amp output

[thebutler007]

so.....my tv screen reads my 130 wpc denon 3808 is putting out -20 dB.....does that mean it is putting out 13 watts??

or is it -20dB from its reference level....(reference level not in spec)

I want to listen to what 1 watt into my RF-83 speakers sounds like per the klipsch spec.....don't know the recording level of the cd....that is probably necessary to know.....

comments??

[RNAVer]

I've been wondering the same thing. How do decibels relative to zero equal wattage output. Or do they.

[Guest " "]

dB level	power ratio	dB level	voltage ratio
-30 dB	1/1000 = 0.001		-30 dB	= 0.03162
-20 dB	1/100 = 0.01		-20 dB	= 0.1
-10 dB	1/10 = 0.1		-10 dB	= 0.3162
-3 dB	1/2 = 0.5 (approx.)		-3 dB	= 0.7071
3 dB	2 (approx.)		3 dB	= 1.414
10 dB	10		10 dB	= 3.162
20 dB	100		20 dB	= 10
30 dB	1000		30 dB	= 31.62

[DrWho]

The notion of "1 watt into a speaker" when using music as a source is a bit misleading. In fact, the entire discussion becomes much simpler when you just consider the voltage levels instead of the power levels.

The sensitivity of a speaker is the output measured at 1m when you have 2.83V at the input. This 2.83V would correlate to the amplitude of the sine wave. Music isn't just a pretty little sine wave - it's a bunch of sine waves added up together. Because of this, the measured voltage at the speaker terminals will be bouncing all over the place - making it impossible to really know what "1W" sounds like.

But if you wanted to get an idea with music, I would start by playing a CD that plays a single constant test tone. Pull out a voltmeter and crank the volume until the amplifier outputs measure 2.83V. At the point you'll know that the loudest parts in the CD will be putting 1W into the speakers.

If you wanted to try and calculate from specifications, I would find the max power capabilities of the unit and then find how high the volume dial goes (usually +12dB). Find how much attenuation in dB you need to bring the peak output down to 1W and then subtract that value from +12dB.

[Zen Traveler]

so.....my tv screen reads my 130 wpc denon 3808 is putting out -20 dB.....does that mean it is putting out 13 watts??

or is it -20dB from its reference level....(reference level not in spec)

I took for granted on my Denon AVR 4806 when I did the Audyssy setup, "0" was THX Reference level (which is louder than anyone would comfortably listen). I feel it would be similar in the AVR 3808. Fwiw, all of my speaker's gains are down between 5 and 9. I listen at 80-85 dB at my seat for most material. I can crank it an extra 5 dB comfortably. My Denon volume level is usually between -18 to -8 to achieve those levels.

[Guest " "]

if your speakers are 3 way, and say for example crossover at 500, 5000, the comfort level of tone testing to get to 2.38V could take on a different meaning at 250hz, 3000hz, and 9000hz for example.

Typically the low frequency drivers have a lower SPL rating than the higher ones do.  2.38V at 9000hz could be a pretty high SPL level on some speakers.   What frequency tone should you use and what would it really mean....who knows.

[DrWho]

Typically the low frequency drivers have a lower SPL rating than the higher ones do.

That doesn't matter when the passive crossover balances the acoustic output of the various drivers.