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batteries, amps, speakers vs effect and play time
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odp View Drop Down
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Points: 53 		Post Options Post Options   Thanks (0) Thanks(0)   Quote odp Quote  Post ReplyReply Direct Link To This Post Posted: 12 July 2012 at 12:22pm
Originally posted by slaz slaz wrote:

Originally posted by odp odp wrote:

Hi all,
How in the world can they get 24 hours of play time?


Enabling HPF on your amplifers at 60-70 can have a dramatic effect on run-time.

If you want to play low (e.g. down to 40Hz or so) AND you want to play long .... well get some BIG feckin batteries. (Also, if you need to manhandle them, consult your chiropractor. Oh yeah, and eat LOTS of Weetabix).




I do want to go loooow, the speaker construction I got going plays as low as 35Hz.
Low frequencies draw more power right, so there is no way to go around that?

That is something i also notice with a lot of these high efficiency 12v rigs, they have a HPF set to aroung 60-70Hz

So my choice of batteries is not completly off hehehe
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Johan
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Points: 53 		Post Options Post Options   Thanks (0) Thanks(0)   Quote odp Quote  Post ReplyReply Direct Link To This Post Posted: 12 July 2012 at 12:26pm
Originally posted by slaz slaz wrote:

Originally posted by Earplug Earplug wrote:


235Ah battery isn´t exactly small... LOL


True. Just a tad different to my "6800mAh" Li-ON packs (= really about 4000mAh) ... <500g - size of 20 cigs - fits in your pocket, and powers a 2020 amplifer the whole, day Tongue




See that is what I mean, I break my back everytime I want to play, carrying those bastad batteries around. If you had a battery like mine you would probably be able to play music for decades Dead
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Johan
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odp View Drop Down
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Points: 53 		Post Options Post Options   Thanks (0) Thanks(0)   Quote odp Quote  Post ReplyReply Direct Link To This Post Posted: 12 July 2012 at 1:12pm
Then lets say we have a
41Hz AMP15-PS-XP amplifier (2x300W @ 4ohm)

We'll need a step-up DC/DC converter from 12v to +/- 60V (max.) for instance
Coldamp CPS80

As the datasheet mentions in the big warning at the bottom it draws in the excess of 60A

So how would I go about converting that into some useful data?

Is it not true that Ampere-hour = A * hr ?

If so then the smps will draw 60A continues pr. hour  and that is 60Ah?

Edited by odp - 12 July 2012 at 1:26pm
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Johan
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slaz View Drop Down
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Points: 1880 		Post Options Post Options   Thanks (0) Thanks(0)   Quote slaz Quote  Post ReplyReply Direct Link To This Post Posted: 12 July 2012 at 2:07pm
Originally posted by odp odp wrote:

Then lets say we have a
41Hz AMP15-PS-XP amplifier (2x300W @ 4ohm)

We'll need a step-up DC/DC converter from 12v to +/- 60V (max.) for instance
Coldamp CPS80

As the datasheet mentions in the big warning at the bottom it draws in the excess of 60A

So how would I go about converting that into some useful data?

Is it not true that Ampere-hour = A * hr ?

If so then the smps will draw 60A continues pr. hour  and that is 60Ah?


Yes but it sounds like you need to do  a bit of reading about "music"  "crest factor" (try using those as search terms) ..... music signal compresion is also relevant.
REMEMBER....POLITICIANS AND DIAPERS SHOULD BE CHANGED OFTEN AND FOR THE SAME REASON
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I am reading and reading.
Feel free to drop me more resources Smile
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Johan
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I don´t know what it´s like up your way, but down here car booster amps seem to be fairly cheap - cheaper than that Coldamp CPS80!

http://www.ebay.es/sch/i.html?_from=R40&fts=2&_trksid=m570&_nkw=etapas+de+potencia+coche&_sacat=See-All-Categories

And P = Power! Smile
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Originally posted by Earplug Earplug wrote:

I don´t know what it´s like up your way, but down here car booster amps seem to be fairly cheap - cheaper than that Coldamp CPS80!

http://www.ebay.es/sch/i.html?_from=R40&fts=2&_trksid=m570&_nkw=etapas+de+potencia+coche&_sacat=See-All-Categories

And P = Power! Smile


Also here in Denmark. But they're (pretty much) all inefficient crap. Even if they were €1 including freight, they'd not be worth it for a 12V system.



Edited by Saturnus - 12 July 2012 at 6:07pm
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Originally posted by Saturnus Saturnus wrote:

Originally posted by Earplug Earplug wrote:

I don´t know what it´s like up your way, but down here car booster amps seem to be fairly cheap - cheaper than that Coldamp CPS80!

http://www.ebay.es/sch/i.html?_from=R40&fts=2&_trksid=m570&_nkw=etapas+de+potencia+coche&_sacat=See-All-Categories

And P = Power! Smile


Also here in Denmark. But they're (pretty much) all inefficient crap. Even if they were €1 including freight, they'd not be worth it for a 12V system.



Hey Saturnus, Let me get inside your head spill some knowledge on me.

I read up on the topic of quiescent current use, the amount of power the amp will use by itself with no load, I guess this is also what you call idle power.

Efficiency in an amplifier is the amps ability to convert an input power into output power with minimum loss in the form of ambient energy, without compromising sound quality.

A music signal is composed of many different pitches, peaks and drops (looking at a waveform) it is obvious that there is highs and lows but these are only current at very small time intervals. It is also clear that there is a mid section that is more coherent. I understand a musical signal is different from the RMS, since RMS is the power avarage of a signal.

But I need ellaboration on this topic  to understand what you mean?

I read this http://www.prosoundweb.com/article/how_many_watts_loudspeaker/

And the bloak says that "Example: A loudspeaker has a 250-watt RMS rating. Twice this is 500 watts. Therefore the acceptable range for the power amplifier to use is from 400 watts (0.8 x 500) to 625 watts (1.25 x 500). Anything larger is potentially excessive power. Anything smaller can cause damage from the amplifier clipping. Remember that the power amplifier output you select must be rated for the nominal impedance of the loudspeaker (i.e., 16, 8, 4 or 2 Ohms)."

If this is somewhat true, then what am I missing? Your boominator has an amp that deliveres 2x20W rms the bass speakers in use are rated as 100W rms. Though they also mention that they have a Sensitivity @ 1w, 1M: 96 dB

My brain needs a little break now, I've been studying for nearly 12 hours straight.

Again resources a very much welcome, I'm here to learn from the best Smile
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Johan
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Points: 53 		Post Options Post Options   Thanks (0) Thanks(0)   Quote odp Quote  Post ReplyReply Direct Link To This Post Posted: 12 July 2012 at 11:15pm
got it! Oh and by the way, I'm not really interested in looking at amps to buy I like to build them my self ie. 41hz and coldamp. Second I'm looking to get some theoretical wizardry Big smile
But thanks for the link
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Johan
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Points: 473 		Post Options Post Options   Thanks (0) Thanks(0)   Quote bitSmasher Quote  Post ReplyReply Direct Link To This Post Posted: 12 July 2012 at 11:38pm
Originally posted by odp odp wrote:

And the bloak says
it's "bloke", mate... Wink

Also, whilst I have basic grasp I'm in no place to discuss theory - but I will say that grabbing a multimeter and playing around with a system will give you great insight in to the topic.
Try different speaker configurations, see how amps perform close to their limits and also try different sources (or at least styles of music). It's good fun!


Edited by bitSmasher - 12 July 2012 at 11:44pm
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The amp6 is only 2x15Wrms as any other class D amp on a 12V supply playing into 4 ohms will be.

Power output depends on 3 factors: Supply voltage, speaker impedance and amplifier efficiency. Nothing else.

That also means that each driver only sees 7.5Wrms. Is it possible to damage the amplifier by this? No. It has built in protection, and frankly if a person can't hear severe clipping distortion and turn down volume way before that would become a problem he should probably not listen to music at all as he will have permanent hearing loss.

Technically though with music signals the average is far less. The Boominator for example uses about 4.2W at max volume with music. And 0.7W of those is quiescent current use which is not the same a idle consumption, it's the current used for operations that is unrelated to variations in output power. Idle consumption includes various bias currents as well. So in fact each woofer only sees 0.8W on average at full volume and each piezo sees about 0.05W (the resistor in series sees the other 0.05W).
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lol thanks!

That sounds like a good project for a Friday afternoon, especially in  relation to what Saturnus jus wroteLOL
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