Why do speakers improve with more powerful amps?


So, if I have a solid state amp that more than adequately powers a speaker, why do people recommend a larger more powerful amplifier to improve things?

Why do more powerful amplifiers impact speaker sound quality in a favorable way? Is it because more power is reaching the speakers? Mid and Tweeter drivers I was told receive a reduced signal versus bass drivers which receive relatively more power via crossovers.  All for the purpose of balancing a signal going to the various drivers.

 

 

jumia

I value quality over quantity in wattage for amps.  Blessed those who need 500 or 1000wpc, but for indoor listening, 10wpc is more than I'll ever need.

@emergingsoul 

Yeah, quite surprised myself! I have also driven them with great success using a single ended solid state VFet amp (Pass DIY) which is rated between 8 and 10 watts. 
 

For fun, I got one of the Fosi V3 amps. It, is rated at 300w into 4ohm. (Complete BS…) Hooked it up to the speakers, and it was turned up to 3 o’clock on the dial, at which point it was distorting and no where near as loud as the 30W at 10 on the dial. 
 

it’s a learning thing…

 

And thanks, the 7T is a wonderful, and surprisingly good sounding pre. Unfortunately, the right channel died, so now I have to pull it open and figure out which bit when bad…

@perkri 

Amazing answer very helpful. Impressive how you drive inefficient speakers with so little. Worthy of study.

That's a really pretty Marantz vintage piece.

 

Power supply

Power supply

Power supply

Bigger amps have bigger power supplies. The signal that gets sent to the speakers, is fed directly from the power supply. Bigger power supply, more dynamic headroom. 
 

My 30w class A amp, with a massive power supply - 192uF of capacitance and a 500va transformer, more than adequately drives my 80db 4ohm speakers. 
 

An amp needs a power supply that can handle the difficult passages in a piece of music. 
 

I agree w the comment above where an amp should work within its linear region. And to make a big power amp that is operating in an ideal manner at low power, takes some skill. Having two output transistors per channel vs 16 per channel has some benefits.
 

So many variables when it comes to having great synergy between amp/speakers.
 

There is a dynamic load being presented to a reactive source with an ever changing signal. 
 

Bigger isn’t necessarily better. Better, is better.  

@chowkwan wrote:

One man’s datapoint. Your mileage will vary.

VTL 500 (500 watt monoblock) powering tweeter on a Klipsch Jubilee and VTL 750 (750 watt monoblock) powering the bass on same Klipsch Jubilee. The Jubilee is designed for bi amping and comes with an active crossover. The Jubilee has a sensitivity of 105 db..

https://youtu.be/_7ZGLrOpCQo

https://youtu.be/xUMDlpVu98w

Then the Wotans arrived. Switched the VTL 750 to the tweeter and put the VTL Wotan (1250 watt monoblock) on the bass. It’s not just a bit better, it’s a quantum leap better. Just playing YouTube, man.

Is it headroom or damping factor or whatsoever? Couldn’t begin to tell you. It just sounds fabulous.

Don’t let beliefs stop you. Keep exploring.

Exactly - keep exploring. And with that in mind, have you tried the Wotans on the midrange/tweeter horns and the VLT 750 on the bass horns? Yes, I know - why the hell would one use the more powerful amp on the HF-section, with the higher sensitivity even? Remember, 750 vs. 1250 watts doesn’t even account for a 3dB difference, and 750W will still get you a mighty long way with the high eff. bass horns. If the Wotans are the better choice on the HF-section, perhaps in triode mode (with the VTL 750 on the bass horns, say, in tetrode mode), then that’s what it is. If found out myself that the more powerful amp on my 111dB sensitive MF/HF horns (>600Hz) was the better choice, though there was only a 50W difference (575 vs. 625W). Common wisdom would’ve dictated the less powerful amp to drive the HF driver, but with so much capacity at hand with 100-111dB sensitivity it really comes down to shuffling the pieces and see what works the best - irrespective of presumptions and numbers. The question of course remains if a further gain in headroom, even with those wattages and very high sensitivity ratings, has a hand in this, and that may bake the noodles around here if people dare to follow that line of thought with the (little) attention typically invested in headroom.

Interesting comments about the vtl Monster tube amplifiers above.

vtl website has an interesting few paragraphs about tubes that may be of interest 

https://www.vtl.com/technology/why-tubes/

 

One man’s datapoint. Your mileage will vary.

VTL 500 (500 watt monoblock) powering tweeter on a Klipsch Jubilee and VTL 750 (750 watt monoblock) powering the bass on same Klipsch Jubilee. The Jubilee is designed for bi amping and comes with an active crossover. The Jubilee has a sensitivity of 105 db..

https://youtu.be/_7ZGLrOpCQo

https://youtu.be/xUMDlpVu98w

Then the Wotans arrived. Switched the VTL 750 to the tweeter and put the VTL Wotan (1250 watt monoblock) on the bass. It’s not just a bit better, it’s a quantum leap better. Just playing YouTube, man.

Is it headroom or damping factor or whatsoever? Couldn’t begin to tell you. It just sounds fabulous.

Don’t let beliefs stop you. Keep exploring.

IF you take a lower powered Amp, say 10 watts, running at .5% distortion and run it at 5 watts what is your distortion level compared to a high powered Amp, say 100 Watts and run it at 5 watts output, with .5%. That is not .5% at 5 watts but IS .5% at the capacity of the amp, or at a designated % of output. With a higher wattage capacity you can run the distortion right down to the floor. That is just one of the factors to consider.

This, or one could look at it from a different perspective: say you have an active speaker setup with no passive crossovers and potential steep phase angles - that's one way to effectively make the same amplifier "more powerful"/adding headroom for a given SPL or certainly making more effective use of its capacity with an easier load, all the while making it sound closer to its performing envelope - i.e.: better. Part of that is also dividing the workload between that amp and others to handle their respective and limited frequency spans; in a 3-way setup the amp handling MF/HF is freed of LF which equals lower distortion and better sound. The amp handling upper bass to lower/central mids is freed of everything else = better sound. Sub/central bass amp handles only that = better sound. You could have a blasting crescendo in the lower registers and it wouldn't matter an iota to the amps handling the other registers. With a line level crossover preceding the amps and looking directly into their driver segments with no interfering passive XO's also leaves out any influence of a dividing network seeing the full output power of the amp. All of this effectively makes a given amp more powerful and better sounding for a given context vs. the scenario of it seeing into a passive, not least complex crossover, full-range at that. Active requires more amps (unless running a full-range driver per channel), yes, but this is just to show how the same amp benefits from a given set of circumstances (incl. higher speaker sensitivity and impedance) when it's usually anything but impervious to load. 

@fleschler

Awesome info above.
I saw your details, incredible wall paneling in your listening room.

Would be cool to see an updated system.

Among the finest sounding audio systems were those powered by medium powered Class A/B amps such as the classic McIntosh 225 and 240 (for mids alone-McIntosh MC30s).  Generally speaking, low efficiency coupled with low impedance speakers require high powered amps such as most planar speakers to achieve adequate dynamic range.  I had this problem when I owned stat speakers for 20 years.  I have permanently moved to dynamic speakers of medium to high efficiency, despite lower impedance and difficult phase angles because even my medium power amps have great current capabilities and overcome the impedance and phase angle difficulties.  70 Class A tube watts is plenty for my efficient but difficult load (6 12" woofers) speakers in my average size listening room.  35 Class A/B tube watts is plenty for my easier to drive Legacy Signature IIIs in my living room (I auditioned them with a measly 17 watt Sherwood 7100 receiver).  

Funny how whenever I hear Von Schweikert speakers at shows, they have extreme tube power amplification, often with $600K/4 power amps.  Maybe for the huge rooms they play in.  For the typical home listening setting, medium power is required.  As to field coil and other benign speaker power requirements, low power amps will sound best and huge power amps would be energy wasters and possibly blow up the speaker.  

Lots of overthinking on this subject but usually, common sense goes a long way. When I purchased my KEF R3 speakers, I had a conversation with a KEF engineer about suitable amps and he pointed me to a blog on their website about power requirements. At its most basic level, choose an amp that is 60 to 110% of the recommended power requirements if published by the speaker manufacturer. Ignore the minimum number because it is usually just enough to get the cones moving.

Narrowed down to those parameters, you can start looking at things like current delivery and such. In a perfect world, and amp just makes a tiny signal louder. What's left is what leads to all the arguments and discussions on forums. We all have to choose our own distortion preference and altered reality.

Having said all that, You can, and many people have filled books with what I don't know or understand about these subjects. 

 

Same amp brand, same board engineering, the bigger amp with the larger power supply and power reserves is going to sound better. That power is always there, at low or high volume.   Push your left finger (speaker) with your right finger (50w amp). Then push it with your right hand's palm (400w amp).   For one you almost always get a better damping factor and bass control. Think about it. and when the going get's tough it's even better.

But, different brands sound different, and quality varies. I recently moved from a 570w/1140w amp to a 160w/?s  watt smaller power amp (although with large supply and capacitance). The Odyssey amp bested my old W4S (decent sounding to me, before...) amp in five very audible ways almost immediately. Stunning. Power had nothing to do with it. The bass got way better too.   :-)

As for why buy low-efficiency speakers, I'll go with @Clearthinker's view on it (grin). Honestly, my ears have never heard a high-efficiency speaker that didn't seem 'in my face' to me,  but that's just my ears...  I'll just plod along with my 85dB Raidho D2s (room equalized flat to 30Hz and smile lots as they play.

@ricco275 

 

Yes, sometimes. But ultimately it is the whole system, and really important to have that power paired with the right speakers. 60db is fairly low… I typically listen at volumes I in the low 70’s. But I am using a 70 wpc tube amp. When I had a 350wpc solid state amp I listened about ten db or more higher. There are a lot of variables.

I wonder if what I often read is correct. That high current / high powered amps improve significantly the sound rendition at low listening volume like 60db.

I have a 2.5 watt Decware amp and a 300 watt Aavik amp class D....a 35 watt 845 SET amp and a Belles 70 watt integ amp.also a Peachtree GanFET 400 watt amp.....They ALL sound DIFFERENT But they  ALL sound Great !......To each his own....If one was BEST....No one else would sell any equipment......I love this Hobby!

"So why the hell do people buy inefficient speakers?"

Speaking only for myself, I buy speakers that:

A - fit the space I have for them; and

B - sound good to me

In my case (home office/desktop audio), the speakers that fit the space and sound best always turn out to be sealed/acoustic suspension 2-ways. As it happens, that type of speaker design really does tend to sound better with more powerful amps, mainly because so much power is required to move the woofers harder and harder w/increasing volume as the frequencies drop to neas the speaker’s resonant frequency (bass reflex designs operate more permissively near their limits).

But having said that, it’s probably not true that an amp twice as powerful as the one that can happily drive a given pair of sealed speakers, would necessarily sound better. More like the amp that can happily drive sealed speakers to fairly loud volumes has to be more powerful than one that would happily drive bass reflex speaker to fairly loud volumes.

Both higher wattage and lower wattage with respective lower and higher sensitivity speaker combinations each render unique sonic results. Just as both tube and solid state (or then combination thereof) extend that further.

Maybe a closer focus and discussion over quality power supplies and current delivery would be more relevant than this endless sensitivity argument.

@carlsbad2 

You listen to the first watt.  If it sucks, you don't need 299 more of them.”

this could have broad implications.  I’m going to file this in my “ life lessons “ folder.

thanks for the post.

Possibly if I make a comparison to mechanical engineering. A simple street car capable of 150 HP putting out 100 HP is going to be under far more stress and pushing harder on every last component in it than a muscle car capable of 500HP putting our 100HP. The muscle cars is barely idling and not under ANY stress.

@Phusis

This shows how easily it is to ignore the Facts of the subject and keep on trying to reinforce the idea that clipping is the ONLY place that headroom affects. Clipping is only a minor concern is is the LEAST of the actual AUDIPOPHILE reasons for having overhead.
Yes you can power a pair of headphones with a couple of well designed watts of power but you won’t be powering a set of Maggie’s with only that. You are mixing apples with oranges IF you think there is not a high level of sound quality in reference here. Or as I said before would you expect audiophiles totally ignore ALL of the statistics published about the Amps they are discussing or buying.
IF you take a lower powered Amp, say 10 watts, running at .5% distortion and run it at 5 watts what is your distortion level compared to a high powered Amp, say 100 Watts and run it at 5 watts output, with .5%. That is not .5% at 5 watts but IS .5% at the capacity of the amp, or at a designated % of output. With a higher wattage capacity you can run the distortion right down to the floor. That is just one of the factors to consider.

Not having to deal with the interaction between driver impedance and passive filter network gives the designer of an active crossover/equalizer much greater freedom and control to develop a superior product.

 

As some one who can do both, this statement is not always true. Depends. For certain, the digital/active domain makes time delay easy, which therefore makes high order, symmetric crossovers a lot easier to accomplish on a flat baffle speaker.

Try driving a set of Maggies with a 2W Decware Zen Triode. Not going to work. 

It’s about the ability of the amplifier to deliver transient response to whatever speaker they’re driving. Transient response can take loads of power momentarily. If your speakers are efficient enough to handle that from a low watt tube amp then great. I have found that most speakers require a lot of power to reproduce transients properly. Play London Grammar, “Hey Now” and tell me if your amp has enough power to handle it.

OP, Thank you for your kind words about my system. One of the greatest benefits after the doggies is the sound space three walls concrete (front and sides)… and large, highly asymmetrical space. Bought the house knowing there was a place for my system…. Had no idea it would sound so good. As they say, better to be lucky than good. 

@esarhaddon1 --

+1

@erik_squires wrote:

I recently asked a very similar question at DIYaudio and got some really in-depth responses which I felt really got to the root of the amplifier/speaker matching problem.

Take a look:

https://www.diyaudio.com/community/threads/if-speaker-impedance-wasnt-complete-what-are-we-missing.398934/

Good link/info, which further provided this:

I have a strong preference for line level active dividing networks ahead of the power amplifiers (Ref. 2, 12, 17). In this approach the power amplifier output is connected directly - except for a very low resistance speaker cable - to the voice coil of the driver. The amplifier takes maximum control over the motion of the speaker cone which gives a greater sense of clarity and dynamism compared to a passive dividing network between amplifier and driver. Active crossovers make much more effective use of amplifier power. A clipping woofer amplifier is not seen by the tweeter, which has its own amplifier. The clipping of the woofer amplifier may not even be noticed in this case. It would surely be heard with a passive crossover, where it might even overheat and damage the tweeter, because of the large amount of high frequency energy in the clipped signal.

Crossover filters for a speaker usually incorporate frequency response corrections for the individual drivers to obtain a desired overall response. The active network has the advantage of correcting easily for different sensitivities of drivers and equalizing not only the individual drivers but the combined response as well. Not having to deal with the interaction between driver impedance and passive filter network gives the designer of an active crossover/equalizer much greater freedom and control to develop a superior product.

@carlsbad2 wrote:

"headroom" is also a marketing term.

It absolutely is not, on the contrary it barely even registers as a factor in audiophilia - if it even could, pragmatically speaking. Tom Danley on headroom:

In audio, there is an expression headroom is your friend and I guess that is part of the message. What loudspeakers do wrong or non-linearly changes with level and the amount of misbehavior increases more rapidly than the level of the desired signal as you increase the operating level.

Well before a speaker burns out, it is severely compromised in it's performance.

With the heating of the voice coil, one finds the SPL decreases relative to the expected level with increasing power, also the systems tuning / frequency response changes at the same time, for the same reason.

For modern drivers, this power compression begins about 1/8 of the drivers rated power, if rated using the AES procedure.

Honestly there is so much BS regarding specs and such in commercial sound that to add a sense of realism or something to that mess, we have a 3rd party laboratory specify usable rated power. Hifi, don't get me started.

Great sound can be had with low and high wattage amps. Variables in implementation with speaking coupling, sensitivity, type of configuration, personal taste and requirements, individual benchmarks, etc. makes it come together for one or the other. 

What  my tiny little mind his learned from all this herein is that amplifiers are really really important to sound quality.

The comment above from @yxcbandit about more amperage improving control over drivers, if true, and I believe it probably is, is very insightful. With more powerful quality amps, it follows that drivers are better controlled.

I also believe that frequency response is vastly improved because of a more powerful amps ability to deliver a greater ability to achieve this.

Also with all the complexities of the crossovers going on behind the speaker drivers, and the inherent voltage balancing going on between all the drivers, the spread of power to all the various drivers is likely enhanced with improved power capabilities. Crossover design Controls more than just frequency range distribution and is a topic that is not well focused on or understoodon in my view. Individual drivers within a speaker don’t all receive the same level of voltage otherwise things would not be in balance. I think this may greatly influence how amplifiers as well as crossover design may impact speaker performance.

My 150 watt Herron M2 monoblocks sound better than 300 watt Ampzilla 2000 2nd edition monoblocks or PS Audio 350 watt M700 monoblocks with medium efficiency speakers. 

My 25 watt Quicksilver Horn monoblocks however sound better than the Herron amps with my Klipsch Chorus speakers.

Watts aren't everything. 

@hilde45 Great points!  I appreciate that.  Had not thought about that side of the topic.I'm pretty much a 'noob' with regards to the technical side of this.  Have learned a lot from this forum though over the last couple years.  I read a lot but don't post much.  Thanks!

It’s apparent when one reads threads like this that everyone has an opinion but only some have science and facts to actually backup their opinions.

That’s just the way it is but my only suggestion would be everyone is always best served by at least valuing the science and principles that account for how things actually work and doing the best they can to apply common learnings in their case as best they can. That’s the happy path to success. Anything otherwise is a detour at best and a dead end road in the worst case.

+2 @akg_ca

Roger from Rogers High Fidelity had an interesting comment somewhere about amps operating in their "sweet spot" of sort of a median power delivery, and noted as an example that very powerful amps into efficient speakers don’t get the amp into its best tone zone. Not his exact words but I get it.

@wolf_garcia I get it as well. I recently upgraded my tube integrated to a much more powerful Rogers EHF-200 MKII to power my Harbeth’s - what an idiot I am for buying such inefficient speakers:)

I now have the luxury of virtually unlimited headroom (yes, that marketing term again) and it definitely hits its sweet spot - but that is no where near its max rated output.

@mapman Wrote:

In any case it’s always better to have more power than needed than less. That’s called headroom and is a real engineering concept and not just marketing. You can look it up!

I agree! See articles Below:

Mike

https://www.cieri.net/Documenti/JBL/Technical%20Notes/JBL%20Technical%20Note%20-%20Danger,%20Low%20Power.pdf

http://diyaudioprojects.com/Technical/Papers/Damping-Damping-Factor-and-Damn-Nonsense-Floyd-Toole.pdf

@mlsstl 

Attempting to impress others or change their minds results in meaningless debate and frustration, both a waste of your time.

This should be emblazoned at the top of every thread!

 

@sejodiren

I’ve had a couple folks tell me in the 10’s Dahlquist group TELL me I need 200 wpc and my amp will never drive them to their capability. MY ears know what I’m hearing. How would they know?

Here’s what they might know: they tried powering the speakers at 200 wpc level and it improved things for them.

This happened to me -- I had what I thought was a good level of power for my speakers. They sounded good to me.

Someone else said they would sound better with more power. I asked why?

They said, "Because I tried what you have and it sounded good to me, but when I tried it with more power, it sounded better in a way I could not have imagined."

This is why others’ experience is valuable. Because the metric of "good for me" may be limited, and others who have experienced more can help shine a light.

It’s not about them telling me "what I should hear."

It’s about them telling me that "there may be more to explore."

And that’s how they would know about your speakers.

So some people here would like for you to believe that Signal to noise ratio, Load on the power supply, ‘Q’ of an amplifier and probably a dozen other Electronic FACTs about amps has nothing to do with how they perform. Yes we have plenty of people here that make unsupported outlandish statement trying to make themselves s look like they actually know something about Sound reproduction. Talking about arbitrary factors that in them self have nothing to do with the argument. Try understanding what ‘HEADROOM’ is before opening your pie hole. And don’t be offended, I left out the juicy comments, but needless to say these types would have you believe that ALL of the specs published on your equipment is useless information.

I don't believe damping factor has been mentioned. Higher power amps tend to have a higher damping factor. With bass in particular, a higher damping factor provides better control of the driver and depending on the impedance of the speaker can result in more accurate reproduction.

@carlsbad2 +1

I have a 450wpc amp that is outperformed by lower wattage amps. Many things are more important than power. This realization has me on the waiting list for a SET amp from Decware and I cannot wait!

@hilde45  I agree.  I've had a couple folks tell me in the 10's Dahlquist group TELL me I need 200 wpc and my amp will never drive them to their capability.  MY ears know what I'm hearing. How would they know? LoL  And being musicians ears that have listened to music since I was 13, I trust them.  I'm 68......

While it is fun to talk about our hobby, there are tons of opinions out there but it is up to each individual to decide what works for them.

No one would deny that "each individual to decide what works for them."

The point of these discussions is to understand some of the scientific principles so that individuals spend less time looking for needles in haystacks. Thus, it’s not just frivolity ("fun"), it’s about community inquiry and fact finding, where possible.

The conflation of inquiries into facts with some kind of abnegation of "individual decision making" is sort of dystopian; why would anyone suspect that?

Through the years I've went from 80 watts, to 140, to 200, to 300 and now at 600 and 1000 Amps. (Legacy IV 2 and IV 5 Amps). At normal listening, like a movie at slightly spirited volumes there is a difference, although slight. TURN it up, like listening to a Video Concert, and there is no comparison. One sounds like a recording, and one sounds like your THERE! 

@jumia   Why buy low efficiency speakers?

 

Because like everything else in life, it's a tradeoff.  It is easier to build drivers with high sound quality if they are inefficient.  It's against engineering principles as well as natural logic to have the best SQ and the best efficiency in the same design.  Think about it - if it were possible, everyone would be doing it.

The efficiency of the speaker and how the amp reacts to the load. It's as simple as the amp asking the speaker to move, or telling it to move. We talk about watts as if they are all the same. !00 volts at 1 amp is 100 watts, but 25 volts at 4 amps is also 100 watts. P = I X E. The more amperage an amp can put out the more control it has over a driver, specially large drivers with heavy cones.

I agree with the posters who indicate "it depends". My current Revel speakers are rated at 6 ohms with 87db sensitivity. They were initially being driven with a 50 WPC Arcam and I needed to push the amp pretty hard to get the speakers to sound their best. I switched to an 80 WPC Cambridge Audio amp and the speakers came alive. I noticed it especially in the lower frequencies. But there was also the matter of synergy. The CA amp, being a little more forward sounding, meshed better with the laid back sound of the Revels.

I had been using the Arcam with a pair of Paradigms that were rated at 92db at 8 ohms. That was another great synergy system. 50 watts was more than enough to make those sound great. 

It depends.

It's the old DQ 10's analogy I hear in the DQ 10 group I read info in.  "You need a minimum of 200wpc 'to make them sing' " Garbage.....  Mine sound fabulous with a 40 wpc Proton D540. Sister company to the early NAD company. But it's capable of 160 wpc for music transients when called for.  That's at 8 ohms. It's all about the current it was explained to me. I don't listen loud....so no need for a heat producing beast.

Roger from Rogers High Fidelity had an interesting comment somewhere about amps operating in their "sweet spot" of sort of a median power delivery, and noted as an example that very powerful amps into efficient speakers don't get the amp into its best tone zone. Not his exact words but I get it.

Why do more powerful amplifiers impact speaker sound quality in a favorable way? 

There isn't an equation written that can explain why, my experience is the soundstage gets more like it was in the studio when you add "enough" power. Once you get to "enough" you can park it there and more power than "enough" is basically a waste.

Why do speakers improve with more powerful amps?

They don't. It's a common misconception that fails the common sense test. If that were the case, a Decware Zen Triode, at a whopping 2 wps, would sound lousy. 

It's baffling why so many people believe such ridiculous things. 

@riie MC611 is a lesser quality amp than amp than the 1.25 - compare the MC611 to a Boulder 300 watt amp and I think you’d be surprised on the sound. 

Let’s take a look. You have an MC611 and a 1.25. Their sound signature is quite similar but the dynamics, bass and everything else imaginable to your ears is galaxies better with the 1.25. While I don’t know the technical reasons why, I know for a fact it is incomparable better. So in this case, the one watt story and why you would need another 1199 of them more makes perfect sense.