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Class D Switching Power Amplifiers and Power D/A conversion

The Boominator - another stab at the ultimate party machine
The Boominator - another stab at the ultimate party machine
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Old 19th April 2020, 05:41 AM   #6761
Hofmann is offline Hofmann  Netherlands
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Join Date: Apr 2018
Quote:
Originally Posted by eshamp View Post
Awesome, thanks, this definitely puts my mind to rest. I've learnt so much in the months spent researching this, but still know so little!

I understand the logic behind the speakers working together by being back to back, but as you say that doesn't mean it actually makes much (or any) difference in real life. I notice no back to back speakers in the soundboks, so maybe the difference isn't that big after all.

Based on the project spend so far, a soundbok is actually starting to look like a rather attractive proposition! Great work he's done there!
The fact that the magnets are close together doesn't have anything to do with the +3db rise in SPL of a bipole speaker. As far as I know bipole speakers are double the volume output because they push air against eachother, creating more air pressure inside the enclosure with the same amount of Watts, compared to 2 of the same drivers both facing the same way.

This might be a bit of a no brainer, but the HP10W drivers are mounted from the inside, not from outside. Just saying in case you weren't aware of that. That might explain the 18mm gap.

Other that that, having build 3 halfinators, I can really recommend keeping the side panel on the battery side detachable. You don't want to seal all the electronics off.
I also learned the hard way that you will want to keep the bottom panel detachable as well, all be it only when cables connections come losse at the speakers. I use a foam gasket tape along the edges, then put the bottom panel in place with lots of screws.

The battery you have might be overkill, but if that's what you have, then I'd say use that. I find 5-7 Ah more then enough.
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Old 19th April 2020, 01:10 PM   #6762
eshamp is offline eshamp  United Kingdom
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Join Date: Mar 2019
Quote:
Originally Posted by Hofmann View Post
The fact that the magnets are close together doesn't have anything to do with the +3db rise in SPL of a bipole speaker. As far as I know bipole speakers are double the volume output because they push air against eachother, creating more air pressure inside the enclosure with the same amount of Watts, compared to 2 of the same drivers both facing the same way.

This might be a bit of a no brainer, but the HP10W drivers are mounted from the inside, not from outside. Just saying in case you weren't aware of that. That might explain the 18mm gap.

Other that that, having build 3 halfinators, I can really recommend keeping the side panel on the battery side detachable. You don't want to seal all the electronics off.
I also learned the hard way that you will want to keep the bottom panel detachable as well, all be it only when cables connections come losse at the speakers. I use a foam gasket tape along the edges, then put the bottom panel in place with lots of screws.

The battery you have might be overkill, but if that's what you have, then I'd say use that. I find 5-7 Ah more then enough.
Thanks for the info.

Unfortunately, it is an incorrect plan, Saturnus commented on it, but I didn't see before I got the wood cut. The Boominator - another stab at the ultimate party machine I edited the sketchup so that there are routed slots all round for tight fitting of each panel, so I think I should be able to screw together and still keep it pretty air tight without having to glue any panels. Definitely a good idea not to glue given access may well be needed in the future.

For the battery, I'm running at 19.6v, so approximately twice the power consumption vs 12v. So if you are at 12v, then we would get roughly the same playtime. I'm hoping for around 7-8 hours at high volume.

Did you stuff any of your speakers with wool or other insulation?
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Old 20th April 2020, 02:25 AM   #6763
horst303 is offline horst303  Australia
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Join Date: Nov 2009
Location: Sydney
Quote:
Originally Posted by Hofmann View Post
The fact that the magnets are close together doesn't have anything to do with the +3db rise in SPL of a bipole speaker. As far as I know bipole speakers are double the volume output because they push air against eachother, creating more air pressure inside the enclosure with the same amount of Watts, compared to 2 of the same drivers both facing the same way.
No, the way the speakers are facing doesn't make any difference, on the inside of the box. The design consideration for opposing drivers is that it lends itself to a smaller box, and that you get a smoother polar response, the downside is that it's not that great inside a house, which is more than likely the reason soundboks, didn't go for opposing drivers, because it does limit your market, which for the boominator was wasted kids at Roskilde listening to Scandinavian death metal.
Saturnus speculated that there was an additional 1-2 dB that you get from putting the magnets close together. You do actually get 6dB extra just from doubling drivers, 3 from doubling surface area and 3 from mutual coupling, that's not speculation, you can actually measure that.
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Old 20th April 2020, 03:16 PM   #6764
Hofmann is offline Hofmann  Netherlands
diyAudio Member
 
Join Date: Apr 2018
Quote:
Originally Posted by eshamp View Post
Thanks for the info.

Unfortunately, it is an incorrect plan, Saturnus commented on it, but I didn't see before I got the wood cut. The Boominator - another stab at the ultimate party machine I edited the sketchup so that there are routed slots all round for tight fitting of each panel, so I think I should be able to screw together and still keep it pretty air tight without having to glue any panels. Definitely a good idea not to glue given access may well be needed in the future.

For the battery, I'm running at 19.6v, so approximately twice the power consumption vs 12v. So if you are at 12v, then we would get roughly the same playtime. I'm hoping for around 7-8 hours at high volume.

Did you stuff any of your speakers with wool or other insulation?
No I did not use any stuffing. I remember that Saturnes said the normal boominator should not have any stuffing.
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Old 22nd May 2020, 08:07 PM   #6765
kernelle is offline kernelle  Belgium
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Join Date: May 2020
Location: Belgium
Sup guys, long time lurker on this thread and currently gathering parts for my upcoming Boominator build. Does anybody have any leads on the P.Audio HP-10W? They seem almost impossible to find.
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