Yet until recent times any speaker like this would have to be called “tinny”, because upper midrange and treble was all they could produce.
This one? As I’m typing away right now, “Sunshine of My Love” by Cream is playing. The Flip 4 is four metres away from where I’m sitting, yet it’s producing good, clean music at a moderate volume. Not quite room filling, but probably loud enough to have any co-workers, were there any in this office, protesting for it to be turned down.
There is no kick drum. Not the slightest hint of one. But the bass guitar is full and almost completely reproduced, and in balance with the rest of the music. The rest of the drum kit is equally full, and suffering little compression.
The overall tone is a touch bright, but not excessively so. Vocals are clean and sibilance free. Cymbals are in balance.
Brought up closer, the speaker is accordingly louder but the character remains the same.
That contrast between the bass guitar being present and full and the kick drum being completely absent prompted me to conduct a more formal check to see precisely what was going on. Measuring the full frequency response of the system from about half a metre away showed that the JBL Flip 4 was perfectly happy producing usable output all the way from 60 hertz up to 20,000 hertz. That range was once the preserve of high quality bookshelf loudspeakers.
That said, not all was perfect. The lower midrange was somewhat recessed, while the mid and upper treble – 4000 hertz and up – was somewhat higher in level than the lower frequencies. So, by high quality bookshelf speakers, only so so.
By $150 tiny Bluetooth speaker standards, incredible.
Let’s zoom in a little on that bass end. I remeasured, but this time with the microphone up close to one of the passive radiators to make sure things weren’t being unduly influenced by room effects. The bass had a clear “shoulder” at 62.5 hertz, below which it fell away rapidly. It was down by twelve decibels at 55 hertz, and 24dB by 50 hertz. Those figures just mean that anything at 55 hertz is basically inaudible, unless there’s nothing else playing.
Kick drums have most of their energy at around 40 hertz, which is why they aren’t being reproduced.
This does raise a question I find interesting. Why does JBL say that their frequency response is 70 to 20,000 hertz? It could legitimately say 60 to 20,000. And it has far better measurement facilities than I do.
Perhaps it figured that no one would believe it if that was its claim, whereas 70 hertz, while still impressive, would be more plausible.
You’re very unlikely to do better for the price for a compact, portable Bluetooth speaker than the JBL Flip 4.