Observations HiRes - Audio source quality limits for Lucid Stereo System

[Bunnylebowski]

Were you able to confirm playback of USB DD+ MP4 by taking a DD+ MP4 channel identifier and having it play discreet just like this?

Dolby Labs - Channel ID 7.1.4 corners Lfh Rfh Lrh Rrh

Listen to Channel ID 7.1.4 corners Lfh Rfh Lrh Rrh on your streaming service

tidal.com

I think it’s promising it could be played back at all, meaning that the USB input DOES recognize that incoming codec, the question is whether it actually utilizes it correctly, or is just using its own DSP to assign channel output rather that what Dolby encoded.

 

[segbrk]

Were you able to confirm playback of USB DD+ MP4 by taking a DD+ MP4 channel identifier and having it play discreet just like this?

Dolby Labs - Channel ID 7.1.4 corners Lfh Rfh Lrh Rrh

Listen to Channel ID 7.1.4 corners Lfh Rfh Lrh Rrh on your streaming service

tidal.com

I think it’s promising it could be played back at all, meaning that the USB input DOES recognize that incoming codec, the question is whether it actually utilizes it correctly, or is just using its own DSP to assign channel output rather that what Dolby encoded.

Yes, I found a DD+ MP4 Atmos test track like that and did hear all the different channels where they should be.

 

[Bunnylebowski]

Yes, I found a DD+ MP4 Atmos test track like that and did hear all the different channels where they should be.

That’s great! Then I guess the trouble like you said is finding buyable DD+ files to stick onto USB.

 

[DreamTour]

That's exciting, out of cursiosity how big is the file per min of audio? Maybe i'll listen to atmos again because it's not all compressed someday.

 

[DreamTour]

Anyone try this source for Mp4 DD+? Not a lot but i know 2L has published some other high end soundtracks.

Dolby Atmos in MP4 and MKV files

The MP4 video files carries the Dolby Atmos in a 768kbps DD+ container and is user friendly to the Mac OS and iOS devices, including headphone virtualisation. The MKV container holds Dolby Atmos TrueHD in lossless quality and the Auro-3D format. Two audio streams are contained in parallel within...

shop.2l.no

 

[segbrk]

That's exciting, out of cursiosity how big is the file per min of audio? Maybe i'll listen to atmos again because it's not all compressed someday.

The DD+ MP4 format that the car can actually play is compressed. I don't know if Tidal's bitrate is lower or something though.

Anyone try this source for Mp4 DD+? Not a lot but i know 2L has published some other high end soundtracks.

Dolby Atmos in MP4 and MKV files

The MP4 video files carries the Dolby Atmos in a 768kbps DD+ container and is user friendly to the Mac OS and iOS devices, including headphone virtualisation. The MKV container holds Dolby Atmos TrueHD in lossless quality and the Auro-3D format. Two audio streams are contained in parallel within...

shop.2l.no

Yes, their Atmos MP4 files play in the car and they sound fantastic. I checked out their test track as well and confirmed it uses all channels correctly. It's just pretty niche music.

 

[DreamTour]

ok great. Assuming mkv isn’t something the lucid app decodes/ plays?

Patrick

 

[segbrk]

ok great. Assuming mkv isn’t something the lucid app decodes/ plays?

Patrick

Correct. Atmos MKV is the less compressed TrueHD format you get from a BluRay.

For a size reference, their TUVAYHUN file is 3GB and 1:19:45 (1h19m45s) long.

 

[DreamTour]

Correct. Atmos MKV is the less compressed TrueHD format you get from a BluRay.

For a size reference, their TUVAYHUN file is 3GB and 1:19:45 (1h19m45s) long.

Great info thanks, I might buy a track and load it on usb and report back quality difference between a stream and usb.

 

[Bunnylebowski]

Great info thanks, I might buy a track and load it on usb and report back quality difference between a stream and usb.

I confirmed with my audio engineer friend that Dolby True HD files (or other files) cannot be converted into DD+ JOC Atmos files by any consumer methods, you need the Dolby Media Encoder license. Your anmbition of comparing a Dolby True HD version of an .atmos track to the DD+ JOC file would also be accommodated by the Dolby Reference Player (pic attached of what it can do) but you need the DME yearly license to use it and Dolby only gives the licenses to professional applications. Also sadly Dolby is not going to support downloadable lossless MKV files, so while you can get them and play them back over HDMI into a home theater setup equipped to handle it, I don’t think it’s going to happen in the car. Hopefully this saves you guys some time and $ by not spending too much down this rabbit hole. I for one would love to be able to just get access to all Atmos content in one place, I don’t care if it’s all lossy DD+ JOC 7.1.4, it sounds good to my ears in the car, it’s just a bummer when you see there’s plenty of great Atmos music out there beyond what Tidal offers, and no way to hear it in the car until we get native Apple Music support. In my opinion home soundbar systems with satellite discreets also don’t sound as good as the car apart from the dedicated sub unless you’ve got a good room and spend $$$ to get real discreet channels and not just a soundbar with tiny tweeters and up firing ones that mimic actual height channels by reflection. I’ve heard some complain about the price of SSPro upgrade, but you’d pretty much have to drop that $ or much more on a home Atmos setup to get comparable quality, of course with the bonus that you’ll get quality Video with Atmos you can watch.

 

[Bunnylebowski]

I know i am likely in the very small minority of folks who will ever notice this but wanted to share my experimental results in case anyone else wanted to dip into hifi.

As background, I've invested in a full aftermarket build of my Lucid Air's sound system with top of the line components and custom tuning.

Details here for background: https://lucidowners.com/threads/luc...lity-configuration-of-the-factory-audio.4647/

Since I've had this system for a while I started playing around with Tidal, Qobuz, Carplay, and USB audio.

Here are my observations. (Happy to share my experimentation methods if anyone is interested)

1.) The native Tidal App for Lucid I think is bitrate limited even if you set it for Hifi. I think this is a limitation of the bandwidth allocated via the onboard cell modem of the car. Or if not the modem, it's the contracted bitrate that Lucid pays the cell service provider. In my estimation it's capped at 320 kbps. This bitrate limits exists for both stereo and Atmos.

2.) If you use Carplay + Tidal or Qobuz set to stream at CD quality audio (16 bit 44 khz) you will get a noticeable improvement in source quality over the native tidal app.

3.) If you try to stream Hi-Res (24 bit) from either source, it consumes a ton of cell bandwidth, but you don't hear a difference over CD quality stream (This is a carplay limitation which is capped at 16 bit audio, which is strange since wifi has plenty of bandwidth to support such a stream)

3.) A Ripped CD onto USB in FLAC format that's 16 bit 44 Khz sounds more detailed than the Carplay + Tidal or Qobuz stream or equivalent quality. While on paper it's the same, I think Carplay does something \, perhaps downsampling the audio or there's some software limitation over carplay.

4.) My latest experiment: Downloading HiRes (24bit audio + various sampling rates) from Qobuz encoded on FLAC onto a USB shows another jump in detail (although this jump is very subtle compared to 320 kbps -> Cd quality which is more like 720 kbps when compressed)

I suspect those with the stock SSPro system could hear the difference between the native tidal app and carplay + tidal streamed at 16 bit CD quality, but never tested it myself (someone should try it)

Note: Carplay w/ tidal does not support Atmos formats. So using carplay would be for stereo only.

I doubt the stock SSPro system would show any improved detail on 24bit audio over 16 bit audio but once could try and find out.

Anyone else play with Audio sources and can tell the difference?

I believe you’re on to something with Tidal and other streams being capped at 320kbps. The reason why I think you’re right is identical tracks I own in FLAC on USB actually do sound fuller and more detailed when correcting for the level difference between Tidal and USB. I’m not sure why there’s a gain difference between the two either, as compressing a file into something for streaming should not make it quieter. But at least in the Lucid’s case it seems to me the DSP is treating USB input gain differently than streaming for something reason.

 

[DreamTour]

Yeah it’s weird, I’d also like to say that usb 16bit flac sounds better than CarPlay 16bit streams. But that difference is smaller.

 

[Bunnylebowski]

Yeah it’s weird, I’d also like to say that usb 16bit flac sounds better than CarPlay 16bit streams. But that difference is smaller.

Out of curiosity what makes you think streaming is limited to 320kbps? If that was the case I’d think Tidal wouldn’t sound better than Spotify premium but it very much does. Theres a lot of debate about whether one can tell a difference between compression bit rates higher than 320kbps, maybe it’s true that one cannot hear a difference in bit rates, but SOME difference is audible to me so I’m thinking I should attribute that to the quality of the algorithms Spotify and Tidal use respectively for their compressed audio. Compression algorithms selectively delete redundant information, but to my ear Spotify and lesser MP3 compression algorithms seem to delete redundancies that do contribute to the fidelity of the audio.

 

[DreamTour]

Out of curiosity what makes you think streaming is limited to 320kbps? If that was the case I’d think Tidal wouldn’t sound better than Spotify premium but it very much does. Theres a lot of debate about whether one can tell a difference between compression bit rates higher than 320kbps, maybe it’s true that one cannot hear a difference in bit rates, but SOME difference is audible to me so I’m thinking I should attribute that to the quality of the algorithms Spotify and Tidal use respectively for their compressed audio. Compression algorithms selectively delete redundant information, but to my ear Spotify and lesser MP3 compression algorithms seem to delete redundancies that do contribute to the fidelity of the audio.

Just a hunch that Lucid doesn't want to be on the hook to pay the cell carrier for more bandwidth than it needs to. Right now that connectivity is offered "included" for free. Maybe they don't want a huge liability.

 

[Bunnylebowski]

Hmmm I’d think with a huge fleet of cars and to avoid drop outs in Atmos content streaming they wouldn’t go cheap on whatever data speeds they’ve purchased. I was basing my guess on the quality difference noticed between USB and streaming, as in principal FLAC and AAC on USB and streaming should sound the same, but they don’t. And I don’t understand why.

 

[PacificallyLucid]

If anyone want's to test for FLAC multichannel capability you can download test files here: FLAC Test Files. I have a lot of old 5.1 Telarc sampler recordings that have been converted to multichannel FLAC, so I will use the test files, and my converted Telarc recordings to test for multichannel playback when I pick our Lucid Air on Monday. You can convert audio files to DD+ (E-AC3 5.1) using ffmpeg on your computer. You cannot get TrueHD, or Atmos however. In general, ffmpeg can convert from and to most formats. Use your favorite AI model to show you how. To convert from SACD is more involved, but when I was in college I spent the time to do it, so I am excited to try those out as well.

Is everyone just plugging in USB sticks/drives, or is the car able to pull files from your phone and play them. If they play FROM the phone my tests won't work, since phones don't decode to multichannel outputs (AFAIK).

Thanks for all of the posts, I have learned a lot in just an hour.
Cheers.

 

[borski]

Is everyone just plugging in USB sticks/drives, or is the car able to pull files from your phone and play them. If they play FROM the phone my tests won't work, since phones don't decode to multichannel outputs (AFAIK).

USB stick. Drives and phones won't work.

 

[PacificallyLucid]

USB stick. Drives and phones won't work.

Ok. Thanks.

 

[PacificallyLucid]

Testing FLAC 5.1 and 7.1 you get all channels except the LFE (.1). This is definitely an audiophile profile sound system. Very neutral, but present, bass. Would be interesting to see if a low frequency exciter, might be enough to bring in the < 30 hz range. The clarity and presence is very good for a car system. I am happy with it. Better sound than I am able to get out of my Jags.

 

[ccarroz]

I know i am likely in the very small minority of folks who will ever notice this but wanted to share my experimental results in case anyone else wanted to dip into hifi.

As background, I've invested in a full aftermarket build of my Lucid Air's sound system with top of the line components and custom tuning.

Details here for background: https://lucidowners.com/threads/luc...lity-configuration-of-the-factory-audio.4647/

Since I've had this system for a while I started playing around with Tidal, Qobuz, Carplay, and USB audio.

Here are my observations. (Happy to share my experimentation methods if anyone is interested)

1.) The native Tidal App for Lucid I think is bitrate limited even if you set it for Hifi. I think this is a limitation of the bandwidth allocated via the onboard cell modem of the car. Or if not the modem, it's the contracted bitrate that Lucid pays the cell service provider. In my estimation it's capped at 320 kbps. This bitrate limits exists for both stereo and Atmos.

2.) If you use Carplay + Tidal or Qobuz set to stream at CD quality audio (16 bit 44 khz) you will get a noticeable improvement in source quality over the native tidal app.

3.) If you try to stream Hi-Res (24 bit) from either source, it consumes a ton of cell bandwidth, but you don't hear a difference over CD quality stream (This is a carplay limitation which is capped at 16 bit audio, which is strange since wifi has plenty of bandwidth to support such a stream)

3.) A Ripped CD onto USB in FLAC format that's 16 bit 44 Khz sounds more detailed than the Carplay + Tidal or Qobuz stream or equivalent quality. While on paper it's the same, I think Carplay does something \, perhaps downsampling the audio or there's some software limitation over carplay.

4.) My latest experiment: Downloading HiRes (24bit audio + various sampling rates) from Qobuz encoded on FLAC onto a USB shows another jump in detail (although this jump is very subtle compared to 320 kbps -> Cd quality which is more like 720 kbps when compressed)

I suspect those with the stock SSPro system could hear the difference between the native tidal app and carplay + tidal streamed at 16 bit CD quality, but never tested it myself (someone should try it)

Note: Carplay w/ tidal does not support Atmos formats. So using carplay would be for stereo only.

I doubt the stock SSPro system would show any improved detail on 24bit audio over 16 bit audio but once could try and find out.

Anyone else play with Audio sources and can tell the difference?

Tidal has two lossless play options. m4a 32 bits at 44100 and flac at the same. On a track that is under 3 minutes the m4a is 37.1 MB while the flac is 23MB(or at least that is what VLC is showing me, but it also see the hi_res_lossless file as flac, so it might be off since I know its a m4a file). I think what we are getting in the car under high is 320k m4a file. The same track 6.47 mb in size. I'll put them on a USB stick to test out and see if I can hear the difference. I would be surprised if the car can read the m4a lossless file as my decks can not read the file at all. I'll also see if I can rip a Atmos true HD sound file and see how it does with that as well(I doubt I will be able to get this to work though). I wish this car allowed us to edit the seat location or the speaker distance for Atmos music. To my ears it sounds like this was set up to support all seats vs the front, with the net result being the front completely overpowering anything coming out the rear and thus we miss a lot of the mix. I feel like there is a lot of the mix that we do not hear at all vs my set up at home.