Good efficient midrange driver?

sydsfloyd67

Contributor
I am considering a pair of the large diameter magnet ADS soft dome midranges (rather than the L-series) for a project.

Anyone have a favorite design in a warm and loud (efficient) midrange driver? I see that Infinity used a "Polydome" midrange in addition to more tradtional closed can designs. What other designs are notable then?

This must fit in a standard ~ 4" acoustic suspension cabinet opening.

Thanks,

-sf
 
Vifa M10MD39. Think Madisound still has 'em. Though, it's a little smaller than a standard 4" hole.

Great sounding mid... very fast, reasonably efficient. They call it 89 dB or some such, but I've had NO problem mating it with drivers of up to 93 dB sensitivity...

Another, if you can FIND one, is the Audax/Polydax 12P25. Awesome mid. Fastest gun in the west. Out of production for more than a decade, tho...

Regards,
Gordon.
 
GordonW said:
Vifa M10MD39. Think Madisound still has 'em. Though, it's a little smaller than a standard 4" hole. Great sounding mid... very fast, reasonably efficient. They call it 89 dB or some such, but I've had NO problem mating it with drivers of up to 93 dB sensitivity...Another, if you can FIND one, is the Audax/Polydax 12P25. Awesome mid. Fastest gun in the west. Out of production for more than a decade, tho...Regards,Gordon.

Gordon,

Outstanding, I hoped you'd have some ideas for me. :) I do see the M10MD39 available. On closer measurment this evening, I seem to have up to 5" available, with a cabinet hole diameter of about 4 7/8".

How do you feel in genral about the soft dome approach compared to the cone? Is there any general characteristic associated with either the dome or the cone mid?

Overall, I am trying to keep up with a 10" woofer in a closed cabinet that is crossed over up at 600 Hz. The woofer is tending to dominate the 5" polyproylene cone mid driver I'd say, so I thought I should go with a very bright and loud (efficient) replacement for comparison.

I noticed the current Infinity 4.5" mid replacment, a little black can, claims a 94 db effciency. I'm not sure what the one coming out of the Rsb is (except it has a giant magnet almost four inches across and 1" thick, and looks to be very good build quality).

-sf
 
My take, is that the cone mid will almost undoubtedly be more "lively" in the mids than a dome. Dome mids tend to be very damped, which can limit their "presence".

Dunno about the Infinity RS dome, though... but, knowing Infinity, and their penchant for having their midranges at a LOWER level than their woofers and tweeters sometimes, I'd be trepidacious about it keeping up with a "gung-ho" 10" woofer as you describe. OTOH, I'd be surprised if the M10MD39 couldn't keep up...

Regards,
Gordon.
 
I've been playing around with the midrange speaker dilemma myself lately, and it seems that using BOTH a cone and a dome makes the most sense, if it doesn't totally mess up your plans, lol. Most music is in the mid range, and that covers a lot of territory. I use that same a/d/s 2" dome, for the higher mids/lower highs, and a smaller 5 or 6" woofer, crossed to be a lower mid. That's in addition to the woofer, of course, and a super tweeter. :)
 
The 2" aluminum dome midrange (crossed over at 550Hz & 2kHz) has plenty of presence in my Energy Veritas 2.4i speakers.
 
Rsb approaching very good now......

GordonW said:
Vifa M10MD39. Think Madisound still has 'em. Though, it's a little smaller than a standard 4" hole. Regards, Gordon.
Gordon,

Does Vifa do anything similar in a 5" midrange driver?

I think if I pursue this experiment, after discovering and correcting that the previous owner had the crossover incorrectly connected (phase of woofer and asymetric on the tweeters), it would be to try to get more of the low midrange. The upper mids on the Rsb are now nicely present, EMITs are bright, the 10" suspension cone vibrates the floor. I notice the 5" mid driver, which has a great flat wide magnet, doesn't move much at all- rather acting almost as a low tweeter. Compared to what one finds in an 8" two-way as far as imaging and realism, the Rsb could STILL maybe use some help there (and this is getting quite interesting)?

(Alternately, Suppose this could be aging crossover caps? Should that 5" mid be moving more? It is clear polyproylene with a black rubber surround and in great condition.)

Thanks much,
-sf
 
Last edited:
midranges

meniscus audio has some 4 inch lpg mids for 12 bucks.
zalytron has some focal and seas mids on sale.
 
sydsfloyd67 said:
Gordon,
... after discovering and correcting that the previous owner had the crossover incorrectly connected (phase of woofer and asymetric on the tweeters), it would be to try to get more of the low midrange... I notice the 5" mid driver, which has a great flat wide magnet, doesn't move much at all- rather acting almost as a low tweeter.(Alternately, Suppose this could be aging crossover caps? Should that 5" mid be moving more? It is clear polyproylene with a black rubber surround and in great condition.)

Thanks much,
-sf
Are you sure the woofer really was connected incorrectly? A lot of systems are meant to have one or more drivers wired out of phase. If you've reversed what was the correct connection it would cause a big suck-out around the crossover frequency and that may be what you're hearing as a lack of low-mids. At 600Hz and up your not going to see much movement out of the midrange driver. Aging caps in the high pass for the mid could possibly move the cut off frequency up leaving less overlap between woofer and mid, also older caps tend to get more resistive which could be reducing output of the mid driver. Caps are cheap (if you don't go for anything exotic) why not replace them and see?
 
ByrdWyngs said:
Are you sure the woofer really was connected incorrectly? A lot of systems are meant to have one or more drivers wired out of phase. If you've reversed what was the correct connection it would cause a big suck-out around the crossover frequency and that may be what you're hearing as a lack of low-mids. At 600Hz and up your not going to see much movement out of the midrange driver. Aging caps in the high pass for the mid could possibly move the cut off frequency up leaving less overlap between woofer and mid, also older caps tend to get more resistive which could be reducing output of the mid driver. Caps are cheap (if you don't go for anything exotic) why not replace them and see?
B.W., Oustanding informative repsonse. In terms of the polarity, I used a schematic of the crossover, which showed the + speaker terminals eventually going to what was designated (-) on the drivers. This correction added a whole lot of brightness, as one of the tweeters (left) was also reversed. Now I'm going to have to go back in there and make shure all three were intended to be this way, but they are sounding MUCH better.

As far as caps, I had come to the same thought about trying it this weekend. If I measure the resistance on these, and they are reading infiinte, is there still a likely benefit from new replacments?

-sf
 
Last edited:
A plain DC resistance measurement won't tell you much at all (unless the cap is shorted in which case it's really bad), you'd need to measure impedance to an AC signal and also measure the capacitance to tell if they've drifted much from original spec.
 
ByrdWyngs said:
A plain DC resistance measurement won't tell you much at all (unless the cap is shorted in which case it's really bad), you'd need to measure impedance to an AC signal and also measure the capacitance to tell if they've drifted much from original spec.

Easier to replace then. :) This is what I have in mind, let me know if it sounds correct to use non polarized foil film caps rated at 1-200V. I also saw the suggestion of jumping each with a 0.01-0.02 uF polyproylene caps as well.

If I can't find these locally as foil-film type, is mylar a good idea or not?

-sf
 
Last edited:
No......I have the schematic for the Rsb, and indeed, the tweeter is to be connected with the same +/- phase as the speaker itself, with the woofer and midrange drivers in reverse phase. Seems I've not heard these speakers yet despite having them playing for more than a month. Thanks for the important tip B.W. Four new metalized polypropylene caps per side are next.

-sf
 
Last edited:
Back
Top Bottom