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Boult audio airbass Z40 review

Boult audio airbass Z40 true wireless earbuds is the latest product from boult audio. Did boult audio make it sound better? We are going to see the full review of boult audio Z40. I will keep this review short and sweet. Let’s dive in.

There is a successor to this earbuds. If you’re a serious bass head, you can consider it instead of Boult audio airbass Z40. For others you will be better off with this one. You can check out Boult audio Z40 pro review for more details.

Boult Audio airbass Z40 review
Boult Audio Z40 Review

Boult audio airbass Z40 TWS

4.1 out of 5

To summarise, Boult audio airbass Z40 is a nice pair of true wireless earbuds or TWS earbuds. Boult audio airbass z40 has great bass and a good soundstage. But it has its own drawbacks that it will not be suitable for some if not many. I have explained about it, Its sound quality, listening experience, and every other thing in the article below.

Build quality
4.5 out of 5
Sound quality
3.5 out of 5
4 out of 5
Battery life
4.5 out of 5


Easy to use

Bass heavy

Good battery life

Fast charging

10 mm driver



Mids are bassy

Only Bluetooth V5.2

The treble is rolled off.

Appearance – Boult audio airbass Z40 review

Boult Audio Z40 review
Boult Audio Z40 Front

The Boult audio airbass Z40 true wireless earbuds looks great in real life. I chose to go with the blue colour and it paid off. In India, you will get boult audio airbass z40 in other colors as well. ‘BOULT AUDIO’ is written on the Lid, and there is a small LED status indicator below the lid opening. Overall, the body is rounded and beautiful.

Boult Audio Z40 SIde view
Boult audio airbass Z40 Side
Boult Audio Z40 Side with lid open
Z40 side with lid open

The Boult audio airbass Z40 equally looks good on the side too. The Lid closing gaps are tight, and the boult audio airbass z40 invites a second look. The sides of these earbuds with charging case is rounded. The Lid of boult audio airbass z40 true wireless earbuds closing lines takes a peculiar style. Nice one!

Boult Audio Z40 backside
The Z40’s Back

The backside of these earbuds with charging case is plain and simple. There isn’t anything except for a hinge. Back side is also rounded to give a nice look

Boult Audio Z40 bottom side
bottom side of Z40

On the bottom of boult audio airbass z40, there is a USB Type C port. It is used for charging this boult audio airbass z40. Yes, It supports fast charging. More on it later in the article.

Boult Audio Z40 Lid open view
The Lid of Z40

The Lid of Boult audio Z40 true wireless earbuds opens to reveal the earbuds. It is snugly packed inside the case with magnets to keep it in its place. The earbuds have tiny LED lights to tell about the status of their charge.

Picture of Boult Audio Z40 earbuds
Pair of Z40 earbuds

The earbuds of Boult audio airbass Z40 look nice and have good quality. The rubber ear tips are also good quality. They can comfortably place themselves in the ear. There are mics around to capture audio and also to make ENC noise cancellation. We have explained it in the later session of the article.

Build quality

The build quality of the boult audio airbass Z40 is fine. The earbuds with charging case look premium and are made of nice plastic. The lid won’t wobble like Z25. The lid is also decently made. It feels premium for what it is being offered. 

So, I have no complaints about build quality. You will be fine with it.


Pairing the Boult audio airbass Z40 with other phones is easy too. Open the lid and take the earbuds out and you can see it listed in available Bluetooth devices in the phone. You can tap it to pair it instantly. If you’re connecting the second time, you need to open the lid and take out the true wireless earbuds, and the earbuds will be connected automatically to the phone.


I had issues with the fitting of the boult audio airbass Z40 in the ear with default ear tips. With that in place, I didn’t get a proper seal, and also, the bass was lacking. I changed to larger ear tips, and the earbuds fitted well in the ears. I had to insert the ear tips without hurting the ear as the ear tips were big enough for me. Thank god for not the earbuds are too big. I wish, the neck is a bit longer so that the ear tips would go deep into the ear canals.

I also had an issue. Pushing the earbuds in the ear makes a crackling driver sound. Like crumbling the driver. It is due to the pressure and it also gives a suction feeling.

Sound quality of Boult audio Z40

I would say that the sound quality of Boult audio airbass Z40 is decent in my ears, especially for the price in India it is offered. Boult audio airbass z40 is a warm-sounding earphone with a lot of bass if you can wear earphones properly so that you will get a good fit with the ear. It has a bass-heavy sound signature.

The sound stage is wide and I have no complaints there. The dynamics aren’t its forte. But for this price in India, you can’t expect more.


The Bass of boult audio airbass z40 is great. It does hit 20 Hz but the volume is a little low. in fact, there is great progress above 45 Hz, and I don’t have many complaints. It uses a 10 mm dynamic driver. Hence the bass will be plenty.

If you push it into the ear, the bass is definitely better. But, it might damage your hearing, and also it gives a suction feeling. No holes for the pressure to stabilize. Mid-bass is great too. Since it has a big driver, it could pump out more bass. The bass is pleasing too. For the price range it is offered, it is one of the best in India.

The Boult audio airbass z40 has the bass-dominating sound signature. Wish the bass was a bit less on mid-tones. You can listen to these true wireless earbuds for a long time without any fatigue.


The Mids of Boult audio airbass Z40 has the colouration of bass. It sounds bassy. The Mids is a bit weak. It could have been better. It might not be an ideal choice for audiobooks and podcasts. The resolution is also weak. It is like having a veil in front of the speakers. All the mid elements have bassy nature. Yes. The mids could have been better. 


The treble of Boult audio airbass Z40 is rolled off. Hence, it is a warm-sounding earbud. In fact, it is rolled off so much that it is somewhat dark sounding. The clarity and sparkle are missing. The treble has good extension. But the volume is less, so I said it is rolled off. You have to search for details. However, you can listen to songs for a longer period of time without any ear fatigue. Hence, this is a plus.

Listening impressions 

Turn down for what. By DJ snake

I pushed the boult audio airbass z40 earbuds inside the ear canal until it sealed my ear canals and played this song. It has great low bass and strong mids. The bass was great. It punches well. The song is especially for testing the bass and with the true wireless earbuds, I am satisfied with the bass. The mid-bass is also nice to hear.

Money by Pink Floyd.

It is also dark sounding but the song could unearth details. The song has many treble elements like coins shimmering and those didn’t come out with absolute clarity from Boult audio airbass z40. Even the cymbals were subdued. The song has a nice trumpet solo and wish the mids were better. The soundstage is great. The plugged bass has a slight hint of bloat but not a real problem, IMO.

I’m not the only one – sam smith

In my opinion, this track is an ideal test track for boult audio airbass z40. The start of the song has a punchy bass drum kick. It is rendered strongly. But the accompanying bass wasn’t that tight. Sam smith’s vocals are a little dark and the earphone made it even darker. No hint of airiness in his voice. The treble is weak too. The voice also goes into backstage of the mix as the bass is prominent and overpowering in many places in the song.

Call quality

The call quality of boult audio airbass z40 is decent. Since the mic is recessed compared to wired earphones or neckbands, the audio will be picked up less in a TWS. Also, this boult audio airbass z40 true wireless earbuds has ENC, meaning environmental noise cancellation, and that enhances the sound by reducing the noise. This way, the person on the other end of the line will hear better audio of yours.


Boult audio airbass Z40 has the usual features which are found in other true wireless earbuds of the same budget. Nothing is new here. I will list out some of the good features it has.

  • Bluetooth 5.2
  • Low latency gaming
  • ENC
  • IPX5 water resistance
  • 10 mm driver
  • Haptic Touch controls
  • Voice assistants support etc.

Battery life

The battery life of boult audio airbass z40 is very good. It is one of the finest in India. With a full charge, it can give up to 60 hours of playback time with both the case and true wireless earbuds combined. The 60 hours quotation is in the test condition. Still, it is great. In addition, these TWS earbuds have fast charging through a USB C port. 

With 10 minutes of charge, the TWS can give up to 100 minutes of playback time. Excellent!

Boult audio airdopes Z40 review

Boult audio Z40 review


  • Frequency response: 20Hz to 20000 Hz (as per the info)
  • Battery life: 60 hours
  • Bluetooth version: 5.2
  • Fast charging: Yes
  • IPX5 rating
  • Range: 10 meters
  • ENC: available
  • Gaming mode: yes

Pros and cons

  • Looks cool
  • Bass heavy
  • Good battery life
  • Fast charging
  • 10 mm driver
  • ENC
  • Mids are bassy
  • Only Bluetooth V5.2
  • The treble is slightly rolled off.


To summarise this Boult audio airbass Z40 review, it is a nice earphone, especially for bass heads. For the price in India, it is one of the best. It pumps out a good quantity and quality of bass. For someone who wants a neutral sound signature, it isn’t the TWS you would be looking at. For bass heads along with Boult audio Z25, Z40 is also a nice choice.

It is, in fact, one of the best TWS earbuds under Rs 1500.

You can check the price in India and buy it from amazon by clicking the button below

Check the price on amazon

You can directly buy it on amazon by clicking the button below

Buy now on Amazon

Thanks for reading.

PS: if you like to visit the manufacturer’s website, you can click here: Boult audio Z40

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