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Old 4th December 2010, 11:48 AM   #5021
AllenB is offline AllenB  Australia
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I face a bit of group delay due to my waveguide's centre distance. At one point my drivers are over 90 degrees out of phase and I suffer a moderate on axis dip just below 1kHz.

To what point can I safely ignore the dip and just aim for the right power response in that region?
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Old 4th December 2010, 05:03 PM   #5022
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Steer the forward axis to the desired angle in the crossover (maximal inverse null), measure the resulting usable (-6 dB) forward lobe height, and decide if you're willing to accept that....
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Old 10th December 2010, 05:15 PM   #5023
jzagaja is offline jzagaja  Poland
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Thanks to Jean-Michel spectrograms of an 12" OS and JMLC-1000 using BMS 4538.
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Old 10th December 2010, 08:10 PM   #5024
jzagaja is offline jzagaja  Poland
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And FR plot for 30 deg off axis.
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Old 17th December 2010, 05:27 PM   #5025
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Quote:
Originally Posted by gedlee View Post
Just to be clear, I did, but I found that there was no value in it for me. I believe that this is why there aren't any on the market right now. It seems like a simple part, and maybe it is if you have a lot of money for tooling, etc. but in small lots its very expensive and people just don't want to pay a price that is interesting to a manufacturer.

Some time ago there was a long thread about making waveguides. The overwhelming postion at that time was that they would be easy to make and that I was just gouging the market. OK, where are they then? That thread was the reason that I stopped selling them. Simply put the waveguide, foam plug and mounting plate are the key to what I make and sell and represent the greatest value-added by far. I am not willing to give this away without due compensation for this value added.

I don't make stand alone waveguides, they are molded into a custom baffle. It is extra work for me to cut them out. I have, and will, sell the baffles with foam plug and mounting plate. Just contact me on the side because I do not advertise this. But be fore warned, they are not cheap.
I probably shaved a couple years off my life breathing all the chemicals, and nearly chopped off my right thumb too. But I've made a pile of waveguides, and I posted the instructions on how to build your own over on htguide. I'm too lazy to google it, but the instructions are over there if anyone wants to build their own.

Having said that, I value my time (and my fingers) and I just bought a pair of Summas after screwing around with the DIY route for a while.
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Old 17th December 2010, 05:36 PM   #5026
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Doug, you're sure acting strangely here lately, seeming to want to pin things down into absolutes. No absolutes exist in audio, (or in most things). The geddes compromises are different from those of "Econowave" and each will have their proponents. I'm surprised none of the other Ewavers have tried my foam solution- there's obvious ripple at cutoff with that horn and it's well controlled with my foam without expanding CTC...
Check out my "homster" thread on here. My experience with treating the mouth of a horn was a real revelation. I spent the better part of a decade obsessing over the geometry of the curve, without ever realizing that the termination of the throat and the mouth is hugely important.

Good to see you're seeing improvements in the measurements, and hearing improvements in the room.

This stuff works!
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Old 20th December 2010, 12:22 PM   #5027
doug20 is offline doug20  United States
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Quote:
Originally Posted by Patrick Bateman View Post
I probably shaved a couple years off my life breathing all the chemicals, and nearly chopped off my right thumb too. But I've made a pile of waveguides, and I posted the instructions on how to build your own over on htguide. I'm too lazy to google it, but the instructions are over there if anyone wants to build their own.

Having said that, I value my time (and my fingers) and I just bought a pair of Summas after screwing around with the DIY route for a while.
We can source 12" OSWG for around $100 now next solution is going to be a 15" SEOS. I have always disagreed that it can not be done.

Geddes won't be the only OS waveguide choice any more.
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Old 20th December 2010, 01:08 PM   #5028
AllenB is offline AllenB  Australia
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A question about the 18sound XT1086. Early reports were that it was a diffraction horn but it looks somewhat like an OS. Is this true?

Has anyone used it down below 1kHz with any success?


Quote:
Originally Posted by doug20 View Post
We can source 12" OSWG for around $100 now next solution is going to be a 15" SEOS. I have always disagreed that it can not be done.

Geddes won't be the only OS waveguide choice any more.
Living across the pond, there hasn't been an ideal option that I've been aware of. What product are you talking about?
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Old 20th December 2010, 01:21 PM   #5029
doug20 is offline doug20  United States
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Living across the pond, there hasn't been an ideal option that I've been aware of. What product are you talking about?
There has been a group buy waveguide thread for a long time. They have started shipping what was being offered, one was the 12" OSWG. Across the pond should be a good thing for shipping costs from poland.



There is a new discussion on AVSForum.com looking for a better OS design. The 15-SEOS is being finalized now. We are hoping for manufacturing in the US instead of Poland though since shipping will be cheaper. I see the solution being cheaper then $100 in the end.



Quote:
A question about the 18sound XT1086. Early reports were that it was a diffraction horn but it looks somewhat like an OS. Is this true?

Has anyone used it down below 1kHz with any success?
You might want to search Zilch's thread on techtalk

Flex Your PCD Mettle: - Techtalk Speaker Building, Audio, Video, and Electronics Customer Discussion Forum From Parts-Express.com
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Old 21st December 2010, 07:05 PM   #5030
doug20 is offline doug20  United States
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Here is an updated picture of the prototype

Click the image to open in full size.

Looks like kind of like the popular QSC HPR152i waveguide (Which isnt sold any more, that could change too).
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