I have these 2 pairs of speakers for a long time now. These were my initial speakers. They're sitting in my room for movies. I haven't tested them out on my Karaoke rig yet. I was just curious if they would do good for singing.

Using home speakers as PA speakers is like pulling a large trailer with a Honda civic. You can do it, but eventually something bad is going to happen.

To run speakers in parallel, use the following equation..

1 / R = 1 / Ra + 1 / Rb

Where R is your total impedance (what your amp sees), and Ra and Rb are the impedance of the two different speakers.

Substitute your speakers in, and you'll get

1 / R = 1 / 4 + 1 / 8

Making R = 8/3 or 2.667Ω

(Bet you wish you'd paid attention in math or physics class now).

Also need to make sure the amp is 2 ohm stable. I'm not recommending that you do it, it will probably sound terrible, as the 4 ohm speaker will get more of the voltage, but there's the theory to show what effect it will have on the amp.

Let it Rip,


I can't hook these up to 1 Amp? i'll have to hook them up to two separate amps?

Let it Rip,


I can't hook these up to 1 Amp? i'll have to hook them up to two separate amps?

Your last paragraph is what's important here (besides the fact that his amp is not specified for a 2 ohm load). The 4 ohm speakers have a lower power handling than the 8 ohm set. So you really need to know how much voltage they're going to see if you run that amp into them. This is where things get really complex since nominal impedance becomes almost irrelevant, it's usually just not worth the effort.

The speakers are not going to be good for singing - you can try. However if you MUST connect them both, i'd put 2 of the same speaker on 1 channel & the other 2 on the other channel - not recommended, but most amps today can handle a mismatched load like that. However again, you are very concerned with whether the speakers will be good for singing, no these will most likely be worse than even the JBL or Yamaha speakers you had tested - and those are designed for singing and PA use, not home theater.

Hooking up the 7200's in series with each other would present a 400 watt @ 8ohm load on a 500 watt @ 8ohm channel.

Whereas connecting the KLF-20's in parallel to each other would create an 800 watt @ 4ohm load on the other channel, rated for 950 watts @ 4 ohms.

Careful use/adjustments of the individual channels' gains should allow for non-selfdestructive sound

One concern I'd have with placing the 2 differently rated speakers on the same channel instead, is would they be reacting differently to the same gain being sent to them? Would increasing the volume enough for the 8ohm speaker over drive the 4ohm sharing the same channel; or conversely, would adjusting the volume for the 4ohm speaker leave the 8ohm too quiet?