MemberNovember 5, 2021 at 10:16 am
So… I finished them but it was a rocky road.
This was the 2nd main prototype
The 3rd which was to match split very quickly and badly – I hadn’t completely covered the outside so the MDF shrank – I think it was 10mm shorter than the one above!
Eventually, the 2nd started to split too – when I took the drivers out, the inside must have dried out and shrunk.
I’m all in at this stage, I’ve spent about £1000 on drivers and about £400 on crossover parts.
I went back to the guy I’d found to CNC the slices for me and he suggested moisture resistant MDF.
So I did 4 things (which is never great when diagnosing a problem):
1) Used MR MDF
2) Left every slice to acclimate in my living room for 2 weeks.
3) Sprayed Shellac-based primer inside and out of every slice (64 in each speaker)
4) Built each speaker in sections
However, I used the threaded rod again and clamped all the sections together to bodywork the whole speaker in one go.
When they were perfectly sanded (about a months work) I undid the rod and split them:
Then I put based coat and clear coat while they were together again, then split them for colour sanding and machine polishing.
I used some 2mm foam sheet cut to match the profiles. Here you can see the rounded over joins as I’m building them upside down in the kitchen!
Here’s the top after some colour sanding and machine polishing:
In situ side view
I’ve started prototyping the centre speaker:
They sound epic. I had to give them a nice new amp so a 400W/channel Lyngdorf 2-channel was purchased.
They were built to be non-ported and tuned to about 45Hz but with some Dirac Live DSP, they’re able to drop to 32Hz