Hello, I was also interested with audio latency on AV receiver. I do not use AV receiver for main video connection, so video latency is not important for me. Throughout two years I've been gathering rough experiment results so I thought I would like to share here:
DENON AVR-1909
Analog in : +8ms
Analog in Direct: +0ms
Optical in (Stereo PCM) : +20ms
Optical in Direct: +2ms
HDMI in : +20ms
HDMI in Direct: +0ms
Surround upmixer (extra latency on top of connection type)
Dolby Pro Logic IIx: +6ms
SONY DA5300ES
Analog in: +15ms
Analog direct: +0ms
Optical in (stereo PCM): +10ms
HDMI in: +10ms
Surround upmixer
Dolby Pro Logic IIx: +6ms
Neural Surround (alternative to PLIIx): +20ms
YAMAHA RX-A3040
Analog in : +40ms
Analog in with Pure Direct : +0ms
Optical in (stereo PCM) : +70ms
HDMI: +20ms
Surround upmixer
Pro Logic IIx (PCM) : +20ms
Dolby Surround Upmixer (PCM) : +35ms
Pro Logic IIx (analog) +8ms
Dolby Surround Upmixer (analog) +20ms
Note:
- I included surround upmixer results as I mainly use it for 5.1 sound upmixed to 7.1.
- All digital connection types are connected with highest sample rate possible (192khz). I found out higher sample rate may improve audio latency, more details later below. Bit depth doesn't affect latency.
I did not include Dolby Digital Live, DTS connect and Dolby Atmos yet as these latency are bad enough I tend to avoid all of it. I am guessing they add around extra 100-150ms.
I can confirm Realtek does not add extra latency and I also made it as baseline.
Onto sound cards, I tried to turn off extra processing as much as I can. Here are the results of sound cards I tested:
Creative Sound Blaster Titanium analog output: +20ms
Creative Sound Blaster Omni analog output: +40ms
I tested Toslink with stereo PCM from Creative SB Titanium with no audio latency. I also recall briefly testing optical for Asus Xonar SE and recorded latency of +10ms. I don't have Omni anymore so I don't have result for optical connection.
I then decided to test some ordinary desktop DACs (not gaming DAC).
Topping D10: USB in, analog output: +0ms
Audioengine D1: USB in, analog output: +0ms
Cambridge Audio Dacmagic Plus: USB in, analog output: +5ms
Note:
- All DACs were tested with highest sample rate possible.
- If available, buffer size were set to lowest possible. Not recommended for normal use as audio may pop and crackle.
So it looked like desktop DACs with USB input are in the clear with latency (but more DACs need further testing to be absolutely sure).
From then I decided to experiment something new just incase I get asked. I decided to find out latency differences when swapping sample rate. This is true for my AV receiver and it is noticeably different. Here is the result.
Yamaha RX-A3040:
HDMI 192khz: +20ms
HDMI 96khz: +40ms
HDMI 48Khz: +50ms
I reconnected my other AV receivers briefly for the same test and did comparison between 48khz and 192khz.
Denon AVR-1909: 3ms difference
Sony DA5300ES: 0ms difference
The latency difference on Denon is very insignificant it is barely any different. On the other hand, Yamaha's latency is significant enough that I had to set at 192khz just to improve audio latency.
Next test, here is the result of swapping speaker layout using HDMI:
YAMAHA RX-A3040:
Stereo: +70ms
Quadraphonic: +70ms
Surround: +20ms
3.1 Surround: +20ms
5.1 Surround: +20ms
7.1 Surround: +20ms
Latency of stereo output actually stumped me. 70ms would become unacceptable for gaming. But I also noticed when comparing from previous result, it is the same latency as Toslink PCM. So I was thinking stereo PCM have more latency than multichannel PCM. Curious, I retested my two other AV receivers.
HDMI Stereo PCM
Denon AVR-1909: +20ms, same result as 5.1/7.1.
Sony DA5300ES: +50ms, 40ms worse than 5.1/7.1.
This got me more confused than ever. My Denon AV receiver is immune to extra latency when comparing stereo and multichannel PCM on HDMI, while Sony & Yamaha slapped off extra noticeable latency. For Sony receiver it is better off using optical for stereo PCM, and my Yamaha receiver is bad either way the best solution is analog connection.
Going back on topic, I am able to come into similar conclusions as yours.
- Multi-channel HDMI latency is low and indeed is the best option for multi channel.
- Multi-channel analog input is a gamble depending on sound card.
- Both Dolby Digital Live and DTS connect via Toslink have horrible latency and should be avoided.
- Dolby Atmos in gaming may be also be as bad as DDL & DTS connect, but I don't have the numbers. If interested I can help test all bitstreaming results when I have spare time.
- Higher sampling rate on PCM may improve audio latency. It did for my Yamaha AV receiver.
- AV receiver latency is too unpredictable overall.