- Apr 10, 2021
No idea, but frequency extremities sound rolled off, everything sounds flat and washed out. I use a Pi streaming into the same set up (via USB) and the audio quality difference is night and day. Which, when added to the fact everything via TV shows at 48hz on the DAC, makes me think audio is being meddled with by the TV, and for the worse.What makes you think the internal DAC is crappy - from a perspective of resampling (if this is happening at all), rather than analogue conversion?
I set the volume to 100, but as soon as I use optical out rather than TV speaker out the volume function no longer exists.It might be most likely in your case that the output volume is too low, do you have a way of determining how loud the signal is coming into the Topping?
As far as I know, optical SPDIF is always a full scale digital out absent of volume control. When you constrain the SPDIF to always be pcm, it will pass through any received pcm signal, and convert all others to two channel pcm.
I have a Panasonic, a Sony, a Samsung and an lg. None of them permit volume control on optical SPDIF. I didn’t think that was possible. I enter a topping DAC in preamp mode driving a power amp and it sounds great.
Cheers @litemotiv. Obvious now you mention it.Optical Toslink out is either PCM stereo or a Dolby bit stream, logically the receiver of the signal neads to by capable of decoding such. Auto means that it streams it as it is. How good down conversion to PCM stereo is implemented on the TV side depends of implementation and also what it does about DSP and conversion regarding stereo PCM signal and output.
I have a bit newer GX 8xx and I don't find optical PCM 48KHz out (to my Yamaha) washed out. You can actually lower the PCM line out down in dB on TV and make sure that you disable what ever of processing you can on the TV end. I find TV audio sources (individually from broadcaster to broadcaster) problematic as much as they can be. Some using normalisation and some don't and cetera.
I've disabled everything I can (bass boost, EQ, normalisation etc etc). PCM level adjustment makes no difference either.I have a bit newer GX 8xx and I don't find optical PCM 48KHz out (to my Yamaha) washed out. You can actually lower the PCM line out down in dB on TV and make sure that you disable what ever of processing you can on the TV end. I find TV audio sources (individually from broadcaster to broadcaster) problematic as much as they can be. Some using normalisation and some don't and cetera.
The above hints at the D90 being the issue? Perhaps the optical input has limitations
Alas I don't have anything else that would help. Ah well, I'll file my TV Output Signal alongside Nessie and Bigfoot and move on.It's difficult to say at this stage, but if you would have another device to test with that could perhaps give some insight into what is going on.
In theory it could be a bug in the TV, if they send an attenuated signal over optical to the Topping, or if they use the gain/attenuation signal that is set for the speaker output and send that along with the optical signal.
Some further testing with other devices could provide some more details...
HDMI carries a digital signal, not an analogue one. It is not possible for the DAC in your TV to be used, and then transfer analogue to your AVR via HDMI.
So the DAC in your AVR is the one being used. It is possible some resampling goes on in your TV, but that is done digitally, and I am pretty certain you will be unable to hear any quality impacts coming from that - unless it is a broken implementation.
The fundamental question - are you happy with the sound? If so, then you don't really need to worry further.
So its settled? my TV is good enough to stream connected through HDMI Arc?
Thankyouu!!It seems to be your best option. However with ARC there are different implementations and some might still downsample the audio to PCM before sending it to your AVR. Since your TV is quite new there is a good chance it supports HDMI 2.1 with eARC, this will allow bit-precise playback for all formats and bitrates. If your TV does not support eARC it may downsample some streams before sending it through: