The story of our Wood Speaker starts with our friendship with industrial designer Joey Roth. We first met in 2010 when he moved up to Portland from Los Angeles. Roth was already well known for being at the forefront of independent designers bringing their products directly to consumers through the internet. We were huge fans of his ceramic speaker; something that had been a big hit online.
SEAN KELLY: (Grovemade Lead Product Designer) I had admired his purposeful approach to audio design since I was in design school. His form always follows function; He makes things what they need to be and just that.
In early 2015, when we started tossing around the idea of making a Grovemade speaker, it only made sense to pitch him the idea of a collaboration. When we approached Joey, he was equally excited to work with us because he was interested in how we integrate design and manufacturing so closely. As the project got rolling, we started meeting at Joey’s home in NE Portland, brainstorming how we could work together to create an audio product better than anything either of us could create on our own.
JOEY ROTH: I was considering a shift in my process, using domestic production to have more direct feedback when manufacturing. Having the Grovemade guys approach me was perfect timing.
We discussed everything from portable, wireless bluetooth-speakers to multi-speaker systems with subwoofers. Ultimately, we decided to make a timeless speaker system that would avoid the digital bells and whistles of the consumer electronics arms race. We looked to create great audio through smart design and utilizing our materials to their fullest potential.
Joey then gave us a little background on wood speakers. He explained to us that manufactured wood products (MDF and plywood) are the most common material for high quality speakers because it has good acoustic properties, is consistent, and is relatively inexpensive. This lends itself naturally to cabinet style construction. However, the weakness of the cabinet style are the many parallel surfaces which allow standing waves to form, causing distortion. Designers use techniques to compensate for this problem but it involves adding more passive components to the signal path further degrading the quality.
After hearing this, we had an idea inspired by our friends at Renovo Bicycles, builders of incredible wooden bikes using CNC technology. Their painstaking process involves machining two halves of the frame separately, carving out the inside and outsides of their tubes and then gluing the two halves together to create a full, hollow tube. Using this technique, you can build complex three-dimensional shapes and undercuts that are otherwise impossible.
KEN TOMITA: Years ago I had seen the incredible craftsmanship behind Renovo’s cycles and had a feeling that it could be applicable to our scale somewhere down the road.
With this technique in mind, Joey excitedly went back to the drawing board. He set out to design something that other companies could not build that took advantage of Grovemade’s unique abilities in advanced wood manufacturing.
Rather than a traditional bass reflex design, Joey came back to us with a back-loaded horn design which we would CNC machine out of thick blocks of solid wood. In this design, the lower frequencies are reinforced and directed out of the horn, and the high and mid frequencies come straight out of the driver, which removes the need for Digital Signal Processing. With the extraneous removed, the speaker would create clear, crisp sound, handling the most subtle details with ease.
A: The full-range driver reproduces the entire range of frequency information, enabling total phase coherency for a true point source.
B: The CNC machined enclosure has no parallel walls and no flat surfaces. Like a concert hall or recording studio, its internal geometry eliminates standing waves that cause distortion and time smearing. This is particularly important because the driver's extremely thin metal diaphragm, which is necessary for its performance, would otherwise let these standing waves and reflections reach the listener.
C: The back-loaded horn couples the driver's back wave with the air at the lower frequencies, reinforcing the speaker's bass response.
The stand and speaker grill were then developed over many iterations in order to enable the speaker to float, and give us complete freedom to develop the best form for the job. We then refined the form of the wood speaker body itself. Joey would send us something in CAD for us to critique, and we’d send him something back in crude, hand made foam or MDF models.
The first day we made full size prototypes out of real wood was very exciting; We all gathered around as it came off of our mill. The wood grain looked amazing on the organic curves, and the inside of the horn looked much better than in computer renderings. As we assembled it we got the idea to intentionally leave the machining marks on the inside of the horn.
SEAN KELLY: Showing the process of manufacturing rather than hiding it turned out to be one of our favorite design details.
With our first functional unit, we evaluated the speaker using audio testing tools, and also by simply taking it home and listening to it extensively, comparing the audio to other speakers we liked. Different music genres were tested, with feedback logged for the next round of tweaks. The mid-range (e.g. acoustic guitar and vocals) sounded amazing, but lower frequencies felt underwhelming. Joey went back to work optimizing the acoustics.
JOEY ROTH: I adjusted the internal geometry to reinforce the bass response while being careful not to sacrifice clarity in the midrange and highs.
Through rounds of adjustments, testing and refinement we had fully functional prototypes. Next, we’d have to actually make the speakers at a production level, but that’s a story for another day.
Overall, the design process lasted about a year from beginning to end. Combining forces with Joey Roth enabled us to create an amazing system beyond what either of us could have done on our own. Stretching beyond our individual potential by working as a team was invigorating. Where can we go next?