Instructables

Super portable, super loud, long lasting, battery powered speakers

Featured
Picture of super portable, super loud, long lasting, battery powered speakers
ever wanted to have a powerful speaker system for those inpromtue garden parties/field raves. many will say this is a redundant Instructable, as there are many boombox style radios from days gone by cheaply available, or these cheap ipod style mp3 docking stations that run on batteries.
I strongly disagree with this statement, boomboxes are huge and eat batteries, docking stations are weak and sound poor. so for the best of both worlds, I present to you my portable rave speakers.

I built these speakers to meet these specifications:

-compact, for easy, in a back pack transport
-powerful, for punchy clear audio to get those outdoors raves going
-long run time, who wants to stop raving ?
 
Remove these adsRemove these ads by Signing Up

Step 1:

Picture of
First step as always is, what do you need?

Components:
-speaker cones (take them out of a couple of sets of computer speakers)
-amplifier chip (see next step for details)
-1Mohm potentiometer
-3.5mm audio jack
-2 * 470nf capacitors
- a 220 micro F capacitor
-2 5kohm resistors
-high capacity set of batteries (12-18v 4000mah+)
-the best heatsink you gan get

tools:
-soldering iron
-dremel (or equivalent)
-wire cutters

Other materials:
-lots of assorted shrink tubing (electrical insulation)
-solder
-small project box (altiods tin would suffice)
-a good length of good quality wire.
-battery connectors of choice (I chose deans "t" connectors)
-thermal greese
1-40 of 98Next »
yaly3 months ago

I made one with two TDA2003 and overpowered it with 15v, it gave me ~13W RMS x2 into a pair of blaupunkt speakers. Try the TDA2003s, AWESOME \m/

kkuxer yaly2 months ago
I think, that it is better to use TDA2005)
M0DC3T5 months ago

Is it passible to use 150W speakers with TDA7057AQ?

I'm using the next components:

1x Capicitor: 220µF 10v220µF

2x Capicitor: µ47k63

1x Potmeter 6MM AS 1M

1x Female jack 3,5mm

2x 4.7 Kohms, +/-5%

1x HQ Sealed Rechargeable battery 12V5Ah/20hr

Roarax8 months ago
in the components needed you say a 4000mah+ battery but in the photo you use a 2250 mah battery. will the one you use still work?
ASCAS8 months ago
Awesome project! You might want to try the class-T amplifiers. They will extend you battery life up to 5x.
Just a note if you really want super loud maybe upgrade on the speakers. I built something similar in a pelican case marine grade polk speakers and a rockford punch 30 amp. This thing is LOUD. Powered by a 20aH sla. Runs all night when fully charged. Wish i had your battery setup as mine is heavy.
what would happen if you added two amplifiers, instead of one?
The end of the world would happen. That's what.
ravenhaker2 years ago
You me at six?
xcmer2 years ago
Very nice tutorial. Being a complete newb to this, I have a few questions, if you will.
I have a set of 2 2.7Ohm speakers (with two tiny tweeter disc things attached in parallel) gotten out of a boombox. The label on the boombox itself says 50W.
I'm planning on disposing of the (broken) Boombox and making a new one out of a briefcase, but aside from scaling up to a suitable amplifier chip, how much higher capacitors/resistors/potentiometer should i use?

Thank you!
xcmer xcmer2 years ago
Nevermind- I just realized it's all in the data sheet. Didn't read closely enough.
maxhysteria3 years ago
actually when you connect a pair of speakers in series, instead of raising the ohm load, like you said from 4 to 8, you will actually drop the ohm load, so it would be 2 ohms instead of 8. now if you dont believe me, just google it or look it up on youtube. if you were to have connected the speakers in parallel, you could potentially have even louder rave speakers that will last longer because less power is required to run them. Awesome project though man, this is probably the coolest boom box project ive seen on the website!
@maxhysteria, actualy you might want to google it... series wiring ADDS ohm load, not decrease. 4ohms x2 in series is 8ohms as he stated. Series wiring is positive to negative like batteries in a flashlight, stack them up then add them up.
polop (author)  jdread3 years ago
@maxhysteria indeed jdread is right, I think you have mixed a few facts up, series connected impedances add, also in general the lower the impedance connected to an amplifier the louder the speaker will be (more complicated than this really) but the power drawn will be proportional to the output power of the speakers, hence the batteries will run out quicker. Any way you can ask if you want a real analysis of the situation.
T0C polop3 years ago
Why argue, if not sure just measure with a multimeter or other device. And another thing about the ohms, the higher they are, the lower the consumption and the smaller the heatsink has to be, if they are lower it's the opposite, higher power consumption, louder amp, bigger heatsink is needed...
sconner1 T0C2 years ago
In series, the speaker impedances are added and the power use goes down because of Ohms Law.
In parallel, the impedance is half (as long as the two speakers are the same) and the power use goes up for the same reason.
The tradeoff is loudness vs. battery life.
Up to the point of the chip's and battery's minimum load and maximum current capabilities.
Too low of an impedance will:
If you're lucky, put the chip into protect mode
If you're not, fry the chip with too much current even with a proper heatsink OR
the battery won't be able to deliver current fast enough and cause "clipping" where the audio waves can't be reproduced properly and you get distortion.
Electric guitarists often want this effect but for music playback, it's ugly and causes ear fatigue.
bengström T0C3 years ago
When it comes to speakers it not that simple.
The resistance (impedance)varies depending on which frequency feeding the speaker, the resistance value is measured at 1kHz(?, not entirely sure).
polop (author)  bengström3 years ago
@TOC Don't worry this isn't an argument, just a discussion. Like Bengstr?m said there are more complicate forces at work and in general you should be absolutely sure what you are doing before you use a multimeter, in general an 8 ohm speaker has roughly 6.5ohm D.C resistance, but the impedance can only be properly described by the impedance curve of the particular speaker (impedance vs. frequency, can be done with a multimeter and a signal generator, but you might miss some important details) at resonance the impedance can be really quite high. But in the end none of this matters for this kind of instructable - it is meant to be quick and dirty way to get portable audio, using nominal impedance is fine for matching speakers to amplifiers. At some point I will upload a real instructable that goes into these details - leading to a truly high quality product.
T0C polop3 years ago
I didn't say that when you measure it with the multimeter you would get an accurate reading, i was supposed to say "if you don't know it measure it with that and you would roughly get the impedance." also nice Instructable.


Btw i'm also working on a portable amp or two, and in about a week or so i'll post my design as well. (it isn't very big, but weighs about 2-3 KG with speakers that's it's only disadvantage... The good thing is it lasts about 1-2 days on full power non stop playing and it's 2x10 W ...)
polop (author)  T0C2 years ago
2-3 kg that is bretty good going, my new speakers weigh around 4kg, and have 72Wh of energy stored, or 3.5 hours at 2*10W.

I think you are likely to be missing some information some where (look at my very long post to someone about output power) according to you, I will be generous and 24 hours at 2*10W. this means you have 480Wh of stored energy. If you are using lead acid batteries that would weigh (480Wh) /(41wh/Kg) =11.7kg, that's a big battery.

If you used a good lithium ion battery (480Wh)/(128Wh/Kg)= 3.75 kg (this would be quite expensive)

That is just battery weight, plus cones and enclosure a speaker that could last even just one day at that power would weigh at least 5kg if you are incredibly clever about reducing weight. 2 days - obviously allot more than that. So you are likely over estimating the power you are actually using and probably the time that they will last as well. If your speakers do actually weigh 2-3kg and contain more than 480Wh of energy - call the patent office now - because you are going to be a rich person. ;p


T0C polop2 years ago
Here's a short explanation:

That post was made 4 months ago, the amp from then is long dead (It could play about 17h or so on a full charge (on full power around 12h.)
The weight of the amp and speakers was >500g (good ol' AlNiCo magnet speakers) the rest of the weight was the battery (and case, tho the case couldn't have been more than 200g)
So, the 17h run was made with old cell-phone(look like cell phone batteries, but i don't think they are) batteries (nothing beats good ol' industrial batteries, the ones i used were 4.2V ~2110mAh (don't ask where i got them from) ) a total of 15 (...) batteries were used (and are still in use).
From what i calculated the brick was around 10Ah 12-13V
(Also, don't start calculating weight and stuff, these are not ordinary li-ion batteries they're Russian li-ion batteries, lol)

Also the weirdest thing was the batteries were(are) as light as a feather. If you took 3 batteries from these they would weigh as much as a BL-5C battery (aka the battery EVERY NOKIA phone uses today) don't have a good thing to compare to.


One last thing, the amp. I don't exactly remember it ( there were a lot of modifications to it), but from what i remember it was transistor based (when i say transistor based i mean it had a lot of bipolar and FETs) and was almost as big as the box, the output power was around 2x4-5W (10W speakers) it took 4 books and a lot of stupidity to make, but the end results were insane around 0.00042% THD made the sound crystal clear ....


That's all i remember
ask away if you have any questions.
polop (author)  T0C2 years ago
The no ordinary battery? if they are production batteries (cell phone) they will not have met your original specs any-day (even prototype batteries struggle to get over 200Wh/Kg) any way I am not trolling, but you shouldn't trust cell phone grade batteries ratings, especially if the source is dodgy. They are rated at very low draw and are overrated deliberately to outsell others (though I am sure the Russians are not as bad as the Chinese for that one, I have seen some Chinese products that break the laws of physics for only a few dollars :P)

About the amplifier - I would be interested in seeing the schematic/source of that - never have I seen a distortion figure that low for a practical audio amplifier. That is at least an order of magnitude better than ones I can find on the internet. Did you measure the distortion characteristics? or are you guessing ?

The case, less than 200g, was it made of cardboard? on my newest speakers my case weighs around 1Kg and it is too flimsy (partially my lack of skill I am sure, but I would think 1/5th of the weight would be horrific :P)

What size speakers were you using, 500g for 2 would be limiting you to some quite small ones, a decent single 4" driver is about 1kg (750g would be a little skimpy). if they are much smaller bass is going to go out of the window (especially if the box is not rigid enough).

anyway I would be interested in your answers from the sound of it you might have an interesting setup :)


T0C polop2 years ago
About the battery, I just remembered they weren't from cell phones but were from a CPU(no idea what it means but its really cool)(Don't know the translation but it's a gigantic, not so old, CNC like machine).

The case is made from a plastic-like substance(a friend gave it to me, but it got lost about 1 month ago....damn...)

The speakers were small, yet powerful, not sure bout the dimensions and i think they were about 10W each... They're full range speakers with awesome highs and pretty clear lows (but when you run everything from one speaker sometimes the bass craps up the highs a little) also they're not that light one is about 300g, wasn't thinking when i wrote 500g overall.... pic related.


The amp, Actually me and a friend from Resprom(a Bulgarian audio company that made some of the best sounding amps and speakers I've ever heard.) developed/build the amp. He made most of the amp I just helped with the output stage(fun thing is after i made the output stage the dude gave me some weird looking transistors that turned out to be pretty fast/powerful) and filter.
Also he measured the THD with something like an oscilloscope.
All i remember from the schematic is....hmm.......well nothing.

Twas a great amp.
IMG_3759.jpgIMG_3760.jpg
Great job!
I can see that you are very ambitious, so if you wanna build some much more louder BOOMBOXES i can send you all the shematics, i have done some of it and when i came to school even the profesors were impressed how loud and how clear it was and how simple the amplifier was. It has 2*45Watts RMS on 12V battery. You can check the datasheet of IC it is called TDA7375A that one is stereo version, if you want to go quad there is TDA7386 i reccomend these two they are very simple to build and the quality of sound is amazing.
BTW. Sorry if my english is bad because im from Croatia.
polop (author)  mhermeščec2 years ago
HI there, indeed I am very ambitious! as you can see this instructable is nearly 2.5 years old. Since this publication I have moved onto some interesting things. The amplifier that you linked to is indeed a very good simple option, I guess it is cheap as well. you need to be careful reading looking at the output power ratings, indeed it can output 45W per channel on a 12v battery (14.4v completely full), but it would sound very bad. This is because that rating is given at 10% distortion using a square wave (ie not really music :p). If you look into the issue a bit more (have a look at page 7/14 on the data sheet, on the THD% vs Pout graph for 14.4V vin - BTL into 4ohm) you will see that actually using the highest battery voltage into 4ohm speakers will only give you around 15W before the distortion (THD%) starts to go up very quickly. When it gets to about 0.1% it is time to give up if you are wanting the best quality sound. Then of course 2* 15W is very loud really (as I am sure you have witnessed first hand with your speakers).
So everybody is happy - apart from your battery, and this is where the class of amplifier you are using lets you down. Yours is a class A/B. There is lots of information around about what that specifically means but the issue is that this class of chip usually uses more power than is necessary when there is no output (actually it is much better than a lot of classes). Yours uses around 150mA just sitting there, or 2.16W (0.15A * 14.4V) that is allot of power not doing anything useful to us. Seeing as a major component of music is silence in-between sounds or low level sounds (in between bass thumps for example). So where am I going with this? is there a more efficient amplifier that is clearer? of course there is otherwise I wouldn't have written such a long post. Look at this amplifier http://shop.41hz.com/shop/item.asp?catid=42&itemid=43 . The output power at comparable distortion is the same as your amplifier but the power drawn quiescently (no sound) is much lower (64mA*13.4V = 0.86W) and in fact the measurement on my sample is actually 0.5W. so this is around 4 times the efficiency of yours when there is no sound, this matters less and less as you put the power up - at maximum power (15W if you want it to sound nice) there is little difference I expect, but the AMP6 will sound clearer generally. So if you find you use your speakers for BBQs/just chilling allot (rather than booming and raving) I would recommend you use an AMP6. If however you are using it exclusively for raving I would advise buying two Amp6's or one AMP9 and building the speakers in the style of http://www.diyaudio.com/forums/class-d/104402-boominator-another-stab-ultimate-party-machine.html . That link is probably to the most professional DIY boombox on the net. sorry for the very long post - hopefully we can inspire each other:)
thanx for the idea, an i agree with you for the power consumption, but the sound ist that disorted even on the loudest setting if the speakers can handle it and since i dont have much money this option was more suitable for me
emazinboi4 years ago
what are the batteries??
i need to know so i can get some :]
polop (author)  emazinboi2 years ago
Hobbycity.com has B grade lipos that are cheap and good - plus sorry for the late reply :P
ebay has many such batteries and chargers.
mhine0221103 years ago
I cannot understand the schematic you gave. Please give a more understandable schematic. I'm sorry but I'm just a beginner.
Personally, I've seen very few schematics in my short life; but this is a very simple wiring diagram and if it is beyond your understanding, you should do some reading on electronics else you'll probably kill someone
polop (author)  shock8x2 years ago
Yes I don't think it can be much more simple really, I am not a fan of the whole "picture based schematic" take your time to read into it and you will be fine.
I'm just going to suggest buying a "class T" amp from eBay. As cheap as $12 shipping included, and all you have to add is the volume control. Very efficient, yet capable of over 10 real watts into 4 ohms. If you want to go fancy, $20 gets you an amp in a case with knobs, ready to bolt on. Search on TA2020 or TA2024 and amplifier.

And, don't overlook scrapped CRT TVs as a source of speakers. Also, if you're a real scrounger, an amplifier: on one Sony I found in the woods, the audio amp chip was on a corner of the circuit board and I was able to break off that section with my bare hands.
polop (author)  bassbindevil3 years ago
ebay amplifiers are all well and good, I have tinkered in the past, they don't really cut it compared to "the real deal" from 41hz, nor will rescued speakers preform aswell as speakers with accurate data sheets with well defined values, also speakers that other [people have used are a good place to start. This instructable is a little out of date with my audio beliefs now. for me 41hz amplifier HiFi speakers and lithium polymer bateries are a match made in heaven. some of my more recent creations are attached
DSC00408.JPGDSC00454.JPG
OK. Well, I was going by what was presented here, which was a linear chip amp and random speakers, apparently without either baffles or stuffing. (Baffles prevent the bass frequencies from the front and rear of the speaker cancelling each other out. Stuffing suppresses internal box resonances so the midrange doesn't honk, and also makes the box behave as if it were larger at bass frequencies.) Hifi speakers are obviously better, and can often be found for crazy prices at yard sales and thrift stores (Energy, $6 a pair, Minimus 7, $10 a pair). If someone wants "loud", look at using smallish pro audio midwoofers, like 8" to 10" Eminence Alpha or Betas, or some (hopefully) comparable (cheaper, anyway) MCM Audio Select. A somewhat larger cabinet will be required but higher efficiency and deeper bass should be worth it.

I suggested a T-amp because if you order a TDA7057AQ from someplace, it'll cost almost as much as one of the TDA2024 amp boards. And the TDA7057AQ doesn't appear to be rated to drive 4 ohm loads, which limits the choice of speakers and means that 2 per side (as shown) may not be a good idea.
polop (author)  bassbindevil2 years ago
I agree, If you are in Europe (which is unlikely due to the use of $) go to 41hz.com and buy an amp6 - cost more than $4 but definitely worth it if in the US you can get the class T amplifiers pre-assembled on ebay (but they won't be as good as a high quality kit - due to the cost cutting Chinese-ness ) then use some 4" hifi full range speakers (if you want compact) or like above some pro-audio 8" in a nice box and the musical world is your oyster!
sjoobbani polop2 years ago
Old car amps work well too! i got two mono amps, very small, very simple, very HQ for $4, I use it in my DJ set up for lights haha
kalopsy2 years ago
Great job bro!
Im kinda n00b to building speakers and thought you could help me with it...
I have two 4watt, 4Ω speaker elements and want the build a portable speaker/boombox.
If you consider helping me I'll make sure your name will be written on the front of it. :D
So basicly i want a list of components, and a "blueprint".
I would appreciate it alot!
excuse me for bad english, im from sweden.
polop (author)  kalopsy2 years ago
Hello there, If you want the very best sound quality you really need to know the particular specifications of the speakers that you are using, then you can do some maths to find out the best volume for the box (to maximise BASS and VOLUME!! we all want that) but in general if this is your first go at speakers don't worry about that too much, just make sure that the speakers that you have are full range (not tweeters) find a small amplifier chip (probably the one I used in this instructable would be good) make the circuit and test it. then cut holes in a nice rigid box, toolbox maybe, the best would be if you could make a simple wooden box. Attach the speakers and the amplifier and a small 12V battery and It will sound like heaven (mainly because you made it). Then as you get better at looking at the maths - perhaps have enough money to buy some more serious speaker drivers and a better amplifier, you can make much more professional speakers. My main advice is just to start doing it and let the DIY bug help you along to make the project better in the future. This instructable was my first attempt at building speakers, very simple - lots of mistakes, but mistakes make you learn, and from these speakers I learned allot :P Now I am making speakers at a much more professional level, just get stuck in and get going and you will have great fun.
polop (author)  polop2 years ago
actually you would have to find a similar amplifier that can handle 4ohms properly, there are lots around though:)
1-40 of 98Next »