The Boominator - another stab at the ultimate party machine

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#5,063
Hello, God Dag,

I am a long time lurker, infrequent poster... over here in the US. (my mother happens to be Danish, which adds some warmth to this thread for me)

I thought I would show you a project I've been working on, and get some pointers.

Its a design that utilizes a bit of the boominators science, but lets non-tech people be somewhat part of the design and construction. And it is cheap, simple and very loud and clear.

My plan it to make the design available online for people to build, and have the cnc files available as it is all designed to be cut on a router table. I may also have a run cut on a cnc, and sell them online at cost. It all fits in a flat rate postage box.

Then I will have a buying list for people to purchase the exact right parts.

You will understand it just by the photos. Four thrift shop speakers, 8 or 6 ohm. These particular ones are all 6 ohm run in parallel. The infamous Lepai amp. Small SLA battery.

1) The loudest it plays is with the tone controls off, but it actually sounds wonderful at lower volumes with the controls on, high bass.

2) With a fresh battery, the amp kicks off with the 3 ohm load at about 80% volume. Concerned about how this harms the amp. It is much less likely to do so when the battery voltage lowers a bit.

3) I brainstormed reducing the volume of the enclosure to crudely tune them up a bit. Unsure if that would be worth the effort.

4) Did I mention that this is designed to be bicycle panniers? This one is huge and weights 40 lbs, which works fine on heavy duty bike racks. People will need to make lighter ones for lighter duty racks. (it isn't assembled in the photo)

Do you think it would be worth the added complexity to ask people to add a highpass crossover? The very low end of these ported boxes is surprisingly fun to have present when indoors.

I am thinking about starting a thread to get people's input on this design, any advise on where? I could do it here, or instructables, or a blog...

Thanks again for everyone's involvement with this!

Warmly,

Tor Clausen
m u s i c a l f u r n i s h i n g s
 

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#5,065
I'm annoyed
Ordered 8 of the dayton tweeters from interteknik as they said they had them in stock, they took my money and the next day I got an email to say they wouldn't have any for 8 weeks.... Outrageous, won't order from them again
BJ
 
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#5,067
saxomann said:
I have never change settings since iv been happy whit it and havent got time to Experiment. Hope that others have so we can get some discussion about it.
Here are settings i use: http://sdrv.ms/1f2xbuw
Click to expand...

Could you check the link to your drive? It doesn't work for me and I'd like to look at what you did....I have placed my order for the SN10MB drivers. Now it is time to get serious!
 
#5,071
The start of the build is approaching and I have been trying to suss out a few things regarding speaker placement and grills. (Mini V2)

I am not super keen to use cooling grills so have been looking onto alternatives.
One thing I just tested with my current sp60 boombox is that with heavy bass the cone moves out further than the foamy guard thing around the speaker.

I had been hoping to put some sort of grill immediately after the driver in the internal 6mm ply that houses the driver. I may still be able to route into the external 6mm from the inside.
That would leave 2mm extra clearance.

Do you think that 2 times 2mm rods spanning the drivers would be stiff enough to maintain form over the years with the odd knock? (Also is brass strong enough or must it be steel?)

My current unprotected boombox has made it safely around the world and to various festivals only to be attacked on two occasions by my little nieces and nephews..

Regarding tweeter placement, is there a technical reason for it lining up vertically with the bass driver? (I may need to move it into the upper corners so I can route more aggressively)

Also is it best to seat the tweeters on the outer 6mm ply to maintain their crazy wide dispersion?
Or is it ok to seat them against the outer of the inner 6mm ply and then route the outer ply?

Thanks in advance
 
#5,073
If the speakers were mounted on the outside of the box it would change the internal volume and therefore the tuning of the speakers. Just as importantly it would also create an extra 24mm gap between the speaker magnets making magnet to magnet coupling difficult....
Saturnus could probably give you even more reasons but this is my basic understanding.
BJ
 
#5,074
There also the simple fact that most pro drivers are meant and designed to be mounted from the inside and sound best that way. It's also why the hard cardboard or rubber ring on the outside is called a mounting gasket.
 
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#5,076
Hey I am going to build a festival stereo. I am inspired by the boominator but I want to make something different so it is bigger and only speakers on one side.

I have made a 3D model with everything:

Boombox skiss forum - Ladda-upp.se

I will use MDF to build it, hopefully with 19mm. If not I will use 16mm.
(The 3d model is made with 19mm thickness)

This is what I am planning to use:

4x P.audio HP-10W - Ljudia - Multimedia Hemelektronik Karaoke PA anläggning DJ utrustning Ljus utrustning

4x Diskanthorn - Monacor MPT-016

2x Celestion TF0615MR 8R - Ljudia - Multimedia Hemelektronik Karaoke PA anläggning DJ utrustning Ljus utrustning

Crossover:
New Boss BX55 2 3 Way Electronic Crossover with Remote Bass Control 0791489110167 | eBay

I am going to tri-amp.

Now to the big question, what amplifiers to use...

I was planning to use:

2x Amazon.com: 2x100W @ 4 Ohm TK2050 Class-D Audio Amplifier Board: Electronics

1x Amazon.com: 2x50W TDA7492 Class-D Amplifier Board: Electronics
(for the midrange speakers)


Other amplifiers I had in mind was for example "Muse m50".


For power supply I will use 2x 70ah+ batteries ( of course connected in series if I will use amplifiers that can use 24v)


As always for festival stereos the most important is the music volume. I need help to find the best setup with the amplifiers to get the most out of this thing.


I know it will be very big and heavy, hopefully the wheels will make it fairly portable though. It is also good if it is heavy if you think about thieves. If we just lock the wheels, it is very hard to take away...



Thanks!
 
#5,077
In the drawings for the Mini V2 it looks like Saturnus has placed the drivers with the driver gaskets flush behind the ply as opposed to into the hole in the ply. (The SP60 is 56mm from the back to the steel mounting plate and there is 60mm allowed in the drawing).

Was the gasket placement deliberate and if so could you please explain why and how to mount it with the steel mounting plates?

Cheers
 
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