HiVi M-12 Question....

[Stevepaul]

I have a question about the Hi-Vi M12 woofer.....

I have an Eton 4" mid that measures 89-90db sensitivity. I also have a Morel MDT40 tweeter (one of their very small neo tweeters) that is also in the 89db sensitivity range. I have a pair of 'Woodstyle' 2.6 cubic foot tower enclosures that would just fit the M12 woofer on it's baffle.

My thinking is x-over points around 450 and 2800....with 24db L/R slopes. With the M12 having a sensitivity in the 93-93.5db range, that gives an opportinity to keep overall system sensitivity in the 89-90db range after 4db of BSC (which is all I really need in my family room). Plus, the small Morel tweeter face plate allows me to get a Center to Center distance between the mid and tweet of only 3.8".

Is the M12 good up to 450hz with 24db slope? Does my plan pass the sniff test? Are my xover points reasonable?

(I live 10 minutes from Meniscus Audio and they have all the measurement equipment and would help me design the crossover...I get along with them pretty good and get great service from them...I would order the M12 from PE)

Any thoughts? (the M12 is just so sexy!!! :leghumper: )

Thanks,
Steve

[JonMarsh]

Steve,

Checking out the M12 is one of those things that I've always wanted to do, and never gotten around to. It SHOULD be just fine up to 450-500. Sensitivity should work out well.

Which Eton do you have for the mid? The 4-300? One possible drawback to a 2800 Hz crossover point is center to center spacing- should be a bit under 5" at the most, and that's not easy to do - looks like you can manage it with that tweeter, though. I'd also look at the 3rd harmonic plots, see where that starts rising, and if you know of any ETC data, that would be worthwhile to consider also. I'd really expect that you'd be best off more around 2.2-2.4 kHz if the tweeter is OK there. Just my gut feel- feel free to ignore. A four like that may go high enough, but then it only has a linear excursion range of 1.5 mm, so the going low may be more the problem, if you want it to keep up with the HiVi 12. I'd be inclined to go with the 5-880 myself in such a configuration (well, actually I'd probably go with a six and a larger tweeter, and a lower crossover point for the 12). Just my 0.02.

[Stevepaul]

Thanks Jon...

I was trying to utilize drivers and enclosures that I already have around the house. Normally, I wouldn't use a 4" mid (unless I MTM'd them)....and I agree that a 6" mid would be a better match to the M12 12" woofer, along with a quality 1" dome. I actually have 4 of the RS180's at the house...actually forgot about those!

M12, RS180, and maybe the new inexpensive metal dome from Seas....now that sounds like fun...xover of 200hz and 1400hz Although, a 200hz passive is going to be expensive!

The Eton that I have is the 4-300. I don't have any measurements on it..except what is on the corporate spec sheet. I have worked with Meniscus Audio with these in the past and we MTM'd them with a Esotar 330d at around 2800hz. BSC wasn't correct though as they sounded a tad harsh. I may just end up using the Etons as little computer speakers with a little 3/4" dayton tweet.

I am going to have to think some more 'bout this.

Thanks again.
Steve

[JonMarsh]

Thanks Jon...

I actually have 4 of the RS180's at the house...actually forgot about those!

M12, RS180, and maybe the new inexpensive metal dome from Seas....now that sounds like fun...xover of 200hz and 1400hz Although, a 200hz passive is going to be expensive!


I am going to have to think some more 'bout this.

Thanks again.
Steve

Now, that combo sounds like it could be a lot of fun! You might still move up the crossover a little higher (250?), just to make it easier electrically regarding component size; Id play around with that to see how it looks. One possibility would be using theh RS180 in a pretty narrow, smallish sub enclosure tuned at the 100 Hz area; this may simplify the HP crossover, then see if you can do something like Wilson does with the LF crossover initially slow and filling in the BSC. But, apart from cost, with that approach, I would be tempted with two RS265HF on the bottom end- making the whole thing something of a mini Maxx. That would be pretty killer... and I will be measuring the RS265HF in detail soon.

~Jon

[AJINFLA]

Hi Steve,

I wish there was more data out there on the Morel drivers. Their tweeters share technology with Dynaudio and Scan Speak. Thats a good thing IMHO.
The MDT40 might be ok crossing lower than 2.8k, maybe as low as 2k or so. I really can't say for sure. Maybe Meniscus could do some distortion testing for you (us) . Here is my reasoning. Mark K's test of the MDT30 showed a tweeter with respectable numbers as far as crossing at 2k or possibly even slightly lower. I believe (and please correct me if I'm wrong) the MDT39 is the neo version of the MDT30. The MDT40 simply has the Hexatech VC, but is otherwise the same. I know I'm extrapolating quite a bit here :W , but hey, it could be close.
Bottom line is, how does it sound? Have you used it previously?

Cheers,

AJ

p.s. Anyone want to start a "pay for it you got it" distortion testing service? Might work :T

[Stevepaul]

Hi AJ,

I used the MDT39 (with some Audax 6.5" aerogels) in a 2-way about 3 years ago. I didn't compare the system to anything else...as they were for a HT system I was working for someone else. But, I will say that they sounded excellent....for lack of a better descriptor!

Their small faceplate along with the chamber and decent motor make it a nice candidate for any xover points above 2500hz....as it allows the closer Ctr-Ctr spacing requirements.

If you like the sound of the more standard Morel tweeters....you'll like the sound of their small faceplate tweeters (the ones with the rear chambers).

Steve