Pops when changing tunes on NADAC 8 + Player

My set up is a system that consists of a NAS and two DACs.

The NAS is a 64 bit system, powered by an Intel i7-4790K Quad-Core 4.0 GHz LGA 1150 88W Desktop Processor (16 GB Memory) mounted on a Asus H97M-E/CSM LGA 1150 motherboard.

The Roon Core resides in the NAS on a 1TB SSD.

All music is stored on a single Seagate ST8000NE0001 hard drive. There are about 40K tracks in this collection. Most of the tracks are wav formatted – I used dBPoweramp to rip them from CDs. I do have a pretty good number of DSD tracks (probably several thousand).

One of the DACS is a Merging Technology NADAC8 + Player. The server is connected to the NADAC8 via two short runs of Wireworld Chroma 8 ethernet cable and a 40 foot run of Audioquest Cinnamon ethernet cable. The signal is routed through two Ubiquity Routers (UniFi 8 POE-150W and UniFi 16 POE-150W). I use an Apple Time Machine router.

There are five devices that are run out of the NADAC8. A multi-channel (Marantz) receiver and two (Atoll MA100) 2-Channel amps are close by. A stereo receiver (McIntosh) and a multichannel pre-amp (Marantz) with separate amps (SPL Performer s800s) are located some distance away (approximately 40 cable feet away). They are connected via Nordost White Lightning RCA cables, joined by two MuxLab RCA/ethernet transformers (and a 40 foot run of Wireworld Chroma8 and AudioQuest Cinnamon ethernet cables).

The second DAC is an USB-connected Chord DAVE located a short distance from the server. Through it, two channel signal is fed to the McIntosh receiver as well as Audeze LCD-X headphones. There are three speaker zones connected to the McIntosh Receiver.

I do not use WiFi, except to operate remote controls (usually an iPhone or an iPad). For the 6 channel systems, I used AudioQuest Cinnamon or Wireworld mid-range cables and wires.

Signals provided by both DACs are interrupted by “pops” while tunes are changing. However, the DAVE is far less consistent and loud.

The pops for the NADAC-8 are quite loud and probably have contributed to speaker damage, especially in the “main system” with the Marantz pre-amp and SPL amps.

I did change the re-synch delay to 500 ms (on the NADAC8) and this did produce some improvement in the loudnesss of the pop sound. It did not seem to impact their frequency,

In an attempt to trouble-shoot this issue myself, I did replace the Netgear routers with the Ubiquity routers several months ago. It did not seem to make much (if any) difference.

Although the pops are very likely to happen when changing to different DSD levels or from PCM, they seem to happen when changing recordings (i.e. “albums”), even when they are from similar sources.

On the NADAC8 and the DAVE, pops are very consistent when changing from a DSD to PCM recordings.

I also have an OPPO 205 and two television sets connected to the Marantz multi-channel receivers. I do not experience any pops when do not use Roon.

I am including a couple of screen shots – one of the Device Setup and one of the Signal Path.

[update 11/9/19 – the problem described below has been resolved, thanks to suggestions received from Noris. The pop problem remains, despite increasing the resynch time to 1000ms}

I don’t know if this is related or not, but I thought I would mention it. I often experience disruption in play back with anything recorded above DSD64, on both DACs and even in stereo.

Here is a couple of screen shots that show this:

I’d appreciate any suggestions you might have.

I have reviewed other reports of similar problems but have not been able to identify any that are similar.

Hi @John_Roberts,

Is there any improvement if you up the Resync Delay setting?

Does this go away if you disable DSP settings?

When I did it for the NADAC (i.e., increased the resynch to 500ms and disabled the DSD settings), the pops did improve significantly, but did not go away.

I then increased the resynch to 1000ms and noticed no further improvement.

This improvement was in the pops but not in the second issue.

[11/9/19 update – the pops are about as bad as they were before, especially when shifting from a DSD or multi-channel recording to a two channel PCM].

On the DAVE, I just tried changing the DSD Playback Strategy to Convert to PCM. I was able to play an entire DSD128 track without the “An audio file is loading slowly. This may indicate a performance or hardware problem.” Instead of “Enhanced” the Signal Path indicates, “High Quality.”

Does this help?

In your third photo shows a processing speed of only 0.3 that is a performance issue.

After I changed the DSD Playback Strategy to “Convert to PCM,” the processing speed went up to 7.2x.

It is looking like I need to stick with this setting, unless you have any other suggestions.

Hi @John_Roberts,

The processing speed does seem quite low and would indicate that your PC is not up to the task of DSD upsampling. You can try toggling Parallelize Sigma-Delta Modulator to see if it helps, but if the processing speed is still under ~1x, you will likley run into issues.

Thanks for the idea.

The DAVE doesn’t seem to have any issue with processing speed, but the NADAC does at least when I am playing multichannel recordings.

With the NADAC, I played around with a number of settings and found that turning off Native DSD and turning on Parallelize Sigma-Delta Modulator managed to get the processing speed to stay above 1.0 (but not much higher).

I have not played it enough to find out if the popping has gone away. However, the cut-outs seem to be gone.

It looks like upgrading the PC is my next project.

Thanks for the help.

Thanks for your suggestions.

The change in settings has worked well, as far as the “cut outs” are concerned.

The pops are still there, despite increasing the re-sych delay to 1000ms. They are especially pronounced when changing from a DSD recording to a PCM one.

Any ideas on how to address this.

Hi @John_Roberts,

Are the pops still evident when you re-sample the content to one specific sample rate or up-sample all the content to DSD using Roon’s DSP Engine?

Hi Noris –

The pops are especially evident when I re-sample from multi-channel DSD to two channel PCM, using Roon’s DSP Engine. I have everything turned off, except for Sample Rate Conversion and Audeze Pre-sets.

By the way, the pops are especially bad when played through speakers.

I have custom settings for Sample Rate Conversion:
44.1kHz to 96 kHz – DSD64
176.48kHz to DSD128 – DSD128
DSD256 to DSD 512 – DSD256

Under Sample Rate Conversion Settings, I have the following turned on:
Sample Rate Conversion Filter: Precise, Linear Phase
Sigma-Delta Modulator: 5th Order
SDM Gain Adjustment: -6DB
Parallelize Sigma-Delta Modulator: On
Native DSD Processing: Off
DSD to PCM Filter: (Recommended) 30 MHZ low pass filter
DSD to PCM Gain is 0.0DB

I have also set the resynch delay to 8000ms

Thank-you for any suggestions you might have.

Hi @John_Roberts,

It looks like you are still resampling your content to DSD rates here, I would start off with a less-demanding test.

Can you please try disabling your Audeze presets and try converting all your content (including DSD) to 192kHz and try outputting to the DAVE zone? Does the music play as expected then without pops? If not, does 44.1kHz?

With this test, I am trying to determine if all sample rates are affected and if the presets are factoring into the equation here.

This is quite a high resync and I’m not sure it’s the root cause or if it’s helping too much. I would try setting the resync back to 1000ms while we investigate the above.

I did as you requested with the Dave 2 channel DAC. At 192kHz, there is no issue. I switched between music recorded at multi-channel DSD128 and 2 channel 24/48 recordings, even mid playing. No pops; no issues!

This was all done with re-synch at 1000ms and with the Audeze presets turned off.

Also tested at 352.8Kz, 769KHz, DSD64, DSD128, DSD256 and DSD512 – all with the same results (no issues).

All tests were done until this point was with Parallelize Sigma-Delta Modulator turned on and Enable Native DSD Processing turned off.

Next, I turned off the Parrallize Sigma-Delta Modulator and turned on the Enable Native DSD Processing. When playing 24/48 music (at DSD512 setting), it played without a hitch (the processing speed was1.1x). When playing multi-channel DSD128 6ch music, an error message appeared (an audio file is loading slowly. This may indicate a performance or hardware problem. (processing speed was .8x)

Next, I lowered the setting to DSD 256, while keeping the Parrallize Sigma-Delta Modulator turned off and the Enable Native DSD turned on. There were no issues. The processing speed was 1.3x.

Do you want me to try similar testing with the NADAC8?

[November 14 UPDATE:]

I went ahead and did the same testing with the NADAC 8 Channel DAC. I kept Parallelize Sigma-Delta Modulator turned on and Enable Native DSD Processing turned off.

There were no issues from 24/48 through DSD128. When I increased the setting to DSD256, the popping returned.

Recordings made in DSD256 play without difficulty as DSD256.

Do you have any other tests or suggestions?

It sounds like the computer needs to be a bit beefier to do what you want. Try an i9-9900K.

Thanks for the comment. This has been gradually becoming clear to me throughout this process. In fact, going through this has made me more comfortable with making such an investment.

It is also becoming apparent that with some adjustments (such as what I have been doing through this process), I can do some critical listening within the parameters allowed by my equipment. I plan to “play this out” and see where it takes me.

Do you know of any music servers with an i9-9900K built in?

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Not that I know of at this point you are getting into a specific built computer. You might be able to use a lesser CPU. Clearly you are at x.08. You would probably be stable if you were at 1.3x or higher.

Multi-channel + DSD processing is very intensive. Heck, depending on the filters applied just a straight upsampling to stereo DSD512 can be problematic. If you are interesting in DSD 512, you should check out HQPlayer, before going much further. HQPlayer can off-load the part of the calculations onto CUDA based GPU’s which can offset the need for a CPU upgrade. As well as allow for an amazing amount of filter options.

There is a forum here for HQPlayer. And I know there are threads discussing Hardware requirements for various filters and DSD512. As well as, which filters sound the best, obviously personal taste.

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[UPDATE on November 14 UPDATE]

Assuming (always a dangerous thing to do)that playback has been “solved,” I put on Roon Radio to enjoy my music.

The pop is back.

It seems to happen whenever there is a change in in bit rate or type of DSD playback. I did a little more testing and found that it occurs even when I shut off Sample Rate Conversion as well as the “send stereo/mono content as 7:1” button (it doesn’t seem to do anything, anyway). With all of that shut off, it still occurs, especially when Roon Radio changes from one sample rate to another (from original source). It doesn’t seem to matter whether the sample rate goes up or down.

The pop doesn’t seem to happen when Roon is playing sequential tracks from the same album. This has also been the case since the popping began.

I also notice some pops when I try to reduce the volume using the slider. It doesn’t seem to matter whether I use the “-” button or the slider. It still pops and often actually increases the volume, temporarily, while I am trying to lower it.

Hi @John_Roberts,

Just to clarify, the pops are only happening on the NADAC 8 now? The Chord DAVE is working as expected? If the issue is only occurring on the NADAC 8, have you by any chance reached out to NADAC regarding your report?

The Chord DAVE is working pretty well. I want to keep playing it to see if things stay good.

I did reach out to NADAC this morning. I spoke with the Distributor and ended up emailing Merging Technology this morning. They are in Europe (and I am not), so I may not hear from them till Monday.

Is there anything in particular you want me to tell them, other than what we have already tried?

Is there anything else we can try in Roon?

Hi @John_Roberts,

You can feel free to include a link to this thread, but I would be interested to know what NADAC replies with regarding this issue when you hear back.