The Boominator - another stab at the ultimate party machine

I know it won't affect battery time that much but you'd really have to be blind in the first place, and have become deaf by listening to it too long, not to notice where my boombox is even in almost zero-light conditions.

It's not that I'm against it really, and I have considered it carefully. I just don't see the need for it that much. One could always use the 12V power out to create external LED effects.

I totally love neon and LED effects in computer case modding, and use it alot myself for that purpose but for my no-nonsense boombox, I'd forego it. But as I said, if someone wants it, hell yeah, then I could go all out.
 
Saturnus: I'm looking at various driver options, and would it be possible to mount 2 instead of 4 bass drivers back to back?

Would it still give a 360 sound? I'll be going mono for bass, and only using stereo for the mid/tweeter. :)

I'm planning on using these drivers for the bass:

http://www.mcminone.com/product.asp?product_id=55-2421&catalog_name=MCMProducts

but the only problem is that they are a little heavy (4kg each). I'll probably go for a vented box.

These also look nice tho, and I may go for 4 of these:

http://www.mcminone.com/product.asp?product_id=55-1862&catalog_name=MCMProducts

Also they are 8 ohm, so I can wire them in parallel, and still have to channels free for the tweets.

Ifound found a 41hz AMP9 powers these really well when it's fed with ~24v. :)
 
Hi Mike,

The bass drivers you are looking at are not very high efficiency. If you want to extend your play time on batteries you might want to look at something more efficient and sacrifice a bit of bass end performance.

The Celestion TF0818 or someting like it would give you much more output for each watt. It is 94dB sensitivity vrs 87dB for the 8 inch you are looking at. Each 3dB of extra output you double the power required. So for the same sound level 1W on the TF0818 would require a bit over 4W on the 87dB efficient speaker.

However you will trade off alot of bass extension for that extra sensitivity. So it depends on if you want long play time or deep bass.

With the amps you are looking at I don't think you will have a volume problem but obviously the more sensitive speaker will also play louder before the amp clips.

Regards,
Andrew
 
Hey, that looks familiar.
I rescued this one from the rubbish tip in about 1992.
Mine has flashing lamps in the middle of the drivers and a row of LEDS in a sort of VU meter above them.
Yes, that is a Marconi helpdesk sticker on it.
 

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Nice design Saturnus. Have you completed your second version? I'm particularly interested in the solar/battery power source. Which ones will you be using?

About the lights, there was a good point made earlier about someone possibly tripping over it when used around a campsite. As this would be my my intention, and I have friends who tend to drink heavily when camping, someone not seeing or realizing where the sound-box is can certainly happen, particularly later in the evening when everyone is getting a bit drunk.

An easy, low power solution may be to mount an LED or two on each top corner of the box. This would conserve energy used and if you make 'em switchable (on/off), even better. The whole LED add-on circuitry can be added for less than $10, and it provides a nice feature for those of us who need something to "mark out" where the sound box is located so we can hopefully stagger around it.
 
Further to my last post:
I mean't Saturnus parallels one Amp6 Basic into two 8ohm woofers giving good volume and good battery life.
What if I used two Amp6 Basics and drove each 4ohm woofer/tweeter with one output channel?
Will this alter the sensitivity benefits of the magnet to magnet bipole setup?
I don't understand enough about bipole speakers.
Thanks for any replies.
 
When you ghetto blaster lovers arrive at the point where you want extreme audio quality, along with extreme blast and extreme cool, please come join us over on the rejuvenated EnABL for listening thread. We can whip up some virtual patterns for you and add rockets to your pockets, for neighborhood blasting.

http://www.diyaudio.com/forums/showthread.php?s=&postid=1460193#post1460193

Or just have Saturnus drag you over. Long ago lost track of how many blasters have been treated, with just their original drivers left in place. What I see here is going to be a new art form, for sure.

Bud
 
Help me, great master of the Boominator!

Hey Saturnus
Partly inspired by your Boominator I'm now in the process of making my own portable version. I have an Amp6 Basic, and now i need the rest:). I sounds like you know a lot about this amp and about making speakers that has to play outside so I hope you will help me out a bit? I want a light and portable version and since this is my first venture into the world of electronics it has to be relatively simple. I thougt about using one of the HP10W's you used or maybe two 6,5" parallelled into 4 ohms, and then a piezo tweeter for each side. It needs to be as small and light as possible but with as good a bassresponse and high levels as possible. Of course this will be a compromise, so i hope you can tell me how to get the best of both worlds.
I'm thinking about using one 12 volt sla battery and no solarcells at this point.

Best regards
Morten

(I tried to send you an email but since I'm a new user I'm not allowed to do that yet)
 
Storbyblues, as long as you don't exploit commercially but build one for your own use, I neither can nor will stop you. :)

My budget was just over DKK 8000 but I build two at the same time, so without the discounts I got at various places, I figure you should estimate around DKK 4500 for one. Yes, it's extremely pricy, and keep in mind that's still only if you have access to CNC routers and other tools. If you have to have the parts of it made by a work shop, like the two fronts. It'll be much much more.

I do have an older version lying around I'm interested in selling, so mail me if you're interested.

MortenJ, there's no reason the principle can't scale up or down to fit other sized drivers. I would keep the main aspects of it. Those being; drivers mounted on both sides and drivers mounted magnet to magnet internally. Also making the reflex ports double as carrying handles I personally think is pretty genius.

Back to the question. I'd use 2 6½" drivers instead of 1 10" per side to get the impedance down to 4 Ohms, otherwise the amp6basic isn't quite powerful enough for outdoor use. As you can probably tell I used every trick in the book, and also a few of my own invention to get the Boominator as light and compact as possible. If you're using 10" drivers, it can't get any smaller. With 6½2 driver you can probably reduce the size quite a bit.

Email for you both: jaggemam AT hotmail DOT com
 
good to see this thread still going on. summers coming :)

oh yeah, Saturnus, if you wanted to reduce shipping weight, you could always gets customers to buy the battery themselves.

heres my low-brow blaster

http://i31.tinypic.com/2q00ysl.jpg

http://i25.tinypic.com/wr17ax.jpg

been workin on this the last few days. Im going to build one from scratch, but ive got exams, and when the sun appeared last week i said id better throw something together fast.

I put two ciare ch250 drivers into it, and built enclosures for them. at a rough guess theyre about 20lt's each, and theyre not particularly well sealed, deliberately. (Im cheekily calling them aperiodic. :D) i did a lot of reenforcement to the frame, Ive still a bit more to go, but it sounds good, and theres a fair whack from it using an amp32. Even bass, which i was pleased by. The only thing is, im getting what i think is called resonance, or colouration, from the plastic. any suggestion about this?
 
Yeah, that was the general idea with using those standard size SLAs. They can be bought anywhere, so no need to ship them with the boombox. People can just buy their own.

Regrettably I will not be making a new version this year, only minor improvements. And it's generally difficult to make improvements on the design as it is without the cost becoming prohibative for a commercial product which is my goal.
 
NED 209 said:
good to see this thread still going on. summers coming :)

oh yeah, Saturnus, if you wanted to reduce shipping weight, you could always gets customers to buy the battery themselves.

I agree, was my initial thought also...

The only thing is, im getting what i think is called resonance, or colouration, from the plastic. any suggestion about this?

That's what you get with plastic unfortunately... You can minimize it by spraying the inside of the cabinet with some glue to make it thicker and more able to contain the vibreations. Exactly what kind of glue to your need is tough to say, but you probably need a lot. I did this to an old cheap stereo for a relative who was complaining about a rattle a while ago, and it worked just great.

But of course, it's always more fun to be able to push all the buttons - even though they dont do much.


Saturnus> what is the specs for the one you're selling? It's minijack input, right? Cause anyhow I'll be looking into getting CD support for people to bring mix CDs in multiple copys instead of expensive mp3 players.

Love this thread... Just what diy-audio is all about!
 
Pillah said:
Saturnus> what is the specs for the one you're selling? It's minijack input, right? Cause anyhow I'll be looking into getting CD support for people to bring mix CDs in multiple copys instead of expensive mp3 players.

It's the same drivers and the amp I originally had in was a modded T-amp in it but that died so I replaced it with the much more robust amp6basic. Yes, the input is just a headphone minijack and is not equipped with a volume control or any other electronics.

Actually truely orginally it was the designed for a car headunit but that simply uses way too much power to be workable.

It's 10cm longer though and so the dimensions are 100x30x30cm. The center battery/electronics compartment is thus wider and accept standard car batteries up to 25x18cm in size. With a 55Ah car battery it can run about 110 hours before needing a recharge (at constant maximum volume).

Unlike the the current version there's no built in charger or solar cells.

The main differences however is: a different box tuning based on a Qt of 1.2 and not the current Qt of 1.1, cheaper piezo tweeters that are harsher in sound than the current ones, and finally it uses spruce plywood instead of birch plywood which makes the box almost 5kgs heavier without the battery.
 
Cheaper Solar Cells

Nice Boominator Saturnus, thanks for sharing the design info.

I'm contemplating making one myself, but the solar cells you mentioned are quite expensive. Some much cheaper cells can be found at Goldmine Electronics (http://www.goldmine-elec-products.com/prodinfo.asp?number=G4560) that produce 9V@140ma for $8 US (9V@70mA x 2 per package). Add a couple in series and you end up with slightly more energy for about $32 US (8 cells total, 18V@280mA=5.04 Watts), which is quite a bit less expensive than SiliconSolar from what I see on their website. A little more time intensive mounting and soldering the connections, but this is DIY, right?