Beatrix’s enclosures December 15th, 2007

So the current box needs a needs a bit of major work. Over the course of the year quite a few things have been changed leaving holes and loose joints. So I need to apply silicone/woodglue and seal the bass enclosure. I’ll also need to add two more aero ports to accommodate the new subs which isn’t a major biggy.

The legs for the top box need to be extended by a few more centimeters and a joint added to the middle to facilitate the seperational hinges. Trouble then is finding a way to attach the legs to the bottom box in a way that’ll still allow me to completely seal and/or remove the lid if and when I need to. It’s not an easy thing to do with so much force being applied to three positions on the legs. I could glue and screen the lower half of the legs to the bass unit’s lid and screw around the legs to secure the lid to the box. Trouble is then that it lacks sufficient clamping force for all that air inside. See what I mean? The hinges need to be in the middle to provide a decent place to screw into that’ll support the lateral forces of when Beatrix goes over a pot hole.

The top box also needs upgrading with lexan polycarb as the current perspex isn’t upto the pounding of the 6 100w full range drivers, especially with such large perspex areas. The current perspex is cracking around the screws and rattling against the woodwork. The new plan is to add an aero port for that extra little bit of oomph and rubber sheeting along all the perspex/ply contact points, that’ll stop the rattling and also put less strain on the polycarb.

Drivers and amps December 15th, 2007

I’ve been wondering a while now about the whole weight versus impact issue. My planned upgrades were due to lighten Beatrix by 12kg but I’ve had a change of heart.

I could replace the Kenwood W300s subwoofers with ones rated 400w more a piece, not only that but they play lower, and go louder by 2db for any given input signal. Trouble is, they weigh 500g more each a piece, so that’s -2kg from the 12kg weight saving.

Apart from that, I’m replacing the JBL amp driving the subs with a Kenwood one that’ll do twice the power. Trouble here is that instead of running 4x 104w rms @ 4ohm, the new amp will do 1x 1000w rms @ 1ohm. Which means that it’ll be a much higher current involved, which means more power consumption. Thankfully it’s a Class D amp compared to the previous Class A/B which means it’s twice as efficient, or in laymens terms, even though it’s twice the power, it consumes the same amount of power from the battery.

I’m also wanting to replace the top amp which is an Audio System’s amp kicking out 4x 120w rms into 2ohms, which will drive the SPL Dynamic speakers quite nicely, but they would be underpowered. If I move the current JBL amp to the top, the SPL Dynamics will receive 145w per pair, which means they’ll only be underpowered by 10w per pair which is quite good actually. It’s also 15% more efficient unfortunately, it also weighs 2kg more.

What do you think?

Halloween CM London Oct 2007 October 26th, 2007



Beatrix radio linked with a tank September 11th, 2007


Plan C – The Bird September 11th, 2007

Beatrix on Space Hijacker duty at the DSEi Arms Fair.