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Whats with the Watts ??

Hi everyone. I'm starting an audio system for the first time and I've been doing my homework -- reading and listening as much as I can. Sorry if I ask some dumb questions along the way...

One aspect I'm very confused over is how much power I need in an amp. So many highly rated amps seem to be in the 50 watt range, yet there are also those in the 100's of watts. My room is about 25 x 15 with a ceiling that slopes from 8 feet at one end to about 18 feet at the other end. The room has 3 walls but opens up into a foyer on one side. I listen to all types of music, but mostly blues, jazz, and some rock. I like to listen at low to medium volumes. Its rare that I would play very loud. If it's important to my question, I seem to prefer the sound of solid state amps.

Being uneducated on the subject, my initial thought is, get more watts. Better to have too much than too little. So my questions are; how many watts should I be looking for and is there something to be gained or lost with too much or too few watts? Thanks.
silver911
montytx
138 posts
 
The reason the speaker efficiency and sensitivity are paramount is because that determines how loudly they will play given 1 watt of power.

A simple example is that it takes an 87db sensitive speaker 1 watt of power to produce a sound pressure level of 87db at 1 meter. It takes a 90db sensitive speaker 1 watt of power to produce a 90db level at 1 meter and so on and so fourth.

In order to increase the sound pressure level 3db, it takes a doubling of wattage. 87db @ 1 watt needs 2 watts to produce 90db. It needs 4 watts to produce 93db, 8 watts to reach 96db, 16 watts to produce 99db....just keep going.

Keep in mind that this is measured at a distance of 1 meter for uniformity. The size of the room, the distance you listen from the speakers and the furnishings and layout will all impact the sound pressure levels reaching your ears.
silver911 OP
9 posts
 
I haven't purchased speakers yet, though I've listened to quite a few. The more I audition, the more difficult the decision becomes. Since the audio dealers in my area don't seem to seel the same brand amps, I can't tell if the speaker sound I like or dislike is more the speaker or amp.
rodman99999
6,160 posts
 
The idea that a doubling in volume takes twice the power is incorrect, but a common error. Our hearing is logarithmic, while the db or power scale is linear. It actual take 10X the power to produce what we hear as a doubling of volume. For more insight see: (http://www.audioholics.com/education/frequently-asked-questions/relationship-between-watts-and-dbs)
pubul57
3,712 posts
 
Impedance is just as critical to matching an amp to a speaker. Once you pick your speaker it will be easier to adise you on an amp. Choose the speaker first, it is most determinative of the general sound signature you will experience.
dave_b's avatar
dave_b
3,159 posts
 
Get a pair of Totem Forests and a Krell 400xi with a decent front end, sit back and be amazed!
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