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625FA required wattage?


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Here is just a very basic explanation. The 625fa has a sensitivity of 96dB, which means it's very easy to drive. If you put in 1 watt of power, the speaker will play at 96dB if you are sitting 1 meter away.  In order to raise the volume 3dB, you will double the power, so if you want to play at 99dB, which is quite loud, you need 2 watts of power.  If you are going to crank it to 102dB you will need 4 watts, 105dB is 8 watts, 108dB is 16 watts, 111dB is 32 watts, 114dB is 64 watts.  


Klipsch speakers have a very high sensitivity, so just a little power will get them very loud.  The average speaker sensitivity is 88dB, like the SVS Ultra Tower, so to reach 112dB it would take 256 watts.  Something with a sensitivity of 84dB would take 1024 watts to hit 114dB.  


In a home theater you are typically listening to movies at 70-85dB, and can have spikes up to 90-95dB.  If you really crank up your system you might be hitting 100-105dB at some points.  So even with sensitivity ratings of 84-88dB, you are typically not using a lot of watts at any one time.  On the other hand, the more speakers you have hooked up, the type of cable you are using, and the sensitivity of the speakers all put a drain on the receiver, lowering it's overall power output to each speaker.


There's a case to be made for people that decide to go for powerful receivers in the 125+ watts per channel range if they have big home theaters and crank up their systems.  The average user will be just fine with something even as low as 80-95 watts per channel.

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On 11/10/2020 at 11:14 PM, NinjaNick1 said:

5-10 watts? Saying theyre weak?



Mr. Paul used to say something like, "bragging about how much power your speakers need, is like bragging about how much gasoline your car can burn."  I remember when Blose used to brag that their 901s [gag] could be plugged into a 120V wall socket and survive the 3600 watts applied.  Assessing quality by the amount of power a speaker can absorb without bursting into flames is wrong and a fundamental misunderstanding of speakers. 


Better to brag (if that were really necessary) about how little power your speakers need (re: mpg) because that is a small indication of the low distortion levels they likely produce.  High efficiency means small cone movements that closely track the music without adding anything.



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