18Sound midbass/midranges, opinions?

[thadman]

I've been browsing the web on different high-quality prosound drivers, and found these midranges produced by 18sound. I've done searches on all the major audio forums I'm familiar with and have sorted through pages of google...with no success. They look excellent, but there is absolutely no objective information (3rd party analysis) or subjective impressions (personal experience) regarding these particular midranges. 18sound's page suggests that these drivers are used in monitoring applications, so their sound quality should be excellent.

Here are the specs that I found interesting

6Nd410
180W power handling
-2/3dB at 45* at 2khz
.67mH inductance
102dB sensitivity (8ohm)
97.9dB efficiency
2mm xmax
~.7dB power compression at 113dB (12W)

http://www.eighteensound.com/index.a...roduct&pid=244

Should be excellent from 500-2khz

12NdA520
300W power handling
-2/3dB at 45* at 1khz
.03mH (yes, POINT zero three) inductance (as a result of the Active Impedance Control)
100.5dB sensitivity (8ohm)
98.9dB efficiency
4mm xmax
~.7dB power compression at 114dB (22W)

http://www.eighteensound.com/index.a...roduct&pid=240

Should be excellent from 100-1khz

Anybody willing to try these babies out?

[Hdale85]

Those links aren't working for me....

[thadman]

6Nd410

http://www.eighteensound.com/index.aspx?mainMenu=view_product&pid=244

12NdA520

http://www.eighteensound.com/index.aspx?mainMenu=view_product&pid=240

[Hdale85]

Those work! Are these rather expensive?

[thadman]

6Nd410 is $120 and the 12NdA520 should be between $200-300

[Hdale85]

Pretty pricey. They aren't metal cone either which is whats popular around here .

[augerpro]

I'd be more inclined to use the 6NMB420 for the lower Fs, longer excursion, and shorting ring. Should make it more flexible in crossing to a woofer. There are other nice 6" out there but not with 100+dB sensitivity if that is important to you.

The 12NDA520 is cool. Should be low distortion. OTOH the xmax is really too small in in my opinion.

[thadman]

I'd be more inclined to use the 6NMB420 for the lower Fs, longer excursion, and shorting ring. Should make it more flexible in crossing to a woofer. There are other nice 6" out there but not with 100+dB sensitivity if that is important to you.

This driver doesn't seem too far off from the PHL 1120 or Audax PR17. Just from looking at the specs, it doesn't seem like using it below 500hz would be a very good idea. 150cm^2 + .5mm 1-way will be displacement limited to 108dB + 6dB (if half space) + 6dB (if using L/R hp) at 500hz while using up only 1/4th of its xmax. 120dB :E The driver has 2mm of xmax, so it should be well within its linear range as a pure midrange above 500hz, even at absurdly high SPL levels.

The 6NMB420 seems like a driver more suited towards a much larger bandwidth, less specialized with reference to the 6Nd410 which of course would entail more compromises. It also appears to have very poor off-axis response.

The 12NDA520 is cool. Should be low distortion. OTOH the xmax is really too small in in my opinion.

At 100hz, you're displacement limited to 103dB + 6dB (if you've got a mono pair) + 6dB (if half space, which is likely) + 6dB (if using L/R hp) while using up only half of its xmax (2mm vs 4mm). 121dB :E

They have low xmax, but that is more than compensated for in their high sensitivity. They seem to be highly specialized for a specific bandwidth, so if special regards are paid to operating them within their optimal bandwidths, you should have excellent performance...which of course intrigued me about these drivers.

[augerpro]

I was looking at the 6NMB420 as the more flexible of the two. If the 6ND410 fits your specific design as good or better then go for it. OTOH the 8NMB420 I have didn't knock my socks off distortion wise. Respectable but not great, and a high third harmonic that will probably impact the sound. And that had a shorting ring. Without having tested the 6ND410 I'd guess that the distortion is probably worse than the 6NMB420. Of course the response of the 6ND410 is smoother, so pick your poison. I must say though that both of these cones must be very light, and it's behavior at high SPL would concern me I think. You don't get that high sensitivity for free. I tested a high sensitivity driver from Beyma that would compete with these-impedance looked pretty rough. Theoretical max SPL doesn't mean much when a light cone goes into audible breakup. I don't know that the off axis response will be all that different, the graphs don't even display the same. They are both 6" with similar cones after all. Without knowing what your specific design calls for or what you as a designer considers important I can't really say which is better.

I think your max SPL calculations are VERY optimistic of the 12NDA520. It's just outside the realm of believability at 100Hz, at 60 Hz there is no way. If subs with 30mm of excursion have a hard time hitting those numbers what makes you think this thing with 2mm of throw is going to do it? At low frequencies drivers are nothing but air pumps. Volume of air moved is what matters, not sensitivity or anything else. So matching these to a 102dB/watt mid is going to be more involved than you think. Are you using active or passive crossovers? With passive you're looking at more than one or two of these to match the 6ND410, at least if you are looking for a decent bass response out of them. Personally I'd go with a mid with a stiffer cone like the B&C 6NDL38. It would be better behaved, would cross easier to most PA woofers, and the sensitivity hit would be acceptable.

Just my .02

[augerpro]

BTW if you have your heart set on these drivers (they are nice) I'd happily measure them for you. My philosophy may not be the same as others regarding using these particular drivers, but I'm curious just the same. And I know a lot of other people would be interested in the results.

[Nemophyle]

IMO the 12" is not a sub (doesn't go as low) so it isn't needed to have the same kind of excursion.

Actually if you model it in a BR it doesn't really go lower than 60hz. Also brandon it haves AIC technology wich is known to be one of the best distortion reduction means, so it should be way better than their shorting rings drivers (the 6NMB420 has only one alu ring, wich is little in the pro audio world, since most b&c drivers have 3)

IMO also the 6" 18sounds drivers are too compromised + i don't see the use of a 6" with rather high sensivity and low excursion / extension in the bass.

I'd rather go with their 10" AIC driver , cross it over at 900hz over a waveguided compression driver like the BMS/DDS combo popular over here, and use an active powered sub for the low end. You can use the 10NDA520 also wich is the same but a tad lower sensivity and extend a little bit more in the basses

btw PaulW is known to have some experience with theses drivers, and he hangs around theses forums from times to times.

[thadman]

I was looking at the 6NMB420 as the more flexible of the two. If the 6ND410 fits your specific design as good or better then go for it. OTOH the 8NMB420 I have didn't knock my socks off distortion wise. Respectable but not great, and a high third harmonic that will probably impact the sound. And that had a shorting ring. Without having tested the 6ND410 I'd guess that the distortion is probably worse than the 6NMB420. Of course the response of the 6ND410 is smoother, so pick your poison. I must say though that both of these cones must be very light, and it's behavior at high SPL would concern me I think. You don't get that high sensitivity for free. I tested a high sensitivity driver from Beyma that would compete with these-impedance looked pretty rough. Theoretical max SPL doesn't mean much when a light cone goes into audible breakup. I don't know that the off axis response will be all that different, the graphs don't even display the same. They are both 6" with similar cones after all. Without knowing what your specific design calls for or what you as a designer considers important I can't really say which is better.

The 6Nd410 was the driver I was concerned about, although it mentions "extremely high sound quality" in the description, which 18sound has reserved for a very limited number of drivers. They must hold it in special esteem if they have given it that title with reference to their other drivers.

FYI, the 6Nd410s impedance plot is an order of magnitude smoother than the 6NMB420.

I think your max SPL calculations are VERY optimistic of the 12NDA520. It's just outside the realm of believability at 100Hz, at 60 Hz there is no way. If subs with 30mm of excursion have a hard time hitting those numbers what makes you think this thing with 2mm of throw is going to do it? At low frequencies drivers are nothing but air pumps. Volume of air moved is what matters, not sensitivity or anything else. So matching these to a 102dB/watt mid is going to be more involved than you think. Are you using active or passive crossovers? With passive you're looking at more than one or two of these to match the 6ND410, at least if you are looking for a decent bass response out of them. Personally I'd go with a mid with a stiffer cone like the B&C 6NDL38. It would be better behaved, would cross easier to most PA woofers, and the sensitivity hit would be acceptable.

Just my .02

I would only use this driver as a midbass/lower midrange with a hpf at 100 or 150hz. As I mentioned earlier, it seems you'd only be able to exploit the advantages of their design by restricting its bandwidth (just as we use severe lpfs on metal coned drivers, except a hpf in this case), otherwise there are probably better choices as you had suggested.

I don't have a project aligned for either of these drivers, just found their specifications impressive and was wondering if there was any real-world experience that corroborated their claims of high performance.