Continuous max SPL:
Est. build cost:
|Single driver, vented|
Very small stand-mount/bookshelf
60 Hz-20 KHz (in-room)
87 dB / 2.83 V / 1 meter
103 dB (pair, 1 meter, from 60 Hz)
Something else that I recommend is to chamfer the inner opening of the driver cutout, for better airflow. Use a small round over router bit to do this, but save some wood around where the T-nuts and screws will go.
Important note: If you have the version of the driver with the round chassis and want to build this design, you can still do it. How much you need to change depends on how you will build it. If you intend to use separate side panels as I did, you need to make the center cabinet part 15 millimeters wider and 20 millimeters less deep. You will need to adjust your parts diagram yourself, but just keep in mind that the port length shouldn't change and only the total width and depth of the whole cabinet. This will make the port throat opening a bit smaller but the effect is negligible. The baffle will now have room for the full round cut-out (125 mm).
However, if you will build the whole thing as a solid part with the sides glued on, you can just keep the original width + the sides and route into the sides to fit the whole round driver.
Not so much a crossover as some equalization and impedance compensation. No need to get complicated with these drivers.
The final filter I used. Even if you vary the baffle size +- a centimeter or two this would still work. Just don't place the driver any differently.
You could get a flatter response with a few notches but having more stuff in the signal path would take away the "full range" driver benefits.
Use air-core inductors and metal oxide resistors. The biggest cost here is the inductor.
Decent sensitivity at 2.83 volts. A bit ragged top end but there is no harshness what so ever with these drivers.
The impedance and electrical phase will not pose a problem for, well, anything.
The end result was great. They definitely sound good, and the bass was surprisingly potent and well-defined. You can use them without additional bass-support for sure. Just place them a bit closer to a back wall. Now, they are no reference monitors. They do paint a beautiful picture, albeit not necessarily a realistic one. I would still call them neutral though, not really favoring any kind of music genre, doing a good job with all of them.
They can take some punishment and play fairly loud before distortion sets in due to the coil traveling outside the gap. The linear Xmax is a well generous 6 mm p-p, and this is what will limit you. I have tried everything from a T-Amp (not bad, but not loud either) to an integrated Rotel up to my current Behringer A500 which works like a charm.
The ultimate verdict: They would fit best for smaller rooms. Personally, I used them as my main speakers in my fairly large living room (58 cubic meters) and I could not really complain considering their size. Either way, they're cheap, they're good, and they're easy to build. If you are looking for a good first project, this might just be the one for you.
As is evident I didn't follow my own advice of rounding over the edges of the sides. But I later changed the side panels to some thinner pine ones and rounded those over. The leather turned out great and helped hide my bad routing for the driver recess. If you decide the use leather finish, keep in mind the thickness and add that to the sides so that they match up.
As you can see the voice-coil is very small but that's under hung for you. It's really the only way to get good excursion on a full range driver that needs to maintain a low moving mass in order to produce the highest frequencies.
The copper sleeve reduces the already low inductance and improves linearity. The clearances in the magnetic gap are extremely tight and much better than I have seen on any expensive phase-plugged driver such as the Seas Excels. Pretty cool.
Emil Attlid © 2008