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Speaker build works, but not at 55%+ volume


Nitrox
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Hey guys! Not sure if this a crossover issue or my stereo amplifier or both! I just finished my speaker build up yesterday night (3rd order crossovers for my tweeter and woofer). I get great audio from 1-54%  volume using my Lepai LP2020TI Stereo Amp, but when I crank the volume up past that 54% I get audio that cuts in and out. Is this because my amp is crap? Did I pick the wrong amp? do I have a loose wire? PLEASE HALP. I can't find any good articles on troubleshooting this. Thanks in advance for your time!


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ronL
 ronL
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Hi Nitrox,

my first thought: what power supply do you use for the amplifier? If the power supply run short of current, the amp has no other option but to clip. Basically, if it runs out of current, it has no other option than to lower the voltage. The symptoms that you describe point into some non linearities related to the signal level. If this is the cause, it might help to try a beefier power supply. The power supply of your amp is like the engine in your car, you won’t go fast with an underpowered engine. 😉

cheers, Ron


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Nitrox
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It's whatever came with the external amp - I think it's 12v - 3A. The amp is as cheap as it gets. Does a "beefier" crossover require more power than a simple one? I am EXTREMELY new to speaker building as this is my first set I've made. I'm gonna order a small Dayton Audio amp and a 24v power supply for that. Thank you for the help 😁


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ronL
 ronL
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A 12V 3A power supply can deliver 12x3 = 36W. If you ask your amplifier to deliver more, the power that is supplied to your speakers is limited by the 36W that the power supply can deliver. There is simply no more power available. The cheapo power supplies often don’t have the margin to deliver higher peak power than rated. Hence, with the 3A power supply, it is safe to assume that it isnot possible to put 2x20W into your speakers.

By the way, what do you mean with a “beefy” crossover?


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Nitrox
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@ronL

I see! That's pretty simple math. So, if I were looking to upgrade would I be looking at 15V-3A? or something different? Also, if I only plug in 1 speaker is it capable of inputting 36W into that circuit or is it always going to 18W? 

When I say I should have said "3rd Order" vs a "first order" crossover. My fault. 


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ronL
 ronL
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A power supply as we know it is a voltage source. Meaning that it will do it’s best to deliver the rated voltage. The 3A you mentioned is the maximum amount of current that it is capable to deliver. If you try to pull more currentfrom the supply, it just won’t. There is just not enough power. The power source will have no other alternative than to lower the voltage. Resulting in less headroom for the amplifier, resulting in clipping. The tops of the sinewaves are just chopped off. And yes, this sounds quite horrible. 

I would say, go for a power supply that is capable of delivering way sufficient current. Rather go for a 12V/6 A (ore more) one than a 15V/3A one.

 

about the crossover; the impedance is what counts in terms of loading your amplifier. First order or third order is not the main concern. If there are really low impedance dips in the impedance vs frequency characteristic is a problem for many amps though.

 

 


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123Toid
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@ronl Perfectly stated.  @nitrox listen to this man.  😀 

https://www.youtube.com/123toid


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Nitrox
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@ronL

I genuinely appreciate the lesson on the PS, voltage, and amperage. So, if an amp is rated for 12v (as an example), you can get away with drawing more power by getting another 12v supply with more amperage? 

And after speaking with @123Toid, I believe my issue is coming from my current crossover and not my amp. I will definitely be coming back to the PS after I fix my crossover issue. I just have to learn about being out of phase now. There's a lot that more that goes into speaker building than I originally thought 🤪 


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