Low cost project for nephews

You're posting in the wrong section

hi, welcome to avs diy, you are in the right section.

at that age, they are going to want something that makes as much noise per dollar as possible.

for the "mains" i would take a look at a full range driver, something like you might find in a bose cube, that has a "reasonable" frequency response and just run them with no crossover or anything off of whatever stereo set they have. you could probably just find a used stereo system with cheap speakers for the same money and less work to be honest though.

to make the system special, build a single fold tapped horn. this will "blast" bass and truly make the system something that you can't buy in a store for anywhere near the money. for a teenager, big bass adds more fun factor to a system then any other upgrade.

a single fold tapped horn is a very easy build and doesn't require either an expensive driver or amp. when they fire it up, it will make them laugh out loud and next thing all their friends will be building tapped horns. :-)

this is an example to give you an idea of what this is.

http://www.cowanaudio.com/images/th35dwg.gif

several folks here are familiar with the drivers that give a great bang for the buck in a tapped horn application. the only other thing that you will need is a low powered amplifier with the appropriate connections to whatever source you intend to use.

there are some more pictures here (scroll down):

http://www.cowanaudio.com/th.html

the larger the enclosure, the lower and louder the unit will play. as you ask questions, shoot for something with about a 35-40hz "corner".

this is a great project to teach your nephews all kinds of lessons, particularly about safety as well as the extra satisfaction that comes with building something.

good luck with the project and i'll try to help as much as possible.

what do they have now?

Speaker building (especially budget speaker building) isn't a very popular topic on this forum unfortunately. You may have better luck at Tech talk forums over at parts express. I'd specifically look up user Johnny Richards as I believe he's done several super budget builds (your budget would fall into this category ):

http://techtalk.parts-express.com/forumdisplay.php?f=2

Look here.

There is some discussion here.

Hope this helps.

"they have nothing. maybe a pair of small speakers for their computer, and they play video games on a flat panel."

ok. i'll try to whip something up.

the calculations need checking, but i have checked them a couple of times and they seem right.

here is a $30 driver to use:
http://www.parts-express.com/pe/show...number=295-484

spec sheet:
http://www.parts-express.com/pdf/295-484s.pdf

plan is attached. the picture is not to scale, but the numerical dimensions are accurate.

this horn has a corner around 30hz, so even some relatively deep movie notes will blast through.

sensitivity is very high at about 93db 1w1m through the bass region. that is about 6db more than the driver in a ported enclosure (i.e. you would need 4x the drivers in a ported cab for the same sensitivity).

the cabinet has simple ~12" x ~12" external dimensions and is a little over six feet long. it can be stood in the corner or placed along a wall horizontally.

even a 100 watt amp will be sufficient for this "little giant". placed in a corner, it should hit full reference spl (>115db) for most of the bass, which will be completely "awesome" for your nephews.

3/4" plywood would be preferred (make sure to add a hair to the external dimensions if you go this route), but 1/2 will work if you put a little brace or two in there in order to keep the front and back panels from resonating.

i want to see some pics of these guys building this thing and their reaction when they fire it up!

edit: you will need a low cost plate amplifier, but i'm not sure what the best buys are currently. parts express has plate amps as low as $35. i had no idea that they come that cheap. for example: http://www.parts-express.com/pe/show...number=300-782

 

NephewTappedHornBuild.pdf 111.0732421875k . file

Erich is selling the Overnight Sensations for $64 each including shipping. They get geat reviews. They would be a great place to start for your nephews.

http://www.diysoundgroup.com/template/speaker-kits.html

That's awesome that LTD02 put together a horn design for you. It's a monster tho - by "normal" people standards i mean Very curious to see if your nephews decide to take it on.

That's a great thread that PassingInterest linked to with the budget kits.

I was asking about a simple small build plan recently so i looked through some of the research i did.... just about everything was out of your budget range. However, i stumbled on this 2-way kit from Madisound that is on sale for $95

http://www.madisoundspeakerstore.com...er-parts-only/

I'm not familiar with the design itself but i believe it uses the same Vifa tweeter my home theatre speakers use with pretty good results.

Not sure if you're accounting for wood/glue/screws and tools in your budget. Those expenses can sneak up on you. And as far as driving the speakers you need some sort of receiver or amp if you don't already have one.

Keep us posted about what you/they decide.

Good luck,
Joe

These use fairly inexpensive drivers:
http://zaphaudio.com/ZMV5.html

Although madisound jacked up the price of the tweeters quite a bit.

"I hope you are not upset with me"

not at all. 'twas a great idea for a build.

"Why can't I just go buy one?"

because when you mix your labor into a product it takes on a higher level of significance. in the same way that climbing a mountain would not be the same if you got a taxi-cab to the top.