Dipoles - mid/tweeter panel

[EspenE]

My current speaker system consists of Peerless XLS 12” subwoofers in IB boxes, with Seas metal midrange (L17RNX/P) and Seas metal tweeter (27TBFCG) in small closed “satellites”. Electronic crossover at 100 Hz and 2 kHz, power amplifiers are Elliott P101 and two old NAD 214 units.

My next loudspeaker project will be dipoles – separate subwoofers, mid/tweeter “panels”, electronic crossovers and Elliott P101 amplifiers.

Woofers will probably be ripoles with dual 12” Peerless SLS units in each. EQ-ing and filtering as required.

I am unsure about mid/tweeter panels, though, and consider two alternatives:

• “Phoenix-style” MTM dual 8” midrange (Seas metal) plus tweeter (27TBFCG, probably with a waveguide) , crossover between 1200-1400 Hz
• or a “WMT”-configuration with a 10-inch Seas metal L26 unit handling 100-300 Hz, a 6 inch L15 unit 300-2000 Hz - plus tweeter.

The former alternative is perhaps the least complicated – but I am concerned about the compromise between (on one side) the power handling of the tweeter and (on the other side) the cone breakup/distortion and the increasing directivity of the metal-cone midrange units.

The latter alternative offers the possibility of a higher tweeter crossover frequency which obliterates most of the mentioned problems - but with the added complexity of extra crossovers and units, less symmetrical vertical-plane dispersion and the need for somewhat higher cone excursion in the 100 Hz-area.

(Even though it is desirable, I have not room for bigger mid/tweeter panels with more units. I also think that MTM mid/tweeter panels with 6 ½” units (in place of the 8” units) will suffer too much in power handling and is no desirable alternative).

Any thoughts/advise on those alternatives?

Regards,
EspenE

[Rudolf]

Originally posted by EspenE
I am unsure about mid/tweeter panels, though, and consider two alternatives ...

I can´t contribute with the drivers, but regarding the increasing directivity of the metal-cone midrange units:

Crossing at 1200-1400 Hz as suggested, there is almost no increased directivity of the midrange unit itself (looking at the SEAS SPL graph). You certainly should be more concerned about the figure 8 dispersion of the dipole, which gives another kind of directivity and might be in conflict with the tweeter dispersion. But Linkwitz et al haven´t found an issue there - so why should you care.

[icebear]

Hi Espen

I'm using dual Peerlees 12" ripoles and bastanis Prometheus (www.bastanis.de) and must say it's one of the best speaker I'v ever heard. It's very sensitive (100dB/W) and can take a lot of power. I'm happy with 2watt's but it can take 200...
I used Quad ESL 63 before, and I was happy with them. But I do not miss them after the these broke in.

Here is a pic of it: http://home.no/tricoloreis/diff5.jpg

Best regards
bjørn

[icebear]

Your mailadress does not work. Send me a new address and I'll respond :-)

bjørn

[el`Ol]

Bastanis use modified Eminence widerangers. Ciare have a nice 100dB wideranger that doesn`t have that nasty peak as the unmodified Eminences before they say goodbye. I don`t know whether they reach the quality of the (much more expensive) Bastanis, but I read in a German forum that people are very pleased with it.



http://www.ciare.com/pdf/catalogo/PM250.pdf