Someone with LEAP please enter

[ocaukrell]

I have a pair of Nakamichi SP80 bass drivers (for car) that I'm trying to design a vented enclosure for and I would really appreciate any advise or help you can give.

The specs I have are;
8" driver
Fs 40
Qts .255
Qes .268
Qms 5.29
Vas 30.6 ltr
Xmax 7mm
4ohm
92db/w/m

So far the best I can come up (win isd) with is 22ltr, 42hz tuning and a port of 6x17cm
Would love to see what LEAP suggest as I believe you can add room gain or in this case Cabin gain being a small sedan.
size and power required are of no importance as I will use two in an isobarik setup with a 2x80wrms amp.
Not after Boom boom, after the best deep rumble I can get from them.
Many thanks....

Edit, found dimensions of car if it helps.

Passenger volume 2,670.3L
Boot volume 322.8L


TAAAA

 

[-CGL-]

Hi.

LEAP doesn´t suggest anything. It simulates given enclosure/driver/space. You have the standard parameter set, but LEAP works best with it´s .LTD model. To be able to help, I would need additional parameters such as Re, Sd, BL....

 

[ocaukrell]

Doh, Ok, best i can do is attach a scan of the 'owners sheet'

What are those values ? can I measure them myself ?

 

[-CGL-]

Re is the resistance of the voice coil. Sd is the effective area of the cone. BL you can´t measure easily...

 

[ocaukrell]

Ok,
sd = 40 cm Squared
Re = 4.4 ohms (thats measured resistance)
Bl = yeah right ok, have various bits if that helps (dmm, generator,cro if that helps)

 

[-CGL-]

I took the liberty to guess the rest of the parameters, like dia 180mm....

Compound box, 15l net. sealed.

Les see if I can attach the graph...

 

[ocaukrell]

Ta, 15 ltr sealed, now that s a surprise, everything i've tried it in says ported.
Freind has one in a 15 ltr ported tuned to about 47hz.
Whats the chance of bigger copy of that graph ? it's not quite readable sorry.
Yup diameter is exactly 180 (cone not surround)
Thanks for your help.