Performance Optimized · Datasheet
Helix IK S12 Dual Box: Sealed 12" Shallow Down Fire Enclosure Dual 12" Sealed enclosure
- Net volume
- 1.55 cu ft total, 0.78 per driver
- Max mounting depth
- 3.76 in required by the driver
- Cutout
- 10.9000 in
- External dimensions
- 30.00 in W × 10.34 in measured in the down fire position H × 15 in D
- Front baffle
- 1.5 in, double baffle
- Best For: Dual Helix IK S12 Floor-Firing Builds
- Net Volume: 0.78 cu ft per driver (0.87 cu ft Gross per chamber)
- Alignment: Qtc 0.753 to 0.806, fc 55.7 to 60.4 Hz, F3 52.5 to 53.9 Hz anechoic
- Driver Match: Pair of Helix IK S12 (matched), SVC2 or DVC2
- Impedance: 1 or 4 ohm with SVC2; 2 ohm with DVC2
- Construction: Dual Chamber | 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 S12 SVC2 or DVC2, quantity 2. Direct fit |
| Configuration | Dual 12 inch, dual chamber sealed down fire |
| Mounting Position | Trunk or cargo floor, cone firing downward |
| Firing Direction | Downward into the floor. Feet included, uninstalled |
| External Width | 30.00 in |
| External Height | 10.34 in measured in the down fire position |
| External Depth | 15 in |
| Internal Volume, Gross | 1.74 cu ft total, 0.87 per chamber |
| Internal Volume, Net Acoustic | 1.55 cu ft total, 0.78 per driver |
| Alignment | Qtc 0.753 to 0.806, fc 55.7 to 60.4 Hz, F3 52.5 to 53.9 Hz anechoic |
| Helix Recommended Volume | 22 litres net, which is what this is built to |
| Driver Cutout | 10.9000 in |
| Driver Mounting Depth | 3.76 in required by the driver |
| Power Handling | 600 watts RMS total across the pair |
| Floor Slot Ratio | 0.74 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 | Full chamber divider |
| 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 | 37.3 lb |
| Warranty | 1 Year Limited |
| Built In | Tullahoma, Tennessee |
Modelled response
Performance in this enclosure
01Is it a sealed driver?
Efficiency bandwidth product places the motor before anything else is decided.
02What the box does to it
0.78 cu ft against a 37.0 L Vas.
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 8.0 mm — and a bigger one once a subsonic filter stops it wasting travel below the passband.
| Param | Value | Unit | Note |
|---|---|---|---|
| Fs | 34.00 / 36.00 | Hz | free-air resonance |
| Qts | 0.460 / 0.480 | SVC2 / DVC2 | |
| Vas | 37.00 / 40.00 | L | equivalent compliance |
| Sd | 523.0 | cm² | effective piston area |
| Xmax | 8 | mm | one-way linear travel |
| Pe | 300 | W | continuous RMS |
| SPL | 86.5 | 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
0.78 cubic feet net per driver at Qtc 0.753 to 0.806 and F3 52.5 to 53.9 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, 22 litres. That is what this cabinet is cut to, giving Qtc 0.753 with the SVC2 and 0.806 with the DVC2.
Do not be thrown by the F3. Half power lands at 52.5 to 53.9 Hz anechoic, before any cabin gain. Helix's own datasheet prints 39 Hz for this driver, which is a different measurement rather than a disagreement: their figure is quoted with their recommended 35 Hz, Q 1.5 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 a pair wires differently in each. Two SVC2 drivers, each a single 2 ohm coil, give 1 ohm in parallel or 4 ohms in series. Two DVC2 drivers give more choices; the sensible target is 2 ohms, reached by wiring each driver's coils in series for 4 ohms and then the pair in parallel. Every driver in the cabinet must be wired identically, and 1 ohm needs an amplifier rated for it.
Measure before you order. This cabinet is 30.00 inches wide by 15 deep and 10.34 tall in the down fire position.
Before you order
Questions
Will this fit the IK S12 SVC2 and the DVC2?
Yes. The two coil versions share a frame, a 10.9000 in cutout and the same 3.76 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, 22 litres. That is what this cabinet is cut to, giving Qtc 0.753 with the SVC2 and 0.806 with the DVC2.
Why 0.78 cubic feet net per driver?
Because that is the sealed volume Helix publishes for this driver, 22 litres, and it is a net figure in their documentation exactly as it is in ours. Each chamber is 0.87 cu ft gross before the driver's displacement.
What amplifier power should I run, and what impedance?
The Helix IK S12 is rated 300 watts RMS each, so 600 across the pair. The IK W series comes in two coil versions and a pair wires differently in each. Two SVC2 drivers, each a single 2 ohm coil, give 1 ohm in parallel or 4 ohms in series. Two DVC2 drivers give more choices; the sensible target is 2 ohms, reached by wiring each driver's coils in series for 4 ohms and then the pair in parallel. Every driver in the cabinet must be wired identically, and 1 ohm needs an amplifier rated for it. Aim for roughly 420 to 600 watts at whichever impedance you wire to.
Why is your F3 higher than the one on Helix's datasheet?
Half power lands at 52.5 to 53.9 Hz anechoic, before any cabin gain. Helix's own datasheet prints 39 Hz for this driver, which is a different measurement rather than a disagreement: their figure is quoted with their recommended 35 Hz, Q 1.5 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 two separate chambers instead of one shared one?
A shared chamber lets each cone modulate the other's air load, which makes the pair less predictable under hard excursion. A full divider gives each driver its own sealed volume, so both behave exactly as the single version does.
What is the expected low-frequency extension?
Half power lands at 52.5 to 53.9 Hz anechoic, before any cabin gain. Qtc is 0.753 to 0.806. 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.
Are the drivers included?
No. This is an enclosure only. You receive the cabinet finished in plush black carpet, with threaded inserts at both driver positions, stainless machine screws, one side-mounted pre-wired terminal cup, the feet uninstalled and the polyfill lining already installed.
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