Another G Chang takes its first steps

[Justin Wake]

.. actually, this happened a good few months ago now, I'm beginning to feel rather guilty about not posting this sooner. Thanks to everyone involved in coming up with the G Chang design - if you had anywhere near as much fun designing it as I've had building and listening to it, I envy you.

This was my first DIY audio project - I had originally been planning some sort of simple 2-way bookshelf speakers, but as I already own a pair of B&W DM602S2s (and my father owns Quad 11Ls) I thought I'd try something completely different. Originally I started looking at some of the FE126/127 based designs along the lines of the Frugelhorn, but decided that the (relative) simplicity of the cabinet design for the BIB and Chang designs appealed to my amateur side. From there, it was a sort of 'what the hey, why not' decision to go for the 206e over the smaller drivers (not to mention that my taste includes a fair bit of bass-heavy electronic music), and a few weeks later my drivers turned up on my doorstep.

Obviously I couldn't contain myself - I grabbed the nearest cardboard box I could find and carefully stabbed a 206e-sized hole into it with a nearby pair of scissors and lowered a driver into it, powered straight from the headphone output of my iPod via a butchered cable from a dead pair of headphones:


I gotta admit, I spent a good half hour crouched over my cardboard box just listening to the driver in action - I could probably have left it at that and been pretty satisfied, but I digress.

Somewhere around 4 months later I finally got around to taking some time off work to go down to my grandfather's place (a longtime hobbyist woodworker) and start cutting up wood. Unfortunately, being in Australia, and the isolated end at that means plywood seems to be horribly expensive in the quantities I needed, so I've made do with MDF; after seeing bobtrancho's Half Chang build I was quite taken with the style of finish he used, so I chose accordingly - plain MDF (to be painted) for the centre, and MDF pre-veneered with a nice Tasmanian Oak for the sides.




All up it took us around three or four days of work (spread over a couple of weeks, mind you) to handle the cutting and gluing. I ended up fabricating some bases out of picture frames for the speakers to sit on after I discovered a few.. errors.. in the gluing that led to the speakers not quite being square, but I'm pretty happy with how it turned out for a first effort.

The painting of the centre part was done by foam roller, with a spray varnish done over the wooden sides and veneer strips down the edges.



Eventually I gave in to my impatience and declared them finished, and mounted the drivers and BSC circuit, taking them for a spin first on a lightly modded T-Amp and then my father's Harman Kardon. I have to admit being shocked by the result - I honestly wasn't expecting the wall of bass they poured out! I had a couple of typical Pendulum tracks sitting on my iPod for testing (I'm not much of a D&B fan for listening, but boy do they ever give your bass a workout), and I swear I heard it go deeper and clearer than the sub in our HT setup. Magnificent!

My girlfriend insisted on taking some 'glamour' shots of the speakers once she pried me away from the volume control - she did a fairly good job of covering up my slightly spotty painting skills.



Downsides? Well, being my first build, the woodwork isn't exactly fantastically neat, and the paintjob shows streaks in places where I had a hard time reaching, but I decided that in the end, in a moderately lit room it's not going to be apparent enough to worry me.

I didn't put enough bracing in the center chamber, which I suspect is going to bite me in the *** at some point - I might see if I can find a way of fitting some in through the driver hole at some point.

There's still a slight peakiness in the treble, which I intend on fixing at some point by fitting phase plugs and maybe tweaking the BSC a little more.

Beyond that, I'm really happy with the way these turned out. All up, expenditure was somewhere around AU$750 (drivers $300, wood $200, glue and paint ~$150 because I used so much of it, terminals/BSC/wires/misc tools etc ~$100) and sonically they thoroughly outclass my B&Ws which cost me a bit more.

Again, thanks to everyone involved in the design of these speakers!

I've already bought myself half the parts for a TubeLab SimpleSE amp and a pair of F4s to power them with.. now if only I had more time to build them..

[loninappleton]

Congratulations on the new build.

I don't recall the changs being shown in contruction stage (or maybe missed the Tranco site.

The BR section looks to be modular with the BVR as separate construction. This looks to have good flexibility though you prob'ly won't be taking them apart.

[Scottmoose]

Nice work. Glad you like them. Makes it all worthwhile to know that they give people some enjoyment.

[AnaKinDV8]

Question for Scott (or anyone who would care to help out), will the Half Chang or G Chang work with the older Fostex 207? How does that driver compare to the 207E?

[Scottmoose]

Should do to the first, no idea for the second. Never heard it.

[adawson68]

I like the speakers very much .. would be interest in the little details like how much stuffing, BCM etc

[Godzilla]

Looks really good. Enjoy them!

[Scottmoose]

Originally posted by adawson68
I like the speakers very much .. would be interest in the little details like how much stuffing, BCM etc

As detailed elsewhere. Line the driver chamber with 1in wool flet on opposing surfaces, or, if you want a more damped sound, every surface apart from the front baffle.

[adawson68]

Originally posted by Scottmoose


As detailed elsewhere. Line the driver chamber with 1in wool flet on opposing surfaces, or, if you want a more damped sound, every surface apart from the front baffle.

Thanks Scott ... lots to read and sometimes hard to find stuff and that helps me being a complete noob

I was interested in the dampening Justin is using as he seems to have stuffed with polly fibre as well or instead .. I suppose that might be down to taste.