Portable active boom box (LiFe, solar, mini DSP)

[m R g S r]

I have a bunch of spare stuff sitting around. I don't know what to do with it.
I already have my larger beach radio, how about a self contained (solar panel separate, will plug in) active pool side radio?

I currently have sitting here:

Mini DSP --would run iPod directly into this. (Use iPod to adjust volume, wouldn't bother with the line out then adding a pot for volume on the mini DSP.....although I could try both and see if the SQ is that much different.)

MB Quart made in Germany PTE 25 tweeter...think it's a titanium dome 1" not sure

Alpine 4ch class D amp. (Alpine Electronics of America, Inc.)

I started dismantling the amp, cuz it's been sitting there. * Might as well make it as light as possible. *

(1) peerless SLS 8" subwoofer
http://www.parts-express.com/pe/showdetl.cfm?partnumber=264-1102

Alpine Type R 6.5" midrange

I know I'd need a LiFe battery of some sort, I was thinking for low(Ish) listening levels, with a 13 watt solar panel, I'd be able to get away with a 5-10 a.h. Battery.
Something like this....$75 or less would be nice
http://www.batteryspace.com/Custom-LFP-12.8v-6.6Ah-Module-w/-PCB-and-6-18Awg-Open-Wires.aspx
$55 6aH battery here...
http://www.batteryspace.com/custom-...ck-12-8v-6000-mah-77wh-2a-rate-w-pcb-7-2.aspx

This radio will most likely be used poolside only in FL for me and my parents etc when we go to the house down there. So I'd like to keep cost on the low side.

Some fiberglass would be fun to use, post up some ideas!


Just for reference here is my big beach radio. So no need for anything this large lol

An externally hosted image should be here but it was not working when we last tested it.

 

[m R g S r]

I'm returning $60 worth of stuff to P.E....including the celestion 5" speakers, because I found this alpine type R 6.5" that I have, along with the dome tweeter from mb quart

 

[m R g S r]

Nevermind

 

[m R g S r]

External dimensions...

Front and rear panels are 3/4" top bottom sides are 1/2".

Got started clamping. No screws to keep the outside clean looking. (And no need for pocket holes on this cabinet)

The amp will fit as is, but it will be very tight. Esp with the separate sealed enclosure for the 6.5" mid. So I will be modifying (or milling an entire new heat sink) for the amp
I plan to have the end of the port opening right on the Heat sink to help with air exchange inside the hot small enclosure. This amp heats up quickly. (Despite it being class D)

Alpine components probably not worth anywhere near what alpine charges for them :/

Total internal volume before battery displacement, amp displacement, driver displacement and port displacement is 1260in^2. Or 0.73 cubic feet.

Divider centerline for midrange enclosure will be placed 6" from the inside, so the midrange enclosure will be 345in^2 or .2 cubic feet.
And the subwoofer enclosure will be 885in^2 or .512 cubic feet.

 

[m R g S r]

This battery
Custom LFP 18650 Flat Battery Pack: 12.8V 6000 mAh ( 77Wh, 2A rate ) w/PCB (7.2)
Is 5.91"x5.5"x.91". So it will fit inside the midrange enclosure. Not sure if I'm going to mount it in there yet, however.
It would take up 29.57in^2 from the mid enclosure.

 

[m R g S r]

With a 2" port 7" long (0.056 cubic feet displacement), the amp roughly 10"x10"x1" (0.058 cubic feet) and driver displacement, it will be right around .60 cubes of volume left.


That should yield roughly 40hz tuning for the subwoofer. Perfect for rich sounding bass at low listening levels.

Flared port:
http://www.parts-express.com/pe/showdetl.cfm?partnumber=268-348

 

[m R g S r]

Nice bump in the 60-80hz range, and still acceptable bass....

17L enclosure, 2" vent 7" long

and with 20 watts it will do 103db or so....perfect, exactly my goal for this project!

 

[m R g S r]

My solar panel is slightly large for this application, so I'm trying out a different panel....for $25 we'll see what happens.
It's most likely a 5w panel. It says .7A at 12v but I doubt it's that high. Probably 5w.

 

[m R g S r]

Glued another panel on. Gotta start cutting holes, planning all mounting etc of components etc

 

[m R g S r]

It appears I need to use this battery. The other battery had a 2A discharge rate pcb. That won't be enough.
The 7A discharge rate should be fine for when the amp pulls peaks during high bass content music.
Custom LiFePO4 26650 Battery: 12.8V 6.6Ah (84Wh 2A Rate) w/ PCB & 6.0" 22AWG Open Wires
$68 for this battery. But it won't fit in the midrange enclosure, no biggie.

 

[m R g S r]

10W 12V poly solar panel |Eco-worthy
I ordered that panel as well. Will be using this on the top and the smaller one on the back. Should give me roughly 10-12 watts from sun. For most music that should be enough for 40 watts average....

 

[m R g S r]

Divider in place. Most of the parts should be arriving this week or early next week. Should start to move from here forward.

5.615 Liters measured internal volume for the midrange.

 

[m R g S r]

Just messing around to see if the concept will actually work.

You bet it does!

 

[m R g S r]

Got started on hole routing.

 

[m R g S r]

Even without the original heatsink it's still too tight of a fit. So no point in milling a new one, I'll just modify the original.

Unmodified:

Modded to fit:

 

[m R g S r]

Flared 2" port

Getting closer!

An externally hosted image should be here but it was not working when we last tested it.

 

[m R g S r]

With some careful router work I got the tweeter to press in to its cutout like a glove! And no issues with sealing around the tweeter because I didn't break through the 18mm panel.

Layout

 

[m R g S r]

Modified amp heat sink, wood notched to fit the tabs that stick up. Port in place. Coming along!

Making the back removable, hence all the tabs.

 

[m R g S r]

Routed the edges with a 45 and sanded a little.

One of my tabs broke off. Because of the Gap between the back panel and the tabs. I'm going to bolt the box to the mill at my metal shop tomorrow and mill the entire back down .100" or so. It will be perfectly flat then. Back will bolt snug with no problems. And I will add a thin layer of foam tape as a seal between the wood mating surfaces.

 

[m R g S r]

Bolted to the mill this morning

Nice and flat!