XMC-1 Optical input loses sound with high-res music

[Kevin]

My Emotiva XMC-1 has always _occasionally_ lost sound when switching between inputs. I tried switching inputs and sound modes, like Reference Stereo, but nothing ever works. Only a full shutdown and restart of the XMC-1 gets the sound working again.

Last week I bought a music steamer. This is connected to an optical input on the XMC-1, using the processor's DAC. I stream high-res music from Tidal and Amazon Music, up to 24bit/192kHz. The problem is now CONSTANT; I lose sound multiple times per day.

The sound always stops when changing songs. It seems to be triggered by the 'bitrate change' between songs, as if the DAC gets 'stuck'. When I check the Info display, it always shows a high bitrate, often 24/192. However I _think_ I've also seen lower rates like 24/96. I'm going to start tracking the exact bitrate change between songs, to confirm my theory.

If I change inputs after losing sound, the processor seems to struggle. The display of the new input name remains on-screen for over 20 seconds. Normally it displays for only a few seconds so this is abnormal. When I check the Info for the new input, the bitrate displayed is _always_ wrong.

For example, when the sounds stops playing from my steamer, I check Info and it shows "192kHz 24bit". When I switch to cable TV, the Info shows "192kHz 20bit". However, the cable TV bitrate is actually only "48kHz 16bit".

This issue does not seem related to similar HDMI sound issues, because it occurs when playing an optical input. The TV is usually on when this occurs, so there is a signal on an HDMI input, but it is only passing through the video, the HDMI audio is not playing.

I could buy an external DAC to use with my streamer, but this is an extra cost. I counted on using Emotiva DAC when I bought it. Plus I occasionally have the same problem on other digital inputs, so an external DAC would only be a partial fix.

This is making the Emotiva useless for playing music. Constantly losing sound is extremely annoying, and rebooting it each time is not a sustainable workaround. If anyone has ideas for troubleshooting this, I welcome them. If I can't fix this problem, I'll have to start looking for a new processor, and that will be costly.

[AudioHTIT]

While there may be some implementations that go higher, I believe most S/PDIF TOSLink (optical) is limited to 24/96. So unless you know that your devices and cables go higher, then it seems probable that your system can’t play 24/192 via TOSLink and that’s when it drops out.

There is a separate problem with the RMC/XMC-2 (and possibly the XMC-1), where the first second or so of each song is clipped (muted) when the bitrate changes. So if you have a playlist of varying bit rates / depths, you’ll hear this a lot. I know of no solution for either problem, other than resampling all files to say 24/96 at the source.

[Kevin]

Dec 26, 2022 21:53:44 GMT -5 AudioHTIT said:

I believe most S/PDIF TOSLink (optical) is limited to 24/96. So unless you know that your devices and cables go higher, then it seems probable that your system can’t play 24/192 via TOSLink and that’s when it drops out.

Thanks for your input. I can play 24/192 music via optical with no problem. I can see the biterate displayed in the Info display, which exactly matches what the steamer says it is sending. This bitrate support is documented in the manual:

Digital Inputs

• 8 – HDMI 1.4b
• 3 – Toslink optical S/PDIF digital audio (up to 24/192)
• 3 – Coax (RCA) electrical S/PDIF digital audio (up to 24/192)

Nor are there any specific songs that the XMC-1 has trouble with. I can play the same song that caused it to lose sound after restarting the unit.

I've had this problem before. I didn't track the sequence, but I think it was likely when streaming Tidal HiFi via a Chromecast HDMI dongle. Non-MQA tops out at 24/96, but I was not even getting that, so this was lower resolution and over HDMI instead of optical.

Dec 26, 2022 21:53:44 GMT -5 AudioHTIT said:

There is a separate problem with the RMC/XMC-2 (and possibly the XMC-1), where the first second or so of each song is clipped (muted) when the bitrate changes. So if you have a playlist of varying bit rates / depths, you’ll hear this a lot. I know of no solution for either problem, other than resampling all files to say 24/96 at the source.

I haven't noticed any song clipping while playing hi-res music, but I'll keep an ear out for that.

I can set my streamer to limit the sample rate, but that's an ugly hack. The point of subscribing to hi-res music is to be able to play it as provided, without down-sampling it. However, this might be an interesting experiment at some point.

I'm going to start tracking the exact sequence of songs when the problem occurs. Then I'll create a playlist of these to see if I can reproduce the problem consistently, or if it occurs randomly. This will help confirm whether it is specific to 24/192 files, and if so, what sequence of bitrate changes triggers it.

[audiosyndrome]

Why are you using an optical input? While it may not make a difference in sound quality, it’s the bottom of the food chain as an input. If you can’t use USB at least try coax.

Russ

[Kevin]

Dec 27, 2022 13:36:49 GMT -5 audiosyndrome said:

Why are you using an optical input? While it may not make a difference in sound quality, it’s the bottom of the food chain as an input. If you can’t use USB at least try coax.

Russ

Optical is the most ubiquitous method for connecting DACs. I use a sturdy 18" Monoprice optical cable, so kinking and durability are not issues. An optical connection avoids potential electrical noise from the streamer that a coaxial cable could transmit in this configuration. I only stream 2-channel PCM so coaxial's higher bandwidth is also not an issue here.

My streamer does not have a USB output. The device's optical output has been independently tested and has a noise level well below audibility, so the signal can't be better in practical terms. Both optical and coax have potential clock-sync issues compared to USB, but this is rarely an issue, plus USB is not an option anyway.

I don't have a suitable digital coax cable to try, but I may get one as a troubleshooting step if this continues. I'll try anything! However it's hard to see how the optical connection would cause the XMC-1 to become 'stuck' in between songs, after playing dozens of 24/192 and 24/96 songs flawlessly.

I have a second, near identical streamer on my secondary system. It connects via an optical cable to an inexpensive Aiyima class-D amp/DAC. This combo streams 24/192 flawlessly. I expect the same from the XMC-1.

[405x5]

Dec 27, 2022 19:23:46 GMT -5 Kevin said:

Dec 27, 2022 13:36:49 GMT -5 audiosyndrome said:

Why are you using an optical input? While it may not make a difference in sound quality, it’s the bottom of the food chain as an input. If you can’t use USB at least try coax.

Russ

Optical is the most ubiquitous method for connecting DACs. I use a sturdy 18" Monoprice optical cable, so kinking and durability are not issues. An optical connection avoids potential electrical noise from the streamer that a coaxial cable could transmit in this configuration. I only stream 2-channel PCM so coaxial's higher bandwidth is also not an issue here.

My streamer does not have a USB output. The device's optical output has been independently tested and has a noise level well below audibility, so the signal can't be better in practical terms. Both optical and coax have potential clock-sync issues compared to USB, but this is rarely an issue, plus USB is not an option anyway.

I don't have a suitable digital coax cable to try, but I may get one as a troubleshooting step if this continues. I'll try anything! However it's hard to see how the optical connection would cause the XMC-1 to become 'stuck' in between songs, after playing dozens of 24/192 and 24/96 songs flawlessly.

I have a second, near identical streamer on my secondary system. It connects via an optical cable to an inexpensive Aiyima class-D amp/DAC. This combo streams 24/192 flawlessly. I expect the same from the XMC-1.

Were I you, I would dump the notion of having “noise” issues with digital coaxial. You don’t know unless you’ve taken it for a test drive. If I were in your shoes I would have run it that way without going optical. Good coaxial’s that meet spec. Are dirt cheap too.