New speakers

VTip5I just ordered the parts for some new desktop speakers. They’re called ER18DXT. I discovered them about a year ago, and wanted ‘em ever since.

Because of their American origin I had to make some modifications to make these work in my European mind.

Enclosure

Obviously I converted the imperial dimensions to metric units and rounded the values accordingly. Baffle dimensions will be kept as in the original design, however I’ll build the speakers into closed 12 liters, since I’ll  be using a subwoofer. Taken the resistance of the woofer inductor into account, this results in a Qtc of ~ 0.65, which makes the ER 18 RNX roll off around 80hz. This should be an excellent match to the sub.

In case you are wondering the picture was made with Google Sketchup. I followed the Sketchup for Woodworker Tutorial to learn the basic steps. It’s fairly easy after that. I highly recommend the Cutlist plugin which surprisingly creates cut lists for you.

Crossover

Some crossover components are not available in Europe.crossover They fall between the values provided by the E24 series. In this case I just went with the component which had the smallest deviation (usually below 7%). The picture on the right shows the deviation of the original crossover versus the modified one. Not a problem I think.

Also I opted for some cheaper components. The air coil for the woofer lowpass was replaced with a steel laminate coil which costs half as much. This shouldn’t be problem, especially since I don’t listen at high volume.

Capacitors parallel to the drivers are MKT types, the series capacitor for the tweeter is a MKP AudynCap.

Once the parts have arrived I’ll measure the driver dimensions myself and then order the baffles accordingly. In the meantime, I’ll think about which veneer to apply.

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