Beyond the Ariel

[Variac]

Lynn is well aware of the H A co-ax's. I suspect that they are the first thing that he will try. It's just that all published co-ax speakers have serious anomalies, so we are getting prepared for possible bad news with the HA co-ax's too. Assuming they ever arrive.

As far as a custom coax, we sure wouldn't want them to make more than maybe 2 as who knows if this polepiece idea will really work. I have respect for people who know their business, and for that reason suspect that the screwy response is probably inherent to co-ax's not because the makers are stupid. I think it is better t o just get some drivers, some instrumentation , and play around with the coax options.
If we come up with something great, then sure, have them make it...

I don't know for sure, but I don't think vented polepieces have a hole all the way through. Worst case, you have that flexy tinsel wire running from the tweeter , through the big cone, and to terminals. Probably you can scavenge some..

[Zen Mod]

Originally posted by Variac
.............

I don't know for sure, but I don't think vented polepieces have a hole all the way through. Worst case, you have that flexy tinsel wire running from the tweeter , through the big cone, and to terminals. Probably you can scavenge some..

vented polepieces usually have hole all the way through

[planet10]

Originally posted by johninCR
For drivers with a vented pole piece, does the hole typically run all the way through to the front, like with the coax's with a screw-on tweeter? ie a place to run the wires for the tweeter.

yes

dave

[planet10]

Originally posted by Variac
that flexy tinsel wire running from the tweeter , through the big cone, and to terminals. Probably you can scavenge some..

Yes... i can start being more thorough with my salvage to recover those in case (i probably have 50 drivers waiting for the scrap metal guy and more if i can't find someone i can give all the good drivers in need of resurround)

dave

[johninCR]

Originally posted by Zen Mod
vented polepieces usually have hole all the way through

That's what I figured, and brings up something that always bothered me. Doesn't it make for an awfully big leak in your cab?

[Zen Mod]

Originally posted by johninCR


That's what I figured, and brings up something that always bothered me. Doesn't it make for an awfully big leak in your cab?

nope if you have dustcap

if you (hehe-your driver,to be precise) have no dust cap........that leak is already counted in bigger picture

[planet10]

Originally posted by johninCR
That's what I figured, and brings up something that always bothered me. Doesn't it make for an awfully big leak in your cab?

The dust cap has to be air tight -- unfortunately is is rarely sound-proof so besides the usual oil can resonance of the voice coil above the pole-piece you have another one from the vent. Also tends to make them noisy in a dipole.

dave

[Lynn Olson]

Once again I shamelessly thread-jack. I've started a parallel question-and-answer over here.

The reason I jumped over there temporarily is that the question is rather narrowly focussed, and aimed at one set of drivers.

As for the discussion currently in progress here, it isn't always mentioned that very few speakers do the dustcap thing correctly. Most have what amount to a cosmetic dustcap that is considerably bigger than the VC assembly; although it looks KOOL it really screws up the sound, creating a cavity resonance between the pole-piece and the dust-cap. It also creates a standing-wave on the cone itself, since the impulse radiates out from the VC assembly and meets a reflection when it hits the fairly rigid dustcap.

The little Vifas I use in the Ariel were probably designed by old man Skaaning, since the dustcap avoids the KOOL look and instead is correctly designed: it is the same size as the VC, attaches directly to the VC former and the base of the cone, and - most important - is made of a lossy material, in this case the same soft rubber as the surround.

Another appropriate material is soft felt, which like rubber, improves the mechanical termination where the VC meets the cone. Without some damping at this absolutely critical location, the mechanical disruption caused by the turn in direction and materials with dissimilar speeds-of-sound creates a substantial reflection, which then in turn creates standing waves on the cone.

Drivers with KOOL dustcaps are designed by companies that value looks more than sound, and merit removal for that reason alone. Remember, the true acoustic function of a dustcap is to quiet the reflection at the VC/cone junction. It can't possibly do that job when it's not on the VC former!

After removing the cosmetic dustcap, the resulting unsightly gap can be healed with either a disk of soft felt or a phase-plug, your choice. They do not sound the same, so the choice is up to you.

[Pano]

Originally posted by Lynn Olson
Remember, the true acoustic function of a dustcap is to quiet the reflection at the VC/cone junction.

And all this time I thought they were to keep out dust and bugs.

And to print logos on....

[swak]

There is also Fane, another maker of Coaxial drivers that has not been mentioned. They have 4 models Co-axials

DX10 143,87
DX12 143,09
DX12HE 159,03
DX15HE 181,44

The 15 inch coaxial has had good reviews over at the AA board. The are compared very favorably against the tannoys, and have a sweet 181 EUR price (without CD). I think you can use any standard compression driver on it, for example the very well regarded small BMS Lynn mentioned.

There is also Radian, but I have read the fanes counld be better. The problem with the fanes is finding them and even finding response curves in the web. Maybe writing them directly can help. The us sellers that carry fane dont list the coaxes. the prices I quoted above are in Netherlands.