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Date: December 05, 2005 at 20:41:18
From: ILYA, [c-67-168-255-64.hsd1.or.comcast.net]
Subject: Manifold Technology: EV MT-4 & MT-2, etc

URL: MTL-4 Datasheet


Lately, I've been getting interested in Manifold Technology for PA use... It was first pioneered by Electrovoice in the late 80's... They made two systems worth mentioning : MT2 (with 2x 18's) and MT4 (with 4x 18's)... There isnt much info out there, so i thought i'd summarize and ask some questions and opinions...

These systems were mainly designed for high SPL, but not extra-deep bottom end. They are great for providing MAD bass "where it matters" - which is in the 50-80Hz range, maxing out around 60hz. They are basicly useless below 40Hz, but people say they can be x-over at 37-38Hz... I think they were primarily created for space-saving stacking designs, to deal with the directivity issues (cluster beaming) that arise when you stack a Bunch of speakers together.

MT4 consisted of MTL-4 bottoms and MTH-4 tops.
MTL4 used either an EVM-18B or EV DLMT-18 drivers.
MTL2 used EVX-180a drivers.
Constructed with 13-ply birch wood.

MTL-2B also came in two more versions: PI-218T and DLM-2181. EV also produced a decreased-performance half-sized "trap" version, MTL-2BT, which later became the EV X-Array Xb sub, and later was re-introduced doubled in size again, as Xds sub.

According to EV, a block of 2 MT-4's (H+L) powered with 10kW will produce 140db at 1 meter. I found some Michigan sub shootout results that compared MTL2's to Bassmax, LAB sub, Servodrive, etc, and they found that 2x MTL2's produced 126.8db @ 47Hz, -6db, 12 feet... Overall, the MTL's got beaten by those other monster subs, but just the fact that they were in that competition is a good enough reason to wunder about them... theres also a freq responce graph that compares Tuba 30 by Fitzmorris (on his site) with an MTL4...

There also are some other similar box designs, such as EAW SB1000z(Ri), TCS 2800, Yorkville TX-8, SBX 220, Apogee FH-18, etc...

now,

I need to build a PA capable of HIGH SPL levels for events under 1000 people. It will be used mostly for House music and Hardcore Techno in club-like settings, with an occasional outdoor. It needs to fit in my fullsize Chevy van. I have limited time and resources to dedicate to this project, therefore it must be easier to build than LABsub or Tubas, and cheaper than ServoDrives or Bassmax, yet able to come as close to their performance as possible (forget about below 40Hz). Any other design suggestions welcomed.

I have an active 4-way x-over for this project, and I am planning on running total of EIGHT 15's or 18's with eight Monoblock 600W 8-ohm amps.

I found ONLY ONE plan for MTL-4, included here.
Also included is a link to a pdf MTL-4 manual.

I am very interested in other Manifold Technology plans and clones. There are supposingly many out there, i just cant find any info on those...

PLEASE POST UP SOME LINKS OR PLANS!!!

I am also very interested in scaling the MTL-4 box down to fit 15's, so that it fits through the doors better. I dont know much about "scaling" process, so any input is great. I am guessing that since 15/18 ratio is 0.833333, then all the box dimensions will get scaled by multiplying by that number. But i am not sure about that.

I would also be interested in possibly "squishing" the box with the 18's in one dimension, for the same reasons... how would i go about that?

Also, interested to know, just what "kind" of the box the Manifold designs are... are they 6-th order bandpass variation or what??? Also, how can manufacturers claim to have Manifold design with just one driver per box???

Also, i cant quite make it out from the drawing just how the port system in MTL-4 works... i obviously will need to understand that if i want to build them...

Any suggestions on what would make a good driver for such a box??? Brands-vise, and parameters-vise...


I am sure i will have more questions later as well :)


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