TOPIC:

SHD Studio 1.15 Firmware 1.32   Setup - AVR to AES XLR input. Four outputs from AES XLRs to DAC to four subwoofers.
Random pops from all subs, like frequent short bursts of automatic weapon or popcorn popping.
If source is or was 44.1KHz, popping occurs. If any other sample rate, no popping.
Popping from different outputs is not at the same time.
Popping occurs even if no filters loaded.
Popping occurs even if no connection to computer.
Once started, popping persists even if all Selectable Input Sources are disabled.
Once started, popping persists even if input AES XLR is removed.
Goes away when outputs are muted or not assigned or with Master Mute. 
Goes away if Master is -67 dB  or lower. At -66dB popping occurs.
Goes away on any output if individual output gain is -67 dB  or lower.
Goes away if Channel is -37 dB  or lower on Routing page. At -36dB popping occurs.
Goes away when input is switched to LAN, even with no LAN cable attached. 
Not detected by the comp/limiter at any settings, even with threshold at -90.

@ jamesren

Something else is going on here.. We assume that you're AES-EBU (i.e. Digital out from your AVR)? 
The SHD Studio is AES-EBU = DIgital Stereo device. 

What AVR are you using that output AES-EBU ? It's quite rare to get a SUB out as AES_EBU... Typically they are analog out.. 

If that's what you're doing here, that would explain maybe the issue here? 

As usual, always best to start a support ticket to talk to our team. We'll be here to help! 

devteam

I'm familiar with AES/EBU protocol. AVR is Trinnov Altitude 32, AES/EBU output drives SHD Studio XLR input. One channel (only) is routed to four outputs of SHD Studio (2 x AES/EBU XLRs) to four channels of an 8 channel DAC, a Dangerous Music Convert 8. Cable is Belden 1800B 110 ohm Digital Audio Cable. 

Popping only occurs when SHD Studio receives an input with a sample rate of 44.1kHz. Popping is reduced when music is playing, but if music is paused, popping is quite severe. Even if AES input connector is removed, popping continues. There is no problem when input sample rate is 48kHz or higher.

I can work around this by converting any 44.1k inputs to 48k in the Trinnov. 

I have opened a support ticket.

Problem Solved!
I didn't understand that SHD Studio output clock rate is fixed at 96kHz. I had mixed sample rates going into the multi channel DAC.

Thanks for your help.

-James

Glad to hear that you're all set James!