Sennheiser BT T100

Package

In a small square box, Sennheiser supplies (almost) everything you need to connect to the TV or stereo system: the BT T100 (approx. 9 x 9 cm, 85 grams), an analogue mini-jack cable (3.5-millimetre plug, approx. 160 cm long), an optical cable (Toslink plug, approx. 150 cm long), a USB-A to USB-Micro-B cable (approx. 120 cm) and a quick-start guide including safety instructions.

Practicalities

In order for the BT T100 to work, it needs power, of course. It gets it via the USB cable mentioned above, which is connected to an available USB-A socket on the TV, this then supplies the box with 5 volts of operating voltage. Let’s get back to the word “almost” in the package though, because if you don’t have a free USB socket on your TV, you would have to “sacrifice” a USB charger from your smartphone or use a power bank to power the device.

To ensure that the box also receives signals, it is connected either via an analogue mini-jack cable to the headphone socket of the TV or digitally with the optical fibre cable to the corresponding connection. The fibre optic solution is of higher quality and should always be preferred, as the signal from the TV does not have to be converted from digital to analogue and then back from analogue to a digital audio stream. Using the selector switch on the back of the BT T100, you can decide which input source to use, and both cables can remain plugged in at the same time.

That concludes the hardware setup, and all that remains to be done is to connect the BT T100 to a pair of Bluetooth headphones.

For our test, we decided on the following candidates: The Sennheiser Momentum 3 Wireless which have the aptX-LL codec, the Teufel Supreme On which come with aptX without LL, and the Apple AirPods Pro which do without Qualcomm codecs completely. They offer SBC and AAC, although the latter does not come into play in this test, as the BT T100 does not support AAC and therefore chooses the lower-quality SBC codec.

Firstly, we connected the Momentum 3 Wireless to the audio transmitter: To do this, we put the headphones into pairing mode, then we pressed and held the power button of the BT T100 for four seconds so that it too became ready to receive. If the LED of the small box flashes blue and red alternately and then lights up blue for about three minutes, this indicates a successful connection.

Normally, the TV speaker should now be muted and playback will be via the BT T100. Some TV sets, however, output the signal in parallel. It is worthwhile taking a look at the settings of the TV set, as it is often possible to select whether a parallel output should take place or not. If you have connected the audio transmitter digitally and are surprised that you can’t hear anything, you should also consult the TV’s setup and set the audio format to “PCM”.

But back to the listening test: Since the Sennheiser Momentum 3 Wireless uses the low-delay aptX-LL codec, we were curious to see how synchronous the playback was. We zapped through all kinds of talk shows and streaming providers and quickly found out that everything was just fine: Lip movements were always in sync with what we heard, and visually and auditorily at least, we couldn’t detect any noticeable offset on the TV. However, we noticed a slight delay on an iMac that was playing Netflix in a browser, although this was not considered to be that annoying. This changed with headphones connected via aptX (without LL). Here, we noticed a clear offset that was disturbing, and the Apple headphones connected via SBC codec also demonstrated this behaviour – both on the computer and on the television.

This was to be expected and shows for whom the Sennheiser BT T100 is worthwhile: Everyone who wants to watch TV with low latency and has a pair of headphones that supports aptX LL. Or anyone who wants to enjoy high-quality music from their stereo system or PC wirelessly and owns headphones with at least aptX codec.

Those who want to listen to TV or music via headphones as a couple can also do so, because the BT T100 supports the simultaneous connection of two pairs of headphones – but with the restriction that aptX LL will not then work. In this case, the audio transmitter jumps back to aptX or even SBC.

Also, the small box can save the connection profiles of up to eight pairs of Bluetooth headphones, so there is no need to keep pairing with previously connected headphones. If a ninth pair of headphones is added, the profile that has been used the least often is deleted.

One more word about the range: In our test setup, we only heard the first audio drop-outs after about 30 metres of free field; in our living room, the first drop-outs were perceptible after leaving the room (about ten metres).

While the manufacturer also gives instructions on how and where to place the BT T100 so that it can transmit with as little interference as possible, for the purists among us: Sennheiser has made the small box so light that it can easily be attached to the back of a TV with double-sided adhesive tape, keeping TV furniture clear.