hello Mykey.

Hi HBL!

the mykey one is not letting me in, thats when I thought I'd been too much of a naughty boy
so I'll stick with mykey-
cheers
and sorry again

Tony.A.S.S. wrote: That's an interesting concept. No cone phase problems, and the low end that goes missing through lack of cone is probably re-gained by the size of the horn. I guess it would sound clean and transparent.
Perhaps we could try this with some PD's that have ripped themselves apart.

unreal, so natural smiley32

I'm already on this Tony, lets see how we get on
little sketch as to what 'maybe' going on

maybe this could be adapted for PA, so a bigger dust cap :ugeek: horns would end up humongous though

Tony, look at the "HALO" (lol) above my head, you can see the dust cap

Heathrow_B_Line wrote: See how grown up I am I didnt even mess with your pic

cheers, tweet is already calling me Clint Eastwood on Facebook because of that pic lol

It wouldn't be plain sailing trying to adapt a PA speaker for this purpose. Firstly it would have to be a mid speaker. Taking a cone off and putting a dust cap in it's place would not prevent it from working, but wouldn't give the optimum results, as the suspension, regarding compliance, would be set up for the weight of the cone and the surround. But that would only mean getting the right spider sorted, of which there are many to choose from.
I had originally thought of a horn in front of the Volt mid, because, unlike the ATC mid, which has curved sides, the Volt has straight 90 deg. sides which would make the coupling easier. My thoughts were to get the unit with the help of the horn gain, up to the efficiency of a PA speaker. It would need a gain of about 6db. So the horn would have to be quite large.
One last thought about this, haven't Community been doing this for years. And aren't the latest co-axil compression drivers like this. I know the B and C use a composite material for the mid section.

The mid on the BMS coaxial (obviously I've had mine apart smiley1 ) does resemble a small speaker cone. Its toroidal, so it doesn't meet at the middle but radiates a ring. It actually has a tiny little suspension giving +/- 0.8mm excursion so can move more air than most comps at the cost of having higher front chamber volume which is why it cuts off at 6K.

However, like other CDs, it drives a series of slots, with a compression ratio around 1:10 which then expand gradually into the throat.

With the dome-goes-directly-into-horn idea mentioned above, I would wonder about impedance matching. Reducing cone area drives up source impedance (BL/a)^2 considerably. If the mass and BL are low that would be OK. Also, if the horn mouth is big enough to be well damped by the air, then a mismatch at the throat wouldn't be a problem.

I have a feeling we may be looking at something that has great sound quality because of the simplicity - no cone to flap, resonate or cancel; no phase plug to maybe resonate. But LF extension and power might be limited by excursion given the low loading.

No reason not to try building one though, there may be lessons to be learned.

Regarding your comments about cone flap etc. Isn't it a strange phenomena that the very things you need to make a speaker work, sometimes are the things that make it sound bad.

I have a cheap Chinese floor monitor where the top end appears to be a standard soft dome tweeter allied to a very shallow horn
(approx 15deg) around 60mm long. Similar to what Audax did a few years ago.

I don't see how you would do it without the surround being terminated at the throat of the horn.

Tony

You would have to seal the spider and the dome in a shallow cavity behind the driver plate of the horn. With the hi fi components, this isn't an issue, because the horn can be connected straight to the plate.