JBL BassPro SL2 Under Seat Slim Subwoofer Review

[jbrown]

as long as we're contemplating the high end of car audio, I present the Cerwin Vega Stroker Pro Classic - 24 mm of Xmax (p-p I assume, but if that's one way it would exceed any other sub I could quickly find), and a $1400 price tag in the 15" size". I really like the idea of putting the second spider in front of the cone- I mean, it is a sub so who cares with the shape is? Would love to see someone design and build a good sub for this thing and then measure it:

Stroker Pro Classic 15″ Single Voice Coil SPL Subwoofer (2Ω) 1200W RMS - SPCL152

The Cerwin Vega STROKER PRO series subwoofers are designed for enthusiasts who demand high power, high performance, and exceptional sound quality from their car audio systems. Experience ultimate low-frequency power with the Cerwin Vega SPCL152 15" Stroker Pro Classic Subwoofer. 1200W RMS...

cerwinvega.com

The Cerwin Vega Strokers have been around since the late 90's. There is data for whatever you want somewhere.
BUT the JL Audio 13W7AE is 32mm one way and will play a lot louder and there are some others from Sundown that get even more insane.

 

[10PSPMemSticksForMiku2007]

I have stock Pioneer oldschool head unit door hooked to doormount 5" speakers with no subs in my work van. I actually had to kill ALL the bass boost, EQ down the bass significantly 80Hz as well as run a 4th order HPF at 50Hz with the built-in tools to get a semblance of neutral bass.

(BTW this combo sounds surprisingly good either on FM or when hooked to a Tunai Firefly LDAC->3.5mm portable receiver)

Its consistent with what I read about car interiors having massive inherent bass gain (~20dB at 20Hz) because the enclosed volume is so much smaller than residential rooms. I really don't see the point of car subs unless you want to annoy bystanders or get hearing damage.

I had a similar experience in my work van with a 40W Pioneer head unit and Polk's nicer 6.5" coaxial speakers, no sub. This is one of those vans with the cab completely sealed off from the back area; it was a solid metal wall directly behind the two seats. I never measured the frequency response, only correcting it by ear with the graphic EQ, but I'll swear it could make 30hz in there with aplomb. With that small cab, the heater and AC worked instantly, and the cabin gain was even more than a sedan's. Genuinely my favorite of all vehicles I've driven.

 

[Head_Unit]

No matter what I did with the three controls, I could not get anything that was not a mountain.

If anyone was wondering what "one note bass" looks like, I could hardly imagine a better example.

Don't confuse a mountain-shaped frequency response from this sealed (??) enclosure with the one-note bass from a bandpass enclosure with maybe a similar looking response. From long work in car audio I'd say what is happening here is the super small box shoves the resonance frequency way high, and the whole thing is operating in the rolloff region, like the "tiny" Bag End pro sub designed purposely to operate that way. Hence when you increase the lowpass frequency, you are kind of moving up the rolloff region.
- Now, how peaky is the response at resonance? Good question!
- What IS the resonance frequency? Another good question!
@amirm I'd be SO curious if you surgerized the thing open to measure the impedance curve of the driver/enclosure combination to find the resonance and calculate the Q

Saving grace here would seem to be that huge SPLs are not needed for a car, given that it's extremely near-field and a very small "room"

This is correct, it does not take much power at all to fill in the low end

Actually, it's the opposite -delivering strong bass in a car requires a significant amount of power.

But this is also correct if you want to play very loud at all-100 watts can get used up super easily because the sensitivity of the typical very small boxes relative to cone area is quite low. (The Thiele-Small sensitivity spec of the woofer is a MIDRANGE quantity, it has very very very little to do with actual sensitivity in the low bass, which seems most dominated by enclosure volume).

 

[Head_Unit]

Polk's nicer 6.5" coaxial speakers...I'll swear it could make 30hz in there with aplomb.

Oh quite possible. I've posted elsewhere my work buddy made some 5.25" prototypes for Alfa Romeo, and we were quite shocked their in-car measurement was flat to 20 Hz! You could not crank it up at all at such low frequencies but there was a LOT of cabin gain.