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Hey guys...we need a little rallying here... - Page 24

post #691 of 7503
12/20/10 at 10:53am
Guys I think the elliptic throat idea is a non-starter, at least in my humble opinion. I am not even sure there is a benefit. I haven't seen that proven. This is an idea that IMO complicates more than need be. With the EOS and SEOS, starting with circular the wall angle changes with direction so that the mouth ends up elliptical or superelliptical while following the OS formula, so I think it is just obsessing.
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post #692 of 7503
12/20/10 at 11:08am
+1
SEOS-15 9060 N=3 (rH=12cm, rV=4.5) Elliptical flange
penngray
3amrecords


Quote:
Originally Posted by penngray View Post

Thanks, I think the important parameters have been hashed out I see little reason not to with the

SEOS-15 9060 N=3 (rH=12cm, rV=4.5) Elliptical flange


as the first prototype? Any more thought on the throat being round to match the CD??

Quote:
Originally Posted by penngray View Post

Optimum isnt going to help us much since the elliptical CD choices are very limited and probably very expensive.

So the throat is circular and its angle is going to match the B&C DE250??

I think this was agreed upon, but it is a good idea to check it.
If we can get the throat to match 1 CD perfectly, and it is the one most of us are going to use then I see this is a good compromise.
If everyone cannot agree on this, then we should just make the throat an even match to as close to as many choices as possible, though this is a less than optimal solution.
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post #693 of 7503
12/20/10 at 11:09am
Thanks Max. I did read it being agreed upon but I always think its nice to ask 10 more times.

I think the throat angle is a very important part of the design so I wanted to triple check for EricH.

What I would like is for it to match a very popular high quality CD. I think the B&C DE250 is that choice. I think the Beyma CP380 has a similar angle so we are okay.
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post #694 of 7503
12/20/10 at 11:25am
+1
SEOS-15 9060 N=3 (rH=12cm, rV=4.5) Elliptical flange - Circular throat - Throat angle to match the 15* driver exit angle of the DE250

penngray
3amrecords
coctostan

Also, Erich, were you planning to make complete molded baffles and separate WGs? I'd be more interested in the separate WG, but I'd probably buy a few of each.

Edit: Beyma CP385 and BMS 1" drivers have pretty similar angles.
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post #695 of 7503
12/20/10 at 11:30am
Quote:
Originally Posted by penngray View Post

Thanks Max. I did read it being agreed upon but I always think its nice to ask 10 more times.

I think the throat angle is a very important part of the design so I wanted to triple check for EricH.

What I would like is for it to match a very popular high quality CD. I think the B&C DE250 is that choice. I think the Beyma CP380 has a similar angle so we are okay.

I know, that is the same thing I am doing. The more times we toss an idea around the room the more times we sometimes forget what has all ready been worked out.
So taking a moment to re-verify everything along the way is always a much needed sum-up conversation.

That way we know, when people agree on something or even simply "Quote and +1" we know that most of us are in agreement.
That way we move on to the next step and start to over analyze it, break it down and get this WG working like we all want.
Every time we all come to a group decision on a design factor we are one step closer to what we all want, and one step closer to pushing this into the Prototype phase, and closer to having one in our hands to measure, model, xover, and hell even listen to and enjoy.

/side note
Also, this opens up a bunch of opportunities for those of us who would like to come back and reference this thread of ideas and come build off of one of the tangents at a (far) later date when this project is complete.
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post #696 of 7503
12/20/10 at 11:35am
Quote:
Originally Posted by coctostan View Post

Beyma CP385 and BMS 1" drivers have pretty similar angles.

I know I know nothing about most CD's and I have never personally heard any of these CD's so I am simply going off of what most other people like, find pleasing, or the ones who simply have better documented performance.

It is good to know that the CD that has been decided upon; (B&C DE 250), Has (somewhat) close throat dimensions to other CD's people might end up using, this will be great to measure A/B to other CD's to see how this WG as a WG alone affects multiple CD's.

That way people who can measure and have access to other CD's can tell if this works well with some of the other alternatives.
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post #697 of 7503
12/20/10 at 11:37am
Quote:
Originally Posted by coctostan View Post

+1
SEOS-15 9060 N=3 (rH=12cm, rV=4.5) Elliptical flange - Circular throat - Throat angle to match the 15* driver exit angle of the DE250

penngray
3amrecords
coctostan

Also, Erich, were you planning to make complete molded baffles and separate WGs? I'd be more interested in the separate WG, but I'd probably buy a few of each.

Edit: Beyma CP385 and BMS 1" drivers have pretty similar angles.

At first I think the guys building this will just be doing separate waveguides. I'm going to be contacting them no later than tomorrow with all the specs.

How do you guys want this to mount exactly? Do you want the roundover on the WG to flow smooth into a rectangular flange for mounting? Or is it better to just have the roundover come directly down and sit right into your recessed cut out on the baffle? Did that make sense?
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post #698 of 7503
12/20/10 at 11:38am
Quote:


That way people who can measure and have access to other CD's can tell if this works well with some of the other alternatives.

When I get one I will be shipping it off to Augerpro for measurements if he will still do them. He has a great collection already so I would like to add these measurements to his collection. I will send my Radian 475B, BMS4550 and Celestion 1745 along for testing if he is interested in more then one CD.
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post #699 of 7503
12/20/10 at 11:40am
Quote:
Originally Posted by Erich H View Post

At first I think the guys building this will just be doing separate waveguides. I'm going to be contacting them no later than tomorrow with all the specs.

How do you guys want this to mount exactly? Do you want the roundover on the WG to flow smooth into a rectangular flange for mounting? Or is it better to just have the roundover come directly down and sit right into your recessed cut out on the baffle? Did that make sense?

will the waveguide roundover be "raised" on the baffle a little bit?

I would like the option that allows me to extend waveguide mouth smoothy to a 1 1/4" roundover on a baffle. I do not want any "lip" or "raise" point where diffraction is created.
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post #700 of 7503
12/20/10 at 11:58am
Quote:
Originally Posted by penngray View Post

will the waveguide roundover be "raised" on the baffle a little bit?

I would like the option that allows me to extend waveguide mouth smoothy to a 1 1/4" roundover on a baffle. I do not want any "lip" or "raise" point where diffraction is created.

+1

I'd like it mount similar to the QSC. Basically flush with the baffle. That is the most versatile. If someone wants to run it free, flush to a roundover, flush to a sharp edge or in a baffle wall it will work.
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post #701 of 7503
12/20/10 at 12:08pm
Why BC250? BMS4538 for instance is cheaper and also uses Mylar with a lower mass thus extends to 30kHz instead of 16kHz.

Gentleman - do you know that the gap between WG and driver is unmeasurable even if clearly seen with a naked eye? Don't be overwhelmed with details You'll spend much more time on passive crossover.

Depth for SEOS is constant - 12cm. It comes form 90deg coverage having roundover 12cm and 15" mouth. Vertical height can be adjusted. It was said 8" is good so I've changed rV to 4.5cm. I can lower if you like.
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post #702 of 7503
12/20/10 at 12:30pm
Quote:
Originally Posted by penngray View Post

Thanks, the roundover discussion is a little confusing so I want to make sure its known that most will be installing this flush on baffle.

The discussion about radius/roundover assumed a flush termination with the baffle. It is just the radius of the transition between the OS throat to the baffle edge.
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post #703 of 7503
12/20/10 at 1:20pm
Quote:
Originally Posted by penngray View Post

Why wouldnt we just keep the same height as what already exists with the QSC HPR-152i, which is 10"?? Of course I didn't see that size listed.

10" is what Jzagaja tried to match with the original EOS-15. When I did the initial mock-ups the favorite was the SEOS horn that I had stretched, and not a real option Jzagaja had modeled. I thought it would be possible to just expand the rV value closer to the original EOS-15, however that is not the case, as that horn would technically be considered a 90x90 pattern design at the radius of rV=12cm, though it will not actually hold control to 90 in the vertical. It was a design choice to try and match the original 15"x10" size parameter.

Hence all the back and forth discussion between me and him regarding rV values. As it turns out in order to get the taller SEOS look while maintaining pattern control and negating the axial dip, we had to go to a larger vertical coverage of 60degrees, which then dictates a optimum rV of 4.5cm, combined getting us closest to what everybody originally chose.

Diemensions of the 4 options:

EOS-15: 15" x 10.3"

SEOS 90x60 N=3: 15" x 7.2"

SEOS 90x50 N=4: 15" x 5.7"

SEOS 90x45 N=2.5: 15" x 5.2"
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post #704 of 7503
12/20/10 at 1:41pm
Quote:
Originally Posted by jzagaja View Post

Depth for SEOS is constant - 12cm. It comes form 90deg coverage having roundover 12cm and 15" mouth. Vertical height can be adjusted. It was said 8" is good so I've changed rV to 4.5cm. I can lower if you like.

Quote:
Originally Posted by LBDiver View Post

10" is what Jzagaja tried to match with the original EOS-15. When I did the initial mock-ups the favorite was the SEOS horn that I had stretched, and not a real option Jzagaja had modeled. I thought it would be possible to just expand the rV value closer to the original EOS-15, however that is not the case, as that horn would technically be considered a 90x90 pattern design at the radius of rV=12cm, though it will not actually hold control to 90 in the vertical. It was a design choice to try and match the original 15"x10" size parameter.

Hence all the back and forth discussion between me and him regarding rV values. As it turns out in order to get the taller SEOS look while maintaining pattern control and negating the axial dip, we had to go to a larger vertical coverage of 60degrees, which then dictates a optimum rV of 4.5cm, combined getting us closest to what everybody originally chose.

Diemensions of the 4 options:

EOS-15: 15" x 10.3"

SEOS 90x60 N=3: 15" x 7.2"

SEOS 90x50 N=4: 15" x 5.7"

SEOS 90x45 N=2.5: 15" x 5.2"


It's good to know that we have actuall WxHxD measurements on these WG's.

I am still set on the
SEOS 90x60 N=3: 15" x 7.2"
Depth is a moot point at this point for me. The Depth of the 3015 is 173mm (3012 is 143mm) compared to the wg's depth of 120mm + 62mm (for the DE250)
So, WG+CD = 182mm versus 173/143mm for the drivers.
That is a difference of 9mm/39mm
39mm is roughly 1.5 inches.
So even if you end up using the 3012 size, or whatever is (somewhat close in depth) you will not have that much of a depth difference, so either way you will need to worry about woofer clearance before WG/CD clearance inside of an enclosure.
(Plus having a little wiggle room in the back is always nice for thermal and physical connection reasons.)
*All measurements set to mm to make things easier.
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post #705 of 7503
12/20/10 at 2:38pm
ok, sanity check here guys....

something looks wrong to me. EOS of 90º x 60º should be exactly the same height and width as a SEOS 90º x 60º. Why is the height of one great than the other? That doesn't make sense unless the roundovers were different for the two, and again, why is that?
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post #706 of 7503
12/20/10 at 2:43pm
Quote:
Originally Posted by coctostan View Post
I used this formula:

half angle between nulls = arcsin (xover freq wavelength/2*ctc spacing)

For a 1000hz xover and 12 CTC my calcs show a 34 deg half angle or a 68deg window. The axis angle and shape of this lobe between the nulls is a function of the crossover.
That's the Linkwitz equation I use as well. If you want to match the nulls at edge of the WG's directivitiy in this case 60deg, you can just solve (XO wavelength/2D)= .5 since Arcin(.5)=30deg.

Therefore if we add a 3/8" flange beyond the edge of the SEOS 90x60 N=3 the overall size would be 7.2" + .75"= ~8" for the horn. Add and double the minimum gap of say .5" x 2 = 1", so 9" for the horn total.

.5 = (wavelength/ 9" + Driver diameter)

or

(9 + Driver Dia)/2 = Wavelength

So for a B&C 12HPL76 = 12.4" 21.4/2 = 10.7in = 1267hz

JBL 2226J = 15.26" 24.26/2 = 12.13in = 1119hz


Seems we are right in the target range here. If people want to push a lower XO while maintaining the 60deg vertical nulls they can just increase the gap between the driver and WG.
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post #707 of 7503
12/20/10 at 2:57pm
Quote:
Originally Posted by AudioJosh View Post
ok, sanity check here guys....

something looks wrong to me. EOS of 90º x 60º should be exactly the same height and width as a SEOS 90º x 60º. Why is the height of one great than the other? That doesn't make sense unless the roundovers were different for the two, and again, why is that?
Josh,

This was the whole issue I was trying to figure out with Jzagaja. The original EOS-15 uses a 12cm rH and rV. This was to make the size as close to the requested 15"x10" which came from the QSC dimensions. The value of rV=12cm is ideal for 90deg coverage, so it would be considered a 90x90 horn, but as you'll see in the FR graphs Jzagaja posted it truly only holds directivity to ~50deg.

Once we switched from EOS to SEOS he was always using the optimal radius based on the vertical window we were giving which was 45-50deg (which was rV=3cm), and no longer trying to force a given height of the WG.

Since everybody voted for the taller SEOS mock up, in order to reach that expanded height and therefore an increased optimal rV you have to increase the vertical directivity. So by jumping to 60deg vertical, rV=4.5cm becomes optimal, giving us a taller WG with larger transition radius.
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post #708 of 7503
12/20/10 at 3:15pm
Quote:
Originally Posted by 3AMRecords;19679617I think this was agreed upon, but it is a good idea to check it. If we can get the throat to match 1 CD perfectly, and it is the one [B
most of us are going to use[/b] then I see this is a good compromise.
Agreed. If the entry angle isn't matched to the exit angle of one of the known-high-performing CD's, then I am not interested.

As for which one, I don't care. B&C, BMS, Beyma, as long as it's a fairly current model that's likely to be around for a few years. Push comes to shove my preference would be for the cheaper and/or smaller (shallower) of them, because I want my next speakers to be the same depth as my current ones (~9") or less.

Quote:
Originally Posted by jzagaja View Post
Depth for SEOS is constant - 12cm. It comes form 90deg coverage having roundover 12cm and 15" mouth. Vertical height can be adjusted. It was said 8" is good so I've changed rV to 4.5cm. I can lower if you like.
Thanks. That's good to know. So with a B&C 250 we're looking at an ~18.5cm deep HF unit (~16cm if one counts after the front baffle), and with the BMS 4550 we're looking at ~2cm less. That sounds good.
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post #709 of 7503
12/20/10 at 3:19pm
Quote:
Originally Posted by LBDiver View Post

Since everybody voted for the taller SEOS mock up, in order to reach that expanded height and therefore an increased optimal rV you have to increase the vertical directivity. So by jumping to 60deg vertical, rV=4.5cm becomes optimal, giving us a taller WG with larger transition radius.

I hope those mock ups that were posted towards the end here won't confuse the project. I had a bad feeling about that when they were posted. People would vote on looks versus sound quality, which is what may have happened. And then it turned out not to be a feasible design and things went a different direction. I hope the project doesn't get changed too much just so it looks like a mock up.

We're after sound quality first. At least I hope so.
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post #710 of 7503
12/20/10 at 3:27pm
We are after SQ with an elliptical or quasi-elliptical OS waveguide that will minimize or eliminate the on-axis notch, using a commonly-available compression driver that is well accepted.

DE250, available world-wide, is that driver, in my view....
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post #711 of 7503
12/20/10 at 3:43pm
Quote:
Originally Posted by Erich H View Post
I hope those mock ups that were posted towards the end here won't confuse the project. I had a bad feeling about that when they were posted. People would vote on looks versus sound quality, which is what may have happened. And then it turned out not to be a feasible design and things went a different direction. I hope the project doesn't get changed too much just so it looks like a mock up.

We're after sound quality first. At least I hope so.
Same OS principals, all with optimal transition radius', just a difference in vertical directivity. If somebody wants more limited vertical they can vote for on of the others with this. Personally I was happy with the original EOS.

So what other details do you need hashed out before you can move forward?? Does the flange have to be final on the proto from Jzagaja or can we just have him make the horn with say a small extended lip say 3/8 or 1/2" all the way round, and if it's decided later to go wider, rectangular, your guys on this side can make that adjustment in the final mold? Same could apply to the throat angle, CD flange, once you get the prototype different angles could be tested by turning alternate ones out of MDF or Aluminum. Are you planning to have the CD bolt flange and throat cast as all one resin part with the WG itself, where the flange will be only resin?
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post #712 of 7503
12/20/10 at 3:49pm
Quote:
Originally Posted by ZilchLab View Post
We are after SQ with an elliptical or quasi-elliptical OS waveguide that will minimize or eliminate the on-axis notch, using a commonly-available compression driver that is well accepted.

DE250, available world-wide, is that driver, in my view....
I agree, and you don't have to go through a Pro Parts supplier to get them.

Zilch are you happy with SEOS 90x60 N=3 ??
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post #713 of 7503
12/20/10 at 4:26pm
Quote:
Originally Posted by LBDiver View Post
Does the flange have to be final on the proto
Yes, I'm hoping to have it all finalized.
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post #714 of 7503
12/20/10 at 6:12pm
Quote:
Originally Posted by Erich H View Post

Yes, I'm hoping to have it all finalized.

Tell us what you all you need, ie what's still variable, and lets take a final vote with options.

I say SEOS 90x60 N=3 with 3/8-1/2" additional flange lip added to the perimeter of the current profile, Aluminum mount 2/3 bolt pattern for DE250.
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post #715 of 7503
12/20/10 at 6:26pm
Quote:
Originally Posted by jzagaja View Post

Why BC250? BMS4538 for instance is cheaper and also uses Mylar with a lower mass thus extends to 30kHz instead of 16kHz

BMS's are very nice but the 4538/4540nd don't play very low. BMS suggests a 1.9khz crossover and I can't imagine using it lower than 1.5-1.6khz. I'm planning to use them in a much smaller waveguide crossed around 2khz.
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post #716 of 7503
12/20/10 at 7:23pm
Quote:
Originally Posted by LBDiver View Post

Tell us what you all you need, ie what's still variable, and lets take a final vote with options.

I say SEOS 90x60 N=3 with 3/8-1/2" additional flange lip added to the perimeter of the current profile, Aluminum mount 2/3 bolt pattern for DE250.

I think that's pretty much what everyone wants. Just not sure about the flange portion yet. But I'm not sure that's a huge deal, as long as it mounts smooth with the front baffle, it should be okay.

It's pretty much what LTD02 type up a few pages ago.
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post #717 of 7503
12/20/10 at 11:48pm
Quote:
Originally Posted by coctostan View Post
SEOS-15 9060 N=3 (rH=12cm, rV=4.5) Elliptical flange - Circular throat - Throat angle to match the 15* driver exit angle of the DE250

penngray
3amrecords
coctostan
noah
It would probably help move things along if everyone who agrees adds their name to the list even though they already said they did.
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post #718 of 7503
12/20/10 at 11:51pm
Quote:
Originally Posted by Erich H View Post
How do you guys want this to mount exactly? Do you want the roundover on the WG to flow smooth into a rectangular flange for mounting? Or is it better to just have the roundover come directly down and sit right into your recessed cut out on the baffle? Did that make sense?
hmmm....they both make sense, but it seems they both need to be recessed into the baffle, so.....

So I vote for the first one
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post #719 of 7503
12/21/10 at 3:51am
I vote for a flange that takes the shape of the SEOS and simply extends past far enough for mounting. I don't think we need it to be rectangular. I'm not sure I've seen anyone vote for it that way. For those that want to make a visually appealing speaker, I'd think this would be the only route.
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post #720 of 7503
12/21/10 at 4:25am
SEOS-15 9060 N=3 (rH=12cm, rV=4.5) Elliptical flange - Circular throat - Throat angle to match the 15* driver exit angle of the DE250

penngray
3amrecords
coctostan
noah
bwaslo
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