Stephens Trusonic 120cx speakers - Best type of enclosure design?

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Hi All

I have a pair of lovely trusonic 120cx, man they are sexy looking speakers!

There isn't a great deal of information out there about them especially there parameters.

I have a dayton dat v2 which i can use to get some speaker parameters, how accurate this will be i am not sure but it's a starting point.

Anyone got an idea on enclosures for this?

I was hoping for a few ideas:

A nice onken designed enclosure would suit these nicely, maybe a back loaded horn? I think i've even seen these used in a Karlson type design.

Any information or advice is always appreciated!

Thanks


trusonic.jpg

onken.jpg
 
Great drivers. Edge-wound voice coils. Feather-light cone assembly. Good magnet motor. Don't touch the surrounds - DAMHIK.

I can't think of any reason you'd need to know the T/S specs. They have wonderfully low resonance and will be great in a largish sealed or leaky-box enclosure.

B.
 
Leaky box like a goodmans aru type enclosure? Suprised I cant find any info on box designs for these drivers. Was hoping for a more exotic type enclosure, instead of guessing the dimensions I'll have to source or test the speakers to get some TS specs.
 
+1 although I thought my plain-language description was all that was needed. Not logical to "design for" as GM suggests than simply to make biggest box that's feasible and get the most you can.

I have a Stephens 150w about 60 years and have mounted in all kinds of ways*, finally 17-foot labyrinth last year (exotic enough?).

17 foot pipe sub 12-230 Hz ±5dB

However, almost certainly wise to toss the stock crossover and L-pad and go to DSP (OK, almost anything fresh).

I'd start with some impedance runs (needs no mic) and also mic runs to see how tweeter behaves. I am skeptical of accuracy of made-at-home T/S testing.

B.
*absolutely fabulous in a giant open-baffle because the 20 Hz resonance is perfect.
 
Thanks B

I have and use REW with a proper mic, so I was going to do a whole lot of tests just to get some performance readings aswell as the TS measurements (the dayton dat v2 is actually pretty good)

I'll read through your thread for some inspiration.
 
+1 although I thought my plain-language description was all that was needed. Not logical to "design for" as GM suggests than simply to make biggest box that's feasible and get the most you can.

You didn't define 'largish'. Relative to what? Many folks here think 5 ft^3 is unacceptably large whereas this was pretty small for us folks that grew up with speakers 2-6x larger, hence my very 'logical' response.

But all this is irrelevant since the OP has some specific alignments in mind, so, smart guy, design him an Onken, BLH, Karlson or any other technically optimized cab he may show interest in using your way.

GM
 
This was interesting, bet in Japan they've built some good enclosures for these.

Having reverse engineered many Japanese alignments for local use [not worldwide] along with some others on various forums; overall, 'we' weren't impressed. Not surprising really when one considers typical local living space, construction, etc.. Pretty much what some of us refer to as 'girl and a guitar' type speaker.

GM
 
...But all this is irrelevant since the OP has some specific alignments in mind, so, smart guy, design him an Onken, BLH, Karlson or any other technically optimized cab he may show interest in using your way
Sealed boxes have no optimize* only maximize. The bigger the better. And better yet, is to make a largish box with lots of stuffing and leave the back off. I think the Stephens would like that.

I think an engineering analysis of such a box placed in a room a foot or two from the wall would challenge the capability of ordinary master's theses.

I'm not sure the beautiful high-tech trick tweeter would compare to a modern $30 silk dome. Dunno. Best to study how it (and tired old crossover components) perform.

Stephens has a glorious history originating - if I recall - with a Lansing break-away.

B.
*sim programs have Official Pronouncements of what's best for you in sealed boxes. My impression is the Official Pronouncement for sealed boxes will be a nonsense tiny box that is lousy in your room. Too bad it is forbidden to have insight into what criteria are being addressed by the sim or how that might relate to quality sound in your room. Don't the sim makers play their speakers in rooms?
 
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Ok guys seems like the best thing to do is get some results up here of the speakers. I'll put them in a simple baffle board and do some frequency sweep measurements.



I actually have some enclosure designed and made for some goodmans axiom 301 may just put them in there see how they respond.
 
Trusonic TS measurements

ok guys i got some results in, i used the dayton dats software and dats v2 device with the added mass option to get some TS measurements. This is just the woofer, i disconnected the concentric tweeter.

trusonic.jpg

* This data was exported from the Dayton Audio Test System: DATS
*
* Piston Diameter = 279.4 mm
* f(s)= 41.72 Hz
* R(e)= 7.069 Ohms
* Z(max)= 78.34 Ohms
* Q(ms)= 5.938
* Q(es)= 0.5889
* Q(ts)= 0.5357
* V(as)= 295.3 liters (10.43 cubic feet)
* L(e)= 1.118 mH
* n(0)= 3.473 %
* SPL= 97.51 1W/1m
* M(ms)= 26.02 grams
* C(ms)= 0.559 mm/N
* BL= 9.048
* K(r)= 0.2046
* X(r)= 0.4097
* K(i)= 0.02258
* X(i)= 0.616
*
*
Please see attached txt file for further results.
 

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Seems unlikely that the resonance is anywhere as high as 42 Hz (50% too high???) or the Bl as low as 9. Which would raise questions about the other measurements.

I like to do what might be called a sensitivity analysis where you bias the measurement in some way (say, adding some weight or using a precision weights to a weight measurement) and see if the new result is coherent.

I like to know lots about my tools, tend to be skeptical about the illusion of 3-decimal accuracy, and try to know when it matters or not.

B.
 
Ben i don't know how accurate the results are, all i know is that is what has been measured by the said device.

But agreed i should try different weights and see how the results change, i think the next thing to do is get my mic and use REW to do some frequency response measurements.

I have some horn cabinets which were made for the goodmans axiom 301's, i am just going to install them and listen.

I even have a pair of goodans ARU 172's which i was planning to use in the future, thinking may use the goodmans recommended enclosure size of 7800cu.ins see how it sounds.
 
ok guys i got some results in

Hmm, these fall in line with other brand's driver's specs back in the days of wanting to make replacement drivers in other brand's cabs, so curious when these were made, but if these specs are after considerable [re] breaking in to loosen them up and them still warm, then probably fine.

Do need to measure both though. Note that it advertised 30 Hz Fs, yet measures 40+ many decades later, implying it's frozen up some, but back in the day Altec drivers tended to be 10+ Hz above advertised, so inclined to accept yours if the other measures within +/- 10% if the above criteria is met on both.

GM
 
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