Koss BT740iQZ

Bluetooth over-ears with Active Noise Cancelling

BT740iQZ – A somewhat unwieldy name for what are actually quite elegant headphones that the designers at Koss have come up with for their new Bluetooth model. With active noise-cancelling (ANC), integrated media control and hands-free function, as well as long battery life, these new over-ear headphones are designed to be a convenient audio accessory for all situations.


Koss has equipped the BT740iQZ with their tried-and-tested 40 mm drivers, whose frequency reproduction ranges from 10 Hz to 20 kHz according to the data sheet and which are capable of a peak sound level of 97 decibels. Audio material can be transmitted to the headphones either wirelessly via Bluetooth or via the mini-jack socket integrated into the right-hand side. The right earpiece is obviously in command, as it also houses the media control, the charging port (micro-USB) and the button for noise cancellation.


Unfortunately, Koss have kept mum on the nature of the technical specs. However, the system controls of my Android and iOS players showed that SBC was the connection standard. This means that the Koss headphones not only support audio playback, but also hands-free telephony. In addition, the headset also supports multipoint pairing and can be connected to several devices at the same time. In practical terms, this means that the BT740iQZ are displayed as available in every Bluetooth device involved. However, the audio stream of the different devices is not mixed – instead, a “first come, first play” rule applies. If you stop playback on one device and start it on another, the system switches to the next player after a pause of one second.

Charging is done via the integrated micro-USB socket and a full charging cycle takes about 2.5 hours. The BT740iQZ then rewards you with a very respectable battery life of around 30 hours – which should be enough to cover one or two trips in local and long-distance journeys. The range of the Bluetooth connection also proved to be very good. While some devices we test sometimes have difficulties transmitting from one corner of a room to another, with the Koss, I was able to move around the flat within a radius of 10 metres (with two walls in between) without any problems.

These headphones are operated via the function buttons integrated into the right-hand side of the headset. There are three buttons that handle the commands for music play/pause, next/previous track with the secondary function of volume up/down. The middle multi-function button can also be used to switch the headphones on and off and, with a quick double press, call up a voice assistant on a mobile device (e.g. Siri or Google Assistant).

A fourth button, located slightly lower, controls noise cancellation activity. Pressing it several times switches between the three options “ANC off”, “Low”, and “High”. A short tap switches on the ambient sound mode, which then allows ambient noise to pass through again. The algorithm at work here does a good job: even in the “Low” setting, it noticeably reduces subtle ambient noise – or makes it inaudible. In the “High” setting, the algorithm goes one better and is able to significantly reduce sources of interference such as street noise, engine noise or the babble of voices. I live next to a busy road and usually work with the window closed to improve concentration. As I write these lines, I am wearing the BT740iQZ and can report that the noise protection – even with the window open – is pretty impressive. The only fly in the ointment is that the noise cancellation also colours the sound. In the maximum setting (“High”) in particular, it is accompanied by a noticeable loss in the bass range and spatiality. For me, this setting seemed ideal if what you really want is to have “peace and quiet” while not listening to music. When listening to music at the same time, the “Low” setting seemed quite sufficient, as some noise is masked by the music (which of course always depends somewhat on which music you’re listening to).

The BT740iQZ can be worn for long periods and this is due to the good fit, which maintains a pleasant balance between a firm hold and unrestrained pressure on your head and ears. The closed design inevitably means that after a while you get the usual feeling of a slight build-up of heat on your ears – but unfortunately, there’s nothing you can do about that. That’s just the way it is with closed headphones. This also applies to wind noise, which is inevitably transmitted to the ear (and this has been criticised on some headphone forums). To check this, I went for a walk along the Rhine on a stormy day with the Koss and two other closed headphones and found that the wind was basically equally noticeable in all the headphones. What might have led to the criticism of the Koss is the fact that its cabinet resonance is relatively high in frequency and thus lies more clearly in the frequency-sensitive listening range. As an aside, I think that the BT740iQZ would be much better suited to use in the office, for multimedia and home listening due to their design, and less so for use as an accessory for outdoor hiking.

If you don’t have a Bluetooth player on hand or want to operate the BT74,iQZ with the headphone output of an amplifier, music can also be transmitted in the traditional way with “audio cable to Koss headphones”. Simply plug the mini-jack cable into the corresponding jack on the right-hand earpiece. However, this only works if the headphones are charged, because they switch on automatically when you plug in the cable. The advantage of this is that active noise cancelling is also available during wired use. I did not notice any difference in sound quality between the wired and Bluetooth connection.

Once you’ve finished listening, the headphones can be folded away, making the BT740iQZ easy to store in their carrying case, which comes with the package.



The Koss conjure up a cosy sound that was pleasant to the ears. The main focus of the sound is less on treble sparkle and transparency, and more on building up a decent bass foundation and providing mildly rounded low-mids. All in all, this creates a very pleasant, warm and harmonious sound that – together with the noise cancelling – helps to keep stressful noise at bay. The Koss are therefore ideally suited to what I like to call the acoustic “sofa” – a cosy, soft and warm sound that you would like to fall into. They are less what I would call a “workhorse”, in the sense of being headphones that illuminate every detail with surgical precision.

I would also like to mention that the sound quality of the integrated microphone is surprisingly good, making even long phone calls or video conferences quite bearable for the person on the other end of the call.

2 years ago by Numinos
  • Rating: 4.38
  • Sound
  • Handling
  • Price/Quality
  • Function

The Koss BT740iQZ got through our test without any slip-ups, and for a reasonable price, you get a pair of Bluetooth headphones that are decent in every respect (sound, wearing comfort, handling) with effective ambient noise cancellation. Their sound profile is aimed more at listeners who are looking for a warm, soft and bass-strong “cuddly” sound and less at fans of crystal-clear, precise and treble-rich sound.

Measurement Results

Frequency response:

Exterior noise damping:
More measurement results

Technical specifications

  • Ear couplingOver-ear
  • Typeclosed
  • Transducer principledynamic
  • Frequency response (headphones)10 - 20.000 Hz
  • Sound pressure level (SPL)97 dB
  • Weight without cable280 g

What's in the box

  • Mini jack cable
  • Micro USB charging cable
  • Carrying pouch

Special features

  • BT codecs: SBC
  • BT version: 5.0

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