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Homebrew MTMs

Horn Head

Horn Head

Super Member
Just finished these MTMs....after about five years of sitting around half-done.

Have some cheap Infinity woofers and generic mylar tweets. Only a cap for the crossover.

These aren't very advanced and there were no calculations or design specs going into these - other than ensuring I wired the woofs in series to get 8 ohms. Just wanted to finish them up to put out in the yard sale next weekend.

Hooked them up and was pleasantly surprised! They actually sound pretty good. No bass to speak of but midrange presence in spades. And surprisingly, the tweeter is pretty controlled. Hooked up a passive DVC sub handling sound below 100hz and it blended perfectly out of the Pioneer SX-1080.

Funny, almost don't want to ditch them now....but they must go. Probably over 30 pairs of speakers around the house and many good ones. So these will get sacrificed for space. Will be neat to see them go though - that means someone else likes them!
 

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Gee, I clicked on this thread hoping to see how you went about MTM crossover design... guess I came to the wrong place! ;)
 
dumptruck said:
Gee, I clicked on this thread hoping to see how you went about MTM crossover design... guess I came to the wrong place! ;)
Click to expand...

Sorry.....Yep, nothing fancy here (that's why I was surprised about the sound quality - shouldn't sound as smooth without a real crossover.)
 
Horn Head said:
Sorry.....Yep, nothing fancy here (that's why I was surprised about the sound quality - shouldn't sound as smooth without a real crossover.)
Click to expand...

Sometimes, simple is very good. A couple reputable manufactures I've heard of have taken a similar approach with a "one-cap only" x-over setup for some very nice speakers...all depends.
 
That is what I am thinking. The simple x over is what is surprising you. Check out the Decware sight. That is all this guy uses or none at all on single drivers.
 
rifftrax said:
Sometimes, simple is very good. A couple reputable manufactures I've heard of have taken a similar approach with a "one-cap only" x-over setup for some very nice speakers...all depends.
Click to expand...


Yep, Reference 3a is known for not using crossovers on their mid ranges or woofers...just a single cap on the tweeter and they are among the finest speakers anywhere.
 
Hmmmm.....an accidental genious. What a great role to stumble into.

Didn't know any 'real' speakers just used caps. Will continue to play them for the rest of the week to make sure it's not my ears (and ego) playing tricks on me.....
 
Horn Head said:
Hmmmm.....an accidental genious. What a great role to stumble into.

Didn't know any 'real' speakers just used caps. Will continue to play them for the rest of the week to make sure it's not my ears (and ego) playing tricks on me.....
Click to expand...

IIRC OLA and smaller advents just use a 1st order high pass (capacitor) crossover--no low pass filter (inductor) on the woofer....

I think my AR18's are the same way.

the AR 2ax's (3-way) use an inductor on the 10" woofer for a low pass, and only capacitors on the mid & tweet--no inductor on the midrange to make a true band pass filter.
 
Just a quick update. Played these over the past two weeks (didn't get them sold at the yard sale) and man, am I pleased. Absolutely no technical thought went in these. Constructed solely by eyeballing what might look good.

Hooked them to the Pioneer SX-1080 with a DVC passive sub on the 'B' terminals and blew me away. Stayed up past 3:00am last night listening to vinyl on these with no fatigue.

Sometimes you just get lucky I guess.
 
I was about to ask what Secret Components you used, but then I reread the OP:
Have some cheap Infinity woofers and generic mylar tweets. Only a cap for the crossover.
Click to expand...
Other than the woofers (they gotta have googlable part numbers on the back, don't they?), we may never know...
 
I heard them. It's not him blowing smoke, they are actually that good. Chuck Mangione in that room off vinyl sounded much better than one would expect, could have listened with pleasure for hours. Synergy and simplicity can be your friend.
Probably gonna be keepers now.
 
Second Order (and higher) crossover networks while absolutley needed with some drivers, can also add unpleasant phase errors and distortion. It's one of the things that keeps me coming back to simple first order two-way systems and full range drivers.
 
benb said:
I was about to ask what Secret Components you used, but then I reread the OP:

Other than the woofers (they gotta have googlable part numbers on the back, don't they?), we may never know...
Click to expand...

Again, bought the drivers several years ago from PE. Here's what there are:

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Vifa Infinity - 299-492

You are looking at a paper cone midbass driver with silver cosmetic polymer frame, specially treated foam surround, and a bucking magnet. Looks to be originally intended for use as a midrange driver. A special mounting flange will allow the driver to be flush-mounted while still keeping a small lip covering the front of the cabinet. The 1" voice coil diameter with vented aluminum former plus vented pole piece assures that this will offer good power handling. Limited supply!
Specifications: *Power handling: 50 watts RMS/100 watts max *VCdia: 1" *L1: .40 mH *Znom: 6 ohms *Re: 4.25 ohms *Frequency range: 110-6,000 Hz *Fs: 110 Hz *SPL: 88dB 2.83V/1m *Vas: .07 cu. ft. *Qms: 1.63 *Qes: .60 *Qts: .44 *Xmax: 1.5 mm *Dimensions: Overall Diameter: 5", Cutout Diameter: 4", Mounting Depth: 2-3/4".

*************

Tweeter Onkyo 780

Standard 3/8" Mylar tweeter element with phase lens. Perfect for small compact speaker projects. Rear mounting may be required due to terminal locations. Limited quantities.

Specifications: *Power Handling: 20 watts RMS/40 watts max *VC dia: 3/8" *Znom: 6 ohms Re: 4.10 ohms *Frequency range: 6,000-20,000 Hz *Fs: 4,200 Hz *SPL: 87 dB 2.83V/1m *Driver Dimensions: Overall Diameter: 1-3/8", Cutout Diameter: 1-1/4", Mounting Depth: 5/8".

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I remember the woofers costing about $4 ea and the tweeters were like 25 cents each. Picked up a whole bag of those tweets...
 
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