Axiom Home Page Forums General Discussion Stereo ok i'm confused....another M60Ti question

ok. i hooked up my Sansui B-3000 stand alone amplifier tonight, which is 140 watts rms per channel...440 watts total power on 4 channels. i would have thought that my speakers would be LOUDER now, but they are not. i figured the reason i had to turn my pioneer 1015tx up to -5 for happy listening volume was due to the loss of power from the receiver, or that it really was NOT 120 watts rms per channel in stereo...now i gotta wonder if it really is??? could it be that the axioms are just harder to drive than my older Infinity Reference 2000.6 towers??? i mean, my Infinities are a hell of a lot louder at -5 than these axioms are. am i the ONLY person here who listens to their music at basically reference level to be happy? there must be some secret of the universe that i'm missing here right??? please help me figure this out.

i was going to buy a 250 watts/channel amp, thinking i'd get better volume, but now i don't think i really would. what am i missing here???

The volume control markings (eg. "-5") are not a good basis for comparison. It would be nice if 0 meant something like "some kind of reference level output with a specified input" or "as loud as you should play without clipping" but different mfgs seem to do different things.

Yes this makes it hard to compare two amps. Regrettably I think that was the whole idea. A more powerful amp will play more loudly without clipping, compressing the signal, or otherwise changing the sound... and may give tighter bass as a result of lower output impedence... but if it ever was as simple as setting both amps to the same volume and comparing the outputs, it sure isn't that way today.

A big-ass amp is still a Good Thing.

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i hooked up my Sansui B-3000 stand alone amplifier tonight, which is 140 watts rms per channel...440 watts total power on 4 channels

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Are we talking a two channel power amp here ?

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A big-ass amp is still a Good Thing.

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The only thing Martha could have *possibly* added was the term 'honkerin' ... Yes, power is a 'Good Thing'.

And Oh BTW John, about that new avatar ... It's 'different'.

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A more powerful amp will play more loudly without clipping, compressing the signal, or otherwise changing the sound

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In my opinion, John is "DOBA" accurate in the post above, except that I would add that a more powerful amp will only enable the total volume to be a bit higher....not nearly as much as one would expect.

And now, we segue into JohnK to give us the exact formulas that descibe how much louder more powerfuil amps will be and how many watts you need to have to have a "doubling of perceived volume".

John?

>>could it be that the axioms are just harder to drive than my older Infinity Reference 2000.6 towers??? i mean, my Infinities are a hell of a lot louder at -5 than these axioms are.

That's just efficiency (sometimes called sensitivity) -- how much sound you get out of the speakers for a given amount of input power. Generally bigger speakers are more efficient than smaller speakers, but not always.

You can see this in the specs for Axioms and other speakers... here are the ratings for M3 :

SPL in Room1w/1m: 92 dB
SPL Anechoic 1w/1m: 88 dB

... and the rating for M60 :

SPL in Room1w/1m(dB): 93 dB
SPL Anechoic 1w/1m(dB): 89 dB

So... if you feed a 1 watt signal from a power amp into the M60 and measure the SPL 1 meter away in a typical room, you get a reading of 93 dB. Of course there is no such thing as a typical room, so the anechoic readings would be more useful... except a lot of manufacturers don't GIVE anechoic readings ;(

>>am i the ONLY person here who listens to their music at basically reference level to be happy?

No, but you are one of the relatively few who is allowed to do so

My first thought about the avatar was; "John really IS angry about what's been going on over at AVS"

>>And Oh BTW John, about that new avatar ... It's 'different'.

Sledge Hammer is my new hero. Is this pic better ?

Where are you getting this 440 watts total power on 4 channels from ?

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Sledge Hammer is my new hero. Is this pic better ?

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I don't know. I've always known you as the other avatar and the new is just different....in a couple of days I'll never know the difference.

It's almost like the guy you've known for years with a beard and suddenly he shows up out of the blue without it ... or like the nice looking neighbor lady friend of ours who comes over one day and things just weren't quite like the way they were yesterday and boastfully she ask 'How do they look?' Uh, GREAT! (That's actually an honest to goodness no-lie story!)

440 watts is what it says on the back of the amp.

That would be the input wattage, I would think.

Yep... power output to the speakers + power dissipated as heat (and possibly fan noise ) = 440 W.

Michael, forget the new amp bit. Your 1015 will supply the rated power, as it's legally required to do. A 140 watt amp would have about 0.67dB more capacity at momentary peaks than a 120 watt amp, e.g. 110.67dB compared with 110dB, which is insignificant. Your M60s use about 1 watt most of the time at a comfortably loud listening level and it's highly unlikely that even at momentary peaks more than about 100 watts would be used. Your 1015 is fine; relax.

it says it is rated at 440 watts right on the back of the amplifier...so that's where i guess

That rating is for input power, not output. Because amps are less than 100% efficient -- some far less than 100% -- 440 watts in does not equal 440 watts out.

I can see where reading the information supplied on the back of this particular amp can be a bit confusing.

that is not the output power, look on your freaking microwave or any other electronic that does not output audio, they all have a rated power. A computer has a rated power supply also, same diff.

Yep, right there...plain as freaking day.

Denons are excluded

Actually that's an H/K 635 but I suppose it could happen to the best of them.

I was trying to point out that *I* could see where reading the information supplied on the back of this particular amp would confuse an idiot like me ... and I'm not trying to say that Jinx is an idiot like me or anything, I don't think.

The good Lord knows I am when it comes to AV... I just know what sounds good to my ears.

AXIOM baaaaaaby

Although the wording on the back of the back of the B-3000 is a bit cryptic(e.g. what's "rated" mean), it apparently refers to power input, not output, as others have pointed out.

More generally, as has been discussed here before, if a wattage figure is shown on the back of the unit(not required)it will indicate an average power consumption figure unless "maximum", "full power" etc. is used. The UL testing requirement for safety reasons specifies all channels being driven at 1/8th of rated power for 1/2 hour without overheating and is ordinarily also used for specifying average power consumption, since 1/8th is considered about average. For example, a typical spec for a 7x100 watt receiver might be consumption of 450 watts(inciting claims of fraud from the uninformed). The UL test procedure would require running the unit at 12 1/2 watts per channel, about 87 1/2 watts total output. Although class AB amps operate at about 50% efficiency at full power, efficiency is far less at lower power levels and might be roughly 20% at 1/8th power. Therefore the 450 watts of consumption might allow around 90 watts of output during the UL testing procedure. The power consumption figure on the back would have relevance to the electric bill, but the rated FTC power output is the figure to look to for determining power capacity.