FE168ESigma BLH recommendations please

[Rafal]

Hi Everyone,

I want to build a set of spectacular BLH horns. I'm looking at fostex FE168ES driver as my choice (I think it will be the optimal driver considering sound quality (midrange), price and extension (please correct me if I'm wrong and if I should look at different driver instead - my budget for drivers is about $500 CAD). I have read a lot of comments about suggested enclosures and some conidered ones are:
BIB
Spawn family
Ron's modified A166
Nagaoka D37
Fostex recommended BLH

Out of these boxes, which would you recommend? I really want to achieve the flattest response possible and don't want to resort to using any filters or a tweeder. Appearence wise, they would all look cool. I would also preffer to go with most evolved and proven design.

To put things in perspectve, I have tried OB with FR125S and B200. I have also built BIB with Dave's modified FE126E and I preffer them over OBs. Even thoug the FE126E BIBs are spectacular, I have gotten a taste of a BLH and want to substentially improve on the idea.

Please help.

Rafal

I anxiously await your suggestions.

[Scottmoose]

Oddly enough, I'm working on a double horn (long path) specifically for the 168ESigma at the moment, which should be 'interesting' once it's done.

If you want a simple box, then the BIB is about as simple as it gets, and this, with a Sigma, is a lethal combination. Bit more ripple than some of course, but that's the nature of the beast.

Ron's Austin is probably the most advanced BLH on the planet in terms of the detailed modelling & modified to suit the Sig. could be very special. The Factory and Nagaoka designs aren't bad, but aren't of the same standard IMO.

Hope that's of some use
Scott

[Rafal]

Tanks Scottmoose,

Do you know what modifications are required to Ron's Austin to optimally work with FE186ES?

I'm also interested in your double horn for Fe168es. Can you let me know once you have it done?

Thanks,

Rafal

[hm]

Hello,
for this driver the TUBA would be an alternative.

[mp9]

How about with the 166es-r's ? Do you happen to know the ideal c.c. size for the austin's with 166es-r (they're on the top of my to build list) ? What do you think of the 166es-r's in the double horn you're working on and any guesses on how that combo would compare to the austin's ? Is the driver in your double horn mounted in a (radial , exponential or other) front loaded horn along with a (back , front or side ) horn loaded cab. for bass reenforcement ? Would the fostex 166es-r's be to flat of a driver for that type of design ? I'm very interested in seeing the preliminary plans . thanks in advance for keeping this hobby (obsession) interesting .

[Scottmoose]

Ron's the man to ask about the CC of his Austin -they're hyper refined designs, and it's not my place to suggest adjustments to them. FWIW, Leach indicates a Vb of 2.67 litres, not including the driver, but the approach is somewhat different.

The ES-Rs are very much niche products, with very differenct specs. to the Sigmas, so they aren't / won't be a stright swap. They should go into Hiro though. I've only just started this 168 design, so it might take a little while to get the design finalised -it's constant expansion this time around, not stepped, which complicates matters a trifle. It's a pure (double) BLH though, rather than a compound design (no front horn).

Flat to? As in, how low will they go? Well, 40Hz is the target. I'll keep you guys posted on how we're progressing.

[hm]

Hello, the 206ES-R is a big thing,
I think the 166 ESR is to big, over powered,
its difficult to find the balance to the mids.

Such a speaker can load a horn up to
400 Hz, this might be good SPL, but bad sound.

The Posaune needs only an FE166E+FE167AV invers
cheaper than one sigma Fostex, gets more than
a 1 driver horn ever get, and smaller enclosure.
250 Hz is the end of my basshorns.

I have not seen any measurements of Austin ...
so I can´t say anything.

All my horns are exponential.

Thanks

[ronc]

think the 166 ESR is to big, over powered,
its difficult to find the balance to the mids.

Nonsense! you can control any part of a sound spectrum if designed correctly.

have not seen any measurements of Austin ...
so I can´t say anything

Seanzozo posted his in-room response.

All my horns are exponential.

Why? a given driver T/S parameters sometimes needs a different flare rate and sometimes needs a combo of up to four to get a balanced FR.

To calculate the different driver i need the following info:
1:Sd
2: Vas
3:FR curve(IB)
4: Qts
5: Qms

ron

[Scottmoose]

I'm with you on those Ron. Surely a cabinet should be designed with the characteristics of the driver in mind? Seems a bit daft not to, unless it's deliberately intended to be a generic cabinet to work with a few different drivers?

I can't see a problem with a driver / horn working to 400Hz either if it's accounted for in the design come to that. In fact, several advantages spring to mind: compensation for baffle-step drop-off to cite but one example. Besides, as GM pointed out to be (& a lesson I've taken to heart for BLHs) better to have too much gain than too little -you can always damp down what you don't need. Not so easy to boost what you don't have enough of in the first place.

Most of the BLHs I've been modelling recently have been hyperbolic or a variation on one of those flares. I haven't got quite to Ron's hyper advanced stage of different flare-sections yet (Austin's final section is conical if I remember rightly Ron?) although Dave & I have made a start -two of the BVRs (Loreena and Oscar, for the Lyeco 801 and Visaton 200 respectively) have a parabolic mid-section to the flare (or a variation of). Works better than pure exponential in this application anyway, or seems to according to MathCad.

[ronc]

Austin's final section is conical if I remember rightly Ron?) although Dave & I have made a star

Sure is! This is what i simmed on my waveform program. If the final stage is conical the wave returns to its proper shape(spherical).It dosent totally(gets near though) correct for the earlier flare rates , but it does help a great deal. Add the curve for the aspect ratio and presto you have a very near natural spherical wave.Factor in the TL action and Bobs your uncle (as they say across the big pond).
What you do to the wavefront as it begins (the throat) the effect is carried all along the sound/pressure path. However it lessens its effect as it traveles along the expansion path. Any deformed wave produced will, over time and distance, try to return back to a spherical wavefront.

In my early years i ran many tests using IR192 (a radioactive material used in industry) to evaluate various collimators. These collimators were designed as a safety method to reduce the amount of radiation to the operators. With a retangular slit as the port i kept seeing a gradual return to a circular response as distsance increased. The pattern naturally had a higher density at the center, but the slit shape ,over distance, started returning to circular. Some of this early work was incorporated (in some applications) to in-motion radiography in which pipe weld long seams were x-rayed while moving.

ron