THAM 12 - 12mm plywood?

Yes and no, You cant keep the dimensions the same. If you were going to use 18mm you would be de scaling the horn flare, But simply you can widen the internal width between side panels so that the area of the start and end of each segment remains the same as in 15mm. Not possible with 12mm as you cant really go thinner, well not easily with this design as it will probably conflict with the driver (worth checking tho). So other option is to accept you will have scaled up the horn flare making sure that the scaling that is taking place takes place consistently, I.e top,bottom, back and all internals centred of where there would have otherwise been 15mm. (Excluding the side panels only, you can put those the same internal distance apart as the 15mm plans to minimize the scale factor) Scaling will effect the horn loading, by how much I couldn't say.

Edited by SouthwestCNC - 26 May 2017 at 3:20pm