HELP! line-level crossover design for solar-powered biamped soundsystem

[PinkNoiser]

Originally Posted by picowallspeaker

The Ic doesn't run on single supply , as it's specified to work with ( max ) + and - 18 V supply . It's a state variable filter.
Don't you know what a 9 volt battery is ?
It's also available as a rechargeable battery , with a little lower voltage , 8,2 V .

Yep, actually i don't know what a transistor battery is. Btw, i'm not going to use any batteries, as the project is intended to be solar powered. Now more than ever, because a battery won't solve the problem but would cause others, and two batteries would barely be a workaround that would lead to more problems again!

Lol, i made a terrible mistake assuming it's single supply. Btw i've still got two options:
-Get a state variable filter that works with single supply (they exists, rscomponent sell them, that's why i assumed it was single-supply too)
-Buy f**ktons of MAX1044, and use one of this to get the negative voltage (i would still need them if using just one battery).

PS: just saying, i did some comparison between various opamps, and I made a quick chart (based essentially on SR, Noise, cost):
Winners: OPA4134, TLE2074
Followers: OPA228
Decent: TL074 and NE5532/4
what do you think about my ranking?

[cyclecamper]

Have you ever attempted an audio system from solar? Even fully regulated, you will still need either batteries or many boxes of filter caps in order to get it to really sound good for those crescendos. Assuming you have something against batteries, start investing in large electrolytics.

[cyclecamper]

It's like trying to take a bath from a little trickle of water. Having a bucket to fill lets you rinse your hair a lot better.

Is this sponsored by some solar initiative? Because if you just want good sound for Burning Man in the desert during the day you should still throw in a few big batteries.

So you're using a large commercial solar regulator, but no inverter? How robust are the caps in it?

[cyclecamper]

Pretty good solar panel to put out 500 watts continuously in all weather. So is it rated at 2000? How many such speakers are you driving?

[PinkNoiser]

The main idea is to have a portable soundsystem that do not rely on external power supplies.
This is the way we like it. Because it's lighter, because it's funnier, because it's somewhat original.
If we want to use batteries that would run for more than half an hour, we should buy large acid-lead batteries, that would be heavier than the rest of the whole system, we should remember to keep them charged, under manteinance the whole year, and we should still re-buy them every season just to use them in some random occasions. Solar cells would be just an extra, and this is not our project.
If we wanted a battery-powered system, we'd go in some audiocar shops, give them our money, and go somewhere to celebrate.

Yes, maybe we will need to implement some "bucket": maybe it would consist in a rack of five SMALL 6V acid-lead battery. But it's a just-in-case, and don't affect the project in any way, at this stage.

We have already built smaller solar stereo with no issue. The tk2050 itself was tested with a small 30W (1.7A, 17V, the one that will drive the ta2024 amp for tweeters) one month ago, without any kind of regulation, and sounded quite loud no-problem for hours on one channel.

Not to be arrogant, but maybe some of you are understimating the sun . Even if some clouds occasionally covers the sun, the cells won't stop working (actually, they work fine upside-down too). The amplifiers board have great efficiency and large voltage working range, the system isn't intended to work at full power in every occasion (but, obviously, it will be designed as it should be). If the sky gets cloudy, we'll listen to music at lower volume, a couple of batteries won't help for long time in any case. If the sky gets MORE cloudy, we would come back home, and the stereo would be turned off. And we are not in the desert, we are in Italy: due to lower temperatures, solar cells works better here :P .

We are not sponsored, but, if this can explain something, i can tell you that we are physicists

Didn't understand your last question. (i'm so sorry, but my english is crap...)

[PinkNoiser]

Originally Posted by cyclecamper

Pretty good solar panel to put out 500 watts continuously in all weather. So is it rated at 2000? How many such speakers are you driving?

4x ciare CM200 woofers and 2x ciare ct267 tweeters.
We will get a solar panel to put out the needed watts (that we will measure after some testing) with sunny weather. no sun = no party = no stereo. we don't care ratings. even if all the solar cells we have satisfies/exceeds their rating values, yes, we will buy a "10000000W" if needed.

I'm glad that you're interested in our project, i'll be happy to give you all the infos about that, it will be terrific if you will share some knowledge with us.

How we'll feed our poweramps is an interesting subject that I would discuss for months if you like (despite of the foreign language).
But despite the choice around photovoltaic stations or batteries, nuclear or hydroelectric power plants, i think it's better if we don't go off-topic too much.

Could you please contribute to this thread's subject?

[PinkNoiser]

Originally Posted by cyclecamper

It's like trying to take a bath from a little trickle of water. Having a bucket to fill lets you rinse your hair a lot better.

Actually, that's completely wrong. I don't want to take a bath. I want to take a shower. You don't have to fill a tub and then empty later, you want a continuous stream. Buckets can flatten the peaks, but would be useless if the hole at the bottom is wider than the incoming flow.
Luckly, there's no trickles, but an heavy rain. Main problems with solar power is not the flow's intensity, but that there's no buckets large enough to capture preserve it. Solar energy density is most of the times much bigger than the cell's capability to absorb it, and it's like filling a tub with rain using a spoon: if the rain gets thinier, you won't even notice, and you'll be wasting 90% of it anyway.
Like the rain, it's hard to have a bath with solar power, but it's quite easy to get a full shower when it comes

[picowallspeaker]

Cyclecamper was saying to use some BIG capacitors ( caps ) to overcome the power surges . Indeed , those caps belong to automotive area . They may be one or two Farad with very low voltage ( 18-30 V).
Funny ,because you were talking about the forces of nature ( cinically , hydrocarbons may be good ...though they stink & burn ) and i've read once that if the earth was a plate of a capacitor , and the sky above the other one , the capacitance between those plates would be ....1 F !
BTW Did you think that your source / player would be eminently supplied by batteries ...

[gfiandy]

Hi,

I used a SP6661EN however I don't think this will be suitable for your application as it is intended for lower voltages (5v) it is also quite low power. I was only running a couple of opamps.

In terms of the choice of opamp. I would use NE5532, these are really low cost, very stable, low noise and sound very good for their price. If you want to spend a bit more then OPA2134 would be a good choice, this sounds a little better and I think it uses a bit less power (But I can't remember for sure), its also good for stability but needs more careful decoupling than the NE5532. Also it costs allot more and in this kind of system I don't think you will hear the difference.

I think your idea of a small battery to cover if you want to play loud when there is a cloud is probably a good idea. As you pointed out if you want to party into the night you will need fairly large SLA (Solid lead acid) batteries then recharge them the next day but it sounds like this is not your plan.

I hope your build comes together well. I have not used the MAX part you mentioned but I have had good results with most of the MAXIM parts I have used they usually seem to be fairly well designed.

If you want to make the project even lower power I have used MAX9709 which sound really good and have an efficiency around 80 - 90%. There is also a good thread on the class D forum on solar boom boxes. Its not quite the same concept as yours as they seem to want to play all day and night! but there is lots of good ideas there.

The Boominator - another stab at the ultimate party machine

Regards,
Andrew

[PinkNoiser]

Originally Posted by picowallspeaker

Cyclecamper was saying to use some BIG capacitors ( caps ) to overcome the power surges . Indeed , those caps belong to automotive area . They may be one or two Farad with very low voltage ( 18-30 V).
Funny ,because you were talking about the forces of nature ( cinically , hydrocarbons may be good ...though they stink & burn ) and i've read once that if the earth was a plate of a capacitor , and the sky above the other one , the capacitance between those plates would be ....1 F !
BTW Did you think that your source / player would be eminently supplied by batteries ...

I know something about the big car audio caps. They are quite huge (1- 5F). But they don't work if they doesn't also have a quick discharge! In fact they are intended to flatten the bias voltage when a peak of current is drained. They are fast peaks, fractions of seconds. It improves dynamic range but it would be scary huge to work as a voltage supply for minutes..in fact, the 'heart surface' is confrontable with the total surface of this big capacitors' inside
we will certainly use capacitors in the supply regulation section. Element's size will be know when we will test the total system and its power needings
and to do that, i need to route the inputs, so help me

ps: burning fossil fuel usually make a lots of noise (and bad rippled power)! this would mean that we should need a much louder soundsystem and this would ruin the SNR ratio
pps: with an simple lm317 is easy to obtain a +5V and solder it to an USB port