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Performance Optimized · Datasheet

Performance Optimized Down Fire Sealed 8" Enclosure Ampere Audio AA-2.0 8 · Single 8" Sealed enclosure

Net volume
0.88 cu ft after the brace and the driver displacement
Max mounting depth
5.14 in required, 0.75 in clearance above the motor
External dimensions
30.00 in W × 6.64 in in the down fire position H × 15.00 in D
Front baffle
1.5 in double baffle, outer layer machined as a flush recess
Buy at Audio IntensityFactory-direct, ships from Tullahoma
Ampere Audio AA-2.0 8Buy at Audio Intensity
  • Alignment: 0.88 cu ft net, Qtc 0.68, F3 49.6 Hz; height set by the motor, not the airspace
  • Driver: Ampere Audio AA-2.0 8 (dual 4 ohm), 500 W RMS, 14 mm Xmax, 5.14 in mounting depth
  • Standoffs: Included, 1.75 in, shipped uninstalled. Installed height near 8.39 in
  • Cabinet: 30.00"W x 15.00"D x 6.64"H in down fire position, excludes standoffs, square corners

Spec of record

Technical specifications

SpecificationValue
SeriesProline X Performance Optimized Down Fire
Compatible DriverAmpere Audio AA-2.0 8 (dual 4 ohm), quantity 1. Direct fit
ConfigurationSingle 8 inch, sealed down fire
Mounting PositionTrunk or cargo floor, baffle facing down on standoffs
Firing DirectionDownward. Feet ship uninstalled, so front or up firing is also possible
External Width30.00 in
External Depth15.00 in
External Height6.64 in in the down fire position, excludes standoffs
Installed Height8.39 in including the 1.75 in standoff
Internal Volume, Gross0.94 cu ft
Internal Volume, Net Acoustic0.88 cu ft after the brace and the driver displacement
Height Set ByDriver clearance: the 5.14 in motor, not the airspace
Driver Mounting Depth5.14 in required, 0.75 in clearance above the motor
Floor Slot1.28 times the cone area at the 1.75 in standoff
Alignment, dual 4 ohmQtc 0.678, fc 47.5 Hz, F3 49.6 Hz anechoic
Woofer Opening7.20 in, Ampere's published cutout
Frame Outer Diameter8.50 in
Bolt CircleNot printed by Ampere; threaded insert kit included
Driver Displacement0.052 cu ft, estimated; Ampere publishes none
dual 4 ohm Fs / Qts / Qes / Qms / Vas42 Hz / 0.6 / 0.72 / 4.86 / 6.91 L
Driver Sd200 cm2, derived from Ampere's Vas, Fs and moving mass
Xmax14 mm one way, Ampere spec
Driver Power Handling500 W RMS
Wiring OptionsThis cabinet is for the AA-2.0 8 dual 4 ohm: the dual 4 ohm is two 4 ohm coils, 8 ohms in series or 2 ohms in parallel. A parallel load at or under 1 ohm needs an amplifier rated for it.
Parameter SourceAmpere Audio published T/S and dimension tables, AA-2.0 series page
MaterialLangboard Elite MDF
ConstructionCNC cut, V-groove and dado joinery, square corners
Panel Thickness0.75 in
Front Baffle1.5 in double baffle, outer layer machined as a flush recess
Internal BracingWindowed brace, dadoed to the shell
Driver MountingThreaded insert kit included, NOT pre-installed: Ampere prints no bolt circle
Terminal CupsOne Proline X ABS and carbon fiber composite, side mounted, pre wired 12 gauge OFC
StandoffsIncluded, 1.75 in, shipped uninstalled
DampingLight polyfill wall lining, does not alter acoustic volume
CarpetPlush black
Shipping Weight40 lb
Warranty1 Year Limited
Built InTullahoma, Tennessee

Modelled response

Performance in this enclosure

Net airspace
0.88
cu ft
System Qtc
0.68
sealed
Half power
49.6
Hz · F3
Xmax at
267
W RMS · no filter
With 25 Hz subsonic
367
W RMS · +38%
Amplifier
500
W RMS recommended
This enclosure holds 0.88 cu ft net . In it the Ampere Audio AA-2.0 8 runs a system Qtc of 0.68 with half power at 49.6 Hz, and the cone reaches its 14.0 mm travel limit at 267 W, below the driver’s 500 W thermal rating, so travel is what stops you here, not heat. Run a subsonic filter at 25 Hz and that becomes 367 W — +100 W, or 38 percent more power for the same 14.0 mm of travel.

01Is it a sealed driver?

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

EBP = Fs ÷ Qes = 58.3
SEALED 0–50 TRANSITION 50–100 PORTED 100–150 0 50 100 150 D4 58.3
D4 · EBP 58.3
At 58.3 the AA-2.0 8 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

0.88 cu ft against a 6.9 L Vas.

α = Vas ÷ Vb = 0.28  ·  Fc = Fs√(α+1) = 47 Hz  ·  Qtc = 0.68
20 30 50 70 100 150 200 +6 +0 -6 -12 -18 -24 FREQUENCY · Hz LEVEL · dB −3 dB
D4 · Qtc 0.68, Fc 47 Hz, F3 49.6 Hz
The box lifts resonance from 42.0 Hz free-air to 47 Hz and half power lands at 49.6 Hz, anechoic, before any cabin gain. Ampere prints no cone area for this driver; it is derived from Ampere’s own Vas, Fs and moving mass. Driver displacement is not published and is estimated. Only the D4 coil is plotted: the other version falls outside a well-behaved sealed alignment in this cabinet.

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 14.0 mm — and a bigger one once a subsonic filter stops it wasting travel below the passband.

PXmax = 267 W unfiltered  →  367 W with a 25 Hz subsonic
20 30 50 70 100 150 200 0 4 8 12 16 FREQUENCY · Hz CONE TRAVEL · mm PAST LINEAR TRAVEL · Xmax 14.0 mm 267 W reaches Xmax here
D4 · 267 W, no filterD4 · 367 W with subsonic at 25 Hz, 24 dB/octXmax 14.0 mm one-way
Every trace touches the limit and no further, because each is drawn at the exact power that puts that coil on 14.0 mm. Unfiltered that is 267 W, reached first at 20 Hz. It sits under the 500 W the driver can take thermally, so the enclosure sets the ceiling, not the voice coil. 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 367 W before hitting the same 14.0 mm. That is 38 percent more amplifier for the price of one filter setting.
ParamValueUnitNote
Fs42.00Hzfree-air resonance
Qts0.600D4
Vas6.91Lequivalent compliance
Sd200.0cm²effective piston area
Xmax14mmone-way, as Ampere publish it
Pe500Wcontinuous RMS
SPL80.4dB1 W / 1 m, derived from T/S

Driver parameters as published by Ampere Audio published T/S table. Curves computed against this enclosure’s actual net airspace.

From the shop floor

Installer's take

0.88 cubic feet: Qtc 0.678 on the dual 4 ohm, F3 49.6 Hz.

Only the dual 4 ohm coil is listed. In this airspace the dual 2 ohm goes too dry to recommend sealed; it belongs in a ported box.

Measure the installed height, not the cabinet height: 6.64 tall on its own, 8.39 with the standoffs on the 30 by 15 footprint.

Ampere's table needed reading carefully: no cone area is printed, so it is derived from their own Vas, Fs and moving mass. Displacement is estimated.

Inserts ship in the kit, not pressed: Ampere prints no bolt circle. Mark from the driver, drill, press. Sealed, so leave the polyfill as it is and run it at 500 watts or under per driver.

Before you order

Questions

Does this fit the Ampere Audio AA-2.0 8, and will any other 8 inch fit?

The AA-2.0 8, yes, in the dual 4 ohm version. The baffle is cut to 7.20 in, Ampere's published cutout, under the 8.50 in frame. The 5.14 inch motor clears the cabinet with 0.75 inch to spare. This cabinet is listed for the AA-2.0 8 dual 4 ohm only. Ampere's dual 2 ohm version reads Qtc 0.57 in the same airspace, too damped to sound right sealed, so it is not offered in this enclosure.

Any other 8, no. The airspace is engineered around the AA-2.0 8's own Qts and Vas, and a different woofer that happened to drop into the hole would not see the alignment printed on this page.

Why 0.88 cubic feet, and what alignment does it target?

0.88 cubic feet net on Ampere's published figures: the dual 4 ohm reads Qtc 0.678 with resonance at 47.5 Hz and half power at 49.6 Hz. That is a slightly over-damped alignment: a gentle, early rolloff and tight transients rather than a flat top.

The 5.14 inch mounting depth sets the minimum cabinet height here, so the airspace is what the motor allows rather than a free choice.

What amplifier power should I run, and how should I wire it?

Ampere rates the AA-2.0 8 at 500 watts RMS, so target 350 to 500 watts RMS at the final load.

This cabinet is for the AA-2.0 8 dual 4 ohm: the dual 4 ohm is two 4 ohm coils, 8 ohms in series or 2 ohms in parallel. A parallel load at or under 1 ohm needs an amplifier rated for it. Confirm your amplifier's minimum stable impedance first.

How tall is this once the standoffs are on?

The cabinet is 6.64 inches tall measured in the down fire position, and that figure excludes the standoffs. The standoffs hold 1.75 inches under the baffle, so plan your space around a finished stack of roughly 8.39 inches.

The footprint is the standard Performance Optimized down fire platform, 30.00 inches wide by 15.00 deep. Height is the only dimension solved to the driver, and here it is the AA-2.0 8's 5.14 inch motor that sets it.

Why is the front baffle double-layered?

The baffle is two bonded 3/4 inch sheets, 1.5 inches through. A single 3/4 inch panel flexes under the pressure an 8 inch woofer puts on it at 500 watts, which smears output and works the driver loose over time; the second layer stiffens the face and gives the mounting hardware twice the material to bite.

The outer layer is machined as a flush recess to Ampere's 8.50 inch frame, so the driver bolts to the inner layer.

What is the expected low-frequency extension?

Anechoic F3 is 49.6 Hz. Below Qtc 0.707 the rolloff is gentle and F3 sits above fc, which is what an over-damped sealed box does.

Those figures exclude cabin gain. In a car the cabin's transfer function adds real output below 50 Hz, so in-vehicle response runs deeper than the numbers above.

Do I need to add polyfill or damping?

No. Polyfill is already installed as a light wall lining to control internal reflections, and the quantity is chosen so it does not change the acoustic volume.

Do not add more. Packing a sealed box with fill makes it behave as though it were larger, which walks the alignment away from the 0.88 cubic feet this cabinet was built to.

Is the driver included, and are the threaded inserts installed?

No driver. This is an enclosure only. You receive the cabinet finished in plush black carpet, one side-mounted pre-wired terminal cup, the polyfill lining already in place, the standoffs, and a threaded insert kit with stainless machine screws.

The inserts ship loose on purpose: Ampere prints no bolt circle for the AA-2.0 8, so you set the driver in the recess, mark its holes, drill and press the inserts. The Ampere Audio AA-2.0 8 is purchased separately, and the cabinet is cut direct fit to it, not a general purpose 8 inch box.

Same series, same size

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