[Merkurio]

Price at launch:
$299 USD​

Specs:

• NXP iMXRT600 ARM + DSP Core
• Four ES9219C SABRE HiFi® DAC
• Two Texas Instruments INA1620 AMP
• Unbalanced output max. 4V RMS (3.5mm)
• Balanced output max. 8V RMS (2.5 & 4.4mm)
• 4~10 hours battery time (1000mA Battery)
• 2.0 Channel Stereo Mode 384KHz / 32-bit
• 7.1 Channel Surround Mode 96KHz / 32-bit
• 20-Band Equalizer
• Two High Sensitivity MEMS Microphones
• PC Chrome App Windows/macOS/Linux
• 84 x 40 x 1.6mm / 75g
• Aluminum CNC Body / Plastic Bottom case

The Qudelix-T71 is a USB DAC (Digital-to-Analog Converter) that is designed to receive and process multi-channel audio from a host source device. Unlike most conventional USB DACs that only receive two-channel stereo audio, the T71 can receive up to 8 channels of digital audio.

The T71 is equipped with a high-performance Digital Signal Processor (DSP) that utilizes a proprietary algorithm to process the incoming multi-channel surround audio. It mixes the audio channels into the appropriate speaker format based on the connected speakers or headphones.

One of the features of the T71 is its ability to automatically detect the incoming audio channel format. The device's screen displays real-time channel information of the incoming audio. This information shows the format, such as 5.1 Rear, 5.1 Side, 7.1, or 2.0 channels, indicating what the T71 USB DAC is currently receiving from the host source device.

T71 USB DAC is compatible with traditional stereo earphones and headphones. Despite being designed for surround sound, the T71 still provides an enhanced audio experience when used with conventional stereo headphones.


Useful links:

> Qudelix official store
> Qudelix-T71 NOX case (Dignis store)
> Blog entry with the full T71 features
> User manual (PDF)
> Qudelix forum
> Qudelix support email

 

[rlw6534]

I'm having some trouble wrapping my head around this. With Apple Music when listening to Dolby Atmos tracks with a 2 channel external DAC, doesn't the Atmos still work (if selected in the settings) i.e. Atmos for headphones? Or is the iPhone/iPadMac actually outputting multichannel audio that the DAC can't decode correctly (and channels are missing)?

 

[Merkurio]

I'm having some trouble wrapping my head around this. With Apple Music when listening to Dolby Atmos tracks with a 2 channel external DAC, doesn't the Atmos still work (if selected in the settings) i.e. Atmos for headphones? Or is the iPhone/iPadMac actually outputting multichannel audio that the DAC can't decode correctly (and channels are missing)?

It does, but the Dolby Atmos content automatically downmix to 2 channel from the iPhone/iPad/Mac when you paired a stereo (2 channel) DAC, giving you a much inferior sound result.

On the other hand, when the Dolby Atmos content detects that you are using a DAC with multichannel capabilities (such as the T71 in 7.1 surround mode), then the content is passed entirely to the device and the device itself is responsible for downmixing to stereo in a much more precise and complex way, using the special hardware and proprietary algorithm of Qudelix.

You can do the test by forcing Dolby Atmos and listening with the 2.0 mode in the T71, you will realize that it indeed sounds different from the original stereo mix (worse, in most cases), but when you activate the 7.1 mode you instantly realize how much better it sounds, starting with a better positioning of the channels in space and a greater dynamic range across them, thanks to the audio path that follows the T71 both at hardware and software level.

 

[M3NTAL]

Currently my work DAC for 2-Channel listening. Very, very cool device. I think these things will all eventually be inside at least a headphone and eventually in-ear. The X-MEMS tech. in general seems like it could measure itself against it's reference from the music signal and cancel out anything that isn't wanted in the chain. Audeze's Filter is a planar + a.i. version and so far, everyone says they are shocked I have a nice sounding microphone over VOIP.

 

[SweetCans928]

I can't get Atmos or DTS Headphone:X working at all with the T71 on Windows 11. And it isn't that it should work and doesn't, I'm not able to turn either ON in the first place. Seems unsupported or something. I tried in both 2.0 and 7.1. No big deal, I just wanted to see how it might sound with games. Regardless, I am liking the T71 a ton. Even without the Atmos/HeadphoneX support it's cool seeing that I'm getting all the channels while gaming, and you can hear it in action too(obviously not as pronounced as a surround sound speaker setup). Also, if you go into your sound settings you can hear the different channels by clicking on them, kinda neat.

As a gadget nerd and audiophile, this little device is really ticking all my boxes. What filter is everyone using? I'm just using the default(hybrid fast).

 

[rlw6534]

It does, but the Dolby Atmos content automatically downmix to 2 channel from the iPhone/iPad/Mac when you paired a stereo (2 channel) DAC, giving you a much inferior sound result.

On the other hand, when the Dolby Atmos content detects that you are using a DAC with multichannel capabilities (such as the T71 in 7.1 surround mode), then the content is passed entirely to the device and the device itself is responsible for downmixing to stereo in a much more precise and complex way, using the special hardware and proprietary algorithm of Qudelix.

You can do the test by forcing Dolby Atmos and listening with the 2.0 mode in the T71, you will realize that it indeed sounds different from the original stereo mix (worse, in most cases), but when you activate the 7.1 mode you instantly realize how much better it sounds, starting with a better positioning of the channels in space and a greater dynamic range across them, thanks to the audio path that follows the T71 both at hardware and software level.

I guess my question relates to the quality difference between actual Dolby Atmos for Headphones (which is binaural 360 degrees) and a 7.1 multichannel without height channels (i.e. no x.x.x) being downmixed to 2.0. I obviously don't have a T71 to compare, so I'm curious how it becomes "much better" when it isn't actually decoding atmos (or is it?)... higher bitrate maybe?

 

[bahamot]

Last night I tried with jriver, the only driver that works with 5.1 24 bit 88kHz is directsound. Wasapi limited to 5.1 44.1kHz. Not sure what was wrong.

 

[Merkurio]

As a gadget nerd and audiophile, this little device is really ticking all my boxes. What filter is everyone using? I'm just using the default(hybrid fast).

I’m settled with the default as well (It's not like we're going to perceive sonic differences anyway).

I guess my question relates to the quality difference between actual Dolby Atmos for Headphones (which is binaural 360 degrees) and a 7.1 multichannel without height channels (i.e. no x.x.x) being downmixed to 2.0. I obviously don't have a T71 to compare, so I'm curious how it becomes "much better" when it isn't actually decoding atmos (or is it?)... higher bitrate maybe?

Well, obviously you don’t have the head tracking of the AirPods (which is neat), but pairing it with a nice set of proper EQ’d headphones/IEMs, the surround simulation provided by the T71 it’s quite convincing and enjoyable for Atmos content in Apple Music.

As for actually decoding Atmos, I don’t know, after all Dolby Atmos at its core is multichannel audio as well (proprietary with their own bells and whistles, but multichannel audio nonetheless).

 

[C_Lindbergh]

Are the MEMS mics actually useful? Seems like most people will set far away from the USB dac anyway? Or perhaps there's more features coming with the mics in thought?

 

[Tano]

Are the MEMS mics actually useful? Seems like most people will set far away from the USB dac anyway? Or perhaps there's more features coming with the mics in thought?

I really don't care about the mics, but I guess that they are there in case that you are using the T71 with your phone ,so you can answer your calls if needed. I don't think they are going to implement any features with the mics, but that would be cool, thought.

 

[Tano]

Hi guys. Im having some issues with my T71 battery. Im using it on hybrid mode and the battery has dropped massively 2 times. First time it thought it was a bug, but tonight I was at 56% on my PC. I went to my room and connected it to my phone and it suddenly was at 25%. This is really unfortunate, cause Im really enjoying it and this means that I will have to send it for repair most likely, cause this is not normal for sure.
Just emailed Qudelix to report it.

Anyone experienced a similar issue?

Heres a pic of the battery log. It's obvious that something isn't right.

 

[Merkurio]

Hi guys. Im having some issues with my T71 battery. Im using it on hybrid mode and the battery has dropped massively 2 times. First time it thought it was a bug, but tonight I was at 56% on my PC. I went to my room and connected it to my phone and it suddenly was at 25%. This is really unfortunate, cause Im really enjoying it and this means that I will have to send it for repair most likely, cause this is not normal for sure.
Just emailed Qudelix to report it.

Anyone experienced a similar issue?

Heres a pic of the battery log. It's obvious that something isn't right.

Unfortunately I can't tell because I use it 100% for desktop in VBus mode (I even have charge control disabled, although I read that it was automatically activated if the battery went below 20%, but it has only gone down to 99% after a couple of days of use).

Be that as it may, keep us posted on what happened with your unit!

 

[XTF1]

Hi guys. Im having some issues with my T71 battery. Im using it on hybrid mode and the battery has dropped massively 2 times. First time it thought it was a bug, but tonight I was at 56% on my PC. I went to my room and connected it to my phone and it suddenly was at 25%. This is really unfortunate, cause Im really enjoying it and this means that I will have to send it for repair most likely, cause this is not normal for sure.
Just emailed Qudelix to report it.

Anyone experienced a similar issue?

Heres a pic of the battery log. It's obvious that something isn't right.

It may ‘just’ be a software bug: if you look at the chart, there is an identical vertical jump matching the first drop, and the second drop starts exactly at the same point than the first one, and drops the same value… A dying battery would be much more erratic and inconsistent. So the 25% left may be wrong…

 

[bahamot]

last night I unplugged from the charger it was 75% then this morning I wanted to continue charge it shows 100%. It might be bug in the firmware.

 

[Tano]

It may ‘just’ be a software bug: if you look at the chart, there is an identical vertical jump matching the first drop, and the second drop starts exactly at the same point than the first one, and drops the same value… A dying battery would be much more erratic and inconsistent. So the 25% left may be wrong…

Could be a software bug. But the 2 drops happened at almost the same point cause I used it the same way the last 2 days. I was using it plugged to my pc and then I went to bed and used it with my phone. That's why both match.
Anyways, it's really annoying. I hope it's just a software issue and not a battery problem...