Originally Posted by MoviesLover
First, my current system is a yamaha rxv-2095 powering a 5.2 system of M&K 4 ohm speakers:
1. Front Speakers = MK S100B -- 4 ohms & 50 to 200 Watts
2. Center Speaker = MK S125C -- 4 ohms & 50 to 200 Watts
3. Back Speaker = MK-95 -- 4 ohms & 50 to 200 Watts
4. Powered Subwoofer = MK 125 II
5. Powered Buttkicker system (under sofa) as a 2nd subwoofer
6. Panasonic BD 85 Blu Ray player
7. Sharp LCD (LC-60C52U)
8. The room is about 20' X 20' with 10' ceilings & i mostly use it for watching movies as low to moderate volumes.
QUESTION #1 -- I have gotten varying opinions about whether the 1120 has sufficeint power to do the M&K's justice. What do you guys think?
QUESTION #2 -- If i get a dedicated 5 channel power amp (eg emotiva xpa-5 with a rating of 350W/ch into the 5 channels at 4 ohms), would i be better off with this combination (1120 + emotiva amp) vs waiting for the the denon 4311 (and no separate amp)? The Denon should cost a little bit more than the combination above but have less power (at least on paper). Which would sound/look/be better?
QUESTION #3 -- i generally listen at low to moderate volumes so i am wondering if i even will hear the significant extra power from the emotiva amp (or denon upgrade) in the 4 ohm speakers that i have. In other words, is there a difference in sound produced by a relatively lower wattage power source (eg the pioneer 1120 on its own with its alleged 120 W/ch into 8 ohms) at low listening levels? i know that the emotiva (or denon) will let me play music louder w/o distortion but my question is whether massive power makes any difference in sound quality at LOW listening levels (and if so, why).
There are several things at play with your questions that I'll try to address.
1. The ratings of your speakers.
> Power handling vs efficiency. The spec that is most relevant in your case is the efficiency. Apparently you don't have that number available. The ratings speaker mfgs provide in watts (50 and 200 in this case) are generally just estimates of minimum recommended power input and max peak power input. But that doesn't tell you how loud the speaker will sound at a given distance and frequency with 1 watt input. IMO the 50 and 200 watt ratings in this case are pretty much useless. Recommend you google up some test reports on the speakers to see how they tested out for efficiency.
> Impedance rating. When a speaker mfg rates a speaker as 4 ohms, that does not mean the speaker has a flat 4 ohm, 100% resistive impedance. The actual load it presents to the amplifier output stage varies with frequency and contains a reactive component. That said, when a mfg rates a speaker at a nominal 4 ohms instead of 8, it's basically a heads up that you should be more cautious in selecting your PA. Two PAs with the same continuous RMS output rating into an 8 ohm resistive load may behave dramatically differently driving a 4 ohm or 2 ohm load. The PA must deliver proportionately more current at the lower loads, and this is where having a beefier supply and output devices capable of dissipating more heat becomes relevant. So if your signal happens to contain components at a frequency where the speaker reaches its minimum impedance and that's a really low value, and it has a transient and you have the volume up beyond a modest level, the PA could crap all over itself (technical term for becoming unstable and activating thermal protection). Ultimately the only way to determine with 100% confidence whether the PA and speaker are a good match is to test them together.
You might want to look at the upper end of NAD AVRs or their lower end PAs. They are designed to handle difficult loads.
Finally, if you know your speakers are relatively efficient AND you will never listen at higher volumes, you may be OK. I certainly wouldn't fit in that description. ;-)