Discussion about MCM kb series.

duanebro

I would like to build a 3way design with the kb series 8" and kb mid. I like the 3" as it seems easiest to work with. The 4" has some wierd fr issues. I have two questions to start with about this. Plus I would be interested in others thoughts and questions of the new kb line.

First, can the 3" mid work with the 8" woofer once baffle step is taken into account?

Second, how would you use the 4" driver in a design?

Looking forward to your thoughts,
Duane

jr@mac

Not sure the 3" offers the sensitivity to keep up with an 8" unless you bank on some passband boost - not unheard of in smallish 3-way designs.

Keep in mind, the rise in response on the smaller KB series drivers is actually evidence of a good motor - rising Le usually tanks the top end on many drivers, and on certain drivers, like most of them equipped with a large voice coil, (HiVi, Morel, Dynavox, Dynaudio, Esoteric), the Le attributed to the large coil actually hides distortion inducing breakup modes - but distortion doesn't necessarily get buried (for evidence look at nearly every driver made) - except when care is taken to control distortion induced by rising inductance. In the case of the smaller KB drivers they have an underhung motor (short voice coil = less inductance) a copper cap (shorting ring = less inductance) and a pole mounted aluminum phase plug (another shorting ring = less inductance). Throw the well ventilated frame into the mix, and well behaved cone (yes - well behaved, the rise is controlled and does not exhibit any breakup) and these drivers will be worth the extra crossover work. My educated, informed, and well thought out guess (hopefully confirmed today as a matter of fact - time crunch) that these will rate very, very, very high on the performance scale at any cost.

isaeagle4031

Ive got the drivers on hand for a 3way. 8, 4, and tweet. Just using sims, they look very promising. The FR of the 4 doesnt look bad at all. 

The 8 i think can actually work well in a 2way given the right tweeter. Ive got a pair of TB 28-537SH that I may give a try. 

The 3, 4, and 5 are definitely midrange drivers. As JR said, the inductance is well controlled and the cone is very well behaved. I posted imp data on the drivers i have on hand in another post. The profiles show no cause for concern 

duanebro

isaeagle4031 said:

Ive got the drivers on hand for a 3way. 8, 4, and tweet. Just using sims, they look very promising. The FR of the 4 doesnt look bad at all. 

The 8 i think can actually work well in a 2way given the right tweeter. Ive got a pair of TB 28-537SH that I may give a try. 

The 3, 4, and 5 are definitely midrange drivers. As JR said, the inductance is well controlled and the cone is very well behaved. I posted imp data on the drivers i have on hand in another post. The profiles show no cause for concern 

Thanks. What tweeter are you using for the 3way? I could buy the 4" and, if I can't figure out the xo, just ask you nicely for help... 

duanebro

Beston RT003C Round Ribbon Tweeter

I'm thinking this could make a great tweeter for this 3way build. Though it does cost more than the MCM tweeters...

PWRRYD

That Beston sounds very nice when you cross it over high enough.  Wolf used it in his Stance project.

duanebro

PWRRYD said:

That Beston sounds very nice when you cross it over high enough.  Wolf used it in his Stance project.

That is where I heard it. It made a lasting impression. Which is why I'm still wanting to use it...

isaeagle4031

duanebro said:

isaeagle4031 said:

Ive got the drivers on hand for a 3way. 8, 4, and tweet. Just using sims, they look very promising. The FR of the 4 doesnt look bad at all. 

The 8 i think can actually work well in a 2way given the right tweeter. Ive got a pair of TB 28-537SH that I may give a try. 

The 3, 4, and 5 are definitely midrange drivers. As JR said, the inductance is well controlled and the cone is very well behaved. I posted imp data on the drivers i have on hand in another post. The profiles show no cause for concern 

Thanks. What tweeter are you using for the 3way? I could buy the 4" and, if I can't figure out the xo, just ask you nicely for help... 

The 53-5165 tweeter from mcm. The beston would make a good choice as well. 

duanebro

I ordered a set of 4" and 8" along with the small aluminum tweeter. Not planning on using the tweeter with the kb drivers, but it could end up in my car...