Fostex 12w150

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#2
To answer my question;
Found the answer through a dutch PA-shop forum (new-line.nl);

The old patents for (at least some) Fostex drivers have been bought by US Magnetics (Bell).
The Bell site neatly mentions that its 12L300 is replacement for the Fostex 12W150.

I mailed their German division for TS parameters, I received them a few hours later.. Now that's good service. 🙂


TS parameters from the scan they sent;
12W150.jpg
 
#4
ScottG said:
1.2mm of xmax..

Look elsewhere, like:
...
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Why, if you don't know voltcontrol' project. Probably you don't know what Xmas is...NPI.🙂
On another note, the Fostex 12w150 might be a good driver, for a mid, within a +/-100dBs system. Very much in line with other guitar type speaker drivers like the Celestion G 12-P, Fane, Eminence, others.
Sure, the Eminence Kappalite 3012HO Neo 12" has a lower Fs, but has only 70dB@300Hz comparing with close to 100dB@300Hz of the other drivers, and that's about 30dB difference.😡
 
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#5
Inductor said:
(About)... the Eminence Kappalite 3012HO Neo 12"...
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Sorry, I looked to the wrong (left) side, when I should be looking to the 98dB on the right side, my wrong (to late for a post update). What I was saying anyway was that, for a woofer, because of the lower Fs, probably should be better depending on applications. As for a mid output, they should be even, looking to specs on paper, not to mention the output profile of the Eminence asking for a horn like speaker🙂
ScottG said:
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Augerpro has used it for this design with the Qsc waveguide.

HTGuide Forum - Can you smell what Brando's cooking!?
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And good link, because augerpro speaker looks amazing.
 
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#6
@ScottG;I know what Xmax is and what that means in regards to bass response of this unit (, the last 12" I owned had plenty of it; Ciare SW1200).
Keep in mind that Xmax doesn't necessarily always mean the same, look at the performance of low bass drivers in a (tapped) horn for instance.
The other end being OB perhaps.

So why a big cone driver with low excursion, good SPL reaction and seamably a good frequency response in to the midrange?
I have my eyes fixed on the econowave project over at audiokarma and on Geddes' WG theory for a while now.
I also really like Danley products and William Cowons home system.
However; I cannot get the idea out of my brain that a cone midrange will sound superior, at least in the lower midrange.
So the fostex or any other 6" to 12" contender (big scope eh..) will be performing (at least lower) midrange duties and my project will be 3 way.

Regards, Pim

Ps the only choice that's set is BMS 4524 on highs, if i'd have the budget the Eighteensound 6ND430 would be my midrange choice. Bass will probably be 2 x 15", haven't made a shortlist on those yet.
 
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#7
I don't want to be mean for anyone (voltcontrol, ScottG), just saying that Xmax/Xlim mean different things for different manufacturers and vendors and diy designers. I don't know what it is by now or what it should be (either a T/S parameter or not, mathematical Xmax or percentage of Xlim, tested or calculated). It's a good theme for a new forum post.😎
 
#8
voltcontrol said:
Keep in mind that Xmax doesn't necessarily always mean the same, look at the performance of low bass drivers in a (tapped) horn for instance.
The other end being OB perhaps.

So why a big cone driver with low excursion, good SPL reaction and seamably a good frequency response in to the midrange?

However; I cannot get the idea out of my brain that a cone midrange will sound superior, at least in the lower midrange.

So the fostex or any other 6" to 12" contender (big scope eh..) will be performing (at least lower) midrange duties and my project will be 3 way.

Regards, Pim
Click to expand...

Inductor said:
I don't want to be mean for anyone (voltcontrol, ScottG), just saying that Xmax/Xlim mean different things for different manufacturers and vendors and diy designers. I don't know what it is by now or what it should be (either a T/S parameter or not, mathematical Xmax or percentage of Xlim, tested or calculated). It's a good theme for a new forum post.😎
Click to expand...


No offense taken. 🙂

This link has a good explanation of xmax:

Speaker



Voltcontrol - if you want to achieve a more directive response with potentially better off-axis power matching between a compression driver + waveguide and a smaller diameter midrange then you can either:

1. Experiment with a cardioid design - loading the driver aperiodically a'la Amphion, or
2. Using a waveguide for the midrange as well.

(note that QSC also has a midrange waveguide as well as the nice compression driver waveguide that Augerpro used - but it only extends down to about 500 Hz.)

Another *possibility* to achieve better off-axis power matching is "simply" going with a "shallow" low-order crossover between the 2 drivers. Note however that this method will not likely result in the same sort of uniform pressure loss off-axis (as it achieves at higher freq.s due to the compression driver's waveguide).

As for a smaller driver being a better midrange or not.. that largely depends on your priority for the design. Certainly smaller diameter drivers will be more likely to extend higher in freq. before the driver's break-up resonance occurs.

Here is augerpro's testing of the several drivers including the 12" eminence I posted:

Driver Measurements (drivervault)

If you are looking for a low mass eff. mid at a low price that would do well with a cardioid design then perhaps the Omnes Audio L8 (..not the "spec." version). It certainly won't be a low non-linear distortion driver even within xmax, but you might not care. (..and you will of course need to limit the drivers low freq. extension.)
 
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