




Performance Optimized · Datasheet
Helix IQ W8 Dual Box: Sealed 8" Wedge Enclosure Dual 8" Sealed enclosure
- Net volume
- 0.26 to 0.88 cu ft per driver, by setting
- Tuning
- No Added Mass, +1 Mass Ring, +2 Mass Rings. Each is a different cabinet, cut to order
- Max mounting depth
- 4.51 in required by the driver
- Cutout
- 7.2100 in, same at every setting
- External dimensions
- 22.05 to 32.00 in across the settings W × 11 in at the seat face H × 10.76 to 16.62 in at the base D
- Front baffle
- 1.5 in, double baffle
- Best For: Dual Helix IQ W8 Trunk-Fit Builds
- Net Volume: 0.26 to 0.88 cu ft per driver by Tuning Mass setting
- Alignment: Qtc 0.659 to 0.695, fc 38.2 to 62.9 Hz, F3 38.9 to 67.9 Hz anechoic
- Tuning Mass: 3 settings offered, cut and built to order
- Driver Match: Pair of Helix IQ W8 (matched), DVC2
- Impedance: 2 ohms with each driver in series, pair in parallel
- Construction: Dual Chamber | Rear-Firing Wedge | V-Groove/Dado | Double 1.5" Baffle | Threaded Inserts
Spec of record
Technical specifications
| Specification | Value |
|---|---|
| Series | Proline X Performance Optimized Wedge |
| Compatible Driver | Helix IQ W8 DVC2, quantity 2. Direct fit |
| Configuration | Dual 8 inch, dual chamber sealed wedge |
| Tuning Mass Settings Offered | No Added Mass, +1 Mass Ring, +2 Mass Rings. Each is a different cabinet, cut to order |
| Build | Cut and built to order. Nothing is pre-cut |
| Mounting Position | Trunk or cargo area, tall face against the rear seat back |
| Firing Direction | Rearward into the trunk. Not a down fire design, no feet included |
| External Width | 22.05 to 32.00 in across the settings |
| External Height | 11 in at the seat face |
| External Depth | 10.76 to 16.62 in at the base, 6.76 to 12.61 in at the top |
| Internal Volume, Gross | 0.31 to 0.94 cu ft per chamber, by setting |
| Internal Volume, Net Acoustic | 0.26 to 0.88 cu ft per driver, by setting |
| Alignment | Qtc 0.659 to 0.695, fc 38.2 to 62.9 Hz, F3 38.9 to 67.9 Hz anechoic, by setting |
| Helix Recommended Volume | 6 to 25 litres net across the settings offered |
| Driver Cutout | 7.2100 in, same at every setting |
| Driver Mounting Depth | 4.51 in required by the driver |
| Power Handling | 1500 watts RMS total across the pair |
| Impedance | DVC2, dual 2 ohm: 1 ohm parallel or 4 ohm series per driver |
| Xmax | 12 mm one way |
| 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 | 28.2 to 49.6 lb depending on setting |
| 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
0.26–0.88 cu ft against an 8.5 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 12.0 mm — and a bigger one once a subsonic filter stops it wasting travel below the passband.
| Param | Value | Unit | Note |
|---|---|---|---|
| Fs | 43.00 / 37.00 / 33.00 | Hz | free-air resonance |
| Qts | 0.450 / 0.510 / 0.600 | 0 TM / +1 TM / +2 TM | |
| Vas | 8.50 / 8.50 / 8.50 | L | equivalent compliance |
| Sd | 222.0 | cm² | effective piston area |
| Xmax | 12 | mm | one-way linear travel |
| Pe | 750 | W | continuous RMS |
| SPL | 83.2 | dB | 1 W / 1 m, derived from T/S |
Driver parameters as published by audiotec-fischer.de and the HELIX IQ datasheet. Curves computed against this enclosure’s actual net airspace.
From the shop floor
Installer's take
0.26 to 0.88 cubic feet net per driver at Qtc 0.659 to 0.695 and F3 38.9 to 67.9 Hz anechoic, depending on which Tuning Mass setting you order. Every figure is computed from Helix's published Thiele-Small for that setting.
The IQ series carries Helix's Tuning Mass System: bolt-on weights that thread onto the cone assembly and let one driver run several alignments. Each weight raises moving mass, which drops free-air resonance and raises the driver's total Q, and Helix publishes a different recommended sealed volume for every setting to keep the system in hand. This cabinet is offered in no added mass, +1 mass ring and +2 mass rings, 6 to 25 litres of Helix's own recommended volume, and across those the system Q works out at 0.70 at the base setting and 0.69 at the top of the range offered. What does not change is compliance, and therefore Vas, because mass and spring rate are independent.
The IQ W8 ships with three weights. The top setting, all three fitted, is not offered as a listed size here; call or text 931-563-5151 if that is the alignment you want and we will quote the cabinet for it.
Every one of these is cut and built to order. Nothing is pre-cut and nothing sits on a shelf waiting for a Tuning Mass setting to be chosen, because each setting is a different cabinet rather than a label on one. Pick the setting you intend to run and the panels are cut to it.
On the F3 figures: Helix prints a lower limiting frequency for every Tuning Mass setting, and ours agree with theirs to within 1.7 Hz at every setting offered here. That is worth stating because it is not true of every Helix line. The IK datasheets quote their figure with a recommended DSP highpass applied and read several hertz optimistic against the raw sealed response; the IQ sheets carry no filter recommendation and their numbers reconcile with the anechoic math. Both F3 columns in the table above are anechoic and exclude cabin gain.
On impedance: The IQ series ships in one coil version, the DVC2: two 2 ohm coils per driver. Across a pair the sensible target is 2 ohms, reached by wiring each driver's coils in series for 4 ohms and then the two drivers in parallel. Both drivers must be wired identically, and any route to 1 ohm needs an amplifier rated for it.
Marked with an asterisk: at no added mass the IQ W8 wants less air than the smallest cabinet this chassis can build. The 0.26 cu ft figure listed is what we actually cut, which is 0.05 above Helix's figure, and the Qtc shown is the one that volume produces rather than the 0.70 they publish. The cost is about a hertz of F3 and a slightly drier alignment. We would rather print the number we build.
Measure before you order, and measure for the setting you actually want. These range from 22.05 to 32.00 inches wide, 10.76 to 16.62 deep at the base and 11 tall.
Before you order
Questions
What is the Tuning Mass System and which setting should I order?
The IQ series carries Helix's Tuning Mass System: bolt-on weights that thread onto the cone assembly and let one driver run several alignments. Each weight raises moving mass, which drops free-air resonance and raises the driver's total Q, and Helix publishes a different recommended sealed volume for every setting to keep the system in hand. This cabinet is offered in no added mass, +1 mass ring and +2 mass rings, 6 to 25 litres of Helix's own recommended volume, and across those the system Q works out at 0.70 at the base setting and 0.69 at the top of the range offered. What does not change is compliance, and therefore Vas, because mass and spring rate are independent. Fewer weights give a smaller cabinet, a higher resonance and a drier, faster presentation; more weights give a bigger cabinet and deeper extension. Order the setting you intend to run, because the cabinet is cut to it. The IQ W8 ships with three weights. The top setting, all three fitted, is not offered as a listed size here; call or text 931-563-5151 if that is the alignment you want and we will quote the cabinet for it. Every one of these is cut and built to order. Nothing is pre-cut and nothing sits on a shelf waiting for a Tuning Mass setting to be chosen, because each setting is a different cabinet rather than a label on one. Pick the setting you intend to run and the panels are cut to it.
Why does each setting get a different volume?
Because Helix publishes a different recommended sealed volume for each one, and the reason is physics rather than preference. Adding mass drops the driver's free air resonance and raises its total Q, so holding system Q near reference means growing the box. Compliance does not change, so Vas stays at 8.5 litres throughout. The table on this page lists what we build for each setting.
What amplifier power should I run, and what impedance?
The Helix IQ W8 is rated 750 watts RMS each, so 1500 across the pair, and that does not change with the Tuning Mass setting. The IQ series ships in one coil version, the DVC2: two 2 ohm coils per driver. Across a pair the sensible target is 2 ohms, reached by wiring each driver's coils in series for 4 ohms and then the two drivers in parallel. Both drivers must be wired identically, and any route to 1 ohm needs an amplifier rated for it. Aim for roughly 1050 to 1500 watts at whichever impedance you wire to.
Does your F3 agree with the figure on Helix's datasheet?
Helix prints a lower limiting frequency for every Tuning Mass setting, and ours agree with theirs to within 1.7 Hz at every setting offered here. That is worth stating because it is not true of every Helix line. The IK datasheets quote their figure with a recommended DSP highpass applied and read several hertz optimistic against the raw sealed response; the IQ sheets carry no filter recommendation and their numbers reconcile with the anechoic math. Both F3 columns in the table above are anechoic and exclude cabin gain.
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 between 38.9 and 67.9 Hz depending on the setting anechoic, before any cabin gain, with Qtc from 0.659 to 0.695. 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 for the cabinet you ordered, so it does not change the acoustic volume. Do not add more.
Is the driver included, and how long does it take to build?
No. This is an enclosure only, and the Tuning Mass weights come with the driver from Helix rather than with the cabinet. You receive the box finished in plush black carpet, with threaded inserts at both driver positions, stainless machine screws, one side-mounted pre-wired terminal cup and the polyfill lining already installed. Because every setting is a different cabinet, nothing is cut ahead of time and these are built to order. Call or text 931-563-5151 for current lead time.
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