Back in 1972 I bought my first car...used of course. A 65 Falcon. Wish I still had it. I installed a cheapie AM/FM cassette deck in it that was rated about 5 watts per channel RMS. I had seen ads for decks rated at >300 watts. My older U.S. Army missle electronics brother told me that 5 "real" watts is enough to make ya deaf. Fast forward 50 years to today and my vintage home receiver that puts out 54 watts per channel RMS continuously at 20-20kHz. I just had it rehabbed. It sits in a typical living room with curtains and carpets and furniture. My Polk speakers are rated at 20 to 275 watts, sensitivity is 91 and sitting about 8-10' from my ears. While the receiver was getting rejuvenated, I looked at ads for the vintage stereos, mostly Marantz, Sansui and Pioneer. Some of their RMS output ratings are way up there. All this leading up to the question...assuming the speakers are compatible with the receiver they are hooked to, why would I need 150 watts RMS per channel, or more, when I only have to crank my SX 828's (54 rms) volume up to 1/3 of the way to max to get music so loud it is uncomfortable to listen to, with no distortion? Or at least none that I can hear. I was once told that "more power" means less THD at higher listening levels. Is this true? How many real watts does it take to produce enough sound to deafen you while sitting 8' from the speakers? I'm more into the quality of the music than raw horsepower. I guess I could buy a dB meter. But again, how many dB's will it take to split my eardrums? Just curious. Am I boring you?
Watts...Uh the deal? ( Apologies to Pink Floyd.)
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swechsler
Frog Whisperer
5 acoustic watts is enough to deafen you. 5 electrical watts, not so much, at least not in most situations. To put this into perspective, a full symphony orchestra can probably create 1-1.5 acoustic watts. Figure most loudspeakers are about 1% efficient, so 5 clean electrical watts would translate into .05 acoustic watts.
But we generally talk about sound level in dB, not watts, because it's more relatable with how the human ear perceives sound. The dB scale is logarithmic. A 3dB increase in sound, which is considered to be just "noticeable", requires a doubling of the power. A 10dB increase, considered as "twice as loud", requires 10 times the power. And here's the thing: you'll never listen at your amp's maximum power. Unless your musical preference is sine waves, music has peaks, which require significantly more power (see the dB scale that I just mentioned, and here's a chart that gives some comparable levels). If you were listening at your amp's maximum output power, you'd be hearing close to 100% distortion. And while speaker efficiency is low, it still doesn't take a lot of power to create a satisfying sound level. If you had power meters on your amp, you'd see that the majority of the time, your power output is significantly under one watt. But most meters can't display peaks, so you won't really see the amount of power you actually need.
A couple of other things to keep in mind: your receiver's volume control is not wholly related to the amount of power it puts out (that is, the higher the setting, the more power it's going to produce, but it doesn't mean that at the 50% position you're putting out 50% of the power). This is for a number of reasons, including the dB scale. Also, max input power ratings on consumer speakers are essentially meaningless. There is no standard for them, and they can for the most part be ignored; you can safely drive a set of speakers rated at 50 watts with a 100 watt amplifier, you should just turn it down if you hear anything amiss (and again, refer to the dB scale, and even if the speakers are rated at only 50 watts, they can probably handle much higher peaks).
But we generally talk about sound level in dB, not watts, because it's more relatable with how the human ear perceives sound. The dB scale is logarithmic. A 3dB increase in sound, which is considered to be just "noticeable", requires a doubling of the power. A 10dB increase, considered as "twice as loud", requires 10 times the power. And here's the thing: you'll never listen at your amp's maximum power. Unless your musical preference is sine waves, music has peaks, which require significantly more power (see the dB scale that I just mentioned, and here's a chart that gives some comparable levels). If you were listening at your amp's maximum output power, you'd be hearing close to 100% distortion. And while speaker efficiency is low, it still doesn't take a lot of power to create a satisfying sound level. If you had power meters on your amp, you'd see that the majority of the time, your power output is significantly under one watt. But most meters can't display peaks, so you won't really see the amount of power you actually need.
A couple of other things to keep in mind: your receiver's volume control is not wholly related to the amount of power it puts out (that is, the higher the setting, the more power it's going to produce, but it doesn't mean that at the 50% position you're putting out 50% of the power). This is for a number of reasons, including the dB scale. Also, max input power ratings on consumer speakers are essentially meaningless. There is no standard for them, and they can for the most part be ignored; you can safely drive a set of speakers rated at 50 watts with a 100 watt amplifier, you should just turn it down if you hear anything amiss (and again, refer to the dB scale, and even if the speakers are rated at only 50 watts, they can probably handle much higher peaks).
There have been endless horses beaten to death on this one. Bob Carver of Phase Linear fame wrote an article making the case that people needed a 300+ watt per channel amplifier for proper music reproduction to ensure proper headroom. I'm sure it was totally unrelated to the fact that he was selling a 350 watt per channel amplifier at the time.
so on paper you could make the case for needing massive power despite using very little of it on average. In reality, if it sounds good to you, you probably don't need more. I'm currently running a pair of mono amps good for 90 per channel into what sounds like similar spec Polks and it works fine. I can swap to a 30 watt per channel amp and it also works just fine. The 4 watt amp doesn't quite cut the mustard but I could probably get by with an honest 15 per channel.
so on paper you could make the case for needing massive power despite using very little of it on average. In reality, if it sounds good to you, you probably don't need more. I'm currently running a pair of mono amps good for 90 per channel into what sounds like similar spec Polks and it works fine. I can swap to a 30 watt per channel amp and it also works just fine. The 4 watt amp doesn't quite cut the mustard but I could probably get by with an honest 15 per channel.
RunOutGroove
Addicted Member
Depending on other variables it seems that beyond more volume at lower distortion, you may just get a fatter sound out of an amp with more watts, everything else being the same. You might hear that as a fatter, tighter bass sound...
I don't have a really big listening room, and my speakers are relatively efficient, so I don't really need a lot of watts. 125wpc has always been more than enough for me. And 250wpc is only going to be 3dB louder, at maximum volume. It therefore becomes more about the quality of those watts, and getting a good quality signal out to a set of speakers that can make the most of it. There are, literally, millions of ways to do that.
But, as for why the need for more power? In most cases, the answer is headroom. But, it also depends on the amp, the speakers, and the room, and how they all interact. Some inefficient speakers in larger rooms will likely need more power, thinking Magnepans here. This is also when we start looking at high current capability in the amp design. But, the fact is, most people will never come close to maxing out their system's volume potential for more than a few seconds at a time. Unless you're bottoming your woofers, or replacing tweeters with distressing regularity, you're probably overthinking this. Relax, and enjoy the music.
But, as for why the need for more power? In most cases, the answer is headroom. But, it also depends on the amp, the speakers, and the room, and how they all interact. Some inefficient speakers in larger rooms will likely need more power, thinking Magnepans here. This is also when we start looking at high current capability in the amp design. But, the fact is, most people will never come close to maxing out their system's volume potential for more than a few seconds at a time. Unless you're bottoming your woofers, or replacing tweeters with distressing regularity, you're probably overthinking this. Relax, and enjoy the music.
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wmgwizard
Addicted Member
Good watts are better than many watts but MANY GOOD watts are the best.
It's all about headroom and the fact that music is dynamic, there are quiet parts and there are loud parts. Symphonic and orchestral music tends to be more dynamic than heavy metal.
While you amp is humming along with a quiet part using 2-3 watts of power when a transient hits it could require 20-30 watts or more. So in this instance your 54 watt amp should have sufficient headroom to avoid clipping. But let's say one night you are playing your music louder than normal, say 10 watts during a quiet part, when a transient hits you may need 100 watts to reproduce that transient. Many times this happens in an instant and lasts about as long and you and your speakers won't necessarily notice. However, if that transient lasts a few seconds or more causing your amp to clip then you run the risk of damaging your speakers.
It's all about headroom and the fact that music is dynamic, there are quiet parts and there are loud parts. Symphonic and orchestral music tends to be more dynamic than heavy metal.
While you amp is humming along with a quiet part using 2-3 watts of power when a transient hits it could require 20-30 watts or more. So in this instance your 54 watt amp should have sufficient headroom to avoid clipping. But let's say one night you are playing your music louder than normal, say 10 watts during a quiet part, when a transient hits you may need 100 watts to reproduce that transient. Many times this happens in an instant and lasts about as long and you and your speakers won't necessarily notice. However, if that transient lasts a few seconds or more causing your amp to clip then you run the risk of damaging your speakers.
BilboBaggins
Addicted Member
I happen to belong to the school that likes headroom. While I would like more, my results right now are pretty good. The deciding factor is how well you hear and if distortion bothers you. I tend to hear distortion quite easily. From the time I was 14 years old, there were certain songs that my equipment at that time couldn't reproduce without going into distortion if I listened to it at decent listening levels. An example was Carpet Crawler from Genesis - The Lamb Lies Down on Broadway. I saw Genesis numerous times as they were one of my favourite bands, so I had heard what it should sound like live. My systems couldn't do it until about 8 or 9 years ago. This didn't happen with most songs, but if the ones you really love are like that, you can get very frustrated.
I have 450 watts going into my Kef 107s. I do hear some distortion during certain classical compositions, but rarely with other music, at least when I am listening at normal listening levels. I rarely see my meters go above 3 leds. Four leds are even more rare!
I suppose it all depend on what you, as the listener, likes. If you don't hear distortion that easily, consider yourself lucky. My hearing led to a lot of expense and frustration over the years. Thankfully, I found my happy spot and all is good now.
I have 450 watts going into my Kef 107s. I do hear some distortion during certain classical compositions, but rarely with other music, at least when I am listening at normal listening levels. I rarely see my meters go above 3 leds. Four leds are even more rare!
I suppose it all depend on what you, as the listener, likes. If you don't hear distortion that easily, consider yourself lucky. My hearing led to a lot of expense and frustration over the years. Thankfully, I found my happy spot and all is good now.
A lot but not all vintage receivers had a sweet spot between 50-80 watts that’s where you had the best compromise between good sound and power ! A lot of the say 120 watt or more had plenty of power but had a harsher more clinical sound not as much finesse as their lower power siblings ! Below 50 wpc some had a nice tube like sound but somewhat limited on speakers I’m sure this no longer applies with higher end components or some newer gear
RVT1K
Super Member
My system behaves the same way with a minor difference, it happens when Metallica's cover of Stone Cold Crazy plays.
twiiii
Lunatic Member
Your dial may turn up and down the volume but it does not indicate how much power you are putting out. Thats a function of how much voltage you are putting in from your sources or how the tuner section is calibrated to the pre-amp section. Normally 12:00 clock on the dial is unity gain. Where what comes in eqauls what the pre-amp section is putting out to the power amp. So if your phono cartridge or CD player is putting out maximum voltage then you could easily be driving your amp into distortion with the 12:00 setting.. So why does the dial need to go past 12:00 . Well some times recordings are recorded at lower levels or you are trying to reproduce a compromised recording and you need to turn the knob past 12:00 to get the desirable normal listening level you are used to now. But modern technology has basically solved those low level issues, but the practice is still carried on to this day.
Back in the day when we used to calibrate our systems we would set the volume control on our pre-amps to 12:00 on the dial and then advance the input volume controls on our power amps to a level just a tiny bit above our preferred listening level. This would allow for a greater range of adjustment on the volume control. It also calibrated the loudness control switch function and made fine adjustments at lower levels easier on the dial . But integrated amps and recievers took that capability alway from us.
Now as why to more power. Well there are many different answers to that. Smaller speakers require the woofers to move further to reach lower frequencies and means you need more power because the voice coil has to be longer and the magnet structure longer, too. Making the woofer less efficient, So smaller woofers and speakers maybe more practicle but they require more power. Some people don't like the sound of blaring horn speakers. The horn acts as an acoustic amplifier. Remove the horn and you need more power to reach the same levels as before. Some time more than 10 or 30 times more power. Speakers in sealed tight enclosures, the back wave is being used as a spring would be to make the cone movement more linear, but that back wave puts resistance to the cone and that makes the speaker even more in-efficient. So you might need 4 to 8 times more power again. Then their are paneled speakers using magnetic fields and thin
wires attached to large sheets of plastic to generate sound. They require 400 or more times the power of large horn loaded speakers.
If you go to a live Symphony concert and sit about 30 feet away from the conductor the peak sound levels run around 104 db . Now you can reach that level in your home with a very large Horn loaded speaker with less than 1 watt feeding each speaker. Average speakers today with a listening distance of 10 feet will require about 100 watts per channel to reach those authentic live performance levels. But most people only listen with average recording to 85 db. So thats much less or about 3 watts to each speaker. Aren't we fortunate. But if you listen to classical music that hasn't been over processed you might need 30 watts for each speaker for short instantaneous peaks. This is probably your situation. But if you listen further away each time you double the distance you need 4 times the power. I listen at 16 feet so I would need at least twice as much power as you do. My speakers our 5 to 6 db less efficient than yours so that means 4 time more power. So in my case I need 8 times the power you do, and because every once in a while I want to listen at full concert hall levels that means I need another 40 times more power than you do. So while you may never need more than 3 or 4 watts to keep you happy and you only listen to average recordings I might need 600 watts to each speaker in order to reach concert peak levels. But thats rarely the case. 30 watts per channel is all I really need 95% of the time. But I have over 700 watts a channel just in case I do want to listen at the levels of a live concert at 30 feet.
Now my fathers old friend and classmate Paul Klipsch made his measurements 3 or4 feet behind the conductor and there fore said for authentic sound reprodduction your system needs to be able to produce 114 db of sound level. Well thats requires 10 time the power of the 30 ft distance. So only a horn loaded speaker can produce those kind of levels with reasonable amounts of power. At 10 feet listening distance about 50 watts per speaker. Your speakers would require over 40 times that much power or 2000 watts and mine about 8,000 watts. Well thats not going to happen thank goodness. Then you ask why most musicians having hearing issues? Doesn't matter if they are classical, Jazz or Rock and roll musicians. Anything over 85 db for more than 4 hours and your hearing is going to suffer. Then every time you increase the levels above that the time of exposure drops significantly. Fortunate for us music has large changes in level from very soft to very loud in most cases. Its only been since the advent of sophisticated recording manipulations and the advent of rock and roll that the sound levels remain fairly constant for long period of time. Thats why Rock and Roll along with disco and its over emphasized highs can be danger to our ears.. Of course riding a motor cycle with straight pipes or using a table saw or shooting a shot gun with out hearing protection can instantly compromise your hearing for the rest of your life. Ever try to replicate the sound of a steam engine passing or a dragster going down the track with your sound system. First of all, it can't, so don't even try. Movie theaters with all their sound equipment capability are limited to 100 db peaks.
Back in the day when we used to calibrate our systems we would set the volume control on our pre-amps to 12:00 on the dial and then advance the input volume controls on our power amps to a level just a tiny bit above our preferred listening level. This would allow for a greater range of adjustment on the volume control. It also calibrated the loudness control switch function and made fine adjustments at lower levels easier on the dial . But integrated amps and recievers took that capability alway from us.
Now as why to more power. Well there are many different answers to that. Smaller speakers require the woofers to move further to reach lower frequencies and means you need more power because the voice coil has to be longer and the magnet structure longer, too. Making the woofer less efficient, So smaller woofers and speakers maybe more practicle but they require more power. Some people don't like the sound of blaring horn speakers. The horn acts as an acoustic amplifier. Remove the horn and you need more power to reach the same levels as before. Some time more than 10 or 30 times more power. Speakers in sealed tight enclosures, the back wave is being used as a spring would be to make the cone movement more linear, but that back wave puts resistance to the cone and that makes the speaker even more in-efficient. So you might need 4 to 8 times more power again. Then their are paneled speakers using magnetic fields and thin
wires attached to large sheets of plastic to generate sound. They require 400 or more times the power of large horn loaded speakers.
If you go to a live Symphony concert and sit about 30 feet away from the conductor the peak sound levels run around 104 db . Now you can reach that level in your home with a very large Horn loaded speaker with less than 1 watt feeding each speaker. Average speakers today with a listening distance of 10 feet will require about 100 watts per channel to reach those authentic live performance levels. But most people only listen with average recording to 85 db. So thats much less or about 3 watts to each speaker. Aren't we fortunate. But if you listen to classical music that hasn't been over processed you might need 30 watts for each speaker for short instantaneous peaks. This is probably your situation. But if you listen further away each time you double the distance you need 4 times the power. I listen at 16 feet so I would need at least twice as much power as you do. My speakers our 5 to 6 db less efficient than yours so that means 4 time more power. So in my case I need 8 times the power you do, and because every once in a while I want to listen at full concert hall levels that means I need another 40 times more power than you do. So while you may never need more than 3 or 4 watts to keep you happy and you only listen to average recordings I might need 600 watts to each speaker in order to reach concert peak levels. But thats rarely the case. 30 watts per channel is all I really need 95% of the time. But I have over 700 watts a channel just in case I do want to listen at the levels of a live concert at 30 feet.
Now my fathers old friend and classmate Paul Klipsch made his measurements 3 or4 feet behind the conductor and there fore said for authentic sound reprodduction your system needs to be able to produce 114 db of sound level. Well thats requires 10 time the power of the 30 ft distance. So only a horn loaded speaker can produce those kind of levels with reasonable amounts of power. At 10 feet listening distance about 50 watts per speaker. Your speakers would require over 40 times that much power or 2000 watts and mine about 8,000 watts. Well thats not going to happen thank goodness. Then you ask why most musicians having hearing issues? Doesn't matter if they are classical, Jazz or Rock and roll musicians. Anything over 85 db for more than 4 hours and your hearing is going to suffer. Then every time you increase the levels above that the time of exposure drops significantly. Fortunate for us music has large changes in level from very soft to very loud in most cases. Its only been since the advent of sophisticated recording manipulations and the advent of rock and roll that the sound levels remain fairly constant for long period of time. Thats why Rock and Roll along with disco and its over emphasized highs can be danger to our ears.. Of course riding a motor cycle with straight pipes or using a table saw or shooting a shot gun with out hearing protection can instantly compromise your hearing for the rest of your life. Ever try to replicate the sound of a steam engine passing or a dragster going down the track with your sound system. First of all, it can't, so don't even try. Movie theaters with all their sound equipment capability are limited to 100 db peaks.
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I did not know that. You mean past 12:00 the volume knob is providing boost to the signal between the input and the preamp? More details, please! Thanks.
twiiii
Lunatic Member
The phono stage has 40 db more gain for MM cartridges and 60 db more gain for MC cartridges than the gain for line level inputs. Plus there is 15 to 20 db gain more available past the 12:00 position for quiet recordings, is usually the case. There might be slight variations on that practice. Of course pre-amps with a .7 volt out put rating or a 1.0 volt rating may not have as much total gain as the preamps designed to drive amps with 2.5 to 4 volt sensitivities. My pre-amps have always had a 10 volt capability. Its not necessary, but that way when your hear distortion at loud levels its almost always the amp. You don't want the scenario where your guessing if its the source or the pre-amp section or the amp. Its bad enough and dangerous to the speakers when the amp section is distorting but if the pre-amp or the source were distorting also it makes for an even more dangerous and destructive situation for the speakers and other stages of the electronics.
Every listener should do themselves a favor and bookmark this link:
1) Use it to determine the wattage needed at your listening position to go as loud as you'd ever want to go. Confirm that you likely already have more power than you'll use.
2) Use it again every time you fall into the audio hobbyist's trap of feeling the need for 'MO POWER', to reassure you that you indeed already have the power you need and can use those dollars saved for something useful.
Most listeners are usually using LESS THAN one watt at normal listening levels. Unless you have a very large room or are intent on destroying your hearing, the need for big wattage doesn't exist.
1) Use it to determine the wattage needed at your listening position to go as loud as you'd ever want to go. Confirm that you likely already have more power than you'll use.
2) Use it again every time you fall into the audio hobbyist's trap of feeling the need for 'MO POWER', to reassure you that you indeed already have the power you need and can use those dollars saved for something useful.
Most listeners are usually using LESS THAN one watt at normal listening levels. Unless you have a very large room or are intent on destroying your hearing, the need for big wattage doesn't exist.
It's too simplistic in that it doesn't consider power compression or lobing for multiple speakers.
For the vast majority if listeners it is entirely adequate and wildly useful. It accounts for multiple speakers.
Thud3
Active Member
My real life experience concerning watts,
back in the late 70s and early 80s:
I had a Marantz1150 with 75WRMS/channel powering JBL L100 speakers. I wanted more bass, so I bought a pair of JBL4430 speakers. The Marantz was unable to drive them without clipping, even to moderate volume. So I bought a Crown PS200 with 90WRMS/channel. Still not enough power, clipping, albeit at much higher volume.
So I bought a second Crown PS200.
Flipped the switches on the back of the Crowns, bridging them to MONO with 270WRMS each. One mono amp for each channel.
No more clipping, and as loud as I want with chest thumping bass.
FWIW.
back in the late 70s and early 80s:
I had a Marantz1150 with 75WRMS/channel powering JBL L100 speakers. I wanted more bass, so I bought a pair of JBL4430 speakers. The Marantz was unable to drive them without clipping, even to moderate volume. So I bought a Crown PS200 with 90WRMS/channel. Still not enough power, clipping, albeit at much higher volume.
So I bought a second Crown PS200.
Flipped the switches on the back of the Crowns, bridging them to MONO with 270WRMS each. One mono amp for each channel.
No more clipping, and as loud as I want with chest thumping bass.
FWIW.
www.firstwatt.com
www.firstwatt.com
I'd trade any of my 100wpc amps for a pass 25wpc.
My sta2080 has no problem driving a set of Mach 2 s and klh at the same time plenty of bass to loud levels ! Rated at 80wpc at .03 % . My 140wpc carver has a little more punch , but over the sta 2080 sounds better and I had. A Denon and an sta2290 later version both rated at 100 wpc that the sta2080 out performed in every way ! That being said my speakers rang from 90-93 db and are pretty efficient !