Hey guys...we need a little rallying here... - Page 13 - AVS Forum
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DIY Speakers and Subs > Hey guys...we need a little rallying here...
penngray's Avatar penngray 04:58 PM 12-06-2010
Quote:
Originally Posted by LTD02 View Post
just for sake of comparison, does anybody know (or can somebody measure) the total width of the qsc 152i horn?
its 10"x14"!

LTD02's Avatar LTD02 03:45 PM 12-07-2010
thanks penn.

so guys, what are the next steps here?
penngray's Avatar penngray 03:56 PM 12-07-2010
Im waiting on Eric H to tell me if those EOS 15" files I sent him are helpful or not.
Erich H's Avatar Erich H 09:54 PM 12-07-2010
There is work going on behind the scenes, I'm just waiting on a few responses from some people I've talked to.

Penngray, about the file that you sent me: I assume that matches the photo you posted? Is that exactly what everyone wants?

For now, are we looking for just a baffle mounted unit that screws on? Or are we going with one that either glues on with no screw holes, or mounts a different way?
A9X-308's Avatar A9X-308 11:05 PM 12-07-2010
I would personally vote for bolt on to the baffle so that when correctly routed in and rebated it is flush. that way it can get re-used in other future projects easily.

CD mount; flat flange not screw on.
DL86's Avatar DL86 03:22 AM 12-08-2010
Quote:
Originally Posted by a9x-308 View Post

i would personally vote for bolt on to the baffle so that when correctly routed in and rebated it is flush. That way it can get re-used in other future projects easily.

Cd mount; flat flange not screw on.

+1
LTD02's Avatar LTD02 04:59 AM 12-08-2010
+1
bwaslo's Avatar bwaslo 06:06 AM 12-08-2010
+1 too
LTD02's Avatar LTD02 06:25 AM 12-08-2010
"There is work going on behind the scenes, I'm just waiting on a few responses from some people I've talked to."

:-) perhaps you could provide some updates on the behind the scenes work so that we have some sense of what is going on. without any info, we are in the dark.
Erich H's Avatar Erich H 06:51 AM 12-08-2010
Quote:
Originally Posted by LTD02 View Post

"There is work going on behind the scenes, I'm just waiting on a few responses from some people I've talked to."

:-) perhaps you could provide some updates on the behind the scenes work so that we have some sense of what is going on. without any info, we are in the dark.

I'm in the dark right now too, I'm waiting for responses on the building process.
LTD02's Avatar LTD02 06:57 AM 12-08-2010
:-) that is good info erich. at least knowing that we are all in the dark together is cool. thanks. if you could, just drop an update every day or two. that way we have some sense of what is going on, even if it is just an "i'm still waiting" type post. not sure if i have said it, but thanks for stepping up and taking the lead on this one.
penngray's Avatar penngray 07:08 AM 12-08-2010
Quote:
Originally Posted by Erich H View Post

There is work going on behind the scenes, I'm just waiting on a few responses from some people I've talked to.

Penngray, about the file that you sent me: I assume that matches the photo you posted? Is that exactly what everyone wants?

For now, are we looking for just a baffle mounted unit that screws on? Or are we going with one that either glues on with no screw holes, or mounts a different way?

IMO, We should be only doing bolt on designs. I guess having a flat flange for baffle surface mounting is a good idea too.

Those files I sent you do match this.


LTD02's Avatar LTD02 02:39 PM 12-09-2010
looking at that again penn, i'm wondering if the eos is going to create more high order modes than the round os horn.
penngray's Avatar penngray 03:17 PM 12-09-2010
Quote:
Originally Posted by LTD02 View Post

looking at that again penn, i'm wondering if the eos is going to create more high order modes than the round os horn.

You would have to explain. I honestly have no idea. I go off the following fact that Geddes built the best waveguide design out there. He recommends the OS shape and he says the EOS would help because of the CTC issue that some care about.

Its really the only reason to care about using the EOS, other then it also looks nicer then square waveguides.

IF people think Geddes is full of hot air then they are not going to be overly concerned with using the OS shape either.
LTD02's Avatar LTD02 07:04 PM 12-09-2010
high order modes are refelections in the horn.

bouncing around like this.



in the horizontal, only one reflection. not a problem.

in the vertical, lots of reflections. potential problem.

the round horn and the foam eat up hom's, but we don't have good data, holding all else equal, not sure if they are even a problem.

i'm not making a statement here, just kicking out something for debate.
LL
LBDiver's Avatar LBDiver 07:44 PM 12-09-2010
Regarding HOM's, somebody should e-mail Cornell and ask them to find 'um since they're testing speakers and 3D sound, having rated Geddes' Summa's top of the heap so far.
penngray's Avatar penngray 07:08 AM 12-10-2010
Quote:
Originally Posted by LBDiver View Post

Regarding HOM's, somebody should e-mail Cornell and ask them to find 'um since they're testing speakers and 3D sound, having rated Geddes' Summa's top of the heap so far.

Any links for that test?
LBDiver's Avatar LBDiver 01:38 PM 12-10-2010
Finally found it, Zilch had posted it on PE. My original info was a bit off, it is Princeton and they tested the Nathan not the Summa.

http://www.princeton.edu/3D3A/Directivity.html

For info on their "Pure Stereo - Audiophile-grade 3D Sound" research click on >Research >Projects.
coctostan's Avatar coctostan 01:41 PM 12-10-2010
I don't know the specifics on the Geddes speakers but don't they throw a narrower than 90deg pattern? I've heard 70deg but I can't recall for sure. If so, assuming LTD's theory is correct, wouldn't it have more HOMs compared to a 90deg OSWG?
penngray's Avatar penngray 01:42 PM 12-10-2010
Quote:
Originally Posted by LBDiver View Post

Finally found it, Zilch had posted it on PE. My original info was a bit off, it is Princeton and they tested the Nathan not the Summa.

http://www.princeton.edu/3D3A/Directivity.html

Thanks, I knew about that one. I was hoping someone did the Summa.
penngray's Avatar penngray 01:44 PM 12-10-2010
You know, looking at the EOS picture, the horizontal pic looks OS and the verical pic looks Exponential (I think?? I definitely does not look OS). I guess that is the way EOS waveguides are shaped though.
LTD02's Avatar LTD02 01:48 PM 12-10-2010
"You know, looking at the EOS picture, the horizontal pic looks OS and the verical pic looks Exponential "

i think that is because in the vertical, its pretty much all roundover. that's one reason why i kept bringing up using a smaller roundover.
LBDiver's Avatar LBDiver 01:50 PM 12-10-2010
Quote:
Originally Posted by penngray View Post

Thanks, I knew about that one. I was hoping someone did the Summa.

My bad, sorry to get your hopes up.

Regarding this EOS, what's the consensus on the ratio of OS vs roundover, are we sticking with the original design?

Thought's on having an elliptical flange, instead of rectangular, and having a router template made?

EDIT: Damn I'm slow, LTD I agree a "in-between" roundover should be investigated. I believe Jzagaja modeled 2cm and 15cm (which this is), what does 9 or 10cm model like??
penngray's Avatar penngray 01:53 PM 12-10-2010
good point LTD02! Thanks!

LB, Im not sure what people wanted a complete baffle with the EOS 15" molded into it with smooth roundover transition might be a great choice.

I wish I did consulting work for some manufacturing companies that made moldings I would have had a prototype made already.
LTD02's Avatar LTD02 02:09 PM 12-10-2010
the princeton study appears to just measure directivity. don't they understand that horns have all kinds of different pattern control? maybe i read it wrong, but how many ways are there to read this:

"If you know of any loudspeakers that may have higher directivity than the current winner of the directivity contest..."

jbl 2356 has 40x20 directivity. is that really what they are shooting for at princeton???
penngray's Avatar penngray 02:15 PM 12-10-2010
Who knows, I didnt find it very meaningful for what we are doing.
ZilchLab's Avatar ZilchLab 03:35 PM 12-10-2010
Quote:
Originally Posted by penngray View Post

Who knows, I didnt find it very meaningful for what we are doing.

Lateral reflections mess up their 3D decorrelation paradigm, and perhaps vertical, as well; they want narrow constant directivity.

You can read off their polars what Nathan actually is. Yes, narrower than 90°.

They have not stated a particular target, only that the other designs measured there do not comply with their needs as well as Nathan. They appear unaware that 60° x 40° is a commonly available constant-directivity pattern, and may also not yet know what their actual requirements might be. I am working up something for about 1/10 the cost of Nathan, but they have not responded to my eMails. It seems unlikely at this point that any member of their team is aware of EconoWave, either.

[Yes, it came from "Zilch;" they're just gonna have to get past that.... ]
penngray's Avatar penngray 03:47 PM 12-10-2010
Yeah, too bad they didnt have anyone browsing through DIY forums they might have found all these threads very interesting and maybe could have picked your brain on some of it.
penngray's Avatar penngray 03:48 PM 12-10-2010
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
LBDiver's Avatar LBDiver 04:38 PM 12-10-2010
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


The 18Sound WG's seem to perform consistently well, it's too bad they cost so much (comparatively to the QSC etc.). The price seems to preclude anybody from trying the large ones, that and that they require a 1.4" CD. I want to see/hear what the XR1496 90x60 horn sounds like, it's supposed to hold CD down to 1.2kHz in both directions.
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