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Old 18th February 2015, 02:26 PM   #1
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Default subwoofer enclosure what size thiele/small included

Hi i have an Eminence driver 12" LTD-MK2 subwoofer from my in car thump thump days,

can not find a great deal of information on the internet I purchased it around 2001 it has not been used for years so i am trying to find out what size enclosure i need to build.

do not realy want to throw it away

It is to help out on my lampizator/endorphin p17 open baffle build eminence alpha 15A with saba greencones, the two alphas arrived this morning so got some work to do building baffle etc.And a bit of home theatre crash bang wallop

here is the parameters taken from this website

https://www.google.co.uk/url?sa=t&rc...o77dFG9rpEMZMQ

https://www.google.co.uk/url?sa=t&rc..._YxisPS9UhZrzQ


THIELE SMALL settings and speaker level on IRC EMINENCE LTD-12MK2:

Definition Parameter Values Formulas. MKSA units
Resonance Frequency F s 37.85 Hz Value of the database
Air volume equivalent to the elasticity of the suspension V AS 123.18 L Value of the database
Coil resistance at DC R e 2.65 Ohms Value of the database
Internal resistance of the amplifier R g 0.00 Ohms Damping factor of 8 Ohms 200000
Crossover resistance R f 0.00 Ohms If 0: No active filter or
Coefficient mechanical overvoltage Q ms 10.040 Value of the database
Coefficient of electrical overvoltage Q es 0.510 Value of the database
Coefficient of total overvoltage Q ts 0485 Q * Q es ms / (Q + Q es ms)
Type calculated F s / Q ts 78.0 Hz F s / Q ts
Type GRAVE IN TEST
Surface of the membrane S d 532.36 cm 2 Value of the database
Radius of the membrane R d 13.02 cm root (S d / ft)
Equivalent standard diameter D iameq 31 cm Rules for calculating the diameter
Compliance acoustic suspension C ase 8735.2 Ncm 5 V AS / (R * o C 2)
Total mass of acoustic diafragme M as 20.2 kgm 4 1 / ((2 * Pi * F s) 2 C as)
Mechanical moving mass M ms 57365 g (C * S d / (2 * Pi * F s)) 2 * R o / V AS = M * S as d 2
Mechanical mass frontal radiation M mrf 7.022 g (8 * R * R o d 3) / 3
Mass of the membrane M md 50343 g M -M ms mrf
Strength R ms 1359 Kg / s 2 * Pi * F * M s ms / ms Q
Compliance of the suspension C ms 0.308 mm / N 1 / (2 * Pi * F s) 2 / M ms
Stiffness of the suspension K 3244 N / m 1 / C ms
Force factor BL 8419 N / A (2 * Pi * F * M ms * s R e / Q es) 1/2
BL / M ms BL / M ms 146.8 kg.m / s 2 / A This is not a selection criterion
Linear stretch of the membrane X max 5.60 mm Value of the database
X max PP pp 11.20 mm 2 * X max
Air volume displaced by the membrane V d 298.12 cm 3 S d * X max
Displacement of the point of the rest
upright membrane X Green 0.06 mm * M * C 9.81 ms
Yield% Makes 1.273% (4 * Pi 2 / C 3) * (F s 3 * AS V / Q es) * 100
Constant sensitivity Cste direction 112.13 dB 10 * LOG (R o * C / 2 / Pi) -20 * LOG (2 * 10 -5)
Sensitivity in 2 * Pi steradian
Valid in the medium to below 420 Hz
for operation in piston SPL 98.0 dB / 2.83V / m 10 * LOG (Makes / 100) +112.13
+ 10 * LOG (8 / (R + R e g + R f))
93.2 dB / W / m 10 * LOG (Makes / 100) +112.13
Sensitivity in 4 * Pi steradian (with reservation)
Valid in the low, below a frequency
which depends on the size of the front panel. SPL 94dB / 2.83V / m 10 * LOG (Makes / 100) +112.13
+ 10 * LOG (8 / (R + R e g + R f)) - 4
89.2 dB / W / m 10 * LOG (Makes / 100) + 112.13-4
Power cut-off frequency F e 541 Hz 1 / (2 * pi * (T / (R + R e f g + R)))
All values ​​in the table are calculated from the values ​​stored in the database, F s, AS V, R e, Q ms, Q es, S d, T and X max.



Parameters for the simulation in an electric software EMINENCE LTD-12MK2
Definition Parameter Values Formulas
MKSA units
Equivalent resistance R es 52.17 Ohms B 2 L 2 / R ms
Equivalent inductance T he 21.85 mH B * C 2 L 2 ms
Equivalent capacity T hese 809.24 uF M ms / B 2 L 2
All values ​​in the table are calculated from the values ​​stored in the database, F s, AS V, R e, Q ms, Q es, S d, T and X max.

thanks guys
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Old 18th February 2015, 02:46 PM   #2
Did it Himself
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Those old Eminence subs (did you buy it from Maplin?) were really just cosmetically modified PA drivers. As such, they are not really suitable for home subwoofer use. Resonance frequency is too high and they need a big box.

How they got away with marketing them as car subs... well the market back then was a lot less clued up and developed.
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Old 18th February 2015, 02:58 PM   #3
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i bought just one from a car audio shop in lincoln

now i know eminence did a range of speakers with blue and green foam surrounds with numbers printed across the the dust cap its not one of them

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.

here is the email response from eminence when i enquired

Here are the T/S parameters for LTD-12MK2:

05-RE OHMS 2.65 13-FS HZ 37.85
06-LE MH .78 14-MMS GMS 57.10
07-QM 10.04 15-CMS mm/N .3095
08-QE .510 16-RMS NS/M 1.3536
09-QT .480 17-VAS LTRS 123.18
10-XMAX MM 5.60 18-SD SCM 532.36
11-BL TM 8.44 19-EBP 74.9
12-EFF % 1.27 20-SPL dB 93.1


Best Regards,


ANTHONY LUCAS
Design Engineer/Technical Support

Last edited by charlie2; 18th February 2015 at 03:24 PM.
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Old 18th February 2015, 03:29 PM   #4
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13-FS HZ 37.85
14-MMS GMS 57.10
15-CMS mm/N .3095
16-RMS NS/M 1.3536
17-VAS LTRS 123.18
18-SD SCM 532.36
19-EBP 74.9
20-SPL dB 93.1
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Old 18th February 2015, 04:19 PM   #5
bjorno is offline bjorno  Sweden
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Quote:
Originally Posted by charlie2 View Post
13-FS HZ 37.85
14-MMS GMS 57.10
15-CMS mm/N .3095
16-RMS NS/M 1.3536
17-VAS LTRS 123.18
18-SD SCM 532.36
19-EBP 74.9
20-SPL dB 93.1
Hi Charlie,

Here is a suggestion:

b
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Old 18th February 2015, 06:09 PM   #6
GM is offline GM  United States
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Quote:
Originally Posted by charlie2 View Post
If you scroll down far enough you'll see that this link is nearly a 'one stop shop' website with a bunch of different BR and sealed alignments along with clickable links to design your own sealed, BR, BP, TL alignments, though for strictly 'sub' duty, bjorno's T-TQWT that's not available there is probably the best choice overall.

GM
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Old 20th February 2015, 02:52 PM   #7
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hi bjorno

thank you very much for taking time on this, look forward to a box design

and thanks to others for positive replies
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