Can someone please explain Ohms?
SolidSqual
Posts: 5,218
I have two buttkicker mini LFEs which have a nominal 4 ohm impedence. My amplifier runs 100 watts at 4 ohms and 100 watts and 2 ohms. So I understand that I can run both the buttkickers on the amp, but would their performance be affected?
Post edited by SolidSqual on
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No, you should be ok, as long as the amp can handle 2 ohm loads.
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If your amp is rated 100 watts at both 4 and 2 ohms, it means it is not capable of putting out more current (as the wattage is not increasing with lowering of impedance). I will little concerned providing a consistant load of 2 ohms to this amp.-izafar
Goldenear Technology Triton 1 - Benchmark AHB2 - Benchmark LA4 - Auralic Vega - Auralic Aries Mini - Marantz TT-15S1 - Clearaudio Nano -
P = I^2R
100 watts into 4 ohms is 5 amps
100 watts into 2 ohms is ~7.1 amps
How do high current amps increase wattage as speaker load goes down?
I know I've seen statements that tube amps do go down in power with reduced speaker load?
Anybody have a quick primer on amp design? I know I may be looking at this in a simplified manner.Signature goes here -
Google it. There are at least 10 billion online tutorials on amplifier design and theory.Proud and loyal citizen of the Digital Domain and Solid State Country!
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seo wrote:
How do high current amps increase wattage as speaker load goes down?
An ideal amp will double the power as the impedance is halfed. For instance...
100 watts at 8 ohms,
200 watts at 4 ohms,
400 watts at 2 ohms.Speakers: LSi9 x 2, LSic, LSiFX x 2, Velodyne HGS-15
Amps & Power: Rockford Fosgate T8004 x 3, Cascade Audio APS-55 power supplies x 5, and 1 farad capacitor.
Electronics: Denon 3806, Toshiba HD-A1, & Sony KDL46XBR2
Accessories: Anti-IC interconnects, 8 Mondo Traps from Realtraps, and Salamander furniture. -
Seo, the basic answer is that another form of Ohm's Law is I=E/R(current equals voltage divided by resistance), so if resistance(or impedance)is reduced from say 8 ohms to 4 ohms current would theoretically be doubled if voltage could remain constant. From the form of Ohm's Law you cited(P=I(squared)R) it follows that if current is doubled and resistance halved, the net result is that power would theoretically be doubled. This full doubling is rarely the case in practice because the power supply doesn't maintain the necessary voltage and current and the power available into 4 ohms is increased by a smaller amount.
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John K. wrote:This full doubling is rarely the case in practice because the power supply doesn't maintain the necessary voltage and current and the power available into 4 ohms is increased by a smaller amount.
This is exactly why i use a car amp with my lsi9 speakers. It can double the power all the way down to 2 ohms (and all the way down to 1 ohm if I unbridge the amp).Speakers: LSi9 x 2, LSic, LSiFX x 2, Velodyne HGS-15
Amps & Power: Rockford Fosgate T8004 x 3, Cascade Audio APS-55 power supplies x 5, and 1 farad capacitor.
Electronics: Denon 3806, Toshiba HD-A1, & Sony KDL46XBR2
Accessories: Anti-IC interconnects, 8 Mondo Traps from Realtraps, and Salamander furniture. -
It does not matter if the amp does not exactly double. If it gets close say within 25-50 watts or so on a 200 watt @ 8 ohm amp you have a quality piece.
As suggested a google will offer many detailed explanations, but down and dirty, as the resistance is decreased more current (amperage) can flow down the line.
RT1
