The Boominator - another stab at the ultimate party machine

[Saturnus]

300x300x900mm

All outer ply is 12mm. Bracing is 8mm. Center volume is 66mm wide.

That gives 23L total volume when all drivers, ports and bracing volume is deducted.

[dododoo]

thanks for the replies everyone and thanks for the measurements saturnus - i'm sure you must get bored of talking to ignorants like me who keep asking stupid questions!

i've been thinking about things a bit more and re reading the thread and takign notes and apologies for thinking of murdering aperfectly amazing, finely tuned design, that i have no real brains to do but the heaviness scares me and i can't find another design i like as much that weights less.... :-)

so it seems like i can't do much about the Q without paid for software which i don't have so i'll just have to ignore it i spose and maybe make the gain graph a bit more peaky!? ( as liek the alphalite shown below )

i think i found two potential driver / box combos that will be lighter for me, ( at the cost of loundess ) but want to ask if anyone can see anything obviously wrong with my results. just so i know if the last three days and nights have been any use at all :-)...

the two drivers i think might be able to do it for me are the:
- eminence alphalite 6a ( weight 1kg each - saves 8.6kg w/ four, depth 61mm, cost £65 each ( ouch !! )
- fane sovereign 8-125 ( weight 1.75kg each - saves 5.6kg w/ four, 94mm, cost £25 each (better! )

i got the frequency response graphs of each and overlaid them on the one for the HP10w to see how they compare. that image should be here.
The black line is the alphalite 6a, red is the fane 8-125 and the blue is the HP10w.

it seems to me that the alphalite is pretty good in this comparison but the fane seems pretty patchy because of it's wildly changing output and -3db drop as it goes from 80 to 100hz and the 4db hole in the 130 to 180hz area. Could it really be this bad? - would they sell something that looks as messy a response ( i got it from their catalogue !?)

the reason i am asking is that in WinISD it looks much better than the alphalite when i compare them both to the hp10w
here are the gain curves
and here are the volume curves with all three.
( there are two drivers in each box and they are getting 10w at 1m )

the fane one is doing what saturnus said of peaking at twice the frequency of the box tuning, whereas the alphalite definately is not and it also has a very steep curve at the low end which might not have enough bass? It is however at -3db at 100hz like jimtegel just suggested.

i know they're not as loud - i'm prepared for a bit of a drop in volume in exchange for weighteasi, i need to be able to move it around easily on a bike or i won't take it w/ me in the first place!

and even if the alphalite is ok i also have the problem of the alphalite being way to shallow - i wouldn't be able to stick them magnet to magnet and have a square section box - but i could put a light block in between to keep the strength idea - loosing the magnet to magnet 1/2 db gain.

anyone any thoughts? ( you can tell me just to shut up and build the original and get stronger legs but i might cry! ;-) )

cheers,
simon

[MarkAron]

I am attemping to build a Boominator too, but instead of four HP-10W's, i only want two. Would I then have to change the volume of the speaker chamber? I tried using WinISD, but it's a bit too complicated for me.

[Saturnus]

Pretty sure I answered that question already in this thread but yes, half the drivers means half the internal volume. Note that it does not equal half the size though.

[MarkAron]

Ok, thanks I am still considering making it with four speakers as the original design to get the best possible soundsystem. Just wanted to hear in case I'm short on cash.

Saturnus: Is it possible that the sketchup-file could be reuploaded? I can host the file for at long as you want. Just email me the file at xanroar@hotmail.com and I will post a link here in the thread.

[Love Below]

Saturnus.

Have you thought about useing the Boominator for inside use also?
If so are you then going to make some kind of connection so that you can plug it to an normal outlet?

[Mr_Oasis]

Saturnus:

You mentioned that you had found the HP10W drivers in the 4 ohm version. I've been looking around for the name HP10W4, but the only hit I get is an australian webshop which have them out of stock. When I mailed Intertechnik, they said it wasn't possible to get them to carry them unless I agreed to buy 100 pieces.

Is it possible that you could provide a link to where you found the drivers?

[ThokN]

I think we have settled for the final design of our new boominator, but still a couple of questions remain, which I hope you (or other followers) can answer, since you know the internals of the boominator.

1. I still haven't been able to understand how we should wire up the Amp9 to the speakers. My problem is that it has 4-channels, while the 4 speakers of the boominator serves as only 2 channels since they are paralleled. And I think I've understood that if you bridge the 4 outputs into 2 outputs, it will double the resistance from 4Ω to 8Ω on each of the two resulting channels. But since the 4x8Ω speakers are paralleled, they will act as 2x4Ω speakers, which the amplifier wouldn't like when bridged. So...how do we wire the outputs to get the full power from the amplifier into the paralleled speakers?

2. I've seen you mention the Sure 4x100W amplifier on the Roskilde-forum, and we are very tempted to go with that instead because of the more power and cheaper price, but do you know if it has any significant drawbacks compared to the Amp9? Sound-quality is not important. Our main concern is power consumption(efficiency and idle), heat, and if we will be able to use all 400W into the 2 (2x2) speakers.

3. Will 2x 12V SLA's delivering a max of 2.1A each, wired to 24V even be able to drive any of these amps? Tried with an online calculator which says that 24V and 400W will draw 16.67 Amps, which sound like an awful lot to me.

These are the only two questions remaining before we will begin ordering parts, so any help will be very appreciated


Pictures are always good, so here are a couple of our Heime v.3 from Camp Fri Ost @ Roskilde Festival 2009:

[teamacc]

If heat is a concern, dont go with the sure 4 channel amp.
You might however try the 2 channel version, which can deliver 100w per channel into 4 ohm, so you could just put 2 speakers parallel to get that.

Dont bridge the 4 channel nor the 2 channel version, they WILL die (or just leave a hole in the pcb)

[ThokN]

Wow thanks for the quick reply!

My guess is that heat will be a concern since it will be put inside a small box within the boominator. Do you think the 2-channel version will be cool enough without a fan?

And when you say that we shouldn't bridge the 4-channel, does that include the Amp9? Cause the 41hz website says:
"Outputs can be paralleled for even higher outputs into very low impedance loads"

If the Amp9 is capable of that, this amp would be the one to go for if we want a louder boominator, right?