I am planning a long camper bus journey through Europe.
I plan on performing in medium/large public spaces like squares, parks, and market places. My performance requires a few microphones, many guitar effect pedals, and a stereo speaker system with a reasonable low-end (min 60 Hz, pref. ~45Hz).
I imagine I will be strapping the setup to a standard two wheel trolley, and powering it with one (or two) 12V, ~50 AH, deep cycle gel battery. This battery can then be recharged with the solar panels on my camper bus. I am proficient with audio technology, but less so with tinkering and custom electronics. I am of course interested in maximizing energy efficiency, weight, and cost, but it is wroth noting that I will only be wheeling the setup from/to my vehicle, I will probably not be playing sets longer than 4 hours, and that I am willing to sacrifice a bit of effort for a beefier system.
I’m tempted to take the simple route of two large active speakers (eg JBL eon15 G2), and an 4+ channel behringer mixer fed with A/C from a wave inverter. However, I have been made aware that there are speakers with much better power efficiency, and that avoiding the use of an inverter would also save tons of energy.
I am grateful to hear critique of this "simple route" as well as suggestions tailored to my particular situation. I am ready to spend more for a smart, sustainable solution.
Thanks!
Lucas
I plan on performing in medium/large public spaces like squares, parks, and market places. My performance requires a few microphones, many guitar effect pedals, and a stereo speaker system with a reasonable low-end (min 60 Hz, pref. ~45Hz).
I imagine I will be strapping the setup to a standard two wheel trolley, and powering it with one (or two) 12V, ~50 AH, deep cycle gel battery. This battery can then be recharged with the solar panels on my camper bus. I am proficient with audio technology, but less so with tinkering and custom electronics. I am of course interested in maximizing energy efficiency, weight, and cost, but it is wroth noting that I will only be wheeling the setup from/to my vehicle, I will probably not be playing sets longer than 4 hours, and that I am willing to sacrifice a bit of effort for a beefier system.
I’m tempted to take the simple route of two large active speakers (eg JBL eon15 G2), and an 4+ channel behringer mixer fed with A/C from a wave inverter. However, I have been made aware that there are speakers with much better power efficiency, and that avoiding the use of an inverter would also save tons of energy.
I am grateful to hear critique of this "simple route" as well as suggestions tailored to my particular situation. I am ready to spend more for a smart, sustainable solution.
Thanks!
Lucas
Well using the two batteries in series (24V), and a bridged amplifier, you could get 64 watts into 4 ohms - and no inverter losses.
Interesting.. so that would require a bridgeable amp with lots of power and two passive speakers. I wonder how long, very roughly, the batteries would last in series (let’s say 24V and 30AH) powering speakers with a similar power to the JBLs @ ~70%. Much longer than eg the JBLs on a 12V 50AH + inverter?
I keep feeling like I should build something custom, like two Boominators or similar, which have been designed to be efficient off grid, and at the same time I just want to make this thing happen asap. Hmm.. it is true though that if I don’t have enough dBs and clarity in the frequencies my set won’t work as well, as it is so dependent on the amplitude and sonic quality. Also I may need to use an inverter here and there anyway when I want to incorporate some new element into the mix, or a laptop... it would be helpful to understand just how detrimental the use of an inverter is to the battery life.
Thanks again.
I keep feeling like I should build something custom, like two Boominators or similar, which have been designed to be efficient off grid, and at the same time I just want to make this thing happen asap. Hmm.. it is true though that if I don’t have enough dBs and clarity in the frequencies my set won’t work as well, as it is so dependent on the amplitude and sonic quality. Also I may need to use an inverter here and there anyway when I want to incorporate some new element into the mix, or a laptop... it would be helpful to understand just how detrimental the use of an inverter is to the battery life.
Thanks again.
Agree with Nigel and add:
1) reduce your requirements.
Even a flat down to 60 Hz system is big and expensive (and probably won't fit inside your van); 45Hz is for big Concert systems with rows of dedcated subwoofers below the stage.
No matter what they claim (JBL EON included), most portable systems have a real world, open air low limit around 100 Hz.
Anyway, if you play your Bass through them it will still be recognizable as a bass, so don't worry or overthink it.
2) As of solar panels, they are politically correct but still weak, large, expensive, and don't work on dark days or at night.
The sensible answer is to add charging plugs to your van, probably install a larger alternator, and recharge them while driving from place to place.
If necessary, leave the engine running on idle (ok , ok , tree huggers, don't shoot me) , just to recharge them.
And a 24V system as suggested above is a great idea.
And do some math to check what you can realistically pull from that system:
Your 2 x 12V x 50 AH batteries have a *nominal* capacity of 2x12x50=1200 WH (watts hours).
So you heve brute/raw 1200/4=300WH so your brute power consumption can not exceed 300W for it to last 4 hours.
So you can pull 150W RMS *audio* power into your speakers, plus feeding a mixer and effects and having a little spare "flight time".
You certainly don't want your "4 hour" system suddenly dying in the middle of a hot performance, disappointing your public.
So Nigel's suggestion of 2 65W RMS amps is perfect.
Edit: just read tenfold'spost.
1) forget "JBL power", I think they are around 350W each, as shown above you don't have stored power for more than 150W or so.
Inverters or not, there's only so much power stored in your batteries.
Furthermore I calculated based on your original 50 AH batteries; if you reduce even further to 30 AH ... you wont have much more than 2 hours autonomy.
2) be realistic with low frequency capabilities, they eat a lot of power for nott too loud perceived levels.
Speakers and human ears are both inefficient in that area.
Couple that to open air conditions and relatyively small portable speakers and the problem multiplies.
IF it's so important for Artistic reasons, fine, but then consider a portable gasoline generator.
1) reduce your requirements.
Even a flat down to 60 Hz system is big and expensive (and probably won't fit inside your van); 45Hz is for big Concert systems with rows of dedcated subwoofers below the stage.
No matter what they claim (JBL EON included), most portable systems have a real world, open air low limit around 100 Hz.
Anyway, if you play your Bass through them it will still be recognizable as a bass, so don't worry or overthink it.
2) As of solar panels, they are politically correct but still weak, large, expensive, and don't work on dark days or at night.
The sensible answer is to add charging plugs to your van, probably install a larger alternator, and recharge them while driving from place to place.
If necessary, leave the engine running on idle (ok , ok , tree huggers, don't shoot me) , just to recharge them.
And a 24V system as suggested above is a great idea.
And do some math to check what you can realistically pull from that system:
Your 2 x 12V x 50 AH batteries have a *nominal* capacity of 2x12x50=1200 WH (watts hours).
So you heve brute/raw 1200/4=300WH so your brute power consumption can not exceed 300W for it to last 4 hours.
So you can pull 150W RMS *audio* power into your speakers, plus feeding a mixer and effects and having a little spare "flight time".
You certainly don't want your "4 hour" system suddenly dying in the middle of a hot performance, disappointing your public.
So Nigel's suggestion of 2 65W RMS amps is perfect.
Edit: just read tenfold'spost.
1) forget "JBL power", I think they are around 350W each, as shown above you don't have stored power for more than 150W or so.
Inverters or not, there's only so much power stored in your batteries.
Furthermore I calculated based on your original 50 AH batteries; if you reduce even further to 30 AH ... you wont have much more than 2 hours autonomy.
2) be realistic with low frequency capabilities, they eat a lot of power for nott too loud perceived levels.
Speakers and human ears are both inefficient in that area.
Couple that to open air conditions and relatyively small portable speakers and the problem multiplies.
IF it's so important for Artistic reasons, fine, but then consider a portable gasoline generator.
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I would imagine an inverter is likely to be between 65% and 85% efficient?, depending on make and the actual power levels required.
But the bridged 24V solution I mentioned is probably all you need?, 64+64W should be plenty just for busking, you don't really want gig type levels.
You might even find that a single ended amp is loud enough (16+16W), which would help save battery life - and you could even configure your amps as either two bridged amps (for full power), or just use one as two single ended amps for low power.
If you've got an old car stereo you don't use, probably that's 16W in to 4 ohms (bridged) off 12V - you could connect in to it's amplifier and try how loud that works for you? Do it at home, using a car battery, and power your mixer etc. from the mains - as it's only a test of the power amp.
Or an even simpler test - connect your car stereo to your PA speakers, stick in a CD and see how loud it is 😀
Just a bit of extra info - I've just replaced the aerial on a small Carlsboro 'Speakezee' portable, it uses a 12V 2.2aH battery and a 6 ohm speaker - for an amplifier it uses a TDA1516BQ in bridged mode (basically a car radio IC).
The supposed power output is 20W, but that's certainly not proper RMS watts 😀
The supposed power output is 20W, but that's certainly not proper RMS watts 😀
Just remembered something else 😀
Back in March 1996 the UK magazine EPE did a portable PA (actually a reprint of an Australian magazine article), it gave higher power from 12V by using a TDA1562Q IC, which boosts the voltage higher only when needed, allowing up to 70W (according to the datasheet).
EPE Magazine March 2006
Back in March 1996 the UK magazine EPE did a portable PA (actually a reprint of an Australian magazine article), it gave higher power from 12V by using a TDA1562Q IC, which boosts the voltage higher only when needed, allowing up to 70W (according to the datasheet).
EPE Magazine March 2006
There are 2 ways to go about this to get the maximum from the batteries..
a) Buy a new car audio power amplifier because it will be digital and have the highest possible efficiency.. and then build or buy some efficient PA speakers.This also eliminates the need for a large inverter.
b) Buy the latest designed powered PA speakers you can find(EV ZLX) because again they contain a very efficient amplifier and power supply.
a) Buy a new car audio power amplifier because it will be digital and have the highest possible efficiency.. and then build or buy some efficient PA speakers.This also eliminates the need for a large inverter.
b) Buy the latest designed powered PA speakers you can find(EV ZLX) because again they contain a very efficient amplifier and power supply.
Been doing a bit more searching - to find that SiliconChip Australia have done a new version of the PortaPal, Dec 2013 to Feb 2014 - and according to the preview below it now gives 100W.
December 2013 - Silicon Chip Online
December 2013 - Silicon Chip Online
Thank you for all the valuable feedback!
I'll post more in a bit, but one priority question has to do with the batteries. I just suggested 50AH as it seemed like a good mid-range option when I browsed the selection online. Now that it turns out they will give me much less power than I had first expected, are there any specific reasons I shouldn't focus on changing this weak link in the chain instead? I can find Leisure batteries with AHs up to 200 and more.. is there a catch I'm not aware of?
I'll post more in a bit, but one priority question has to do with the batteries. I just suggested 50AH as it seemed like a good mid-range option when I browsed the selection online. Now that it turns out they will give me much less power than I had first expected, are there any specific reasons I shouldn't focus on changing this weak link in the chain instead? I can find Leisure batteries with AHs up to 200 and more.. is there a catch I'm not aware of?
Again, thanks everyone for your input! Really helping me work through this and I feel like I’m starting to realize the reality of the situation I’m putting myself in!
I guess that while browsing integrated amps that boast 8+ hours I was expecting the shift to bulky deep cycle batteries would provide tons more power. I now understand that I need to give up the thought of a juicy low-end.. I’ll make it work without. Still, I’m a bit skeptic to calling it safe with the wattage for the large open spaces I plan on occupying. In my experience a portable speaker that sounded huge in your apartment completely drifts off in even the slightest breeze when out in the open.
Here’s where I’m currently at with the options conanski laid down..
A) PASSIVE: I’m having trouble putting together the passive / car amplifier option as I feel like I might be looking at the wrong online stores, eg the 60W speakers I’m finding on thomann, well I can’t imagine them offering even the minimum of my needs. And I don’t know about car amplifiers other than that a friend once recommended the LP-2020A+ Lepai Tripath Class, it’s a good deal for the price but as far as I can tell can’t handle my requirements. They have another beefier model Lepai LP7498E 200W Class D Digital Amplifier but I can’t really tell if it fits the bill.
As for the mixer, if need be I could probably get by with a 9V Behringer 4ch, and guitar pedals and DI boxes are already 9/21V compatible, in other words, no inverter losses! 🙂
B) ACTIVE: 2x EV ZLX 12P, 250W rms + mixer and other stuff ~50W = 550W. Add a semi-optimistic 80% efficiency from the inverter and the “real” battery load is ~690W to produce 550. For four hours of showtime that would require 2 batteries with a minimum of 115AH each. Hmm. (quick question, since the speakers have 1000W peak, does that mean that my inverter would need to be able to supply a min of 1250W just to turn them both on, even though their combined usage after that is only 500W?)
Switching to something like the 180W Behringer K1800FX Ultratone Behringer K1800FX Ultratone - Thomann Suomi would lower the battery requirements to 85AH.
Oh and JMFahey, I will definitely look into charging plugs from the alternator! 🙂 The nature of my playing will be more sporadic than a daily busker, so I still trust in solar, or friendly locals here and there, but certainly no point in wasting the excess from the fossil fuels I’ll be burning on the road anyway!
I guess that while browsing integrated amps that boast 8+ hours I was expecting the shift to bulky deep cycle batteries would provide tons more power. I now understand that I need to give up the thought of a juicy low-end.. I’ll make it work without. Still, I’m a bit skeptic to calling it safe with the wattage for the large open spaces I plan on occupying. In my experience a portable speaker that sounded huge in your apartment completely drifts off in even the slightest breeze when out in the open.
Here’s where I’m currently at with the options conanski laid down..
A) PASSIVE: I’m having trouble putting together the passive / car amplifier option as I feel like I might be looking at the wrong online stores, eg the 60W speakers I’m finding on thomann, well I can’t imagine them offering even the minimum of my needs. And I don’t know about car amplifiers other than that a friend once recommended the LP-2020A+ Lepai Tripath Class, it’s a good deal for the price but as far as I can tell can’t handle my requirements. They have another beefier model Lepai LP7498E 200W Class D Digital Amplifier but I can’t really tell if it fits the bill.
As for the mixer, if need be I could probably get by with a 9V Behringer 4ch, and guitar pedals and DI boxes are already 9/21V compatible, in other words, no inverter losses! 🙂
B) ACTIVE: 2x EV ZLX 12P, 250W rms + mixer and other stuff ~50W = 550W. Add a semi-optimistic 80% efficiency from the inverter and the “real” battery load is ~690W to produce 550. For four hours of showtime that would require 2 batteries with a minimum of 115AH each. Hmm. (quick question, since the speakers have 1000W peak, does that mean that my inverter would need to be able to supply a min of 1250W just to turn them both on, even though their combined usage after that is only 500W?)
Switching to something like the 180W Behringer K1800FX Ultratone Behringer K1800FX Ultratone - Thomann Suomi would lower the battery requirements to 85AH.
Oh and JMFahey, I will definitely look into charging plugs from the alternator! 🙂 The nature of my playing will be more sporadic than a daily busker, so I still trust in solar, or friendly locals here and there, but certainly no point in wasting the excess from the fossil fuels I’ll be burning on the road anyway!
🙂
Well, now you know the Math, it´s quite simple.
Just correct it a little: consider power amps eating 50% more than what they put out as sound, so your 250W ones will count as 350W loads each.
Don´t worry about peak and other marketing watt types, 50% above RMS is a safe estimation.
And friendly locals who let you plug your battery charger are great.
Mind you, I love the solar panel idea, but to be realistic, what we can afford still means low power.
They are great in an island, remote jungle or alpine hut, small saiboat, etc, to charge cellphones, run a tablet or netbook, maybe charge a battery for an emergency low power transmitter ... not much more.
Well, now you know the Math, it´s quite simple.
Just correct it a little: consider power amps eating 50% more than what they put out as sound, so your 250W ones will count as 350W loads each.
Don´t worry about peak and other marketing watt types, 50% above RMS is a safe estimation.
And friendly locals who let you plug your battery charger are great.
Mind you, I love the solar panel idea, but to be realistic, what we can afford still means low power.
They are great in an island, remote jungle or alpine hut, small saiboat, etc, to charge cellphones, run a tablet or netbook, maybe charge a battery for an emergency low power transmitter ... not much more.
Calculation on power requirements of batteries are too pessimistic imho because average power consumption is significantly below rms power capabilities of amps with real life music even with amps driven into clipping.
FYI, Yamaha just came out with their 12V mixers. To date the most quality mixer available in 12V:
Yamaha MG06X | Sweetwater.com
Yamaha MG06X | Sweetwater.com
+1
Live music tends to have a lot of dynamic range, so, while the peaks may be pulling 690w, they'll be very brief, if you do run up to full power. Hint: feedback will be an issue long before then.
Chris
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