External amp and front soundstage timbre (1 Viewer)

[Martin Rendall]

I've read time and time again that it's best for all the speakers in your HT to match timbrally, for seamless audio panning. Makes great sense.

But what happens if you add a separate two channel amp for the mains? The point of adding the amp is obviously to improve the sound for the relevant speakers, but then won't that affect your soundstage? What if you bi-amp??

Thanks,

Martin.

 

[Martin Rendall]

Bump... Surely somebody will defend this practice!
Thanks,
Martin.

 

[Selden Ball]

Martin,

It seems to me that upgrading amplification shouldn't directly effect timbre, although a high quality amp should help soundstaging because of reduced cross-talk.

I think a lot of people add an external amp because most receivers are limited in the total amount of power they can deliver. e.g. 100W/channel but only 300 Watts total, limited by the power supply. By offloading some of the speakers, more power is available to those still being driven by the receiver. This results in more headroom all around before they start clipping.

Bi-amping spreads the load around even more. Since the lower frequencies tend to need the most power, offloading them can only help. How much it helps depends on the driver design, of course. Some woofers have quite low impedances and need hefty "high current" amps to drive them.

Also, by reducing the power each amp has to deliver, you can keep them in their more linear Class A modes. My understanding is that many amps are designed to run class A up to some relatively small Wattage, and run in a more efficient mode at higher power values.

 

[Arthur S]

Yeah, ideally all 5 or 7 speakers in your HT would be identical. Speakers make much more of a difference than amps. Any difference after adding an external amp is 100 times more likely to be the speaker than the amp. If you have a solid receiver, you may not notice a big difference adding an external amp. As Martin said though, it will take some of the burden off your receiver. Just don't set your expectations too high.

 

[Drew Eckhardt]

With the exception of amps having a non-negligible output impedance (tubes, transistors with a resistor in series with the speaker) and perhaps a slight roll off at the top end of the last octave, I don't think amps change the timber of speakers.

It's more a question of presentation (more fluid, detailed, etc) and imaging accuracy.

As far as the reason, I don't think it's more power for a given speaker because the effects are there even when you're seeing real peaks in the 1-10W range.