Kicker Q class 41L7152 15" Unboxing and detailed overview.

Unboxing and in depth tour of Kickers flagship Q class L7 15 inch square subwoofer.

From Kicker:
Why Square Subwoofers?
Most speakers you encounter are round. So why did Kicker make subwoofers that are square? The answer is very simple…more cone area. The advantage of having more cone area means you will get more air movement and that equals more bass output.
Round speakers have been the most common shape because they are relatively simple to construct. At low frequencies, the shape of the speaker cone does not affect the sound quality (as long as the cone is strong enough to resist flexing under pressure). Having more cone area will move more air than a smaller cone with less area. That is why large woofers are necessary if you want a lot of bass in your vehicle.
The only way to get more cone area for the same size of woofer is to make it square. A round speaker is essentially a square speaker with the corners rounded off. This will decrease the cone area and produce less bass output. If you leave more of the cone area intact, you will have more bass from that speaker. This is why Kicker has engineered square subwoofers. They required a lot of research and development but they deliver all the bass hardcore bass enthusiasts require.
Kicker did not invent the square speaker. Square speakers have been around for decades. Kicker did pioneer the deep dish, long travel, square subwoofer that is dedicated to producing maximum bass from a given area. This was made possible with the patented ribbed corners. The ribbed corners allow the surround to compress and expand as the cone travels in and out without deformation, distortion or unnecessary stress on the surround’s corners.
Using a 10” circle and a 10” square for an example…you will see roughly 27% more area in the 10” square. This means more cone area with the square subwoofer. area of a square = length x height - 10” x 10” = 100 square inches area of a circle = π (pi) x R (radius)² - 3.1416 x 5”² = 78.54 square inches. When calculating the cone area of a square speaker, the corners of the subwoofer are not perfectly square. There is some minimal rounding in the corners so there is a little less cone area that the formulas calculate. This is why we round down the area comparison to approximately 20% more cone area in a 10” square subwoofer
vs. a 10” round subwoofer.

Specifications:
Fs [Hz] 26.3
Sensitivity [1W, 1m] 88.6
Qts 0.539
Qms 11.868
Qes 0.565
Re [Ω] 7
Vas [ft³, L] 5.263, 149.048
Continuous Power Handling [Watts RMS] 1200
Outer Frame Dimension [in, cm] 15-5/8, 39.6
Mounting Depth [in, cm] 9 3/8, 23.9
Mounting Cutout [in, cm] 13-3/4, 34.9
Frequency Response [Hz] 18 - 100

T/S Parameters:
Re 3.575 Ohm electrical voice coil resistance at DC
Krm 0.05035 Ohm WRIGHT inductance model
Erm 0.655 WRIGHT inductance model
Kxm 0.08335 Ohm WRIGHT inductance model
Exm 0.665 WRIGHT inductance model
Cmes 1087.265 µF electrical capacitance representing moving mass
Lces 22.83 mH electrical inductance representing driver compliance
Res 58.25 Ohm resistance due to mechanical losses
fs 31.95 Hz driver resonance frequency

Mms 507.0675 g mechanical mass of driver diaphragm assembly including air load and voice coil
Mmd 469.6915 g mechanical mass of voice coil and diaphragm without air load
Rms 8.0135 kg/s mechanical resistance of total-driver losses
Cms 0.049 mm/N mechanical compliance of driver suspension
Kms 20.45 N/mm mechanical stiffness of driver suspension
Bl 21.5955 Tm force factor (Bl product)
Lambda 0.048 suspension creep factor

Qtp 1.048 total Q-factor considering all losses
Qms 12.7095 mechanical Q-factor of driver in free air considering Rms only
Qes 0.7815 electrical Q-factor of driver in free air considering Re only
Qts 0.736 total Q-factor considering Re and Rms only

Vas 73.53105 I equivalent air volume of suspension
n0 0.296 reference efficiency (2 pi-radiation using Re)
Lm 86.905 dB characteristic sound pressure level (SPL at 1m for 1W @ Re)
Lnom 87.4 dB nominal sensitivity (SPL at 1m for 1W @ Zn)

rmse Z 3.08 root-mean-square fitting error of driver impedance Z(f)
rmse Hx 3.44 root-mean-square fitting error of transfer function Hx (f)

Sd 1030.41 cm² diaphragm area
Xmax 21.5 mm