Popular MTM projects

[jmar]

I've decided to build an MTM system.

I'll be using a subwoofer along with an active crossover and 3 separate amps,
one for the mixed mono sub -- one for the MTM lowmid and one for the highs.

I'll also be using a pair of Vifa tweeters that I already have and love -- the D27TG-05 which has an SPL of 91db.

I'd like a bigger sound than what 6.5" woofers can give, so I was thinking dual 8", and prefer sealed enclosures to vented -- with the subwoofer, I may be fine as far as low end.

So, can anyone point me to some dual 8" designs that will do the trick?

---Thanks.

[DcibeL]

In general, for an MTM design to work well, the mid-tweet crossover should be as low as possible, and the spacing between mids and tweet as short as possible. This means an 8" driver is not a very good choice.

If using a subwoofer, you'll have plenty of bass extension with 6.5" drivers in a vented cab. Sealed may work as well if you have an active crossover cutting the bass to them.

[jmar]

Yeah -- you beat me to self replying to my post -- after thinking, I really would like to do 6.5" woofers instead.

Even if I could do 8" in an MTM -- way too much low end.

So, I do see some projects on the parts express site and a few others.

I will have a lot of control over my components with an active setup but I wonder what would be a good match for woofers with Vifas?

They're 6 ohm which is kind of weird but that gets me closer to the 4 ohm that 2 woofers in parallel would be.

So, the idea is to get the 2 woofers and the tweeter as close to each other as possible? I thought there was more to it than that because I've seen so quite a few MTM designs where they were actually very distant.

I thought there may have been some sort of formula involved based on driver parameters? But guess not?

[planet10]

Originally Posted by DcibeL

In general, for an MTM design to work well, the mid-tweet crossover should be as low as possible, and the spacing between mids and tweet as short as possible. This means an 8" driver is not a very good choice.

Unless you are going to use something akin to an FF85 as a "tweeter". My Silver Flute/FF85KeN MTM is approaching the top of the queue.

dave

[thunk303]

Hey Jmar.

After building my first set of MTM using Vifa xt25 and Peerless 850439 I have discovered that the lower I can cross the tweeter over the better.

When crossed at 2.5k they had no life/image/cohesion. At 2k they rock, so I'm going active and heading lower asap.

I cant recommend a tweeter with low Fs/distortion and high order crossovers enough for this design. The XT25 sounds good but can be hard to work with.

Its taken 12 months to get my MTM's making great music, if i had to do it again i would select the best drivers for the design, not the ones i like

Best regards.
Dean

[jmar]

That is sure a low crossover point for any tweeter -- my Vifa has response down to 2500 hz so that could be a problem?

Maybe I should reconsider an MTM.

The only reason I was thinking along these lines was it creates one less amp for my active crossover situation because a midrange driver won't be there and the only designs I see using dual low/mid woofers are MTM.

I want more power handling capability and a "bigger" sound than a simple 2 way system.

I would like to see the plans for the "Silver flute" if you can give me the link.

Well -- anyway, haven't built a speaker in a long time and want to do it right this time.

It's a world of contradiction as always --

Full range drivers in ridiculous enclosures, line arrays, tweeter arguments.

What are "some" of the CRITICALLY acclaimed projects on DIYaudio?

Not any 5 - 6' tower systems or craziness.

Here is another MTM I ran across (and it uses a Vifa) --

DIY Vifa MTM MG18 XT25 Speaker (wonder what this is all about?)

[DcibeL]

Originally Posted by planet10

Unless you are going to use something akin to an FF85 as a "tweeter". My Silver Flute/FF85KeN MTM is approaching the top of the queue.

Yes, of course. The OP had mentioned a Vifa tweeter, hence my comment.

What is probably more accurate, is "The lower the crossover point, the less important the distance between drivers is".