|
Speaker Asylum General speaker questions for audio and home theater. |
For Sale Ads |
Use this form to submit comments directly to the Asylum moderators for this forum. We're particularly interested in truly outstanding posts that might be added to our FAQs.You may also use this form to provide feedback or to call attention to messages that may be in violation of our content rules.
Original Message
RE: 4 ohms vs. 8 ohms
Posted by Presto on March 14, 2012 at 21:59:32:
Ah yes, the big "IMPEDANCE" switch. Now, don't QUOTE me on this...
But these impedances "switches" on amps do not TYPICALLY envoke some magical reconfiguration / bridging modes of amplifier output transistors to optimize for load impedance. I have heard it SAID that on some amps (especially HT receivers) that the switch simply engages a sort of current limiting circuit to allow the amp to drive the load, with some sonic penalty aka dynamic range compression, while preventing the amp from bursting into flames or melting into a puddle.
In fact, the existence of these switches does not instill confidence in me that the amp is very stable at lower impedances at all. Conversely, even some (admittedly top shelf) home theatre receivers can drive loads as low as four ohms with NO switch. Some PA amps are stable at 8, 4 and even 2 ohms - but many are fan cooled, so it's not a fair comparison to an amp that relies only on convection cooling with heat sinks.
So here is what you do. Give us the make and model of the speakers, and make and model of the amp. We can look at what size "cahonas" this amp has, and what the impedance plot of this speaker looks like if a camp like, say, Stereophile magazine has reviewed them.
Sorry for the long winded "non answer" but "buy them and turn it up slowly and see what happens" is something I do all the time and don't recommend to others! ;)
Cheers,
Presto