Today I attended a workshop on acrylic speaker amps, a collaboration of Fostex x DMM.make AKIBA x Otome Dengei Club, which I was looking forward to. It was very good!
As I mentioned in my previous note, I decided to close the earphone EEG service for now, and by a strange coincidence, I decided to start a speaker business for the hearing impaired in January this year, so this workshop came at the right time when I wanted to deepen my understanding around speakers.
EEG] From the Conception to the Closing of an Earphone-type EEG Measurement Device
Although the workshop was 5 hours long (13:00-18:00), the time passed quickly, perhaps because it was a hands-on, work-based workshop.
Instead of building a speaker out of the blue, there was a detailed lecture on the mechanism of a speaker at the beginning, and we were able to see the actual parts disassembled and assembled, which deepened our understanding of the speaker.
For this project, the Fostex division of Foster, a major speaker unit manufacturer, is helping us assemble the speakers from Fostex speaker components.
From left to right
-Magnetic Circuit + Frame
-Film
-Voice coil + Damper
-Diaphragm
-Center Cap
A speaker is a mechanism in which electricity is applied to a coil + magnet, the vibration is transmitted to a vibrating plate, and the air is shaken to produce sound.
You can see that the center of the black sheet is thin and white. This is the magnetic field. I was surprised because I had never imagined that I could visualize the magnetic field! It is exciting to be able to see it!
In addition, he experimented and experienced Fleming’s left-hand rule, which is the part of the coil plus magnet that conducts electricity and exerts a force against the diaphragm.
When current is applied to the voice coil, an upward force is exerted and the voice coil pops out. In fact, when I connected a dry cell battery, the coil popped out, which surprised me as well.
After getting to know the components of the speaker, it is assembled with glue.
In addition, the diaphragm and center cap are attached, and the tinsel wires are formed to complete the speaker unit!
Since I usually buy speaker units only as finished products (and I don’t think I have many opportunities to buy individual speaker units in the first place), it was a great learning experience for me to know the inner structure of the speaker units.
The next step is to attach the speaker to the acrylic plate.
First, we used a laser cutter to cut out the acrylic plate.
Just yesterday, I took a laser cutting license training at DMM.make AKIBA, and I was amazed at the speed of laser cutting.
Mounting the acrylic plate on the speaker.
I like the feeling of gradual finishing.
And here is the finished product!
The picture was taken a bit inappropriately, but it looks much cooler in person.
Next, create an amplifier and actually connect it to the speakers.
Will it make sound? Would it work? It was a very close call, but the sound came out without a hitch! And the sound quality is good!
The original speaker units have good performance, so the sound is probably strong even though the enclosure is small.
When we experimented by changing the amplifier to a high-performance one, the sound quality improved even more, which was immediately apparent upon listening.
The workshop was a hybrid of classroom lecture and hands-on practice, with a classroom lecture on the principles of speakers and then the actual assembly of the speakers, so it was very informative and most enjoyable!
I was concerned that 11,000 yen for two high-performance speaker units, including the amplifier and workshop fee, might be too cheap.
I am sure I will be able to use this study in the speaker projects I do in the future.
We would like to thank Fostex × DMM.make AKIBA × Otome Dengei Club for organizing this long workshop despite the holiday.
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