Hey guys...we need a little rallying here... - Page 16 - AVS Forum
First ... 14  15  16 17  18  ... Last
DIY Speakers and Subs > Hey guys...we need a little rallying here...
bwaslo's Avatar bwaslo 01:35 PM 12-13-2010
I was thinking that the elliptical/rectangular discussion at this point was just about the outline of the lip, what mounts to the baffle, not the shape of the guide. I'd rather mount a rectangle than an ellipse or super-ellipse to a cabinet front, but the waveguide itself I'd rather have an EOS or SEOS contour. Are we going with a roundish outline at the front?

AudioJosh's Avatar AudioJosh 01:36 PM 12-13-2010
Quote:
Originally Posted by penngray View Post

What really is the optimal deg for vertical coverage?

I think Zilch had data towards this answer in terms of a reasonable forward lobe for a given XO frequency.
AudioJosh's Avatar AudioJosh 01:37 PM 12-13-2010
Quote:
Originally Posted by bwaslo View Post

I was thinking that the elliptical/rectangular discussion at this point was just about the outline of the lip, what mounts to the baffle, not the shape of the guide. I'd rather mount a rectangle than an ellipse or super-ellipse to a cabinet front, but the waveguide itself I'd rather have an EOS or SEOS contour. Are we going with a roundish outline at the front?

The mount could be a rectangle, but for the actual waveguide we were discussing super-ellipse. Of course, we'd have to ask Jack if that were doable.
bwaslo's Avatar bwaslo 01:42 PM 12-13-2010
I like super-ellipse. Heck, I like the QSC which is super-hyper-gawdawful ellipse (i.e., rectangle entirely). But it would be good to try for something that might be better, so SEOS would be interesting.
jzagaja's Avatar jzagaja 02:02 PM 12-13-2010
Updated SEOS-15 (90x50, n=4).
LL
AudioJosh's Avatar AudioJosh 02:31 PM 12-13-2010
Thanks for doing that. Very interesting. Kind of reminds me of a bigger JBL PT WG in some ways. No sharp corners but still quasi rectangular.

Couple of observations:
I think it is important to not be too quick to look at them and dismiss the differences. The difference in roundover in the horizontal versus vertical plays tricks on the eyes in terms of differences. If you study the area "scooped" by the various profiles I think the differences are better illuminated.
ZilchLab's Avatar ZilchLab 03:00 PM 12-13-2010
Quote:
Originally Posted by AudioJosh View Post

I think Zilch had data towards this answer in terms of a reasonable forward lobe for a given XO frequency.

On this point, I'm going to fall back upon Wayne Parham's discussions in his Pi-Speakers forum, and my own communications with him.

In practical design terms, the vertical pattern control may be "augmented" by the vertical nulls in the transition region, lessening the impact of the narrower vertical mouth height of the asymmetric design. Yes, it begins losing pattern control at a higher frequency, but the nulls can "fill it in" a bit there, if the crossover frequency vs. CTC distance are adjusted to accomplish a smooth transition. In an optimum design, I can achieve a +/- 20° (-6 dB) forward lobe.

Generally, 90° x 40° - 60° has been the standard for constant-directivity horns and waveguides, but note that Geddes axisymmetric OS designs are somewhat narrower, more like 70°, in part as a consequence of his directivity not being as "constant" as more conventional designs. JBL PT, QSC, and others do meet -6dB spec for the most part, however....
penngray's Avatar penngray 03:37 PM 12-13-2010
Quote:
Originally Posted by AudioJosh View Post

Thanks for doing that. Very interesting. Kind of reminds me of a bigger JBL PT WG in some ways. No sharp corners but still quasi rectangular.

Couple of observations:
I think it is important to not be too quick to look at them and dismiss the differences. The difference in roundover in the horizontal versus vertical plays tricks on the eyes in terms of differences. If you study the area "scooped" by the various profiles I think the differences are better illuminated.

The only differences I will care about is taking the impulse file and plugging it into a wavelet formula. I would like to see the differences in that compared to all others previously created.
penngray's Avatar penngray 03:43 PM 12-13-2010
Quote:
Originally Posted by bwaslo View Post

I was thinking that the elliptical/rectangular discussion at this point was just about the outline of the lip, what mounts to the baffle, not the shape of the guide. I'd rather mount a rectangle than an ellipse or super-ellipse to a cabinet front, but the waveguide itself I'd rather have an EOS or SEOS contour. Are we going with a roundish outline at the front?

EricH and I have discussed two options.

1. extending the waveguide (no matter what that shape) creating a flat flange that will allow use to mount on a baffle.

2. Rounding over the top, left, right sides of the waveguide creating the rounded edges of the baffle.


#1 creates more HOMs but is easier to work with and allows us to all select our own roundovers (if we do them at all, Zilch does not and I would).


#2 is much more specific and harder IMO since the round over of the woofer portion has to match the horn round over if the baffle is continous. I use 1 1/4" roundovers so Im not sure that will match the roundover on the waveguide.
noah katz's Avatar noah katz 04:13 PM 12-13-2010
Doesn't a 15" wide WG with 10" woofers either waste the low freq pattern control of the WG or XO's them at a freq where the patterns don't match?

Quote:
Originally Posted by penngray View Post

I just spent a little bit of time going over many waveguide options that exist and I just realized that maybe the XT1464 is really the waveguide I need. I always end up back with what Paul W did with that horn. It meets the most of my requirements.

http://www.htguide.com/forum/showthr...ghlight=raptor
"Tweeters are 18 Sound ND1460A, horns are the 18 Sound XT1464"

http://www.eighteensound.it/index.as...roduct&pid=177


3AMRecords's Avatar 3AMRecords 04:33 PM 12-13-2010
Quote:
Originally Posted by penngray View Post

EricH and I have discussed two options.

1. extending the waveguide (no matter what that shape) creating a flat flange that will allow use to mount on a baffle.

2. Rounding over the top, left, right sides of the waveguide creating the rounded edges of the baffle.

I am not sure what you mean by option #2. Though, if it is what I am thinking you mean, I know this would mean more work on the wood working aspect, but I think it would look awesome.

Do you have any pictures of a design similar to this?

Max
craigsub's Avatar craigsub 04:57 PM 12-13-2010
Penngray - Thanks for the link.

The guy in charge of handling issues for CHT was off today, so I will try again tomorrow.
Erich H's Avatar Erich H 05:04 PM 12-13-2010
Quote:
Originally Posted by 3AMRecords View Post

I am not sure what you mean by option #2. Though, if it is what I am thinking you mean, I know this would mean more work on the wood working aspect, but I think it would look awesome.

Do you have any pictures of a design similar to this?

Max

It would be more work and likely be a specialized product after we try to get the regular baffle mount option made up. Not everyone would use something like that and it would actually be fairly expensive to make (but certainly neat). I think most people are expecting #1. Just something that mounts easily like the QSC, but with a better performing shape.

So is Zilch and everyone now leaning more towards the SEOS-15 as a better design?
coctostan's Avatar coctostan 05:09 PM 12-13-2010
Quote:
Originally Posted by AudioJosh View Post

Thanks for doing that. Very interesting. Kind of reminds me of a bigger JBL PT WG in some ways. No sharp corners but still quasi rectangular.

I don't have any data to back it up, but my theory is that JBL goes with the odd assymetrical shape to further minimize the null most greatly experienced with the circular mouth. It would take some serious clout to manufacture something that complex though. I'm not sure I could see anyone outside of JBL doing it.

So we are primarily looking at a horn with a better flare, a true OS profile and better mouth transition than what QSC provided. I think that provides significant potential to build some world-class speakers.
penngray's Avatar penngray 05:30 PM 12-13-2010
Quote:
Originally Posted by 3AMRecords View Post

I am not sure what you mean by option #2. Though, if it is what I am thinking you mean, I know this would mean more work on the wood working aspect, but I think it would look awesome.

Do you have any pictures of a design similar to this?

Max

Sorry no picture of #2, trying to explain the flange as simply being the roundover covering the front baffle.

I forgot there is a #3 having the horn do a complete 360 roundover like the Le Cleache horns and just having the horn mounted free standing by itself without a box around it. Very European looking.
ZilchLab's Avatar ZilchLab 05:31 PM 12-13-2010
Quote:
Originally Posted by noah katz View Post

Doesn't a 15" wide WG with 10" woofers either waste the low freq pattern control of the WG or XO's them at a freq where the patterns don't match?

Yes, most decidedly, and it takes away some very useful options for generating a smooth, directivity-matched transition between woofer and waveguide.

I've got my own gig, of course, and I'm trying not to unduly influence the overall design here. I've worked with waveguides 24" and 30" wide, so I know the drill....
penngray's Avatar penngray 05:34 PM 12-13-2010
Quote:
Originally Posted by Erich H View Post

It would be more work and likely be a specialized product after we try to get the regular baffle mount option made up. Not everyone would use something like that and it would actually be fairly expensive to make (but certainly neat). I think most people are expecting #1. Just something that mounts easily like the QSC, but with a better performing shape.

So is Zilch and everyone now leaning more towards the SEOS-15 as a better design?

Now thinking about it I see little reason to do both an EOS-15 and an SEOS-15. If the SEOS-15 is hypothetically superior then we should go with that one instead.

Is there a reason to do both?
penngray's Avatar penngray 05:40 PM 12-13-2010
Quote:
Originally Posted by noah katz View Post

Doesn't a 15" wide WG with 10" woofers either waste the low freq pattern control of the WG or XO's them at a freq where the patterns don't match?

You simply need to find the matching pattern. I doubt Paul W> built his design worrying about directivity pattern matching at the XO. Its one of those choices again.

We can push the waveguide down to where it loses pattern control and we can XO there knowing that the woofer has 360 deg pattern control ( some call this no directivity, I call it 100% directivity because its constant for 360 degrees).

No one is building 90deg pattern control below the waveguide XO anyways, are they? Geddes XOs his Abbeys and Summas below 900Hz and he has 12" and 15" woofers involved, the transition to the woofer is obviously the same for his as any other design that XOs where the woofers still have control on and off axis.

You have to decide if pattern matching is more important then XO screwing up the critical voicing area. I will choose XO placement as a more important aspect of the design. I guess I want the XO below 800Hz or above 2500Hz to keep it out of the critical range.
Erich H's Avatar Erich H 05:44 PM 12-13-2010
Quote:
Originally Posted by penngray View Post


Is there a reason to do both?

Maybe to compare them.
penngray's Avatar penngray 05:46 PM 12-13-2010
Yes, good point. I would love to run measurements on both to put the HOM debate to bed.
ZilchLab's Avatar ZilchLab 05:48 PM 12-13-2010
Quote:
Originally Posted by penngray View Post

You simply need to find the matching pattern. I doubt Paul W> built his design worrying about directivity pattern matching at the XO. Its one of those choices again.

I'll say it again -- Raptors have issues; I would not build them, and they're not a flag I would be waving, by any means.


Quote:
Originally Posted by penngray View Post

No one is building 90deg pattern control below the waveguide XO anyways, are they?

Not other than the dipole fans, but for sure, you don't want it jumping from 90° to 360° in the transition region. That lies at the very heart of directivity matching.

You need to move out of the abstract and into the real, practical, and most importantly, optimal, here, Penn....
LTD02's Avatar LTD02 05:52 PM 12-13-2010
"I doubt Paul W> built his design worrying about directivity pattern matching at the XO. Its one of those choices again."

i asked him about this and he conceded that they did not match. however, they do so many other things right, that they sound great.

[edit: i see z. already responded. i concur.]
penngray's Avatar penngray 05:56 PM 12-13-2010
Quote:
Originally Posted by ZilchLab View Post

Not other than the dipole fans, but for sure, you don't want it jumping from 90° to 360° in the transition region. That lies at the very heart of directivity matching.

You need to move out of the abstract and into the real, practical, and most importantly, optimal, here, Penn....

I have never been in the abstract or theory arena. I buy, build and test.

Again, its choice. Im not reading too many complaints from larger waveguide/horn owners. I have posted many times that everyone has too choose their compromise.

Im at the point in my speaker building world that I believe the #1 priority is to keep the XO out of the critical voicing range somewhere around 700Hz up to 2500Hz. Im definitely not interested in XOing any design in the 1000Hz to 2000Hz range any more.

I already know you compromises are different then mine
LTD02's Avatar LTD02 05:57 PM 12-13-2010
the only concern that i have with the super elliptical is the jbl waveguide closest to that form factor has 3-d contours on the sides. jbl put them there for a reason. i would assume that reason was a good one. perhaps without them, the geddes dip starts to show up the frequency response???

as in this one:
http://www.jblpro.com/catalog/genera...?PId=166&MId=2
noah katz's Avatar noah katz 05:58 PM 12-13-2010
Quote:
Originally Posted by Erich H View Post

So is Zilch and everyone now leaning more towards the SEOS-15 as a better design?

I'm in favor of the SEOS.
penngray's Avatar penngray 05:59 PM 12-13-2010
Quote:
Originally Posted by LTD02 View Post

"I doubt Paul W> built his design worrying about directivity pattern matching at the XO. Its one of those choices again."

i asked him about this and he conceded that they did not match. however, they do so many other things right, that they sound great.

Thanks. I figure that would be the answer.

Im sure JBL owners that have HUGE horns are okay with the compromise of directivity transition being sub-optimal.

Its really amazing how many compromises exist in each design. The real pedantic designer types must go crazy over this stuff
LTD02's Avatar LTD02 06:01 PM 12-13-2010
"Im at the point in my speaker building world that I believe the #1 priority is to keep the XO out of the critical voicing range somewhere around 700Hz up to 2500Hz. Im definitely not interested in XOing any design in the 1000Hz to 2000Hz range any more."

the larger horns lose pattern control about the same as a 15" woofer, so what happens is that directivity is well matched across a large range of frequencies. choose the one that is lowest for your horn and c.d. this is what the 4722 do and i suspect the system that mk is running right now.
penngray's Avatar penngray 06:03 PM 12-13-2010
Quote:
Originally Posted by LTD02 View Post

the only concern that i have with the super elliptical is the jbl waveguide closest to that form factor has 3-d contours on the sides. jbl put them there for a reason. i would assume that reason was a good one.

as in this one:
http://www.jblpro.com/catalog/genera...?PId=166&MId=2

Then we are just back to the JBL PT waveguides originally in the Econo Waveguides. That means we are back to HOMs, etc.

I think we can agree that JBL does not agree or car about Geddes opinion on HOMs. JBL designs like that simply honk according to Geddes.

This means we are either agreeing with the concept behind HOMs or we are not. Im going with Geddes approach myself because many horns do sound horrible to me. I want controlled directivity, high sensitivity, low distortion without the honk sound.

See the link in post #405 for many measurements (no OS waveguides though )
noah katz's Avatar noah katz 06:04 PM 12-13-2010
What XO freq does the Raptor use?

How about putting the two woofers next to each other, and angled wrt each other to form a virtual driver width that matches the WG.
penngray's Avatar penngray 06:10 PM 12-13-2010
Quote:
Originally Posted by noah katz View Post

What XO freq does the Raptor use?

How about putting the two woofers next to each other, and angled wrt each other to form a virtual driver width that matches the WG.

Here is a quote from Paul W
Quote:


The crossover was lowered from 900Hz to 700Hz for a smoother woofer/tweeter directivity transition.

http://www.htguide.com/forum/showthr...2&page=1&pp=35

And if you look at the measurements, I think its safe to say the direcitivity mismatch discussion is a little overblown (atleast to me).

Btw, cool idea with the drivers but I think its a lot of extra work that won't offer much in terms of real audible differences.
First ... 14  15  16 17  18  ... Last

Up
Mobile  Desktop