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DIY Speakers and Subs > AVS Group Project......Speaker Name: SEOS Maximus
pokeme's Avatar pokeme 05:39 PM 05-17-2014
Quote:
Originally Posted by Stumbo View Post

If you really want to do something different...

This ported running up to 250hz...

http://www.parts-express.com/bc-21sw115-4-21-neodymium-subwoofer-4-ohm--294-691

Topped by this covering 250hz-900hz
http://audioroundtable.com/forum/index.php?t=msg&th=16581&prevloaded=1&&start=0

All topped off with a ba750 loaded seoes15.

Full range, does 130db program, and doesn't blow your 1,000 budget by too much. Big speaker at 24"wide x 48"high x24" deep.

That horn really makes it look dominating :-)

Rebel975's Avatar Rebel975 05:59 PM 05-17-2014
Quote:
Originally Posted by LTD02 View Post

erich, across the past few years, you have become the expert on creative ways to cnc cut these things.

do you think it would be possible to make this design as a 3 piece baffle, kind of like this (to facilitate shipping)?



the idea would be that the mid panel would either mount from the back ("innie") or sit on top of the main baffle ("outtie") depending on what folks think looks best (with edges rounded over of course).



I like this idea.
383-s-10's Avatar 383-s-10 07:17 PM 05-17-2014
What if the woofers at the bottom were at an angle facing forwards to keep the width down (trapezoid or triangle shaped base).
pokeme's Avatar pokeme 07:28 PM 05-17-2014
Quote:
Originally Posted by 383-s-10 View Post

What if the woofers at the bottom were at an angle facing forwards to keep the width down (trapezoid or triangle shaped base).

If you do that you create a quasi bipole speaker if I follow what you are saying.
FriscoDTM's Avatar FriscoDTM 07:43 PM 05-17-2014
I was looking at something like the Tempests for my new fronts but this looks much more appealing. Subscribed.
Thomas-W's Avatar Thomas-W 08:09 PM 05-17-2014
Quote:
Originally Posted by LTD02 View Post

anyway, i noticed those ripples in the impedance plot too and was wondering if that is just the price that one pays for having high sensitivity drivers similar to the way that the frequency response tends to be more ragged for high sensitivity drivers than it does for some others.

it seems that at least to some extent damping and sensitivity go hand in hand (but from opposite directions), so is this just the price to be paid for high sensitivity or is there a such things as a high sensitivity driver that is also very well damped?

OR, may it even be in part a measurement artifact because with the same power the high sensitivity driver is moving more, producing higher spl, and all the rest of it? so if the drive level of spl were normalized would the impedance plot show more similar ripple?

We see these differences regardless of the type of driver. So it's just another variable to consider when making driver choices.

What I just noticed in the FaitalPRO plots they're using a different scale for their plots compared to other mfgrs. So once again we must do our own testing to compare apples to apples
A9X-308's Avatar A9X-308 11:27 PM 05-17-2014
Quote:
Originally Posted by pokeme View Post

If you do that you create a quasi bipole speaker if I follow what you are saying.
No you won't. The radiation pattern at lower midbass is still omni and below a couple of hundred Hz or so it won't make the slightest difference if the driver is on the front or the side of the baffle. Think AR9, NHT 3.3 etc.
A9X-308's Avatar A9X-308 11:41 PM 05-17-2014
Quote:
Originally Posted by LTD02 View Post

seos 15 with quad 8's in a sealed enclosure with something like a 150-250 or so f3/q=0.707 would allow them to be run with no high pass crossover components.
I really like your suggested design, except for this bit. Though a sealed enclosure will limit the ultimate excursion they will do, they will still be trying to excurse further than they need to, potentially creating more distortion than if they were appropriately high passed.

Damn. I had a set of bedroom speakers designed and then you guys come along with this. I have about half the parts for a W/2M/WG design on hand and the better controlled directivity would be an advantage. It'd work out cheaper too.
pokeme's Avatar pokeme 11:53 PM 05-17-2014
Quote:
Originally Posted by A9X-308 View Post

No you won't. The radiation pattern at lower midbass is still omni and below a couple of hundred Hz or so it won't make the slightest difference if the driver is on the front or the side of the baffle. Think AR9, NHT 3.3 etc.

He said woofers (plural), the picture above only shows mid woofers as being in multiples. I'm also going to disagree that below a couple hundred hertz is omni because I can pretty easily locate a sub pumping out above 100hz. Some people are a bit picky that way.
A9X-308's Avatar A9X-308 12:01 AM 05-18-2014
Quote:
Originally Posted by pokeme View Post

He said woofers (plural), the picture above only shows mid woofers as being in multiples. I'm also going to disagree that below a couple hundred hertz is omni because I can pretty easily locate a sub pumping out above 100hz. Some people are a bit picky that way.
So locating a pair of drivers on the side of the enclosure, is going to locate the sound.... to the enclosure. Something very different to having a sub running up to 200Hz on the sidewall of the room.

And if there are a pair of drivers on the side of the enclosure, it still doesn't make them bi-poles.



These are AR9s and they have a 12" driver on each side of the enclosure at the bottom and they are not bi-poles.
pokeme's Avatar pokeme 12:21 AM 05-18-2014
A driver firing on opposite sides of a box in phase is the very definition of bipolar.
LTD02's Avatar LTD02 12:45 AM 05-18-2014
alpha niner is talking about the radiation pattern. once you get low enough, the pattern from two opposed drivers no longer radiates like a figure 8, but more like a single source. its never perfect, but 90 degree off axis radiation is pretty omni for below a couple hundred hz for most drivers.
pokeme's Avatar pokeme 12:50 AM 05-18-2014
That's true, but the initial post I was replying to involved the mid ranges being arranged in such a manner.
LTD02's Avatar LTD02 01:01 AM 05-18-2014
a far more boring, but more traditional approach to the original specs might simple be a seos12/12" driver/21" driver combo with a rotatable top section which would allow for horizontal mounting.

not a new idea, just another one to kick into this particular pot for consideration.



horizontal center channel.


i agree that the 21sw115 is the better option for something like this. takes better advantage of the large cabinet. at about 2' wide 3.5' tall and ~2' deep, there should be plenty of room to let the woofer breath and tuning could be pretty low without a terribly long port.

sw115 in 12 cubic foot cab tuned to 22hz.


not the highest sensitivity in the upper bass, but that's the tradeoff for good extension.

here is a pair of 2226h 15" drivers in a 12 cubic footer tuned to 33hz (orange line, picture below). less extension, but higher sensitivity for most of the bass range.

such a tradeoff is something that nobody likes to think about, but it is there. don't want folks to build the 21" mega main only to find out that their buddy's 2x15 has a lot more 'bass'.


LTD02's Avatar LTD02 01:02 AM 05-18-2014
"That's true, but the initial post I was replying to involved the mid ranges being arranged in such a manner."

roger.
LTD02's Avatar LTD02 01:26 AM 05-18-2014
"What if the woofers at the bottom were at an angle facing forwards to keep the width down"

that would work fine.

it is usually done when aesthetics are taking the front seat because a narrow cab is also a smaller cab and smaller cabs have the better looks, but lower sensitivity/efficiency on the low end.
Martycool007's Avatar Martycool007 05:22 AM 05-18-2014
Have any of you guys checked out the new drivers from BMS? Specifically, the BMS-4508? It is a coax ribbon that has high sensitivity, decent power handling, and can extend low enough to cross to a 12" or possibly even a 15" woofer!

Another interesting driver is the new Fountek NeoCD3.5. It is a high sensitivity ribbon that can be purchased with an optional waveguide and used pretty low for a ribbon. Plus, it cost under a $100 and seems to do a lot of things right, perhaps similar to the Beyma TPL-150 for much less money! A Seos-24 + Radian 950PB and a pair of decent woofers with the Fountek ribbon covering every thing above say 4,000hz might be something to consider!
LTD02's Avatar LTD02 06:17 AM 05-18-2014
the 4508 appears to be designed for line arrays. pretty neat driver. vertical dispersion of ~15 degrees means that you would have to pretty much be on axis vertically or you won't hear much.
Erich H's Avatar Erich H 07:43 AM 05-18-2014
Quote:
Originally Posted by LTD02 View Post

a far more boring, but more traditional approach to the original specs might simple be a seos12/12" driver/21" driver combo with a rotatable top section which would allow for horizontal mounting.

not a new idea, just another one to kick into this particular pot for consideration.



horizontal center channel.


i agree that the 21sw115 is the better option for something like this. takes better advantage of the large cabinet. at about 2' wide 3.5' tall and ~2' deep, there should be plenty of room to let the woofer breath and tuning could be pretty low without a terribly long port.

When I posted that design a few pages back with the SEOS-18, Tux said there probably wouldn't be much reason to do that over a Fusion-12.

I've got about 10-15 different layouts and will post them all in the same place soon. You might have missed the MTM over the 18" or 21" woofer drawing I posted. It gets the waveguide at the correct level and doesn't have 2 mid woofers side by side. Not sure if that's a good idea or not.

One reason why I'd rather do one cabinet is to take advantage of all the internal volume that's left there behind the mids and waveguide. You lose all of that once a smaller box is built to sit on top of the sub.


There's a good chance this will be a passive top with a actively powered bottom.

I also had a worry about cabinets getting too tall. Hopefully they're too big to fit behind acoustic screens....if by some chance this design actually pans out really good.
pokeme's Avatar pokeme 08:02 AM 05-18-2014
How much extra would it cost to integrate the waveguide into the baffle for a more sexy looking arrangement? Might have more "high end" market appeal too if that's even a consideration.

Maybe even a trim piece that surrounds the edges of the waveguide and extends onto the lip a tiny bit (like the rubber in a car door gutter seal). Just a bit of extra pinache.
bwaslo's Avatar bwaslo 09:06 AM 05-18-2014
Quote:
I've got about 10-15 different layouts and will post them all in the same place soon. You might have missed the MTM over the 18" or 21" woofer drawing I posted. It gets the waveguide at the correct level and doesn't have 2 mid woofers side by side. Not sure if that's a good idea or not.

I don't like MTMs with big waveguides much. My first shot at a quasi-econowave tried to use four 4" midwoofs, two each above and below the Ewave waveguide. Didn't work well at all, (verticaI performance was terrible). I ended up taking it apart and putting the waveguide above all four woofers (and had only the top pair of woofers playing near the crossover frequency). When doing an MTM, don't forget that after the waveguide/tweeter has rolled off below its crossover, the critical CTC distance becomes the distance between the woofers above and below. Either the tweeter has to cross in very low, the tweeter has to be very small, or one set of midwoofs has to cut in considerably lower than the other set.

If I'm to do the crossover honors (which isn't necessary by any means of course) it would have to all be done within about 2 months, so custom molded baffles, hard to get ribbons and drivers, and the like would pretty much take me out of the picture.

I'd vote for a SEOS18 over a 15" over a 21" (big woofer crossed active crossover and power amp). Or it the goal is just a celebration of testosterone, instead go for the whole kabuki thing and put drivers wherever and however and make it big and loud.!
tuxedocivic's Avatar tuxedocivic 09:12 AM 05-18-2014
Hey Bill, you could still half way the mids in an above/below layout.
bwaslo's Avatar bwaslo 09:33 AM 05-18-2014
True, but then what's the advantage? That makes it harder to get the waveguide on the listening axis without going too tall. It would distribute the bass better for floor reflections I suppose.

It would seem like it would make more sense to cross (half cross) instead to a larger driver below, that bumps up everything higher off the ground.
tuxedocivic's Avatar tuxedocivic 09:37 AM 05-18-2014
The CTC distance of a larger driver reintroduces the vertical problem at the XO you mentioned??

And yes, distribution and vertical directivity would be my reason for above/below mids. And especially woofers.
jeno's Avatar jeno 10:39 AM 05-18-2014
Quote:
Originally Posted by Martycool007 View Post

Have any of you guys checked out the new drivers from BMS? Specifically, the BMS-4508? It is a coax ribbon that has high sensitivity, decent power handling, and can extend low enough to cross to a 12" or possibly even a 15" woofer!

It's not a ribbon.
Quote:
Originally Posted by jeno View Post

It may look like a ribbon driver but is really a 459x coaxial compression driver coupled to a apparatus to bend the wave to a planar wave in order to fit in live sound line arrays.

LTD02's Avatar LTD02 08:25 AM 05-19-2014
"When I posted that design a few pages back with the SEOS-18, Tux said there probably wouldn't be much reason to do that over a Fusion-12."

yeah...that's pretty much all that one is. just has the "sub" built into the same cabinet for mostly aesthetic purposes. separating it out probably makes more performance sense, but there is something about the aesthetic of the "all in one" cab that has some sort of appeal. can't really explain it...but it does.


"Or it the goal is just a celebration of testosterone, instead go for the whole kabuki thing and put drivers wherever and however and make it big and loud.!"

that certainly seems like the spirit of this project.

a big cab with four woofers crossed in around 700hz might work ok if one sits far enough back. kind of like the jbl theater cabs...but with twice as many woofers!



kind of like the one in this pic on the left, but a smaller horn.




the benefit would be that with the right 15" driver, sensitivity would be VERY high and in a corner/up against a wall, would probably have over 100db 1w1m sensitivity down into the 20's, so even with a typical AVR, the thing would have crushing output. red line is the 21sw115 for comparison.



jbl theater cabs for comparison.





alternatively the top woofer could be used for an octave or so below (e.g. 350-700hz or so) with the other woofers rolling in underneath thus providing for downward sloping overall frequency response and eliminating two problems: 1 the giant choke of a very low crossover on the woofers and 2 the vertical spacing to the center of the four woofers.

if the bass is a little rich, tone control could be used to back it down relative to the mid/top without losing the sensitivity. most avr's have at least some sort of 'bass' tone control. hhmmm...
pokeme's Avatar pokeme 09:40 AM 05-19-2014
Quote:
Originally Posted by LTD02 View Post

"When I posted that design a few pages back with the SEOS-18, Tux said there probably wouldn't be much reason to do that over a Fusion-12."

yeah...that's pretty much all that one is. just has the "sub" built into the same cabinet for mostly aesthetic purposes. separating it out probably makes more performance sense, but there is something about the aesthetic of the "all in one" cab that has some sort of appeal. can't really explain it...but it does.


"Or it the goal is just a celebration of testosterone, instead go for the whole kabuki thing and put drivers wherever and however and make it big and loud.!"

that certainly seems like the spirit of this project.

a big cab with four woofers crossed in around 700hz might work ok if one sits far enough back. kind of like the jbl theater cabs...but with twice as many woofers!



kind of like the one in this pic on the left, but a smaller horn.




the benefit would be that with the right 15" driver, sensitivity would be VERY high and in a corner/up against a wall, would probably have over 100db 1w1m sensitivity down into the 20's, so even with a typical AVR, the thing would have crushing output. red line is the 21sw115 for comparison.



jbl theater cabs for comparison.





alternatively the top woofer could be used for an octave or so below (e.g. 350-700hz or so) with the other woofers rolling in underneath that providing for downward sloping overall frequency response and eliminating two problems: 1 the giant choke of a very low crossover on the woofers and 2 the vertical spacing to the center of the four woofers.

if the bass is a little rich, tone control could be used to back it down relative to the mid/top without losing the sensitivity. most avr's have at least some sort of 'bass' tone control. hhmmm...

 

Is that a slot port/foot for the speaker to rest on too? Very neat.


LTD02's Avatar LTD02 11:38 AM 05-19-2014
not sure if something like this is possible/feasible with a passive network. 2.5 way concept, but instead of just accentuating the bass, it is covering a good part of the midrange too and using the midrange woofer as more of a 'fill'.

green line is ba750, second order net.
red line is woofer right under horn, second order low pass in such a way to extend the frequency response down to about 550hz or so where it would meet with
black line is 3 woofer 'bottom end' (.5) second order low passed about an octave lower than the midrange woofer.
magenta line is where it all ends up, net. though i'm not sure with phase if that that is what you'd actually get.
passive gurus, is this possible/feasible?

I suppose that the crossover point from the bottom woofers to the midwoofer would have to be sufficiently low to keep the side-by-side pair from beaming, which at about 30" would be pretty low, perhaps 500hz or so for a 90 degree pattern. then again cornet placement would solve that problem. so maybe a little lower than in the picture.


Scott Simonian's Avatar Scott Simonian 12:00 PM 05-19-2014
Looks familiar. biggrin.gif


John, you're the man!
tuxedocivic's Avatar tuxedocivic 01:47 PM 05-19-2014
Its a good idea but you would probably run into unpleasant phase issues. Would probably make more sense to high pass the upper woofer with a second order to get phase in check. Then you might as well use a proper midrange. Then you're into 3 way. Which is better I think as you wouldn't need the low end out of the upper woofer with that much fire power in the lower woofers. A true 2.5 way tries to save the hassle of high passing and doubles the bass capability, but forfeits a dedicated mid. I'm not sure that's required here.

Thoughts?
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