Hey guys...we need a little rallying here... - Page 229

About the smallest I could see working would be ~10" with 6 Dayton RS75T 3" mids below the SEOS-12 and a pair of 8" midbasses on the sides. It would obviously be a 3-way. The RS75T's are only 2.3" tall and you can fit 6 across easily. You could do 4 with a higher crossover point but you would lose some sensitivity.

When trying to maintain a timbre match across the fronts IMO it is as important to match the mid's as it is to match the highs. I would probably use the same drivers on the L/R but with the midbass's above and below instead of on the sides.

The real catch here is that no crossover is designed for this. Going active DSP would get very expensive with 9 amp channels.

One other possibilitiy would be a SEOS and a single pro 8" woofer to one side. This isn't something I've done and I haven't thought about it much so I don't really know what warts it might show. Directivity is obviously going to be a bit funky but I'm not sure what that translates to as far as actual performance.

I bought a Skill brand plunge router from Lowes for like $100. Works great.

The Ryobi RE180-pl is another cheap router that will get the job done, $99 at home depot. Its what I used for my quad subs. 

Would it help you to mount the waveguide outside or on top of the box? IDK if you could tolerate exceeding your dimensions with just the waveguide.......

I had a Home Depot gift card I wanted to use, and bought a Ridgid plunge router there, and have been happy with it - also about $100.

I had been PM'ed about a possible center channel for the MTG-08/Karma-8 design. If you could live with about +- 15 degrees of horizontal coverage when placed horizontally I simulated a 2.5 way MTM design based off the MTG-08 that could be made 9" high and sensitivity is bumped up into the mid 90's.

Also it would not be too bad setup vertical and used as mains or surrounds.

thats something i may be interested in. smaller footprint vs the big mal

Neat!

 

So, at a 12 foot distance, maybe the two middle seats are within the +/-15 degrees, and wider than that, they're more than 6dB down?

It's not that simple. Erich and I were batting around the idea of a center for a while and eventually decided it was to expensive.

You would have to look at the shape of the lobe, which should really be looked at with measurements. And also consider sidewall reflections. With a 2.5 way like mtg proposes, it's about the most cost effective way to do it with fewest compromises. But requires careful thought in the application. To say 6db down beyond 15 degrees is probably not correct. The nulls off axis are usually abrupt and deep.

Yeah it has its compromises; I am seeing almost -6dB at the crossover (1.6k) when you are ¼ the listening distance off center to each side for 12’ that would be about 3’ to each side. You might be able to get a usable 5-6’ window with the outer seats starting to hear the effects but like tux said move just a little beyond that and you are sitting right in the null.

LTD,

That's a pretty creative design. I wonder how well that would work for surrounds?

LTD, that is a possibility. It is basically a 4th order bandpass. This stuff can get tricky when modeling in hornresp because things like volume in front drivers can make a big difference at the frequencies we need. You might need to build up the area between in front of the cones. There could be lots of resonances to deal with.

I would actually do it with a slot on the top and bottom and 4 5-6" woofers. You could also add "rear" ports on the sides of the horn to make it a 6th order bandpass.

It is definitely a creative approach that IMO has merit. The issues are in the details which can be fairly complicated. A test box would be needed. Definitely not as trivial as a typical direct radiator.

Very clever LTD, and could work well. I've been studying maxmercy's thread and lilmike's threads with great interest.

As the mouth size goes down (as it would to keep baffle height within reason) the higher frequencies go up, so in this example it may work to your benefit. Max, I like the 6th order banpass, this would improve low-mid frequency extension, yes? So long as the compression ratio, mouth size, and the fold falls within the targeted enclosure size, this idea has potential to be something quite unique to the SEOS lineup. What would you consider for this, something with low Q? Whichever they are, the ratio will be high, and to maintain efficiency and have smooth response in upper midrange is key. TD6's with throat port maybe? Sorry my knowledge is limited, still learning hornresp...

I like it too.

How about upper and lower rows of 3" or 4" drivers, perhaps each tilted 45 deg to create a shallow V-shaped cavity.

Might be dicey, but perhaps the small height and depth of the driver cavity would keep phase cancellation under control above XO.

That sound similar to what Ive been playing with.
Couldnt figure out how to attach a sketchup file but if you search sketchup for SEOS Vifa tc9 it shoul pop up.

The model is pretty rough and doesnt show the cardoid loading Im considering in an attempt to lower the directed pattern down to 250hz or so.

That resembles some of the features of a Unity horn. Looks interesting for a center channel. If you make the box nice and wide and driven tapered like a Malcolm, you could get horizontal directivity to low mids and point source - ish behavior. Short wide ports above and below fed by rows of small mid drivers. . The little Gento 2inchers might be a fit for the mids (if you use enough of them). Just thinking out loud...

More than a few do this in the pro market, especially with vertical/line array boxes. As with any such effort, it has a few possible pitfalls and benefits, with execution being key. The slot can make for a noticeable point of diffraction on the face, and the chamber can cause response changes and/or resonances which need to be dealt with. In general, the deeper the slot vs. the opening area, the more issues encountered.

The slot could be made a little deeper to allow rounding over onto the baffle.

It might require rear mounting, but if the opening is reduced in height until the distances are less than 1/4 wavelength, there ought not be any resonances.

Might doing this increase efficiency a la AMT?

Assuming AMT really does that; has that been verified, or is the efficiency just from greater radiating area?

Figured it out,

I think you guys are way over complicating the compact center idea. Just make it a 3 way! A row of six 2" drivers (Vifa TC6?) should be able to barely fit on a 9" baffle with the SEOS being 6.5" high. Couldn't the recess for the waveguide go to the very top of the baffle instead of leaving room at the top? A 6.5" - 8" woofer could then be placed on each side of the box and crossed in around 200-300hz.

Is there any way to know the weight of the speakers?

I want to wall mount mine.

That's exactly the method I was considering, but cost creeps up quickly that way. Ltd02's idea keeps it compact and 2-way. Although I think the construction complexity isn't worth it. I'd just eat the cost and go 3-way like you say. I was going to do SEOS12/DNA-205 over a few mids flanked by Eminence alpha 8a's. That gets a 4 ohm load, but about 97db/2.83V/m, about 9 or 10" tall, 80hz F3 sealed, and about $300. Just need to find a reasonable mid and I'd do it.

Quick question:

Will two 15s(side by side) work under a SEOS 12? What would the tradeoffs be in this situation?

I think not, nottaway. It's like the horizontal MTM center. The 15" is so big you'll have destructive interferences at modest angles in the 700 to 1000hz range. You be somewhat ok if you crossed low (like 900 to 1000hz) and made it a 2.5 way, but then you're faced with crossing where the CD may have power handling issues and directivity match issues.

Haha TV, you punned

I figured as much.

Sounds like id need the BFD750 on a 24" SEOS to make that work.

BTW i think that would be super sexy! Maybe a pair of 12s under that 24" horn......

Heck yes, that would be sweet lookin'...black FG SEOS-24's w/BA-750 and a pair of TD12's. Come to daddy!

Thats What I'm Talkin about!

You could also jump in the new project Matt and I are talking about starting now...SEOS 24 with dual 15s underneath

If anyone is going to order the SEOS-24, they need to contact me fairly soon. The pallet is nearly full. In a week or so I'm going to go ahead and order random things to fill the rest of the pallet so we can get it completed.