This is the best explanation I've seen on the whole internet

I've asked this question so many times and this is so far the best answer I've heard. The analogy of driving up a hill and having enough power to not loose speed makes perfect sense and in this case is easier to relate to than the hose/pipe analogy.

A power engineering analogy I like is voltage is the speed electricity goes through your body. Amperage is the size of the hole it leaves behind!

Wow, this was one of the coolest, most interesting and helpful descriptions on how driving speakers with an amp works. Asweome job. Thank you Paul!

The bit about the car going uphill is pretty much spot on

The “pipe flow” analogy is also useful. The pressure in the pipe equates to the voltage and volumetric flow rate through the pipe equates to the current. Two pipe flow scenarios of different pipe diameters can be delivering the same pressure (voltage) but the larger pipe diameter must have a higher flow rate (current)

Fantastic Paul ! I could listen to him all day long. I used to learn electronics as my first studies and job at Philips Consumer Communication. If Paul had been the teacher …. ❤❤❤

"sorry that was too long" ARE YOU KIDDING PAUL? Please, go on 😍

Thanks for the clear, detailed description of the way amplifiers drive speakers Paul

By far the best 'Q & A' format video you've done in a long time.

Excellent description of how amps work ! 👍🏽

The most common way engineers get double the watts into 4 ohms from 8 ohms is to send the spec sheet to the marketing dept.

Great explanation. It helps laypeople understand the basic relationship. The electrical engineers may debate some of the details, but this is really helpful to lay enthusiasts.

Thank you!A fantastic and engaging lesson that cleared things right up for me!

I really appreciate that you don't talk down to your audience. Thank you!

Usually very good but not really this time. Not fundamentally wrong as you need voltage to drive current (Ohms law), but it is the change in current flowing through a speaker coil that creates a magnetic field that causes the magnet attached to the cone to move, creating sound. Voltage without the ability to supply enough current quickly enough is pointless. You could generate high voltages in a preamp (tube amps do) but they wouldn’t drive enough current so you need a current amplifier stage (power amp) to move a speaker.

There's a million ways to explain something and most people, (apparently all engineers) think there way is best. I appreciate your humble layman's attempt, despite all of "geniuses" letting you know how wrong or incomplete you were.

The typical analogy is water and a water tank on a hill. Voltage is pressure, how much water is in the tank and how high the tank is above ground. Current is how much water flows when it is released from the tank. Load resistance (impedance) is the diameter of the hose connected. But add to this, internal PS resistance is the size of the opening in the tank regardless of the hose size. A little water not very high up? Not much power available. More water in a bigger tank up higher? More power available when needed. But until water flows out, it is only pressure/ voltage. Punch a hole in the bottom of the tank and add a hose. How much water flows how quickly is determined by the size of the hole and the size of the hose. The larger the hole or hose, the more (current) flow, but the faster the water empties out of the tank! Put on a wide hose (low resistance load) and lots of water can flow out if the hole is as big. But no matter how much water pressure is in the tank and how wide the hose is, if the hole is small (high internal PS resistance), only a trickle will come out relative to that hole size. But if the hose is smaller, the same size as the hole, it doesn't matter. So you need more pressure(voltage) to provide more water flow. But the flow (current) that results depends on the size of both the hose and the hole. So even if you have lots of voltage, but a high internal PS resistance (measured in Damping Factor), the voltage will be used up by both the load and way too much used up in the PS never leaving the amp. This can be seen in comparing the 8 ohm power to the 4 ohm because more voltage gets dropped in the PS as the load gets closer to the PS resistance. Or if the hole size is close to the hose size instead of wide open.

Thanks for the knowledge you have helped me with this struggle to explain why you might need a separate power amplifier.

Really appreciate you knowledge and your making it available to us. Thanks much.

This is the sort of thing that should be taught in elementary schools, and anyone who couldn't explain it at least as well as Paul does in this video would not get past fourth grade.

you really helped me to understand the operation of the amp, thank you

Thanks Paul. You are the best.

Brilliant very well explained Paul

I feel this was a pretty fair attempt at clarifying a rather complex and highly individualized set of variables - impedances, frequency, initial voltage, available current, topology, output device characteristics, dynamics, source material... it all has an effect on the final outcome. Not to the mention the deep relationship you touched on between voltage and current when fed into a load. One.thing that might have helped is the standard formula for calculating the power output of an amplifier: (V(RMS)^2) / Imp = Watts This, for anyone who has any acumen in mathematics, can be reworked to find the minimum voltage needed to get the required wattage. From there you can checking power section to see if it cab deliver.

Thank you Paul. Finally I get it!

This was enlightening!

Thanks for that explanation!

A great, simplified approximation to suite 99% of the people. Well done. Now after reading comments from all of the amplifier experts, let me ask all of you "how do bridged amplifiers work?" Since both bridged channels work on the same power supply the max voltage doesn't change. How does this go for those fixated on voltage? Why does the max watts increase? Where is the impedance relationship to watts, voltage and current? Where is the saturation of the power transformer come in to watts, voltage and current? Where is the power and current stage switch device power dissipation come in to watts, voltage and current? Is there such a thing as a minimum load and why? Feel free to way in with free explanations. I look forward to reading more.

Thanks Paul!

Good idea. Some audio experts know nothing about electronics, or electrical engineering. I am sure that would help them. This guy named Tesla knew a lot also.

You made it simple ✌️

Your good Paul Bravo

This was great... Thankyou

Very informative........👍👌

The "water tank & pipe" analogy is a useful and pertinent example to help understanding the voltage/current/impedance relationship. Suppose the loudness of a pair of speakers is fixed and this implies that the required voltage needs to be maintained to a certain level. Since the LS's impedance varies during its playing, the diffrent amount of current must be drawn from the amplifier to sustain the voltage. This explains why the amplifier needs to provide double the power when LS's impedance drops from 8 ohm to 4 ohm. I got really confused when it comes to the Mcintosh amps with Autoformers. These Amps are to provide consistant power whatever the LS's impedance is, and this function seems to be contradictory to the doubling-down requirement. Anyone can please share some knowledge here? Thanks.

That was excellent

As a matter of fact, AC/DC taught us that it isn't high wattage but high voltage rock 'n' roll.

My AMP is rated for up to 300W across both channels. It has a 36V 6A power supply connected to it so 216Watt total or 108W per channel. Now my speaker accepts max 60W. There system has no preamp: PC > DAC > AMP > Speaker. But the AMP has a VOLUME KNOB, if I lower the AMP volume will it lower the W going out to my speaker? Will this affect the voltage as well? And would it be better to downgrade the power supply to 24V 5A so it caps at 120W or 60W per channel? Will that harm the AMP which is rated at up to 300W (for both channels). Thank you!

Great explanation and it is simple until we start putting crossovers in and the impedance gets complicated.

Wow! You did a gr8 job IMO explaining a very tuff subject! There is a lot going on between an amp and the speaker. A power amp sees a conventional loudspeaker as a super fast variable resister. The resistance changes as the frequencies change, hence impedance. Am I right? All things the same, A speaker with a rated impedance of 1Ω could get a away with a lower voltage, but needs huge current to play as loud as a 16Ω speaker, which needs more voltage, but less current (kinda how WATTS come into play)! The amp's power supply rail voltage(s) has some influence on the amps output power. So, why is it that many modern car amps brag about being 1Ω stable, but average home amps shy away from anything under 4Ω? Kinda confusing to me. Thanks!

Hi Paul, thanks for your enlightening lecture. One question: Why do some tube amps have separate binding posts for 8 and 4 ohm speakers ? If I have a pair of 6 ohm speakers which binding posts should I use ?

As I look at any amplifiers specs where do I find the rating for the current?

If im understanding this correctly a country that has 240 v power supply will have more current coming out of an amp or is the voltage coming out the amp

paul I test preamps with a 4 ohm speaker resting on my shoulder and ear... haha.. i honestly start at the front and listen to signal as i go through the audio path.. i give you..i have it low volume...any preamp can easily play 4 ohm speaker anywhere in the path..

is it equally good if an amplifier solid state or tube gives the same watts in 8 as in 4 ohm?

I hate short videos....can't learn anything.......thats why teaching videos are long....great job teach....thks

what abt those Psb image bookshelf ?

Thanks.

No, no and no! It is not the voltage and it is not the power! It is the current! Which is known since Ørsted, and that was more than 200 years ago. That's why it is called an electrodynamic driver (moving charge = current). That's why the force factor is in Newton per Ampere. That's why long cables (extra series resistance) and heated voice coils (extra voice coil resistance) lower the output (if it was the voltage a heated voice coil would raise the output). And SPL is not a power quantity, so it is not the power. I think these kind of questions should be answered by Chris...

In the engine analogy RPM is voltage and amperage is tourqe, wattage is horsepower

@4:38 "Amps * volts = watts" Is there an ideal ratio (or balance) for amps and volts? In other words, would 2 amps * 20 volts yield the same results as 20 amps * 2 volts? Or to put it another way: -- For every amp, how many volts would you want? or -- For every volt, how many amps would you want?

How to know my speaker's wattage and voltage? It don't have a manual and sticker behind it. All I know it is 12 ohms.

I have the same issue, understanding this? My Amps - Lavardin MAP'S (mono), put',s out 56W pr unit, and still they handle almost every hunger Wattes speakers out there, incl. electric static. How come? ✌️❤️🇩🇰

Hi Paul... if power is dependent on voltage, why is the Sprout 100 power output the same in the US as it is in the UK where the mains AC supply is more than double the US standard ? Surely to compensate for the lower voltage at 110Vac you're not consuming double the current (20Amps ?) from the mains socket ?? 20Amps is a LOT to draw through a power cable. I realise the answer will be related to the transformer, but WHY couldn't amplifiers in the UK generate double the power output ?

Why does a 5.1 channel 150W (per channel) only have 325W power in? (I understand that the rating applies to Front, but there is still 3 other speakers, even if those are at idle).

Voltage (potential difference) across a load causes current to flow in the load - (speaker) - the resulting combination of voltage / current / resistance = power in watts. To calculate the RMS power into your speaker, you take the peak to peak voltage, halve it, (because the negative and positive half cycles are equivalent) multiply it by 0.707 to convert peak voltage into RMS voltage, and then square it and divide by your speaker impedance. For example 60V peak voltage across 8R speaker: 60V x 0.707 = 42.42V (RMS volts) squared = 1799.45V divided by 8 Ohms = 224.93Watts RMS into 8R. The peak current will be 60V divided by 8R = 7.5Amps (this will be the peak current at the top of the + half cycle and also - half cycle) - so the amp must be able to provide the 60V peak to peak voltage at 7.5 amps peak current in order to deliver the 224W RMS

Power is the time rate at which energy is produced or consumed. One Watt power is one joule energy per second. Electrical energy from the amplifier is transformed into motion of the speaker (kinetic energy) and heat energy in the speaker. The motion of the speaker produces sound waves in air. Voltage is electromotive force. Voltage is the amount of energy per electric charge. One Volt is one joule energy per coulomb electric charge. Current is the time rate of flow of electric charge. One Ampere or Amp is one coulomb electric charge per second. In simplest terms, the power in Watts equals the voltage in Volts times the current in Amps. Joules energy per second equals joules energy per coulomb electric charge times coulombs electric charge per second. An amplifier is a voltage source with voltage and current limits. The amplifier voltage output is independent of the load impedance within the voltage and current limits. The load impedance determines the current and power output within current and voltage limits. An amplifier provides voltage gain. The amplifier increases the voltage output of the preamplifier to drive the speaker. The amplifier must provide enough current to drive the impedance of the speaker. When the amplifier voltage or current reaches the limit, the voltage amplitude no longer increases. The audio signal waveform is distorted when input signals and amplifier gain push the amplifier to produce voltage or current greater than voltage or current limits. The voltage in Volts equals the current in Amps times the resistance in Ohms. This is Ohm’s Law. The symbol for Ohms resistance is Greek letter Omega Ω. Speaker impedance is complex. Resistance is a scalar. Impedance is a vector with magnitude and phase. Speaker impedance changes with frequency. Speaker nominal impedance is a simplification that allows us to approximate complex speaker impedance as resistance. The symbol for Ohms impedance is also Greek letter Omega Ω. Music signal voltage waveforms are complex. Music waveforms are made up of many fundamental frequencies and harmonics that start and stop and increase or decrease amplitude and frequency over time. Root Mean Square is a mathematical way of calculating the effective average voltage of a continuous periodic alternating waveform. RMS is different for different waveforms. For sine waves V RMS equals V peak times 1/√2 or about 0.7071. For sine waves V RMS equals V peak -3.01dB where dB = 20 log 1/√2. For square waves V RMS equals V peak. For square waves V RMS equals V peak -0dB. For triangle or sawtooth waves V RMS equals V peak times 1/√3 or about 0.5774. For triangle or sawtooth waves V RMS equals V peak -4.77dB where dB = 20 log 1/√3. For complex music signals V average equals about V peak -20dB or V peak times 0.1. Amplifier power is rated driving 8Ω resistors with sine waves. Amplifier rated power is a simplification.

Thank you !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Hi paul Love your videos. From Philippines

good video so guess if not got enough amps it's going to run low on volts to keep up and run out.

transistor base current times beta = collector current

So how does the uneducated figure out how much voltage an amp puts out when all that is advertised is watts? Interesting video, and many thanks for the time spent on it, but how does a consumer know how manufacturer is coming up with numbers (in watts!)

Why does impedance on the speaker go up and down?

How about, for instance, 20 volts at 10 amps or 25 volts at 8 amps? Both are 200 watts?

01:29 "More voltage more sound, it's as simple as that. End of story" - not a very good (or accurate) way to describe how an _electrodynamic_ speaker works. I get that Paul is looking for ways to answer questions with using a few technical definitions as possible, but here is a case where trying to answer a question may make things worse. At the end of the video Paul mentions that power is the product of current and voltage. Might as well _start_ with that. Explaining the physics of how an amplifier+speaker system works probably can't be squeezed into a 7 minute video, in which case perhaps it's best just to give directions (such as, shop for amplifiers with power ratings more than the minimum recommended by your speaker manufacturer.)

'Ole Audiophile here, it's a difference in basic audio philosophy at the start of the build. I am a biased individual toward multichannel, not stereo. This puts me at general odds with the entire purist movement, that would be great odds except the fix is in. I build from an HTR instead of a stereo preamp. Those of us that head down this path tend to use far more than one single stereo amp. From here, it may seem crazy to the un-initiated. That should get some comments...

It would be similar to RPM's and torque. You need more torque to go up the hill.

The formulas are simple. But what does physically happen? That's very hard to grasp. I mean the flow of electrons etc.

The real problem is everyone who isn't educated on the matter tries the reductionist approach: Gimme one thing that trumps all other properties. You can't really talk about electricity that way, you can't really talk about one without the other. Electricity also has magnetic properties that will affect it's interaction with electronic components.

Howdy. May I be a smartxxx ? Voltage and Amperege are not two independent things. Voltage drives amperege. And amperege drives the speakers. The PA must have enough amperege in stock, for the voltage to push through the speaker. Regards.

power = volts x amps / volts AC (rms) squared /speaker impedance =watts

Think of it as e=mc2. Where e=Watts, m=Volts and c=Amps. - Simples!

The problem is that amplifier manufacturer says it got for example 20 Watt. As a consumer we will never know if amp A is getting 20 Watts with 10 volts * 2 Amps.. Or amp B also 20 Watts but with ~6.7 volts * 3 Amps. But we CONSUMERS never get that info. Therefore it is pointless to say get one amplifier that has a lot of current (amps).. That is hidden and we will never know and makes the advice useless: "Get a amplifier with high current OR those speakers need high current" Yes you can go with higher wattage and hope that the current is larger than the one with lower wattage. When the lower wattage can have higher current but lower voltage so it will produce lower wattage.. But we will never know. If not somebody says that a amplifier always has the RATIO X between voltage and current. And what is the RATIO for consider a amplifier a CURRENT driving amplifier as the opposite to the far more common voltage driven amplifiers.. (That Avantgarde has for example.) Paul must understand that he is teaching the simple stuff and we all understand that by now. But the interesting stuff is as mentioned above. So focus on that and move on.

ELECTRONICS 101.

another conceptualization, borrowed from AvE: "Yer elechicken will tell ya it's just the Angry Pixies what come orta ta wall socket that'll get that ol skookum amp ta chooch them speakers right proper."

Countermeasures are only effective when the assumptions are true. If you lower the output impedance, because you think that an electrodynamic speaker is driven by voltage while it is driven by current, it is not only not effective, it is actually counter effective. Then, you make things worse! If you have a very low output impedance (a high damping factor) the performance of the speaker (and the crossover!) is very sensitive to temperature of the voice coil, different types of cables and modulation of the voice coil inductance, and electric damping that is all over the place. Whatever the damping factor of your amplifier is, when the temperature of the voice coil is raised with 10ºC (by playing some music) the damping factor is already only 25, at 50ºC only 5 and at the maximum power rating (party levels) around 1! Imaging what this does to the frequency response. And besides that, at maximum power rating the voice coil resistance is about doubled which changes the crossover frequency of the crossover filters with an octave! And, the better the driver, the more temperature and power it can handle, the more it changes the voice coil resistance (at the maximum power rating).

I struggle with Paul's statement "it's the Voltage! Trust me". Of course I trust Paul, but magnetic fields around conductors are created by current (=amps), not electric potential (=volts). Probably I would need to think it through properly form A to Z to understand Paul's advice he's giving, must have to do with the way typical electromagnetic dynamic speakers work.

Study Ohms law and it will be all clear.

Humans eat food to get energy to run our bodies. Power is energy per time. While you are watching this comment, you will use around 100 Joules of energy per second, which is equal to 100 Watts. Yes, your body is running a power consumption of around 100 Watts right now. When you run you use perhaps 400 Watts or even more. Likewise, speakers need power (energy per time) input to move their cones and playing louder needs more power. The reason voltage is what Paul considers most important is that speakers are normally tuned to be driven against voltage representing the sound amplitude. However, some people are of the opinion that speakers should be driven by current being a representation of level as this can reduce voice coil thermal coefficient issues and other artifacts. No matter which method, ultimately, as your body, with no energy (or power) no motion. You can only run as long as you have energy available in your body to consume. It's like an electric car. What accelerates it is power and not the battery voltage.

V = IR

At times, it is now possible for me to perceive the Earth and other planets eating themselves (reforming) from the inside out, due to the high intensity of charge that keeps us ..stuck to her dress, with charge gradient. Pressure and heat, are energy by proxy of materials, a hot planetary core responsible for the emission of charge gradient that anchors the Moon as well as the inhabitants of Earth. For me there is one major question to answer, Watts to weight. What are the energy costs of charge gradient interactions for differing materials, in Watts rather than Joules that pertain to Maxwell's thermodynamics, energy by proxy of materials). Refusing to fall for gravity, where charge attracts.

F=BIL

This can be explained much easier way. Power depends on current and voltage: P = I * V But current also depends on voltage (not only but still): I = V / R So after all P = V^2 / R As long as R (resistance) is constant (well it can be different for different frequencies but for certain frequency it is constant) it is the V (voltage) that makes a difference on overall power (P). So if your amp is good enough that it can provide necessary voltage for any frequency (i.e. any impedance that your speaker factually has) you will have good power level no matter what. PS. Impedance is not 1:1 to resistance, but for this explanation we can count this as the same

What happened to that Jennifer chick ?

It's a good thing you have talented people working for you.. LOL! As always you didn't answer the question. You need to educate yourself before offering advice..