Axiom Home Page Forums General Discussion Home Theater How much power do I need - m60 measurements

Rat one thing is for sure this thread has not convinced me to trade in my amp .

Your reply reminded me of Alans article, that's the reason for the link. I don't think you were to far off base.

John: my bottom line was that you could take a lot of liberty with my numbers and assumptions and easily come up with peak power requirements far in excess of 100 watts.

This is especially true for those who listen at levels at or above 90 dB SPL.

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Small correction. The receiver is rated 100W+100W, 2 channels driven

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Yes i slipped back into a thought on my own receiver which is rated at 100w/ch, but as all channels are driven, the reality is more like 70w+ per ch.
In your case, 100W + 100W would be a split.
Dual power supplies?
Dual mono design?
Or just a spec?

It seems like plenty of headroom, but push those dB into the 90+ range and watts consumed still fall under the max. rated spec yet distortion is created.
The paradox of it all!!

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3. Speaker impedance is not fixed across the spectrum (may dip from 8 ohms to 4 ohms or lower)

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Rat, this is something i briefly noted earlier as a variable unaccounted.
Gena measured the individual situation with the originally described setup so the numbers apply properly in this case. When deriving 'what ifs' for other situations then the idea is expanded just as you did and obviously an argument can be made in the second instance.
In Gena's example (or rather real world situation) this newly derived situation is moot.
However, it would apply to me since i own speakers (6ohm) that do dip to 4ohm, in a large room, and as such, i need a beefier amp for the SPL i use with this specific setup.
All i use is a receiver in my 5.1 media room though. The area is small enough (and speakers less demanding, more efficient) to attain the SPL i require. I've already setup my receiver to stop its volume increase before its distortion point is hit, plus a small safety margin.

How did you set up your receiver to prevent clipping?

By the way, what color is your 703? I bought silver.
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It's silver too

The receiver has a max volume setting to limit anyone from cranking up the knob to 100%. I set that limiter to 83% or 83 on an absolute scale of 100 which incidentally is the units' reference point. The receiver also has a limiter for subwoofer output as well but i leave that off/unlimited.
I've done some testing in the past and usually above the 90 mark distortion begins with my M60s (playback material dependant). As such, setting the unit to max at 83 means i always know it is well below a clipping point.

We tried a similar test with a friend's Tannoy S6s and an Anthem amp (225w/ch). We had the speakers hitting their excursion limits (only very briefly) w/o detectable distortion and at relatively low gain %s so we knew that his amp had more power than the speakers could consume. Hence, he really doesn't have to worry about distortion blowing his drivers (electrically caused damage), but he does have to worry about more direct physical damage to the drivers if he pushes them too hard.

I probably should have also asked what receiver do you have and is the setting internal or something that you can so external with your remote?

Ratpack,

If you're asking about Onkyo 703 it's done via remote control Setup==>Pereferences==>VolumeSetup==>MaximumVolume. By default it's set to OFF but you can set any level.

It also has another useful setting - the turn On level. By default it is set to LAST, and if the last night you're listening at 0dB and turn it back on at 6 in the morning... Well, your family is not going to be happy I set mine at -45 to provide a smooth start.

Regards,
Gena

I find this thread fascinating. I wonder what I am missing without separate amps, but I have no desire to pay for something that doesn’t do much for me.

Gena,

Unfortunately it seems like test equipment is specified just as aggressively as audio equipment. 250 us acquisition time is for repetitive peaks, 2.5 ms for single events, which is 1 cycle at 400 Hz. This is, of course, buried in a foot note of the extended specs. of the Flukemeter. It seems likely that musical peaks typically last longer than 2.5 ms anyway, so it does not matter. I have no idea, maybe someone who knows about the duration of musical peaks can comment ?

My receiver claims to handle 7, 120 W rms each channel 20 Hz to 20 kHz, with 0.04 % THD into 8 Ohms. Max. of 175 W with 10 % THD. Dynamic power 8/6/4/2 Ohms of 155/195/250/330 Watts (no distortion rating). It is not clear on how many channels this is for at the same time. I think it cannot be more than 2 since the unit consumes 500 W. Outlaw states “all channels driven at the same time”.

If my peaks are 24 X like what you have measured with Floyd, average could be 120/24 = 5 watts. If 240 is shared between 3 fronts then 3.2 W. I don’t believe it is playing at 95 dB undistorted. My room is a bit smaller than yours and fairly reflective.

As mentioned above things are material dependent, but I can play most things at a loud (rock the house or almost but not quite orchestra seat level for the other half) without distortion, but not extremely loud, approaching concert or live music in a small venue level. I am not an audiophile who listens to minute differences.

It gets down to personal preference and how much you want to pay but I definitely understand the case for more power, more so for an efficient speaker. But if for $ 1500.00 I get 600 W instead of 200 or 250 W across the front 3 I’m thinking it’s not worth it. That is only 4 or 5 dB, which is not even twice as loud.