Blafili RTX

Blafili RTX - A surprisingly useful audio transmitter / receiver

Introduction

I have been playing with the Blafili RTX for the past few weeks, looking it how it could be integrated into my home audio setup and I impressed with the different use-case I came up with for this device. I was especially impressed with what it can do for $59.99.

So I thought I would share my opinions and the details of how you might use this device in your own setup.

So just to explain the concept of the RTX, I thought this is a useful introductory diagram from the blafili Website, you connect an audio source to the transmitter, and its wireless broadcasts this audio to one or more receivers (up to 4 receivers in your house) which can be connected via RCA inputs to device to play that audio:

It could be thought of as a small DAC within the transmitter with a really long ‘invisible’ RCA cable to a receiver to play the content.

Packaging and Unboxing:

The Blafili RTX comes in a nice box containing 2 smaller separate boxes, one for the Transmitter and one for the Receiver:

Opening both boxes reveals the tiny boxes:

Transmitter

Looking at the transmitter it has a nice clean look a bit of detail we see that it has multiple inputs, with USB, Optical and RCA inputs.

Internally the DAC will convert the USB and Optical to a respectable 16bit/48khz which considering it will then be transmitting this over its range of 30m / 100feet with low latency it makes sense to limit the bitrate used.

Here is a short video showing the Transmitter in detail from all angles:

Receiver

The Receiver is simpler with its connectivity options, with just the usb (for charging only) and the RCA outputs: And a similar video of the Receiver:

Specifications

The internal DAC within the Transmitter is a modest affair (but good enough for most use cases) though the optical input can only accept 44.1kHz signals but here are the key specifications:

Use-cases

So my primary motivation for using the RTX is the ability to not have wires visual. My wife hates wires which in a house with lots of gadgets is definitely a problem. This has in the past limited what I can do in most rooms in my house, though I do have a ‘den’ where I am allowed to play with stuff.

So I thought I would share 3 simple use-cases where the RTX can be used to greatly enhance my setup, while still having a large ‘Spouse Acceptance Factor’ with no wires visible.

Wireless Subwoofer in secondary TV Room

So here is my photo of my second TV Room:

It used to be the ‘kids’ playroom but since they have grown up a bit we now all swap around depending on who is watching what in my house. I often end up here watching football and even listening to music while the main living is used for Soap opera’s and Movies.

As you can hopefully see I have a WiiM Amp setup with HDMI inputs from the TV to the Q Acoustics 3020 speakers, mostly I like this simple setup, it has fantastic sound compared to a soundbar, the WiiM Amp has some PEQ to do basic room correction and also a subwoofer output, but as you can see there is not space for a Subwoofer, this is where the Blafili RTX can come in.

Connecting just one of the RTX transmitter RCA input to the subwoofer output of the WiiM amp:

And then on the other side of the room I have a ‘hidden’ Subwoofer behind the couch. The RTX receiver can then be used to connect the signal into the subwoofer:

Then I have much more flexibility about subwoofer placement within the room and can use the subwoofer management within the WiiM Amp mobile app to adjust the subwoofer output.

Remote Turntable into TV Room

Another use-case where the RTX could be used is also in this same room as I have a turntable but no space to put it near the WiiM Amp, previously I would have a long RCA cable strung around the fireplace into the back of the WiiM Amp the RTX gives me a simple option for the turntable:

So with this use case I am connecting the turntable as the transmitter - this Audio Technica turntable has a built-in photo stage, so I can just connect the output directly into the RTX transmitter:

Then use the receiver with the WiiM Amp to connect the RCA inputs into the back of the WiiM Amp:

The RTX receiver is hardly noticeable on top of the WiiM Amp:

Now I can leave the turntable where it is and start playing a record and use the WiiM Amp Mobile App to switch its input to the RCA input and listen to the music. I found the broadcast quality of the RTX in this specific use case was perfect with no noticeable loose in quality over its wireless signal compare to the long RCA cable I used previously.

Denon AVR wireless “Zone 2” to Bedroom / Office speakers

So one other simple option I came up with, is my Denon AVR receiver in my ‘Den’ has a Zone 2 which is a stereo preamp on the back of the AVR via an RCA outputs. So simply putting the Blafili RTX Transmitter in the cabinet with the Denon and connecting the RCA output into the Transmitter allows me to have the Denon output to anywhere within my house.

And I have a pair of nice FiiO SP3 speakers in one of the bedrooms’ desks and while previously these speakers are normally only connected via a PC, but they have a second input on the back and an input switch:

So it was super handy to connect the RTX receiver inside the desktop and feed the RCA cable from the Receiver into the back of FiiO SP3:

Now I can use the speakers even when there isn’t a laptop connected to them and I can use the Denon Heos streaming app to easily stream audio to this room in the house.

Sound impressions

Overall for the price and the capability it enables I was very impressed with the sound quality. It not super detailed but easily good enough for the 3 use-case above, I also did some more extensive testing with the audio quality in ‘difficult’ situations and some distance testing.

Bass, Midrange and Treble

Rather than separate sections, it is fair to the RTX is transparent so does not change the Frequency response. I did feel when used on a middle distance (from my Denon to the Office Speakers) that when doing some A/B testing between the wireless and a wired connection there was a slight loss in resolution over the wireless connection. I believe this is because of a slightly higher noise floor which probably takes away the sharpness of the sound.

Range affects quality

So it might sound obvious, but I tried playing some specific test tracks in different distances to test how the performance changes. I had no problem setting the receiver up near the front of my large 4-bed house and the transmitter upstairs at the back and the audio was clear but as I mentioned above possible lots its sharpness. But for casual listening to music around your house even through multiple walls within my house the audio was steady and very enjoyable.

But when I had both the transmitter and receiver across the same room the quality was indistinguishable from a cable, this would be my main use case - allow my turn table to be setup wireless transmitting to my amplifier. To test this I tried the classic (John Cage 4.33 recording)[https://open.spotify.com/album/6UCnARt06DDqBASaO8sBaz]
if there is any noise introduced into the signal you will not hear the ticking clock or any of the door openings and other really high dynamic range artifacts from the audience over the tape hiss, but I upped the gain on both the transmitter and receiver ends I could hear everything that I would expect, hence why I thought the turntable was an excellent use case for RTX when your room has constraints.

Finally, with range I tried to see how far it would transmit the audio, for this test I had the same tracks playing from my external garage - itself about 10 meters from the house to the front of my house, well beyond the 30m and while it worked the audio quality was greatly reduced, with some audible noise artifacts clearly heard. So Blafili are pretty accurate with their range specifications.

There I would advise staying within the 30m max, and ideally I think use it internally within a room to remove wires or between adjacent rooms.

The ‘microwave’ test

Recognising that the RTX uses the same 2.4Ghz range as many other devices (including Wi-Fi and Bluetooth) I thought I would see how it copes with one of domestic devices that can cause issues to all these protocols, your microwave. So I repeated the in-room test and the intra-room test and with the in-room test the microwave did not affect the signal but with the intra-room (from downstairs in my house to upstairs) I found that the signal was affected when the microwave was running, basically just little bits of ‘analog noise’ added to the signal, this disappeared immediately once the microwave was finished.

Rating

I have rated the Blafili RTX with a pragmatic rating of 4, for $59.99 you do not expect much yet the RTX can provide simple solutions to routing audio around your house with a high “Spouse Acceptance Factor”, this alone makes it a very valuable audio ‘gadget’. I would not recommend it in your ‘primary’ audio stack (actual cables will always be better) but when space and running cables is an issue as it in most of my house, this device provides lots of unique ways to keep everyone happy.

Conclusion

The Blafili RTX is the type of device everyone should have in their toolbox, we cannot all design our rooms around our audio setup, sometimes you need the ability to get the maximum functionality with the cleanest looking setup and the RTX certainly provides the ability to provide a clean looking setup.