The Buy Note
A portable speaker is a negotiation between how much air it can move and how easily you can carry it. Almost every other specification is downstream of that one trade, and most of the marketing is an attempt to distract you from it. This piece is about reading the numbers honestly, and about the cases where the right portable speaker turns out to be no portable speaker at all.
Small Boxes and the Bass They Cannot Make
Low frequencies are a volume-of-air problem. To produce a given loudness, a speaker has to displace a certain amount of air, and the lower the note, the more air it takes. Displacement is cone area multiplied by how far the cone travels, so a driver the size of a coin has to move impossibly far to do what a driver the size of a saucer does easily. The cabinet matters too: the air sealed behind the driver acts like a spring, and a tiny cabinet is a stiff spring that fights the cone.
This is physics, not engineering effort, and it sets a floor no brand can talk its way under. A pocket-sized speaker will not produce a convincing kick drum, whose fundamental sits somewhere around 50 to 60 Hz. The low E on a bass guitar is about 41 Hz. Nothing you can slip into a jacket pocket is reproducing that at volume.
What designers do instead is worth understanding, because it explains what you will hear:
- Ports and passive radiators extend the useful response a little by using the cabinet's air as a second, tuned source. Below the tuning point the output falls away faster than it otherwise would, so you gain a bit of reach and lose control underneath it.
- Harmonics do some of the work for free. Given the overtones of a bass note, the ear infers the missing fundamental. A bass line stays recognisable on a small speaker even when the lowest note is simply absent.
- Dynamic processing protects the driver. As you turn the volume up, the speaker pulls the bass back so the cone does not hit its limit. This is why many small speakers sound fuller at low volume than loud, which is the opposite of what people expect.
The practical version: if bass matters to you, buy size. If carrying matters more, accept the trade knowingly rather than hunting for the one small speaker that has beaten physics.
The Battery Number and What It Measures
Quoted battery life is a real measurement of something. It is rarely a measurement of what you are going to do with it.
Amplifier power draw rises steeply with volume, so hours quoted at a moderate listening level do not scale down gently — they collapse. A speaker rated for a long day of background music indoors will manage a fraction of that outdoors, where no walls reflect the sound back at you and the volume has to rise to compensate. Bass-heavy music costs more than speech. Cold costs more again, because lithium cells deliver less when they are cold.
Three things worth checking on the spec sheet:
- Whether the volume used for the rating is stated at all. Some say so plainly; many leave it out.
- Charging. USB-C with a sensible charge time is worth more day to day than an extra couple of rated hours, especially for a speaker you grab on the way out.
- The power-bank feature. A speaker that charges your phone is charging it from the battery that plays your music. It is a genuinely useful emergency function and a poor everyday habit.
IP Ratings, Read Properly
The IP code is two digits with quite different meanings, and it is worth learning because it is one of the few honest numbers in this category.
The first digit is solids, on a scale ending at 6, which is dust-tight. The second is liquids. An X in either position means not rated — untested, not immune. So IPX7 tells you nothing about dust, and IP67 tells you the case is sealed against dust as well.
| Rating | What the certification covers | Sensible use |
|---|---|---|
| IPX4 | Splashing water from any direction | Kitchen worktop, garden, light rain |
| IPX5 | A low-pressure jet from any direction | Poolside, shower, heavy rain |
| IPX7 | Immersion in fresh water, one metre, thirty minutes | Boats, baths, anywhere it may go under |
| IP67 | The above, plus dust-tight | Beaches, building sites, camping in grit |
Three caveats that the rating does not carry. Fresh water is the test medium, so salt and chlorine are outside it and should be rinsed off. Seals age, and a speaker knocked about for two years is not the speaker that was certified. And floating is a separate design decision entirely: plenty of immersion-rated speakers sink, which matters more in a lake than the rating does.
Three Sizes, and What Each Is Actually For
| Size | What it gives you | What it costs you |
|---|---|---|
| Pocket, palm-sized | Goes everywhere, clips to a bag, easy to forget you packed it | Thin bass, limited clean volume, struggles outdoors against wind and traffic |
| Handheld, roughly a large water bottle | The usual sweet spot — real low end, enough volume for a small garden, still one-handed | Too big for a pocket, heavy enough that you decide to bring it |
| Boombox, carried by a handle | Fills a garden or a beach, keeps composure loud, long battery | You take it deliberately, or not at all, and it often lives in a cupboard |
If you cannot decide between two of these, the honest question is not which one sounds best. It is which one will still be leaving the house in six months.
Connections and the Small Annoyances That Decide Whether You Use It
Sound quality gets the attention; the things that make a speaker irritating are almost all elsewhere.
Bluetooth range is quoted in open air, and a wall, a human body or a crowded band takes most of it. Multipoint — holding two devices at once — is the difference between a speaker that follows you from laptop to phone and one that makes you disconnect each time. Latency is worth caring about only if you watch video on it, in which case check for a low-latency mode rather than assuming. A 3.5 mm input is unglamorous and occasionally saves an evening. Stereo pairing of two identical units is mostly a novelty outdoors, where nobody sits in the one spot where stereo works.
The built-in microphone is there for a hands-free call in a quiet room, close by. It is not a conference speakerphone.
When the Cheap One Is Right, and When to Buy Nothing
If the speaker will sit on a shelf, plugged in, playing in one room, a portable is the wrong shape of product. You are paying for a battery, a sealed case and a compromise on cabinet size, all to solve a problem you do not have. A mains-powered speaker of the same footprint will sound better, and a wired one will never need pairing.
If you listen mostly alone, in a quiet home, headphones will beat any portable speaker at the same outlay, and by a wide margin. If the real complaint is that the television is hard to follow, that is a soundbar problem, not a Bluetooth speaker problem.
And the genuinely cheap option is right more often than this category likes to admit. For a shower, a bike, a workshop, a beach where sand and seawater are coming for it anyway, a small rugged speaker is the sensible buy — not because it sounds good, but because the situation destroys speakers and the sound is competing with running water or a power tool. Save the good one for somewhere it can be heard.
