Question. If I’m setting up a 5.1-channel speaker-system, must all speakers come from the same brand, with identical system specs, for ideal audio performance? What will happen if a 5.1 system consists of different brands like a small United Nations? Mine are all different brands but fortunately all are 8 ohms. Should I leave them alone or replace the right one(s)? Thanks in advance. –Jack
Answer. A note about impedance: You said “fortunately, all are rated at 8 ohms,” which suggests you believe all the speakers in a 5.1 surround system should have identical impedance ratings. Actually, that’s not true. There is no need to match the impedances of speakers in a surround system because each channel in a 5.1-channel (or 7.1) AV receiver has its own individual amplifier, so differing impedances don’t interact with each other. You could use a pair of 4-ohm speakers (the Axiom M80 v2’s, for example) as your main left and right front speakers, a 6-ohm center channel such as the Axiom VP150, and a pair of 8-ohm surrounds. The different impedances don’t matter, provided your AV receiver’s amplifiers can drive the lower-impedance 4-ohm main channel speakers without overheating. Impedance has nothing to do with sound quality. It is an electrical characteristic of a speaker.
If you want to have the most seamless, tonally balanced, natural-sounding surround-sound presentation, then, yes, ideally, all the speakers in a 5.1 surround system should be from the same manufacturer. The assumption is that when one engineer designs all the speakers, they will have similar tonal balance, which is determined by the overall consistency of frequency response–smoothness or “linearity” across the musical spectrum. It is especially important through the midrange frequencies where most vocal and instrumental energy is centered and where human hearing is the most sensitive to tonal differences.
The three front channels are the most important in terms of matching tonal balance. Axiom’s left and right bookshelf and floor-standing speakers, center channels and surrounds all have similarly smooth frequency response and timbre (tonal quality) so an all-Axiom system is the ideal. The surround speakers are less critical than the main front speakers and the center channel. You can “get away with” different brands of surrounds that may have differing timbre, but again the presentation won’t be as seamless. You may notice the surrounds more as individual speakers (surround speakers should not call attention to themselves).
You can use any brand of well-designed subwoofer so long as it has ample bass extension and good output for the volume of the room. Bass energy from a sub normally doesn’t have tonal colorations that offend because our hearing is most sensitive to tonal anomalies in the midrange.
In your case, for tonal consistency, I’d suggest you replace the three front speakers with Axiom M80 v2 towers for the left and right and an Axiom VP150 center channel. That way you’d get a front soundstage that has the same timbre (tonal balance) and a seamless presentation. You could assign your old left and right front speakers to surround duties and see how well they blend. If they seem to be tonally quite different from the Axiom front channels, then I’d save up for a pair of Axiom QS8 multipolar surrounds, which will deliver seamless tonal envelopment in the surround effects.