Why do some speakers sound better with more power?

[trudge1984]

I just restored a pair of KEF 104/2’s. I read a ton of posts and watched many videos on restoring them. One overarching theme in most of the posts was how good they sound with a lot of amps but they really shine with some power behind them. Why is that? I sort of understand the concept of efficient and inefficient speakers but this is not necessarily how loud the speakers will go with a powerful amp but how good they will sound at any volume correct?

At low volume does a powerful amp just have more “oompf” driving the speaker so it sounds better? What does better mean when referring to speakers that need a lot of power to sound good?

Any clarification or info on this would be much appreciated.

 

[joecoulson]

Search “headroom” as it relates to amplifiers

 

[spark1]

I just restored a pair of KEF 104/2’s. I read a ton of posts and watched many videos on restoring them. One overarching theme in most of the posts was how good they sound with a lot of amps but they really shine with some power behind them. Why is that? I sort of understand the concept of efficient and inefficient speakers but this is not necessarily how loud the speakers will go with a powerful amp but how good they will sound at any volume correct?

At low volume does a powerful amp just have more “oompf” driving the speaker so it sounds better? What does better mean when referring to speakers that need a lot of power to sound good?

Any clarification or info on this would be much appreciated.

In my view, the only thing it can possibly mean is that they need to be loud(er) to sound good.

Assuming an amp with enough power to avoid clipping distortion, any additional power that the amp is capable of producing is only potential power. It does not exist until the volume control knob is turned up, and therefore can have no effect until this occurs.

 

[g..v]

Fletcher- Munson curves are always in play. In order for the bass and treble to catch up with the mid-range, you need more power.

 

[BMWCCA]

Fletcher- Munson curves are always in play. In order for the bass and treble to catch up with the mid-range, you need more power.

Fletcher-Munson relates to volume (sound level), not power. The human ear has evolved to be more sensitive to mid-range sounds at low level while highs and lows are repressed. Must have something to do with hearing the lion in the jungle before he sees you, or something equally Darwinian. The bass and treble "catch up" as the sound level increase. I believe a more powerful amp is usually one with a higher damping factor which generally is thought to control the woofer better.

Even if I don't know the why, I have run enough experiments with similar but more-powerful amps on the same speakers at the same level and (not always low) and the L7 JBLs sounded better with a Crown PS400 than they did with the Crown PS200. They will sound just fine even when powered by a Crown D75A, but better with a more powerful amp. When I bought my first Crown the store gave me three to take home to try in my own system: D60, D150, and DC300. I tried to love the lower-powered one but hearing the others made me adjust my budget. In the end I chose the D150 as a compromise, and still have it today 50-years later.

 

[Nyjblbob]

Fletcher- Munson curves are always in play. In order for the bass and treble to catch up with the mid-range, you need more power.

I never heard of that one, But Big woofer JBL's are like that. Low volume Eh nothing special at all.
Crank it just a bit, Oh Yea
Also the more Robust the Power supply the better,
with tube amps the bigger the iron the better at lower levels

 

[trudge1984]

Fletcher-Munson relates to volume (sound level), not power. The human ear has evolved to be more sensitive to mid-range sounds at low level while highs and lows are repressed. Must have something to do with hearing the lion in the jungle before he sees you, or something equally Darwinian. The bass and treble "catch up" as the sound level increase. I believe a more powerful amp is usually one with a higher damping factor which generally is thought to control the woofer better.

Even if I don't know the why, I have run enough experiments with similar but more-powerful amps on the same speakers at the same level and (not always low) and the L7 JBLs sounded better with a Crown PS400 than they did with the Crown PS200. They will sound just fine even when powered by a Crown D75A, but better with a more powerful amp. When I bought my first Crown the store gave me three to take home to try in my own system: D60, D150, and DC300. I tried to love the lower-powered one but hearing the others made me adjust my budget. In the end I chose the D150 as a compromise, and still have it today 50-years later.

So even at lower volumes you notice/noticed the higher powered amps consistently sound better? My primary speakers until I got the KEF’s were JBL L-26’s and they sound good at lower volumes but definitely sound much better at louder volumes. I’m just wondering would they sound better at all volume levels with a more powerful amp.

 

[trudge1984]

Search “headroom” as it relates to amplifiers

I read a bit on headroom and I’m not really understanding how it relates to speakers sounding better with more powerful amps. Why would the same music played at the same volume with two different amps (one more powerful than the other) sound better with the higher headroom amp?

 

[dcmfan]

One place where I hear the benefits of more watts is transients - a drum strike, the pluck of a pick on a string - that sort of thing.

Normal volume takes very few watts, but a sudden, sharp transient can be many decibels above the average and for that brief moment the amp needs to produce a lot more power very quickly.

If I use one watt to listen at 80 db, a drum strike at 101 dB will require 128 watts. The extra watts let that drum strike play without distortion.

 

[spark1]

I read a bit on headroom and I’m not really understanding how it relates to speakers sounding better with more powerful amps. Why would the same music played at the same volume with two different amps (one more powerful than the other) sound better with the higher headroom amp?

It will if the lower powered amp is clipping the signal. I try to assure that I have at least 12dB of headroom above the highest sustained (average) volume at which I might listen so as to minimize clipping. 12dB takes 16 times the power.

So, for example, if it takes 4 watts to obtain desired loudness at your listening spot with your speakers, you would need an amp capable of 64 watts without clipping to maintain 12dB of headroom. Or 128 watts for 15dB of headroom.

On a related note, let's say that the speakers in the example above have a sensitivity of 86dB. Replacing them with speakers having a sensitivity of 92dB would drop the power requirement to 16 watts for 12dB of headroom and 32 watts for 15dB.

Crest factor of a good recording may well be at least 12dB....and is often even higher, especially with classical music and soundtracks.

 

[JB1962]

In general, higher power amplifiers likely have better components than lower power amplifiers, therefore lower distortion levels, better signal to noise ratios, etc... Without getting into how much power is too much, because that answer is that there is no such thing, you do want an amplifier that has sufficient power in reserve (headroom) to be able to control the speakers without 'bogging down'.

As you stated, some speakers just aren't very efficient, they need more power, current, (?) to function at the same dB as more efficient speakers. There comes a point where a low powered amplifier will not perform as well with inefficient speakers. A higher powered amplifier will also run cooler at a given dB level than a lower powered amplifier.

I have been in this conversation before and used to think that it was just a given that more power would sound better, end of story. However it does make sense that that only applies to a point, if you're not using it, it doesn't matter if it's available. That said, if you need it and it's not there, that's when sound begins to deteriorate and pushed too far, break

So whether you like low volume levels and benefit from higher quality builds, or like higher volume levels and benefit from the higher quality and sufficient power, a high powered amplifier isn't a bad thing to have. Now before anyone feels the need, I will add that there are plenty of very high quality amplifiers pushing less than 15-30 watts, with the right speakers that may well be all you'll need. Just depends on what you demand of your system. Open to criticism, that's how we learn

Edit: Also, I have never had a low power amplifier that had LED's, or any other means, to signal if the amplifier is clipping, not saying that they don't exist, just not familiar with any

 

[trudge1984]

One place where I hear the benefits of more watts is transients - a drum strike, the pluck of a pick on a string - that sort of thing.

Normal volume takes very few watts, but a sudden, sharp transient can be many decibels above the average and for that brief moment the amp needs to produce a lot more power very quickly.

If I use one watt to listen at 80 db, a drum strike at 101 dB will require 128 watts. The extra watts let that drum strike play without distortion.

That makes sense especially if the lower powered amp isn’t capable of those momentary spikes. Besides the transients do you feel that a higher powered amp improves the sound in other aspects of the music?

 

[spark1]

In general, higher power amplifiers likely have better components than lower power amplifiers, therefore lower distortion levels, better signal to noise ratios, etc... Without getting into how much power is too much, because that answer is that there is no such thing, you do want an amplifier that has sufficient power in reserve (headroom) to be able to control the speakers without 'bogging down'.

As you stated, some speakers just aren't very efficient, they need more power, current, (?) to function at the same dB as more efficient speakers. There comes a point where a low powered amplifier will not perform as well with inefficient speakers. A higher powered amplifier will also run cooler at a given dB level than a lower powered amplifier.

I have been in this conversation before and used to think that it was just a given that more power would sound better, end of story. However it does make sense that that only applies to a point, if you're not using it, it doesn't matter if it's available. That said, if you need it and it's not there, that's when sound begins to deteriorate and pushed too far, break

So whether you like low volume levels and benefit from higher quality builds, or like higher volume levels and benefit from the higher quality and sufficient power, a high powered amplifier isn't a bad thing to have. Now before anyone feels the need, I will add that there are plenty of very high quality amplifiers pushing less than 15-30 watts, with the right speakers that may well be all you'll need. Just depends on what you demand of your system. Open to criticism, that's how we learn

I don't think I would agree that higher power amps have better parts or specs. I have not noticed any positive correlation between build quality and power rating.

 

[dane79]

If you don't need the power, you don't need the power. I switched from a Kenwood basic m1 to an Acurus A250 for a while. Both amps handled bassy and dynamic material with ease. But it's going to depend on your speakers and room, and you might not know until you give it a try. Also at normal listening levels, many of us are using less than 5% of our amplifiers available power, I have a really hard time believing that merely adding more unused power will improve sound quality.

 

[JB1962]

I don't think I would agree that higher power amps have better parts or specs. I have not noticed any positive correlation between build quality and power rating.

Did you read the whole post? It was a general statement and I did add that there are plenty of lower powered amplifiers that are very high quality

 

[JB1962]

If you don't need the power, you don't need the power. I switched from a Kenwood basic m1 to an Acurus A250 for a while. Both amps handled bassy and dynamic material with ease. But it's going to depend on your speakers and room, and you might not know until you give it a try. Also at normal listening levels, many of us are using less than 5% of our amplifiers available power, I have a really hard time believing that merely adding more unused power will improve sound quality.

Yup, room size is also a big factor that needs to be addressed

 

[spark1]

Did you read the whole post? It was a general statement and I did add that there are plenty of lower powered amplifiers that are very high quality

Yes, I read it. I don't find it to be true as a general statement. I just don’t think one amp's power rating compared to another's provides much insight about their relative quality.

 

[JB1962]

Yes, I read it. I don't find it to be true as a general statement. I don’t think one amp's power rating compared to another's provides much insight about their relative quality.

Okay, I could be wrong about that. I do have a limited exposure to the vast sea of amplifiers available, I can only share from the experience that I have. There are many here with an incredible amount of experience, which is why I am here. Thank you for your input, I am not only open to criticism, I appreciate it. Thanks for expanding my experience!

 

[AudioGMan]

I say it’s a combination of the woofer’s suspension and it’s Qts and Fs parameter. Also the motor strength of the drivers and the manufacturing tolerances. All those factors are going to affect the efficiency. If a woofer has a stiff suspension it’s going to take more power to get it moving than a woofer with a loose suspension. Of course the enclosure is another factor.

 

[E-Stat]

A mentor of mine used the term “authority” to describe the ability for an amplifier to drive a speaker with wide dynamic content and continue to sound at ease.

I think some might be surprised how much power that can take for a wide range of speakers. While the New Advents in the garage system were designed to work with 30 watt amps, they can only take on that authority with 300. As others have mentioned, it’s about meeting peak demands without strain, not average levels.