on Sale - $55/pr (drivers & XO)

[lostboy77]

Re: on Sale - $55/pr (drivers & XO)

I've just purchased the drivers for the MT version of these and am putting together a cart full of XO parts as well . . . The one issue I am having is that I'm not seeing a 3.3 Ohm 5 Watt resister option for purchase. Will the Dayton 10 Watt work fine in it's place? Also, is there any harm in going with the Dayton Poly capacitors (rated at 250 Watt) rather than the specified 100 watt variants. The reason for the question is that I have free access to the Daytons and would have to purchase the others if these would not work.

These are probably rather noob questions so thanks in advance for your assistance.

[fastbike1]

Re: on Sale - $55/pr (drivers & XO)

Those would be fine. Chris was building to a specific price point. The ohms/farads values are the important ones.

I've just purchased the drivers for the MT version of these and am putting together a cart full of XO parts as well . . . The one issue I am having is that I'm not seeing a 3.3 Ohm 5 Watt resister option for purchase. Will the Dayton 10 Watt work fine in it's place? Also, is there any harm in going with the Dayton Poly capacitors (rated at 250 Watt) rather than the specified 100 watt variants. The reason for the question is that I have free access to the Daytons and would have to purchase the others if these would not work.

These are probably rather noob questions so thanks in advance for your assistance.

[superspeeder]

Re: on Sale - $55/pr (drivers & XO)

Has anyone else tackled a set of the MTMs yet?

[Chris Roemer]

Re: on Sale - $55/pr (drivers & XO)

Has anyone else tackled a set of the MTMs yet?

Although I haven't built (or heard) the MtM version yet, I have fiddled with it a bit since getting the TMs measured at Iowa DIY. I'm getting ready to build a pair (wish I knew if I'd ever see those woofers at $12 again?) and have adjusted the box a little for some 15" high stands that I've got. I'm also increasing the BSC a tad and pushing down a rise around 2-3k with a larger inductor.

I'll probably add the revisions to this thread, soon.

Chris

[lostboy77]

Re: on Sale - $55/pr (drivers & XO)

Is there any problem with down porting the MT. I want to use enclosure dimensions of 6x9x18 and am concerned with the port getting too close to the front baffle.

[brianbunge]

Re: on Sale - $55/pr (drivers & XO)

Is there any chance you'd model the MTM horizontally as well? I'm considering the AviaTrix MT's as skinny towers with the MTM for a center in my bedroom system but if I could do the same thing with these it would save me a lot of money, especially since I already have 3 of the ND20 tweeters. The room is only about 18-20' wide x 12' deep so these and a TB 6" sub would probably be more than adequate.

Thanks,

B

[Chris Roemer]

Re: on Sale - $55/pr (drivers & XO)

Is there any chance you'd model the MTM horizontally as well? I'm considering the AviaTrix MT's as skinny towers with the MTM for a center in my bedroom system but if I could do the same thing with these it would save me a lot of money, especially since I already have 3 of the ND20 tweeters. The room is only about 18-20' wide x 12' deep so these and a TB 6" sub would probably be more than adequate.

Thanks,

B

Well, successful horizontal MTMs have to basically cross an octave LOWER than one with vertical orientation or a TM, due to lobing issues. IMO the ND20-6 just won't go that low without a lot of crying.

Chris

[lostboy77]

Re: on Sale - $55/pr (drivers & XO)

Would it be possible to build a variant of these in a small sealed enclosure and still get decent bass.

So far I've seen this done with the 5.25" and 3.5" Daydon ND midwoofers in Curt's AviaTrix and Wolf's "PC" (Perfectly Compact) Speaker by running a large cap in series with the midwoofer. Just wondering if something like that would be possible here with the 4" variant.

[Chris Roemer]

Re: on Sale - $55/pr (drivers & XO)

Would it be possible to build a variant of these in a small sealed enclosure and still get decent bass.

So far I've seen this done with the 5.25" and 3.5" Daydon ND midwoofers in Curt's AviaTrix and Wolf's "PC" (Perfectly Compact) Speaker by running a large cap in series with the midwoofer. Just wondering if something like that would be possible here with the 4" variant.

You can do whatever you want, but a quick sim in WinISD shows an F3 in the high 30's in a Vb of 0.30 cf (which is not all that large), VS. an F3 in the high 80's in a Cb of 0.15. That's a trade-off I'D never be happy with.

If I NEEDED a smaller box (say, 0.15 cf), I'd vent it and use the ND90-8 for an F3 in the 40's.

Chris

[brianbunge]

Re: on Sale - $55/pr (drivers & XO)

BTW, Chris, what is the crossover frequency? I've skimmed back through the thread and don't seem to see it mentioned anywhere.

[Chris Roemer]

Re: on Sale - $55/pr (drivers & XO)

BTW, Chris, what is the crossover frequency? I've skimmed back through the thread and don't seem to see it mentioned anywhere.

It's right there, on the box drawing (along with my WT3 parms). Fc near 4k. The ntn is a little lower.

Chris

[superspeeder]

Re: on Sale - $55/pr (drivers & XO)

Although I haven't built (or heard) the MtM version yet, I have fiddled with it a bit since getting the TMs measured... ...I'll probably add the revisions to this thread, soon.

Sounds great Chris! Will these improvements also include the extra tweeter protection?

[brianbunge]

Re: on Sale - $55/pr (drivers & XO)

I'm really thinking this design is gonna be my choice for the bedroom system. Even with the deficiencies of the MTM as a center, I don't know that it'll be such a huge deal for the bedroom. Either that, or maybe Chris will model a 3-way WT/MW with a pair of the ND-140's flanking the TM! I love 3-way centers! ;)

[Chris Roemer]

Re: on Sale - $55/pr (drivers & XO)

Sounds great Chris! Will these improvements also include the extra tweeter protection?

Yes, but it's not really protection, with just a cap (and L-pad) there's a bit of a cliff at the tweeter's bottom end. A 2nd order (adding the coil) makes for a nicer rolloff and better integration with the 105.

BTW, someone ran these for HT lately, and the 105s "snapped" a dozen times or so, apparently w/out damage. At their rated 30w, they stay below their 10mm Xlim down to about 38 Hz or so, but send them some 32 Hz LFE stuff, and they cry, but the tweeters are happy.

Chris

[lostboy77]

Re: on Sale - $55/pr (drivers & XO)

Ok, I've purchased the drivers and XO parts and am starting my enclosure build. I'm going with .32 ft3 enclosures (after the XO, drivers and port tube is added I think it will be closer to .3) and am making it a little wider and not quite as deep to better fit my shallow desk.

My question is regarding driver spacing. I'm considering using a baffle cover using a 6" wide by .5" thick piece of solid red oak routed on the backside to allow for the surface mounted driver (going for a "rear mounted" look without actually rear mounding the drivers). I was wondering if the specified driver spacing is the furthest distance or if they can be moved a little further apart to accommodate the .5" round over I will be using on the driver holes.