Cleanest 12" high efficiency mids for the money?

[audiokinesis]

Is this the Nick McKinney from Melbourne, Florida??

Yup, Nick - it's the same Duke. Technically I live in Idaho these days, but I'm still from New Orleans.

[nickmckinney]

Originally posted by LineSource


Hi Nick,

Do you plan to prototype and measure a few new "ultimate midrange" speaker designs? Putting your underhung motor on a TD10M or TD12M would be interesting data.

Very low Mms, like 30g for a 10", a flat flux underhung motor, 8mm Xmax, and ~94db/watt SPL seem necessary for an ultimate midrange. Pre-magnetized NdFeB might be managable for a couple prototypes. The tapered outer pole steel like that used by TC Sounds in their underhung motors to get linear flux over the full gap length and a solid steel center pole cylinder might be able to handle NdFeB higher flux without saturation.

I once made a TD15M with a 6mm tall voice coil originally intended for an Altec 755 inside a gap of 8mm so it can be done especially with lower power handling criteria. Actually the person that owns that driver lives close by again (it was mounted inside an antique radio)

2" diameter of Neo is not going to help us much though. I think the Alnico motors we are drawing up now would be the best route for this (especially combined with a 1/4" tall voice coil winding)

Originally posted by audiokinesis
Is this the Nick McKinney from Melbourne, Florida??

Yup, Nick - it's the same Duke. Technically I live in Idaho these days, but I'm still from New Orleans.

Glad to hear you are out and about, we need to meet up again. I would imagine the place in NO didn't fare too well........

[Rybaudio]

A while back I was in the market for a 12" midrange just like what you want. I settled on the B&C 12PE32. Put it in .35-.5 sealed and you'll have a direct radiating midrange with 102 dB sensitivity from 200-1.5k Hz, and a very clean, well-behaved response in that region. Power compression is very low (<1 dB) up to 120 dB (1m) and nonlinear distortion is neglibible way past that. Excursion wise, the unit has 5 mm each way clean and 7.5 mm each way usable.

The only comparable driver I've seen for that application is the JBL 2020H (I think that's the model... the 12" midrange), but it's much more expensive. A friend of mine runs the Delta Pro 12 from 100-1.5k and it works well, but I don't think it's in the same league as these others for midrange usage.

[Graham Maynard]

Hi BHTX,

Some test results here;-

http://www.prodance.cz/protokoly.php?AnchorID=51&Lng=CZ

Cheers ............ Graham.

[JoshK]

Did you end up deciding?

[tinitus]

Originally posted by BHTX

..Would be perfect for 1 ft^3 sealed, crossed around 150-200Hz & 1.2-1.5 KHz to a large woofer and waveguide. What do you think?

Seems much depend on the size of the waveguide
That is if a waveguide like the 18Sound 1086(?) or similar size is used an 8" mid would probably be a better choice
Fore a bigger mid you will need a bigger waveguide ... it seems

[BHTX]

Yep.. that's the problem. No one makes a big enough waveguide available off the shelf.

I've looked into those from Eighteen Sound as well.
Something like the XT1464 with a 1.4" CD and a super tweeter like the B&C DE35 might do well.

[tinitus]

I have been around a 12" mid too, but have second thoughts
To me there was a reason fore looking at a 12" mid ... I wanted to croos very low to a big sub, but now I dont see that as an option
Instead of a sub I think its much better to used a woofer with good Xmax and then use a little EQ ... no need to be straight to 20hz either
I can see why pros use 12-15" mids, but fore home use I see no reason
Sure, some have shown a 15" to work up to 1khz in a 2way, and fore this there is a reason fore a big driver doing bass duties as well
But doing a 3way a smaller mid seem to make more sense
True, there may not be many smaller pro mids to choose from, but there are some
Further, cross a bit higher and a 1" CD in a smaller waveguide ought to work fine

Though, Beyma makes an interesting 100db AMT ribbon

But actually I find this high power thing a bit confusing, so I have decided to take a step down and do 93-95db speaker and get better FR exstension instead ... until I change my mind again and again

[BHTX]

If there were larger waveguides out there, a 12" mid would be a good compromise between low and high frequency extension, with the goal of obtaining good directivity as low as possible. Mainly, the smoothest of the high output 10" mids just don't go low enough for me in small sealed chambers. Ideally, I'd like to cross to the 15" woofer no higher than about 200 Hz LR4 while obtaining 4th order rolloff nearly an octave down. If you use a 10 with this ability, not only is it going to be less efficient, but higher freq reproduction will usually suffer a bit. A fairly low cone mass for a given Sd is usually good in this case, and a 12" mid can have those characteristics while still playing low enough to get down to 150-250 Hz with a 4th order slope.

As for that Beyma AMT, my most recent project dealt with a pair of Heil AMT-1's, so I'm not really interested. Mainly, I recently saw some 3nd party measurements of that Beyma and wasn't too impressed, to say the least. I had expected better performance from that driver, perhaps more along the lines of the Heil's, but it didn't quite appear to be that way.

[tinitus]

There is one pro 12" mid that I would like to give a try, but I dont know if you can buy it outside EU

http://www.precisiondevices.co.uk/showdetails.asp?id=70

btw, how about a driver from GreatPlainsAudio ... theres a 12", not very high SPL, but looks very nice