Construction:
The box is based on coffee bean barrels that I got from Lidl. The back has a series of 1~2mm drilled holes, partly blocked off with a layer of craft-shop felt. The purpose of this was to produce an aperiodically vented enclosure, overcoming the limitations of a sealed box (standing waves that put pressure on the cone at a series of nodal frequencies).
The matte brown was achieved with a couple of layers of wood dye/mordant. And I decided to keep the tattoo-like Arabica branding, because why not? The dye seemed to offer its own protection so I skipped the lacquer.
Vent design
Having once “overdone” a similar style of vent, which required extensive adjustments to reduce airflow, this is what I came up with. Note how the holes are concentrated around the rear corner, where I expected the sound waves to converge to the highest pressures inside the box.
The sound
The speaker itself seems to have a natural tendency to beam at high frequencies. As mentioned in another post, the ‘niceness’ in the upper registers is at least partly dependent on the amplifier, with a current-source MOSFET being the silkiest/smoothest, followed by series resistance (a ridiculously simple hack that trades excess power that would never get used anyway for subtly cleaner sound), followed by direct-connected class-D as the harshest. Despite having access to digital filters on PC, I was unable to replicate these sort of tonal differences by adjusting EQ, leading me to believe that other factors like non-linear distortion must be at play.
The speakers start running out of puff around 200Hz, and, the +/-2.5mm Xmax rating seems a little ambitious, although in this case the box was never designed to produce bass.
Holding and rotating the speakers in your hands while playing something, it’s possible to hear some interesting effects/artefacts. There is some cancellation, but it’s quite subtle and nothing compared to running the speaker in dipole mode. Overall, it’s very pleasing and mellow.
Take 2?
Given the same speakers, or similar ones, what would I do differently next time around? I’ve actually got 9 similar sized speakers waiting for me (2 bought, 7 salvaged from a 7.1 system), so it’s not an idle question.
Top contenders:
- A mini transmission line could be cool. It could be interesting to get some DEEP BASS extension with the help of some creative box tuning.
- Egg-shaped boxes based on all-natural coconut shells — a great option for portability.
- Open baffle plywood panels — another great option if you need an excuse to up-size your living space.
Or: none of the above, or at least not exactly. Using Hornresp, my TL models keep transforming into back-loaded horns, favouring higher sensitivity over a low cut-off frequency. There are a lot of unknowns in it for me, which makes this option all the more appealing.