Something never seen before (I think)...

[BrianG]

Before I get into this, I want to say that this is NOT a serious project by any means. It was just one of those whimsical things that grab me from time to time.

A while back, I was driving my Revo around the yard while listening to headphones when a car went by with a booming stereo. So, I figured: Why not install a stereo in the Revo? An idea was born.



And just in case you think you didn't read that right: Yes, a stereo in a Revo.



First, I started by tearing apart a set of old computer speakers that had a blown internal amplifier. So, now I had a 2.5" full-range driver. Not exactly deep bass material, but whatever.

Since the Revo doesn't have much room on the inside, I thought I'd make a speaker box that would sit in the rear "bed". After making a few measurements and a trip to Lowes for fiberglass resin and some thin wooden dowels, and a trip to Wal-Mart for some fleece, I started assembling the box. The pics below show some of the various stages of the fabrication.


The wooden frame made of 1/4" square dowels with fleece wrapped around it:



Several layers of fiberglass inside and out and a bit of sanding:



Test fitting the driver. Perfect fit!



After a little textured paint (to emulate speaker carpeting), a speaker gasket, and some port tubes:



I didn't have any Theille-Small parameters for the driver, but I figured I'd make the box as big as I could and then port it for a little extra 100Hz response. The result was adequate at best. Oh well. Can't make a hi-fi out of junk I guess.

So, now I need a car amp.... but to scale. So, an I found a small and cheap 7W mono amp circuit. The amp chip is really designed for low-power car headunits, but an amp is an amp right? The IC will work well from ~8v all the way up to 18v+, but needs at least 14v to get the rated 7W out on a 4ohm load. Easy enough on 14 NiMH cells I think. After some assembly and shoe-horning into a RadioShack enclosure fitted with appropriate connectors:


Internals. Pretty basic stuff. You like the blingy gold heatsink?



The amp all buttoned up:



The amp and "subwoofer" box together for size comparison:



So, a little velcro to hold down the box in the Revo truck bed, a little power wiring to my batteries, and hookup to a tiny flash-based MP3 player is all that is needed to have tunes while zooming around! Please don't mind the poor Crowdpleaser paintjob - artistic flair is not my strong suit!


A last pic showing the box mounted in the truck
:



Yeah, the sound isn't the best, but is surprisingly loud when running around. Of course, you wouldn't want to race or bash with this stuff on there, but it was a fun project nonetheless. :)

Maybe with a nicely painted hummer body, a true stereo would be an interesting project. Maybe even have a true subwoofer. :)

[jnev]

I have got to hand it to you, that that thing is sweet!!! I didn't think that it would fit in the bed that well, but it doesn't look like it doesn't belong there. You seem to be the first to try so many different things.

You wouldn't happen to have a movie of the revo driving witht he music on,. would you?

Awesome job again.

[BrianG]

Thanks! Mainly, it was a combo of me being bored and looking for a project while waiting for my next conversion. :)

No, no video.... yet. I may snap a quick one sometime.

[jnev]

Man Brian, how can you mock us like that... telling us about a new conversion, but not telling us what it is? Shame... :)

Maybe a hint? :027:

[bdebde]

Someone has WAAYY too much time on their hands!!lol Nice job too though, (i am also a car stereo nut).

[BrianG]

RC: Actually, I had done this before I got the CRT.5. So that was my next conversion, and it still isn't truly done since I'm now waiting for a spur...

bdebde: lol, tell me about it! Boredom is a bad thing. My actual 1:1 vehicle stereo sounds a "tad" better.

[Gustav]

Man that is dope! Now you just need to record the sound of a nitro engine and play that through it.oh no,hang on..:007:

[BrianG]

Well, since nitro sounds like a loud mosquito, I'll just take some recordings of my backyard tonight and boost the volume. :)

[hyperasus]

lol. That's gotta hurt battery runtimes.

[Procharged5.0]

Brian,

You are a trip! I was in tears reading this thread! You are a genius. Whacked, but a genius!

Excellent work! I loved it!

I'm a pro-audio & video engineer by trade so I totally appreciated this "whimsical field trip".

Thanks for making me smile & laugh this morning!!!!!

[Procharged5.0]

Brian,

Heres a crazy though t for you.

How about a nitro "noise cancellation system'????

Add a mic & signal inverter and perhaps you'll have the first silent nitro truck!!!!!

(p.s. don't forget to credit me for the inspiration!!! LOL!)

[BrianG]

Well, 7w is only 0.5A at 14v, but you NEVER see that kind of average current draw unless playing a non-varying sine wave. Average output is more like 2-3w. At any rate, I won't be running it in a race so it hardly matters. May make a shelf queen someday with a real stereo complete with sub. More a conversation piece than anything functional. :)

[BrianG]

Procharged: lol! I think it would take a bit more power than 7w to cancel that noise! Probably be easier to make a true muffler. Or better yet, just keep it BL and have more power and quiet to boot!

[Procharged5.0]

Yes, It would take much more than 7watts! Fun to think about though.

I helped an automaker several years ago design a cancellation system for one of their premier cars.

[BrianG]

That must have been fun to work on! Did the transducer mount inside the exhaust driveline, or near the exhaust opening? If inside, it must take special materials to handle the heat! I imagine the system consisted of a microphone, an amp with phase control, and a special speaker?