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Old 12th November 2012, 08:21 PM   #1
castorG is offline castorG  Italy
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Default Designing a blh for lowther dx3

Hi everyone, I need help to design a horn for this driver. The problem is that I have no idea how to do it. I've done a design that fits my space and I think it is well done since it is enough long (320-350cm long) and has a big mouth (74x28-30cm). But I absolutely have no idea if it is a good one or not. Mine, afterall, is just an idea of how I would like it to look. So I need your help..

My idea is to get it down to 50hz (better if lower, but I know that with lowther and a relatively small enclosure it is impossible).

As you see, I'm thinking on using 2 baffles, trying to get a little more space for the compression chamber without making the cabinet too big and heavy (from a beauty point of view, not weight).
Of course measures are not perfect, starting from the compression chamber, but it is just an idea for know. When designing it my first thought was to make it as simple as possible, with the less bends possible and trying to guarantee a good length and a big mouth, given the external limitis.

It is tall 132cm and maximum deep is 55cm. I still must decide how large to make it. The center of the driver is at 98cm.
Horn lenght: 320 cm. It can be brought to circa 345cm by making it 137cm tall. I don't know what lenght is best.
Width:28 or 30 without counting the lateral pannels..suggest me.
Mouth: 74x28-30.
Compression chamber: I recall from somewhere that the right volume for the dx3 is 3.1l (maybe from the hedlund horn). But I'd like to make it adjustable someway..maybe someone else will want to use a dx2 or dx4.

Can anybody simulate it? I'm a disaster in math and in computer programms..I can't even make hornresp work.

Please help me..lowthers are really good drivers, but what they miss are good cabinets. I think they deserve better.
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Last edited by castorG; 12th November 2012 at 08:37 PM.
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Old 13th November 2012, 09:44 AM   #2
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In my opinion you should first calculate the horn form and then adjust the panels in your plan to approximate the horn. First making something horn-like (from a visual point of view) will likely not give the best result.
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Old 13th November 2012, 10:57 AM   #3
castorG is offline castorG  Italy
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The problem is that I don't know how to do it.. I'm not able in running hornresp or other horn programs.. Could someone please do it? Trying to use the datas I gave (mouth, horn length, compression chamber, width and the beginning of the horn being 3cm wide from a side point of view). If my datas are not enough, please ask.

Ervin
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Old 13th November 2012, 02:54 PM   #4
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Well, not a direct answer to your questions, but I just want to point to Andreas Mau's "Signature Two" speaker that looks a bit like what you have in mind, and it is a proven and (if I am not mistaken) respected design, check it out here:

Signature Two
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Old 13th November 2012, 06:33 PM   #5
GM is offline GM  United States
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Greets!

You are basically wanting someone to re-invent the wheel in a different tread pattern, so all things considered, rearranging the folding of a proven design has a better chance of performing well.

Note that for the theoretically best performance, changing the filter chamber volume [net Vb] requires a different throat area, horn expansion, so best overall to use one of the 'one size fits all' Lowther designs.

GM
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Old 14th November 2012, 06:44 PM   #6
zobsky is offline zobsky  India
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Quote:
Originally Posted by castorG View Post
Hi everyone, I need help to design a horn for this driver. The problem is that I have no idea how to do it. I've done a design that fits my space and I think it is well done since it is enough long (320-350cm long) and has a big mouth (74x28-30cm). But I absolutely have no idea if it is a good one or not. Mine, afterall, is just an idea of how I would like it to look. So I need your help..

My idea is to get it down to 50hz (better if lower, but I know that with lowther and a relatively small enclosure it is impossible).

As you see, I'm thinking on using 2 baffles, trying to get a little more space for the compression chamber without making the cabinet too big and heavy (from a beauty point of view, not weight).
Of course measures are not perfect, starting from the compression chamber, but it is just an idea for know. When designing it my first thought was to make it as simple as possible, with the less bends possible and trying to guarantee a good length and a big mouth, given the external limitis.

It is tall 132cm and maximum deep is 55cm. I still must decide how large to make it. The center of the driver is at 98cm.
Horn lenght: 320 cm. It can be brought to circa 345cm by making it 137cm tall. I don't know what lenght is best.
Width:28 or 30 without counting the lateral pannels..suggest me.
Mouth: 74x28-30.
Compression chamber: I recall from somewhere that the right volume for the dx3 is 3.1l (maybe from the hedlund horn). But I'd like to make it adjustable someway..maybe someone else will want to use a dx2 or dx4.

Can anybody simulate it? I'm a disaster in math and in computer programms..I can't even make hornresp work.

Please help me..lowthers are really good drivers, but what they miss are good cabinets. I think they deserve better.
You could try designing from the first principles, and then playing around with hornresp (folks here can help)
bigfunht
The "ALL Fun" Horn
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Old 15th November 2012, 04:46 PM   #7
Bare is offline Bare  Canada
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Quote:
Originally Posted by castorG View Post
Please help me..lowthers are really good drivers, but what they miss are good cabinets. I think they deserve better.
Actually they are Not.
Despite All bleatings to the contrary.
Just as many swear at them as by them.
But hey! spend the next couple of years exploring that for yourself.. I did..
Although Nelson Pass's Lowther horns do have seductive appeal, intriguing even.. IF one lives in an auditorium.
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Old 15th November 2012, 08:34 PM   #8
castorG is offline castorG  Italy
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http://www.quarter-wave.com/Horns/BL...gn_Article.pdf

This new pdf is a really good one!
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