically need a BSC tweak for near-wall which would also bump up sensitivity.

C

[kgveteran]

Yeah, Mark's TM's would technically need a BSC tweak for near-wall which would also bump up sensitivity.

C

Once in place, I could run some sweeps.Better to keep the XO's as designed, I could always use them elsewhere if needed.

[kgveteran]

Looks like Mrs. KG couldn't figure out what to buy me for Christmas.She asked the all mighty question...."Do you need anything for your videoroom" ?

On their way are two RS28a's and two RS225's...looks like my project will be underway sooner than I thought....oh, free shipping too .

Thanx Mrs. KG !

[omarmipi]

kgveteran, do you know the approximate weight of Mark's Dayton MTs (Drivers, enclosure, crossover)? I have a pair of Dayton RS225S that I would like to try in the MTs but my surround speaker bracket only holds a max of 25lbs.

[kgveteran]

kgveteran, do you know the approximate weight of Mark's Dayton MTs (Drivers, enclosure, crossover)? I have a pair of Dayton RS225S that I would like to try in the MTs but my surround speaker bracket only holds a max of 25lbs.

The PE cabinets are 24lbs each.The RS225 is 8lbs and the tweeter is 2lbs.Without the back plate and crossover it's about 35lbs already.I'd guess it would be about 37lbs assembled