If I connect my Pi to a home A/V receiver via HDMI, how would audio quality compare to coming out of a DAC?
Came to look for the same answer, would a dac with a usb input or a dac with a hdmi input or a plug in dac like hifiberry sound best? I mainly listen to CDâs and flacs copied to a HD and use volumio on a Pi2. Also I have a higher end system.
Cheers
Usb DAC makes the cpu load higher and takes up a USB port. But they are commonly available in a wide price range. From cheap with low quality and with very high quality for an incredible amount of money.
I2C DAC doesnât use a USB port, are more and more available. Fit perfectly on your device if when there made for it.is compact. And donât stress the cpu as usb. Price quality level is good on basically all the versionâs Iâve seen on this forum.
HDMI, doesnât use a USB port and doesnât do the CPU load like usb does. You would use the DAC in your amplifier. The sound should be rather the same as your other devices connected.
Ampâs like that dont come cheap but you would probably already have one that you want to use.
HDMI would have my preference if you already have the HDMI amplifier and want to connect to it. You donât have to buy anything more and the sound should have the same characteristics as your other devices.
But I donât have such an amplifier so I use a I2C DAC. Specifically the Iqaudio pidac+ that hit the price quality sweetspot for me. That is on paper, havenât compared the audio my self. Taking in mind the Ir and potentiometer headers and more premium look of the pcb 
Tl;Dr;
It all comes down to the quality you want and the money you got. (or had after purchase 
)
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Iâm building a system (receiver and speakers, anyway) from scratch. Iâm not concerned about surround sound since I donât watch many movies, but I am very concerned about quality of music. So I am considering a stereo receiver rather than an A/V receiver. (Donât need the extra channels.) I currently use my TV to switch between Chromecast and BluRay; I would continue to do that if I get a stereo receiver. The audio is output on the TVâs RCA line out jacks. Would The same not be the case if I used an HDMI input on the TV for the Raspberry Pi? If I did get an A/V receiver that has HDMI inputs, would HDMI on the receiver only handle video if the receiver doesnât have a DAC?
I would not use my TV to switch audio, use a dac or receiver. I am actually considering this http://www.essenceelectrostatic.com/product/hdacc/ as my pre-amp/dac, right now I use an Emotiva UMC-1 for the switching and dac duties. I just donât find it up to par with newer dacs.
TV, although it may do the job of switching, it wasnât meant and itâs probably pretty noisy. I would get either a good dac/pre-amp combo like the one Iâm considering or a good 2-channel receiver with an external dac.
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It is a bit odd phrased question because you are mixing signal transport and Digital/Analog Conversion in one question.
But I understand your goal 
When looking at both parts (DAC and transport), the quality of the DAC is the most important one and then the way you transport which type of signal.
Looking for the best audio quality is finding the best part in the chain to do your D/A Conversion.
If you have an A/V receiver, it most likely has an onboard DAC. You could use that one and use a good signal transport mechanism to transport the digital signal. HDMI could be an option (but there are still some limitations like max 48khz, 2 channels. Look for more info on HDMI and the work in progress to update HDMI to 192khz, 8 channels).
Also a good alternative to transport a digital signal from the Pi to an A/V Receiver (or independant DAC) is using something like the Hifiberry Digi+ which creates an SPDIF signal from the I2S GPIO and outputs to COAX or TOSLINK (Optical) depending on the available input of the receiving device. COAX is prefered over TOSLINK as TOSLINK has also some limitations (more info can be found also on this forum).
The alternative is to use one of the many I2S DACâs that are available and transport the analog signals to the amplifier (use good cables as analog signal are more sensative to âradationâ from surrounding cables and devices).
My personal pref in your case? Get something like the Hifiberry Digi+ and feed the A/V receiver that way. This leaves you with the option to improve the quality later on if you want by putting a better (independant) DAC between the Pi+Hifiberry and the Receiver.
As I understand it, each transport has their limitations/tradeoffs (Iâm open to feedback on this list. Iâm still learning here):
HDMI:
Pros:
- Doesnât take much CPU time (handled by VideoCore GPU)
- Lots of used HDMI receivers on the market that can handle multichannel DAC/AMP duties for less than $100 total
Cons:
- HDMI tends to be high jitter (avsforum.com/forum/173-2-cha ⌠eiver.html)
- HDMI passes through the black box VideoCore subsystem before streaming out. May not be bitperfect?
- On RPi, HDMI is currently limited to 2ch 48kHz. Thereâs a pull request waiting in the raspian github to change this to 8ch 192kHz.: github.com/raspberrypi/linux/pull/1257
USB
Pros:
- Only option for multichannel output right now
- Asynchronous USB DACs can ensure low jitter
- Wide range of price, functionality and availability
Cons:
- USB output eats CPU. RPI1 can run out of CPU headroom for hi-res multichannel output
- USB shares resources with ethernet, so if youâre running heavy network operations, theyâll run out of resources
I2C
Pros:
- Shortest signal path. (Discussed at length here: sound-quality-limitations-raspberry-i2s-dacs-t2391.html)
- Guaranteed âbit-perfectâ to DAC
- Does not take significant CPU resources
Cons:
- High jitter (due to cheap RPi clock), unless you can run RPI DAC clock as master
- Output limited to only 2 channels PCM
Myself, Iâm waiting for the multichannel HDMI to come through. Iâm not too worried about jitter at my level, and I like keeping DAC/AMP costs down by using an older high-quality HDMI receiver, since I need 4-6 channels of amplification for my active speaker work.
For what itâs worth, I have two Pi B streamers, one running Volumio out to the stereo and one running OSMC for video streaming. Both use HiFiBerry Digi cards to provide output , OSMC via optical and Volumio via coax. The audio side runs stereo because thatâs pretty much all there is out there in terms of recordings, and so the coax feeds out to a Musical Fidelity V-DAC II/V-PSU II combo, thence to the AV receiver. The video Pi throws multi-channel sound out to the AV side of the receiver, again via a Digi and an optical link, albeit an original Digi running on a Pi B. Still amazing to test it with Star Wars and get the blue light come on the receiver for 5.1 sound and hear the Star Destroyer go overhead.
This way, the Pi only has to arrange for the file (video or audio) to be presented to the I2S interface as I desire it, it doesnât have to do anything more and so doesnât expose the file to any Pi-created glitches. Equally, it means that each bit of the transmission path from file to eye/ear can be optimised according to my resources or what I feel like doing. An all-in-one solution has its pluses, thatâs for sure but I felt that this way I wouldnât be hitting the things that youâre asking about.