ml tqwt with unknown driver

[stevodude]

Hi guys, I like the shape and stance of this enclosure:

mjk's project 2 ML TQWT -


http://www.quarter-wave.com/Project02/Project02.html

Now the nearest info I could find on the driver was this sheetclick on it and zoom in in picasaweb)



and another that say Fs was 55Hz.

Will this go in one of these? I mean I'm going to give it a go anyway, but I'm not sure of the dimensions of the enclosire, nor the position of the driver.

Cheers, stevo.

[Scottmoose]

Looking at that, I have my doubts. That page indicates that they were used when new in slotted (nee ~resistive vent) boxes, suggesting to me they're a high[ish] Q design. If so, you'll likely get an uncontrollable bass response as-is.

FWIW, I just ran a check on that box with the high Q Visaton B200 just to see what's going on with a unit of that sort. As-is, response is what you'd expect (vile). However, if you damp / stuff the entire cabinet, and stuff the vent too to make it a quasi aperiodic alignment (while keeping the aesthetic of the cabinet), it does passably enough down to about 50Hz or so.

[stevodude]

So, basically I'll be just using the design as asthetics only, and won't be helping the driver.

and is probably better of in a 2 way simple sealed/small ported enclosure being a high Q driver? correct?

can't be any worse than my beer box speakers LOL...

[stevodude]

back on the transmission line enclosure, This is a quote from another website that I found someone new some information about the driver:

dr.ido
04-01-2006, 11:13 PM
Here in Australia in the 60s and 70s a common speaker was sold under several different brand names (Kriesler, Pye, HMV, and probably others), but they were all basically the same. A single Magnavox 8WR or Rola C8MX (which were basically interchangable) in a ported box. The exact dimensions escape me at the moment, but they were all the same size. Only the finish, grill cloth and badges differed.

The Magnavox 8WR and Rola C8MX were both 8 inch drivers with 2 inch whizzer cones and pleated paper surrounds. Early versions have AlNiCo magnets, later versions are ferrite. AlNiCo versions are usually 15 ohm, ferrite 8 ohm, but some oddball ones show up (3.5 ohm Rolas and 27 ohm Magnavoxes).

I find the high end rolled off too early, they do need a super tweeter. In the slim line cabinets they are usually found in they lack bass, but they improve dramatically in a larger cabinet. They supposedly work well in a transmission line, but I have never heard them in one.

[stevodude]

OK, I am going to scrap that idea (again :-) )

so simplest build with best wide audio range for a pair of fe206e 's I can pickup from local company majormusic.com.au for $230 delivered for the pair.

I like a bit of bass, my hearing is probably half shot from the early eight's and being a drummer giging for 10 years, but I can still tell bad from 'thats nice' /nods head...

room is 3 meters wide (2.2mtr anamorphic screen), 9 meters long seats 9 people :-), and about 2.6 meters to ceiling.

music is pretty much mainstream rock/pop, small percentage classical/country, mostly David bowie style music:-)
amps are currently a JVC surround 70w x 6 , 70's JVC transistor amp 30 x 4, and a couple of diy tripath amps ( various stages of build).

Current mains are some floor standers, base reflex 3 x 8" bass , 4" mid 1" tweeter's which do great for moovies with plenty of punch for the video noise and bass. but want to be able to switch amps and listen to some nice clear music...

Metronome
simplest to build, 4 sides, top bottom, port. - can't find a plan for the fe206e

BIB
the calculator doesn't have the fe206e listed..

or bruce

price wise the metro's or the BIB would use about the same amount of wood and probably time aswell to build. The Bruce using more wood, and more time/effort to build.

I like the metro shape, the others are a bit square without doing something fancy with the shape.

Considering my wife works when I'm home, so shortest build period is not a requirement, but a preference :-)


please help me decide on a solution

[AdamThorne]

The metronome is simple conceptually, but depending on how anal you want to be about your construction making all those non-parallel cuts can be a PITA.

I'd bet the BIB is a simpler build.

[Scottmoose]

Originally posted by stevodude
Metronome
simplest to build, 4 sides, top bottom, port. - can't find a plan for the fe206e

Use the 207 dimensions. You might need to add more correction. You might not.

BIB
the calculator doesn't have the fe206e listed...

Yes it does. And anyway, that's why they call them calculators: you can enter specs into both sheets yourself you know -all you need to do is type in the driver Vas, Qt & Fs.

Originally posted by stevodude
or bruce

Decent but superceeded as-is by Chang now.

If you want quick / simple & have corners to load them into (they're corner horns) then the BIB would seem to a bit of a no-brainer.

Alternatively, as you like Martin's ML TQWT, why not use that. Using accurate 206 specs (average of 8 drivers) measured by Dave, from a technical POV it should work OK in that box, no modifications required, as shown below. I think it should squeeze in, physically.

[GM]

Greets!

FWIW, I had some experience with the Magnavox circa '67 in a factory cab of ~8 ft^3 combined with a 2.2 uF capped off HF horn. It was open at the bottom and spaced up off the floor with 1/4" tall x 1" diameter furniture tacks according to my notes. This was the cab that taught me two valuable lessons WRT cab static and acoustic resistive mass loading when I 'cloned' it as a ~48" tall floor-stander by omitting its 3/4" thick slate top in-lay and naively converted its floor slit vent into a standard baffle thickness rectangular shaped one higher up.

What started out as a curiosity about how an acoustically too short TL might affect vent loading with cheap 'throw away' drivers turned into a minor cornucopia of speaker design insight that's dictated my cab layout preferences ever since.

Regardless, these I used are best suited for low output impedance, AM/FM, vinyl, systems of the day, so for today's wider BW sources it ideally needs a sub system and more extended super tweeters.

GM

[stevodude]

Thanks everyone.

I've done a basic model of the metronome for the fe207, which will fit the fe206e in no probs.

I've modeled it on 3mm Plate steel ( as I have quite a few large sheets lying around over at the farm shed. ), so once I finish weilding up my ride on mower , I'm going to build a pair of steel metronome's , if anything it will give me some more experience with the weilder. :-)

I've seen a BL horn built out of steel, and i want to give it ago, as all it will take is my time for welding, no other cost, so nothing to loose.

I've uploded my metronome sketchup into 3d warehouse if anyone wants it. Dimensions I just checked are slightly out :-/ but only by a couple of mm, soe probably won't make any difference.

Port I guess will be 3" (75) x 3"(75) long?
and basically line all the walls with some sound deadening, may not need any cotton fill?

[stevodude]

oh and the BIB won't be any good as they won't be anywhere near the corners as I have the wide projection screen up to 1/2 meter off the wall and bass traps behind the screen and the theatre speakers in front of the edges, so the new full ranges will be infront (outside) the theatre speakers. (ie pretty close to the side walls).

next weekends project is cut the steel up for fitting and sand blasting, then tack welding. Then I'll have a go at a 2 pack gloss black.
they are going to be quite meaty looking I do believe