I have 4 loud speakers, 2 of them are 8 ohm and 2 of them are 4 ohm, if I plug one of the 8 ohm and one of the 4 ohm together on one channel of the poweramp, what will my ohm load be. Thanks.

2.66 ohms.

Good article with one hitch: running an amplifier in bridge mode with a 4 ohm load is the same as running a 2 ohm stereo load. Both electrically and thermally as far as an amp concerned, they’re the same thing to the output stages and the power supply. Each amp channel ‘sees’ a 2 ohm. The ‘virtual center’ of the load is midpoint of the load. So if you have say a 4 ohm sub or group of subs who’s aggregate impedance is 4 ohms, each amp channel is driving a load with half of the total impedance. So to more or less advocate running bridge mode for more power but then to discourage 2 ohm stereo use doesn’t make a whole lot of sense since there’s no difference.

Also FWIW, I’ve run many, many amps in 2 ohms stereo/4 ohms bridged hard for years without ill effect. Granted, they’re top of the line models with proper thermal design as to mitigate the high heat generation of low impedance loads. I guess that’s the key - don’t buy cheap crappy amps if you plan on using them to their limits. There are a of amps I wouldn’t trust for any long term use under those condition though the specs rate them as such.

Good article. However, I think someone should really address the fact that the main limiting factor for audio amplifiers, and their quality, is how much voltage can they swing and how fast can they swing it? Since, for complex waveforms, these are voltage gain amplifiers and not a constant draw power-supply.

Hi guys, 

I came from the mobile market of 20 years past and I am curious if the amp manufacturers have ever designed a Tri Mode amp? This is where you can run mono and stereo at the same time using just the two channels. Most subs have a crossover in them and you could passive crossover the mid / high cabs.

This was an eyeopening info for me and it will help alot in understanding nd rigging up a sound system in future.Thks a lot.If only u could recommend some brands of amp nd speakers which r good for specfic high load useage.

@Joseph: that’s a pretty broad question. Personally for “high load usage,” I’m a big fan of L’Acoustic K1 boxes with SB28 subs driven with their LA8 (Lab Gruppen) amps. But at over $12,000 a speaker not counting amps and a minimum 1 million dollar buy-in into their pilot program, I suspect that’s not what your talking about. Care to give more details on your application and budget?