- Aluminium conducts heat in a much better way than steel.
- Ferrite magnets can take higher temperatures than neodymium ones can.
- Occasional power peaks are usually incapable of causing power compression but larger VCs (>3") are better than smaller ones (home or PA).
- Higher linearity maybe obtained from the reduced excursion of larger drivers.
People focus on heavy boxes, but it's the magnet at the "coal face" providing the main block of inertia before the vibrations even reach the box via the basket spokes.
Intuitively, a 2kg magnet pushing against a 50g voice coil and cone will be 6dB quieter than a 1kg magnet of equal strength pushing against the same 50g. On the other hand, there could be some design differences unrelated to just swapping in a thinner ring.
The basket rigidity is critical to a drivers overall performance. Thats also why supporting the magnet structure helps transfer more force to the cone than just a heavy, stiff high mass enclosure. Some of the older Kef speakers used magnet support dowels and had a cleaner lower midrange sound IMO. You could have a stamped frame basket perform as good as or even better than a cast basket by itself without a motor suport or bracing.
The Dayton PA310 is my favorite 12" stamped basket driver. It has alot of features that higher end drivers have, but a very rigid basket design with very good support and a well designed motor. This driver outdoes some $300 drivers in several areas. Its a beast in folded horns, which is quite an achievement for a $100 driver.
The Eminence Beta8A is one of rhe best 8" midranges I've ever heard. It does this without flux demodulation and a cast basket. Not a pretty driver, but one of the best pro mids at any cost. They were either very smart or just plain lucky designing this driver.
The Eminence Beta8A is one of rhe best 8" midranges I've ever heard. It does this without flux demodulation and a cast basket. Not a pretty driver, but one of the best pro mids at any cost. They were either very smart or just plain lucky designing this driver.
I think that's one of the reasons I have started to prefer drivers with very low moving mass. It also creates a lot less force that's trying to move the enclosure in the opposite direction. Newton's 3rd law and all that jazz.
I made myself a list of good quality pro drivers with very low Mms to Sd ratio. Esoteric and expensive stuff has not even been considered. The same goes for typical guitar- or fullrange drivers.
| Manufacturer | Model | Diameter | Sd cm2 | Mms grams | Mms/Sd ratio |
| Eminence | Delta 12B | 12" | 519,5 | 32 | 0,0616 |
| 18Sound | 12NMB420 | 12" | 531 | 33,5 | 0,0631 |
| Eminence | Alpha 12A | 12" | 519,5 | 33 | 0,0635 |
| Beyma | 12GA50 | 12" | 530 | 34 | 0,0642 |
| 18Sound | 15W500 | 15" | 850 | 55 | 0,0647 |
| Fane | 15-300TC | 15" | 855 | 56 | 0,0655 |
| 18Sound | 12NDA520 | 12" | 531 | 36 | 0,0678 |
| Volt | RV3153 | 12" | 479 | 33 | 0,0689 |
| Eminence | Alpha 15 | 15" | 856,3 | 59 | 0,0689 |
| B&C | 12PE32 | 12" | 522 | 37 | 0,0709 |
| Eminence | Deltalite II 2512 | 12" | 519,5 | 37 | 0,0712 |
| Eminence | Delta Pro 15 | 15" | 856,3 | 61 | 0,0712 |
| Eminence | Delta 15 | 15" | 864,6 | 62 | 0,0717 |
| Lavoce | WSN122.50 | 12" | 530,9 | 38,5 | 0,0725 |
| Eminence | Beta 15 | 15" | 823,7 | 60 | 0,0728 |
| Eminence | Beta 12A | 12" | 538,9 | 40 | 0,0742 |
| Eminence | Delta 15LF | 15" | 856,3 | 64 | 0,0747 |
| Eminence | Delta 12A | 12" | 519,5 | 39 | 0,0751 |
| Oberton | 12L300 | 12" | 514,7 | 40,65 | 0,0790 |
I like Eminence 12A.
I've made a few pairs of mid bass horns for folk over the years.
They usually come with ideas that an expensive driver, huge magnet, fancy basket etc etc, (admittedly usually a sub woofer type), will be best.
I model their driver - it's terrible.
I model the 12A - it's great.
I convince them..
I build the horns, measure them, and the measured frequency response is pretty much as modelled.
They sound good too!
I've been using Eminence Kappa Pro 15" LFIIs in my tapped horns for over 10 years now!
I guess they are a bit fancier then real cheapies.
I was using Eminence 15As in my mid bass horns, but a few years ago switched to the 12A myself.
It's my mid bass horn 'goto' driver 🙂
I've made a few pairs of mid bass horns for folk over the years.
They usually come with ideas that an expensive driver, huge magnet, fancy basket etc etc, (admittedly usually a sub woofer type), will be best.
I model their driver - it's terrible.
I model the 12A - it's great.
I convince them..
I build the horns, measure them, and the measured frequency response is pretty much as modelled.
They sound good too!
I've been using Eminence Kappa Pro 15" LFIIs in my tapped horns for over 10 years now!
I guess they are a bit fancier then real cheapies.
I was using Eminence 15As in my mid bass horns, but a few years ago switched to the 12A myself.
It's my mid bass horn 'goto' driver 🙂
I've used four Eminence Delta 12B 16 ohm (the one at the top of my list above) in my dipole mid-bass system. It's simply great. High efficiency, extremely low distortion and no sign of resonances in the 100 - 450 Hz range where I use them.
Sorry, we did not take many photos. They were all closed boxes and had 24LR LP at 500Hz and ran with no HP during testing, simply to see how low they would go.
Point is, there wasn't much to say about" detail or "speed" or any other attribute you might put on any given driver. Mostly it was a matter of sensitivity, max SPL and linearity. What I mean about amplitude variance is, that the SB23NRX start to break up at around 700Hz, which makes them a little less "clean" to cross. When I play with the Purifi at home, they seem easier to cross to my midrange than the SB23NRX.
When you accounted for the room, the setup, the other drivers. Using them active - as we always do - "simply" require you to EQ them straight - within reason. Doing so with the Purifi, made us lose around 10-15 SPL - if you want them to play low without a passive driver or port.
So the amplitude variance, I refer to, is simply how deep they play. All drivers were in pairs and played in around 60 liters closed. Between 90-500Hz - the room and placement of the speaker, really dominates a lot. So most drivers seem to perform very equally in this frequency area.
Unfortunately, it is more expensive than BC 12PE32, which is also perfect for midbass horns.
I would just go with what you need. If you don't need the power handling or the added efficiency just stick with what works. That's assuming the lower cost driver performs as well as the expensive one over the SPL range you will be using it over and the linearity is similar.
Rob 🙂
Rob 🙂
Yeah,
The Kappa is not a super cheapie, bit it's not super expensive either.
For me it's a bit of stick with what you know works.
I'm building a 1.74m long (horn path) exponential mid bass pair at the moment.
Modelled this
Measured this early part finished (more layers to go) horn in workshop, so not ideal. At reasonably loud volume.
Freq sweeps aways sound so loud!
+/- 5dB is a good guide when measuring, I've found.
The Kappa is not a super cheapie, bit it's not super expensive either.
For me it's a bit of stick with what you know works.
I'm building a 1.74m long (horn path) exponential mid bass pair at the moment.
Modelled this
Measured this early part finished (more layers to go) horn in workshop, so not ideal. At reasonably loud volume.
Freq sweeps aways sound so loud!
+/- 5dB is a good guide when measuring, I've found.
Nice!
Shipping seemed a lot more affordable on the Italian brands here in Poland. The Lavoce WSF122.02 was about half the price of a Deltalite II, and 1.5x cheaper than the Beta 12A. A few grams difference and I could buy a pair of Alpairs with the 100EUR saved. I also looked at VAS, with a preference for higher values, in case the mechanical spring is another source of non-linearity.
I actually bought my Eminence drivers from Blue Aran in the UK, where they are much cheaper than in my own country. Shipping was quite expensive though.
I really like the B&C 12MH32 alot. Its a very good horn driver and sounds a little more extended up top than the 12PE32.
The split winding VC is a very cool feature not commonly found on a cheaper driver. The cone is a little heavier than the 12PE32, but its also stiffer and won't break up as bad if pushed harder in a smaller chambered FLH. The cone has to deal with alot of stress on a driver in a very small sealed chamber when its run harder.
The split winding VC is a very cool feature not commonly found on a cheaper driver. The cone is a little heavier than the 12PE32, but its also stiffer and won't break up as bad if pushed harder in a smaller chambered FLH. The cone has to deal with alot of stress on a driver in a very small sealed chamber when its run harder.
Splitting the difference, I'm a really big fan of the Delta Pro 12A. I was torn between that model and the Kappalite 3012LF- the latter was quite lighter and had slightly more low end, but ultimately, I decided in the Delta Pro, largely on price. It performs remarkably well, as excellent midrange and extends far higher than I can use- in my current 4.5 cf cabinet, it will go from 38Hz to 3k at not less than -5dB; my low pass is 600Hz and with a DSP parametric eq and a 3db boost at 30-34hz, it will extend to 28Hz -3db, with room gain and a 15" passive radiator.
Try reship. If its the actual shipping that cost.
Usually its the toll fee, and the 25% tax thats the killer here.
Still a lot cheaper idd, blue aran, and lean business uk has great prices 🙂