So how much power do you really need for domestic listening ?
 User Name Stay logged in? Password
 Home Forums Rules Articles Store Gallery Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read Search

 Solid State Talk all about solid state amplification.

 Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
 22nd March 2010, 06:26 PM #1 diyAudio Moderator     Join Date: Sep 2007 So how much power do you really need for domestic listening ? So just how much power do you need at home... the next time you are wondering whether to build that 500 watt monster amp. I recently got my hands on a sound level meter (C weighted) and was (pleasantly) surprised at just how low the levels were that I normally listen too. At the listening position around 70db (average level) is plenty for normal listening. The meter shows around 75db peaks (125ms response) So that got me thinking... if you have CD with test tones at 0db, a little experiment that's easy to do. You turn the amp up to what is the loudest you would ever normally listen on a music CD. Stop the CD and disconnect the speakers. Now play the test tone and measure the RMS voltage at the amplifier terminals. Make sure your meter reads AC accurately at the frequency chosen... probably around 100hz is best if your test disc has that. Disconnecting the speaker saves your ears and maybe even the amp as many may not like delivering a lot of power continuosly if the heatsinking etc is marginal. What does that tell us ? Well the fact the tone is recorded at 0db (make sure it is), means that that is the maximum signal you can ever get from the CD player. No transient in a music program from CD can ever exceed that level. It's cast in stone. So lets say the meter showed 10volts RMS. We will also assume an imaginary load of 8 ohm (because you actually measured with no load) for these calculations. We assume the amp would maintain it's output when loaded. So 10 volts RMS across 8 ohm is (10*10)/8 which is 12.5 watts RMS. That implies that an amp rated at that output would in fact deliver all you ask of it, cleanly and with no clipping. Following this reasoning my "ideal" target amplifier would be around 20 to 30 watts RMS. Once you reach that level then it takes a relatively large increase in power to get a "noticeable" increase in volume. A doubling of power gives a 3db increase which is not as noticeable as you think and certainly not twice as loud. With my speakers which are rated at 90db efficiency for 1 watt, that implies a max peak level of around 102 to 105 db. The average of course would be far lower, and not only that, these measurements are based on 0db or maximum output from the CD player being reached on music program which is unlikely. So what's your ideal power rating for an amplifier ? How loud do you really listen ? __________________ ------------------------------------------------------- A simulation free zone. Design it, build it, test it.
 22nd March 2010, 06:55 PM #2 diyAudio Member     Join Date: Feb 2006 Location: Hillsborough, NC/McLean, VA Totally depends on the speakers On big Altec multicells, you might not need more than a 45 triode amp on the horns...for full-size Maggies, you might need that pair of bridged Crown beasts __________________ Jim J.
 22nd March 2010, 07:20 PM #3 diyAudio Member   Join Date: Aug 2009 Location: North Texas, USA Don't forget that you need the headroom for the dynamics, not the steady state level. If your average is 70 dB, you can easily get 85-90 dB peaks so your power requirement may have increased by more than a factor of 10. __________________ I was so much older then, I'm younger than that now.
 22nd March 2010, 07:22 PM #4 diyAudio Member     Join Date: Apr 2007 It's like a delinquent raper , when you know he's gonna make it again ,he should be evirated not to get compulsed to do that again! Same for amplifier's power-ie listening levels- once you settle down and you know that you won't disturb anyone else like you did in the past (mostly with bad distorting amps )...well,it depends from many things : a certain power reserve might lift your mood sometimes ,you'll never know .... Bye
 22nd March 2010, 07:25 PM #5 diyAudio Member     Join Date: Nov 2003 Location: Budapest Fundamental question, what the neighbours say to all of this! Gyuri I pester you again already somewhere else, kind pico! You know it because I am an ugly, evil, bearded, bald little old man, who got drunk moreover yet,. no, because of that not so much after all. __________________ Those who would have deserved the life they are all dead already. "Oh, my dead dears!" - Captain Cat Last edited by Gyuri; 22nd March 2010 at 07:34 PM. Reason: Private message for a friend, excuse me.
diyAudio Moderator

Join Date: Sep 2007
Quote:
 Originally Posted by fastbike1 Don't forget that you need the headroom for the dynamics, not the steady state level. If your average is 70 dB, you can easily get 85-90 dB peaks so your power requirement may have increased by more than a factor of 10.
Yes... but those transients are set by the max output of the CD player (say 2v RMS at Odb) and the setting of the volume control at "your loudest" listening volume.
That's where the rough and ready meter and test CD comes in. At the highest volume I would ever use the peaks would not exceed 105db. They couldn't because that measurement is taken using a 0db test track which sets the max possible level.
__________________
-------------------------------------------------------
A simulation free zone. Design it, build it, test it.

 22nd March 2010, 07:31 PM #7 diyAudio Member   Join Date: Nov 2009 Location: algeria/france I use a 3 channel amp , 2 X 5W + 10W for the basses. My speakers s efficency is 90db/1W/1m.. This is vastly enough, even for loud listenings levels..
diyAudio Moderator

Join Date: Sep 2007
Quote:
 Originally Posted by wahab I use a 3 channel amp , 2 X 5W + 10W for the basses. My speakers s efficency is 90db/1W/1m.. This is vastly enough, even for loud listenings levels..
Exactly what I find. Your speakers are the same efficiency as mine too.

And I'm sure your ears appreciate it too...
__________________
-------------------------------------------------------
A simulation free zone. Design it, build it, test it.

 22nd March 2010, 07:36 PM #9 diyAudio Member   Join Date: Oct 2005 The method proposed is a nice one to get an indication of power requirement. However, not all CD's (which you would use to determine your comfort level) are recorded with the same level. You may therefore find that you like to listen to some CD's with the volume control at 11 o'clock, but others at 3 o'clock. This will give drastically different levels when you insert your 0 dB disc. Type of music, ambient noise, mood, etc may also influence your preferences. SveinB
 22nd March 2010, 07:46 PM #10 diyAudio Member     Join Date: Nov 2003 Location: Budapest I agree with the above one totally. The exact method would be the application of a sound pressure gauge otherwise, in the listener's distance and his head altitude. Everything else only misleading, and totally system pendant, including the neighbours. __________________ Those who would have deserved the life they are all dead already. "Oh, my dead dears!" - Captain Cat

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is OffTrackbacks are Off Pingbacks are Off Refbacks are Off Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post lineup Solid State 67 23rd August 2010 02:56 AM angeloitacare Multi-Way 14 16th January 2009 04:45 PM Eusebius Tubes / Valves 7 26th February 2007 02:09 PM marko Everything Else 8 28th November 2004 08:41 PM

 New To Site? Need Help?

All times are GMT. The time now is 04:52 PM.