Picture of Off-Grid Party Sound Systems
Whether its for a mobile bike party or a solar powered concert, a 12V or 24V sound system is the key.  I recently built several systems for mobile bike parties and this article has a pile of details.  You can also check my Easy Bike Party Sound System project if you want a simpler and smaller system and my Bike Party Sound Trailer for specific tips on a trailer design.  If you want to just purchase finished speakers built according to the principles of this guide, we sell them at MonkeyLectric.

This article covers:
  • A simple but efficient setup where you just pick the right parts and plug it together
  • A true Active 12V speaker - an ultra-efficient speaker with integrated 12V or 24V internal amp.
  • Choosing efficient speakers and amps
  • Choosing a battery
  • Weatherproofing and vibration proofing
The goal of this project is to achieve sound levels needed for off-grid dance parties while reducing weight and power use.  Compared to common setups, we achieved power reduction of 50-80% and weight reduction of 20-40% with equivalent sound output.

My friend Deep runs Flashdance, and we used his system as a reference point to compare our work against.  Deep has an amazing tricycle setup that lets him bring the party wherever he goes.  San Francisco has rather notorious hills though, so our goal was to see if we could cut the weight of his setup without sacrificing any of the sound.  A big key to cutting the weight is to see if we can use something much smaller than a car battery - and that means being more efficient about power use.

This project is brought to you by MonkeyLectric and the Monkey Light bike light

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Step 1: A word about Efficiency

Picture of A word about Efficiency
The key to any battery-powered sound system is efficiency.  Home and car sound gear is not designed to be efficient or light - it just isn't a concern in those applications.  Low efficiency means you need lots of power to make the same amount of sound, and lots of power means a big heavy amp, a big heavy car battery, and maybe a big heavy inverter too.  An efficient speaker can produce 5x the volume from the same amount of power.  An efficient amplifier is 2x better than a standard one, plus its far smaller and lighter.  Together this means that with a bit of attention paid to your component choices, you'll get way more output for the same amount of power.

Lets take a look at Deep's current system.  He's got:
  • 2 nice Yamaha powered speakers (they have a built-in amplifier)
  • An inverter because the Yamaha's need 120V
  • A car battery
Another option I see some people using goes like this:
  • 2 big auto-sound speakers
  • a big auto amplifier
  • a car battery
Either way there is a lot of inefficiency.  Using 120V powered speakers, the amp inside the speakers is moderately efficient (not the best, not the worst).  we lose a good chunk of efficiency because of the inverter.

With auto-sound gear, you don't need an inverter but the problem is that it all the parts have very poor efficiency.  I think this is due to marketing forces at work - the folks selling you this stuff learned that if the amp and speakers are bigger and have higher watt ratings, they make more money selling them.  but, those high watt ratings are only needed because the gear is so inefficient.

Step 2: Efficient speakers

Picture of Efficient speakers
PA, DJ and "Live Sound" speakers are the best place to look for efficiency.  You will find the efficiency measured as "SPL 1w/1m" in the spec sheets of most speakers.  "SPL max" is different.  Every 3 points of SPL means DOUBLE the efficiency: 90 is bad, 96+ is good. 

Large speakers (both boxes and driver cone size) are nearly always more efficient than small ones.  If you don't care so much about the weight get the biggest speakers (15" or larger woofers).  If you do care, the weight and size of the speaker will be your main tradeoff in your setup

Think about going MONO!  Stereo doesn't always make a lot of sense in an informal environment.  Using one larger speaker you will have overall higher efficiency and lower weight than two smaller ones.

I built and tested systems using the speakers listed below.  All but the smallest are rated SPL between 95 and 98:
  • Behringer S1020 - 10" woofer, 20 lbs, $100
  • Behringer B212XL - 12" woofer, 25 lbs, $170
  • Pyle PPHP121 - 12" woofer, 30 lbs, $120
  • Peavey PR12N - 12" woofer, 25 lbs, $180
  • Peavey PR15N - 15" woofer, 32 lbs, $220
  • Gemini RS-308 - 8" woofer, 15 lbs, $70
We also compared against Deep's original Yamaha MSR250, which are pricey and average 27 lbs each.

Our tested results for these speakers:  The Peavey and Pyle are the loudest with the same power input, and about equal to each other.  The Behringer's are noticeably less loud.  The B212XL and the Yamaha have noticeably better audio quality than the others.  (more results later).  The Gemini is by far the smallest speaker here - it will fit into a milk crate - its not as loud as the bigger ones but great for its size.

Bigger speakers (15" or 18" woofer) can get up to 100 or 101 SPL efficiency.  With more expensive speakers you can find something a little more efficient, but mostly you are buying higher sound quality and a higher maximum power level.  Running off batteries you likely will be well below the maximum power levels.

Where to find this stuff:
  American Musical
and others...  (amazon.com has some of them)

Step 3: Efficient amplifiers

Picture of Efficient amplifiers
For amplifiers there is really only one choice: a Tripath-based amp, sometimes called a T-amp, Class-T amp, or Digital amp.  These ultra-efficient wonders are inexpensive but obscure.

(a note on terms:  "Class-T" is a marketing term.  All T-amps are technically "Class-D" amps, sometimes refrerred to as "Digital" amps. There exist non-Tripath class-D amps, but all the ones I have seen are either very small or only for use with subwoofers (they are not "full spectrum").

T-amps are available in a couple of different sizes, based on different amp chips:
  • TA2024 based amps: 10 watts per channel, runs on 8V to 16V DC
  • TA2020 based amps: 20 watts per channel, runs on 8V to 16V DC
  • TK2050 based amps: 100 watts per channel, runs on 8V to 36V DC (needs 24V for full power rating)
  • TA2022 based amps: 100 watts per channel, requires custom power supply
Those are the most common models i currently see available for purchase.  Most of the ones I can find are only sold direct from Chinese vendors through Ebay.  This means they are cheap, but it will take 2 weeks to get it.  Please post if you know of other sources for these amps.

I bought and tested several of the common amps I found on ebay.  Note that there are many vendors on ebay all selling the same amps (or copies of the same amps).  The names of the amps get a bit confusing, its easier to go by the photos.

How to find these on ebay.com:  search for the amp chip:  TA2020, etc.  You will find tons of these amps.

Stand alone amps (amps with a plastic or metal case):
  • SMALL: Dayton DTA-1 from parts-express.com, $45.  TA2024 based.    This amp includes a built-in battery holder.  It runs at full power for 3-5 hours on 8 rechargeable AA's.  If you want a small system, this amp is really convenient and recommended.
  • MEDIUM: "SMSL" or "Topping" type TA2020 amp - $20 - I bought one from ebay seller indeed-hi-fi-lab. This amp is very good quality with durable construction, and sounds great. It also has a small and attractive case. indeed-hi-fi-lab seems to have 2 variations called the "Tripath TA2020 Mini Cute Class T Amp Amplifier Ipod MP3" and the "NEW Class T Amp TA2020 Amplifier Tripath Chip TA 2020". Rest assured mine is the "mini cute" type, but the other one looks equally well made in their photos.
  • LARGE: Dayton DTA-100a from parts-express.com, $95.  TK2050 based.  This is a 24V amp and includes a wall wart.
  • BAD:  "Lepai" TA2020 amp from ebay seller "box-them", $20. The internal construction of this amp is low quality. It also broke after a few days use so - NOT RECOMMENDED - particularly as there are better options for about the same price.
Bare board amps (no case included):
  • BIG:  "TK2050" and "TK2050-improved" amps - $40 - from ebay seller sureelectronics. The "improved" version is now available from parts-express.com also.   These are "bare board" amps without a case. I built several sound systems using these amps.  Note that you MUST use a powered mixer (see later step about this) to to get full power out of these, but even so these are the best deal going for a high power setup.
  • MEDIUM:  "MKII TA2020" and "MKIII TA2020" amps - $25 to $35 - from ebay seller arjenhelder_electronic.  These amps are top quality and sound great.  These are "bare board" amps with no case.  They also come with bare wires for power and audio input, so you'll have to do some soldering to hook them up.  These also need some vibration-proofing if you plan to use them on a bike.

Step 4: Notes on the Sure Electronics TK2050 100W amps

Picture of notes on the Sure Electronics TK2050 100W amps
I got 2 different TK2050 amps from Sure Electronics - their original 100W system and the "improved" 100W system.  These are both "bare board" amps.  At $40-$50 for a 2x100W amp with 85%+ efficiency, these are amazing deals under any circumstances.   I recommend the "improved" amp because its umm - improved!   ok here's the deal:
  • With the original amp you must use a powered mixer (see next step) to boost the levels from the mp3 player.  If you don't, you will get at best 5% of the rated output.
  • With the improved amp, you can get about 25% of rated output plugging your mp3 directly to the amp.  This isn't bad, but you still need to use a powered mixer to get full output (see next step).
  • Another note about the "improved" amp: it has a small heatsink with a fan. I'm not a big fan of fans, because they are failure prone in dirty or vibratory environments. I've been using this amp inside a speaker and letting the airflow from the woofer cool the amp - this means i can chop out that fan.
The technical details:
  • The original amp has "low input sensitivity".  This is a fancy way of saying that it has no volume knob, and the volume is pre-set at "low".  Kinda dumb.  If you try to power it from an mp3 player, the maximum volume on the mp3 player won't run the amp close to its designed power level.  If you are handy with a soldering iron, this volume problem is easily fixed by replacing 2 resistors.  If not, you need the powered mixer.
  • The "improved" amp improves the volume problem - it has a set of switches on board that let you choose the desired volume (3 choices).  Even the highest setting won't get you to full power with an mp3 player, but at least its usable. 
If you want to hack your original amp to change its volume setting, check the photos:

Step 5: Mixers

Picture of Mixers
If you want to have a microphone or any 2nd input in addition to your mp3 player then you need a powered mixer.   Also, the higher-power 100W amplifiers need a powered mixer just to boost the signal level from the mp3 player.  Without the signal boost you just can't get maximum volume out of the amp.

There are a couple of different suitable mixers available around $50.  I've been using the Rolls MX51s, which calls itself a "stereo powered mini line mixer".  you can get it from parts-express.com, amazon, and others.  there are some other brands with nearly identical products.

How to use the mixer:  
  • the mixer sits between your inputs (mp3 player, mic) and your output (amplifier).  plug your mp3 player and mic into the 'input' jacks on the mixer.  
  • plug the 'output' jack on the mixer to the input of your amplifier.  
  • The mixer also needs DC power, most models like the Rolls have a wall-wart but run on DC power internally - 9V and 12V are common.
  • The Rolls runs on 12V internally, which is very convenient for our battery-powered setup.  I just cut the wall wart off the power cord that came with it and wired it straight to my 12V battery.
  • You must connect the ground wires between the amp and the mixer, or you will get hum or even damage the amp.  With a 12V system this is easy, the amp and mixer should run from the same 12V battery.
  • If you are building a 24V system: check the wiring diagram below.

Step 6: Power, Batteries and Chargers

Picture of Power, Batteries and Chargers
for the smaller TA2024 and TA2020 amps, a 12V battery is needed.  To get full power from a big TK2050 amp you need 24V, although it is possible to run the amp on 12V at reduced power.

12V SLA batteries (also known as "gel cell" or "sealed lead acid") are very convenient for a battery-based sound system.  They come in many sizes and are inexpensive.  If you need 24V, just get two 12V batteries and wire them in series.  SLA batteries are widely used in electric scooters, emergency exit lights, "UPS" computer back-up power supplies, etc.

Free batteries!  You can often find SLA batteries free at your local recycle center.  I've found that the UPS systems are often disposed while the battery inside them is still in good condition and easily removed. 

If you want to just buy a new 12V SLA battery, they run $20 to $45 depending on the size.  Amazon.com and batterywholesale.com  have many sizes, just search for "12v sealed lead acid battery".  

For a TA2024 or TA2020 system, you can also run on 8 or 10 AA batteries. Use rechargeables since it will last 3 to 5 hours. You can get a 10-AA battery holder from mouser.com part number 12BH310. 

Capacity:  SLA batteries come in a wide range of capacities.  For a smaller systems a 4Ah to 8Ah battery is good and will be 3 to 6 pounds in weight.  Figure on 1 to 2 hours runtime per Ah with a smaller amp.  For a larger system or multiple speakers, you probably want to think about how long you need to run your setup for as compared to any weight consideration.  With my setup I have 9Ah batteries for a single TK2050 amp, and 18Ah batteries for a dual-speaker setup, both of those will run for 6 or 8 hours at full volume, all day if i turn it down just a little.  A standard car battery is around 50Ah.  rechargeable AA's are about 2.5Ah capacity.
Charging:  12V SLA batteries can be charged with a small car battery charger, you can also get small and inexpensive chargers designed specially for them.  Many electric scooters run on 12V, 24V or 36V, so conveniently you can find $10 to $15 chargers with all 3 of these voltage choices. You can get these $10 scooter chargers at Amazon, just search for "12V SLA charger" or "24V SLA charger" or "36V SLA charger".  They come with a connector that you can just cut off and replace with crimp-terminals.
Weight:  gel cells are heavy, but you'll still save a lot of weight compared to a car battery just because your setup is efficient so you won't need as big a battery.  A car battery is 40 or 50 lbs, and my gel cell is half that weight and powers an equally loud setup.  Lithium packs are the lightest, but much more expensive than SLA.  You can get some good big lithium packs from all-battery.com.

Step 7: The Elements

Picture of The Elements
Depending on your application, you may want to improve the waterproofing or vibration proofing of your gear.

Waterproofing - if you are re-cycling a home audio speaker, you probably want to paint it.  a PA or DJ speaker normally has a waterproof box.  In either case, i found the woofer cone is often made of unprotected stiff paper.  You can easily waterproof this by coating it with a thin layer of a water-based urethane wood finish - such as Varthane - from your home improvement store.

Vibration proofing - i'm making mobile bike systems, these get vibrated a lot.  amps often have some larger components in them that may or may not be well attached to the amp board.  take a look and glue down anything that looks flimsy.  hot-melt glue and silicone glue both work well to glue down any wobbly parts in your electronics.  some of the T-amps are ok.  the ones from arjenhelder_electronics needed some anti-vibration glue (see the photo).  the original TK2050 from sure electronics also needed a bit of help.

Step 8: Just do it now!!

Picture of Just do it now!!
ok there's an easy way and a hard way for everything.  If you want the easy way, here it is:

read the previous steps.  get an efficient speaker (or 2), get an effiicient amp, a battery, and plug them together.  done!!

(my article about a simple rear-rack mounted bike party sound system shows an example of the 'do it now' option)

the steps after this show how to make an Active 12V speaker - a speaker with integrated battery-powered amp.  This allows slightly improved efficiency, lower weight and a more convenient package, but it is also more complex to build.

Step 9: The fully integrated Active 12V-24V speaker

Picture of The fully integrated Active 12V-24V speaker
Along my quest for speaker efficiency I started thinking about Active speakers (also called Powered speakers).  This is the term for when the amp is built into the speaker.  Most active speakers are built for 120V wall power - it means you just plug in your active speaker and plug the mp3 player straight to it.  very convenient. 

I looked around for a while for an active 12V speaker - one with an integrated 12V amp - but there's really not much out there.  just a few subwoofers for cars, nothing full range.  so lets make one!  the benefits:
  • with the 12V amp inside the speaker, you have a convenient integrated package, plus you save the weight of an extra box and wires.
  • with the amp wired inside the speaker, you can wire individually to the tweeter and the woofer.  this allows additional efficiency improvements.  lets explain:
the nitty gritty:
inside your speaker are normally 2 or 3 "drivers" - the things that make the sound.  the low-frequencies are made by the big cone, called the woofer.  the highs are made by a smaller horn called the tweeter.  sometimes there's a 3rd midrange speaker.  the efficiency of each of the 2 or 3 drivers is not the same.  in a PA/DJ speaker the woofer might have a 96 SPL rating, while the tweeter might be around 103.  that's a big difference!  when you have your amp outside the speaker (as in any home or car stereo setup), there is just 1 signal sent to the speaker.  inside every speaker is a "crossover" circuit that splits the sound up - it sends the low frequency part of the sound to the woofer and the high frequency part to the tweeter.  just doing this at all incurs perhaps a 5% or 10% efficiency loss.  But - what if the tweeter is much more efficient than the woofer?  if all the crossover did was split up the sound, then the efficient tweeter would play all the high-pitch sounds way too loud compared to the low-pitch sounds played by the less efficient woofer.  so the crossover has a 2nd job - it equalizes the sound by reducing the volume on the tweeter.  but, the way that this volume adjustment happens in the crossover is by blowing off the excess power as heat - another efficiency loss.  in an active speaker we have the opportunity to fix this - active speakers use a separate amp for each driver - one amp for the woofer and one for the tweeter, and we can just turn down the volume on the tweeter's amp.  that's an efficient way to reduce the tweeter volume instead of the inefficient way the crossover does it.  Since our T-amps are so cheap, this also won't cost much to do, and we'll end up with our amp neatly mounted inside our speaker.

Step 10: What you need

Picture of What you need
to make the fully integrated 12V amp + speaker, you need:

- speaker
- stereo amp
- crossover

Check the system diagrams below.

When the crossover comes after the amp, then it has to be big to handle the full amplified signal, and it has to waste power to equalize the tweeter and woofer volume.  But, we always need to split apart the highs and lows from the mp3 player and direct them to the tweeter and woofer.  So the secret to a good integrated amp setup is that we put a small crossover BEFORE the amp.  this gives us an un-amplified tweeter signal, and an un-amplified woofer signal.  we route one of those to the left channel input of the amp, and the other to the right channel input of the amp.  Then on the amp output side we wire the left channel direct to the tweeter, and the right channel direct to the woofer.

When we put the crossover before the amp, we can also use it to adjust the volumes of the tweeter and woofer, and also to combine stereo to mono if we want to.  operating on the un-amplified signal these can all be done without power waste.

So, to make the integrated 12V amp + speaker you need:

- speaker(s)
- 1 stereo amp per speaker
- 1 crossover per speaker

The stereo amp can be whichever T-amp you like.  My build photos mostly show the TK2050 amps.

The crossover - I made my own circuit for this - see my monoXover project.  It is a fairly simple circuit so you can build it yourself from parts.  If you would be interested in buying a monoXover DIY kit, let me know.  Another option is to use a mixing board.  Some small mixing boards in the $50 to $100 range can provide this crossover functionality, i haven't tried this myself but it looks possible.

Step 11: Remove the speaker back

Picture of Remove the speaker back
First remove the speaker back plate.  this may be easy or difficult depending on the speaker.  If its impossible, you can remove the woofer instead to get access to the inside.

Inside the speaker (usually attached to the plate) is the built-in crossover.  Remove this and note the labels on the wires: you want to identify the "+" and "-" wires for both the woofer and tweeter.  usually it is also labeled on the woofer and tweeter itself if you need to double-check.

cut the wires to the crossover and remove it.

also, check around for where you have enough room to mount your amp and crossover.  on the Peavey PR12N, the plate is big enough to fit the amp.  The Pyle PPHP121 has a really big plate, easy to work with.  On the Behringer B212XL, there is no back plate at all, so i'll glue the amp inside the box somewhere.

Another option if you have no back plate - you can route all 4 wires from the woofer and tweeter outside the speaker, and attach the amp on the outside.

Step 12: Prep the back plates

Picture of prep the back plates
we need to attach both our crossover and our amp to the backplate (or elsewhere inside).

the photos show the mounting on a Pyle PPHP121 plate.

- remove the built-in crossover

- remove some of the input jacks that came with the speaker if needed

- put a power jack into the back (i used one of the existing holes, or just drill a new one)

- drill mounting holes for a pre-amp crossover.  (i'm using my  monoXover crossover).  i also put 2 holes so i can adjust the tweeter and woofer balance knobs from the outside.

- drill mounting holes to match my TK2050 amp

Step 13: Attach the pre-amp crossover

Picture of attach the pre-amp crossover

Step 14: Attach the amp

Picture of attach the amp
this shows a TK2050 "improved" model amp from sure electronics. 

notice i removed the fan from the amp.  when used inside the speaker, the woofer will create plenty of air flow to cool the amp, and the fan is not needed.

Step 15: Wire it up

Picture of wire it up
- if you are using my monoXover crossover, the woofer output will be "out2" on the amp and tweeter will be "out1" on the amp. 

- if you aren't sure which output has the high frequencies and which has the lows, test each output with a regular unmodified speaker to hear it.

- attach the woofer and tweeter to the amp.  NOTE:  depending on the type of crossover you use, you may need to FLIP the tweeter cables.  if you are using my monoXover crossover (or any 2nd order crossover), you need to flip the tweeter:  connect the tweeter's "+" to the amp's output "-".  the woofer is always connected "straight up" to the amp.  if you used an off-the-shelf mixing board, connect both of them "straight up".

- attach the power wires from the power jack to the amp

- attach an audio cable from the crossover to the amp input

- attach an audio cable from the crossover input to the outside of the speaker (use a jack if you want, my photo doesn't have a jack yet, but i'll put one in later)

Step 16: Put the plate back on

Picture of put the plate back on
it's done!

Step 17: Additional build photos

i built some more setups with other speakers, here are some photos of those.  check the photo notes for more info.

Step 18: The sound-off

Picture of the sound-off
We tested all the speakers.  Our reference is Deep's set of 120V active powered Yamaha's.  Deep has been using his mobile dance party setup all over san francisco for the past couple years so it is a good comparison.

Our active 24V speakers measured up!  I made 3 different systems all with 100W TK2050 amps.  The Yamaha reference speakers have a much higher power rating, but they are also less efficient.

At full volume, all the speakers were fairly close to each other, the B212XL was a bit quieter.  The Yamaha and the B212XL have notably better sound quality than the others.

In terms of power use, it was no contest.  with equal volume levels, all the 3 setups with TK2050 amps used about 1/3 the power of the Yamaha setup (with an inverter).

With 1/3 the power draw, it means we don't need a car battery to power these systems.  They run great on a much smaller and lighter gel cell.  plus no inverter is needed.

Step 19: More ideas

I haven't tried building my own speaker boxes yet.  it's rather time consuming.  i'm not sure if you can improve efficiency by making your own box, but you can reduce weight.  searching around instructables and the web you can find many projects about building your own boxes.

along with building your own box, you can also buy whichever woofer and tweeter you like best - including some very efficient ones.  you could also swap the woofer in one of the cheaper plastic PA cabinets for a better one.

Step 20: Credits

thanks to:


1-40 of 108Next »
George Rufato made it!3 months ago

This article was one of the most instructive in which I based myself to make my sound system =)


Nice. What are the specs? How does it sound? What kind of battery life are you getting? I keep going back and forth on what to use. Settled on decent parts for the price now I'm debating vented or not for outdoor use.

Anyways, nice looking build. I got the same speaker grill and this shows it actually will look really nice.

Tks! Specs here: http://www.instructables.com/id/Styrofoam-sound-b...

Sounds pretty nice, below a couple of vids... in the 2nd a guy's speaking at microphone



The battery lasts the entire event, which is about 4 hours... but not at the top max volume (even because at the max it gets unpleasant for people staying close to it)

About venting or not (I'm not an expert!) but as I briefly researched, it depends more of the speaker you'll use. Sealed boxes for subwoofers and vented for woofers.

Matthi4 months ago

Hi there,
I'm pretty inexperienced with audio technology. This instructables is awesome and so inspiring. I'd like to put a powerful PA together to be used with a crowd of 100-300 people on a large square. I think I can do it despite my lack of knowledge with this instructions. I just have a few technical questions to get me started.

For a speaker with 400W (http://www.bax-shop.nl/passieve-fullrange/devine-artis-15-400-watt-passieve-luidspreker/product-details.html#tabbox):

- do I need an amp that is capable of 400W also?
- we care for RMS only, and not for peak power, right?
- does it make sense to have so much watts? (I'd like to have a good sound including a full bass) or does it run the battery dry too quickly?
- do I need a couple or more batteries then?

Thanks for your help.

joelurbs Matthi1 month ago

I'm not super experienced but I know some of the basics. That speaker can handle that much but you can get good sound out of it running lower power. A 15" might be overkill for what you could really pump out of it on batteries. I'd do something smaller unless you have the power supply to support your goals.

I'm in the middle of upgrading a build but before I used two 12v12ah sla batteries in series and a plain on 2x100w sure digital amp. I was more than enough to drive a cheap 12" pa speaker rated for 300w rms and it was well received during a bike rave. I was maybe driving 30-40w to it and it got plenty loud.

I guess it depends on how portable you want it. The speaker you are looking at has a spl rating of 98db. At 30 feet away and 40w amp input it will be about 95db loud.

The more power you put into it the more battery power you will use. My setup theoretically was 40w/25.2v=1.58a that's maxing it out which will never happen but it means you could run the 12ah batteries for over 7 hours. My old set up went for almost 8 and I had it full volume most of the time and I never noticed a drop in performance. Bass will suck the power more and I found that in an outdoor setting with out a good supply of power you can't really get than thunder out of a mobile system. It can be good but nothing like a real system.

I'll post up my new project when I'm done.


I've got hold of a couple of Peavey Eurosys 3 speakers . they have
two large jack sockets on the back like the type that take guitar lead
type jack , anyone know how would I wire these to an amp?

Anyone know of a suitable mixer available in the UK - we can't get the Rolls here?

Matthi4 months ago

Where can I switch the mixer or amp to MONO?

Thomas P.A4 months ago

Hey all! I must be missing a step... all the recommended amps have speaker-wire outputs, but all the recommended speakers have 1/4 jack inputs! How do i patch those two without losing quality/efficiency?


Matthi Thomas P.A4 months ago

Good question, Thomas. Wouldn't a "raw wire to 1/4 speaker cable" work?

Thomas P.A Matthi4 months ago

Cool, didn't know that those existed. In that case, maybe I could just strip an old guitar cable at one end? I have some laying around that I wouldn't mind butchering, and that way I wouldn't have to spend $15 X 2....

DolphinAudio5 months ago

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DolphinAudio5 months ago

Please take the time to

look at our new and exciting line of Active DJ Speakers below and on our

website. If you have any questions please do not hesitate to contact us.


Exclusive Distributor:

Angelica Imports

(310) 919-6837




Thank You

saltvand5 years ago
The TK2050 thaqt I have looks i little bit different. See it here: http://img411.imageshack.us/img411/4465/img4302r.jpg IS there a way I can increase the volume on my model?

Did you ever find out a way to increase the sensitivity?

dan (author)  saltvand4 years ago
oh, the other solution is to use a powered mixer to boost the mp3 player signal before the amp. i'm using a Rolls MX51s which is about $50.
dan (author)  saltvand5 years ago
you have the 4-channel version. i think yours must have the pre-amp chips on the underside of that daughter-board. can you un-plug the daughter card and post a photo of the bottom side of it? (close up, use macro-mode on your camera).
ejones267 months ago

I know nothing about this but I got a chuckle out of the estimated weight of a car battery when he estimated it to be 40-50 lbs. Wow!!! That's one mother of a car battery. A huge 24V truck battery....maybe, but a car....naw. The battery in my car weighs maybe 10 lbs. I have removed it several times and if it weighed 40-50 lbs. I would be on compensation now moaning about my sore back.

Bowtie417 months ago

You can also get these very cheap at aliexpress

barrem017 months ago

Forgive me if my questions are naive.
Why discard the crossover that is already in the speaker?
The links to your monoXover don't seem to work, can I still get it in either kit or per-assembled form?
Would this do as a replacement for your crossover?


Is "bi-ampable crossover" the same as "pre-amp crossover"?

JeremyA27 months ago

This is a great instructable!

I wanted to add some info on the batteries: I recently installed new batteries on my RV and I did a lot of research and discovered lithium iron phosphate is a new chemistry that packs more amp hours into a smaller and lighter package that doesn't have the propensity to "blow up" when improperly charged like standard lithium-ion.

Take this battery for instance:


If you look around, there are several other brands out there that might be cheaper, I just picked the first one I saw on Amazon that was around 4-5 Ah.

It's 4.5 amp hours and weighs 1.45 lbs! Less than half the weight of an equally sized SLA battery. Lithium-iron-phsphate can also be discharged much more fully than lead-acid. A lead acid battery suffers permanent loss of life if it's discharged more than 50%. Lithium-iron-phosphate can be discharged down to 20% with no long term affects thousands of times. A gel lead acid battery can only be discharged down to 50% 200-300 times before the battery's life is pretty much gone.

So the 4.5 Ah Lithium-iron phosphate offers 3.5 "usable" Ah while the equivalent SLA rated at 4.5 Ah will only offer 2.25 usable Ah.

If you factor the weight the lithium battery offers about 2.5 usable Ah per pound while an SLA offers about 0.75 usable Ah per pound. If weight is an important factor, the lithium battery offers over 3x the usable power to weight ratio. meaning switching to Lithium-iron=phosphate would make your battery pack 2/3 lighter.

The price of the Lithium based battery is higher up front, but if you factor in that it can be re-charged over a thousand times compared to the 200-300 times of an SLA the long term cost if you actually use the battery very often is actually cheaper.

Just food for thought.


ukushu7 months ago

If a regular 24V power adapter is used to power the amp, would you happen to know how to power the 12V mixer from the same power source? Could I use DC/DC converter to convert to 12V from a single-rail 24V power supply while at the same time using it to power a 24V amp? Thanks.

vermeuliscious made it!1 year ago

I'm almost finished with my solar powered adaptation of this project. I used 48 reclaimed lithium ion batteries, a battery protection board from allbatteries, the rolls mixer, a a 30w panel and solar charge controller I got on ebay, a DC boost converter to supply a steady 39v to my 2 channel amplifier, and a pair of PR12 speakers. One thing i'm noticeing though is that despite some very impressive music volume, there really isn't much low end punch. This is of course the tradeoff with light, efficient stuff, but I'm searching for a relatively easy solution. One thing I'm considering is salvaging a computer or home theatre subwoofer and adding a second amp to drive it. I may not have time before burning man 2014 but we'll see.

what amp are you using?
if you need more power pioneers gmd 8056 is a good effecient amp with low power consumption.
instead of using the speaker from a sub, look at the free design of cubo 12 or 15 or tham12 or 15.
a normal hifi or car subwoofer only has an spl at 88-90.
I wound up building the separate sub-woofer from a very efficient and punchy 8" computer sub. Unfortunately I got all the way through hooking that up and STILL had no low end. It turned out the Rolls MX-51 completely attenuates the bottom end of the signal. I was very unhappy when I discovered that and as such I would very much NOT recommend the mx-51. Instead I swapped it out for a pioneer under-dash signal processor ($29 and works much better than the rolls). The sure-hifi power amplifier didn't last long at high volume in the desert heat (this was Burning Man project) unfortunately, and I'm looking into upgrading to a more powerful hifimediy unit.

Had you tried to take a look at the Pioneer gmd-8056 class-D amp, it's very popular in the mobile soundsystem community in Denmark.
It's very effecient.

Can be bridge to 300 watt.
It uses about 4A, in a 2.2 setup, with two tops and two subs.:)

royb111 months ago

The D in Class-D amps does not stand for "digital", it was just the next letter after C.

A tupperware box is a bad choice for anything that generates heat, it absorbs heat, deforms, melts.

The Peavey PR15N is rated at 400w RMS, why are you using such small amps?? If you don't give them enough power they're just going to drain batteries while sounding bad.

I really don't think the author knew what he was doing, which also doesn't seem safe.

Sureelectronics seems to have discontinued making it's TK2050 amplifiers. I'm assuming that the technology could only have gotten better, but i'm not sure where to start looking. Does anyone know what the 2014 equivalent of the sureelectronics improved TK2050 amp would be?

Is this what you're looking for?


I actually found a 2050 based amp that does 80W x 2channels at 39v into an 8ohm woofer. That newer sure amp looks like it would do the trick though.

Hey dan can you make a instructtable for me that I'm trying to make or tell me the best way to make it? I hunt and need a easy effective way to have a couple speakers maybe 6x9 and hook them up to an amp and power supply to hook up with my iphone. I have a app that has hunting calls and need a way to have good loud sound to make the noise be heard good... On hand all I have is a mtx car amp and car battery and 6x9 speakers. I am in desperate need of a goo way to make a portable system for hunting purposes... Please help me!!!
chriscab3 years ago
Thanks for the great instructions, Dan! Last night I debuted my setup with a TA2020, 12v/8Ah SLA & Gemini RS-308, created from your wonderful instructables, at the SF Bike Party and it was definitely a success. Got some great comments from people who were impressed with the sound coming from such a compact package. No trailer or car batteries for me, everything was mounted on my rear rack. I'll post pics later. Now with this portable powerhouse, tailgating and bbq picnics will be even more of a party!

So of course, I've now gotten the bug on wanting to get louder and cleaner. I'd like to upgrade to the TK2050 with the monoXover and another SLA. My question is: To get full power from the amp with 24V, I'd still need a pre-amp to boost the signal going to the amp, correct? And if so, should it go between the source/MP3 player & x-over, or x-over & amp?
Chriscab, did you ever get any advice on this question? I am doing a similar set-up and am also wondering where the pre-amp/mixer should go.
dan (author)  kristoballa071 year ago
put the pre-amp right after the mp3 player. see STEP 5, the 'mini mixer' i used has a built in pre-amp that works great for this.
smellex1231 year ago
is it worth running this from a 12v supply? i want to create a system to run off solar for my truck which has a 12v battery bank. My idea was to build(or get someone i know can) too create a 2 or 3 way crossover that sits before the amps and send the low to an active sub with the TK 2050 and use ta2021 fo the mid and a ta2020 for the high channel.Can you see any flaws in my logic? from what i read somewhere i got in my head that the tk2050 will only run at about 20% at 12v which is not what i want as the music i listen too is all about bass!!! is that right?
smellex1231 year ago
Hey dan wicked work here!! i've just bought two amps the ta2021 and ta 2020 from the indeed hi fi matey. Im thinking is it possible to wire it so the stereo input goes through the crossover first and then run the low freq into a sub box, of maybe say the ta201 amp wires up to 2 small woofers or 1 slightly larger woofer and use the mini ta2020 to run the high freq with a couple of 6x9s?
codesmith1 year ago
re: is their a way to have the portable sound system run off of a power supply and charge the battery at the same time?

Sure, if I understand your question. You need a solar panel, decent charge controller, and some sun. The panel, battery, and load (the sound system's amp) all connect to the charge controller. It can charge the battery and supply power to the load at the same time.
Sorry to necropost, but is their a way to have the portable sound system run off of a power supply and charge the battery at the same time?
Hey, did you ever get an answer to your question? I'm wondering the same thing...
This system worked perfectly with an ipod as a source but when I tried playing music from my laptop, I got a very disturbing hissing noise. I suspect a grounding problem but I have no clue about how the ground my 24V Sla battery to my aluminium mac... any idea?
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