Anyone know why dome midranges cost so much?

[SpacePatrolman]

That's pretty much the whole question!

Even the least expensive dome mid sold by PE costs $25 right now. :( I realize they usually use rather large magnet structures which may account for the price difference vs. cone mids. But many woofers in the 6.5" and 8" range can use the same size magnet and utilize much more material i.e. woofer cone, spider, surround, basket etc but can cost the same or less.

Bonus question : are there any technical reasons dome mids aren't used more often?

[tombond]

Re: Anyone know why dome midranges cost so much?

Without doing any research, my first guess would be a product with less demand equals fewer units sold which leads to higher unit markup to recoup investments and still make a profit. I'm sure someone else can be more succinct.

[Wolf]

Re: Anyone know why dome midranges cost so much?

That's pretty much the whole question!

Even the least expensive dome mid sold by PE costs $25 right now. :( I realize they usually use rather large magnet structures which may account for the price difference vs. cone mids. But many woofers in the 6.5" and 8" range can use the same size magnet and utilize much more material i.e. woofer cone, spider, surround, basket etc but can cost the same or less.

Bonus question : are there any technical reasons dome mids aren't used more often?

The reason they aren't used more offten is due to a slightly limited FR curve, and that you have to treat them a little differently to get good sound from them. That and of course the supply/demand curve like Tommy mentioned.

That said- I love a good dome-mid when done-right. In some driver cases, they're kinda a mid-tweeter, and can't play low enough. Then they are too large in frame-diameter to typically xover high to a miniscule tweeter. It's almost a driver destined for a 4-way with a conical lower mid, and a decent tweeter.

My 2c,
Wolf

[mzisserson]

Re: Anyone know why dome midranges cost so much?

That said- I love a good dome-mid when done-right. In some driver cases, they're kinda a mid-tweeter, and can't play low enough. Then they are too large in frame-diameter to typically xover high to a miniscule tweeter. It's almost a driver destined for a 4-way with a conical lower mid, and a decent tweeter.

My 2c,
Wolf

Reminds me of the old Infinity, circa late 90's stuff with 1 4" mid-dome. They sounded really, really nice if memory serves.

I agree, they are hard to work with an you can "go further" with a cone.

[ligs]

Re: Anyone know why dome midranges cost so much?

Usually a dome midrange does not have a spider. A spider in a cone midrange helps centering the voice coil and also prevents the rocking of voice coil during long strokes. Therefore, designing a dome midrange takes more skills.

A really good one like that of ATC costs a lot. I used Dynaudio D 54 and 52 before. They sounded smooth but did not have much inner details, however.

I have also read anecdotal evidence that during the 1970’s the top rated US speakers like Allison 1 and AR 3a (both have dome midranges) did not image well compared to British made ones like KEF and B&W which used cone midwoofers or midranges. It was suspected too wide a dispersion in the midrange contributed to the difference in imaging quality. I don’t know how true was this, however.

We do know that Bose 901’s which do not image well and they have more diffused sound than typical speakers.

[jeffc52053]

Re: Anyone know why dome midranges cost so much?

I have 2 Vifa DM75's (3" dome mid) that I used in a 3 way tower. Hi-V Ribbon did the top end and 2 Dayton 8" did the bottom. They were hard to design a crossover as they are pretty efficient (93 db). Utilmately I used 18 db @750 hz.
Once I got the crossover right, they sounded very good (imaging was great)
I no longer use these drivers as I've gone to Pioneer 6.5's and a Morel CAT 378 dome tweeter for 5.1.

[ClosetSciFiGeek]

Re: Anyone know why dome midranges cost so much?

Love the RS52's in my ZDT3.5's. I have a really wide room with lots of seating for movies and the RS52's and ND20's are REALLY good off axis, especially for dialog. They were definitely worth the money for me versus a more traditional cone midwoofer.

[SpacePatrolman]

Re: Anyone know why dome midranges cost so much?

Appreciate the info everyone!

The reason they aren't used more offten is due to a slightly limited FR curve, and that you have to treat them a little differently to get good sound from them.

Treat them differently because of the limited frequency range, or some other issue?

[MagicO309d]

Re: Anyone know why dome midranges cost so much?

Love the RS52's in my ZDT3.5's. I have a really wide room with lots of seating for movies and the RS52's and ND20's are REALLY good off axis, especially for dialog. They were definitely worth the money for me versus a more traditional cone midwoofer.

+1 on the ZDT3.5's, I'm using them for 2 channel music only and they work great in my 15 x 22' room.

I conceptualize the RS52 and ND20 together as a very cheap, $60 "magic" tweeter that plays cleanly down to under 900 Hz. In other words, a dome midrange isn't expensive because it allows the use of a cheap tweeter that together can beat the performance of the very best tweeters for pennies on the dollar!

[Wolf]

Re: Anyone know why dome midranges cost so much?

Appreciate the info everyone!

Treat them differently because of the limited frequency range, or some other issue?

The excursion can be an issue, it's off-axis response is different, breakups, etc. You have to make them comfy. I used full comp on the DMN-A in my NEHD's; zobel, LCR, etc.
Later,
Wolf

[ligs]

Re: Anyone know why dome midranges cost so much?

I will venture another point. The woofer, mid and high range need to match in coloration as well not just FR. It appears Dayton’s 2-inch aluminum dome is a very good one(to match Dayton RS 180, also made of aluminum) but I have not tried them yet.

However, Some dome midranges of the past such as Philips (AD 0210 paper), Dynaudio (D-54, D52, fabric) were just too soft. You wonder if they are capable of moving as a piston at all. We know we want a stiff woofer but the transition from the stiff woofer to the very soft dome midrange might be problematic. Transition between the midrange and tweeter seems to be less a problem however. It is interesting that the original AR 3a 1.5-inch fried-egg midrange was a stiff paper dome. It had a very sharp breakup somewhere beyond 10k and did not seem to bother anyone. Only much later AR started using soft dome tweeter (in AR 10 pi and 11)and then soft dome midrange(AR 9) as well, probably more for their increased sensitivity than absolute quality.

[Pete Schumacher]

Re: Anyone know why dome midranges cost so much?

I will venture another point. The woofer, mid and high range need to match in coloration too not just FR. It appears Dayton’s 2-inch aluminum dome is a very good one but I have not tried it yet.

However, Some dome midranges of the past such as Philips (paper), Dynaudio (fabric) were just too soft. You wonder if they are capable of moving as a piston at all. We know we want a stiff woofer but transition from the stiff woofer to the very soft dome midrange might be problematic. Transition between the midrange and tweeter seems to be less a problem however. It is interesting that the original AR 3a 1.5-inch fried-egg midrange was a stiff paper dome. It had a very sharp breakup somewhere beyond 10k and did not seem to bother anyone. Only much later AR started using soft dome tweeter (in AR 10 pi and 11)and then soft dome midrange(AR 9) as well, probably more for their increased sensitivity than absolute quality.

The Tang Band 3" dome uses fabric and I do believe that the ATC 3" dome does as well . From a purely objective standpoint, there's not likely a cleaner performing mid than the Tang Band, and I'm sure the ATC is no slacker either. The non linear distortion levels of the TB are minuscule, and I've not seen a cone driver that can match it.

The problem with the mids is that their range is limited. If you want sensitivity, you sacrifice low end. The practical limit on the TB as well as the RS52 is around 600Hz, with 4th order slopes. Anything lower and you'll run into excursion issues, especially with the RS52 due to its much smaller surface area.

They do make ideal mid drivers for three ways that will make use of a sub. There are any number of 7 to 10 inch woofers that can be run to 600-800Hz and mated to a dome mid. But asking a woofer to cover the first couple octaves, and then cleanly handle midrange duties to 800Hz is a tall order. Relieving the woofer of the low bass, excursion consuming chore, allows the woofer to play far more cleanly to the higher XO point where the dome mid works best. A very nice example of this is the Black Box project in the Showcase.

In the case of the TB mid, you get what you pay for from a performance standpiont: Extremely low distortion delivered over the 600-2500Hz range. The RS52 is good to 3500 thanks to its smaller size. And I have to agree with the earlier assessment of the ND20/RS52 combo. They make a splendid "super duty tweeter" with great off-axis performance and crystal clear dialogue. The missus reminds me all the time how much she likes what she hears from the Prisstinas.

[SpacePatrolman]

Re: Anyone know why dome midranges cost so much?

The excursion can be an issue, it's off-axis response is different, breakups, etc. You have to make them comfy. I used full comp on the DMN-A in my NEHD's; zobel, LCR, etc.
Later,
Wolf

Thx again!

Fun factoid : this is the largest dome driver I know of, though being crossed over at 90Hz(!) it must be called a dome midbass: Kappa 8.

[mgrabow]

Re: Anyone know why dome midranges cost so much?

I have used them in the past in 4 way designs and they work well in that application. However, in a 3 way speaker I have been disappointed.

[bmaupin]

Re: Anyone know why dome midranges cost so much?

This is the largest I know of

http://www.diyaudio.com/forums/planars-exotics/150426-dome-woofer.html