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LG CK99 Speakers w/o amplifier (What should I do?)

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DkapCK99

New Member
I'm trying to get these speakers pushed to their potential. However the claims on the RMS power handling of these speakers is confusing me, along with the original amplifiers specs.

CK99 Speakers (2) : 1,250W RMS (2 Way 3 Speaker) (6" Woofer x 2) (1" Tweeter) (8Ohms) 2,500W Peak
CK99 Subwoofer (2) : 1,250W RMS (15" Subwoofer) (8Ohms) 2,500W Peak
So based off the manual specification. 4 Inputs to power the 2 units. 2,500W RMS per unit 5,000W Peak. Either 4 or 8 ohms depending on how they are wired together afterwards.

CK99 Amplifier
Total Output Power (RMS) : 5,000W
HIGH (2) : 1,250W RMS (8 Ohms at 1kHz, 30%THD) Sidenote : WTF 30% distortion!
LOW (2) : 1,250W RMS (8 Ohms at 70kHz, 30%THD)
Power consumption : 320W

I have a JVC RX 815VTN Receiver. I have both the CK99's (Sub's and Speakers) connected to ONLY the left channel (Right channel doesn't seem to be working). Then running everything in mono from my audio source (PC). It does seem to push them all well with just the 1 Channel. I'd imagine this is a 2 Ohm load as they are wired all in parallel so I'm surprised I haven't damaged it as of yet, though I haven't tried pushing the volume too high to avoid damage happening to the receiver.

So that just leaves me with a few questions, and I can't find too much online about people using these without their own amplifier.

Questions :
1. The power claims seem to be stretched extraordinarily, how much power could these speakers actually take?
2. How could the amplifier do 1,250W RMS on 4 channels, yet have a power consumption of 320W?
3. The JVC has a rated output power of 120W at 8Ohms, 0.007%THD with 2Ch driven. Would it be more power only driving the 1 channel? Sidenote : WTF 0.007% distortion!
4. If there is still lots of headroom left for me to put power into these speakers (If all the numbers LG claimed somehow aren't all fudged). Should I sit and wait until I hopefully find one of the original amps for sale and use that, or should I purchase a power amplifier that could line up with the needs of these speakers (ex. Behringer NX6000D which delivers 2 x 3000 Watts into 4 Ohms, 2 x 1600 Watts into 8 Ohms)?
 

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This is an answer from the past, so it may be based on outmoded assumptions. And I'm no whiz in terms of electronics even when I think i understand the question.
From the model numbers, it sounds like you either have self powered speakers and a self powered subwoofer, or a box that connects to the speakers. If so, a receiver is probably not a good source for the system. The input resistance of the CK99 amp is probably in the 10k ohm area, which isn't what power transistors are good at driving. Thge system is probably meant to be hooked up to a computer or blue tooth thingy. I'd suggest trying that.
And running everything off one channel is not going to get these speakers to their potential. You are right that the specs are ridiculous - in the 70s we thought it preposterous that some manufacturers still used peak to peak wattage measurements, one channel at a time, and sometimes only at a middle frequency, and worse, at 1% distortion. WE thought the RMS requirements that came in the mid 70s had cured that (even though they are based on power through a resistor, which is not much like the complex load of a speaker). Now we see even less justifiable claims - 30% distortion - WTF?
I suspect that no matter what you try, these speakers may disappoint you - they are probably mass market home theater products, aimed at making big impressive noises for those watching videos. Use them for that, but if you want music, look elsewhere.
 
I think the OP's speakers/amp are actually a bi-amped system, but in a rather dreck mass market boom and tizz fashion. Not something that's gonna be favored by many in the hifi crowd.

The factory amp appears to have hi and low outputs for each speaker.

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1. The power claims seem to be stretched extraordinarily, how much power could these speakers actually take?
Absolutely absurd claims. Hard to say what actual real world RMS watts they could take. But I'd bet that if I actually hooked them up to a 1,000 watt RMS power amp and cranked it to 11, they'd never be the same. Usually, a larger (10 or 12") woofer that can handle a really high wattage comes complimentary with a huge magnet on the back of the speaker. Bigger the magnet, bigger the wattage.

2. How could the amplifier do 1,250W RMS on 4 channels, yet have a power consumption of 320W?
Short answer: It doesn't. If it is a Class D circuit/amplifier, you get about 80% of the energy and will have lost 20%. 320W breaks down to 256W. There's a more realistic number for the "average" value. BUT - during transients (a drummer hitting the snare really hard) the amplifier can/could peak at a much higher value, but only for a microcosm of a second.

3. The JVC has a rated output power of 120W at 8Ohms, 0.007%THD with 2Ch driven. Would it be more power only driving the 1 channel? Sidenote : WTF 0.007% distortion!
0.007% THC at what db? The db part really counts. What if it's 0.007% at 50db. That's low talking volume. Definitely look a little closer at that spec. As per channels, I think that you are asking if you remove 1 speaker, does the other gain more power? If so, the answer is no. The wattage stays the same. Alternate version of that question - if you turn off Channel A and leave Channel B running, do you get more power. No.

4. If there is still lots of headroom left for me to put power into these speakers (If all the numbers LG claimed somehow aren't all fudged). Should I sit and wait until I hopefully find one of the original amps for sale and use that, or should I purchase a power amplifier that could line up with the needs of these speakers (ex. Behringer NX6000D which delivers 2 x 3000 Watts into 4 Ohms, 2 x 1600 Watts into 8 Ohms)?

I tried to hunt these down and I think I found them. Looks like a class D amplifier. They can be very powerful, as the amps convert energy at a high level. Often coming in small form. Personally, I wouldn't use a class D at all. But this is preference. I only use D for subs and/or recording as it can be a rather flat sounding amplifier. There's nothing like a good tube amp, but you'll need a lot of 6L6 tubes to get to 1,000 watts.

When getting into the watts idea... Keep in mind that most half stack guitar amplifiers are 50 watts, when you get the volume to about 4 the guitar player is already as loud as the drummer. Considering a snare drum puts out around 100 to 120db (if you really hit it), 50 watts was all that was needed. Sure, you can be my old bass player that brought in the 700 watt GK full stack rig. And then I have to put a -15db pad in place in order to tame the damn thing and actually be able to turn the volume up without blowing my ears out over a 1 degree change... :)

How's that JVC hanging in there? If it rocks, just go with it. I'm using 30 watts on a pair of Genesis Physics III's and I've never cranked it - as it would be far too loud.
 
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