Onur's double horn - a solid design?

[hugz]

I'm getting closer to constructing my first pair of speakers. My FE206Es arrived a little while ago, but due to uni obligations I've yet to have time to build a cabinet for them. In the meantime, they've been burning in in an approximate open baffle. They sound okay, but not great.

The design which has captured my attention the most is Onur's double horn. The only problem is that it's relatively untested compared to other designs.

I personally have no skill in horn design, so I was wondering if more talented members could tell me if Onur's double horn looks like a design which should work well

The design can be found here:
http://www.yildiz.edu.tr/~ilkorur/sp...tex_fe206e.htm

Thankyou

(also if anyone has any first hand experience with this design i'd LOVE to hear it)

[planet10]

hmmm.... Marco likes them better with 207 (and i just bought a pair of those)

Onur has been doing some innovative work, i know Moray had some good things to say about some of his designs that he tried.

dave

[Scottmoose]

It works. I checked a few months back in MathCad. It's really a sort of Replikon with a couple of mouths. Technically, it's more a TL, or big-vent reflex, as Martin or GM would say, than a true 'horn' -it's none the worse for that though. Most are, until you get to Kleinhorn size. These hybrid TLs / BR designs with short, rapidly flaring vents do seem to work very well in some cases. As Dave advises, I'd stick with the 207. 1/2 space response graph generated in MathCad below.

Best
Scott

[hugz]

Well... i dont have FE207Es! Does this enclosure seem unsuited to the FE206E then? Maybe i should use the dallas II instead? I like the look of Onur's design, but if it's just a fancy BR then i suppose it WOULD be more suited to FE207E (as i understand, fostexs ending in "6" are suited to horns whereas ones ending in "7" are suited for BRs)

[Scottmoose]

Not at all. Just add a touch of series resistance to the 206 and you'll be in business. You can either do it via a resistor, or a highish resistance cable. Magnet wire is ideal -24AWG or similar. If you want 'proper' hifi cable, then Van Den Hul's carbon wire will be just the ticket.

[Ron E]

I would redesign such that the front were flush, or put absorbing material on the baffle projections. Early reflections are bad for fidelity. I suppose the time and image smear caused by these early reflections will be diminished by the beaming fullrange, but it exists nonetheless.

There is a certain class of DIYers that like formulaic designs. I say not designing your own enclosure takes all he fun out of it. Designing an enclosure requires a chain of decisions, why would you accept someone else's?

[hugz]

Originally posted by Scottmoose
Not at all. Just add a touch of series resistance to the 206 and you'll be in business. You can either do it via a resistor, or a highish resistance cable. Magnet wire is ideal -24AWG or similar. If you want 'proper' hifi cable, then Van Den Hul's carbon wire will be just the ticket.

Hm I don't think i'd be happy with that. Although it's silly, lately i've fallen for the idea of having a horn. I wouldn't be happy knowing that all I have is a fancy BR. No matter how nice it sounds, this would bug me. Silly I know, but I'm silly.

For the horn fans.. yes i do hope to make a front horn sometime in the future! A rear horn is just my introduction to horns

Originally posted by Ron E
There is a certain class of DIYers that like formulaic designs. I say not designing your own enclosure takes all he fun out of it. Designing an enclosure requires a chain of decisions, why would you accept someone else's?

I agree that designing your own is the ultimate, but at this stage I'm too newbie for this. I want to build someone else's design/s to get used to the building process, and then I will try to design my own. I have to learn a lot about horn design before I can even start to think about designing my own. In the meantime, my fe206e needs a cabinet!

Also, there's no real point in designing my own cabinet if i dont have anything to compare it against. If i build a cabinet of a well regarded designer, and then design my own, I will be able to compare the sound of my own design against theirs to see if mine is any good. Unfortunately at the moment I dont have any reference point, which is why I want to build a well regarded cabinet instead of taking a risk on a new one (like onur's which is relatively untested).. since i have no reference, i have no way of knowing if the fe206e is living up to it's potential in the cabinet

Thanks for your comments so far. Based on them, I think i will probably have to move away from onur's sexy design and build the Dallas II instead. Since i like onur's design so much, I may consider buying a pair of fe207e's after I build my dallas

[Scottmoose]

The Dallas II is also a hybrid.

It's basic physics really: to generate low frequencies, a horn has to have a huge mouth. Like this: http://www.passdiy.com/pdf/KleinHorn.pdf Note that despite their monster size, even these don't exactly pluge the depths: they go about as low as, say, the Dallas II or one of the Fostex Factory designs.

As most of us will never be in a position to have such a pair of monsters, all the full-range domestic back-loaded horn designs you will see, DIY or commercial, use some form of hybrid loading for the lowest frequencies. Fostex, for example, use a series of 1/2 wave resonators, each stage slightly wider than the last (so in the strict sense, they are never horns at all). Most others behave either like a reflex, or a TL, depending on the design methodology choses, and shift to horn loading higher up. There's nothing wrong with either approach -they work very well if properly implemented, so don't worry too much about that!

Hope this helps a bit
Scott

[lndm]

I think a useful rear loaded horn will negate the effect of baffle step diffraction. The frequencies involved seem ideal for this application, I think.

I also think that corner loading is worth looking at. You could build a relatively small enclosure that blends with the room corner and extends very low.

[Onur]

Originally posted by Ron E
I would redesign such that the front were flush, or put absorbing material on the baffle projections. Early reflections are bad for fidelity. I suppose the time and image smear caused by these early reflections will be diminished by the beaming fullrange, but it exists nonetheless.

I don't agree on this. I have designed some other enclosures, which I have managed the time alignment the same way as I did with the double horn and in all those cases, the stage became one of the strongest point. The others were the quality of midrange purity and the absence of shouting effect.

However, I think that these kind of enclosures, large rear chamber and hyperbolic or exponential horn combination form a pitfall for simulation software depending on T/S parameters. The low end response looks balanced and free of ripple. I think this is deceiving. The reason is, most designs I have examined by reverse engineering don't have a flat low end response. A rise in the 60 to 100 Hz region is common. Making it flat may cause listeners to feel less bass. I, on purpose, made a similar design for Coral Flat10s and built the rear chamber just %10 smaller then I have in my previous designs and this caused a rise in 50 Hz to 150 Hz region, which did the trick. Again, placing the speaker unit behind the radiation plane of the mouth improved the midrange purity and staging.

The enclosure will on my web page soon, with some pictures.

/Onur