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.
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. https://www.diyaudio.com/forums/cla...b-ultimate-party-machine-421.html#post3602024 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, 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.
No I did not use any stuffing. I remember that Saturnes said the normal boominator should not have any stuffing.
Hope I'm not too late, but I got mine from Bluearan. Decent price and posted to France. Great customer service too.
So I don't have a spine at all at the moment. Based on your post, I am guessing that for a mono halfinator having no spine and back of speakers just being suspended rather than fixed to the spine, will make little to no difference? What do you reckon? So I could build the mono halfinator without a spine?
You could build it without the middle brace, but the whole reason it is part of the design is for structural purpose. It keeps the top, bottom and sides together, and by glueing the back of the drivers to it, it also braces the front and back baffle. This way the structure is so solid that 12mm birchply is enough, keeping the speaker light and tough.
If anyone in the States is interested in a pre-built boominator (without amp/battery, but including xovers) I have a couple laying around not being used. Sorry, just getting too old to move them around. Built of baltic birch coated with duratex. Shipping might be prohibitive. I am in the Chicago area for pickup.
I've gone the mini route and added a sub. I know, I know, not a boominator mini then, but it sounds really good.
I've gone the mini route and added a sub. I know, I know, not a boominator mini then, but it sounds really good.
I agree that Bluearan is a great supplier, but when I made that post they were not available. But now, they are available for back-order and are due 30 July 2020 if anybody is interested.
You need to start by reading. There's a great pdf on this forum with much of the info you need. Boominator digest.
What you are describing is a halfinator and all electronics needed are detailed in the digest. Good luck!
So the halfinator is built (except battery). It is running very nicely of mains power and I am waiting for a BMS to arrive so I can get the lifepo4 battery built.
I do have a question about volume. My DC adapter is variable voltage and I thought increasing or decreasing voltage would affect the volume, but it does not. Am I correct in understanding that if insufficient voltage is supplied for a given volume demand, I will notice due to clipping? And therefore the optimum gain adjusted on the circuit board is such that at full volume, gain is set such that it is a bit lower than the point clipping occurs?
Following on from this, I've decided to build a 19v battery, but my gain is set to maximum and sound is great, when I decrease voltage sound is still great and volume remains the same. How can therefore get the volume higher and make the most of the 18v? A pre-amp? 19v battery seems a waste if I am getting the same volume and sound quality at 12v.
I also accidentally broke my amps gain dial trying to turn it up, so it is still stuck on max.
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What amp are you using?
I use a 1x 100w TPA3116 based module from Sure/Wondom.
I run mine off a simple 12v 7Ah lead-acid battery. I have also noticed no increase in output volume when hooking it up to 24v, but it does seem to be able to play louder before audible distortion. With 18-19v I think you are in a good place.
On the risk of being corrected by someone more knowledgeable; I think it is safe to say a 19v power supply will give you BETTER quality at max volume compare to 12v. Note that voltage also drops with a heavy load (depending on the capacity of the battery how much). When I turn my speaker up all the way I see the number on the voltage display decrease immediately, only to return when the volume is turned down again. You will want to stay well above the minimum supply voltage of the amp.
In my experience the bottleneck in this configuration really is the source. Smartphones are not designed for driving power amplifiers, but for headphones and earbuds. On top of that most phones display significant distortion over 75% output.
Hooking up my boombox to a pc as sound source already makes a small difference, but it's nothing compared to having a dj mixdeck between the source and the amp. It plays way louder with less distortion.
I'd also like to note that cable length and quality are also important. Use a decent audio cable and keep it as short as possible.
The solution to this problem would indeed be a preamp. I've tried adding a simple NE5532 module, but it added a lot of hiss and distortion to the system. It was also a poor quality module and I plan on designing a well isolated preamp specifically for it some day. A separate battery might be required, or some way of isolated it from the amp.
When it comes to battery life it is no issue, a opamp usually draws only a few milliamps.
Amplifiers will clip when they are being driven beyond their max capability. When the amp has a higher supply voltage it can put out a stronger signal without having to compromise by cutting the peaks (clipping). So yeah higher supply voltage will make for a cleaner signal when played loud. This is not the same as playing louder. You cannot control the output volume by raising or lowering the supply voltage. If you want volume control, add a potentiometer. But this would make it even harder for a phone to drive the load, hence why potmeters are usually accompanied by a volume buffer/preamp
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Thank you Hofmann. Your post reinforces my thinking.
TPA3116 mono, I guess similar to yours. - TPA3116 D2 TPA3116DA DC 12V 24V 100W Mono Channel Digital Power Audio Amplifier Board TPA3116D2 Large Capacity Board|audio amplifier board|dc dcdigital amplifier board - AliExpress
I get clipping from around 14v and below on laptop and on phone no sound quality is diminished all the way down to my min voltage of 9v. So I know I can still push the amp a fair bit before sound quality starts to be compromised.
I will get a pre-amp and just to be sure I will make a bypass switch so I can use my speaker at quiet volumes without the need for the preamp (and associated standby current draw). At high volumes for sure the additional draw of a preamp will have no impact whatsoever.
I have found this preamp, with built in bluetooth, AIYIMA Amplificador Bluetooth Tube Preamplifier Fever Hifi 6J5 Bile Vacuum Tube Preamp JRC5532 Pre Amplifier Tone Control Board|Amplifier| - AliExpress - it says 12v only - any thoughts on whether running it on 19v will burn it out? Thanks!
TPA3116 mono, I guess similar to yours. - TPA3116 D2 TPA3116DA DC 12V 24V 100W Mono Channel Digital Power Audio Amplifier Board TPA3116D2 Large Capacity Board|audio amplifier board|dc dcdigital amplifier board - AliExpress
I get clipping from around 14v and below on laptop and on phone no sound quality is diminished all the way down to my min voltage of 9v. So I know I can still push the amp a fair bit before sound quality starts to be compromised.
I will get a pre-amp and just to be sure I will make a bypass switch so I can use my speaker at quiet volumes without the need for the preamp (and associated standby current draw). At high volumes for sure the additional draw of a preamp will have no impact whatsoever.
I have found this preamp, with built in bluetooth, AIYIMA Amplificador Bluetooth Tube Preamplifier Fever Hifi 6J5 Bile Vacuum Tube Preamp JRC5532 Pre Amplifier Tone Control Board|Amplifier| - AliExpress - it says 12v only - any thoughts on whether running it on 19v will burn it out? Thanks!
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Last year I built a boominator, and this year I want to build the halfinator.
I'm thinking of maybe building the halfinator more like the soundboks 2, with all speakers facing one way (no 360° design). Is there anyone here that has done this?
2 piezo tweeters and 2 HP10W speakers over and under each other, with a bassport in the left corner of each chamber.
Also, have anyone tried to use 2 mono TPA3116 amps? One for each chamber? (2x8ohm speakers in parallel for 4ohm, on each amp?)
I'm thinking of maybe building the halfinator more like the soundboks 2, with all speakers facing one way (no 360° design). Is there anyone here that has done this?
2 piezo tweeters and 2 HP10W speakers over and under each other, with a bassport in the left corner of each chamber.
Also, have anyone tried to use 2 mono TPA3116 amps? One for each chamber? (2x8ohm speakers in parallel for 4ohm, on each amp?)
I also want to try this. As the halfinator is typically mono, the chambers are separated by a layer that is full of holes, essentially making the speaker have only one chamber.
On this basis, in my planning, I was only going to use one bass port. I'd like to hear thoughts on this.
My main concern with stacking the speakers so they face the same direction is one of structural rigidity. The halfinator is made to be extremely structurally rigid, thereby needing only 12mm wood. As soon as you stack it, you lose that rigidity.
I have one tpa3116d2 mono amp for the entire halfinator with the speakers paralleled to 4ohm. Not sure what you mean, but wiring diagrams are in the boominator digest pdf.
On this basis, in my planning, I was only going to use one bass port. I'd like to hear thoughts on this.
My main concern with stacking the speakers so they face the same direction is one of structural rigidity. The halfinator is made to be extremely structurally rigid, thereby needing only 12mm wood. As soon as you stack it, you lose that rigidity.
I have one tpa3116d2 mono amp for the entire halfinator with the speakers paralleled to 4ohm. Not sure what you mean, but wiring diagrams are in the boominator digest pdf.
I've tried about every variation of tpa3116 on the web. Even you win the quality control lotto most of them require extensive modification before they are usable.
I ended up with Wondom/Sure audio boards for various projects. I cannot stress enough how much better they are than all the other ebay/ali crap. Their basic 1x 100w is affordable enough. I am running the 1x 100w version with bluetooth. It provides connector sockets to plug in status leds, on/off switches and volume control. It even has a build in MPPT charger so anything over 12v will charge your battery. I hook up a solar panel directly to it and it does the charging for me.
WONDOM | STORE
Hofmann said:
Thanks! I have never heard of this amp but it is basically everything I have been looking for. Wish I'd found out a bit it a few days ago before buying a bunch of stuff on Ali to try and improve the speaker. I'll buy a Wondom bluetooth mono amp, much cleaner solution than pre-amp and ground loop isolator and separate bluetooth module and potentially worse sound quality and potentially having to mess with tpa3116 board.
That said, I am tempted to at least swap out capacitors on the tpa3116 and seeing what difference that makes. I read somewhere that that should eliminate the low gain issue and at least make the pre-amp obsolete. Any thoughts on this? This is my TPA3116D2 and it comes with 6 x 35v 330uF capacitors as stock. Do you think upgrading these to 35v 2200uF could improve things?
TPA3116D2 mono
My experience with separate preamps or bluetooth modules sharing the same power supply has only been dissapointing.
I recently bought 2 of those exact modules just to see how much I can improve them. They have not arrived yet.
I have a dual mono version of different tpa3116d2 where I swapped out the power filter caps. It had 5x 470uF which I swapped for 2200uF. The difference was in sound quality was huge, but I doubt it'll do much for the overal volume.
Also since they only act as a power buffer to filter out ripples and such, I'm not sure how much it even is applicable when using a battery and sort wires.
As a disclaimer I barely know enough about electronics to have the right to hold a soldering iron.
In my halfinator I find that the 1x 100w Wondom board requires no preamp.