What kind of heat gun are you using? Show us a photo as I can't imagine a small shop one being able to handle how big of an area you are softening up. The curves look awesome though - it will be too nice once you paint it with an automotive finish. You will have the same behavior as someone with a shiny new car who refuses to park in a tight lot for fear of door dings. So they either walk real far or they don't drive the car. 🙂
Sure thing.... It's just an el-cheapo heat gun, $20 from Harbor Freight if I remember correctly.
Oh, I know what you mean... I was at the store and stopped to check prices on gym bags to carry it I. When it's done... Just what I need for a " job site radio "... Ha ha ha
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Well, just an update....
The box has been at the painter's for longer than expected, but here's a couple pics he sent me the other day.... Hopefully just a few more days and I can get back to work on it.
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The box has been at the painter's for longer than expected, but here's a couple pics he sent me the other day.... Hopefully just a few more days and I can get back to work on it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
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Well, I finally got to work on the box a little more....
I cut out the end caps and sanded them down to the final shape. About an inch larger than the end of the box. Then glued another piece to it to make the end cap 1 inch thick.
I cut out the end caps and sanded them down to the final shape. About an inch larger than the end of the box. Then glued another piece to it to make the end cap 1 inch thick.
Next I routed a 45 degree chamfer around the end cap, and routed out the port opening to create a flared end. Now it's really starting to take shape!
I cut the grill down to length... Now I just need to glue up the other end.
I am thinking about drilling a 3 inch hole in the middle of the ends ( the ends will be plastic dipped black ) to let the orange box show through.
An externally hosted image should be here but it was not working when we last tested it.
I cut the grill down to length... Now I just need to glue up the other end.
An externally hosted image should be here but it was not working when we last tested it.
I am thinking about drilling a 3 inch hole in the middle of the ends ( the ends will be plastic dipped black ) to let the orange box show through.
Well, woodwork is done....
I decided the ends were a little dull, so I cut a hole in the middle to let the orange peek through....
An externally hosted image should be here but it was not working when we last tested it.
I decided the ends were a little dull, so I cut a hole in the middle to let the orange peek through....
An externally hosted image should be here but it was not working when we last tested it.
Well, I finally got around to measuring the drivers in the box....
First here's the impedance curve of all four woofers wired in series-parallel. I had to measure the left and right side at the same time, as the box is only one chamber. If I measured just one side the other two woofers would act like passive radiators.
Pretty much what I was hoping for. Tuned to about 35Hz. Little ripple at about 300Hz, probably some box resonance ( might even be the grill ) but not enough to worry about. Actually its a little smoother than I expected, being a thin plastic tube.
First here's the impedance curve of all four woofers wired in series-parallel. I had to measure the left and right side at the same time, as the box is only one chamber. If I measured just one side the other two woofers would act like passive radiators.
An externally hosted image should be here but it was not working when we last tested it.
Pretty much what I was hoping for. Tuned to about 35Hz. Little ripple at about 300Hz, probably some box resonance ( might even be the grill ) but not enough to worry about. Actually its a little smoother than I expected, being a thin plastic tube.
Next I measured the frequency response of the drivers. I imported that into a crossover design program. I tried a lot of different things with the crossover. After a little playing, I ended up with a simple 2nd order design. Just 4 components.
Tweeter: 7.8uF in series, .47mH in parallel
Woofer: .95mH in series, 50uF in parallel
Here is the modeled response of the crossover...the tweeter looks like it is cut off quite low, but it is actually 15Db down at 1000 Hz. I measured the tweeter from the general listening position, which is about 45° off axis, so the response was just a slope from about 2000Hz on up. The high pass section just levels out the slope, this way I don't need any additional attenuation on the tweeter.
Modeled system response...
And system impedance, should be a pretty easy load for the amp..
Tweeter: 7.8uF in series, .47mH in parallel
Woofer: .95mH in series, 50uF in parallel
Here is the modeled response of the crossover...the tweeter looks like it is cut off quite low, but it is actually 15Db down at 1000 Hz. I measured the tweeter from the general listening position, which is about 45° off axis, so the response was just a slope from about 2000Hz on up. The high pass section just levels out the slope, this way I don't need any additional attenuation on the tweeter.
Modeled system response...
And system impedance, should be a pretty easy load for the amp..
I could post the measured response and impedance ( .frd and .zma files ) of the woofer and tweeter if anyone would like to play around...I'm always open to suggestions. 🙂
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Well, I went ahead and finished up the paint myself... I used Rust-olium cobalt blue metallic paint and finished it up with Crystal clear enamel...
Its not perfect, but came out pretty darn good. No runs! I'm not the best painter, I usually end up with runs ( I must be getting better ). Notice the nifty little stand I made to paint it, they allowed me to rotate the box so I could have easy access to all sides.
After letting it dry for a few days I mounted everything for ( hopefully ) the last time.. Did I mention, this thing is a P.I.T.A. to put together. Here's a peek inside...
You can see pretty much everything here. The notch on the left side supports the rear of the amp. Next to that is the vent opening. At the top is the rear of the tweeter. Woofers on the right, and the screws at the top and bottom hold the handle and foot.
Then, I temporarily set the crossover parts in place to see how much clearance I had ( the amp is wrapped in blue masking tape here )...
I'll post a little more later.
Its not perfect, but came out pretty darn good. No runs! I'm not the best painter, I usually end up with runs ( I must be getting better ). Notice the nifty little stand I made to paint it, they allowed me to rotate the box so I could have easy access to all sides.
After letting it dry for a few days I mounted everything for ( hopefully ) the last time.. Did I mention, this thing is a P.I.T.A. to put together. Here's a peek inside...
You can see pretty much everything here. The notch on the left side supports the rear of the amp. Next to that is the vent opening. At the top is the rear of the tweeter. Woofers on the right, and the screws at the top and bottom hold the handle and foot.
Then, I temporarily set the crossover parts in place to see how much clearance I had ( the amp is wrapped in blue masking tape here )...
I'll post a little more later.
Time to finish everything up.
I need the crossover to be removable, in case I ever need need to remove the drivers. So, I hot glued the crossover to a piece of 1\8 inch hardboard and used Velcro strips to secure that to the box...
Here's the bottom of the crossover board...
Crossover mounted, amp plate painted. Time to close it all up....
Almost done.... I just need to mount the end cap/ grill assembly.
I need the crossover to be removable, in case I ever need need to remove the drivers. So, I hot glued the crossover to a piece of 1\8 inch hardboard and used Velcro strips to secure that to the box...
Here's the bottom of the crossover board...
Crossover mounted, amp plate painted. Time to close it all up....
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Almost done.... I just need to mount the end cap/ grill assembly.
Ha, is anyone even following this thread? 😉
I feel like I'm talking to myself, lol... 🙂
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I feel like I'm talking to myself, lol... 🙂
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I am following. and I sure many others are too.
I'm very impressed with your workmanship.
One thing for sure, you'll not mistake your "work-radio" with anyone else's.
I originally thought the orange color was your finish color and not just your primer coat. I liked it too. The blue color is great.
Joe L.
Definitely following. Was interested in the nd91 for my own project. More in a micro format and battery powered though.
Will be a plain wood box though lol.
Will be a plain wood box though lol.
+1
Orange looked so "bad ***" 🙂
I'm still impressed with shape of the box, didn't know this could be done so simple. Thanks for this idea!
I think I might try and adapt this for motorcycle use.. I am watching this closely. Beautiful job
Oh, good... I'm glad someone's following, LOL.
Yeah, the Orange was supposed to be the finish color, but the guy I paid to paint it kept sanding through the paint and just gave up on it. I wanted something metallic, and the only metallic spray paint I could find on short notice was the blue.
It all worked out though... The blue is a little transparent, so it is bright blue from one angle and dark purple from another... It's pretty cool with all the curves.
Here is the sketch I made before I started...
I'll post the finished speaker tomorrow.
Yeah, the Orange was supposed to be the finish color, but the guy I paid to paint it kept sanding through the paint and just gave up on it. I wanted something metallic, and the only metallic spray paint I could find on short notice was the blue.
It all worked out though... The blue is a little transparent, so it is bright blue from one angle and dark purple from another... It's pretty cool with all the curves.
Here is the sketch I made before I started...
I'll post the finished speaker tomorrow.
I think that the title of the thread is what's holding it back. I was just looking for an update and I bypassed the thread as the title doesn't even hint of the great info here. Pretty bad since I even posted in it.
Yeah, I think your right... I decided to start a new thread now that construction is all finished up. Time to measure and tweak it, so work is still not done... Here's the new thread: http://www.diyaudio.com/forums/mult...tom-molded-pvc-portable-bluetooth-stereo.html
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