0

LG Sound Sync - What to buy?

xomex

February 13, 2023 21:37

None

Follow

I am looking to get LG Sound Sync to work with my current speaker setup.

 

-- Status Quo --

My current Setup is as follows:

(PC --HDMI->) LG TV [1] --Toslink-> Cheap Toslink DAC [2] --3.5mm to cinch-> AMP [3] --copper cable-> Speakers [4]

The problem is that I can only control the volume in the following ways:

- On the PC in Windows itself - only if I am using it, not applicable for smart TV content nor Console

- As the AMP supports Bluetooth, I can cut out the DAC and control it that way, but that has a delay

- On the AMP, but I have to get up for that, which is what I want to optimize

When searching for LG Sound Sync I stubmled upon the hifiberry DSP repo [5] where the protocol was reverse engineered. Other than that I did not find any statements about the support of LG Sound Sync. ([7] has problems with it)

I still hope that I could replace my DAC with a DAC based on hifiberry. However, since I am not into Audio equipment that much I am a bit overwhelmed by the amount of different products and which to choose. (I already have a Pi 1 and 4 available.)

 

-- My Thoughts + Questions --

If I understand it correctly, I need DAC+DSP to modify the signal such that it is not as loud and then be analog. However, I feel like a DAC should also suffice, as it can read the toslink data and then change the analog output accordingly without having to modify the digital signal itself. (Why) Do I need a DSP?

Based on [6] the only two boards supporting digital input are "Digi+ I/O" and "DAC+ DSP", recommending the latter. Redaing its spec sheet, the input is "only" upt o 96 kHz while the output is at 192 kHz. Should I worry about some signal degredation there? My current cheap DAC supports 192 kHz, so in terms of quality this sounds like a downgrade. Also: should I worry about compatibility?

I also stubmled upon the Beocreate 4 channel AMP. This seems to support 192 kHz sampling. This would also replace my current AMP. What are the other upsides/downsides compared to the DAC+ DSP?

 

-- Overall Questions --

With which HiFi Berry devices does LG Sound Sync work? If it doesen't work out of the box, can I still use the HW to analyze the signal and mess with the software to understand the encoded volume?

What setup would you recommend?

Thanks in advance :)

 

-- Links --

[1] 43UN71006LB https://www.lg.com/de/tv/lg-43un71006lb

[2] https://www.amazon.de/gp/product/B07C76K79J/

[3] douk m1 pro, cf https://www.ebay.de/itm/266098426452

[4] https://www.bose.de/de_de/support/products/bose_home_theater_support/bose_2_speaker_home_theater_support/am5_series3.html

[5] https://github.com/hifiberry/hifiberry-dsp/blob/master/doc/reverse-engineering-lg.md

[6] https://www.hifiberry.com/docs/hardware/comparison-of-hifiberry-cards-for-audio-recording/

[7] https://support.hifiberry.com/hc/en-us/community/posts/6072414429969

• Facebook
• Twitter
• LinkedIn

8 comments

• 0
  
  HiFiBerry team February 14, 2023 08:41

  LG Soundsync requires a DSP as the software uses the DSP to read the necessary meta data. However, there is no guarantee that this will work with a specific TV. It is a reverse-engineered software. The implementation might not work with all LG TV models.
  If it doesn't work for you, you can modify the software if you analyze the metadata from your TV. 

  TOSLink is limited to 96kHz on all our DSP boards. That's no problem at all with TVs as TV sound uses maximal 48kHz.

• 0
  
  xomex February 23, 2023 23:29

  Thanks. Ordered one and got it working after some fiddling (exploring the codebase, understanding sigma studio, getting the cutoff volume more sensitive).

  Programmed the DSP to do it on its own instead of having the pi extract the data and write the volume back. Would you be interested in including this in example profiles?

  Where do I find information on which input/output/gpio numbers correspond to what on the board?
  Seemingly asrcin 1,2 is the pi. 14,15 is toslink in. Outputs I don't know. GPIO 7 is the green led. GPIO 13 doesen't seem to do anything (labelled as amp mute in dsp program).

• 0
  
  HiFiBerry team February 24, 2023 05:34

  It would definitely be interesting. We're happy to have a look and see if we might integrate this into future DSP profiles.
  
  ASRC output are no GPIOs, but just sample rate converters.  You need to check what a specific ASRC is connected to (it can be very different things).
  GPIO7/13 controls the MUTE of the DAC (on some boards with an amplifier ist controls the MUTE of the amplifier).

• 0
  
  xomex March 04, 2023 14:29

  Should I open an issue or PR, or some completely different channel?

  You need to check what a specific ASRC is connected to

  Is there documentation on this, or is it trial and error.

  As for the GPIOs, is there documentation on the remaining IO pins?

• 0
  
  HiFiBerry team March 04, 2023 14:48

  You can create PR with your project file on Github. That's probably the easiest way. About the ASRC: You can just look up the ASRC settings in SigmaStudio. ASRCs can be mapped to GPIOs, but also other inputs and outputs of the DSP. You can see this in the ASRC configuration in SigmaStudio. Different profiles can use different ASRC channels for the same function. 

• 0
  
  xomex March 04, 2023 16:03

  Ah, that clarifies asrc (mostly).

  The ADAU145x have 14 GPIO pins. How are these connected on the DAC+ DSP board?

  Further, how are the GPIO pins of the pi used? (Is there a doc saying which is used for what?)

• 0
  
  HiFiBerry team March 06, 2023 08:20

  You can find the GPIOs used by a specific board here:
  https://www.hifiberry.com/docs/hardware/gpio-usage-of-hifiberry-boards/
  
  Only the audio interface is connected to the GPIOs. No other DSP GPIOs are routed to the Pi.

• 0
  
  xomex March 06, 2023 17:04

  Missed that doc. Are the DSP GPIOs routed somewhere else? Would be nice if they could be used in a profile as well (e.g. volume knob, toggling some setting, ...) without having to use the pi for that.