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Old 22nd August 2012, 02:24 AM   #1
Persona is offline Persona  United States
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Default Smaller Fostex Backloaded Horns

I am intrigued by the full range driver concept and I'm looking to build a pair of cabinets for myself. In my research I have found the Fostex line of drivers to be very well regarded and I have looked at a numerous designs for a few of these drivers.

Of these, the Dallas II and Jericho horns really caught my eye, however I am put off by the very large size of these cabinets. My room is about 16x16 feet and because I move frequently I'd rather not have to lug such heavy cabinets up and down stairs!

Therefore, I'm looking for similar cabinets that are smaller and/or designed to make use of smaller drivers. So far the only one I've come across is the Fostex FE208Sigma in Folded Horn Enclosure, but the plans are no longer available and I can't find any information on its performance. Other designs I've seen are either not true horns or are rather ugly. If someone could point me in the right direction I'd really appreciate it!
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Old 22nd August 2012, 05:27 AM   #2
mp9 is offline mp9  United States
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Recommended Enlosures | Fostex

at 16'x16' you should know from the start square rooms are difficult, i.e., standing waves...would behoove you to look into room treatment options too.

Madisound Speaker Store - the fostex designed horn plan is small, i haven't read of any builds so can't tell you how the horn sounds. From what i've been able to make out from japanese forums the drivers are good.

Madisound Speaker Store

Woden Design | Fostex - these are very good. I can recommend the Victor only it needs breathing room/10' listening distance from the baffle and is large for your space.

The Spawn Family of Double Horns - the Congo may work for you but again requires a 10' distance.

Hope this helps.
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Old 22nd August 2012, 06:29 AM   #3
chrisb is online now chrisb  Canada
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16x16 ft isn't a huge room and the dimensions are a bit unfortunate, but what'd'ya gonna do?

at $282 a piece and considering the enclosures required to elicit their best performance, if this is your first BLH, you might want to consider a smaller model of driver


FH3 +126 = great performing, compact & easy to move
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Old 22nd August 2012, 06:36 AM   #4
Persona is offline Persona  United States
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I'm definitely open to smaller drivers—different brands even. I'm not set on the Fostex 208 or any other driver really (especially the sigma, which as you pointed out is rather expensive). The cabinet I linked to was just a good example of what I've been considering.

The Frugal Horn looks pretty interesting. Very simple and good looking too! I'll definitely add it to my list.
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Old 22nd August 2012, 10:21 AM   #5
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Quote:
Originally Posted by Persona View Post
I am intrigued by the full range driver concept and I'm looking to build a pair of cabinets for myself. In my research I have found the Fostex line of drivers to be very well regarded and I have looked at a numerous designs for a few of these drivers.

Of these, the Dallas II and Jericho horns really caught my eye, however I am put off by the very large size of these cabinets. My room is about 16x16 feet and because I move frequently I'd rather not have to lug such heavy cabinets up and down stairs!
Believe me, as back-horns go, the Jericho and Dallas II (which was designed to address the shortcomings of the Jericho) are not large.

Hoffman's iron law. You can have any two of these, but the laws of physics mean you can't have all three while maintaining some semblence of a linear response (curses): small size, high efficiency, low bass. Back-horns are almost invariably the bulkiest of all box types for a given tuning frequency. So if small is a priority & you're after deep bass extension, you might want to consider another enclosure type.


Quote:
Therefore, I'm looking for similar cabinets that are smaller and/or designed to make use of smaller drivers. So far the only one I've come across is the Fostex FE208Sigma in Folded Horn Enclosure, but the plans are no longer available and I can't find any information on its performance.
That's the old Fostex BK201. See attached. It was fairly popular around the turn of the century, although I suspect that was more due to a lack of easily available alternatives than anything else. Frankly, it's not great. OK-ish, but there are other designs that will give (substantially) superior performance now.


Quote:
Other designs I've seen are either not true horns or are rather ugly. If someone could point me in the right direction I'd really appreciate it!
Depends what you call a 'true horn.' I wouldn't get too worked up about that concept, because frankly, it doesn't mean a whole lot. Pick a popular horn plan. 90% of the time, we'll be able to tell you why it can't be called a 'true horn' because it doesn't meet xyz criteria. So if you want some advice, forget nebulous ideas of what is and is not a horn, and concentrate on what really matters, i.e. how well the cabinet achieves its design goals, and whether those match your requirements. Depressingly practical, but it'll get you where you want to be faster than worrying about definitions will.

If you want a compact horn that's easy to move around, FH3 is worth looking at. For larger drivers, you're going to need a bigger box I'm afraid. So, it depends on what compromises you're willing to make.
Attached Images
File Type: jpg Bk2011.jpg (23.4 KB, 864 views)
File Type: jpg Bk2012.jpg (33.2 KB, 842 views)

Last edited by Scottmoose; 22nd August 2012 at 10:27 AM.
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Old 22nd August 2012, 11:57 AM   #6
DrBoar is offline DrBoar  Sweden
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I would go for a new horn by a very experienced designer
Horn Theory
" A Method for Designing a Compact Back Loaded Horn Loudspeaker System (added 06/21/12)" It is less than half the size of Jericho and gets as deep as it, when corner loaded that is.
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Old 22nd August 2012, 12:08 PM   #7
hm is online now hm  Europe
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Default small horns

Hello,

look my HP,
different satellite horns down 100 Hz and need a sub,
or my double horns, Saxophon, Posaune XL, RDH20,
measurements, feedback, plans.
Attached Images
File Type: jpg posaune-mit-fostex-206e-006_55470.jpg (9.8 KB, 824 views)
File Type: jpg saxophon nirvana.jpg (64.7 KB, 817 views)
File Type: jpg 2alphornhornsat.jpg (262.3 KB, 816 views)
File Type: jpg alphorn schalmeihinterg.jpg (110.7 KB, 129 views)
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Old 22nd August 2012, 12:53 PM   #8
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Quote:
Originally Posted by DrBoar View Post
I would go for a new horn by a very experienced designer
Horn Theory
" A Method for Designing a Compact Back Loaded Horn Loudspeaker System (added 06/21/12)" It is less than half the size of Jericho and gets as deep as it, when corner loaded that is.
Ha! I'm a member of Martin's QW group, but I never seem to get chance to visit these days, so first I'd heard of this.

Looks to be a nice little box. I've played with internal Helmholtz absorbers in the past, although generally for untapered QW pipes rather than horns (not that that changes the principle). That was actually one of the ideas I was kicking around for FH3 in the initial concept stages, but eventually we went with the current configuration since minimal parts count & no unused volume (which would have otherwise resulted) were priorities. They've started to become a little more popular of late -for a while, a couple of German TLs notwithstanding, Onur's Singular was about the only box I can think of that employed them, but Tony Gee's used one in his latest BR (albeit more for the sake of being different than any genuine benefit IMO) & there are a couple of others lurking on the fringes too.
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Old 22nd August 2012, 05:00 PM   #9
DrBoar is offline DrBoar  Sweden
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The Jericho 08 also has a internal Helmholtz absorber, while the original Jericho did not.
The Jericho 08 is also unusal in that driver is crammed into the horn throat directly, instead of housing it in a lowpass acting chamber.

Have you ever used piano hinges to mount "doors" covering the horn opening when not in use and then folded out when used to act as horn extensions/baffles? The danish designer Duelund did this in the 70s.
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Old 22nd August 2012, 06:10 PM   #10
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Quote:
Originally Posted by DrBoar View Post
The Jericho 08 also has a internal Helmholtz absorber, while the original Jericho did not.
The Jericho 08 is also unusal in that driver is crammed into the horn throat directly, instead of housing it in a lowpass acting chamber.
Good point, yes, I forgot about the most recent Jericho design. AJ Horn has had the facility to model internal Helmholtz in the last couple of itterations, albeit with some restrictions on where it can be placed (AFAIK). I'm not too keen on these particular chamberless designs, Helmholtz or otherwise, given the proximity of the driver to the internal wall behind it. That usually spells problems with early reflections.
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