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Capable surrounds with placement flexibility to match up with new front build

post #1 of 23
Thread Starter 
Well seeing as the snowball in already rolling down the hill, I might as well not try and stop it. biggrin.gif

I have my order in for my TD15's/4550/Seos 12 (hopefully 15 but we'll see), for my front build. I am currently running Axiom QS8's for my side surrounds which I have been very happy with. One of the things I like the most about them is their quadpolar design that allows some placement flexibility while still sounding very good. I'm running two rows of seating and have my side surrounds placed about 3' behind 1st row and 2' in front of the second. I can't go with 2 rows of side surrounds, so the rear seating isn't going to be optimal (but I don't sit there so......... smile.gif ) That being said, they do a good job of immersing both the front and rear row.

I don't want to give up the immersive factor the QS8's provide. Everyone likes the SEOS as they are more direct than dome tweeters. Wouldn't this be detrimental when using as side surrounds? Now if I had one row of seating I can see wanting a direct radiating speaker, but when trying to cover a wider range, aren't bi/quad polar designs more effective?

I'm debating on a TD10m with SEOS12/4550 to match the mains. The kicker is; I need to keep the box depth to around 6" as I want as much room as possible with my narrower room. I was thinking about an angled box mounted just underneath my sofit (8" deep at the top and 4 or 5" deep at the bottom) pointed down towards the listening position. I'm just concerned the 12 isn't going to have a wide enough pattern???

Thoughts?
post #2 of 23
i would vote for more diffuse sound from surrounds, but that is one opinion.

there were several posts about this in chop's build thread just a few days ago.

http://www.avsforum.com/t/1457166/s-e-o-s-r-mega-build

i forget which page the surround discussion begins on.
post #3 of 23
Thread Starter 
I'm with you, which I don't think the SEOS is capable of; unless going with a crazy 24" wide Chop version. biggrin.gif

So if we both agree with more diffused surrounds (regardless of right or wrong, as that's what I prefer), what combination would you recommend building that would match up well, while still retaining that "quadpolar" approach?

Maybe I should just gut my QS8's and replace the existing drivers with a pair of TD6's (2 per surround) . smile.gif I'd just need to find some tweeters that would match up well.
post #4 of 23
Why not just copy the design but use other drivers? It's not an entirely radical design.
post #5 of 23
I agree with Scott, just copy your QS8's and be done with it.
post #6 of 23
I have been looking into attempting to build a pair of bipolar or dipolar surrounds for my theater setup, as I am running bipolar mains right now. I absolutely love the emerrision effects that my Def Tech BP-30's give off. I wish they had better drivers that would produce more detail and clarity, though.
post #7 of 23
My coaxial build matches relatively well with the td12x build, and they are pretty stinking cheap to do as well smile.gif Check it out in the sticky speaker thread.
post #8 of 23
Why not build the QS8's with 2 smaller EOS or OS waveguides versus SEOS?
post #9 of 23
Thread Starter 
Quote:
Originally Posted by Erich H View Post

Why not build the QS8's with 2 smaller EOS or OS waveguides versus SEOS?

Not a bad plan.

How about this setup? A Klipsch design with a pair of TD6's and 4550's/EOS6's per enclosure.
post #10 of 23
bass addict I'll defiantly be following your build thread on these! I also have the QS8s and I'm just about to upgrade my LCR setup to the new JTR Noesis 228HT speakers and I was thinking that maybe I should look into upgrading my surrounds to something that can keep pace with the new JTR's.
post #11 of 23
Thread Starter 
Quote:
Originally Posted by jbrown15 View Post

bass addict I'll defiantly be following your build thread on these!

Well you can do the opposite if you want. biggrin.gif

OK, I went ahead and picked up four BMS4550s's (8 ohm), and four AE TD6m's (4 ohm). These will be setup in a bipolar arrangement with each wired in series for a final ohm load of 8 and 16 respectively.

Seeing as I have about a month before the tweeters arrive, I'd like to start working on the enclosure. My question is in regards to how critical in enclosure volume for surrounds. Win Isd shows a volume of about .8cf to reach .707 qtc. This requires an enclosure that is app 17 x 17 x 7. Now based on the limited width of my theater, I am trying to keep the surrounds as small as possible. That being said, function over form is still important.

So with XT32 and all the eq'ing capabilities of these new receivers, how high a qtc can one get away with, and still end up with a top sounding setup? I'm not going to spend good money on buying top of the line components, only to hinder them by putting it in the wrong enclosure. That being said; a smaller enclosure that blends in with the environment would be appreciated.
post #12 of 23
Thread Starter 
Input?
post #13 of 23
I wouldn't be so worries with Q as I would be with extension. As long as you can get to at least 80hz with high Q you're ok. If you have low Q maybe you could get away with 100hz.

And what about the cross over?
post #14 of 23
Thread Starter 
Quote:
Originally Posted by tuxedocivic View Post

I wouldn't be so worries with Q as I would be with extension. As long as you can get to at least 80hz with high Q you're ok. If you have low Q maybe you could get away with 100hz.

What would you define as high and low q?
Quote:
And what about the cross over?

Meaning? I will be having someone build the xover if that's what you are asking about.
post #15 of 23
I'd say 1.0 is quite high. And 0.5 is low. Not sure what the free air Q is.

Ok gotcha on the xo. The higher the Q the high the impedance peak moves up in frequency and this can actually make the high Q bump even bigger once combined with the first inductor in the cross over. It's minor, but another reason for lower Q.
post #16 of 23
How different is a crossover for a bipolar speaker compared to a regular convential speaker?
post #17 of 23
Every cross over is different, but there's generally no different way of designing it. I've never done one, but I'd design on one face's axis, and then measure the polar response. The polar response would be a necessary step in the design. It is in all designs actually, but some sloppy designs ignore it. For a bipole though, it would be mandatory I think.
post #18 of 23
BA,

Why do you want to drop QS8 ? Do you think they won't be able to keep up with the mains in terms of dynamics?

Since there are no proven DIY designs of this kind I am seriously thinking about getting a pair. Your advise is much appreciated.
post #19 of 23
Thread Starter 
Quote:
Originally Posted by zheka View Post

BA,

Why do you want to drop QS8 ? Do you think they won't be able to keep up with the mains in terms of dynamics?

Since there are no proven DIY designs of this kind I am seriously thinking about getting a pair. Your advise is much appreciated.

There is absolutely nothing wrong with the QS8. In fact it's one of the better surrounds I've heard (and I've heard a few). They have great sensitivity and play plenty loud.

My main reason was for the obvious benefit of timbre matching everything and my only complaint with the Axioms was they are a hair bit more diffuse than I'd like. I think a bi polar setup would allow me a little better directivity without the drawbacks of a mono polar setup in a smaller room such as mine.

From the guys I've talked to however, it sounds like working out a xover is no easy task. So I might stick with the QS8's and use the extra drivers to build some wide speakers. I could do a MMT setup and sell the 2 extra 4550's I'll have floating around. smile.gif
post #20 of 23
Bass addict, I must say for as much as I read in the speakers forum about all the negative things people are saying these days about Axiom speakers in general I have to say I really enjoy my QS8's in my theater room. I only use them for movies but they've been great so far.
post #21 of 23
Thank you guys. QS8 seem to be almost universally praised. I may just give it a try.
post #22 of 23
Thread Starter 
Quote:
Originally Posted by jbrown15 View Post

Bass addict, I must say for as much as I read in the speakers forum about all the negative things people are saying these days about Axiom speakers in general I have to say I really enjoy my QS8's in my theater room. I only use them for movies but they've been great so far.

I use them for hi res music as well, and while not the recommended direct radiator, I think they do pretty dang good.

Now this new setup I'm sure will bring to light all their flaws, but so far ignorance is bliss. biggrin.gif
post #23 of 23
It's funny you say that because that's one of my concerns with my upgrade to the new JTR Noesis 228 HT's for my LCR setup. That's why I was interested in your DIY surround build in the first place.
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