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Old 15th May 2008, 02:00 PM   #131
EspenE is offline EspenE  Norway
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I'm in line for one of your waveguide kits. Since I live in Norway, I plan to buy the waveguides/baffles only, and source drivers here in Europe.

As I understand it, the full kit is for a 10" waveguide and a 10" speaker (you have mentioned the B&C 10ps26).

My question: will I compromise the design if I used a 12" speaker instead of the 10-inch? Does the different polar response on the 12" matter - compared to the 10-inch?

(I construct my own crossovers, and have OK measuring facilities).

Thanks, Espen
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Old 15th May 2008, 02:37 PM   #132
gedlee is offline gedlee  United States
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Quote:
Originally posted by EspenE
I'm in line for one of your waveguide kits. Since I live in Norway, I plan to buy the waveguides/baffles only, and source drivers here in Europe.

As I understand it, the full kit is for a 10" waveguide and a 10" speaker (you have mentioned the B&C 10ps26).

My question: will I compromise the design if I used a 12" speaker instead of the 10-inch? Does the different polar response on the 12" matter - compared to the 10-inch?

(I construct my own crossovers, and have OK measuring facilities).

Thanks, Espen

In my opinion you will compromise the design if you do your own crossover. Thus, if you insist on doing that it makes no difference what woofer you use.

My waveguides are simply not that easy to do crossovers for and I use techniques that are beyond even capable DIY's. Its all custom software that I have assembled over decades and a lot of experience.

I would NOT suggest changing my design. Build it as specified.
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Old 15th May 2008, 03:42 PM   #133
LAL is offline LAL  United States
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Earl,
This last post about crossover construction is why I earlier suggested that you only offer completed crossovers with your kits. People subsequently listening to completed kits cannot tell that the heart of the design-the crossover-has been modified from the original, and for better or worse will believe it to be your work. A poorly done modification will only have negative effects on the public perception of your work.
LAL
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Old 15th May 2008, 05:51 PM   #134
EspenE is offline EspenE  Norway
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Quote:
Originally posted by LAL
Earl,
This last post about crossover construction is why I earlier suggested that you only offer completed crossovers with your kits. People subsequently listening to completed kits cannot tell that the heart of the design-the crossover-has been modified from the original, and for better or worse will believe it to be your work. A poorly done modification will only have negative effects on the public perception of your work.
LAL

In a sense, I agree on that. I'm sure that Earl's crossover and the chosen units is the best for his design. No disagreement on that. And I intend to build it just as specified.

But as an experienced and interested (and, I hope: competent) DIY'er, I would be inclined to experiment with the crossover and drivers anyway - if only to satisfy my own curiosity about the waveguide principle. I have played around with 2-way horn constructions a long time, and - appearently like many others - am intrugued by a design that has been a major theme on many DIY-forums for a long time.

I have a lot of units lying about. I will certainly try the waveguides and play around with a number of drivers and bass units.

Earl: my question was not so much about the crossover network itself, as it was about matching the polar response of various size bass units to the polar response to the waveguide. How critical is woofer size compared to the acutal 10-inch waveguide size?
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Old 15th May 2008, 06:44 PM   #135
gedlee is offline gedlee  United States
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Quote:
Originally posted by LAL
Earl,
This last post about crossover construction is why I earlier suggested that you only offer completed crossovers with your kits. People subsequently listening to completed kits cannot tell that the heart of the design-the crossover-has been modified from the original, and for better or worse will believe it to be your work. A poorly done modification will only have negative effects on the public perception of your work.
LAL
Understood, but wiring the crossover is one of the most time consuming parts and my doing it would drive up the price substantially. I just don't see it as an option.

Quote:
Originally posted by EspenE



In a sense, I agree on that. I'm sure that Earl's crossover and the chosen units is the best for his design. No disagreement on that. And I intend to build it just as specified.

Earl: my question was not so much about the crossover network itself, as it was about matching the polar response of various size bass units to the polar response to the waveguide. How critical is woofer size compared to the acutal 10-inch waveguide size?
The waveguide size has more to do with how well it works than the crossover point. A 10" one does not control as well as the 12" which is not as good as the 15". Ideally it should be about 18" - I could make that size work perfectly. The 10" has a lot of flaws, but the size is attractive to most people.

The woofer size determines the frequency at which the two source patterns mate up. As you would expect the 10" woofer mates to the 90 output of the waveguide at a higher frequency than the 12" and 15". The 15" is about 800-900 Hz the 12 about 1 kHz and the 10 about 1500 Hz.

From my data, the ideal would be an 18" waveguide with a 12" woofer. This would elliminate all the flaws that I see in practice. But such a combination would not be an attactive speaker for a lot of reasons. the next best, and what I would build for myself, is a 12" woofer and a 15" waveguide. Simulations indicate this combination to be a very good match.
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Old 15th May 2008, 06:57 PM   #136
Salas is online now Salas  Greece
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Quote:
Originally posted by gedlee
From my data, the ideal would be an 18" waveguide with a 12" woofer. This would elliminate all the flaws that I see in practice. But such a combination would not be an attactive speaker for a lot of reasons. the next best, and what I would build for myself, is a 12" woofer and a 15" waveguide. Simulations indicate this combination to be a very good match.
You can still make a 3 way with an 18 inch woofer, 12 inch mid woofer and 18 inch WG, if some large club lends itself for a set of custom floor speakers job. Marketing such, is up to your pro installation circle of people.
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Old 15th May 2008, 07:20 PM   #137
gedlee is offline gedlee  United States
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Quote:
Originally posted by salas


You can still make a 3 way with an 18 inch woofer, 12 inch mid woofer and 18 inch WG, if some large club lends itself for a set of custom floor speakers job. Marketing such, is up to your pro installation circle of people.

Everything always comes back to the "marketing". I've decided to try making small kits and see how that works. If it doesn't, then I doubt that I will do anything else.

As cost goes up you sell less, as size goes up you sell less, if low cost small size does not sell then where's the market?
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Old 15th May 2008, 07:37 PM   #138
Salas is online now Salas  Greece
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Quote:
Originally posted by gedlee



Everything always comes back to the "marketing". I've decided to try making small kits and see how that works. If it doesn't, then I doubt that I will do anything else.

As cost goes up you sell less, as size goes up you sell less, if low cost small size does not sell then where's the market?
The market is set by the pro network decades ago. You look for niche markets. Some kit here, a custom installation there even with some expensive one off speakers. Find small installers that they need to boast quality and difference, and can import your speakers starting a small trend in up coming markets like Russia etc.

Visit Pro light and sound next spring with your speakers and papers and nice brochures, and talk to people there. Some installers in Europe have customers in Classical and Jazz music that look for excellence and new things...

In Thailand they just need beautiful ladies around the pole, not quality sound. Dirty SPL and a known badge on the plastic box is ok when the farangs use their eyes and not their ears.
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Old 15th May 2008, 07:53 PM   #139
gedlee is offline gedlee  United States
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Quote:
Originally posted by salas


The market is set by the pro network decades ago. You look for niche markets. Some kit here, a custom installation there even with some expensive one off speakers. Find small installers that they need to boast quality and difference, and can import your speakers starting a small trend in up coming markets like Russia etc.

Visit Pro light and sound next spring with your speakers and papers and nice brochures, and talk to people there. Some installers in Europe have customers in Classical and Jazz music that look for excellence and new things...

In Thailand they just need beautiful ladies around the pole, not quality sound. Dirty SPL and a known badge on the plastic box is ok when the farangs use their eyes and not their ears.
I agree for the most part, but going to shows and selling in Russia are just not things that I can do. I'm a scientist, not a salesman.

I can tell that you have been to Bangkok before. Some of those places made my eyes bulge, my ears hurt and my mouth water.
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Old 15th May 2008, 08:16 PM   #140
SunRa is offline SunRa  Romania
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Quote:
From my data, the ideal would be an 18" waveguide with a 12" woofer. This would elliminate all the flaws that I see in practice.

Dr. Geddes,


could you please develop this affirmation a little? Why a 18" waveguide would have a better polar response control?

And how would the lenght of the waveguide affect the top end frequencies compared with the smaller waveguides?


Thank you!
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