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Proline X PO 8TW-S W IDQS sealed wedge enclosure, product photos pending. Placeholder graphic reading Photos Coming Soon.

Performance Optimized · Datasheet

Performance Optimized Wedge Wide Sealed Triple 8" Enclosure Image Dynamics IDQS8 · Triple 8" Sealed enclosure

Net volume
1.378 cu ft per driver, 4.13 cu ft total, after both dividers and Image Dynamics's published 0.030 cu ft displacement per driver
Max mounting depth
3.11 in required; 14.07 in clearance above the motor against the raked rear panel
External dimensions
40 in W × 13 in at the seat face H × 23.00 in at the base D
Front baffle
1.5 in double baffle, outer layer machined as a flush recess
Buy at Audio IntensityFactory-direct, ships from Tullahoma
Image Dynamics IDQS8Buy at Audio Intensity
  • Best For: Triple Image Dynamics IDQS8 SUV Cargo-Floor Builds
  • Net Volume: 1.378 cu ft per Driver (4.13 cu ft Net Total)
  • Driver Match: Three Image Dynamics IDQS8 (Dual 2 Ohm), matched
  • Construction: 3 Chambers | 40" Wide Wedge | V-Groove/Dado | Double 1.5" Baffle | 3 Terminal Cups

Spec of record

Technical specifications

SpecificationValue
SeriesProline X Performance Optimized Wedge Wide
Compatible DriverImage Dynamics IDQS8, quantity 3, matched. Direct fit
ConfigurationTriple 8 inch sealed wedge, 3 chambers, 1 driver per chamber
Mounting PositionSUV cargo floor, raked face against the rear seat back
Firing DirectionRearward toward the liftgate. Not a down fire design
External Width40 in
External Height13 in at the seat face
External Depth23.00 in at the base, tapering to 18.27 in at the top
Internal Volume, Gross4.40 cu ft total
Internal Volume, Net Acoustic1.378 cu ft per driver, 4.13 cu ft total, after both dividers and Image Dynamics's published 0.030 cu ft displacement per driver
Driver Mounting Depth3.11 in required; 14.07 in clearance above the motor against the raked rear panel
Alignment Per DriverIDQS8 D2 Qtc 1.058, fc 57.2 Hz, F3 43.9 Hz anechoic
Woofer Openings3 at 7.299 in
Woofer LayoutOne row across the face
Frame Outer Diameter8.346 in
Fs / Qts / Qes / Qms53.0 Hz / 0.980 / 1.350 / 3.610
Vas / Sd / Xmax6.4 L / 214 cm2 / 7 mm
Driver Power Handling125 W RMS per driver, 375 W RMS for the set of 3 (thermal rating)
Recommended Amplifier70-100 W RMS per driver, 210-300 W RMS for the full set, at 3 ohms
Parameter SourceImage Dynamics published specifications
MaterialLangboard Elite MDF
ConstructionCNC cut, V-groove and dado joinery
Panel Thickness0.75 in
Front Baffle1.5 in double baffle, outer layer machined as a flush recess
Internal BracingTwo full-height 3/4 in dividers
Driver MountingThreaded inserts, stainless machine screws included
Terminal CupsThree Proline X ABS and carbon fiber composite, on the rear panel, one per chamber, pre wired 12 gauge OFC
Acrylic InsertGloss black acrylic baffle insert standard
DampingLight polyfill wall lining in every chamber, does not alter acoustic volume
CarpetPlush black
Shipping Weight85 lb
Warranty1 Year Limited
Built InTullahoma, Tennessee

Modelled response

Performance in this enclosure

Net airspace
1.378
cu ft per driver
System Qtc
1.06
sealed
Half power
43.9
Hz · F3
Xmax at
106
W RMS per driver · no filter
With 25 Hz subsonic
107
W RMS per driver · +1%
Amplifier, per driver
70–100
W RMS recommended
This enclosure holds 1.378 cu ft net per driver. In it the Image Dynamics IDQS8 D2 runs a system Qtc of 1.06 with half power at 43.9 Hz, and the cone reaches its 7.0 mm travel limit at 106 W per driver, below the driver’s 125 W thermal rating, so travel is what stops you here, not heat. A 25 Hz subsonic filter adds little here: 107 W per driver against 106 W, 1 percent. The box already resonates at 57 Hz, so its own rolloff has removed most of what the filter would have stopped.

00Sizing the amplifier

Every wattage on this panel is per driver. This cabinet holds three, so the amplifier feeds all three at once.

Per driver 70–100 W RMS  ×  3 drivers  =  full set 210–300 W RMS at 3 ohms
Look for a mono amplifier rated 210–300 W RMS at 3 ohms, the load the set wires to most easily. Travel sets the top here, not heat: past 107 W per driver the cone runs beyond Xmax even with the subsonic set, under the driver’s 125 W thermal rating. Below the bottom of the range it will play, just with less headroom; above the top you are buying power the drivers cannot use.

01Is it a sealed driver?

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

EBP = Fs ÷ Qes = 39.3
SEALED 0–50 TRANSITION 50–100 PORTED 100–150 0 50 100 150 Dual 2 Ohm 39.3
Dual 2 Ohm · EBP 39.3
EBP under 50 means a motor that wants a sealed load. The IDQS8 D2 sits at 39.3, inside that band, which is why this is a sealed build rather than a ported one.

02What the box does to it

1.378 cu ft against a 6.4 L Vas.

α = Vas ÷ Vb = 0.16  ·  Fc = Fs√(α+1) = 57 Hz  ·  Qtc = 1.06
20 30 50 70 100 150 200 +6 +0 -6 -12 -18 -24 FREQUENCY · Hz LEVEL · dB −3 dB
Dual 2 Ohm · Qtc 1.06, Fc 57 Hz, F3 43.9 Hz
The box lifts resonance from 53.0 Hz free-air to 57 Hz and half power lands at 43.9 Hz, anechoic, before any cabin gain. Figures are Image Dynamics’s published parameters; Qes and Qms reproduce the printed Qts. This cabinet holds three drivers in three separate sealed chambers of 1.378 cubic feet each, the volume plotted here.

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 7.0 mm, and in this alignment a subsonic filter barely moves it.

PXmax = 106 W per driver unfiltered  →  107 W per driver with a 25 Hz subsonic
20 30 50 70 100 150 200 0 4 8 FREQUENCY · Hz CONE TRAVEL · mm PAST LINEAR TRAVEL · Xmax 7.0 mm 106 W reaches Xmax here
Dual 2 Ohm · 106 W, no filterDual 2 Ohm · 107 W with subsonic at 25 Hz, 24 dB/octXmax 7.0 mm one-way
Every trace touches the limit and no further, because each is drawn at the exact power that puts that coil on 7.0 mm. Unfiltered that is 106 W per driver, reached first at 42 Hz. It sits under the 125 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, and they sit almost on top of the solid ones: 107 W per driver against 106 W. At 57 Hz the filter sits well below resonance, where the sealed alignment has already rolled the cone off at 12 dB/oct, so there is little wasted travel left for it to recover. Set it anyway to keep road rumble out of the cone, but do not size the amplifier around it.
ParamValueUnitNote
Fs53.00Hzfree-air resonance
Qts0.980Dual 2 Ohm
Vas6.42Lequivalent compliance
Sd214.0cm²effective piston area
Xmax7mmone-way linear travel
Pe125Wcontinuous RMS
SPL80.3dB1 W / 1 m, derived from T/S

Driver parameters as published by Image Dynamics IDQS8 D2 published specifications. Curves computed against this enclosure’s actual net airspace.

From the shop floor

Installer's take

Start with the size. 1.378 cubic feet per driver puts the IDQS8 at Qtc 1.058, resonance 57.2 Hz, half power 43.9 Hz anechoic. The wide platform stops at 23 inches deep, so this box lands a little above flat: a small lift near resonance and firm midbass.

Measure the base depth, not the top. This cabinet is 23.00 in deep where it meets the floor, 18.27 at the top, 40 wide and 13 tall. In an SUV the 40 has to clear between the rear wheel wells at floor height, the base depth is measured from the seat back with the seat upright and latched, and the 13 has to clear the cargo cover.

All three terminal cups are on the rear panel, and the rear panel is the face that goes against the seat back. Wire all three before the box goes in, with enough slack to slide it into place; once the raked face is against the seat you cannot reach them.

Impedance. IDQS8 D2: wire for 3 ohms (coils in parallel, the three in series), the load most monoblocks are built to deliver full power into; 1.33 ohms is the other clean option (coils in series, the three cups in parallel). Work the load out before you buy the amplifier, not after.

Power. Size the amplifier for the set, not one driver: 70 to 100 W RMS per driver is 210 to 300 W RMS across all 3 at 3 ohms. On this driver travel sets the top, not heat: Xmax arrives at 107 W per driver with a 25 Hz subsonic, under the 125 W rating.

Image Dynamics's Qes and Qms reproduce the printed Qts within 3 percent, so the alignment rests on a self-consistent set.

Polyfill is in as a wall lining in every chamber. Do not add more: it makes the box act larger and walks Qtc off 1.06.

Before you order

Questions

Does this fit the Image Dynamics IDQS8, and its coil versions?

Yes. Each opening is cut to 7.299 in for the 8.346 in frame, and the 3.11 in deep motor clears the raked rear panel with 14.07 in to spare. Coil versions of the Image Dynamics IDQS8 share the frame, cutout and mounting depth, so any of them drops in. The alignment on this page is computed on the IDQS8 D2 parameters.

Run three matched drivers, same model and same coil, so every chamber sees the alignment on this page.

Why 1.378 cubic feet per driver, and what alignment does it target?

On Image Dynamics's published Fs 53.0 Hz, Qts 0.980 and Vas 6.4 liters, 1.378 cubic feet per driver gives Qtc 1.058, system resonance 57.2 Hz and half power 43.9 Hz.

The wide platform stops at 23 inches deep, so this box lands a little above flat: a small lift near resonance and firm midbass.

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

Image Dynamics rates the IDQS8 at 125 watts RMS per driver. Recommended amplifier: 70 to 100 W RMS per driver, 210 to 300 W RMS for the full set of 3. Travel, not heat, sets the top: the cone reaches Xmax at 107 W per driver with a 25 Hz subsonic set, under the 125 W rating.

Each IDQS8 D2 has two 2 ohm voice coils, 4 ohms in series or 1 ohm in parallel. With each driver's coils in series and the three cups in parallel, the three present 1.33 ohms to a mono amplifier. With each driver's coils in parallel and the three in series, they present 3 ohms. Three drivers do not reach the round loads a pair does, so check the result against your amplifier's minimum stable impedance before powering up.

Will it fit my SUV?

It is 40 inches wide, 13 tall and 23.00 deep at the base, tapering to 18.27 at the top. Measure between the rear wheel wells, the floor depth with the seat upright, and the height under your cargo cover.

The raked face goes against the seat back and the woofers fire toward the liftgate.

Why are all three terminal cups on the back?

Each driver has its own sealed chamber, and the center chamber has no side wall to take a cup. Putting all three on the rear panel gives a matching set, one cup per chamber.

Wire them at the amplifier end; there is no cross-chamber wiring inside the cabinet.

What is the expected low-frequency extension?

Anechoic F3 is 43.9 Hz per driver with system resonance at 57.2 Hz.

Those figures exclude cabin gain. An SUV cabin adds real output below about 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 in every chamber, and the quantity is chosen so it does not change the acoustic volume.

Do not add more. Packing a sealed box makes it behave as though it were larger, which moves the alignment away from 1.378 cubic feet per driver.

Are the drivers included?

No. This is an enclosure only. You receive the cabinet finished in plush black carpet with the gloss black acrylic baffle insert, three pre-wired terminal cups on the rear panel, the polyfill lining in place, threaded inserts and stainless machine screws.

Bring three matched Image Dynamics IDQS8 drivers. The cabinet is cut direct fit to them, not a general purpose 8 inch box.

Same series, same size

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