Baby Audax

[SimonC]

I've had a few 4" audax carbon fibre mid-range drivers kicking around for a while (the HM100C0 ones) and I've been promising the kids that I'd make them a mini-hifi...and with Owston on the way as well it seemed like a good excuse to make some sawdust.

I'm experimenting with a couple of different designs to bring along, just to see what happens really.
First one is a vented box, close to the volume and alignment in the audax datasheet with a little tweaking using Martin Kings sheets to give a pretty flat response.
Second is an MLTL, using Martin Kings sheets and Bob Brines approach to optimization.

Don't know what to expect in the way of differences between the two, the sims say there should be, but especially in audio the reality can be something very different...

Anyway, after being able to grab a couple of hours on a CNC router yesterday sawdust is underway

[Dave the bass]

*Adds CNC router to Christmas 'wants' list*

Nice work MrC.

DTB

[SimonC]

Managed to get a day yesterday in the sawdust factory

Nearly finished, just need a run over with the sander.

One of the things that the CNC lets you do very easily is the comb style joint and get perfect alignment. I've been experimenting using these on the panels with a very slight interference fit so that the joints hold themselves together to save pins, biscuits or clamps while gluing.

This works a treat, just tap the panels together with a mallet, then use a clamp to pull them tightly into their final position. Once they are all pulled up snug its rock solid. The disadvantage is you need to machine fillets (dog-bones) in the corners of all the tabs and rebates (CNC always leaves a corner radius on inside corners...) and you have to zip round and fill these once its assembled.

Another dead easy thing with CNC is stacking panels etc with alignment dowels, also makes laminated construction a doddle.

[SimonC]

last pic for today

[Dave the bass]

.... Even the sawdust is shoddy... Pffffft!

[IslandPink]

That post from 7:31am comes perilously close to gloating !

[Greg]

Nice one Simon. As I use these drivers in my KLS3's, I'll be very interested to hear them at Owston. Looking forward ðŸ‘￾

[pre65]

[SimonC]

That post from 7:31am comes perilously close to gloating !

It was not supposed to...

I've had a couple of questions about CNC, so I thought I'd try and keep it all in one thread and give a bit of info about the construction as I go. CNC does make some things easy that with traditional wood working are quite tricky (and beyond my skills), such as comb joints and multiple dowels, but it also has drawbacks. Some of these are you need to make things from flat sheets, it won't do sharp inside corners, and the programming & set-up takes a good while. (Although I'm getting quicker).

[SimonC]

[SimonC]

Both pairs finished and ready to rock.

First impressions have been curtailed as I broke my LMS server and its taken a few days to figure out how to get it working again. (Beware of Ubuntu 14.04... I'll post the problem and the fix on a separate thread.)

At the moment they are powered by a TDA chip amp with a Pi/Hifiberry DAC at the front end to get them going. Long term plan is a simple P-P valve amp, as with most small drivers they need a good few watts to get them going.

Owston here we come (plus their big cousin the A12 MLTL's)

[pre65]

Long term plan is a simple P-P valve amp, as with most small drivers they need a good few watts to get them going.

Hi Simon, my 832a PP amp is simple and cheap.

I can bring it to Owston if you would like to try it with your speakers.