another tweeter approach
Hi,
when looking for a more conventional but high efficient tweeter, maybe you should also have a look on the VIVA ringradiator.
There is a customized version made by Gerd Lommersum / the german VIVA distributor. You find his email adress under "Kontakt" on the german VIVA page
http://www.vifa.de/
"http://www.vifa.de/"
He puts a short Horn in front of the ringradiator adding efficency and directivity.
There are measurements made from a german magazine that indicate very low distortion up to around 14 Veff even at 2 kHz.
http://www.lautsprechershop.de/pdf/vifa/bausatz/mpr2-hxt-1.pdf
"http://www.lautsprechershop.de/pdf/vifa/bausatz/mpr2-hxt-1.pdf"
http://www.lautsprechershop.de/pdf/vifa/bausatz/mpr2-hxt-2.pdf
"http://www.lautsprechershop.de/pdf/vifa/bausatz/mpr2-hxt-2.pdf"
greetings
Michael
Hi,
when looking for a more conventional but high efficient tweeter, maybe you should also have a look on the VIVA ringradiator.
There is a customized version made by Gerd Lommersum / the german VIVA distributor. You find his email adress under "Kontakt" on the german VIVA page
http://www.vifa.de/
"http://www.vifa.de/"
He puts a short Horn in front of the ringradiator adding efficency and directivity.
There are measurements made from a german magazine that indicate very low distortion up to around 14 Veff even at 2 kHz.
http://www.lautsprechershop.de/pdf/vifa/bausatz/mpr2-hxt-1.pdf
"http://www.lautsprechershop.de/pdf/vifa/bausatz/mpr2-hxt-1.pdf"
http://www.lautsprechershop.de/pdf/vifa/bausatz/mpr2-hxt-2.pdf
"http://www.lautsprechershop.de/pdf/vifa/bausatz/mpr2-hxt-2.pdf"
greetings
Michael
Nah, this is just an option. Nothing is ruled out I believe. And it would be true co-ax, just that it's assembled by us.
those Vifa tweeters modded with horns are very interesting. Here is a dome rated at 95 dB
http://www.vifa.de/produkte/DBHT260HVF.pdf
not too big in diameter...specs not so bad...Without the flange it would be 3"
The ring radiators might be better but seem to be larger diameter horn and they don't seem to be very efficient.
If making our own, I think this is a case where a neo magnet tweeter is what we want. To me the shallower the magnet structure and the smaller its diameter, the better. Then it gives us more flexibility to make the tweeter structure a better phase plug for the woofer, and increase the possibility of perfect physical time alignment.
I have a couple of extra Beta8CX's, so I'll have to try one of those tiny neo tweeters with it.
I have a couple of extra Beta8CX's, so I'll have to try one of those tiny neo tweeters with it.
Variac said:
There is a relationship between voice-coil size & how high a driver goes.
Lightbulb shaped phase plug?
Also keep in mind that with the smoothest horns the edge should terminate flat and then smoothly roll backwars. My 1st choice of a profile is probably Le-Cleach's, so i'm guessing a margin over the theoretical will be needed. As well you need to consider that the XO is not infinite so that requires a bit more room too.
dave
Absolutely!
Neo for the tweeter is probably going to be the best solution.
In fact, that's why that horn driver that Lynn likes is so small.
Lightbulb phase plug is certainly a possibility also- after all some people use that shape because they think it works best for their speaker.
Pano,
What we need I think is 12" drivers that have smooth response out to 3k and have at least a 3" voice coil, 4" preferred. Because a smaller v.c. seems to help with wider range response, the candidates are pretty rare it appears.
The TT Super Boy 15" might be a contender. It even has a nice cast frame- Not ALnico mag though... Do the Tone Tubby people publish any specs at all?
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..
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..
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.
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.
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.
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.