Panasonic RZ-S300W

True Wireless In-Ears with Ambient Sound Mode

The new RZ-S300W True Wireless in-ears are the smaller and cheaper “little brothers” of the RZ-S500W which we recently tested, however, among other things, they do not come with noise cancelling. So is the saving of fifty Euros worth it?



Available in the three colours Deep Black, Dusty White and Mint Green, and IPX4 splash-proof, the RZ-S300W comes with four pairs of silicone earpieces in sizes XS, S, M and L and a 50 cm USB-A to USB-C cable. Various information leaflets in different languages are also included. A small but subtle difference: While their noise-cancelling counterpart RZ-S500W comes with five pairs of earpieces, the 300s lack a pair in size XL. If you need extra large, you’ll have to get an extra replacement earpiece.

Wearing comfort


You will be rewarded with a very good passive isolation as well as a comfortable fit, but only with the right earpieces. At about 4 grams per earpiece, these are hardly noticeable when you’re wearing them, so the RZ-S300W is one of the lightest headphones of its kind. At the same time, they are so slim that cap wearers will barely suffer from any complaints about pressure. As with its big brother, there is nothing to criticise in the workmanship of these headphones. The same also goes for the 45-gram transport case, even if, due to the plastic used, it doesn’t seem quite as good quality as the earphones.

Running times

These earphones have lithium polymer batteries with a capacity of 55 mAh and run for between seven (with SBC) and seven and a half hours (with AAC) depending on the codec selected. Like the RZ-S500W, they can also be operated individually in mono mode. The charging case can recharge the 300 up to four times, resulting in a total running time of up to 30 hours. Panasonic has also come up with a quick charging function: After fifteen minutes of power on, the case gives you about 90 minutes of listening time. The battery (Lithium Polymer 800 mAh) in the small charging case, which except for the charging recesses is identical to the RZ-S500W case, can be charged via USB-C connection. The manufacturer states four hours for this, but in our test, the charging case had already reached its full capacity after three hours and 25 minutes.


The first pairing of the Panasonic RZ-S300W takes place when the headphones are removed from the case. If you want to connect the already paired in-ears to another device you must first disconnect the first player, and then press one of the two touch surfaces for seven seconds within three seconds of removing the headphones from the case (as multipoint is not supported).

In our test with different Android and iOS devices, we were also able to achieve extremely stable ranges with this model: In an open space, the first drop-outs could only be heard after about 35 metres, while inside an apartment we did not hear any drop-outs even across one storey.

A simple tap on the left side is used to control the Play/Stop function. A quick tap on the left side two or three times lowers or raises the volume. Holding the left touch sensor for two seconds starts the familiar voice assistants (including “Alexa built in”), while the right headphone allows you to jump back or forth through titles by pressing two or three times. It is also possible to answer calls by simply touching either side, while ending a call requires a two-second press and hold.

Controlling with the touch surfaces always worked perfectly with a delay of around one second, and the variety of controls available directly on the headphones left hardly anything to be desired, so all the important functions are covered by the RZ-S300W. But the same thing that applies to their big brother, the RZ-S500W, also applies here: I would have liked to have a touch lock so that when adjusting the extremely small earphones, accidental triggering of functions could be avoided.

App Connection

With the free app “Panasonic Audio Connect” for Android and iOS you can make some fine adjustments via your Smartphone: Here can you use a five-band EQ in “sound mode” as well as sound presets for “bass optimization” and “clear speech intelligibility”. It’s worth noting that changes to the EQ are saved, but you cannot create several presets. The most important settings in the app depend on whether you want to prioritise sound quality (using the AAC codec) or connectivity (set the codec to SBC) and after how many minutes an automatic shutdown should occur. Another useful feature is the find function: The headphones attract your attention by beeps or can be found on a geo map.

Compared to the RZ-S500W, what is missing: The transparency mode can only be deactivated and activated, but there is no variable control. Indeed, this does work very well, although it doesn’t come close to the naturalness of Apple AirPods Pro. Activation is also accompanied by an increase in background noise, however, this is masked during music playback.

These in-ears do not actively suppress structure-borne noise, but this is not particularly pronounced in this model and therefore is not necessarily disturbing.


While we enjoyed the modern, low-end sound of the “big” RZ-S500W (8 mm driver) in our test, the acoustic tuning of the 300 (6 mm driver) takes a different direction. Straight out of the box, they sound unspectacular. This is a pity, as prospective buyers who would like to have the sound aesthetics of the 500, but in a cheaper version with reduced features, might be disappointed. In fact, the RZ-S300W differs quite clearly from the model which includes noise-cancelling: The bass range reaches the ear in a reserved and sober manner, real low bass is missing, although this model does reproduce bass drums and instruments cleanly. The mids range from inconspicuous to slightly forced, and some pieces in our playlist showed a slight tendency to overemphasise the upper mids. This continues in the high frequencies so that hissing hi-hats like in Rihanna’s “Umbrella” can quickly lead to fatigue at higher volumes. The instruments also stand close together on the imaginary stage and their depth is not very pronounced. Due to their construction, this is a difficult task for in-ears, but this problem would not be unsolvable. With these above mentioned characteristics, the RZ-S300W simply sound insanely direct, which guarantees very good speech intelligibility, especially with spoken content.

In this model, however, the speech quality of telephone calls leaf us with mixed feelings: The caller understood us moderately to well when we talked on the phone, but in windy condition the noise suppression of the microphones sometimes caused words to be cut.

Pete Schloßnagel
1 year ago by Pete Schloßnagel
  • Rating: 3.88
  • Sound
  • Handling
  • Price/Quality
  • Function

Panasonic’s first attempt at the “RZ-S300W” can be described as “well done”: For a recommended retail price of just under 120 Euros, there are very good runtimes and very good ranges packed into light in-ears which weigh just four grams. However, if you were hoping for the modern sound tuning you get with the RZ-S500W, you will be disappointed: The small RZ-S300W doesn’t sound as full of character, the sound is much more sober (which doesn’t have to be a bad thing) and with a slight overemphasis in the treble, which can be a bit too much with some music.

In conclusion, very good noise cancelling and a continuously adjustable transparency mode are not the only things that you are missing out on in exchange for a saving of fifty Euros.

Technical specifications

  • Ear couplingIn-ear
  • Typeclosed
  • Transducer principledynamic
  • Frequency response (headphones)20 - 20.000 Hz
  • Impedance32 ohms
  • Weight without cableIn-ears: 8g; incl. case 41 g
  • Cable length50 cm

What's in the box

  • 4 pairs of ear tips in XS, S, M, L
  • USB charging cable
  • Charging Case

Special features

  • available in black, white and green
  • BT codecs: AAC, SBC
  • BT version: 5.0
  • BT profiles: A2DP, AVRCP, HSP, HFP

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