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Simple methodology for dummies to measure power needed ?


Active Member
Nov 30, 2019
Rennes, France

I found that it is difficult to know how many watt of power I have need for my setup.

I try to image a simple method to measure it.

For me standard methods are weak to have good confidence :

- by computing: my speaker are 93db (really?) I want to listen at max at 90db(perhaps) but I have need 15db of crest , so my needed power is .... between 5W and 1000W (changing some parameters can bring very different results).
- sonometer: Ok for pink noise but we have to have a good sonometer , well calibrated (not an android app on telephone)
- If the amplifier have vumeter or clip led , you can also have weak indicator.

My method (not really tested but I can test it).

- Listen a a set of my own music on my system and try to reach the maximum acceptable level for my ears. (music should reach the 0db in files)
- without change volume configuration, play a tone (sinus) at 100Hz with level 0db
- with a volt meter, note the value V at the speaker

Previously , you have measure the resistance of your speaker at 100Hz

By computing, you can now have the number of volt needed by your amplifier.

Of course, the tone at 0db will be very loud, more loud that the louder music that you can support.
An advanced method is to play the tone at -20db and after to little computation to find the right value.

Ok, this is only some thoughts.... what is your opinion?
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