Cost of LiFePo4 is pretty good considering you have to replace the lead-acid cells every couple of years or so.
--Buckapound
--Buckapound
In most cases you also need much fewer Ah due to the fast recharge capacity. Most LFP cells easily handles 1C charge rates, that means 1h 45m recharge time. Some even handle much higher charge rates safely.
We might be able do make some kind of group buy for this, i can get batteries here for a good price.
ill just have to double check the shipping bit, but i think DHL will ship them.
ive found 1000mAh ( 1Ah) 3.2V cells for around 15 RMB here, the A123 size. so for 12 V youll need 4 pieces and for every additional ampere at 12V youll need another 4.
that means in euro's for a 2A 12.8V pack you need around 15 euro. i think this is still quite fair for LIFEp04 batteries. whe'll have to find a good source also for protection boards, or i will design one myself.
if there is enough interest i could try buying one box and distribute them.
ill just have to double check the shipping bit, but i think DHL will ship them.
ive found 1000mAh ( 1Ah) 3.2V cells for around 15 RMB here, the A123 size. so for 12 V youll need 4 pieces and for every additional ampere at 12V youll need another 4.
that means in euro's for a 2A 12.8V pack you need around 15 euro. i think this is still quite fair for LIFEp04 batteries. whe'll have to find a good source also for protection boards, or i will design one myself.
if there is enough interest i could try buying one box and distribute them.
I'm glad to see a discussion about battery types!
I've gotten pretty close to finishing my build, and (due to air travel) have had to abandon my original plan of using a LiFePo4 pack similar to Buckapound's. Transportation and time constraints have forced me to consider less optimal, but more readily-available, power sources.
Can anyone comment on using Alkaline batteries, such as D-cells, as their power source? Some datasheets found at duracell do not seem very encouraging (nominal voltage drops quite quickly, meaning I will likely need a 12-cell pack. ex: Duracell: Technical/OEM
I've gotten pretty close to finishing my build, and (due to air travel) have had to abandon my original plan of using a LiFePo4 pack similar to Buckapound's. Transportation and time constraints have forced me to consider less optimal, but more readily-available, power sources.
Can anyone comment on using Alkaline batteries, such as D-cells, as their power source? Some datasheets found at duracell do not seem very encouraging (nominal voltage drops quite quickly, meaning I will likely need a 12-cell pack. ex: Duracell: Technical/OEM
I would personally be more into something like 4 of these 20C Continuous C-Rate LiFePO4 38120 Cylindrical Cells on eBay (end time 03-Aug-10 15:13:10 BST) (been on my watchlist for ever) and then a charging/protection board.
They must be available in Zhenzhen also... everything is 😉. Maybe some small tech guy in mong kok would know where to find similar LiFePo4 batteries?
They must be available in Zhenzhen also... everything is 😉. Maybe some small tech guy in mong kok would know where to find similar LiFePo4 batteries?
Thanks for the suggestion -- I'm sure someone might be interested, though (at least for me), these would not be any better than my existing LiFePo4 battery pack from batteryspace.com. I believe they sell the discrete cells and protection boards, too.
The problem is that transport of lithium batteries in heavily regulated in the US, and restricted on air travel (especially beyond a certain amount of lithium, and when the pack is not part of a laptop or other consumer electronics.) As with many things, there's probably a good chance of success simply by shipping/flying the pack undeclared.
Ultimately I wouldn't want to risk confiscation of an expensive pack (at the very least), so I'm wondering what results to expect with more readily-available parts such as alkalines..
Docman,
Nothing is forever. Just pick up some cheap D-cell holders at Radio Shack, and get on with your festival or whatever. It will be obvious that over time, this will be an expensive way to go, but will solve your problem for now. Later, you can replace them with something more permanent, like lithium cells of some type. You could even make the design modular, so battery types could be swapped out by un-clipping the battery pack and exchanging them. Best thing I ever did with my boombox is to make the whole top removable with four huge knurled screws so it's easy to get inside.
--Buckapound
Nothing is forever. Just pick up some cheap D-cell holders at Radio Shack, and get on with your festival or whatever. It will be obvious that over time, this will be an expensive way to go, but will solve your problem for now. Later, you can replace them with something more permanent, like lithium cells of some type. You could even make the design modular, so battery types could be swapped out by un-clipping the battery pack and exchanging them. Best thing I ever did with my boombox is to make the whole top removable with four huge knurled screws so it's easy to get inside.
--Buckapound
Yes, sadly, authorities have a hard time understanding that there can be different types of lithium cells, and that LFP cells are completely safe, no matter what you do to them.
Very interested...I think that you could sell them as a pack with the charger. I've had success with using the CCTV batteries off of ebay to power my ta2020 and ta2024...
12.6v 4800mah Li-Ion Batteries go for $25 delivered. I remove the protection circuits and they run fine. I'm just careful that I don't run them down all the way...and I mount them inside the speaker...anyways,
I found these...
20PCS A123 NEW 18650 1000-1100mah Lifepo4 battery cell - eBay (item 200496169422 end time Aug-13-10 21:02:11 PDT)
let me know what you think...
Also, it doesn't seem like you would get very much time out of just 1000mah batteries. How long do you think that it would run the amplifier?
Thanks,
Nicholas G.
In practical use I have had 20-30 hours of play time with a 7aH lead battery, but your mileage will vary depending on signal gain and speaker sensitivity.
That was why 1aH was too little for me, 4 hours play time moderate volume. Your link nicholas will provide 5aH app. which might be fine and weigh less than lead I presume. The small batteries might be more suitable for many as they are more modular and will work in many configurations.
That was why 1aH was too little for me, 4 hours play time moderate volume. Your link nicholas will provide 5aH app. which might be fine and weigh less than lead I presume. The small batteries might be more suitable for many as they are more modular and will work in many configurations.
Hey
Very nice thread. I'm sure a lot of us festival people are benefitting from this! 🙂
I have a question though. It seems like you consider anything below 100 Hz irrelevant. Does this mean that I can just disregard anything below that when designing a speaker in WinISD? I'm asking because I'm trying to design a vented box with these speakers. I'm not exactly an expert at this so...
Help would be very much appreciated. 🙂
(let me know if you need screenshots of WinISD)
Very nice thread. I'm sure a lot of us festival people are benefitting from this! 🙂
I have a question though. It seems like you consider anything below 100 Hz irrelevant. Does this mean that I can just disregard anything below that when designing a speaker in WinISD? I'm asking because I'm trying to design a vented box with these speakers. I'm not exactly an expert at this so...
- According to WinISD they require 82,7 liters pr. driver. First of all, this sounds like a lot compared to the Boominator that also uses 10" drivers. Have I put in some wrong parameters or something perhaps? It looks right when I check it. I know speakers differ but it sounds like a lot.
- Lets say I reduce the box from the 164,4 liters suggested for 2 drivers, to e.g. 50 liters. This practically only has an effect below 100 Hz, everything above almost stays the same (flat). Could I get away with doing this or should I consider other things?
- Changing the tuning freq from 50 to around 75 boosts about 3dB at 100-150 Hz. I think I read somewhere that this could be useful but should it rather be flat? Or is it a question of preference about how much bass you want?
- Should I go for a closed speaker instead?
Help would be very much appreciated. 🙂
(let me know if you need screenshots of WinISD)
I'm fairly experienced with WinISD so i thought i'd chime in. First of all, at this size you should not worry about what's under 60-70Hz. Also, your driver has a resonance frequency of 80Hz so that will limit tuning options a bit (certainly you won't be able to tune it to 50Hz or lower and drive it to high power, it'll break).
IMO too much 120-150Hz sounds just wrong, but that's up to your ears to judge. How much space do you think you'll be able to give them? I guesstimated around 35 liters internal volume, for both drivers (it still has to be portable right?). In that case a tune of 76Hz looks just about right. If you need it smaller, tune to 80-85Hz.
IMO too much 120-150Hz sounds just wrong, but that's up to your ears to judge. How much space do you think you'll be able to give them? I guesstimated around 35 liters internal volume, for both drivers (it still has to be portable right?). In that case a tune of 76Hz looks just about right. If you need it smaller, tune to 80-85Hz.
Thanks a lot, I think I understand it now. You mean 35 liters per driver, 70 liters total, right?
I meant 35 liters for everything. 😉 I have built 35 liter and 110 liter boxes, and i'd rather carry the 35 liter around. 😛 Actually the 110 liter box is gonna be a permanent install as it's inside my computer desk. 😀 Keep in mind that WinISD calculates based on INTERNAL volume, so the outside dimensions are gonna be quite a bit bigger. Remember that you also have the amp and battery inside the box taking up space.
Well, it doesn't in my opinion, outside mind you, indoors, yes certainly you wouldn't want a 120-150 Hz peak.
Hey guys
I’ve been reading through this thread 2 times now and have confidently made a mental map of what is needed to make my own Boominator. I’ve decided to make, if not a copy, then a Boominator with close resemblance to Saturnus’, which I think is rather ingenious. I’ve set my mind on a few component options and would like your opinion on some of the choices and perhaps a few advices on things to be made different.
I haven’t bought anything yet, so all components are up for discussion!
Components i’m considering:
I think I read that the AMP6Basic is running at full power all the time and the input controls the volume, is that correct? Is there a way to set a limit on output from the amp so that it doesn’t play at max even though the input is at max?
Box:
I’m planning on using an approximate design of the Saturnus boominator and keeping the basic design the same with the bipolar woofers etc, but I want to add a bit of length to the box, would it be a problem if I made it 30x30x100/110 and just added more room in the center compartment whilst keeping the other aspects the same?
In the original design Saturnus wrote that he made the handles double as the bass reflex holes, but I think he wrote somewhere that he had realized another approach was better, or did I just misunderstand something?
Phew, that was a lot of questions and considerations, hope some of you guys will take your time to answer some of it at least, so I can commence my boominator project 😀
I’ve been reading through this thread 2 times now and have confidently made a mental map of what is needed to make my own Boominator. I’ve decided to make, if not a copy, then a Boominator with close resemblance to Saturnus’, which I think is rather ingenious. I’ve set my mind on a few component options and would like your opinion on some of the choices and perhaps a few advices on things to be made different.
I haven’t bought anything yet, so all components are up for discussion!
Components i’m considering:
- Drivers x 4: HP-10W
- Alternative: Goldwood GW-1058
- I know Saturnus recommended the Goldwood if it wasn’t possible to get the HP-10W, but how much difference in quality is there?
- Alternative: Goldwood GW-1058
- Tweeters: Zomax HP800
- Alternative: Any?
- I think I read that the piezo tweeters Saturnus originally used went out of production? How are the HP800 for an alternative?
- Alternative: Any?
- Amp: AMP6Basic - Assembled
- Alternative: None
- Battery: 2 x LiFePO4 12,8V 6,8AH
- Alternative 1: 12V / 7,2AH Lead battery (Cheap)
- Alternative 2: Sealed Lead Acid 12V / 8AH
- How much better is the LiFePO4 battery compared to the others? Its almost 5 times the price of the cheap lead battery and 3-4 times the price of the SLA.
- Solar panels: 8V / 250mA / 2W
- Alternatives: Any?
- USB Car charger: Can I just buy any plug-in USB car charger and disassemble it and install it in the box?
- Cables, resistors etc: Non-decided.
I think I read that the AMP6Basic is running at full power all the time and the input controls the volume, is that correct? Is there a way to set a limit on output from the amp so that it doesn’t play at max even though the input is at max?
Box:
I’m planning on using an approximate design of the Saturnus boominator and keeping the basic design the same with the bipolar woofers etc, but I want to add a bit of length to the box, would it be a problem if I made it 30x30x100/110 and just added more room in the center compartment whilst keeping the other aspects the same?
In the original design Saturnus wrote that he made the handles double as the bass reflex holes, but I think he wrote somewhere that he had realized another approach was better, or did I just misunderstand something?
Phew, that was a lot of questions and considerations, hope some of you guys will take your time to answer some of it at least, so I can commence my boominator project 😀
Phaedras, yes, the AMP6 runs full power all the time. You just adjust the volume on the playback device or with a stereo potentiometer (not really necessary). If the volume for the speakers doesn't change, I think it's ok to change the middle compartment room, as long as it's an isolated room.
I'm working on a project using some of those components. I have 2 AMP6 Basics (made an extra just in case I fry the first) and I'm expecting some Zomax HP800's in the mail soon. For bass I'm using the Monacor SP-10A/250NEO. It's probably way too expensive if you need 4 pieces but I'm making quite a light-weight system. I'll let you know how they perform when I get the system running.
For battery I'm just using a 7Ah SLA for now. You don't really need a big car battery and it's nice to have a sealed battery. You can also always upgrade to LiFePO4 when you get everything working which is probably what I'll do.
USB Car charger: yes, you can just install it in the box and connect it directly to the battery as if it was used in a car.
Solar panel: I'm using this. I'm pretty sure it's the one Saturnus used at some point but I'm not completely sure. Will let you know when I get it up and running. I'm making a dedicated box for the solar panel as I want more versatility than just mounting it directly in the stereo.
I'm working on a project using some of those components. I have 2 AMP6 Basics (made an extra just in case I fry the first) and I'm expecting some Zomax HP800's in the mail soon. For bass I'm using the Monacor SP-10A/250NEO. It's probably way too expensive if you need 4 pieces but I'm making quite a light-weight system. I'll let you know how they perform when I get the system running.
For battery I'm just using a 7Ah SLA for now. You don't really need a big car battery and it's nice to have a sealed battery. You can also always upgrade to LiFePO4 when you get everything working which is probably what I'll do.
USB Car charger: yes, you can just install it in the box and connect it directly to the battery as if it was used in a car.
Solar panel: I'm using this. I'm pretty sure it's the one Saturnus used at some point but I'm not completely sure. Will let you know when I get it up and running. I'm making a dedicated box for the solar panel as I want more versatility than just mounting it directly in the stereo.
yes, hopefully with some time, they will, dangerous lipo and lion batteries caused numbers of regulations to be enforced pretty much worldwide, making it expensive or impossible to ship them; but as you mention, you would have to try really hard to do anything dangerous with lifepo4 and with any luck this will force a rethink on the matter. especially as they are making such inroads into the power tool and electric car realms.
I have found however, that if you send them in a shape that is unfamiliar to the masses, you wont have any problem; they dont scan or sniff the stuff, I have managed to send several devices under the radar so to speak. wouldnt try it with them on my person and with a large capacity battery though, they might arrest you under the terrorist act lol
are you guys building these things also including a dac or other source design in your builds? or are you just using a discman or ipod to feed a purely portable active speaker design?
Thanks for the reply.. I went ahead and bought a few stuff now!
So far i have ordered this:
Amp6basic assembled.
4 x HP-10W
4 x Tweeters
Alu. cabinet for amp
2 x Coil
A bit of tools; small router, soldering iron, multimeter
What kind of resistors etc would i be needing for the tweeters?
One of my parents friends is the leading supplier of veneer and some plywood in Denmark, so i'm getting some great materials from him to build the box..
I'm probably going to make the center compartment 10-20cm wider, so I can fit a few stuff in there besides battery and amp.. Im thinking about having a loose top on the box, fitted with bolts, which I can take off so its easier to access the compartment, would that give any problems with the tuning or something?
I'm not going for solar panels to begin with, i decided to start off with a small cheap SLA of around 7Ah and then expand with solarpanels, better batteries etc in a few months if I want too 🙂
I still havent quite figured out how to "tune the box" and calculate the reflex ports etc.. Any take on that?
Field test
Sorry for late feedback. But here it goes:
I left the HP-100:s running with pink noise for at least 40h before heading of to Roskilde. My conclusion is that they definitely changed character to the better, sounding more "natural". However, I still think that they are to "soft" and lacking that last "hi-end" treble (that might be impossible to achieve with piezos though...).
Field test report:
I'm really happy with the performance of the Boominator @ this years Roskilde festival! It sounded great and was fairly easy to carry around late nights. Thanks to the aluminum edges and the round metal corners it also became virtually indestructible.
I also added a uC-controlled giant LED VU-meter (using audio as input) on the backside which attracted even more people to the dance parties at the camp 🙂
YouTube - Boombox with built in VU-meter
Battery life was excellent. I used two 7.2Ah SLA:s (not at the same time though) and charged them during the day with a 20W solarpanel from solarlab.se.
Sorry for late feedback. But here it goes:
I left the HP-100:s running with pink noise for at least 40h before heading of to Roskilde. My conclusion is that they definitely changed character to the better, sounding more "natural". However, I still think that they are to "soft" and lacking that last "hi-end" treble (that might be impossible to achieve with piezos though...).
Field test report:
I'm really happy with the performance of the Boominator @ this years Roskilde festival! It sounded great and was fairly easy to carry around late nights. Thanks to the aluminum edges and the round metal corners it also became virtually indestructible.
I also added a uC-controlled giant LED VU-meter (using audio as input) on the backside which attracted even more people to the dance parties at the camp 🙂
YouTube - Boombox with built in VU-meter
Battery life was excellent. I used two 7.2Ah SLA:s (not at the same time though) and charged them during the day with a 20W solarpanel from solarlab.se.