Proline X PO 10-S DF IKS10 sealed down fire enclosure, front panel on 1.75 inch feet, 29.5 by 4.8 inches.

Proline X PO 10-S DF IKS10 sealed down fire enclosure, end panel with recessed terminal cup, 15 by 4.8 inches.

Performance Optimized · Datasheet

Helix IK S10 Box: Sealed 10" Shallow Down Fire Enclosure Single 10" Sealed enclosure

Net volume: 0.49 cu ft
Max mounting depth: 3.33 in required by the driver
Cutout: 9.0100 in
External dimensions: 29.45 in W × 4.83 in measured in the down fire position H × 15 in D
Front baffle: 1.5 in, double baffle

Buy at Audio IntensityFactory-direct, ships from Tullahoma

Helix IK S10Buy at Audio Intensity

Best For: Helix IK S10 Floor-Firing Builds
Net Volume: 0.49 cu ft (0.54 cu ft Gross)
Alignment: Qtc 0.833 to 0.862, fc 62.5 to 63.0 Hz, F3 53.3 to 54.8 Hz anechoic
Driver Match: Helix IK S10, SVC2 or DVC2
Impedance: 2 ohm SVC2; 1 or 4 ohm DVC2
Construction: Down-Firing Sealed | V-Groove/Dado | Double 1.5" Baffle | Threaded Inserts | Feet Included

Spec of record

Technical specifications

Specification	Value
Series	Proline X Performance Optimized Down Fire
Compatible Driver	Helix IK S10 SVC2 or DVC2, quantity 1. Direct fit
Configuration	Single 10 inch, single chamber sealed down fire
Mounting Position	Trunk or cargo floor, cone firing downward
Firing Direction	Downward into the floor. Feet included, uninstalled
External Width	29.45 in
External Height	4.83 in measured in the down fire position
External Depth	15 in
Internal Volume, Gross	0.54 cu ft
Internal Volume, Net Acoustic	0.49 cu ft
Alignment	Qtc 0.833 to 0.862, fc 62.5 to 63.0 Hz, F3 53.3 to 54.8 Hz anechoic
Helix Recommended Volume	14 litres net, which is what this is built to
Driver Cutout	9.0100 in
Driver Mounting Depth	3.33 in required by the driver
Power Handling	300 watts RMS
Floor Slot Ratio	0.91 at the standard 1.75 in standoff
Feet	Included, uninstalled
Impedance	SVC2 is a single 2 ohm coil; DVC2 is dual 2 ohm, 1 ohm parallel or 4 ohm series
Xmax	8 mm one way, both coil versions
Material	Langboard Elite MDF
Construction	CNC cut, V-groove and dado joinery
Panel Thickness	0.75 in
Front Baffle	1.5 in, double baffle
Internal Bracing	Internal brace
Driver Mounting	Threaded inserts at every mounting location, stainless machine screws included
Terminal Cups	One Proline X ABS and carbon fiber composite, side mounted, pre wired 12 gauge OFC
Damping	Light polyfill wall lining, does not alter acoustic volume
Carpet	Plush black
Weight	29.7 lb
Warranty	1 Year Limited
Built In	Tullahoma, Tennessee

Modelled response

Performance in this enclosure

Net airspace

0.49

cu ft per chamber

System Qtc

0.83–0.86

sealed

Half power

53.3–54.8

Hz · F3

Xmax at

107

W RMS · no filter

With 25 Hz subsonic

111

W RMS · +4%

Amplifier

300

W RMS recommended

This enclosure holds 0.49 cu ft net per chamber. In it the Helix IK S10 runs a system Qtc of 0.83–0.86 with half power at 53.3–54.8 Hz, and the cone reaches its 6.0 mm travel limit at 107 W, below the driver’s 300 W thermal rating, so travel is what stops you here, not heat. A 25 Hz subsonic filter adds little here: 111 W against 107 W, 4 percent. The box already resonates at 63 Hz, so its own rolloff has removed most of what the filter would have stopped.

01Is it a sealed driver?

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

EBP = Fs ÷ Qes = 68.5–69.4

SVC2 · EBP 68.5DVC2 · EBP 69.4

At 68.5–69.4 the IK S10 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

0.49 cu ft against a 26.0 L Vas.

α = Vas ÷ Vb = 1.86 · Fc = Fs√(α+1) = 63 Hz · Qtc = 0.83–0.86

SVC2 · Qtc 0.86, Fc 63 Hz, F3 53.3 HzDVC2 · Qtc 0.83, Fc 63 Hz, F3 54.8 Hz

The box lifts resonance from 34.0–37.0 Hz free-air to 63 Hz and half power lands at 53.3–54.8 Hz, anechoic, before any cabin gain. The wedge and the down-fire, single and dual, all hold this same volume per chamber, so these numbers describe every version of this enclosure. Power figures are per driver, for one driver in its own chamber. Helix measures the SVC2 and the DVC2 separately rather than publishing one set for both, so both are carried here rather than averaged. Note that the F3 above is anechoic and reads higher than the figure on Helix's datasheet, which is quoted with their recommended DSP highpass applied.

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

P_Xmax = 107–113 W unfiltered → 111–116 W with a 25 Hz subsonic

SVC2 · 113 W, no filterDVC2 · 107 W, no filterSVC2 · 116 W with subsonic at 25 Hz, 24 dB/octDVC2 · 111 W with subsonic at 25 Hz, 24 dB/octXmax 6.0 mm one-way

Every trace touches the limit and no further, because each is drawn at the exact power that puts that coil on 6.0 mm. Unfiltered that is 107 W, reached first at 33 Hz. It sits under the 300 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: 111 W against 107 W. At 63 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.

Param	Value	Unit	Note
Fs	37.00 / 34.00	Hz	free-air resonance
Qts	0.510 / 0.450		SVC2 / DVC2
Vas	26.00 / 34.00	L	equivalent compliance
Sd	353.0	cm²	effective piston area
Xmax	6	mm	one-way linear travel
Pe	300	W	continuous RMS
SPL	85.7	dB	1 W / 1 m, derived from T/S

Driver parameters as published by audiotec-fischer.de and the HELIX datasheet. Curves computed against this enclosure’s actual net airspace.

From the shop floor

Installer's take

0.49 cubic feet net at Qtc 0.833 to 0.862 and F3 53.3 to 54.8 Hz anechoic, computed from Helix's published Thiele-Small. That is Helix's own recommended sealed volume.

Helix measures the SVC2 and the DVC2 separately rather than publishing one set of parameters for both, but on this model they land on the same recommended volume, 14 litres. That is what this cabinet is cut to, giving Qtc 0.862 with the SVC2 and 0.833 with the DVC2.

Do not be thrown by the F3. Half power lands at 53.3 to 54.8 Hz anechoic, before any cabin gain. Helix's own datasheet prints 46 Hz for this driver, which is a different measurement rather than a disagreement: their figure is quoted with their recommended 45 Hz, Q 1.3 highpass applied, and a filter at that corner lifts the response enough to move the half-power point down to meet it. The number above is the raw sealed response of this cabinet.

On impedance: The IK W series comes in two coil versions and they wire differently. The SVC2 is a single 2 ohm coil, so one driver presents 2 ohms and there is nothing to decide. The DVC2 carries two 2 ohm coils: in parallel that is 1 ohm, in series 4 ohms. Pick the one your amplifier is rated for, and note that 1 ohm needs an amplifier that says so.

This cabinet is 29.45 inches wide rather than the 30 inches a Proline X down fire normally runs. That is deliberate. A 30 inch footprint holds more air than the IK S10 wants, and a sealed driver in too much air loses damping rather than gaining depth, so the cabinet is cut narrower to land on Helix's volume exactly.

Measure before you order. This cabinet is 29.45 inches wide by 15 deep and 4.83 tall in the down fire position.

Before you order

Questions

Will this fit the IK S10 SVC2 and the DVC2?

Yes. The two coil versions share a frame, a 9.0100 in cutout and the same 3.33 in mounting depth, so the cabinet fits either. Helix measures the SVC2 and the DVC2 separately rather than publishing one set of parameters for both, but on this model they land on the same recommended volume, 14 litres. That is what this cabinet is cut to, giving Qtc 0.862 with the SVC2 and 0.833 with the DVC2.

Why 0.49 cubic feet net?

Because that is the sealed volume Helix publishes for this driver, 14 litres, and it is a net figure in their documentation exactly as it is in ours. Each chamber is 0.54 cu ft gross before the driver's displacement.

What amplifier power should I run, and what impedance?

The Helix IK S10 is rated 300 watts RMS each, so 300. The IK W series comes in two coil versions and they wire differently. The SVC2 is a single 2 ohm coil, so one driver presents 2 ohms and there is nothing to decide. The DVC2 carries two 2 ohm coils: in parallel that is 1 ohm, in series 4 ohms. Pick the one your amplifier is rated for, and note that 1 ohm needs an amplifier that says so. Aim for roughly 210 to 300 watts at whichever impedance you wire to.

Why is your F3 higher than the one on Helix's datasheet?

Half power lands at 53.3 to 54.8 Hz anechoic, before any cabin gain. Helix's own datasheet prints 46 Hz for this driver, which is a different measurement rather than a disagreement: their figure is quoted with their recommended 45 Hz, Q 1.3 highpass applied, and a filter at that corner lifts the response enough to move the half-power point down to meet it. The number above is the raw sealed response of this cabinet.

Why is this narrower than your other down fire cabinets?

What is the expected low-frequency extension?

Half power lands at 53.3 to 54.8 Hz anechoic, before any cabin gain. Qtc is 0.833 to 0.862. These figures exclude cabin gain, which in most vehicles adds real output below 40 Hz, and they exclude any DSP you choose to run.

Do I need to add polyfill or damping?

No. Polyfill is already installed as a light wall lining and the quantity is chosen so it does not change the acoustic volume. Do not add more.

Is the driver included?

No. This is an enclosure only. You receive the cabinet finished in plush black carpet, with threaded inserts at the driver position, stainless machine screws, one side-mounted pre-wired terminal cup, the feet uninstalled and the polyfill lining already installed.

Same series, same size