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REFLEX SPEAKER SYSTEM UL Lafayette Industrial Design - Fall 2010


Project Brief The first project given to the class in the fall of 2010 was a relatively simple one: design and build a pair of working speakers that could be used for anything. This was less of a project about marketing and more of a personal preference endeavor, but

the clever thing about it was that it was also an exercise in designing around components. Each student recycled a speaker set and used the parts to make a set of custom speakers, which were all guided by different concepts based on what the different parts required and what they could do.


Asessing the Problem The project started by first finding a pair of speakers that could be disassembled and recycled. A small pair was found in a thrift shop [Fig. 1] and were in relatively good condition, but had performance problems that desperately needed to be assessed and fixed. The shape of the housings resulted in a tone lacking crispness and warmth, causing the sound to be very “boxy” [Fig. 2]. There were also volume issues with the set. When the volume knob was cranked up, the sound was still lacking the punch necessary to be reasonably audible, so the only way to raise it more was to increase the volume from the sound source itself (computer, phone, etc.), but doing so would result in high amounts of distortion. Since this project required that the electrical components stay relatively untouched, it became clear that the only real option was to redesign the speaker housing in order to “fill” in the sound’s tone gaps and fix the distortion.

Fig. 1

Tone Curve

Bass

Fig. 2

Mid

Treble


Types of enclosures

Bass Reflex

Fig. 4 Fig. 3

Basics of Sound Physics Since this project required acoustic shaping, basic knowledge of sound science was a necessity. The phenomenon of sound is a relatively simple concept. There’s a source point (in this case a speaker) of the sound, and then a medium in which it travels through (the air in most cases). When the source vibrates, it causes whatever medium its in to vibrate as well. This is actually a form of what’s called a compressive wave, because the molecules in the medium

literally compress (compression [Fig. 3]) and decompress (rarefaction [Fig. 4]) against each other to transfer the source’s vibrations. When the source vibrates, it causes whatever medium its in to vibrate as well. Another important thing to note is that sound travels in all directions, although the energy dispersed in all of these directions is usually stronger in one or two directions, depending on the configuration.

Dipole Passive

Sealed


1. Ideation

2. Testing

In the ideation phase, the focus was to come up with some interesting ways of morphing the speaker’s tone without making changes to the circuitry. Many different casing shapes were explored, most of them rather unorthodox in function, and were aimed to be decorative since the speakers themselves would mostly be staying in one spot, like a piece of furniture. Sound reflection was a prominent theme among these designs, so they were then tested to see what the effects would be.

The testing was done by removing one speaker from its housing and molding sheets of paper and plastic around as music was played. Most of the concepts in the ideation phase proved to be much less beneficial than expected, so a few more experiments were performed that were different from the original drawings. What did end up working was a lexan plate cut to fit the speaker in the middle of it. The treble and bass tones were much more pronounced, and the overall volume was better, so this model went through further development.

Development


3. Revisit

4. 3D Development

Quick gestural drawings were made to get a rough idea on how to apply some styling to this newly discovered plate model. The original idea was to make it look like the object was standing up and talking to the user as he/she listened to it, giving it a bit of life instead of it being completely passive. However, this idea was not solidified, because the components themselves, once incorporated into the design, had a massive effect on the product’s size and gesture.

It was decided that the final form should be developed in Rhino 3D to see if the previous gesture drawings would prove to have the desired effect and maintain a size that wasn’t too obtrusive. The final design used four small legs to stand up instead of one big one because of the stability and size. A physical working model of this design was also made out of wood and stained red to match the desk it would be staying on. It was also used as a set prop in the movie “Looper” starring Bruce Willis.


Final Product After around 6 weeks of development, the speaker project ended, and Reflex was complete. The project got a face lift during the summer of 2010 to look more like a high-end product someone could buy off the shelf and to improve the plausibility of manufacturing. Reflex was originally supposed to be constructed

out of wood, but the exterior parts were changed to plastic so they could be molded instead of milled, reducing production cost. This change paired up with Reflex’s simple assembly could also allow consumers to easily take the speakers apart and repair or customize them without damaging any of the components.


How It Works The two acrylic discs that reside in front of the speakers defines Reflex’s function. By adding these discs, energy that is lost vibrating the air around the speaker body is instead blockaded and forced to reflect itself back to the

listener. This boosts volume and helps fill in the tone by better amplifying the high frequencies that used to get lost in the old speaker housing. To help clarify the sound even more, a hole was opened in the back of the system so the speaker

itself could vibrate more freely, thus adding more volume to the sound. It also allows the speaker’s backwards compressions to be used in the mix, adding a little extra bass to the overall tone.


Audio Source

Open Back

USB Power

RCA connectivity


Trey Petitjean I n d u s t r i a l

D e s i g n e r

Reflex  
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