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Discussion Starter #181
What's up with the foam in the WG's in the geddes speakers? I was reading the very little bit they have about the speakers on his site and didnt see anything about it. Maybe i overlooked it. But ive seen other people use foam in their WG's as well. What type of foam and whats it suppose to do?
 

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Quote:
Originally Posted by reecew /forum/post/18217558


What's up with the foam in the WG's in the geddes speakers? I was reading the very little bit they have about the speakers on his site and didnt see anything about it. Maybe i overlooked it. But ive seen other people use foam in their WG's as well. What type of foam and whats it suppose to do?

Its all about the "HOMs", which in dummy terms for me just means the HONK of a horn. The foam and the design of the way guide eliminates the harsh sounds of the horn. Geddes calls that stuff HOMs but we can just call it the HONK. His Foam reduces the HOMs.




Here is a good thread that explains it for me.....

http://www.diyaudio.com/forums/multi...-fix-horn.html
 

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Discussion Starter #184
Regarding the celestion 1425 CD. I know its been measured, but has there been a x-over made for it with any sort of compensation/padding or anything like that? Or am just going to have to use a super generic 2-way w/ Lpad? Also can it be crossed at 2khz?
 

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Thanks for clearing that up for me, Dennis.

Quote:
Originally Posted by catapult /forum/post/18217101


All points on the profile are defined by the OS equation (at least until you get to the round-over at the mouth.) The farther you get from the throat, the more the OS approaches a straight line. Although it never quite gets perfectly straight, it gets close enough to call it straight for the purposes of practical construction.
 

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Quote:
Originally Posted by penngray /forum/post/18217755


I can have the waveguide above the woofer, correct?

Yes. That's just how I set it on the test stand for measurements.


Begins here, actually:

http://techtalk.parts-express.com/sh...78#post1624578

Quote:
Originally Posted by reecew /forum/post/18217853


Regarding the celestion 1425 CD. I know its been measured, but has there been a x-over made for it with any sort of compensation/padding or anything like that? Or am just going to have to use a super generic 2-way w/ Lpad? Also can it be crossed at 2khz?

Well, that's kinda the point, after all, isn't it...?
 

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Quote:
Originally Posted by reecew /forum/post/18217558


What's up with the foam in the WG's in the geddes speakers? I was reading the very little bit they have about the speakers on his site and didnt see anything about it. Maybe i overlooked it. But ive seen other people use foam in their WG's as well. What type of foam and whats it suppose to do?

Simply, the idea is that the sound "bouncing" around the horn will be attenuated more by it's multiple passes through the foam vs the direct sound which only passes through the foam once.


It's an open cell polyurethane 30 ppi foam.
 

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Discussion Starter #188

Quote:
Originally Posted by ZilchLab /forum/post/18218306


Well, that's kinda the point, after all, isn't it...?

You lost me lol. Whats the point, designing my own x-over?
 

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Quote:
Originally Posted by reecew /forum/post/18219005


You lost me lol. Whats the point, designing my own x-over?

Until proper filters are designed and validated for this particular combination of drivers, waveguide, and cab, chances are quite good it will sound like ass.


There's far more to successful design than slapping a random selection of components in a box....
 

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Discussion Starter #190

Quote:
Originally Posted by ZilchLab /forum/post/18219475


Until proper filters are designed and validated for this particular combination of drivers, waveguide, and cab, chances are quite good it will sound like ass.


There's far more to successful design than slapping a random selection of components in a box....

10-4 old chap! I know I know, lots of theoretical bs comes along with speaker building. Too bad it wast simpiler for dummies lol! Anyone know what WG was used when the celestion 1425 was test and where i can get ahold of the impedence charts and FR charts of the celestion? Im going to have to figure something out wing it posibly. Im stuck with the drivers once they arrive unless someone wants to take them off my hands lol.


EDIT: nevermind on the graphs search is your friend!
 

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First look soon, then I'll be doing the PCD thing with these.


Could have snugged the woofer and waveguide together more, but these ended up close to where the 10" QSC might, also.


This combo won't fit in New Large Advents 'cause their woofer cutouts are up higher, but there's plenty of room on the baffle of these originals, primary point being that getting up and running is no further away than ~$20 and a local thrift store, tag sale, CraigsList or FreeCycle listing....
 

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From midway between waveguide and woofer @ 44" mic distance, HF w/L-pad -3 dB:




[Random components stuck in a box....
]
 

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Quote:
Originally Posted by 900ss /forum/post/18226430


Looks pretty good to me. Any thoughts on the waveguide?

Sounds good; with 2510 closed box for HT, needs a sub, of course.


I've built with the PRX waveguides before, with the same "rippley" result using D220Ti:

http://www.audiokarma.org/forums/sho...00#post3341200


Brandon got similar using DE250 and a throat adapter; see his DriverVault.


With BMS 4540, his response was considerably smoother.


I'll run the vertical polars on this combo to see where it's at, then document the crossover and post the PCD design files.
 

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Discussion Starter #198

Quote:
Originally Posted by ZilchLab /forum/post/18228635

Sounds good; with 2510 closed box for HT, needs a sub, of course.

I've built with the PRX waveguides before, with the same "rippley" result using D220Ti:

http://www.audiokarma.org/forums/sho...00#post3341200


Brandon got similar using DE250 and a throat adapter; see his DriverVault.


With BMS 4540, his response was considerably smoother.


I'll run the vertical polars on this combo to see where it's at, then document the crossover and post the PCD design files.

Sounds good with random components stuck in the box? Or did you do some major x-over tweaking?
 

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Zilch,

I have noticed in your measurements that most of the designs come out to be around 90dB, while penn and augerpro seemed to have 100dB+ measurements. Am I missing something with this because your designs are about 10dB down. I am not insinuating anything either, just looking at the squiggly lines on the graphs.
 

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Quote:
Originally Posted by reecew /forum/post/18229870


Sounds good with random components stuck in the box? Or did you do some major x-over tweaking?

See the time stamps: I posted the raw driver data at 11:49 pm and the performance with a preliminary custom crossover at 3:30 am. Assume something happened in between there.


Quote:
Originally Posted by stgdz /forum/post/18229973


Zilch,

I have noticed in your measurements that most of the designs come out to be around 90dB, while penn and augerpro seemed to have 100dB+ measurements. Am I missing something with this because your designs are about 10dB down. I am not insinuating anything either, just looking at the squiggly lines on the graphs.

CLIO is calibrated here at a level referenced to where I can be in there taking measurements all day every day and not go deaf. You can see in the ZilchLab pics where the test stand is relative to the computer from which I run it. I had to wear hearing protection to get the raw data on the compression driver/waveguide, even with it padded down 3 dB. Noise floor is down around 40 dB; lower in the middle of the night.


[Doing this stuff is hazardous duty....
]
 
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