The subwoofer is the model a car audio programme is judged by, and the hardest to choose from a catalogue — because subwoofer listings lean heavily on maximum wattage titles. The GRANVOZ subwoofer family lists 33 published models from 6 to 18 inch. This guide works through the four decisions that actually determine whether a subwoofer is right for a car programme: size, power honesty, voice-coil configuration, and enclosure support.
Decision one: size against the vehicle
Size classes in the family: 12 inch dominates with 22 models; 15 inch carries the high-power flagships; 10 inch has two models; 18 inch appears at the extreme end; and a 6 inch 800 W model covers compact installs. Bigger cones move more air per stroke, but the vehicle decides what fits: a 12 inch in a correctly sized enclosure outperforms an 18 inch squeezed into the wrong box. For most retail programmes, the 12 inch class is the volume centre — it is where the catalogue's series depth is (SUB-01, SUB-02, SUB-03, SUB-05, SUB-06, SUB-09 and SUB-10 lines) and where dual voice coil variants concentrate.
Decision two: read power like an engineer
Titles in this family carry headline wattages — up to 5000 W on the largest models — and they are not all stated on the same basis: the SUB-0912A's 1000 W title, for example, matches the RMS figure in its own description, against a 2000 W maximum. The descriptions, where the manufacturer publishes them, separate RMS from maximum: the SUB-0515A-3000W is described at 3000 W RMS / 5000 W maximum with a 4 inch BAVC voice coil and a 400 oz magnet, while the SUB-0518A is described at 2500 W RMS / 5000 W maximum. Those description figures are the ones to design against. For models without a published description breakdown, ask the sales team to confirm the RMS rating in the quotation — never size an amplifier or an enclosure from a title wattage.
Decision three: single or dual voice coil
Five listings in the family are dual or double voice coil designs, including the SUB-0112D (4+4 ohm) and the dual 4 ohm SUB-0312 listings. A dual coil lets one model serve several amplifier loads: coils in parallel halve the impedance, in series they double it. For a distributor stocking one SKU against many installer preferences, that flexibility is worth more than a small price difference. Single-coil models remain the simpler, cheaper choice for fixed programme builds.
Decision four: enclosure support
A subwoofer is half of a system whose other half is a box. The manufacturer does not publish Thiele-Small parameters in its subwoofer listings, but states that its acoustic sound testing provides T/S parameters for its speakers. Ask for the parameter set for your chosen model before your customers' enclosure designs are finalised — and ask for a sample to verify against, because a production programme built on unverified parameters is a returns programme waiting to happen.
Commercial notes
Subwoofers are bulky: packing quantities and carton sizes decide freight economics as surely as unit price. Ask for the packing specification per model, confirm the MOQ and lead time in the written quotation, and weigh the sample. Magnet weight is a real cost driver in this family — the flagship descriptions run to 375–400 oz magnet structures — so freight-weight comparisons between candidate models are legitimate engineering, not penny-pinching.
What the descriptions tell you about construction
Subwoofer descriptions in this family reward close reading, because construction is where output and reliability are decided. Voice-coil size and winding material set thermal headroom — the flagships publish 4 inch BAVC coils, with the SUB-0515A-3000W specifying a PICCAW winding 55 mm tall. Magnet weight tracks motor force and cost together: 400 oz on that flagship, 375 oz across the triple magnet stack of the SUB-0518A. Basket material separates the tiers — aluminium baskets on the high-power lines, steel on the volume lines. And the published responses of the two described flagships (35 Hz–400 Hz and 32 Hz–500 Hz) remind you these are true subwoofers: they hand over to the midrange early, so a programme that pairs them with weak door speakers will sound exactly as unbalanced as the figures suggest. Read the description as a system document, not a spec sheet, and the right pairing decisions make themselves.
A note on the slim corner
Not every vehicle gives a subwoofer a full-depth home. The catalogue's slim-titled models sit in the woofer family rather than this one — a reminder that catalogue organisation follows the manufacturer's own logic, not the buyer's search terms. If your programme includes under-seat or behind-seat installs, shortlist from the shallow mount guide on this site and confirm mounting depth per model in the quotation; depth is the one figure a slim programme cannot afford to assume.
The condensed method
- Choose the size class from the vehicle and enclosure volume, not from wattage titles.
- Design against RMS figures from descriptions; confirm them in the quotation.
- Pick dual voice coil where one SKU must serve many amplifier loads.
- Request T/S parameters and a sample before enclosure designs are frozen.
- Cost the programme on packed weight and carton volume, not unit price alone.