Kinnara
SB Acoustics' open-source two-way floorstander: an 8-inch paper-cone woofer under a 25.4 mm aluminium dome, in a 1098 mm walnut cabinet whose drawings are published in full.
About the Kinnara
The Kinnara is one of the designs SB Acoustics publishes as open source, alongside Tifa 6, Tifa 8 and Bromo. The drawings are in the open — overall dimensions, panel thicknesses, rebate depths, driver cut-outs, even the damping cut to size. You can take them to a cabinet shop, or buy the cabinets ready-made from the factory and skip the sawdust.
It is a two-way floorstander. Per cabinet: one 8″ SB20PFCS30-7 paper-cone woofer and one SB26ADC-C000-4 25.4 mm aluminium dome. The cabinets are supplied as a pair in walnut veneer matt, without grilles, and the crossover comes as a set alongside them.
No exotic cone material and no origin story attached to it. A paper cone, an aluminium dome, and a drawing anyone can read — which is a fair description of how most good speakers were made before the marketing department got involved.
Its lines are drawn tall and narrow: 1098 mm high on a footprint 330 mm across. There is a slanted internal panel set at 10°, so no two opposite internal surfaces are parallel down the length of the box.
The two drivers
Woofer — SB20PFCS30-7, 8″, 7 Ω. SB Acoustics describes it as a 30.5 mm voice coil on a paper cone with a rubber surround, a round-mount injection chassis, and an acoustic-suspension application. The 7 Ω is not a typo on our part; that is the impedance the part is listed under.
Tweeter — SB26ADC-C000-4, 4 Ω. A 25.4 mm aluminium dome on a ferrite motor with an injection-moulded faceplate. Aluminium rather than the textile and beryllium domes further up the range, and priced accordingly.
We hold no published Thiele-Small set for either part. Neither carries parameters in the SB Acoustics catalogue we work from, and there is no datasheet for either in our files. Rather than fill the gap with something plausible, here is the gap — if you need the numbers to model the box, ask and we will get them from the factory. Everything we do hold is in the SB Acoustics driver catalogue.
The cabinet, as drawn
Every figure here is read off SB Acoustics' drawing rather than copied from a spec sheet, so treat it as a drawing reading. Two of them check each other: 294 mm of internal width plus two 18 mm side panels is 330 mm, which is exactly the overall width given. The depth is the one we would re-measure before cutting anything.
| Dimension | As drawn |
|---|---|
| Overall height | 1098 mm |
| Overall width | 330 mm |
| Overall depth | 270 mm |
| Panel thickness | 18 mm |
| Internal width | 294 mm |
| Internal panel | Set at 10° |
| Tweeter cut-out | Ø100.7 mm, Ø88.5 mm bolt circle, four Ø7 mm holes, rebated |
| Woofer cut-out | Ø189 mm, Ø207 mm bolt circle, six Ø7 mm holes at 45°, rebated |
Both cut-outs are rebated, so the driver frames finish flush with the baffle instead of standing proud of it. The drawing also notes that its dimensions are taken before painting, with depth the exception, and assumes half a millimetre of paint.
The damping is specified, not left to you
Most plans stop at “line the box with wadding”. This one gives you four pieces of 20 mm Dacron, cut to size, each with the surface it belongs on — and a cut pattern for laying them out on the roll.
| Piece | Size | Qty | Where it goes |
|---|---|---|---|
| A | 1300 × 290 mm | 1 | One layer over the top and back |
| B | 800 × 290 mm | 1 | One layer over piece A and the back |
| C | 800 × 180 × 40 mm | 2 | Two layers, left and right side panels |
| D | 900 × 125 mm | 2 | Two layers, over piece B and the front |
All four are specified as 9 oz white Dacron, 20 mm thick. Piece C is a taper rather than a rectangle — 180 mm at one end, 40 mm at the other — because it follows the slanted internal panel.
What this page does not tell you
The other kit pages here carry a specifications block — frequency range, sensitivity, nominal impedance, crossover point, port tuning — because SB Acoustics publishes those figures for those models. For the Kinnara, the documents we hold are the build drawings and the parts list, and nothing else. So there is no specifications block on this page, rather than one filled in by analogy with a kit that happens to use a similar driver.
Nor is there a photograph. What you can see above is the drawing set, which is at least honest about what arrives on the pallet. Ask us and we will chase the factory for the measured response and a picture of a finished pair.
Come and listen.
Bring your favourite tracks. Leave with something you'll keep for decades. No pressure, no commission-chasing.