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Multi-Way Conventional loudspeakers with crossovers

Project Ryu - DIY Field Coil Loudspeaker
Project Ryu - DIY Field Coil Loudspeaker
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Old 20th September 2018, 06:16 AM   #711
gomper is offline gomper  United States
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Well, I suppose I've really done it.... I quit my well-paying job as a software engineer a few months ago to devote a couple of years of my life to my creative fascination with this project. I couldn't be happy mass producing a driver or loudspeaker, but I certainly could be producing compelling artworks built around a great driver of my own making. So, that's my plan at present. I aim for either wild success, or as beautiful a failure as I can manage... that seems reasonable.

Lots of posts soon to come - the cabinets are well under way and this driver measures very well.

Click the image to open in full size.

Last edited by gomper; 20th September 2018 at 06:44 AM.
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Old 20th September 2018, 06:21 AM   #712
Norelco is offline Norelco  Philippines
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Wow very nice, Iím sure it sounds good too..congrats! are you accepting orders? Project Ryu - DIY Field Coil Loudspeaker Project Ryu - DIY Field Coil Loudspeaker Project Ryu - DIY Field Coil Loudspeaker
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Old 20th September 2018, 03:53 PM   #713
FieldCoil Adventure is offline FieldCoil Adventure
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Dear Gomper,
Long time to see you again. Very nice , I think you have spent much more time to do and design the nice work.
Can you tell more the sound ?
Thank you
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Old 20th September 2018, 04:00 PM   #714
Destroyer OS is offline Destroyer OS  United States
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Project Ryu - DIY Field Coil Loudspeaker
Quote:
Originally Posted by FieldCoil Adventure View Post
Dear Gomper,
Long time to see you again. Very nice , I think you have spent much more time to do and design the nice work.
Can you tell more the sound ?
Thank you
Tell us everything.
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Old 22nd September 2018, 07:34 AM   #715
Hentai is offline Hentai  Japan
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Wow, good luck in your venture.

Is that chrome on the motor?
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Old 23rd September 2018, 01:03 AM   #716
ghpicard is offline ghpicard  Argentina
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Location: Buenos Aires
Beautiful driver, Gomper!
Keep us posted, please!
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Old 27th September 2018, 06:51 AM   #717
gomper is offline gomper  United States
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Default Driver, V2

Where to start?

Well, after discovering that a guy with an art degree and obsessive personality traits could (with the tailwind of the vast internet at his back and excellent individuals such as yourselves) both design and build a great sounding driver, I decided that instead of finishing the prototype off with a cabinet I wanted to redesign for something a bit more serious, and mindful of things I didn't like about the first version.

Many weeks were spent in Fusion 360... with the guidance of my spiritual adviser, Leonard the Cat.

Click the image to open in full size.

There were key things to address in the new design. First, the prototype ran pretty hot - technically safe, but too hot to feel comfortable selling it to anyone in a cabinet. I wanted a motor with lower resistance, at least 1.5T of flux in the gap, +/-3mm Xmax or better, and that could be perform well with a 12V power supply and remain comparatively cool. That ended up as this, shown in FEMM:

Click the image to open in full size.

Fantastic. Next, while a wooden frame sounds fun and interesting, it definitely isn't as stiff and dependable as a metal frame, and contributes nothing to wicking heat away from the motor. I wanted to design an aluminum frame this time that acts like a heatsink, attached the length of the motor along with a little thermal paste and with a lot of surface area exposed to the air. Eventually, the motors came back from the mill and the frame aluminum and brass elements from waterjet cutting:

Click the image to open in full size.

Hentai, I'm glad you asked about chrome on the motors. A more learned man would have gladly paid the $250 or so for the mill to include plating, but instead all of the metal you see in the new driver is hand sanded and hand polished, by me, to a mirror finish. I won't be doing that nonsense again, should I earn the right to order the next batch of steel... it'll come to my doorstep already plated and polished. Kidding aside, I'm getting a cortisone shot in my wrist tomorrow to fix the wear caused by the collective effort over the past several months...

The spider... keantoken, you were right about silk not being a good choice. Over time and a lot of use, the silk slowly got... very, very tired. Yeah, it started to simply sag - and as we speak the voice coils in the prototype are sitting way too low in the gap. I loved the softness of the suspension in the first version however, and the wide footprint. 3D printing was the best compromise... I decided to make the spider in two parts - a hard, lightweight carbon fiber collar and an industrial strength, flexible TPU attaching the collar to the frame arms. It weighs about a gram:

Click the image to open in full size.

Next, the cones and surrounds. In the first version I made the mold forms myself from plaster, but having added a 3D printer to my tool set I just printed, sanded and sealed perfectly symmetrical mold forms for the whizzers, and two-part molds for the main cones and surrounds for easy removal of the main cone (the pictured mold comes apart at the surround ring):

Click the image to open in full size.

I eventually found a higher quality hosho paper to work with as well, and now the main cone, whizzer and voice coil former are all hosho washi. I absolutely love the natural, detailed sound they produce. Here's some of that, a voice coil and wet cones drying on the molds:

Click the image to open in full size.

Click the image to open in full size.

I'm still using the same wonderfully light and thin lambskin leather for the surrounds - I can't imagine ever wanting to try something else.

Okay, it's late here and I'll wrap this up as a first installment. Tomorrow, I hope to share and discuss the measurements from the driver, and talk about the cabinet design. Everything I've done so far spells a very low Qts... all else about the T/S params is ideal for me, but I don't really want that - I want a nice, easy to build bass reflex design, and a loudspeaker that will play +/- 3dB to 40Hz. I am led to believe that I can achieve that, and the Xmax and low mass I want with the addition of a simple series resistor to increase Qes... and in testing that does appear to be the case. More tomorrow.

Last edited by gomper; 27th September 2018 at 07:11 AM.
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Old 28th September 2018, 11:37 PM   #718
fabel is offline fabel  Germany
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Booarr gomper - stunning beautiful ... i hope deeply they will sound as breathtaking as they look

G F
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Old 29th September 2018, 12:08 AM   #719
gomper is offline gomper  United States
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Thank you so much, guys! I’m working up another long post and additional pics, along with t/s params and more details, questions - we’re flying all day, but I’ll see if I can’t get it up here before we lose WiFi on the flight... Hopefully you’ll all like the cabinets as well, they’re a pretty bold design that exposes the driver to view - glass, santos mahogany, brass, aluminum and black granite...
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Old 29th September 2018, 04:23 AM   #720
bvtrinh is offline bvtrinh  United States
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Hello Gomper,

Iím not sure if itís premature to ask but what is the size of this beautiful driver and cost?

Bao
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