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What are head-fi members views on apt-x lossless codec (over bluetooth)?

Discussion in 'Sound Science' started by anakchan, Mar 19, 2012.
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  1. Jabbah
    Yes, the DAC is a digital to analog converter so the data will only go through a DAC once, otherwise it would have to go through an ADC to convert it back to the digital domain. In this case the DAC used will be in the BT headphones or headphone amp with a BT receiver (ie after the BT signal is received). What will happen is that your audio will be transcoded from it's current format (eg MP3 / FLAC) straight to the AptX format for more efficient use of the BT bandwidth. This will probably lead to some loss of quality as AptX lossless is not available for BT. The BT standard does support transmission using the original encoding, but this doesn't seem to be something that manufacturers advertise if they support or not unfortunately.
  2. Class D
    It seems you are looking for a Bluetooth receiver to connect to your audio equipment and you want to have a high fidelity connection with low latency, right?  Does your audio equipment have a  S/PDIF Digital Audio Coax Cable connector for input?  If so, the DAC is already in your audio equipment and you can keep the audio path completely digital using something like the Yamaha YBA-11 Bluetooth Wireless Audio Receiver for Yamaha AV Products.  I use this to connect stereo content to my AV equipment using the Aptx codec in my BT source devices, like a Windowsphone with WP 8.1 denim or a PC with an Aptx BT dongle.  The Yamaha receiver uses an AC adapter for power.  It's a simple solution providing high fidelity BT audio at low latency.  The Yamaha receiver is a fraction of the price of the receivers you are looking at (probably because the onboard DAC is so expensive on the Mass Fidelity and Arcam receivers).                           
  3. ph0n6
    Got the ME Relay and got to say it is pretty neck to neck with my DX50 player, if not somewhat better testing through headphones and streaming FLAC file from my aptx Lumia 1520 with both running through the same amp. It maybe lossy but personally I don't find any detail missing, treble range (which is suppose to be the weakest point of aptx as I have read here https://support.microsoft.com/vi-vn/kb/89879) sounds just fine. Tried it with and iPhone 4 (no aptx) and the sound is worse than Lumia 1520 with aptx, so I guess aptx does work here.
  4. cursor75
          I had been using this AptX Bluetooth receiver in both office and at home. 
          I can't insert any pic so I provide the link to the pic of my office setup (hope the link works).   Btw if you can see the pic, is the one on top.   Lower one is a DAC/headphone amp.
    This BT receiver is not the cheapest in the market.  But it provide both digital and analog output so it is quite easy to swap from one system to another should you happen to need both output sources.
    I do find that there is slight different in audio quality between the analog and digital output of the BT Receiver.  Digital do sound slightly better to me.  Maybe the external DAC do a better job then what the BT receiver does.
    I can't really pick out any difference in Audio Quality when using this BT receiver (in digital output) compare to playing the flac direct from PC to the same DAC or direct from my AV receiver at home.
    The best part is there is no lag in audio when using streaming audio thru this BT receiver.  Cos it kind of annoying when there is a lag in audio when I am watching movies on my tablet or hand phone while audio is stream to other bluetooth speakers that don't support AptX.   Hence my point is AptX do improve a lot on the audio quality. 
    But I must say,  I am not a audiophile nor I had a set of golden ears.  So best is you try on a AptX supported devices that you can get hold on.   :p
  5. tayano
    So has there been any conclusion about BT-AAC? According to Apples Bluetooth guidelines, IOS supports a AAC bitrate up to 264kpbs.
    Does that mean that a AAC 256kbps file will sound as good with BT as wired? 
    The biggest limits with bluetooth was the codec, but with AAC this should be solved?
    I think that AAC 256kpbs is great for portable use.
  6. Rurouni
    Apt-x to my ears still sounds better than AAC over bluetooth. This is based on an uncontrolled test between a mac streaming in Apt-X and an iPhone, to a pair of Sony 1ABTs.
  7. tayano

    What quality was the music file? Lossless?
  8. Rurouni
    Streamed files from spotify as well as some of my ALAC files via iTunes. 
  9. 329161
    Re: the thread title....aptx is NOT lossless. Is it? In any event I don't notice any difference between aptx, AAC or the normal one, over bt with any audio at 256 Kbps or higher. Otherwise there are some "artefacts " that become audible....like you experience with <100 Kbps lossy.
  10. tayano

    So if BT-AAC is as good as AAC, you can hear a difference between ALAC and AAC 256 kpbs? 
    According to apples guildelines, the AAC-codec used for bluetooth is the usual one. Have you checked that it streams in AAC and in a high bitrate using bluetooth explorer?
    So if the sound degradation is not in the codec, where could it else be?
  11. dabotsonline
    aptX HD has just been announced by Qualcomm, available on the CSR8675 Bluetooth SoC, allowing wireless transmission with a 24-bit depth and unknown sample rate (hopefully 192kHz).
    james444 and orion23rigel like this.
  12. watchnerd
    Huh, I find that really surprising...
    I'm not sure how big the Venn diagram intersection is between 'people who like Bluetooth streaming' and 'people who listen to high resolution audio'.
  13. vnmslsrbms
    True.  When I'm doing bluetooth I just want to walk around, not doing serious listening.  Being able to control from another room etc is a plus.  Sound quality if good enough is good enough.  Doesn't need to be hi-res.  
  14. NiHaoMike
    At 2.1Mbps, Bluetooth 2.0 and above have enough bandwidth to stream uncompressed audio at up to 48kHz. (And Bluetooth 3.0 and above has the option of as much as 24Mbps, although I'm not sure how many devices actually implement it.) I actually wonder if that's what Nvidia is doing with their Shield TV remote. It's Bluetooth, but it sounds much better than regular Bluetooth. The chipset inside doesn't support aptx so I think they're using their own proprietary protocol. (They needed to for their Wifi based game controller anyways so it wouldn't be very much extra work.)
  15. watchnerd
    What's the range on Bluetooth 2.0 and 3.0?
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