July 2022


A faithful re-creation of the original experience,

beyond any numerical representation.


There is sound beyond sound.  The sound beyond what our ears can hear is critical to the experience.

The experience is more important than the measurement.

AKM's years of experimentation have yielded a multitude of techniques to create sound that resonates, emotionally.

VELVET SOUND addresses every aspect of sound, building a world of authentic sonic experience.

OSRD Technology:

More expressive audio

Low out-of-band noise

AKM's OSRD (Over Sampling Ratio Doubler) has a signal bandwidth of approximately 200 kHz, which is 10 times the audible range (~ 20 kHz).

It is possible to achieve lower out-of-band noise in the frequency band beyond the audible range by increasing the OSR, but this comes at a price, as power consumption increases due to higher-speed operation.

OSRD technology eliminates this trade-off by allowing OSR to be increased without raising power consumption.
VELVET SOUND DACs have adopted this technology, resulting in ultra-low out-of-band noise. (Patented in 2016)

OSRD Technology

Plot of out-of-band noise at 1kHz, 0dBFS input
The noise floor up to about 200kHz is flat, enabling more broadband signal re-creation.

Layout technology:

Delicate and bold expression

VELVET SOUND's layout technology is built to honor the original signal content.

The noise resulting from the operation of switching digital circuits is reduced to the utmost degree.  All noise-mixing paths to the signal are eliminated.

Beyond just the audio content, the timing references are also thoroughly separated from noise sources, greatly improving noise rejection in the resulting audio signal.

VELVET SOUND devices use a fully symmetrical left-to-right layout.  Features such as channel-independent assignment of analog power supplies and signal reference terminals enable smooth and flexible signal flow.

This approach to layout and signal routing enables the most delicate and bold expression of sound possible today.

Sound color IRD filters:

More colorful sound

Everyone is aware of the importance of accurately conveying the signal waveform itself, but what about its transient response?

After much experimentation focused on the signal waveform, AKM has developed the IRD (Impulse Response-Designed) Filter, which allows the user to control the transient response of the signal.


In PCM mode, six types of digital filters enable music playback optimized for a variety of settings.


In PCM mode, four types of digital filters are available, enabling optimization for a variety of settings.

DAC: Sound Colors (Impulse Response Designed Filter) DAC: Sound Colors
ADC: Sound Colors (Impulse Response Designed Filter) ADC & SRC: Sound Colors