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Home Theater => Audio => Tubes => Topic started by: qguy on Jul 04, 2019 at 11:41 PM

Title: Power output using different loudspeakers
Post by: qguy on Jul 04, 2019 at 11:41 PM
Speaker A, 5 way, 15 inch subwoofer, 12 inch woofer, 8 inch midbass, 5 inch mids, 1 tweeters, 8 ohms, 86 dB
Speaker B, 5 inch Single driver, 8 ohms, 95 dB

If the volume of the tube amp is at 9 position for both loudspeakers, is the tube amp working harder when using Speaker A ?

I know the concept of sensitivity where every 3dB difference requires twice the power, so there is no need to include this in your response
Title: Re: Power output using different loudspeakers
Post by: uvax on Jul 05, 2019 at 07:40 AM
No. Since both speakers are rated at 8 ohms they should be drawing roughly the same amount of power.
Title: Re: Power output using different loudspeakers
Post by: alvinbaronsia on Jul 05, 2019 at 12:13 PM
i think it depends on which driver has the lowest ohm dip...

Do you have impedance measurements?
Title: Re: Power output using different loudspeakers
Post by: meat_eater on Jul 05, 2019 at 12:38 PM
Depends on which speaker has a more linear impedance response. Assuming speaker A  has a roller coaster like dips and peaks, then A would be harder.

Now if A had a fairly benign load (like some Dynaudio), then A would be easier.
Title: Re: Power output using different loudspeakers
Post by: jeff29jeff2002 on Jul 05, 2019 at 07:32 PM
I agree with sir UVAX, the speaker impedance is what is being sensed by the amplifier as its load. The lower it is, the heavier load would it be for the amplifier.  The speaker draws the same power from the amplifier.

The sensitivity (db rating) represents another thing. It gives you an abstract picture of how a speaker produces sound pressure at a given power from the amplifier. The higher sensitivity (db rating) the higher sound pressure it will produce to speaker with a lower sensitivity rating at the same Power Output from the amplifier. In your situation, I would expect, Speaker B with 95db rating would produce more sound pressure than Speaker A at the same amplifier setting.

Unless, the real speaker impedance is not indicated, then the result would be different.

Just my theoretical expectations, let us know the actual result.
Title: Re: Power output using different loudspeakers
Post by: JojoD818 on Jul 08, 2019 at 08:33 PM
The answer to this relies on the impedance response graph of both speaker system.

This should go away after you had a few glasses of wine tho. :D
Title: Re: Power output using different loudspeakers
Post by: qguy on Jul 08, 2019 at 08:57 PM
Bwahahahaha


This should go away after you had a few glasses of wine tho. :D
Title: Re: Power output using different loudspeakers
Post by: tony on Jul 09, 2019 at 07:26 AM
power ratings in any amplifier is based on sine waves, after all there is no other way but to use sine waves....

but who listens to sine wave? no one..

so when listening to music, power ratings based on sine waves takes on another meaning, another dimension...

we have tested a 1000 watt power amp into an 8 ohm dummy load, but listening to real music on a real set of speakers, we could not push the amp to past 150 watts without hurting our ears....

so as long as you are able to get the spl you desire, there is no need to over think this...
Title: Re: Power output using different loudspeakers
Post by: tony on Jul 09, 2019 at 07:28 AM
here is another take, a tube power amp to me seems to be more powerful subjectively than an comparable ss amp of the same power rating....but this is just me...
Title: Re: Power output using different loudspeakers
Post by: tony on Jul 09, 2019 at 07:30 AM
I agree with sir UVAX, the speaker impedance is what is being sensed by the amplifier as its load. The lower it is, the heavier load would it be for the amplifier.  The speaker draws the same power from the amplifier.

The sensitivity (db rating) represents another thing. It gives you an abstract picture of how a speaker produces sound pressure at a given power from the amplifier. The higher sensitivity (db rating) the higher sound pressure it will produce to speaker with a lower sensitivity rating at the same Power Output from the amplifier. In your situation, I would expect, Speaker B with 95db rating would produce more sound pressure than Speaker A at the same amplifier setting.

Unless, the real speaker impedance is not indicated, then the result would be different.

Just my theoretical expectations, let us know the actual result.


i agree, it is not the power of the amp, but the demands of the speakers consistent with desired spl that determines what power is drawn from the amp...
Title: Re: Power output using different loudspeakers
Post by: tony on Jul 09, 2019 at 07:31 AM
Speaker A, 5 way, 15 inch subwoofer, 12 inch woofer, 8 inch midbass, 5 inch mids, 1 tweeters, 8 ohms, 86 dB
Speaker B, 5 inch Single driver, 8 ohms, 95 dB

If the volume of the tube amp is at 9 position for both loudspeakers, is the tube amp working harder when using Speaker A ?

I know the concept of sensitivity where every 3dB difference requires twice the power, so there is no need to include this in your response

speaker B is the easier load...
Title: Re: Power output using different loudspeakers
Post by: JojoD818 on Jul 10, 2019 at 07:55 AM
Too many takes...

Just carefully choose a good bottle of wine and this will all go away my friend...
Title: Re: Power output using different loudspeakers
Post by: tony on Jul 10, 2019 at 08:23 AM
that is the point jojod, just use them and enjoy the music.....cheers...
Title: Re: Power output using different loudspeakers
Post by: JoeyGS on Aug 15, 2019 at 03:57 PM
Kampay! ..... and everybody happy!