Loud hissing sound when playback DSD in DoP mode when using iPhone 17

[MusicFidelity (Guy)]

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Using ARC in iPhone 17 pro max, iOS 26.1, a loud hissing sound when playing back DSD in DoP mode. If DSD is converted to PCM works perfectly. This issue does not happen in iPad Air M3

[Mikael_Ollars]

What DAC are you using (supposedly) to extract the DSD signal?
There is not much point at all in playing DSD to the iPhone/iPad internal audio since you will only load the transfer and/or downsampling unnecessarily.

Show your signal path, both when you consider it working and when not:

[vadim]

Hello @MusicFidelity,

Thank you for reaching out!

To better understand what’s happening with the loud hissing when using DoP on your iPhone 17 Pro Max, could you please share a bit more information?

• What DAC are you using with your iPhone?
• Could you post a screenshot of the Signal Path both when DoP produces the hissing and when PCM conversion works normally?
• Does the issue occur with both local files and streaming services (Qobuz/TIDAL)?
• Have you noticed if the hissing starts immediately or only after a few seconds of playback?
• Most importantly, could you provide the exact timestamp (date + time) of the last occurrence? This will help us review the related diagnostic entries.

Once we have these details, we’ll be able to move forward with deeper analysis.

Thanks in advance!

[MusicFidelity (Guy)]

Hi Vadim,

Here is signal path…

I’m using Khadas Tea Pro USB DAC.

Tea Pro | KhadasTea Pro

There’s no issue on playing back PCM from local storage or Tidal via Nucleus One. However when playing DSD via DoP mode, there’s background hiss with no music. If I convert DSD to PCM it is working fine.

The playback is full length not just starting a few seconds. Time stamp, date 29 Nov at 00:15 to 00:25 hrs Singapore time. Thanks.

[benjamin]

Hi @MusicFidelity,

Thanks for the additional info!

1. Have you tested enabling Exclusive mode with the DAC?
2. Have you tested using a different USB cable?
3. Have you tested using a different audio app on the device other than Roon?

It may also be worth checking Check iOS USB audio routing

Go to:

Settings → Accessibility → Audio/Visual → USB Audio Routing

Turn it ON, then restart the iPhone.

This forces iOS to treat your DAC as primary audio target and reduces resampling glitches.

Thank you!

[MusicFidelity (Guy)]

Thanks Benjamin, the setting force to ‘Speaker’ instead of Auto works.