Axiom Home Page Forums General Discussion Technical Questions Rec Spec Check

Hello!

I've used this setup for the past ~10 year with no issues for ~95% home theater use:

M80s v2 x2
VP150 v2 x1
QS8 v2 x2
EP500 v2 x1

With a receiver rated for:

"...
Continuous Power Output:
(20 Hz to 20 kHz, 8 Ohms, 0.08%)
Fronts: 110W + 110W
Center: 110W
Surround: 110W + 110W
Surround back (Front Height/wide): 110W + 110W

Continuous Power Output:
(1 Khz, 6 Ohms, 1.0%)
Fronts: 150W + 150W
Center: 150W
Surround: 150W + 150W
Surround back (Front Height/wide): 150W + 150W

Total Harmonic distortion: 0.06%
(20 Hz - 20 kHz, 100W + 100W, 8 Ohms)

120V 570W Power Supply
Canada Class B Digital Device
..."




1. Is this receiver properly driving my speakers to the best of their performance? or even near "average" performance?

2. If I buy a "better" receiver and listen at the same volumes I'm accustomed to, what will I notice in terms of improvements/differences in the audio experience, if any?

Thank you.

1. No. Yes.

2. Sounds like a mid tier receiver. A higher end receiver is capable of higher peak volumes before distortion. Good newer receivers employ sophisticated setup routines such as Dirac or Arc Genesis and modern sound formats like Dolby Atmos. Good examples are NAD and Anthem products. Denon also offers fantastic products with featuresets packed with value.

Apparently Onkyo now also carries Dirac, but not a fan.

I’d stay away from Sony for AVRs. Toooo basic in terms of setup flexibility.

Hi SCGM

I'm pretty sure that that first spec is a bit of an over statement the way it's being presented ... 570 Watts in ... yielding 950W out (if all channels are driven). More likely it's 2 channels driven ... that would be in line: 570W in giving 300W out ... it's about the right efficiency . Note that it's 1% distortion because they are driving it into clip to get it. BTW 1% distortion is almost impossible to hear but it's probably higher at other frequencies other than 1Khz.

Engineers and Marketers what to put their best spec's forward ... based on that I can make some assumptions:

using the 0.06% THD for 100W at 8 ohms to calculate the peek voltage (right at clip is most likely the place they'd get the best number). That gives me about 28.3 V rms ... which puts the rails at 40V.

Now how many speakers it can drive and how does it perform with a 4 ohm load (the M80s) depends on how much current it can supply. The best they could do THD wise is 133Watts at 6 ohms but, as I said above, they drove it into clip to get 150W. I'll assume that they picked 6 ohms (and not 4 ohms) because that was the best they could to current wise. Something between 4.7 and 5.3 amps ... call it 5 Amps/Speaker or 10Amps total.

with only the two M80's driven you'd get around 100W each but in reality
you have to share the 10 amps with the other 5 speakers.

I'd allocate 3 amps continuous to each M80's and split 4 amps between the other speakers ...
So my best guess is the M80s will get around 36W continuous with 113W for dynamic peeks ... once beyond that you'll be getting into distortion. BTW with highly dynamic music/sounds you'd only have 3.5W continuous as your limitation would be the 113W peeks ... But since you watch mainly movies and have a kick ass sub I would not sweat that ...

If that doesn't help I could put it into real world terms if you tell me how far you sit from the front speakers.



P.S. someone else might chime in if I missed something

My 5.1 setup is in a small room and seating is about 8.5' from the speakers

Since the receiver has met my needs, when I buy a replacement I'll look for one that meets/exceeds these specs but lists them properly for all channels driven so consumers don't have to guess.

Am I correct in thinking that if all else remains the same, the only thing more power does is let you go to higher volumes of sound?

Thank you for the feedback, greatly appreciated.

Doubling your amplifiers power (for ex. going from 100 watt to 200 watts) will only give you an additional 3dB of acoustic power.

dB Change Power change
+3 x 2
+6 x 4
+10 x 10
+20 x 100
+40 x 10,000

Let's look at a few numbers ... if your amp delivered equal power to all speakers ... each would get about 23.5 watts. More realistic, IMO, is 0.5Amps (2W) to each QS10 and distributing the rest to the front 3. Then the M80's and VP150 would get about 44.2Watts each. This is about as far as you can crank you system ... and the sound won't be overly great at this level (as we will explore below).

Let's look at the M80's in your system for three cases: 3.5W, 23.5W and 44.2W

M80 SPL = 94db 1W/1m (in room)
1W SPL at 8.5' or 2.58 meters = 94 - 20 log( 2.58 ) or 85.7 db
SPL at w = 85.7 + 10 log( w)
or for:

Now you’re probably sayin' "Wait a second" 44.2W v.s. 23.5W and it's about the same loudness? Yup, 3db is below most people's threshold to perceive a change in loudness.

Now here's the interesting part ... you're not going to perceive the difference in loudness but you probably perceive more harshness because you don’t have a lot of head room (about 6.5 db) and pulling more current will reduce even that.

On the other side 3.5W is plenty loud at your seat and your pretty safe from clipping. I can see questions coming:
Why? 3.5W seems like so little. Well, 1W is about where most listen to their music ... not loud but a decent level depending on your speakers and taste. 3.5W is a definite increase in loudness although you'd need 10W of power to double the perceived loudness (from 1W) ... i.e. 10x the power doubles the the perceived loudness.

To make maters worse you need 32x the continuous power you set to be fairly safe on clipping. So, 3.5 watts can reach 112W peaks. 10 watts 320W peeks. And ... that's one speaker .... Now start adding on more and you can see why some go nutzoid on power. Have fun.

I should add a couple of notes to the above …
I’m assuming your in a typically sized room … if your in a great room take off 3db or so

Movie theaters aim for around 80 to 100 SPL … that’s a range which balances hearing safety (keeping it under 85db) and emotional impact.
At 1W at 8.5ft your getting 85db (which is higher than I typically listen)

Live music is around 100-115db and rock concerts can hit 120

Thought of one more thing ... you might want to adjust the above numbers by +3db because the M80's are mostly playing the same content (i.e. you are doubling the power being poured into the room 100W+100W = 200W). I'd assume the VP150 is playing somewhat different content so I'd stick with +3db (but if all three were playing the same thing you'd adjust by +4.8db).

So, at 8.5 ft at

1 watt you'd get 88db and at
3.5 watts ... 94db ... which is in the jazz club level but to add more real world flavor ...
it's about how loud people crank their headphones or nightclub levels if you were sitting at the bar.

One more point with movies and hitting movie theater levels ...you're probably fine movie wise since
I'd bet you could get away with 10 watts continuous and hit the 98db level with tolerable distortion on the peaks ... plus depending on where (and how) you crossover to the sub you can gain significant power for the other speakers.

The real reason to upgrade is the point Trevor made ... technology moves on and upgrading your receiver gets you into the latest formats and room correction.

loads of number and an awful lot to digest.

But the other factor that i have yet to wrap my head around is the processor or pre-amp side of things. Let me explain what i mean by that.

you are buying an intergrated receiver in it combines both the pre-amp side that lets you select the source, control the volume and sends the sounds out the amplifier circuits inside the box. What everyone else has pointed out is the amplifier end of the equation that drives the speakers. How well they can drive the speakers and how much power realistically you are getting.

I have been in the music loving game for many years. I'm an old opinionated fart who cares more about the sound that I can hear rather than the theoretical math that backs it up. Experience has told me that all things being equal on paper doesn't translate to what you get and can actually hear. When you compare two different receivers to each other there are far too many variable things changing that you cant take at face value. I had a Nakamichi AV receiver that played wonderfully. The sound it produced was simply divine. Now on paper it had far worse specs that any of the more modern receivers that were built to work with modern equipment. The Nak didn't even have a digital decoder inside of it much less support of HDMI, so for a HT setup it was useless. So I bought other brands to try and replace what i liked and felt that they never quite sounded as good even though technically they had better specs.

I moved from relying on an integrated receiver to do everything for me. By pulling the amplifier out of the equation I removed just one more variable so i could decide what worked. I started with a Pioneer as they were relatively cheep and had the pre-outs I needed (some 8-10 years ago for a timeline). I was using at the time an Anthem MCA5 amp. it was a killer amp, but it never sounded all that good with the Pioneer plugged in. If I hooked up my speakers with the Nak using the tape outs to the MCA5 it sang. so i knew it was capable of giving the sound I needed.

I tried Sony, Merantz, Denon, Yamaha and each time I was not getting the same richness and sound that I wanted. Each sounded different from each other. But non sounded as good as what i had with the Nak. Eventually i bought an Anthem AVM60 pre-amp and just like that the sound i was wanting came through. A bit of a long winded story, but something to consider. if the pre-amp side of whatever you get just isn't outputting the signal in the manner and level needed, it doesn't matter the power and what dynamic range is available in the amp. CRAP IN - CRAP OUT!

Specs very often do not tell a full story. Actually, most times IMO specs are deceptive. You really have to be a fairly knowable to understand what’s being presented and more importantly what’s being left out. How many times have you seen a devices frequency response quoted as 20Hz to 20kHz. Well, that spec is meaningless without additional information. If they forgot to tell you its +/- 10db well some frequency’s may sound 4 times louder then others. Not quite what most would assume.

Even if they give you a complete quote it might not match the device you bought. This maybe from forgetting to update the manual/web page after a revision to just outright lying (think Chinese knockoff).

So when someone says X is better then Y because they read the spec … I take it with a grain of salt. That doesn’t mean specs are useless it just means you need to make sure they make sense, are interpreted correctly, and not take them as gospel.

In any case, putting specs aside, I can not tell you what your hearing. There are a lot of factors which can create poor sound … sometimes it’s exactly what you think it is … sometimes it’s not.