Safe to pair Emotiva XPA-3 with B&W CM8s + CMC?

D

dsheahan

Enthusiast
I have been auditioning a few amps to pair with my Yamaha 1060 and B&W CM8s + CMC to power my front stage (I have a powered sub as well). The two I have liked the best in my price range are the Outlaw 5000 and the Emotiva XPA-3 with the Emotiva slightly edging out the Outlaw.

While my Yamaha could power the speakers just fine for volume, the external amplifiers just do a better job of giving a bigger feel to music and keeping the sound tight and clean. In my demo songs things like drum hits, general bass, and vocals were much sharper, cleaner, and just felt more effortless.

The one potential worry I have is that the Emotiva is rated at up to 275wpc. The CM8s are rated at 150W RMS but also sometimes 150W peak depending on where you look. I don't anticipate cranking the volume much above -15db which means I will likely never really hit that full power draw, but should I worry about my speakers with this combination under my anticipated listening conditions?

I enjoy the sound out of the Emotiva enough that I could try going with their BasX line but that's a pretty significant power downgrade for their 5-channel version. The Outlaw sounded great but if both are safe I'd stick with Emotiva.
 
j_garcia

j_garcia

Audioholic Jedi
Not exactly sure what you are asking?

You will more or less NEVER draw full power from the XPA-3 period. You are using 5-10w average and 100W peak in nearly all cases. Unless you were pushing your receiver too hard, an amp will NOT make anything sound better; it just allows you to shift the distortion level higher before you hear distortion.

The wattage rating on the speaker is a maximum input level and if you did hit it, they would fry (indicating you are not using 150W). A speaker's wattage rating is almost irrelevant.
 
D

dsheahan

Enthusiast
So, that seems like a long way of saying "it should be fine"? I was pretty sure I wouldn't ever use the full power from the amplifier (as I had stated), and therefore never really approach the speaker's spec limits, but just wanted to make sure from some folks with more experience.

As for how it sounds, whether it's managing distortion or some other aspect of the amplifier/receiver/speaker pipeline, the difference in my A/B testing from song-to-song at my chosen volume was pretty noticeable both to myself and the smoke test of my wife (who would have been happy to tell me otherwise and not spend the money). /shrug
 
lovinthehd

lovinthehd

Audioholic Jedi
So, that seems like a long way of saying "it should be fine"? I was pretty sure I wouldn't ever use the full power from the amplifier (as I had stated), and therefore never really approach the speaker's spec limits, but just wanted to make sure from some folks with more experience.

As for how it sounds, whether it's managing distortion or some other aspect of the amplifier/receiver/speaker pipeline, the difference in my A/B testing from song-to-song at my chosen volume was pretty noticeable both to myself and the smoke test of my wife (who would have been happy to tell me otherwise and not spend the money). /shrug
So how did you conduct this A/B test?
 
D

dsheahan

Enthusiast
Basically I replayed the same song, at the same volume setting on the receiver, sitting in the same spot in my room and switching the cables to run the speakers directly from the receiver and then from the amp (and only plugging pre-out to amp in when using the amp). For this test I was only using 2 channels.

While it was perhaps marginally louder with the amp, it was more about the clarity and tightness of the speaker response that left me feeling the amp provided a better net result.
 
lovinthehd

lovinthehd

Audioholic Jedi
Basically I replayed the same song, at the same volume setting on the receiver, sitting in the same spot in my room and switching the cables to run the speakers directly from the receiver and then from the amp (and only plugging pre-out to amp in when using the amp). For this test I was only using 2 channels.

While it was perhaps marginally louder with the amp, it was more about the clarity and tightness of the speaker response that left me feeling the amp provided a better net result.
I wouldn't consider that a valid test...needs to be level matched....
 
D

dsheahan

Enthusiast
Is there a decent way for me to do that without buying additional equipment?
 
lovinthehd

lovinthehd

Audioholic Jedi
You ideally need an ABX comparator and someone to administer, but perhaps using two pairs of pre-outs, using different inputs on the avr fed from the same source (but would need to make sure they provide the same signal/level at the pre-outs) to the amps, and the outputs of the amps level matched, so you could have someone switch inputs on the avr without you seeing which amp is being used might be close enough. I seriously doubt it's worth the exercise.
 
D

dsheahan

Enthusiast
Between the two external amps there was frankly very little noticeable difference, if any. For some reason I can't explain I leaned towards the Emotiva.

The noticeable difference, to me, came when I was switching between direct-from-receiver and either one of the external amplifiers. So switching pre-outs doesn't really help me here.
 
lovinthehd

lovinthehd

Audioholic Jedi
You're relying on sighted sonic memory (you're aware of which amp you've hooked up and you're not doing instantaneous switching let alone matching the outputs of the amps), not a good way to compare. Within their specified operating parameters the differences will be extremely minor and not worth fretting over. You say the volume is fine with the avr, you may not even need an amp really, but may depend on the spl levels you're using.

ps If really wanting an amp, nothing wrong with keeping the one you "like" better, whatever the reason.
 
j_garcia

j_garcia

Audioholic Jedi
I bought my XPA-3 when I had 4 Ohm speakers. I now have all 8 Ohm speakers again but kept the amp (have to now, pre/pro only lol).
 
D

dsheahan

Enthusiast
Most of my desire for trying an external amplifier stems from a couple places:
(1) My receiver is rated at 110wpc/2ch. I'm a little worried that in 5-channel it will dip down around 70-80wpc (Yamaha RX-A1060)
(2) While that number may generally be fine, a number of things I read say that the B&W CM8 speakers are a bit power hungry and hard to drive, so my worry was that in a 5-channel setup, they may not get enough power to really drive the speakers to their full potential in terms of control.

I didn't want to spend hundreds on features I didn't need stepping up the receiver line for very marginal power gains so decided to try the external amplifier route and just audition a few to see if there was a difference I could perceive.

I actually went in somewhat skeptical but wanted to know for sure rather than always wondering what-if. I will likely try my A/B test again (however sub-optimal) by giving the receiver a little more volume when not using the external amp to make up for the amps additional reserves. I know this is clearly not a bulletproof test but we'll see what happens. I definitely wouldn't mind redirecting the money from the amp to something like a better sub or stronger center channel if the baseline audio quality isn't being improved.
 
D

dsheahan

Enthusiast
"I bought my XPA-3 when I had 4 Ohm speakers. I now have all 8 Ohm speakers again but kept the amp (have to now, pre/pro only lol)."

One bit of information here, from the Audioholics CM8 introduction page awhile back:

One small nit to pick with B&W, however (and to be fair, they are certainly not alone in this): There is a sticker on the back of each woofer magnet that clearly says “8Ω.” Since the two woofers are driven in parallel, that means the woofer section is 4Ω. The midrange and tweeter also carry “4Ω” markings on the back. This is obviously, intentionally, a 4Ω system, in spite of the factory’s specs saying “8Ω.”
http://www.audioholics.com/tower-speaker-reviews/b-w-cm8-speaker/b-w-cm8-introduction

Perhaps this is part of the situation? My receiver let's me switch to a 4-ohm mode, though I'm not sure if that's per-channel, would need to look further. Perhaps that can help?
 
j_garcia

j_garcia

Audioholic Jedi
It wouldn't matter that the woofers are 4 ohm individually, it is the total load presented to the amp. I'd expect that to result in a somewhat harder to drive speaker though. The 4 Ohm/8 Ohm switch should remain on 8 per Audioholics recommendation. I had a very beefy receiver when I bought my 4 Ohm speakers and it didn't like it at elevated levels, but all my speakers were 4 Ohm too. Amp for the front 3 alleviated that.

NOTE: Some Receivers have an impedance selector switch. In most cases we recommend the 8-ohm or more setting. The manufacturer puts them there for UL/CSA approvals as well as easing consumer concerns about driving low impedance loads. These switches step down voltage feed to the power sections which will limit dynamics and overall fidelity. Keep the switch set for 8 ohms regardless of the impedance of your speakers and ensure proper ventilation of the Receiver.
http://www.audioholics.com/frequent-questions/connecting-4-ohm-speakers-to-an-8-ohm-receiver-or-amplifier
 
D

dsheahan

Enthusiast
My listening test was at 8 ohms, didn't really want to mess with it. Maybe the above description is where my receiver was struggling a little bit versus the external amp? Again, I need to go back and listen a bit more, trying to give the receiver a better shot with maybe a slight volume bump. This kind of stuff is why I wanted to audition in person. My receiver isn't slouchy, but everyone's description of beefy can vary!
 
lovinthehd

lovinthehd

Audioholic Jedi
My listening test was at 8 ohms, didn't really want to mess with it. Maybe the above description is where my receiver was struggling a little bit versus the external amp? Again, I need to go back and listen a bit more, trying to give the receiver a better shot with maybe a slight volume bump. This kind of stuff is why I wanted to audition in person. My receiver isn't slouchy, but everyone's description of beefy can vary!
If using external amp your listening test was whatever your speakers demanded, not the stupid avr limiter setting which only applies when using the avr's amps....which isn't a restriction to 8 ohm in any case....
 
j_garcia

j_garcia

Audioholic Jedi
My listening test was at 8 ohms, didn't really want to mess with it. Maybe the above description is where my receiver was struggling a little bit versus the external amp? Again, I need to go back and listen a bit more, trying to give the receiver a better shot with maybe a slight volume bump. This kind of stuff is why I wanted to audition in person. My receiver isn't slouchy, but everyone's description of beefy can vary!
My beefy receiver was 42lbs and benched an actual 92WPC of a rated 120WPC. I'd call that beefy enough, but not enough for five 4 Ohm speakers in a large room. And these were true 4 Ohm speakers dipping to 2.6 Ohms min, but moderate sensitivity at 91dB.
 
Pogre

Pogre

Audioholic Slumlord
I was convinced I needed more power and was guided into upgrading my subs instead. I do not regret listening to that advice. to really gain anything significant by stepping up in power you'd have to double that which you currently have for a 3 dB gain, which isn't a lot.

the subwoofer upgrade cleaned up my system a lot more than I expected. I don't know what you're using, it might be a great sub already, but I suspect your money could be better spent elsewhere. maybe a second subwoofer?
 
j_garcia

j_garcia

Audioholic Jedi
A +3dB gain is very noticeable. It represents 50% increase in volume (that's why the -3dB point of a speaker is used as a spec), but as mentioned to achieve that requires twice the power. The reality is people think an amp will improve the sound significantly, somehow making their speakers sound different. It is usually a speaker upgrade that fixes that. Often a sub upgrade is recommended here too as that is frequently the weak point in many systems and upgrading to a better one (or two) is well worth it.
 
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