Phone Speaker: Watts and Decibels Across Different Models

I recently bought a new phone – the iPhone 14 Pro, put it side by side with my 13 Pro, and I noticed that it sounds much louder and better.

Also, the Dolby atoms stuff sounded more spaced out.

I never actually checked how much wattage the phone speaker puts out. I was also interested in decibels, at least approximate numbers.

After all, these phone speakers are not even that bad! On the contrary, they’re excellent, considering the size.

It turned out that that data is not easy to dig online. Manufacturers rarely give that data in specs; when they do, it’s buried somewhere between lots of other useless information.

I decided to test some of the models myself, and along the way, I found out how phone speakers work and some additional cool info about them.

In this article, I’ll reveal everything I learned about phone speakers, their specs, quality, and loudness.

How Many Watts Is a Phone Speaker?

Phone Arena asked readers if phone speaker quality mattered to them, and the results were exactly what I was expecting.

There were 2638 votes, and 79.08% said that speaker quality matters to them and that they want a better phone speaker in the future. Only 15.54% said that speaker quality doesn’t matter to them, and 5.38% were neutral.

That says a lot. But is speaker quality really determined by their wattage?

Watts are not a measure of loudness, hearing quality, or clarity. Power and loudness are not the same.

The sound quality and the loudness rely on many specific conditions, even more influential than just the power defined in WATTS. Therefore, although the sound will be louder, it won’t have the clarity to be audible and pleasant.

What do you want to get, sound or noise? Clear, crisp, and enjoyable sounds will sometimes be annoying and stressful at the same wattage.

That being said, if you still want to know what the wattage the phones today carry, I managed to dig up numbers for the popular models.

The wattage of phone speakers ranges between 1.5 W for a bit older models and 3 W in newer and higher-end models. 

How about decibels?

The decibel ratings depend on a number of factors, like the size and quality of the speaker, the placement of the speaker within the device, and the materials used.

In general, the decibel levels produced by smartphone speakers range from around 85 dB to 93 dB, depending on the specific model (newer models – more decibels) and the conditions under which the sound is being produced. 

As many factors are included, here we need to do an estimation. Here’s a table of some popular smartphones, along with an estimated decibel output:

Main Reasons Why Phone Speakers Are So Loud

1. The phone cuts off most low frequencies below a specific limit.

With every lowering of an octave (half the Hz), a speaker diaphragm has to move four times the distance for equal volume.

So by trimming off the bass, they can get more perceived volume from a smaller unit.

2. Phone speakers are actually very quiet compared to proper speakers;

We just don’t perceive it to be very quiet if the environment is quiet.

For example, a water kettle is not very loud; you can still talk to someone over the noise it makes. But it completely drowns the sound from smartphone speakers.

This is because we have a very high dynamic range, as I learned from Wolfgang Klippel, who is the oracle on all the definitive fundamentals in loudspeakers. He lays it all out in his app note AN24, which you can find at klippel.de.

That means we can hear extremely quiet and excessively loud things well without ever noticing their differences.

If there is a 20dB increase in sound pressure between a phone and a proper speaker, we will think that the speaker is just a bit louder than the smartphone. But it actually is 100 times as powerful.

3. The most considerable help phone speakers get is DSP (Digital Signal Processors).

Putting an un-modified audio signal through the phone speaker on a bench will sound terrible.

But if you take the speaker’s frequency response into account and do some clever enclosure design, then compensate for the speaker’s non-linear response and boost the output levels in the frequency bands the speaker does poorly in, you will make a fuller, richer-sounding speaker even if the actual speaker is terrible.

This is what all the decent manufacturers do across the board and why these modern, tiny little Bluetooth speakers sound pretty decent even though they’re small.

DSP is the special sauce, the actual speaker is a minor factor, and they are often quite bad by themselves without help.

4. The amplifier also matters.

Often, the speaker’s electrical/frequency response will be well characterized and paired with amps with more sophisticated sensing capabilities (look into “smart amps”).

You can optimize the amplifier output to drive the speaker to excursion and power levels that would destroy an average speaker; however, you are safe when the speaker’s properties are well understood.

If you try driving that tiny speaker with a standard amplifier, it will be quieter than it usually is on the phone.

5. They often use an acoustic ‘trick.’

They add tiny polystyrene balls in the cavity to increase the apparent size of the resonance chamber, increasing the volume and bass levels.

I pulled one open once and was surprised to unexpectedly have 100s of sand grain-sized white balls everywhere.

Essentially they’re packing cotton wool inside a woofer, so instead of one prominent resonant peak for the chamber, you get a smoother bump across a broader spectrum.

Speaker fill causes the sound waves to propagate more slowly through the material, making the space effectively larger.

A synthetic material that looks like cotton is traditionally used for regular home speakers, but more advanced materials are used for high-tech and tiny speakers like phones.

This material also eats a little power, but that’s considered a fair trade for better sound quality.

Drivers in Phone Speakers vs. Regular

First, an explanation. A speaker refers to a device that was developed to play audio. That includes the whole box and everything in it.

A DRIVER is an individual component that creates sound. It is a part of the speaker – a transducer that converts electrical energy to sound.

For one thing, traditional 2-way speakers are exactly that: two ways.

What that means is that most speakers you encounter in the world that are even designed to sound halfway good (such as in a movie theater or ones you might buy from Amazon) have at least two drivers: 

• One that handles low frequencies
• One that handles high frequencies.

A device called a crossover determines at what point one stops and the other starts (this is actually a gradual process, happening over a few octaves).

The advantage of this is that you can ‘tune’ a driver for its intended purpose.

A larger driver will be better for low frequencies but bad for high ones because it is hard and takes more energy to move a big thing quickly.

A smaller driver (like the one in the phone speaker) will be good at moving quickly because it’s small but not big enough to move the air to create a lower frequency.

Remember, to produce the sound of the human voice, you must move a driver back and forth between 1000 – 4000 times in one second.

This is an ideal range for a phone speaker.

So, the speaker in a phone which is mainly designed to reproduce the human voice, will be adjusted for these frequencies.

Yes, the speakers in a phone are primarily designed to make speakerphone work. A bonus these days for engineers is that everyone is happy jogging and listening to speakers the size of dimes. 

No effort is required to make consumer electronics sound good.

You can think of music as needing a speaker to vibrate from 20 times in one second (reasonably slowly) to 20k times in one second (Really fast). That’s a much more extensive range!

It’s hard to make a single driver that can cover that range, so you employ two.

The trade-off to using a 2-way speaker is that you will experience some distortion around where the frequencies crossover, known as phase cancellation. Engineers of such systems employ plenty of electrical tricks to try and minimize this effect and some physical techniques.

Also, you could extend the range of a driver by porting the cabinet it’s in, which of course, causes comb filtering – another trade-off.

The speaker design is really complicated and very cool. Also, the amount of optimization in a modern phone is ridiculous.