414-8a alnico 8 ohm T/S ?

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vega65

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Joined 2007
Sorry ....
Asuming alignment5,7 above.looking for a driver to fit in a smaller enclosure.ca 100l or less should be fine.
By the way GPA makes 414-8a alnico , specs promised pr Mail. The above indicates the 414 is candidate for future project.
 
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GM

GM

Member
Joined 2003
You're welcome!

Based on some others GPA 15" re-cones, it wouldn't surprise me if they only use the later 'B'/'Z' series which has a much lower Vas [~125-160 L of mine and others OEM units] to fit two in the 9844 studio monitors, so no problem fitting them in 100 L tuned to around/at Fs.

Anyway, please post GPA's specs.

GM
 
Inductor

Inductor

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Joined 2006

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nullspace

nullspace

Member
Joined 2004
According to GPA, the new production ferrite and AlNiCo 414s share the same T/S#s. Here's what they sent me:

RE 5.80 Ω (23◦ C)
FS 26.6 Hz
QTS 0.21
QMS 5.84
QES 0.21
SD 81.71 in.2 (0.053 m2)
XMAX 0.15 in. (4 mm)
VD 12.26 in.3 (0.2 l)
VAS 10.49 ft.3 (297.0 l)
ηo 2.52 %

I have a pair of the AlNiCo, but haven't yet had a chance to see how close mine match the published specs. I do have a box built, though...

Regards,
John
 
GM

GM

Member
Joined 2003
Inductor said:
THEY DON'T CARE WHEN THEIR MAIN INTEREST IS PROFIT. Some don't have labs anyway.:scratch1:
Click to expand...

While I've been fairly outspoken on this subject, including against GPA, they do have the test gear required and the well qualified staff to use it, but apparently is a 'shoestring' operation plus their primary market seems to me to be Asian where folks in general don't seem to care much about such details same as we all once felt..........

GM
 
Inductor

Inductor

Member
Joined 2006
GM said:
While I've been fairly outspoken on this subject...
Click to expand...
Just to say that (I) was not directing the critic to one manufacturer only (not Altec/GPA), look at PE that you can not find a pdf of output curves/documentation now. It's a problem of manufacturer/distributer/point of sale relation and no one wants to do the testing. Many diyAudio members also have that assertion that to much information available is BAD for the client. If you want something ASK! And this is when IT IS available. You loose your time and patience in the process. :)
 
nullspace

nullspace

Member
Joined 2004
Measuring the drivers was on my to-do list for the long holiday weekend, but since it's a timely topic I managed to get them done today. Here is the average for my pair:

Fs 32.385 Hz
Re 6.8 ohms[dc]
Le 308.76 uH
L2 999.405 uH
R2 19.09 ohms
Qt 0.315 -
Qes 0.325 -
Qms 7.82 -
Mms 30.765 grams
Rms 0.7996765 kg/s
Cms 0.000806 m/N
Vas 295.295 liters
Sd 510.71 cm^2
Bl 11.4663655 Tm
ETA 2.905 %
Lp(2.83V/1m) 97.44 dB

These were made with ARTA using the added-mass method. When measuring drivers on their back pointed up (so I can just lay four nickels on the cone), I find that both Fs and Qts tend to measure on the high side. And, these are fresh out-of-the-box -- no break-in. So, FWIW, YMMW, and all that... but GPA's published #s appear to be about right to me.

Regards,
John
 
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