FiiO K11 R2R M79 firmware settings for 1Bit and D2P DSD playback

FiiO K11 R2R DSD Settings: 1Bit vs D2P Explained

2026년 09월 02일, ~에 의해 EMiUZEK Editorial Team, 9 분 읽기 시간

Updated FiiO K11 R2R guide explaining M79, 1Bit versus D2P, DoP transport, native DSD verification and the practical buying relevance.

If your FiiO K11 R2R is running M79 firmware and receiving a real DSD stream over USB, choose 1Bit when you want the unit's new native DSD path; choose D2P when you prefer the established DSD-to-PCM path or need the most predictable compatibility. Neither option is automatically “better,” and the setting does nothing to ordinary PCM playback. The important first step is confirming that your player is actually sending DSD rather than converting it to PCM before it reaches the DAC.

This question has become common because the K11 R2R now exposes two DSD choices that are easy to confuse with bit depth. The display says 1BIT, not “16-bit.” It describes how DSD is decoded inside the unit; it is separate from the K11 R2R's NOS/OS setting for its PCM path.

The short answer: 1Bit vs D2P

Setting	What the K11 R2R does	Best reason to use it
1Bit	Keeps compatible DSD as a 1-bit stream and uses the R2R network as a 24-tap FIR filter.	You have an actual DSD library, a working native-DSD USB chain and want to use the M79 signal path.
D2P	Converts incoming DSD to PCM before the resistor ladder performs multibit conversion.	You want the older, familiar path, easier compatibility or a controlled comparison with PCM processing.

There is no reason to change the DSD option for Spotify, YouTube, games, CDs, FLAC files encoded as PCM or most streaming services. Those sources arrive as PCM, so the DSD menu is not involved.

FiiO K11 R2R showing controls used to select 1Bit DSD mode

First, confirm that M79 firmware is installed

FiiO added 1-bit DSD native decoding to the K11 R2R with M79 firmware. Earlier firmware used the D2P path, so a missing 1BIT menu item usually means the firmware has not been updated. The update is manual rather than an over-the-air installation. Download the K11 R2R M79 package from FiiO's official support page and follow the instructions included with that package. Do not use firmware for the standard K11: it is a different model.

After the update, open the device menu and check the displayed firmware version before changing playback software. Updating firmware creates the capability, but it does not force a computer or streamer to send native DSD.

What actually changes inside the DAC?

According to FiiO's engineering explanation, the same resistor network performs different jobs in the two modes. With PCM—or DSD converted through D2P—the ladder works as a voltage-divider network. With DSD and 1Bit selected, the network is driven as a 24-tap FIR filter. That is a real signal-path difference, not a cosmetic label.

It is still important to separate that fact from listening impressions. Some owners describe 1Bit as smoother or more fluid and D2P as sharper or more explicit. Those descriptions are subjective and can be affected by level, software, filters, recording master and expectation. The feature gives you two valid decoding paths; it does not guarantee one universal sound signature.

Use 1Bit when these conditions are true

You are playing genuine DSD files, not PCM files upsampled only for the comparison.
The source is connected by USB. FiiO's published specifications list DSD support up to DSD256 for USB, while optical and coaxial input specifications are PCM-only.
Your playback software and operating system can send a compatible DSD stream without converting it first.
The K11 R2R display confirms DSD during playback.
You want to evaluate the M79 native-DSD path and are willing to test it without unrelated DSP changes.

If all five are true, 1Bit is the logical starting point. It preserves the intended DSD route inside the updated K11 R2R. That does not mean you must prefer it after listening.

Use D2P when compatibility matters more

D2P remains useful. Choose it if a particular player, operating system or USB configuration is unreliable in native DSD, or if you simply prefer its result. It is also a sensible reference mode because it converts DSD into the multibit PCM-style path used by the ladder.

Software volume control, equalization, crossfeed and room correction often require PCM processing. If your player applies such DSP, it may convert DSD to PCM before transmission. In that case the K11's 1Bit option cannot restore a native DSD stream. Decide what matters more: keeping DSD native, or keeping the processing that improves your system. A useful EQ correction can matter more than preserving a format label.

FiiO K11 R2R connections for comparing D2P and 1Bit DSD playback

How to set up native DSD without guessing

On Windows

Install the current official FiiO USB DAC driver.
Connect the K11 R2R by USB and select USB input.
In a DSD-capable player, select the FiiO ASIO output or another mode explicitly documented by that player for native DSD.
Disable software EQ, volume normalization, crossfeed and resampling for the first test.
Play a known-good DSD64 file and check that the K11 R2R display identifies DSD.
Set the K11 R2R DSD option to 1BIT, then compare D2P with every other setting unchanged.

On macOS, Linux or a network transport

Compatibility depends on both the operating system and player. DoP—DSD over PCM—is a transport packaging method and is not the same as D2P, which means converting DSD to PCM. A player may package DSD as DoP while the DAC still decodes the original DSD payload. Check the player documentation and the K11 display instead of relying on a single software label.

For a streamer, confirm that its USB output supports the required DSD mode. Do not assume that a streamer capable of playing a DSD file can pass native DSD to every USB DAC.

How NOS and OS relate to the DSD menu

NOS and OS answer a different question. On PCM, NOS keeps the incoming sampling rate while OS upsamples before conversion. The DSD menu decides whether incoming DSD uses the new 1-bit route or is converted through D2P. Treat these as separate controls rather than trying to combine “NOS + 1Bit” into a single purity ranking.

For a deeper explanation of the PCM side, read NOS vs OS on an R2R DAC. If the distinction between the formats is still unclear, start with PCM vs DSD.

A fair way to compare 1Bit and D2P

Use the same DSD file, headphones, gain, output and listening level. Change only the DSD setting. Replay a short, familiar passage several times rather than switching albums. If possible, take a break and repeat the test later. Small differences are easy to exaggerate when you know which mode is active.

Do not use an ordinary PCM track for this comparison; both settings should produce the same practical result because there is no incoming DSD for the menu to route. Also avoid comparing a DSP-processed version with an unprocessed version and attributing the difference to the DAC mode.

Troubleshooting: why the display still says PCM

The music is not DSD: FLAC, WAV and ALAC can contain PCM and are not automatically DSD.
The player is converting: look for output settings such as PCM conversion, resampling or DSD-to-PCM.
System audio is in the path: shared-mode mixers commonly output PCM. Use the player's documented exclusive or native route.
The connection is not USB: use USB for the K11 R2R's published DSD capability.
DSP is enabled: EQ and other processing may require conversion to PCM.
Firmware is older than M79: update with the official K11 R2R package before expecting the 1BIT option.

Which setting should you leave on?

For verified native DSD over USB, begin with 1Bit because that is the dedicated path M79 added. If playback is unstable, your software needs PCM-based processing, or you consistently prefer the comparison, D2P is a valid choice. For PCM music, stop worrying about this menu and focus on the NOS/OS choice, gain, headphone matching and level.

The FiiO K11 R2R is currently available from EMiUZEK, and you can browse related models in our DAC & Headphone Amps collection. The useful upgrade in M79 is not that it makes every file sound better; it gives DSD owners a genuine choice between two internal paths.

September 2026 Verification Checklist Before Changing 1Bit or D2P

Current K11 R2R owners still report confusion because three different labels can appear in the same setup: DoP in the player, 1BIT or D2P in the DAC menu, and NOS or OS for PCM. DoP is only a transport wrapper that carries DSD inside a PCM-looking data frame. It does not mean the K11 has converted DSD to PCM. D2P is the internal conversion choice inside the K11 R2R, while NOS and OS belong to the PCM path.

Confirm the device is specifically the K11 R2R, not the standard K11.
Confirm firmware M79 is installed and the menu label reads 1BIT.
Use USB for the first test and play a known DSD64 file with DSP disabled.
Check the K11 display, not only the player interface, to verify DSD reception.
Compare 1BIT and D2P at the same output level, gain and listening passage.

If the display remains on PCM, the source software or operating system is converting before the signal reaches the DAC. Changing the K11 menu cannot reverse that conversion. If the display shows DSD but switching modes produces no meaningful difference, that is also a valid result; the modes provide different processing paths, not a guaranteed audible hierarchy.

Current buying relevance

The M79 update is most valuable to listeners who already own DSD files and want control over the internal decoding path. It does not improve ordinary PCM streams by itself. The FiiO K11 R2R remains active and in stock at EMIUZEK, so the update improves long-term flexibility without changing the basic buying decision: choose it for the compact R2R DAC, headphone outputs and line/preamp use, not solely for a menu label.