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 ?
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 ?
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
, 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
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.
Exactly what I find. Your speakers are the same efficiency as mine too.And I'm sure your ears appreciate it too...
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
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
Valid point
The method outlined does give a "worst case" scenario though. If you happened to choose a music disc at a "low" recorded level, and then used that to set your maximum listening level, then the power requirement shown by the test would be on the high side to what is actually needed.
Perhaps use a few discs or ones you know are recorded close to the maximum levels.
A good point.
And I'm sure your ears appreciate it too...
Agree , Mooly...
Anyway, more power will trigger the tympani s
compression mechanisms , making the ears
themselves less "hifi".
The size/shape of the room and all materials within will certainly have an effect on pwr needs and sound eq distribution . It is easy in a small room to get reverberations and that too will distort.
...now the challenge...to build an amp that has the capability of 200W but has a low enough noise floor that you can clearly listen to mW's of power.
...now the challenge...to build an amp that has the capability of 200W but has a low enough noise floor that you can clearly listen to mW's of power.
So we can live with an amp's SR of 1 V/uS ...
and
Mostly ,is what gives you full pleasure ,so we can endless speak on recording engineering ,of what was made to produce that sound and how it should be reproduced , regardless it is a synthesized "thump" or a clavycembal. And also the way you are sentimental towards a certain track:
if you played it always loud ,it should be always loud .
This can be achieved with 2 W amps and 96 dB speakers
and
is true but depends mostly on room size and the way it reflectes-absorbs the sound.
Mostly ,is what gives you full pleasure ,so we can endless speak on recording engineering ,of what was made to produce that sound and how it should be reproduced , regardless it is a synthesized "thump" or a clavycembal. And also the way you are sentimental towards a certain track:
if you played it always loud ,it should be always loud .
This can be achieved with 2 W amps and 96 dB speakers
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
I have the large Maggies. Every time I built a more powerful amp, they sounded even better. The last mono amps I built for them were 800W each. What I found most interesting was that with more power I didn't listen as loud as with less power, but it sounded better. In my opinion, you have enough power when you can't hear any difference with a more powerful amp.
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