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Wattage vs. Volume

PostPosted: Tue Apr 07, 2009 12:51 am
by texas blues
Very interesting....check it out. For amp freaks both big and small.

Cheers, TB.

Re: Wattage vs. Volume

PostPosted: Tue Apr 07, 2009 2:02 pm
by maxx england
I'll believe that 5w in a building with shared walls is too much. I have my cheapnasty Tandy/Radio Shack 2w battery amp, and that's too much to play full on in our flat (admittedly concrete walls transmit sound beautifully, aided by the fact we're in a recognised quiet building (all over 40, know how to walk upright and chew gum at the same time). My 20w Chinky has to be on dead low, nearly silent, if I want to use it here.

Interesting about 30w only being 86% of 50w sound level though. Have been offered 30w Vox modelling amp for £75; unlikely to go for it immediately as I'm saving like hell for the entry fee for our first race meeting of the year, and there is a loaned Peavey coming my way from a very nice man.

Re: Wattage vs. Volume

PostPosted: Tue Apr 07, 2009 3:56 pm
by songdog
The other way of looking at it is that you have to double the power to obtain a 3dB (decibel) increase in loudness. So if at 2 watts your amp produces 95dB, cranking it up to 4 watts only gives 98dB. At this volume level 'most' people won't hear the 3dB difference. You'll need only 8 watts to get 101dB and 16 watts to get 104dB. 32 watts gets you 107dB.... are your ears bleeding yet, they should definitely be ringing.

You can work backwards too - 1 watts gives you 91dB, 0.5 watts is 88dB, etc. In a small room 88dB is loud enough that you would have to raise your voice to converse with another person in the same room.

Yep, IMO anything over 30 watts is probably a waste of electricity and money. If you do need more power, mic it through the PA.

Re: Wattage vs. Volume

PostPosted: Mon Apr 20, 2009 7:09 pm
by ricochet
The wild card is speaker efficiency. A 5W amp with an efficient speaker can easily be louder than a 100W amp with an inefficient one. Manufacturers of speakers give sensitivity figures, but different testing procedures and standards are in use so they're not all comparable, and makers of combo amps don't routinely provide sensitivity info. (You may be able to track down the info on the speaker in it, or not if it's a proprietary unit.)

Re: Wattage vs. Volume

PostPosted: Mon Apr 20, 2009 7:26 pm
by Ed Boyd
I have an old 1960's Fender Twin with 2 -12s. I think it is 85 watts. It can get pretty loud.

I have a 50 watt Mesa Boggie with 1- 12 and it will melt off your face. :lol:

Re: Wattage vs. Volume

PostPosted: Wed May 20, 2009 4:09 pm
by Randy G. Blues
Here's another interesting page on amplifier myths:

Re: Wattage vs. Volume

PostPosted: Sat May 23, 2009 1:42 am
by Sheb Whitebred
Just for yuks, this is from a post on my local Craig's List:

Marshall Valvestate 2000 AVT150 combo amp
- 4 channels (Ovd 1, Ovd 2, Clean, Acoustic Simulator)
- lots of flexibility to create different kinds of sounds
- comes with 4 channel footswitch
- 150 watts, can get very loud
- lots and lots of effects
- perfect condition - I have taken great care of it
- easily portable, great for gigs, dormrooms, bedrooms, basic recording, etc.

Um, yeah, a 150 watt amp is just what you need for a dormroom.

Re: Wattage vs. Volume

PostPosted: Sat May 23, 2009 10:41 am
by Bournio
Well the people I was living with I might do!

I learnt the wonders of driving amps hard then, just cos I needed to to hear myself!