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In the Forum: Horn-Loaded Speakers
In the Thread: Jessie Dazzle Project
Post Subject: Images & some answers 45Hz hornsPosted by jessie.dazzle on: 8/4/2008
Romy wrote :
"...Jeffrey Jackson suggested that to build the horn similar that he has built for the GOTO distributer he would charge around $15K. As I understand you are a software engineer, so with $100/per billable hour of your salary the $15K is just a little bit more than a month of work. Do you think it worth to consider?
I do my best to remain ignorant of the price for which I sell off the hours of my life. (Btw, I'm not a software engineer; I design cars). Yes I could pay someone to do the work, but I'd rather put the cash toward the purchase of a good room.
There's more to it... It will sound backwards, but the truth is that I am just too lazy to have anyone else do it.
"...Also, you are in Europe and get paid in Euros and you can always found a builder to who you will hay lea - in countries with their economic: China, Russia, India, USA, Mozambique, Mexica, Taiwan etc…"
I have a contact in Turkey that is fully capable of doing it. And another in Mexico that might be capable. I will call on them the day I start up a company to "mass-produce" mid-bass horns.
Regarding throat diameter:
"...You will have too large front chamber. It will give you more gain but no one knows what else it does with sound. Generally for 7” hole I would like to see 10” driver… but I do not know any 10 incher of good sound. The LF section of Tannoy Red or Silver would do but they have 100dB less sensitivity then necessary…. I would look more or perhaps try to use the Vitavox 15” and to see what happen… Thankfully you will have so much aggravations with your horn that the driver size will be the least of them…"
I still might revise the design for an 8-inch throat.
However...
A 7-inch throat diameter works out to just under 65% of the diameter of the cone (minus the suspension) of an AK151.
65% is also the ratio of throat to cone (minus the suspension) in the case of the Fane driver when installed in the 115 Hz horn (4-inch throat); this horn works well.
It may be incorrect to assume that the same 65% ratio will give equally good results in the case of a larger horn.
Above : Inner surface of horn with driver
Above : Side view to show scale, shown here with bolt flanges and rear chamber
(overall length is 3.05m)
Above : Both horns with bolt flanges and rear chambers. Horn wall thickness and stiffening ribs are not represented in any of these images, because I am still working it out.
Above : This is the setup that I will try first... Large horns firing from behind listener. I'm not at all sure it will work. Only one way to find out...
The large horns will be filtered to play up to around 240Hz, 1st order. This means the point of origin of the sound will be identifiable as "coming from behind"... However, I'm hoping the 115Hz upper-bass horns will re-establish the bass image and pull it back around to the front.
If it doesn't work I have two other options:
1) Set horns to fire all in same direction (will require some modification to the house)
2) Move to a new house
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