How do you select a dipole Mid (800-3000Hz) – eg does QTS matter?

[charliemouse]

How should I select a dipole mid driver?

Typically VAS/QMS differentiates woofer vs mid in speaker of same size(e.g. M15CH002 vs W15LY001 )

I know QTS is instead the important factor for dipoles as Linkwitz discusses, but at these higher frequencies… that is of less interest?

SO, aside from frequency response/sensitivity: how do I select a suitable mid for a WMTMW setup?
[Woofers will be Seas Excel as used by Paul W / Linkwitz etc (prestige if I’m feeling cheapo) , as these are available in Europe, but criteria to choose mids by eluding me] Thanks.

[el`Ol]

What about something really small for less beaming like the 44-8 from accuton?
http://www.accuton.com

[Rudolf]

TSP or xmax aren`t the determinig factors in your projected frequency range. Most mid drivers get problems with non-symmetric front/rear radiation from ~1500 Hz up. So you have to look for a very open basket and preferably neo magnet to reduce acoustic blocking/shielding in the rear.


I´m not shure if the ACCUTON C²44-8 has an open back at all.

[el`Ol]

Originally posted by Rudolf

I´m not shure if the ACCUTON C²44-8 has an open back at all.

Good question. I thought it should be so because TSPs are given. A bit off topic: Do you know whether the Davis TW 26K i open back? As probably the only high quality cone tweeter and half the price of an AMT it could be an alternative for mounting two dome tweeters back to back.
http://www.davis-acoustics.com/gb/tw26k.htm

[Rudolf]

Originally posted by el`Ol
Do you know whether the Davis TW 26K is open back?

You are lucky! I got issue 4/2002 of HobbyHifi with tests for both a C²12 and the Davis. While the Davis at least has a (removable?) plastic back cover with some inside volume, the Davis does not show any opening to the back. So it will need back-to-back mounting

[tinitus]

Interesting 3" dome from TB

http://www.tb-speaker.com/detail/1208_03/75-1558s.htm

[charliemouse]

Thanks those mentioning / discussing accuton: I'm not sure how much open back will effect these frequencies. Most of the dipole benefits are at lower frequency, and most people seem to have come up with satisfactory solutions which have a single forward facing tweeter (I know SL introduced a rear firer on one model). I'm guessing at the top end of my mid driver's response it may not matter if it only fires forwards. If I go for a construction like Paul's Mules, the driver won't have to go too low as there will be additional mids

Originally posted by tinitus
Interesting 3" dome from TB

http://www.tb-speaker.com/detail/1208_03/75-1558s.htm

Now their speakers I'm intrigued at. That one has great senstivity, with the only down side being it looks like a huge wart

I always liked the look of this speaker

Sensitivity very poor though I've heard some discussion of using them as a midrange, but I'm guessing the sensitivity of these would make possibilities of passive x-overs less likely / more work.

Originally posted by el`Ol



Good question. I thought it should be so because TSPs are given. A bit off topic: Do you know whether the Davis TW 26K i open back? As probably the only high quality cone tweeter and half the price of an AMT it could be an alternative for mounting two dome tweeters back to back.
http://www.davis-acoustics.com/gb/tw26k.htm

Wow! I've looked at BMM's site, who supply these in Europe and they have them!!! (Compared to US, We have such problems and high prices getting drivers, including European ones, in Europe)
So yes, Wow, as I was saying. I really really like the appearance of that speaker. It is stunning. I can't help but notice their frequency response includes only on-axis: but I suppose buying a cone not a dome you know what you're getting. In truth though, I'm (sorry about this) very interested in the certain aspects of the sound of many 70's speakers, which despite so many shortcomings, just offer something extra from the very small cone mids. That 'something' may well be colouration and badly designed crossovers, but I should think the fact the high mid range is produced from neither a (typically) 25mm bit of stiffened cloth nor a 160mm+ heavy cone might have something to do with it
I'm very very tempted to get a couple of those for a test panel and see what they sound like. I need to order some large woofers for a sub so I should think I'll make the most of the postage and get a couple of these wasp like creatures.
Thanks for pointing them out!!!

Davis have some stunning looking drivers (woofers etc). i just wonder what posessed them to cast the frames in shapes that are so much more work route out!

[tinitus]

Sorry to say, but that little Davis has a Fs of 1050hz ... but I dont know how that works with such a driver

How about the little Jordan, it should be very good quality

[el`Ol]

I heard the little Jordan as midranger in a japanese box at the Highend in Munich and I didn`t like it. The Accutons are an other cup of tea.