Speaker parameters

[RobXjcoupe]

I’m trying to find the following without much luck
Fs
Qes
Qms
Vas
Qts
Xmax
For an old kenwood kfc HQW250 subwoofer


Im hoping to build a specific frequency enclosure for it.
Any points in the right direction I thank you in advance

[RobXjcoupe]

No sooner as I posted the above I found what I was after

[TimmyMallett]

Wotcha doing? Making a box? Ported?

[RobXjcoupe]

I needed the info to build the above enclosure to the correct dimensions. The port will fire into the cabin of my car via the rear metal shelf (Centre hole) through a 100mm diameter port.

No visible subwoofer will be seen with the boot open. The frequencies generated will be boosted by +4db from 40hz to 110hz. I won’t have to over power in a sealed boot this time. The bass will be ported straight into the car.

I recently fitted a new surround to my Kenwood subwoofer, old school now but it’s a double magnet design using a cast aluminium basket. 200watts rms max power handling. I’m using a kenwood ps401m to power it. Gives me a bit of headroom and let’s the amp run cooler at half it’s max potential.

[TimmyMallett]

Proper old school kit! Looks like it will be in keeping with the car's era? Are you using something like Bass Box Pro with those TSPs?

[RobXjcoupe]

To be honest I found the equation somewhere last year and jotted it down for when needed. I just couldn’t find the parameters for the speaker once it was repaired to see what size enclosure was needed. The equation gives an s value also which Is needed for what dB boost is required and how much distortion would occur accordingly. More boost more distortion, less boost less distortion. The port is actually 300mm or 298.3mm to be precise. I’m hoping to box the rear and the door speakers. The doors will require more than a hole in card panel lol but I like a challenge. The car itself is older than the kit. But the kenwood is owned from new and I like it. I know how it works and sounds if that makes sense.

[David Beer]

I just couldn’t find the parameters for the speaker once it was repaired to see what size enclosure was needed. The equation gives an s value also which Is needed for what

Who repaired the speaker ? Not heard of that before !

[RobXjcoupe]

David Beer said:

I just couldn’t find the parameters for the speaker once it was repaired to see what size enclosure was needed. The equation gives an s value also which Is needed for what

Who repaired the speaker ? Not heard of that before !

The original foam surround had basically perished and turned to dust. I purchased a suitable new surround and repaired the speaker myself.
The s value is to do with dB ripple and helps calculate the port length and what frequency boost to expect accordingly.

[RobXjcoupe]

[broncoupe]

fabulous job