Does bass really require more power?

[T3RIAD]

Look at pretty much any review where someone upgraded their amplifier, for speakers or headphones, and the number one first thing they will always say is, "there's more bass now."

Does such a universal concept have any technical basis? When you reach the power limit of an amplifier, is the bass the first thing to go?

I've always wondered if the saying that more power = more bass is just another one of those things that people hear because they've learned to expect it.

 

[PaulD]

Bass requires moving more air, a greater volume of air than higher frequencies. That requires more driver movement, which needs more energy (power) to achieve that.

If you already have adequate power for the volume you are playing, then more power will not add anything. However, power specifications are a bit "rubbery" - ill-defined might be a better description.

Look up "crest factor" to help you, here are a few links: (some better than others)
http://blog.powerandtest.com/blog/what-is-crest-factor-and-why-is-it-important
https://www.prosoundweb.com/understanding-the-nuances-of-crest-factor/
https://www.prosoundweb.com/tech-tip-of-the-day-the-crest-factor-in-mastering/
https://geoffthegreygeek.com/calculator-amp-speaker-spl/

Looking at these it's easy to see how you might want a couple of hundred watts of power to adequately drive your speakers to a reasonable level, and to leave some extra headroom.

 

[MZKM]

Since bass can have difficult impedance/phase, I’m assuming their previous amps simply didn’t provide enough power when listening at loud volumes.

4ohm loads require 2x the wattage compared to 8ohm (same relation between 2ohm & 4ohm), so an ideal amp has 2x the wattage, but many are around 1.8x, really poor ones are like 1.2x. So for amps that are far from doubling down, the areas of low impedance won’t get the same max wattage compared to amps that are close to doubling down and have the same rated 8ohm wattage.

Phase dictates how much power the amp draws in relative to how much it puts out (outside of efficiency). If the phase is 45°, the amp draws, to my knowledge, 2x the power from the outlet relative to if the phase was 0°.

 

[solderdude]

Look at pretty much any review where someone upgraded their amplifier, for speakers or headphones, and the number one first thing they will always say is, "there's more bass now."

Does such a universal concept have any technical basis? When you reach the power limit of an amplifier, is the bass the first thing to go?

I've always wondered if the saying that more power = more bass is just another one of those things that people hear because they've learned to expect it.

Below the spectrum of a well recorded song

As you can see most of the 'power' is in the lower frequencies.

To get the sound 2x as loud (+10dB) you need 10x more power. When you want to go yet another 2x louder you need 100x more power.
You see where this is going.
When you want to play loud with 'authority' you thus need lots of power.

Going from a 40W amp to a 60W amp won't help as it will only be 1.8dB louder which is as good as inconsequential.

The large voltage(power) excursions of the low frequencies will clip the amp. It is not that 'bass' goes first as the output signal of an amp is an addition of all signals. An amp can and does not discriminate between frequencies.
The smaller and higher frequency signals thus will also (temporarily) clip (be removed) when the amp clips.
This is audible as 'grungy' mids and coarser treble.

Having enough power to spare (headroom) thus makes sense. You can play louder with more power and the way our hearing works (equal loudness contours/Fletcher-Munson) this also means bass becomes relatively more audible.
So more power allows for more impressive sound/bass without it turning 'nasty'

When upgrading do this by buying an amp with 5x to 10x more power.

 

[dfuller]

Short answer: Yes.

Long answer: Bass requires more driver movement as well as larger (and therefore heavier) drivers, so the amp needs more power to produce it. Add to the fact that our ears are perhaps not the greatest for lower frequencies, and it starts to add up how much power you need at low frequencies.

There is a reason you sometimes see speakers biamped (or even triamped, depending on the design) - bass needs a whole lot more power than midrange or treble does so it makes sense to amplify it separately with more power than midrange or treble. Commonly with active speakers you'll see something like my Focal Shape 65s, which are 25w treble/80w bass.

 

[Head_Unit]

more power = more bass

No, and I don't think those comments are about at maximum volume. I believe they are about the character of the sound. I gifted a friend an Oknyo TX-8511 I scored for $30 as a Hannukah present. Swapped out his vintage Yamaha, VOILÁ the bass was noticeably I dunno warmer, more defined, more something. Not a HUGE difference no, but we both agreed it was "more." I believe this has to do with maybe the damping of the amp versus the speaker, possibly small variations in frequency response. And yeah somehow bigger power amps often seem "more" which is quite possibly due to internal topology reflecting into the sound.

But it's a crapshoot. Because then again, there's this result (and a similar I did once with a Crown Microtech versus a 135 lb Crest PA beast):
https://forums.stevehoffman.tv/threads/denon-vs-parts-express-round-1.984507/

 

[RayDunzl]

But it's a crapshoot. Because then again, there's this result (and a similar I did once with a Crown Microtech versus a 135 lb Crest PA beast):
https://audiosciencereview.com/forum/index.php?threads/does-bass-really-require-more-power.14828/

Nice Déjà vu link there...

 

[solderdude]

I gifted a friend an Oknyo TX-8511 I scored for $30 as a Hannukah present. Swapped out his vintage Yamaha, VOILÁ the bass was noticeably I dunno warmer, more defined, more something. Not a HUGE difference no, but we both agreed it was "more."

The 'problem' here is that the old Yamaha may have not worked 'correctly' or the tone control pots of the Onkyo may not have been in the electrical 'center position' while mechanically being there. It could well be that the Yamaha, for some reason had aged and was rolled off. Maybe some loudness was implemented in one of the amps. Without measuring both we cannot say and should not rely on 'impressions'.
It could be that the volume control position for the same loudness differed.
I don't think the Onkyo will have an unusually high output R, higher than the vintage Yamaha either, but it could for some reason.

The actual problem here is that the circumstances differ too much and neither of the gear had been checked for FR under load.
This means all perceived differences may or may not be of electrical origin and without taking actual tests it is merely an experience.
Of course, almost all amplifiers sound different experiences may come from other than electrical source.
Also, when swapping amps for other ones usually one 'tries' it out (listens loud) and comes to the conclusion that the more powerful amp is better sounding because it can go a few dB louder without distorting or the volpot position/feel differs or one expects an improvement (subconsciously).

 

[Head_Unit]

Nice Déjà vu link there...

oops...fixed it. It was weird, the link wouldn't attach normally, so some kind of glitch...

 

[Head_Unit]

Below the spectrum of a well recorded song

How did you take that? I've been looking to do a survey of that kind of thing; I'm looking for some app that could measure peak and RMS power in each band...

 

[solderdude]

Loaded a song into audacity, seleceted whole song, clicked 'spectrum analysis'.
When you look at a waveform (also in audacity for instance) and zoom in on a part of the waveform you will also see the largest signal is low frequencies and the higher the frequencies are the smaller the amplitude (with some peaks reaching higher)
The spectrum is very similar to that of pink noise.

When you have an analyzer that has pink noise as measurement signal and look at the spectrum of a well made recording you can also see that the distribution of bass and treble is about the same in amplitude. This too shows that music has most energy in the lows.

 

[abdo123]

Since bass can have difficult impedance/phase, I’m assuming their previous amps simply didn’t provide enough power when listening at loud volumes.

4ohm loads require 2x the wattage compared to 8ohm (same relation between 2ohm & 4ohm), so an ideal amp has 2x the wattage, but many are around 1.8x, really poor ones are like 1.2x. So for amps that are far from doubling down, the areas of low impedance won’t get the same max wattage compared to amps that are close to doubling down and have the same rated 8ohm wattage.

Phase dictates how much power the amp draws in relative to how much it puts out (outside of efficiency). If the phase is 45°, the amp draws, to my knowledge, 2x the power from the outlet relative to if the phase was 0°.

Doubling down is not important and is not indicative of a good or a bad amplifier.

You either have enough power (voltage and current) or you don’t, and that’s what matters. Signals are very complex with regard to impedance and most amplifiers should handle complex impedances including dips just fine.

 

[MZKM]

Doubling down is not important and is not indicative of a good or a bad amplifier.

You either have enough power (voltage and current) or you don’t, and that’s what matters. Signals are very complex with regard to impedance and most amplifiers should handle complex impedances including dips just fine.

If you are using your amp at its limits, then doubling down or close to it is important, especially for lower wattage amps. If it doesn’t, then your frequency response is changing and can be done to an audible degree.

If you have an amp that’s like 200W into 8ohm, then sure it doesn’t really matter if it gets to 400W into 4ohm as even 300W would be enough.

 

[ZolaIII]

Example (1972 no excess or sub bass and layerd [bass, instrumental and vocal] for easier understanding):

 

[dfuller]

no getting my solution.

I'm pretty sure you posted in the wrong place.

 

[Head_Unit]

Doubling down is not important and is not indicative of a good or a bad amplifier.

You either have enough power (voltage and current) or you don’t, and that’s what matters. Signals are very complex with regard to impedance and most amplifiers should handle complex impedances including dips just fine.

Having tested a bunch of stuff with The Power Cube, I have to disagree about the second point unless you mean under ordinary conditions). A lot of amps cannot handle nonresistive loads so well near their clipping point. Granted, over time we tested a lot more car stuff than home units, but then again those are just Class AB with switching power supplies in front.

As for the doubling, out of a couple hundred measured personally or by colleagues or Stereophile I've only ever seen I think 3 that truly doubled power at clipping. One was https://www.stereophile.com/content/ps-audio-stellar-m1200-monoblock-power-amplifier-measurements, another was I think a CH Precision $60k or so, and I forget the 3rd. There were also some car audio competition cheater amps but I don't count those and my recollection is they did not actually double power into their lowest rated impedances. Almost all the car amps would give like 50-60% more power at clipping into 2 ohms versus 4, and similar for home stuff.

Now, does that matter? Good question. It matters near clipping, and probably (?) into nonresistive loads. I'd expect more power into an "8 ohm" speaker at a low frequency with a tough phase angle from a 100W/200W measuring amp than one that measured 100W/160W. Then again as someone once posted, just get a huge amp and you're done, no worries. Still, I tend to believe that the big stiff power supply needed to truly double *might* impart a different sonic character. Insufficient data, never tested blind that I'm aware of. It would be interesting to get say Bruno Putzeys or PS Audio or Bob Carver etc etc to build both a "typical" amp and a "doubling" amp and do some listening tests. It would also be interesting to ask stellar designers what they think about the issue of doubling power...

 

[Doodski]

Still, I tend to believe that the big stiff power supply needed to truly double *might* impart a different sonic character.

I agree fully and completely. How could it not impart a different sound?, is what I think.

 

[restorer-john]

It could well be that the Yamaha, for some reason had aged and was rolled off. Maybe some loudness was implemented in one of the amps. Without measuring both we cannot say and should not rely on 'impressions'.

I've never measured a Yamaha anything that was ruler flat. Pretty much all their vintage classic amplifiers, receivers and preamplifiers have slight LF and HF roll-offs. They always sound "clean" but I've never heard a Yamaha that had a classic "warmth" to it.

Their so-called "natural sound" was/is a house sound IMO.

 

[Doodski]

I've never measured a Yamaha anything that was ruler flat. Pretty much all their vintage classic amplifiers, receivers and preamplifiers have slight LF and HF roll-offs. They always sound "clean" but I've never heard a Yamaha that had a classic "warmth" to it.

Their so-called "natural sound" was/is a house sound IMO.

Comparing vintage 80s and 90s Yamaha amps in the sound rooms I found they mostly sounded the same as a Luxman and HK. But there was a couple of HK models that had a little more bass in the lower end. The differences where so so subtle that I decided to push the Yamaha gear and with the savings get the customers into more expensive speakers. It was a no-brainer.

 

[abdo123]

near their clipping point.

Then like i said they ran out of either voltage or current. no 'special' sauce for doubling down.