Helix IQ W8 Box: Sealed 8" Down Fire Enclosure Single 8" Sealed enclosure

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.

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.

The Helix IQ W8 is rated 750 watts RMS each, so 750, and that does not change with the Tuning Mass setting. The IQ series ships in one coil version, the DVC2: two 2 ohm coils on one 63 mm former. 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 525 to 750 watts at whichever impedance you wire to.

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.

Some of these are narrower than the 30 inches a Proline X down fire normally runs: no added mass at 11.90 in, +1 mass ring at 15.99 in. That is deliberate. A 30 inch footprint holds more air than the lower Tuning Mass settings want, 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.

Half power lands between 38.9 and 67.7 Hz depending on the setting anechoic, before any cabin gain, with Qtc from 0.681 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.

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.

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 the driver position, stainless machine screws, one side-mounted pre-wired terminal cup, the feet uninstalled 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.