The Boominator - another stab at the ultimate party machine

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ALJ

Member
Joined 2010
I've built two stereos and both of them distort at about 85%. It can still play louder but as gmarsh says, the tweeters will be distorting. Try out different sources. For instance, a laptop has a more powerful signal and will distort earlier than e.g. an iPod because of it. And yes, it's hard to explain drunk people why it doesn't help to turn the volume all the way up. :)
 
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osny

Member
Joined 2011
Is this a problem I can fix, or? What exactly do you mean by the amp is clipping?

If I disconnect the tweeters and only listen to the bass, 100% is fine, loud and clear :)

I just want this problem out of my mind, give me a solution!

gmarsh said:
Is it possible you're clipping your amp at volume levels >85%? Clipping creates pretty horrible sounding distortion, and a fair bit of that ends up coming out of the tweeters.

Fairly simple to find out if you're overexerting your tweeters or clipping your amp - increase the value of the series resistors a lot (up to 1K or something) which will attenuate the tweeter, put your ear by a tweeter and see if it still starts to break up at the same 85%+ volume level. If it still happens, you're clipping the amp.

Or if you can borrow an oscilloscope, just watch one of the amp output terminals - if the output bounces off ground or the +12V rail, it's your problem.
Click to expand...
 
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barbfa

Member
Joined 2012
regarding joining the plywood pieces to each other, I'm reading up on different woodworking joint techniques. Have anyone tried anything different than a ordninary butt joint plus screw and glue?
Found this scridb docu which mentions rabbets and dadoes halfway down, seems easy enough to do with a router. This seems to be the consensus on the strongest joint for plywood, rabbet half the thickness of each edge to be joined together.
Adding aluminum profile to all edges and corner protectors would help me too of course.
Probably, the strongest and easiest joint for plywood would be to add a square-cut wooden piece (aka corner block) along the joint, screw and glue. But doing this inside the box would change volume and outside the bow would look hideous.
Question: if one would learn enough to recalculate the boominator with these corner blocks inside and thus get the correct volume, would the changed inside shape affect the sound quality /or volume at all?
 
Saturnus

Saturnus

Member
Joined 2005
The Boominator is made with rebating everywhere already. The sketch-up drawing I've done is only the easy DIY version where you don't need routing skills or CNC machinary. It's assumed that if you have enough skill with a router or CNC machinary available, you also be able recalculate the measurements accordingly.

Corner blocks or anything else is not needed, especially not if you use epoxy glue. In fact, screws aren't necessary with rebating and epoxy glue either. They're mostly there so that I could screw everything in place to make sure it fit before I applied glue. If I were to build one today, I'd not bother with screws at all.
 
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barbfa

Member
Joined 2012
Well, I have insane friends. Crust-punks are often able to destroy things like stones and houses (not that I will play crust on my boomi much).
But I also guess that there is no reason to build a box that can stand up to several times more abuse than what is inside it will take anyway...
I'll see if I have the time over to play around with rabbets and dadoes when building it, half the fun is learning new stuff.
 
Saturnus

Saturnus

Member
Joined 2005
barbfa said:
Well, I have insane friends. Crust-punks are often able to destroy things like stones and houses (not that I will play crust on my boomi much).
But I also guess that there is no reason to build a box that can stand up to several times more abuse than what is inside it will take anyway...
I'll see if I have the time over to play around with rabbets and dadoes when building it, half the fun is learning new stuff.
Click to expand...

Epoxy glue is stronger than the wood itself so it will not break. It'll be easier to try a put an ax through it.

I remember one builder, the yellow one, who after building his dropped it of the lorry of his truck when he went over a bump and it dumped out the back at 40 kmh. Result: One scratch corner. That's it.

I have also by accident dropped mine from 2 meters up, twice, and it survived fine. Although a wire came loose on the amp inside so music was cut until I got it out and refitted it.
 
danielwritesbac

danielwritesbac

Member
Joined 2007
startfetch.com
osny said:
Is this a problem I can fix, or? What exactly do you mean by the amp is clipping? If I disconnect the tweeters and only listen to the bass, 100% is fine, loud and clear :) I just want this problem out of my mind, give me a solution!
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Bi-Amp stops this problem, but you need a treble amp.
Buy a Sure TA2024. Don't hook it to the woofers. Use it only for tweeters.
P.S.
It is also helpful to use tiny value caps sized small enough to block bass to the input of the treble amp.
It is also helpful to have ordinary speaker crossover parts (at least a series cap) at the output of the treble amp.
P.P.S.
Even a weak little PAM amplifier is strong enough to power tweeters, so perhaps my recognition of Sure's super loud TA2024 is overkill. May I suggest that you do some searches and some reading up on bi-amp.
 
M

mpaev

Member
Joined 2012
New to the game :)

Hi I'm new in building the the boominator. (Halfinator)

At this point I've bought 2x HP-10W
and the AMP6Basic

I'm looking at buying these things.
Can it be used ? :)

Batteries: 3X
Harley Benton HBAC-30 Replacement Battery - Thomann danske Cyberstore

Piezo 2x
Monacor MPT-001 - Thomann danske Cyberstore

Solar panel 2x
8V 250mA OEM Solar Panel | Small Solar Panel - Innovative Solar Solutions

I'm in doubt which charge control I should use for the solar panels and if the 2 panels is enough to power up a halfinator.

Oh and by the way, I have non what so ever knowledge of speakers and its like ;) but that's not stopping me ;)
 
gmarsh

gmarsh

Member
Joined 2004
osny said:
Is this a problem I can fix, or? What exactly do you mean by the amp is clipping?

If I disconnect the tweeters and only listen to the bass, 100% is fine, loud and clear :)

I just want this problem out of my mind, give me a solution!
Click to expand...
Clipping: Your amp, powered from +12V, is only capable of driving +-12V into the load connected to it. If you try to drive more power out of it, the output won't go beyond that limit - it'll "flat line" at +12V or -12V into the load, creating distortion.

First of all, find out if it's the problem - raise the value of the tweeter resistors and listen for the same noise coming out of the tweeters at the same "85%" threshold. If it goes away, get new tweeters, if it remains, here's your options:

- deal with the fact that "85%" on your MP3 player is full volume.
- get a more powerful amp
- preprocess your MP3 files with multiband dynamic range compression to make them louder without driving the peaks up - AudioProc - High Quality Broadcast Audio Processing for Winamp makes a broadcast audio processor plugin for Winamp which should do the trick in "webcast" mode. "85%" will still be full volume on your MP3 player, but it will sound louder.
 
R

Rolschau

Member
Joined 2011
So my boominator i coming together fine. I have one problem though - with my TA2020 amp came a power cable for a regular 220V outlet. I somehow have to convert to get this cable to fit my SLA battery. I guess I have to cut off the AC-adapter, but I'm unsure of what I do next.

I tried cutting off the adapter on a power cable from an pc and inside the cable was a bunch of wires outside another cable with a bunch of wires. What goes to + on the battery and what goes to -?
 
K

kblnig

Member
Joined 2010
The usual way of doing it is

- is the surrounding of the plug
+ is the pin inside

So if you cut your cable and you have an Ohm-meter you could meassure the connection from the plug to the cables and see what goes where.. Some power supplies have a shield surrounding the cable which you could just connect to - in both ends (i doubt your amp charger has that though)...
 
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