[cman]

when I first found these I was so extremely excited… I was getting ready to pull the trigger on a pair… sensitivity is not fabulous, but for how much xmax it has I figured I could live with it.

But after seeing the voice coil review no effing way… The frequency response is ridiculous… The sensitivity on the low end ( where I would be using this and I think most users would be since it has so much excursion ) is terrible! It looks absolutely nothing like the spec sheet from Misco… Which is a shame because everything else is pretty dang good. I can’t believe they own a klippel machine and build their drivers in house and produced something with a frequency response that looks like this...

i’m not an expert driver designer so maybe I am misguided in my thoughts but it just doesn’t look very good to me… especially after reading Miscos spec sheet that really gets you hyped up about the cutting edge engineering…

 

[cman]

The thing to keep in mind when looking at measurements by voice coil is the they are taken in a speaker enclosure, not IB like a company would show. In the case of this driver, it was a 8x17" baffle. This means baffle step is a factor. If you don't know about baffle step, it is essentially a 6dB loss at low frequencies because after the wavelengths get longer than the enclosure is wide, the energy starts to eminate backwards as well as forward. So, when comparing the voice coil measurement to the manufacture's you have to assume an additional 6dB that gradually decreases as frequency rises. In the case of this driver, it fill in quite nicely to the desired response. Additionally there is some diffraction that will mess up the response as well. Namely at 800hz, that small bump, and some other stuff higher in frequency that is being masked by smoothing (1/6th, I hate that they do this) and breakup.

So overall, I'd say that the manufactures measurement is quite close to what vance measured and I would actually trust it more in this case due to the lack of smoothing used. Regardless, the response in your car will vary greatly due to the environment it is in, but as a sanity check, the supplied measurements are good.

Most car audio products I've seen inflate sensitivity greatly, either measuring it via 2.83V (not lying, just misleading IMO) or just choosing a random spot in the response (lying IMO). It should truly be done based on 1watt and based on the t/s parameters. If you want the best idea of the actual sensitivity of a driver (compared to other drivers, not real world), using a program like winisd or hornresp is your best bet. Low frequencies don't vary from driver to driver as high frequencies do. If a manufacturer posted spec varies from what a program says below about 400hz, then the driver has some sort of resonance, or the company is lying about something.

great information! thank you


i am fully aware of the sensitivity inflation, I try to get T/S specs on all my drivers and put them into WinISD so I can see the true one watt one meter SPL#

car audio manufacturers seem to lie about more stuff than they tell the truth about.


i’m going to do some more research into what you explained… I was extremely excited to try a pair of these until I saw that measurement… I figured I would cook the voice coil or enter compression from heat before I reached my desired output level, since it’s not a big overhung coil… it’s an XBL 2 design so I would assume the coil is not as tall… although I might have been completely wrong in my assumptions, especially if their measurements are not free air like the ones I am comparing to…

 

[cman]

Well it's hard to say for sure how compression would actually look without testing being done, but I imagine since they do have a klippel and it appears to have been used effectively (at least for this driver), it's probably safe to say the power handling rating is pretty spot-on, and that wouldn't really change if the coil was longer/larger. The smaller coil may use thicker gauge wire than a conventional coil, which would help explain the low fs. I'd say as long as you were using it within its specs you'd be fine.

I'd still probably recommend something else in the case of a midbass though. Long throw is cool and all, but I would much rather use a woofer with higher sensitivity and 5-6mm xmax. Chances are if you are crossing at around 80hz to a sub, that's all you'd need. I believe these drivers were probably envisioned for home use with their fs and qts. When put in a medium sized bookshelf enclosure they can probably provide surprisingly strong bass compared to other options on the market. In a car though, unless being run full range or crossed unnecesarily low to a sub, you're probably better off with something else. Though I am still very impressed that they are able to ship something that is assembled in Minnesota, has a cast basket, and actually uses the xbl2 name for the price they do. If they come out with some drivers that are more useful for my situation, I'll definitely be the first to grab some. I imagine shipping wouldn't be too much as I live like 5 miles away. Maybe they'd even let me demo some lol.

Yeah I do cross at 80hz..sometimes even 90hz.. I like to play my sub as high as possible until I run into response issues from the cabin or localization on the sub.. just because the sub does a fabulous job at reproducing those frequencies.. so you are probably right, i doubt i would ever be using more than a few mm of xmax.