Introduction: The Boominator: 360° of 115dB Music

Picture of The Boominator: 360° of 115dB Music

Hi there and welcome to the Boominator Buildlog.

This is the pinnacle of boomboxes that me and my friend have been working on for the last couple of months. Many days were spend building this beast. What makes it so great you may ask. Well, multiple things:

- Capable of doing 115 dB at 1 meter

- Capable of sustaining full output for at least 20 hours.

- 360 degrees of sound

- Excellent bass performance outdoors

- LED strips around the woofers perimeter that flash on the beat

- And many more small things

Building it was almost as fun as seeing and hearing the final product :)

Before we begin the buildlog I want to thank:

-AccuSafe for supplying most of the parts and having awesome customer service

-User Saturnus for doing the audio engineering behind the design

I'll be referencing to pictures with [..]

Step 1: Preparation

Picture of Preparation

Beginning a DIY build without proper preperation is a recipe for disaster. So that's where we start.

In the first picture you can see our cardboard mockup which we used to get a feel of its size and form factor. It measures 90x30x30 (triple cube, 81 liters). Pretty big, but small considering the performance. Essentially its a portable PA setup. The sketchup drawing of the design can be found here: https://3dwarehouse.sketchup.com/model.html?id=ed70429792f0ff9d421ffb972735edc

After placing our online orders we went to the local hardware store to get our 12mm 9ply birch plywood cut [2]. Man that stuff is strong.

A couple of weeks later our orders arrived. The 4 10" P.audio woofers [3+4], battery, PSU, amplifier and battery protection [5], and some general cable stuff.

Step 2: Start of Construction

Picture of Start of Construction

From cardboard to wood. You can definitely see it getting shape now. The Boominator drivers are mounted back to back (bipole), with the magnet against the centre brace. This makes the construction very sturdy. To reduce weight, connect the two chambers and increase total chamber volume the centre brace needs to have holes in it [2] and a cutout for the handle on the side.

The handle doubles as a bassreflex port (the other way around really ;p) so it needs to have a specific size [4], otherwise it'll mess up the tuning. We cut out it using a jigsaw [5]. In picture 6 you see us rounding over the exits to reduce port noise and to get a softer grip.

Then we glued and screwed the side piece and centre brace to the baseplate [7] and repeated it for the other side [8].

Step 3: Circles, Holes and Rounds

Picture of Circles, Holes and Rounds

The router was our best friend at this step. It's very difficult and tiresome to make (good) circles with a jigsaw.

Drawing it out [1], using the router with our DIY circle jig [2], testfitting the woofer and wood with a grill sandwiched inbetween [4].

Time for another mockup [5]. As you can see, this thing is a beast.

In the last two pictures we're trying out our LED strips.

Step 4: Testing and Mounting

Picture of Testing and Mounting

We hooked up the woofers to see if they all worked. Once they're mounted they should last a lifetime. The upside of such a strong construction is that they probably won't be damaged. The downside is that if we manage to get them damaged, swapping it out is next to impossible.

The next picture is of our piezo tweeters. Huh, piezo tweeters? Aren't those that horrible type that sound like plastic? Yup, if you don't know how to use them they are. We filled up the grooves with sealant to prevent resonance [2]. Because piezos are capacitive elements we can use a simple resistor to create a first order RC highpass as crossover; cutting of the first 'plasticy' peak and reducing the power consumption by a small bit. Their natural response is 3.5kHz and up, which is where our woofers start to drop their response. Perfect fit!

In picture 3 the woofer and tweeter are mounted with acrylic sealant, which is drying in picture 4.

Step 5: Prepping Electronics

Picture of Prepping Electronics

While we left the speakers drying we grabbed the soldering iron to prep the electronics.

To save the speakers from unneccesary excursion at frequencies it can't really reproduce we modified the highpass on our high efficiency class-D MaxAmp20 by removing some of the input capacitors.

The amplifier is 90%+ efficient and can output 2x15W in 4 ohms. This doesn't seem like a lot, but this system is so efficient that it puts out 101 decibel with 1 watt at one meter. So if 1W is already very loud, imagine how loud 30W is ;p.

Then we, or my friend really, assembled the AccuSafe [3]. He never soldered a printed circuit board (PCB) before, but it turned out great. The AccuSafe is a PCB with a comparator circuit and a relay onboard that cuts off the power the the electronics at 11.5v to prevent battery damage. It also switches to PSU/charger when available.

The front of our electronics compartiment will be wrapped with carbon. We tested our wrapping skills on a test piece first [4] and then proceeded to our real front piece [5]. From top to bottom: off/led/on, volume knob, 3.5mm input, LED switch, cigarette socket.

The cigarette socket can be used for a USB charger, voltmeter to check battery status or of course a cigarette lighter.

Step 6: Assembly

Picture of Assembly

Now we get to the biggest part: assembly. In picture 1 you can see why it's so strong. It can't flex along any axis.

The grey stuff on the speaker magnet in picture 2 is chemical metal. It is very strong, very stinky and very chemical. As you can see we already wired up the woofers to the tweeters. Later they will be wired in pairs to the terminals you see on picture 3.

Next thing you know: it's assembled. Now it's time to wire it up; the tape over the speaker is to prevent hot solder from dripping on the cone while soldering. The speakers need to be wired in phase: each speaker needs to move towards or away from the center at the same time.

Step 7: Painting and Electronics Compartiment Wiring

Picture of Painting and Electronics Compartiment Wiring

These steps need more pictures than words.

The LED strips still shine bright despite the slightly painted parts. We used Warnex/Duratex, a very durable type of structured paint that's often used with pro-audio gear.

After a bit of testfitting we wired everything up. We used multiple meters of wire ;p. The cutout on the right is to slide over the terminals. It worked out perfectly in the end. The backside with the 230v input, LED strip controller sensitivity knob and name plate on it sealed the compartiment off. It's jammed in there as you can see.

In the last pic we are testing it out, the module is behind it.

Step 8: The Final Product

Picture of The Final Product

Hope you enjoyed the buildlog. Please vote on our project for the DIYaudio2015 contest if you liked it.

If you have any questions/comments don't hesitate to ask

Comments

jneave (author)2015-04-13

Hi,

Saw this on the facebook Instructables page and we've been trying to figure out how to build something like this for a very long time.

So, we're going to build this as a learning experience.

Can we get some more details on the electronics side of it?

Specifically which amplifier boards you used, as well as the lead acid charging board?

Thanks.

lutkeveld (author)jneave2015-04-13

This is a very good beginner project, but be prepared to spend a lot of time on it ;p.

Everything is 12V powered and tied into a central star. The charger is a H-Tronic 800mA from Conrad with stripped cables. Input to the IEC plug on the backside, output to the Accusafe (which couples it to the battery).

There is a lot of flexibility in the electronics side of this build. If you're serious about building one you can shoot me a PM and we can work out a Bill Of Materials based on your preferences. You can also visit the main topic on DIYaudio.com and ask some of your questions there.

jneave (author)lutkeveld2015-05-17

Hi,

Most definitely we're very interested. For years we've been mulling the design for what we've named The Rucksack Rig. But due to lack of experience we've been unwilling to pull the trigger on an untested design with no practical experience.

Sadly I'm pretty damb ill at the moment. Hopefully a few weeks/months I'll see some improvement. No idea how in supposed to pm you. Didnt even get notification about your reply!

Got several interested party people now. Hopefully I'll be better soon and we we can get started. It's much easier to contact me on Google Hangouts of you use it. I'll try to PM my address

lutkeveld (author)jneave2015-05-17

A speaker in a rucksack definitely rucksucks. Time to be blown away by quality construction :) Click my name, somewhere on my profile page should be the private message button.

jneave (author)lutkeveld2015-05-20

The rucksack was just for transport! Also accessories. stage 2 will be one of those quarter wave folded horns called the suitcase sub.

narnbak (author)jneave2016-07-08

We have a rucksack rig in case you're interested :)
http://infaders.com/

thomas2016 (author)2016-03-19

Hi man,

One of these has been on my list for some time now & finally have the funds to get the parts, as you have gone through the pain of finding suppliers in the EU would you help me out with a BOM and where you got them from?

Nice build & writeup

Thanks

Tom

gabrielkyne (author)2016-01-04

Incredible build.. I want to make one but I don't feel like I have the experience. Got any tips for me? What do I need to learn before I can understand how to build this from the info in your guide?

lutkeveld (author)gabrielkyne2016-01-04

Read up on some basic electronics to know what's what so you don't blindly do things. Also read the Boominator thread on DIYaudio.com, it's large but it's worth it. It's full of questions of people like you, make annotations along the way so you can refer to them later. If you don't know certain things you can send me your questions. I can't help you with everything because it's too much. Ask detailed questions and I'll help you further. See it more as a learning project than only doing it for the outcome (a nice speaker). Otherwise you'll get frustrated really fast ;p

gabrielkyne (author)lutkeveld2016-01-05

Hey, that sounds great. I've been wanting to gain that knowledge anyway so this will be a nice start. Do you have some resources you can suggest. A beginners book on electronics maybe?

lutkeveld (author)gabrielkyne2016-01-05

Electronics for dummies is a good place to start. You can also get really far by just doing a case study on every word you don't know. Let's say you're reading the Boominator thread and come across a word you don't know: write it down and research it until you know what it means.

william444555 (author)2015-09-29

Loved the tutorial, i did make something like this just in a different style, those speakers look amazing as you said it can output 115db!!!! and for a dual 15w amp!!!! i used a dual 40w +68w sub-woofer connection.

Dalletheman (author)2015-08-18

Dont know if I missed it but what kind of resistor do you use for the filter?

lutkeveld (author)Dalletheman2015-08-19

47 Ohm 3W Carbon or metal film.

JonasH4 (author)2015-08-19

Hey I made it and this speaker is simply Awesome! Soundquality, Loudness, Playtime huge win in every term exept the size xD but i think i will mount some wheels for transport.

Van Damage (author)2015-05-30

Man that is an amazing looking build, good job you guys. It looks sweet!

jedwards2 (author)2015-04-15

Hey I'm interested in making a boominator of my own after reading this and most of saturnus's thread. Could you you help me put together a list of materials?

lutkeveld (author)jedwards22015-04-15

Cool! Send me a PM and we can work it out.

chemacky (author)2015-03-22

I notice the original boominator has solar panels - are they easy to add into this design? For example, I have an 18v 28w solar panel that I'd love to be able to use to charge something like this on the odd occasion. Not permanently built in. Could the accusafe deal with the power of something like this solar going straight in instead of the mains?

lutkeveld (author)chemacky2015-03-23

Yes you can. With higher power panels like yours its recommended to use a charge controller. You only need 10W to make the battery life 'infinite'.

chemacky (author)lutkeveld2015-03-23

Thanks for the reply. Does the accusafe circuit not act as a charge controller? Or do you need a separate solar charge controller as well?

lutkeveld (author)chemacky2015-03-24

No it just acts as switch between psu/charger and battery and a low voltage disconnect. With a charge controller you transform the panel in a charger so you can hook it up to the accusafe

chemacky (author)lutkeveld2015-03-24

Ah ok. And is any of this switching automatic? I notice the accusafe has a number of buttons...?

lutkeveld (author)chemacky2015-03-24

Yeah the switches are just to turn the system on and off

chemacky (author)lutkeveld2015-03-29

How are you charging the SLA battery? I can't quite seem to figure that part out. At first I just figured when you plugged into the AC it would run the PSU and charge the battery, but I'm not so sure that is the case. Can you please help explain this to me? Thanks!

lutkeveld (author)chemacky2015-03-30

The AC input is split to a charger and PSU. The Boominator has two operation modes; not plugged in (battery coupled to amplifier) and plugged in (PSU to amplifier, charger to battery). The PSU/charger config is because it's bad to discharge the battery while its being charged.

chemacky (author)lutkeveld2015-03-30

Ok, I understand. What charger did you use? Do you have a wiring diagram anywhere?

Iglum (author)2015-03-28

So you did not chamfer or use a round over bit on the edges for the woofer holes?

lutkeveld (author)Iglum2015-03-28

Only the inside, otherwise the grill wouldn't fit. Didn't do the outside because then the strips wouldn't have enough area to stick to.

Iglum (author)lutkeveld2015-03-28

Yeah i thought so. I got some rgb led strip and a sound activated controller but i'm thinking of putting it on the wagon i'm building for the Boominator instead.

lutkeveld (author)Iglum2015-03-28

Don't rely on the glue that's on the LED strips by the way. That stuff is weak, put some superglue between it.

Iglum (author)lutkeveld2015-03-28

Ok good too know. The wagon is going to be made out of square tubing so im going to secure the led using cable ties.

oradlak (author)2015-03-27

Upload the video

lutkeveld (author)oradlak2015-03-27

Which one?

oradlak (author)lutkeveld2015-03-27

video of this boombox playing music

lutkeveld (author)oradlak2015-03-27

As said somewhere else in the comments: I don't think a video represents how it sounds. If I would add one, it would be to demonstrate the LEDs flashing. User Anders202 already has a video up with his version of the Boominator if you want to watch a video of it playing music.

oradlak (author)lutkeveld2015-03-28

how can I find this video

lutkeveld (author)oradlak2015-03-28

Just search for Boominator on youtube and some vids will pop up: https://www.youtube.com/results?search_query=boominator

salmansheikh (author)2015-03-23

very nice. any videos of it playing something would be cool and helpful for deciding whether to attempt a similar build.

lutkeveld (author)salmansheikh2015-03-24

Can be done, but I think that a video doesn't really do justice of the sound. Anders202 has a video of his version of the Boominator on Youtube, have a look there.

salmansheikh (author)lutkeveld2015-03-24

okay thanks :)

richms (author)2015-03-23

Very nice build there.

Only changes I would make would be a better DC socket than a cigarette lighter one. Probably a powerpole or similar latching one since I have no end of problems with the cigarette lighter plugs pushing out under their own spring.

And RGB. Gotta have RGB lights ;)

Ive made a small box in the past which was basically a 2 10" car woofer box with some horrid tweeters on it, and I screwed a lepai amp to the back of it and used it with a car jumpstarter pack for power. Totally unportable compared to this as it was two boxes basically. And as they were car "subs" they had a horrid gap in the midrange.

Do you know the total weight of it? And is it single person carriable with the handles on opposite ends like that?

lutkeveld (author)richms2015-03-24

The point of the DC socket is that we can use accesoires that are designed for it; USB chargers, cigarette lighters, voltmeters etc. I agree with you that the connection is worthless, but unfortunately it's the industry standard (kinda like micro usb). If it would be a pure DC passtrough I would use SpeakON or PowerCON.

We didn't really need RGB. It also adds complexity, cost and power usage.

You can one-man carry it, but not for long distances; 90cm wide and ~25Kg heavy.

bubbastich (author)2015-03-19

there are no measure ments or demotions any where what if i wanted to build this i wouldn't know where to start or what to cut

lutkeveld (author)bubbastich2015-03-20

I added a download link to the sketchup drawing in step 1.

fmanning (author)2015-03-19

can I add bluetooth to this?

lutkeveld (author)fmanning2015-03-19

You sure can! I've developed an efficient BT4.0 board with autoswitching between BT and AUX that runs on 7-28V but I haven't received my circuit boards yet. Once I get those I'll probably add it to this build.

For the time being we use a USB charger in the cigarette socket and stick a USB BT stick in it. Then we connect the output to the amplifier input.

johnny.engberg.1 (author)2015-03-19

So someone finally made an instructable of my 8 year old design. Nice work.

Phoghat (author)johnny.engberg.12015-03-19

obviously, it wasn't you

"Do, or do not. There is no try"

lutkeveld (author)Phoghat2015-03-19

Johney Engberg, aka Saturnus, is the guy I thanked for the design in the introduction post. If it wasn't for him I would probably still be trying my luck on car audio drivers. When I first read the thread I didn't understand a lot of the design decisions, but now I do. Everyday I learn and my projects get more awesome :)

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