In my quest to maximize the quality of the music that originates from my Macbook Pro, I first started off with the DAC component previously reviewed. While I feel the Aune X1 made a huge improvement in sound, it’s not much of an argument to suggest that the speakers themselves will have the largest impact. As such, I contemplated for sometime what to do to replace the venerable AudioEngine 2′s that I’ve enjoyed for about a year. Don’t get me wrong, for their size and price, I’m not sure anything can match those little babies.
But in order to find an ideal complement to the DAC, I was looking as several monitor type speakers that ranged anywhere from $500 to over $2000. Again, I had to remind myself, the goal of this project was to gain the best possible sound at the lowest possible cost. So while I was considering this, I had the epiphany to make my own speakers..At first, I considered the traditional wood/MDF cabinets, but I felt that route was too boring.. been there..done that. I wanted something different. Something more creative. Something that is a culmination of all my past handyman efforts.
The issue with wood speaker cabinets is that it’s very difficult to stabilize/brace them internally to minimize resonance. Theoretically, you want the cabinets to “vibrate” as little as possible. For the price, I cannot think of anything more dense than concrete to achieve this goal (on an unlimited budget, I suppose cabinets made out of solid Osmium or Iridium would be better…but that’s a project for another day=).
Now, I consider myself a bit of an artist. Recently, I’ve gravitated to the organic and rustic beauty concrete has to offer for sculptures and furniture. Recently, I’ve built a bathroom vanity as well as an 11 foot concrete countertop for my bar. But building a one-piece enclosure is a very daunting task…The tolerances for a speaker cabinet need to be very precise if you want a clean look with the drivers mounted flush with the surface. You can’t exactly take out a plunge router after the fact like you can with MDF or plywood. All these things need to be planned out in advance.
I don’t want to get into too much detail about the construction, but let’s just say that for a first attempt, I think I did ok (despite some near disastrous incidents that I don’t care to talk about right now).
After some research, I settled on the RS621 kit from Parts Express. The Dayton Audio tweeters seemed to be inspired in design by some ScanSpeak tweeters that I’m familiar with but at a fraction of the cost. In total, the drivers with assembled crossovers cost just over $400 (USD) delivered to Canada. So it was right in my price range of being sub $500..While waiting for shipment, I pulled out the specs and fabricated the cutouts for the drivers out of acrylic and 1″ plywood. The cavity of the enclosure was cut from rigid stryrofoam.
Above is a picture of a speaker just prior to releasing the form. I used 1/4″ metal rods to the pour for the binding posts. While I thought the acrylic and the plywood would release easily, I was quite mistaken. I literally had to hack away at them with a chisel. But after an hour or so, I managed to chip away and remove all the Styrofoam cavity lining as well…Thereby creating a seamless enclosure. The design I went with using the drivers is a sealed design. I may tackle a larger vented/ported speaker project sometime in the future.
When working with concrete, it’s important to understand it’s crystalline properties. After about 3 days, the form can be safely released and the rough grinding can begin. I have a diamond cup wheel that I used for the back (speakers were poured with drivers face down), and polished the remaining surfaces from a 50 grit all the way up to 3000 grit diamond resin pads using my wet Fein polisher.
Polishing from 50 to about 800 was done within the first two weeks. The final polishing was done about a month after the initial pour..Why? well, concrete gets progressively harder over time..In fact even after 100 years, if only minutely each year. But for all practical purposes, it reaches it’s maximum hardness in about 27-28 days. At this age, the high polish pads do a great job creating a sheen that is close to polished granite. I chose not to wax or seal the final finish.. I purposely want a more organic semi-gloss lustre. I added sue black and green dye into the mix to give it some colour.
This was a project that suited to my anal retentiveness. Without this valuable skill set, I could not have created the flush mount exactness I was looking for.. I would say less than 1/100th of an inch all around the flange of the drivers. Near perfect fit. Above is a picture of the taps for the driver bolts. I replaced the ones that came with the kit with M3 cap machine hex-head screws instead. If you’re wondering, I cast 1″ sections of aluminium rods as part of the form. That way I would not have to drill into concrete for the speaker screws so close to the edge and risk breakage. I think they worked out well. With the foam and polyfill installed, the final assembly is almost complete.
With the units assembled, the anticipation was too much for me. I lumbered these 50lb (each) babies to my main stereo room and hooked them up to my ancient Classe SSP75 and Parasound 2205 amp. I should have let them burn in a bit, but I was still blown away to be honest. Vocals are crystal clear and a surprising amount of base for a sealed unit and the 6″ woofers. I will be using these primarily in my office and I will not be matching them with a sub so very happy with the Dayton drivers. I imagine that over time, the units will sound even better. I am currently using the Aune X1 for the DAC, which then flows to the Aune X2 amp. I have not yet taken the time to give the X2 a proper review, but so far, i am very impressed with the little guy. For a solid state amp of this size and price, it’s terrific., however, at very low volume, I notice that the right speaker is a touch louder than the left. I will keep my ear on this to see if it persists. I will let the speakers and the X2 warm up for about a month before I give a fair assessment. But I don’t imagine my mind will change too much. With my concrete speakers, the Aune X1 and the Aune X2, I think I have the perfect set up for my needs and at the best possible price. Aside from my labour (which is really worth thousands…seriously), total costs of my office set up is roughly $700.
As an aside, I will soon tackle my winter project to build a 35W/channel tube amp that I hope to use to drive these speakers sometime in the next few months.
I hope I didn’t disappoint anyone by not giving a detailed review of the speakers themselves. That’s because these are not available at any store at any price. You just have to trust me that they sound great… Far exceeded my expectations and they certainly won’t be my last. But I trust you enjoyed reading nonetheless.