LufiaASIO — High Performance ASIO for Audio & Acoustic

[Lufia]

Hi everyone. I am Aspirin, the developer of LufiaASIO. Version 1.2.8 Alpha is my first public preview release.

LufiaASIO presents one ASIO device to a Windows host, while allowing the actual input and output backends to be selected independently. The primary use case is an audio or acoustic measurement bench where the preferred ADC, DAC, host application, and driver do not naturally fit inside one conventional ASIO device.

Official site: https://lufiaasio.github.io/

LufiaASIO 1.2.8 Alpha control panel.​

What problem is it intended to solve?​

Many measurement applications expect one ASIO driver to own both input and output. That can be restrictive when, for example:

• the ADC and DAC use different native ASIO drivers;
• an ASIO-only host needs to reach a Windows WASAPI endpoint;
• capture should use native ASIO while playback uses WASAPI Exclusive or WDM-KS;
• a legacy Windows endpoint must be combined with a modern measurement interface; or
• the host needs a very large buffer for a long FFT or sustained acquisition, while the downstream device uses a different native packet size.

LufiaASIO keeps input and output independent and reports an unsupported combination instead of silently changing to another API.

Five input backends × five output backends​

Input ↓ / Output →	WASAPI	MME	DirectSound	WDM-KS	Native ASIO
WASAPI	✓	✓	✓	✓	✓
MME	✓	✓	✓	✓	✓
DirectSound	✓	✓	✓	✓	✓
WDM-KS	✓	✓	✓	✓	✓
Native ASIO	✓	✓	✓	✓	✓

WASAPI provides Auto, Exclusive, and Shared choices. Each side has its own mode, device, and channel-count selection. The matrix describes routability; it does not mean that all 25 backend pairings are bit-perfect.

Other design points include:

• Native-ASIO aggregation: one ASIO device in the host can capture through one vendor ASIO driver and play through another, if both vendor drivers permit simultaneous access.
• Native WASAPI Exclusive format probing: the endpoint is queried directly rather than being limited to the sample-rate list displayed by the Windows Sound control panel.
• Host buffers from 512 to 1,048,576 frames: intended to cover responsive operation as well as long FFT and recording workloads.
• Observable diagnostics: discontinuity, FIFO underflow/overflow, callback, frame, and maximum-watermark counters are visible in the control panel.
• Stable device recall: profiles follow the backend's native device ID rather than relying only on a possibly duplicated or reordered display name.

Bit-perfect and ultra-high-rate claims, with the important qualifiers​

• Compatible native-integer WASAPI Exclusive and native ASIO routes can remain bit-perfect when all processing and format conversion are disabled.
• Some native-integer WDM-KS paths can also be bit-perfect when the device format and requested rate match.
• MME, DirectSound, WASAPI Shared, floating-point conversion, Windows format conversion, THD Compensation, and Notch are not advertised as bit-perfect.
• LufiaASIO can expose WASAPI Exclusive rates up to 1,536 kHz / PCM32 only when the connected endpoint and its driver actually accept that format. Unsupported rates are not simulated or resampled into existence.
• My current public stress-test report demonstrates exact full-32-bit loopback at 768 kHz on the stated test hardware. It does not claim a measured 1,536 kHz result.

Higher sample rate is useful here mainly for wider observable bandwidth, shorter acquisition time at a fixed FFT length, and finer time-domain sample spacing. It does not by itself improve converter linearity, amplitude accuracy, or Hz-per-bin resolution.

Public digital-loopback test scope​

The published test used a 2-input × 2-output Brüel & Kjær Sound & Vibration physical digital audio loopback bridge developed on XMOS. It covered 32-bit and 64-bit hosts, format compatibility, exact sample comparison, a six-size host-buffer sweep, and representative sustained operation.

Route / test	Coverage	Reported result
WASAPI Exclusive	768 kHz, full-width 32-bit pseudorandom data; 512 through 1,048,576 host frames	Exact complete-sample loopback passed at all six buffer sizes
Native ASIO	768 kHz, same six-size buffer sweep	Exact complete-sample loopback passed at all six buffer sizes
WDM-KS	Eight device-exposed rates from 44.1 through 384 kHz	Exact full-32-bit loopback passed at every exposed rate
Low-buffer sustained runs	Native ASIO and WASAPI Exclusive: 120 s at 768 kHz / 512 frames; WDM-KS and MME: 60 s at 384 kHz / 512 frames	Zero reported discontinuities, underflows, and overflows in the listed cases
Processing matrix	WASAPI Exclusive/native-ASIO input-output combinations; bypass, THD Compensation, Fixed Notch, and Adaptive Notch; x86 and x64 hosts	32/32 streams passed

Full report: LufiaASIO Public Stress Test Report — July 23, 2026

These results describe that specific digital-loopback system. They are not a calibration certificate, a regulatory test, or a guaranteed specification for unrelated hardware.

Example measurement workflows​

In APx500, LufiaASIO can act as the ASIO connector while either direction is routed to native ASIO, WASAPI Exclusive, or WDM-KS. In REW, it can combine the input of one interface with the output of another without abandoning the ASIO host path. It can also prevent REW from becoming unresponsive when audio devices are frequently disconnected and reconnected.

APx500 — 768 kHz digital-loopback example

Room EQ Wizard — 768 kHz digital-loopback example

The displayed results belong to the pictured Brüel & Kjær/XMOS digital-loopback setup and are not guaranteed specifications for other hardware.

Optional measurement processing — and why it must be disclosed​

LufiaASIO also contains per-channel polynomial THD Compensation and an Adaptive/Fixed digital Notch on eligible native ASIO and WASAPI Exclusive routes.

• THD Compensation is intended for a calibrated chain with coefficients tied to the device, channel, level, load, and setup.
• Adaptive/Fixed Notch suppresses the captured fundamental so residual harmonics and noise are easier to inspect.
• Both tools intentionally change sample values. They must be disabled for bit-perfect transport tests, and any result obtained with them must identify the processing as part of the measurement method.
• A processed result should always be compared with a clean, unprocessed baseline.

Spoiler: THD Compensation and Notch screenshots

Per-channel THD Compensation

Adaptive/Fixed digital Notch

Current Alpha boundaries​

• Windows 10/11 and PCM only.
• Two devices showing the same nominal sample rate do not necessarily share one physical clock. LufiaASIO deliberately avoids adaptive sample-rate conversion, so independently clocked devices can drift until a FIFO underflow or overflow occurs. Long synchronized measurements should use a confirmed shared hardware clock.
• A vendor ASIO driver may reject a second instance or simultaneous access through another API.
• Native ASIO channel selection currently uses the first enabled channels rather than an arbitrary channel-routing matrix.
• MME and DirectSound are compatibility paths and may involve Windows conversion.
• Version 1.2.8 Alpha must be independently checked against a trusted reference before compliance, certification, or production pass/fail work.

Availability and documentation​

• Official site: https://lufiaasio.github.io/
• GitHub Releases: https://github.com/aspirinkisalol/LufiaASIO-Release/releases
• README and setup notes: https://github.com/aspirinkisalol/LufiaASIO-Release
• Packages: the x64 MSI registers both x64 and x86 ASIO components on 64-bit Windows; a separate x86 MSI is provided for 32-bit Windows.
• Integrity verification: SHA-256 files are published alongside both installers.

Feedback I would find useful​

I would especially appreciate reproducible reports from APx, REW, SoundCheck, DAWs, and other ASIO hosts. For a useful Alpha report, please include:

• LufiaASIO and Windows versions;
• host application and whether it is 32-bit or 64-bit;
• input/output backend, mode, device, sample rate, channel count, and host buffer;
• whether THD Compensation or Notch was enabled;
• FIFO/discontinuity diagnostics and exact error text; and
• reproduction steps, plus an unprocessed reference result where measurement accuracy is involved.

Critical questions and reproducible counterexamples are welcome.

Thanks for reading.

 

[90sNintendoKid]

This sounds great and I’ll happily admit some of it went over my head.

Does this allow the grouping of multiple dacs into one device? If so how are they synced?

 

[dualazmak]

Does this allow the grouping of multiple dacs into one device? If so how are they synced?

Even though I too have expected your point, the answer is "No they would not be synced perfectly"....
In the README.md page of LufiaASIO-Release, we read as follows;

Edit:
Furthermore, if you would be interested, please visit my posts #783 and #804 as well as #807 on my project thread describing a kind of "experimental quasi/sham tentative synchronization under very strict conditions" of multiple different-brand DAC units running on their own ASIO drivers under very strict conditions, which I absolutely do not recommend you utilizing in your daily audio listening sessions. My post #1,021 would be also of your interest; the negative result for multiple different-brand DAC units is the same with VB-AUDIO MATRIX.

 

[lini]

Hi everyone. I am Aspirin, the developer of LufiaASIO. Version 1.2.8 Alpha is my first public preview release. (...)

Cool project, man. Thumbs up for that!

Looking forward to see/read test results - especially as I could imagine, that people might be curious, whether LufiaASIO could also be an interesting alternative to ASIO wrappers like ASIO4ALL or the Steinberg built-in ASIO driver, even if the scope of LufiaASIO goes beyond the scope of a simple ASIO wrapper.

Greetings from Munich!

Manfred / lini

 

[dualazmak]

Yes, very much interesting new ASIO project!
My hearty congratulations go to OP @Lufia for on-going exciting development of LufiaASIO!

I have been using ASIO4ALL for long while in my multichannel audio project, and then I completely replaced it with VB-Audio MATRIX in late 2023; for the details my present audio setup, including all-ASIO routing using VB-AUDIO MATRIX, please visit my post #931 on my project thread.

At this moment, if acceptable at your end, would you please briefly describe similarities and differences LufiaASIO vs. VB-AUDIO MATRIX?