Front loaded horn concepts

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Hi everyone,

I've just finished some CAD renderings for my current project so I thought I'd share them with you all (links to larger images coming soon). I've essentially designed something similar in operation to an Oris system, but paid attention to aesthetics (after-all a high-end speaker should have high-end looks?), and investigated the cost side of things to see what it'd be up against in the 'real-world'.

Anyway, I've already had some ideas to tweak the styling, so my finished prototype (which I make next semester at uni) might look a little different. If anyone has any cool ideas that I could add please suggest them to me!

The drivers I've modelled in the renderings are the Fostex FE206e (tweaked) as this is what I will be using (at least initially) and the Eminence Magnum 15LF which measures very well for what I want and looks rather neat with its cotton mesh dustcap. The bass enclosure is around 120L and sealed. The plate amp is a BK electronics BSPV300 and I've used some virtual WBT binding posts hehe. Incase anyone's interested I used PTC Pro/Engineer with the photolux (lightwave) plugin for rendering.

Cheers, Richard.
 

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Yow. :D Nice. I'll take mine in red, if you please. How are you going to lay up the horns? I was just on this subject myself, and I'm thinking about wrapping my form with carbon fiber roving. But then, I'm still in the conceptual stages at this point- haven't ruled out compression drivers just yet.
 
Hi Corvus,

Well I've made the mould for it (foam->modroc>plaster of paris>reface>polishing!) and will be laying up in fibreglass. I think I'll be cutting (or rather tearing to help blend edges) chop strand into segments rather like orange segments. After all the release agents and a few layers of gel coat these will go on with layup resin obviously.

Heres a recent picture of the mould - hopefully will lay up in the next few weeks however workshops are currently shut during intersemester period which is impeding my progress :redhot: ....
 

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Hi Neil,

Thanks very much for the compliment. I agree it would be neat to have a fully active speaker.... perhaps I could mention this as a possibility during my evaluation stages of the project at the end of the year, however what I initially set out to achieve was a SET friendly speaker without the poor or compromised bass often associated with high-eff designs - this is how I ended with this 'hybrid' speaker if you like, similar to an Oris.

Another focal point of my project was to come up with a high-eff design that would hold its own (styling wise) against other 'typical' high end speakers (the B&W 800's, Linn Artikulats of the world). I felt that other than size obviously, although well designed acoustically, the aesthetics of the very limited numbers of commercial high-eff speakers currently availible probably has played a large roll in them not becoming more accepted.
 
Corvus, you are probably right if this project was about market share. It strikes me given the nature of the design and the painstaking attention to detail that rabw has lavished (at least on the VR version) on this project that it attempts to be questioning some standard concepts that prevail market share audio. I am not necessarily arguing with your point as its probably true, it just when manufactures like Avantgarde Acoustic release a product like their Solo that one stops and perhaps questions market share…;)
 
The Solos are a unique product. Unfortunate, though, the only reason I shied away from them was the fact I couldn't use my own amplifiers with them. I can have any tube amplifier I wish- I need only fire up the CNC, and go to work. Two weeks later-<ding!> world class Amplifier. The only things I can't build for myself (audio) or haven't bothered/ had success, etc., are source components, and speakers. By and large, I find the Avantgardes hugely overpriced, and getting worse. I was kind of hoping the Solos would allow me to finally have a commercial horn speaker that looked good and didn't break the bank, but without using my own amps, what's the point? I mean, I'm in the business of building amps, how am I supposed to obviate them from my reference system at home?

I just wish they would have made them available with a seperate integrator crossover. The way they are kind of takes the fun out of having, well, speakers.

And I haven't seen too many systems built around them. They are primarily intended to be a home theater product. Haven't seen too many home theaters with them, either. Pretty hard to get any WAF on six of those puppies all round the room, eh? They don't exactly blend in.

Sorry to say, also- sales are the only reason manufacturers make product. Without a market, there is no reason to design product. Self powered speakers do not sell. Not in the high end. Meridian lost out big with high end powered speakers, and so has everyone else who's tried it. And, once again, the whole reason designers like Richard and myself build things is so people will BUY them. :) Selfish? Maybe. But no one wants to design the next Edsel. :hot:
 
Hi Richard,

A bass cabinet, even a very heavy one, will transfer vibrations to a horn or tweeter that creates measurable and audible distortion. Most of the full range horns I've seen have a separate stand that isolates them from the bass cabinet.

The reduced Xmax of a bass horn would generate less vibration, and this is probably why so many of the classic designs worked together so well.
 
If you look carefully at the rendering, Richard has included isolation for the midrange horn. The horn and sub enclosure for the driver are decoupled from the cabinet. If properly implemented, the isolation would be very good. In loudspeakers, decoupling is highly overrated, anyway. Better to pay attention to the vibrational signature of the overall system.
 
I have been working closely with richard over the last few months as we are both on the same degree course, and the horn assembly is intended to be mounted on thick compliant pads, so will not be directly resting on the bass enclosure.
However, the 15" bass cones rich has been testing really dont move much to produce a lot of sound due to the big diameter, so i doubt the vibrations caused will be that severe.
 
Hi everyone,

finally got a moulding off, took a while fitting it around other work but I'm ahead currently with this project.

Heres a picture, nothing has been done to the moulding after getting it off the mould. Unfortunately the mould had to be destroyed to get the grp off, so now I'll make a new grp mould off the moulding I have. This'll be better because of the inherent 'give' of grp over plaster, release shouldn't be such an issue.

If anyones interested after I've finished uni (july) I might be able to do some mouldings for a modest fee.

I'm quite pleased with initial impressions - highs seem extended, no "mass rolloff" that some people have had problems with. The sound is clean and goes to about 200Hz which is what i expected (204Hz) and then rolls off quickly. Theres currently no back chamber and the unit is running full range. What are the biggest changes when adding a back chamber? I'm thinking about putting a simple high pass filter in place to reduce dopler distortion and increase headroom.

Richard.
 

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Hi,

The horn is a 150Hz Tractrix - mouth about 72cm diameter and a depth of 40cm.

The fostex I've now had a little over a year and have been using in the 206e backhorn until now. The mods I did to this driver started with 1 coat of dammer varnish to the whizzer as well as shorting the basket. I then ordered some planet10 phase plugs, made them shiny black and installed them (incase anyone is wondering, its easy, although the paper is thicker than you expect). All the normal damping on basket + felt etc.

Richard.
 

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What was the sound difference after you added the varnish to the wizzer?

In short.... not alot. I only did 1 coat, and I was careful not to put a thick coat on. I was scared to loose the top end. I'm also now glad I didnt do any more because giving the driver a flatter responce would make it less suitable for front horns.

The small change it did make was just to take the edge off the driver.... its less 'spitty' and slightly smoother (which is all I wanted). The mod that really improved the sound was the phase plug - big big improvements and I think its an easier to perform than dammer and more reversable in that you can swap out phase plugs if you really hate them.
 

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Hi everyone,

for the second part of this project we are required to refine our initial designs to make them more suitable for prototyping in the coming few months.

I have therefore redesigned the bass cabinet a little at the top. Here's a link to a large (4000x3000) rendering of the design I'm now going to prototype, hope you like it - link

Richard.
 
Just to keep everyone up-to-date,

I took a moulding off the 1st moulding (to make a new GRP mould) and have subsequently taken 2 mouldings off that which will be the final horns I use. I've made the mounting rings from 18mm birch ply and used P38 (car body filler) to securely and perminently attach these to the horns. I only have one drive unit at university with me at the moment so can only get an idea from listening to poor mp3's from my laptop through a clapped-out 20year old marantz transister on one channel! However the sound produced appears to be of rather high resolution, even compared to my previous backhorns so I am pleased. Will be able to listen in stereo at easter :) For now heres some pictures of where I am at now:

1 2 3 4 5 6

Cheers, Richard.
 
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