Dipole tweeter options

[sfdoddsy]

Whilst pondering ways to shrink my dipoles, it struck me that since I have to change the baffle anyway, maybe this would be a good time to investigate a true dipole tweeter.

So then the question is what is available that I can (ideally) use at around the same crossover point as my current Seas Millenium.

The immediate ones that come to mind are the ESS Great Heils, but I'm open to all suggestions.

[krips]

Neo3

[Saurav]

RAAL: https://www.madisound.com/store/prod...oducts_id=9035

Beyma: http://www.usspeaker.com/beyma%20tpl150-1.htm

There's a thread on DIY audio where I think the person modified this tweeter to make it dipole.

Both are $$$

[sfdoddsy]

yes, the RAAL is a bit pricey and doesn't seem to go low enough.

[CraigJ]

Hi Steve,

Since Thomas has the "Great Heils", he would be an excellent source of info for this driver. Have you considered using something like the SS10F/4424G and BG Neo3 PDR (dipole) instead of your Millennium tweeter?

Cj
edit: Sorry Deward, my suggestion was to replace the current tweeter with both the Neo3 dipole and SS10F, similar to the NaO Note. 8O Yes, this system will become a 4 1/2 way.

[Deward Hastings]

The Neo3, while nice, doesn't go nearly low enough. It can be made part of a "two way tweeter" with any of a number of 2", 3" or 4" drivers, but the penalty in that format is vertical lobing that doesn't match at all well with the (vertical) dipole pattern of the midrange, and the issues of the additional crossover. Their pattern to the rear is typically less than ideal as well. It's not an implementation that one commonly sees in foreward-firing boxes, and the reasons for that probably apply to dipoles as well.

There is also the same problem with ribbons long enough to go as low as Millennium, and with the Heil . . . they can look nicely "dipole" on the horizontal axis, but beam and lobe seriously on the vertical, so there will be a substantial change in "first reflection" from the ceiling as you pass through crossover, and above, and in overall power response (if flat on axis). I've seen a number of reported attempts, but far fewer reported successes, of matching such tweeters to cone midranges in dipole loudspeakers. We'd probably all rather have no ceiling reflection at all, but the "second choice" would probably have to be for uniformity, not a reflected response that varies erratically with frequency.

We're left with a number of less-than-ideal compromises, any of which can be made to *look* best in one particular or another, but with no agreement whatever on what actually *sounds* best in real-world implementations. I'd love to hear what the Heils sound like in direct comparison with back-to-back Millennium . . . but doubt that I'll ever get the chance. The Millennium sound good enough (to my ears) to make it not worth the money or effort to try the Heils myself . . .

[Bear]

A Neo3 plus a Neo10 puts you in the same ballpark, price-wise, as a Millenium with greater reach into the mid-range. A Neo3 plus a Neo8 gets you similar to a Millenium for half the cost of one Millenium.

[Paul Spencer]

One word to say on this one ... OUTCH! (spoken on behalf of your hip pocket)

Another option not often considered would be a pair of compression drivers, back to back with a small waveguide for each. That gives you a lot of flexibility with crossover point, since you can cross much lower if needed.

If you wanted to get tricky, you could even time align the rear tweeter so that the acoustic centre is aligned so that the treble originals from one point in space. You delay everything else. Another reason to get the MiniDSP and have an extra channel.

[Jim85IROC]

What about a 2nd rear-facing dome? This is the approach that John K took on his NaO speakers that I have had the pleasure of hearing. I don't know what effect the horizontal offset between the two tweeters acoustic centers could have, but I suppose that you could always implement some sort of delay circuit to compensate.

I recall that when John switched his rear firing tweeter in and out of the circuit, the audible effect was minimal. I was quite surprised at how little effect that rear firing tweeter had.

[Deward Hastings]

I was quite surprised at how little effect that rear firing tweeter had.

It very much depends on the room, and the implementation. With a "dead" front wall, or even a few dB of attenuation, the rear tweeter does not have much obvious effect. Interestingly, from a "historical" perspective, one of the more common criticisms of the "original" ORION was its *lack* of a rear tweeter. Now that ORION+ (and later versions) have a rear tweeter, and John K's new "Note" has a non-switchable rear pattern as well, we see new "alternate" designs with only a forward firing waveguide.

Go figure . . .

[twest820]

The Neo3, while nice, doesn't go nearly low enough.

1.6kHz isn't low enough?

[Deward Hastings]

1.6kHz isn't low enough?

Not at the maximum SPL the Neo3 can produce that low.