Proline X placeholder graphic reading Photos Coming Soon over a United States flag, product photography pending.

Performance Optimized · Datasheet

Performance Optimized Wedge Enclosure | Fits Kicker Solo X 8" Subwoofer Single 8" Sealed enclosure

Net volume
0.51 Cubic Feet
Max mounting depth
7-15/16 Inches, Cleared With Margin
Cutout
7-5/16 Inches (Kicker Spec)
External dimensions
13.5 Inches W × 11.75 Inches H × 10 Inches / 14.25 Inches D
Front baffle
Double-Layer 1.5" MDF Plus Trim Layer
Buy at Audio Intensity
  • Alignment: 0.51 cu ft net sealed wedge. Dual 1-ohm 49L7X81 lands at Qtc 0.707 (true Butterworth), Fc 54 Hz, F3 54 Hz; dual 2-ohm 49L7X82 runs Qtc 0.74, Fc 54 Hz, F3 52.2 Hz
  • Geometry: 20° front-firing wedge, vertical rear panel. 13.5 in W x 11.75 in H x 10 in top / 14.25 in bottom depth, the smallest footprint in the Solo X wedge line
  • Driver: Kicker Solo X L7X 8 (either coil version). Baffle CNC-cut to 7-5/16 in per Kicker spec, 7-15/16 in mounting depth cleared with margin
  • Wiring: One side-mounted terminal cup, 12 gauge OFC pre-wired. Kicker recommends 400-800 watts RMS; set final impedance at the driver's coils
  • Cabinet: 3/4 in Langboard Elite MDF, 1.5 in double-layer baffle plus trim, dado-locked brace behind the woofer, plush black carpet with black acrylic insert

Technical specifications

SeriesProline X Performance Optimized Wedge
Compatible DriverKicker Solo X L7X 8 (49L7X81 Dual 1-Ohm / 49L7X82 Dual 2-Ohm)
Enclosure TypeSealed | Single Driver | Front-Firing Wedge
Wedge Angle20 Degrees, Vertical Rear Panel
External Width13.5 Inches
External Height11.75 Inches
External Depth (Top)10 Inches
External Depth (Bottom)14.25 Inches
Internal Gross Volume0.61 Cubic Feet
Net Volume (After Driver Displacement)0.51 Cubic Feet
System Qtc (Dual 1-Ohm)0.707 Butterworth
System Qtc (Dual 2-Ohm)0.74
Predicted Fc54 Hz (D1) / 54 Hz (D2)
Predicted F3 (Anechoic)54 Hz (D1) / 52.2 Hz (D2)
Driver Fs (D1 / D2)48.0 Hz / 47.95 Hz (Kicker Factory)
Driver Qts (D1 / D2)0.630 / 0.651 (Kicker Factory)
Driver Vas (D1 / D2)3.75 L / 4.13 L (Kicker Factory)
Woofer Cutout7-5/16 Inches (Kicker Spec)
Mounting Depth Required7-15/16 Inches, Cleared With Margin
Recommended Power400-800 Watts RMS (Kicker Recommendation)
MaterialLangboard Elite 3/4" MDF
ConstructionShopSabre CNC | V-Groove and Dado Joinery
Panel Thickness3/4 Inch
Front BaffleDouble-Layer 1.5" MDF Plus Trim Layer
Internal Bracing3/4" Dado-Locked Brace Behind Woofer
Driver Mounting8/32 Threaded Inserts | Stainless Machine Screws Included
Terminal CupOne Proline X ABS/Carbon Fiber Composite | Side Mounted
Internal Wiring12 Gauge OFC, Pre-Wired
FinishPlush Black Carpet | Black Acrylic Insert
Bundle OptionsEnclosure Only (Bring Your Own Solo X 8)
Warranty1-Year Limited (Enclosure)
Built InTullahoma, Tennessee, USA

Performance in this enclosure

Net airspace
0.51
cu ft per chamber
System Qtc
0.71–0.74
sealed
Half power
52.2–53.8
Hz · F3
Xmax at
2371
W RMS · no filter
With 25 Hz subsonic
2804
W RMS · +18%
Amplifier
400–800
W RMS recommended
This enclosure holds 0.51 cu ft net per chamber. In it the Kicker SoloX L7X 8 (49L7X81) runs a system Qtc of 0.71–0.74 with half power at 52.2–53.8 Hz, and the cone reaches its 24.0 mm travel limit at 2371 W, above the driver’s 800 W thermal rating, so heat stops you before travel does. Run a subsonic filter at 25 Hz and that becomes 2804 W — +433 W, or 18 percent more power for the same 24.0 mm of travel.

01Is it a sealed driver?

Efficiency bandwidth product places the motor before anything else is decided.

EBP = Fs ÷ Qes = 62.3–65.3
SEALED 0–50 TRANSITION 50–100 PORTED 100–150 0 50 100 150 D1 65.3 D2 62.3
D1 · EBP 65.3D2 · EBP 62.3
At 62.3–65.3 the SoloX L7X 8 (49L7X81) sits in the transition band, not the sealed band. That is not a mismatch: a transition motor works in either alignment, and sealed buys a smaller box and a gentler roll-off at the cost of some low-end output. Stage 02 shows what this airspace actually does with it.

02What the box does to it

0.51 cu ft against a 3.8 L Vas.

α = Vas ÷ Vb = 0.26  ·  Fc = Fs√(α+1) = 54 Hz  ·  Qtc = 0.71–0.74
20 30 50 70 100 150 200 +6 +0 -6 -12 -18 -24 FREQUENCY · Hz LEVEL · dB −3 dB
D1 · Qtc 0.71, Fc 54 Hz, F3 53.8 HzD2 · Qtc 0.74, Fc 54 Hz, F3 52.2 Hz
The box lifts resonance from 48.0 Hz free-air to 54 Hz and half power lands at 52.2–53.8 Hz, anechoic, before any cabin gain. This enclosure ships without a driver, so both coil variants the maker offers are plotted. They do not load the same box the same way.

03The watts that reach Xmax (in this enclosure)

Travel scales with the square root of power, so there is one wattage that puts the cone exactly on 24.0 mm — and a bigger one once a subsonic filter stops it wasting travel below the passband.

PXmax = 2371–2450 W unfiltered  →  2804–3018 W with a 25 Hz subsonic
20 30 50 70 100 150 200 0 8 16 24 FREQUENCY · Hz CONE TRAVEL · mm PAST LINEAR TRAVEL · Xmax 24.0 mm 2371 W reaches Xmax here
D1 · 2450 W, no filterD2 · 2371 W, no filterD1 · 3018 W with subsonic at 25 Hz, 24 dB/octD2 · 2804 W with subsonic at 25 Hz, 24 dB/octXmax 24.0 mm one-way
Every trace touches the limit and no further, because each is drawn at the exact power that puts that coil on 24.0 mm. Unfiltered that is 2371 W, reached first at 20 Hz. It sits above the 800 W the driver can take thermally, so the voice coil gives up before the suspension does. The dashed traces are the same driver behind a subsonic filter at 25 Hz, 24 dB/oct: stopping the cone wasting travel below the passband lets it take 2804 W before hitting the same 24.0 mm. That is 18 percent more amplifier for the price of one filter setting.
ParamValueUnitNote
Fs48.00 / 47.95Hzfree-air resonance
Qts0.631 / 0.651D1 / D2
Vas3.75 / 4.13Lequivalent compliance
Sd249.6cm²effective piston area
Xmax24mmone-way linear travel
Pe800Wcontinuous RMS
SPL79.4dB1 W / 1 m, derived from T/S

Driver parameters as published by Kicker published Klippel T/S sheet. Curves computed against this enclosure’s actual net airspace.

Installer's take

The 8 is the sleeper of this line. Kicker put real SoloX motor architecture into the small frame, and in 0.51 net cubic feet the dual 1-ohm lands at Qtc 0.707 on the money, the same textbook Butterworth alignment as our 15. What you get is a genuinely fast, accurate sub that fits places nothing else in the Solo X family will.

Pick your coil version by your amplifier, not the box. The dual 2-ohm runs 0.74 here, close enough to Butterworth that no cab will tell the difference. Wire for the impedance your amp wants: dual 1-ohm for 0.5 or 2 ohm finals, dual 2-ohm for 1 or 4.

Be honest with yourself about the F3. Mid-50s anechoic sounds high on paper, but small-cab gain typically starts working below 60-70 Hz and works hardest exactly where this alignment rolls off, so in a pickup the 8 plays deeper than the chart suggests. It will not pressure-wash a crew cab like the 12, but for tight, tuneful low end at 800 watts it embarrasses a lot of lazy 10s.

The footprint is the selling point: 13.5 wide, 11.75 tall, 14.25 deep at the floor tapering to 10 at the top. That tucks behind a seat in trucks where even a shallow 10 box will not close the seat. Run 400-800 clean watts, set the gain properly, and let the sealed spring do the excursion control.

Questions

Will my Kicker Solo X 8 fit this enclosure?

Yes. The baffle is CNC-cut to Kicker's published 7-5/16 inch cutout for the Solo X L7X 8, and the cabinet clears the required 7-15/16 inch mounting depth with margin at every point of the stroke, including breathing room for the vented motor. Both the dual 1-ohm 49L7X81 and dual 2-ohm 49L7X82 fit identically.

What is a Butterworth alignment and why does it matter?

Butterworth describes a sealed system with a total Q of 0.707, the point where response stays maximally flat to the knee with no peak and no early sag. This cabinet's airspace was solved from Kicker's factory Thiele/Small parameters to land the dual 1-ohm Solo X 8 at 0.707 exactly, so you get the flattest, best-controlled bass the driver can produce in a sealed box, with the dual 2-ohm a whisker higher at 0.74.

Which coil version should I buy, dual 1-ohm or dual 2-ohm?

Choose by amplifier, not by the box. In this airspace the dual 1-ohm lands at Qtc 0.707 and the dual 2-ohm at 0.74; the audible difference in a vehicle is negligible. Buy the coil configuration that wires to the impedance your amplifier makes its rated power into: dual 1-ohm gives you a 0.5 or 2 ohm final, dual 2-ohm gives you 1 or 4 ohms.

How much power should I run to the Solo X 8 in this box?

Kicker recommends 400-800 watts RMS for the Solo X 8 and this sealed alignment supports the full range. The air spring keeps cone travel controlled as level rises, which is exactly what a high-excursion small driver needs. Clean power with properly set gains matters more than the number on the amp; an honest 500-600 watts covers most daily builds with headroom.

Can an 8 inch subwoofer really make enough bass for a truck?

In a truck cab, yes, and more than most people expect. The Solo X 8 is not a typical 8; it carries SoloX motor design and serious excursion for its size, and small cabins produce strong cabin gain in the exact region where this alignment rolls off. The result plays flatter and deeper in the vehicle than the anechoic chart suggests. It will not match the sheer displacement of our 12 or 15 wedges, but for tight, accurate bass in a space-limited cab it is a legitimately satisfying sub.

Will this wedge fit behind the seat of my truck?

This is the easiest fit in the entire Solo X wedge line. You need 13.5 inches of width, 11.75 inches of height, and 14.25 inches of depth at the floor; the top of the box needs only 10 inches because the baffle rakes back 20 degrees to follow the seat lean. The rear panel is fully vertical and sits flat against the cab wall. It fits behind the seat in most standard, extended, and crew cab trucks.

Is the subwoofer included with this enclosure?

No, this listing is the enclosure only. It is built specifically for the Kicker Solo X L7X 8 in either coil configuration, and you install your own driver using the pressed 8/32 threaded inserts and included stainless mounting hardware. If you want help pairing a Solo X 8 or an amplifier with it, call us at 931-563-5151.

Other Performance Optimized models