The Big Littlehorn ? ...FE83En

[Bigun]

Big in sound, little in size (kind of dooms the idea of a horn doesn't it)

I'd like to have a go at some desktop speakers for a flea-power tube amp. I'd like something narrow (hence FE83En) to go either side of a wide LCD monitor and no taller than a typical monitor. Fostex recommens a "small BR or a BLH" for this driver. I think I can handle a design for a BR and I should probably build one of these....

but I fancy a horn and I don't know how to design a BLH option. I don't have design software or the experience to use it.

I'm looking for a short-cut, if there is one.
For inspiration I went to these places:

1/ Backloaded Horn for Fostex FE 83
The Buschorn looks like one option, although it's taller than I want.
The Naga-Micro also looks too large.

2/ SpeakerBuilding.com - The High Fidelity Voights, Page 1
This Danish High Fidelity Voigt looks interesting. It's based on a larger driver but maybe a good starting point. It's about same height as the Buschorn. It's also not looking like a mass-loaded port like most Voigt Pipe's but more of a horn-fare loading? Which is a good lead-in to the latest option,

3/ Frugel-Horn Mk3
Frugal-Horn (FH3) with it's attractive 'Ron Clarke' curved back. I don't want to go off-topic in that thread so I've stared this one...

Since I can't model this kind of thing I have to wing-it by treating it like a folded Voigt Pipe.

The FE83 has a high Fs of 165Hz. How low should I tune a Voigt Pipe, can I get away with 120Hz ? - means a pipe length of 0.7m and I'll pick a mouth size of 1.5 x Sd for no good reason (this mouth will be the low pass filter to the horn flare too). I'll avoid a pointed end as I've read that this is bad for 'ripple' so I'll close it off with an area of about = Sd.

p.s. Scottmoose already warned me this idea is a little wild, and given I'm no speaker designer maybe I need to give up on this one here and now and save myself a lot of grief ?

[planet10]

Originally Posted by Bigun

It's based on a larger driver but maybe a good starting point... It's also not looking like a mass-loaded port like most Voigt Pipes

Mass Loaded voigts are actually a fairly new phenomenom, althou sometimes seen in the past, Martin Kings ML-TQWT article laid down the quantitative framework for taking advantage.

Most traditional voigts have no mass loading and typically suffer from large amounts of ripple.

dave

[Scottmoose]

Desktop & horn, esp. a rearward firing one, is basically a duff combination. The 83 isn't thrilled at being tuned much below its Fs, there's no time for proper integration, nor sufficient space between them & you also say you've a monitor etc. in the way hashing things up still further. The results are likely to be a complete mess, above all as you're not sure what you're doing. Sorry, but I'd rather say that now & possibly save you from wasting your time & money than say 'go ahead' while knowing the results you get are likely to be poor.

[Bigun]

So, the issue is that I'll have the sound from the front of the cone arriving pretty quickly and the sound from the horn mouth arriving much later, with the monitor being stuck in the way. Hmmm. Well at least now I 'get it' and it makes sense to me. Darn it. But thank you !!

So I am learning that for near field monitors I want to have all the sound coming out from the front of the enclosure. This keeps the path length of the sound to my ears roughly the same and keeps it away from the back of the monitor.

Last question on horns then - is a Front facing horn possible ? perhaps a BVR, something to give me a bit of gain at low frequencies where small drivers are poor ?

[Scottmoose]

Partly, but the result is similar.

Nearfield monitors are best sealed, aperiodic, TL or vented IMO. Not necessarily the most exciting, but nearfield monitors aren't really the best type of enclosure for experimenting with some of the more extreme forms of cabinet load. You're too close, & the boxes & space is too small, so direct radiation & as near to point-source as possible is what's needed.

The 83 doesn't do quality bass (let alone achieve a reasonable dynamic BW) in anything other than a full sized horn.

[chrisb]

Originally Posted by Scottmoose

Partly, but the result is similar.

Nearfield monitors are best sealed, aperiodic, TL or vented IMO. Not necessarily the most exciting, but nearfield monitors aren't really the best type of enclosure for experimenting with some of the more extreme forms of cabinet load. You're too close, & the boxes & space is too small, so direct radiation & as near to point-source as possible is what's needed.

The 83 doesn't do quality bass (let alone achieve a reasonable dynamic BW) in anything other than a full sized horn.

However, the late lamented FF85K in a small aperiodic enclosure is silly good, from near to moderate listening distance (of course in larger spaces, bass augmentation is required)

[Bigun]

Hmm, perhaps the Henkjan TL box originally designed for the Alpair5 is something I should look at - some of the key driver specs aren't so different from the FE83En.

Yes, the demise of the FF85K isn't so good.

You know, I've only really made one set of DIY speakers which allowed me to hear the Fostex 127's and apart from the 7kHz peakiness I like them very much. It makes me nervous to consider something other than a Fostex - in this case the FE83En.

There are some less expensive 3" drivers available, but I've no idea about their pedigree ?

3" paper cone from Hi-Vi:
https://www.madisound.com/store/prod...oducts_id=8831

3" Al cone from Peerless:
https://www.madisound.com/store/manuals/830987.pdf

3" from Fountek:
https://www.madisound.com/store/manuals/fr88ex.pdf

[Scottmoose]

Hmm, perhaps the Henkjan TL box originally designed for the Alpair5 is something I should look at - some of the key driver specs aren't so different from the FE83En.

...the difference being that the A5 can be tuned rather lower. It's still not a good idea to take it too low, but it's happier than the Fostex. TBH, I'm not a fan of the 83, unless it's high-passed with supporting woofers.

[Ty_Bower]

Originally Posted by Bigun

I'd like to have a go at some desktop speakers for a flea-power tube amp. I'd like something narrow (hence FE83En)...

...The Buschorn looks like one option, although it's taller than I want.

I built a Buschhorn (mk.I, the original version) and I am consistently amazed by its performance. The output seems to defy what should be possible from the 3" FF85K in it. As you note, it is quite a bit too tall to set on your desk next to the flat panel display. I think Dave described it as a "tiny floorstander".

I also built a set of Makizou M-8BH clones. They are quite a bit shorter than the Buschhorn, and the mouth exits from the front of the enclosure. These might suit you better? I installed a pair of FE87e in mine. They don't perform as well as the Buschhorn, but I do think they sound good. I'm pretty sure I heard something special when I listened to them for a while, and that partly drove me to build the larger Buschhorns. You will find a lot of my notes about the Makizou in this thread:

Makizou, I finally did it.

[chlorofille]

Hi Bigun,

for nearfield listening, I recommend the Vifa 3.5'' fullrange fibreglass cone.

It has a rising response from 1000Hz to 200Hz which sort of acts as a baffle step compensator. I have them in a 4L vented enclosure which boosts the low end by 3dB to make nearfield bass acceptable. I run them direct without any filters and they somehow sound full and rich.