- Feb 29, 2016
To first introduce Waversa, I believe it best to discuss what is at the heart of their product line, and that common denominator is the Waversa Audio Processor. The Waversa Audio Processor is fundamentally unique in the industry, a very different approach to digital processing, designed from “the ground-up”. The Waversa approach encompasses processing by both in-house designed and built processing hardware as well as integrated custom software, rather than by using what is available in, or software manipulation of processing by, “off-the-shelf” DAC chips, or other purely software-based processing methods.
WAP (Waversa Audio Processor)
Waversa Systems’ WAP (Waversa Audio Processor) provides:
- a hardware-based processing method with a very low jitter rate and highly accurate timing
- a proprietary solution from digital input to processor
- Dual WAP, capturing all signals on the optimized route
- Centralized clock management in the signal path
- Technology to minimize Quantization Error
- huge information processing up to 32Bit 1.5MHz
- the highest level signal restoration algorithm by applying medical technology
Generally, upsampling uses an FIR filter (Finite Impulse Response, fixed-form impulse response filter). Interpolation is performed during the upsampling process to correct the sound quality. FIR Interpolation is a mathematical calculation that estimates and fills between digital points.
In the case of the Saber ES90x8 series, such FIR filters are basically built-in and easily implemented by DAC manufacturers. Waversa Systems uses a proprietary WAP instead of the basic FIR filter included in the DA chip. Waversa Audio Processor (WAP) is designed in-house with a multi-stage structure including a number of proprietary FIR filters and IIR filters (Infinite Impulse Response Filter) and performs high-resolution upsampling. This high-resolution upsampled signal is processed through thousands of iterative calculations using state-of-the-art source estimation algorithms to reduce digital errors and create a waveform that is as identical as possible to the original analog signal. This is the role of WAP.
Figure 1: Software processing using ES9038PRO and Waversa hardware-based WAP Processing
The software processing method has elements that cause errors because the processing is sequential and complicated. On the other hand, in the hardware processing method, since signal processing is performed once, at the same time, there is no room for jitter, and the timing of the audio signal is exactly the same.
Waversa Systems’ digital signal processing is hardware based, so digital signals are processed simultaneously in a simple, optimized path resulting in fewer errors, and the timing of the audio signal is handled more accurately.
Dual WAP captures all signals in order to dramatically increase processing speed and efficiently manage signal processing. The first WAP (P1) processes all input signals, and the second WAP (P2) receives signals processed by P1 on I2S and decodes signals with clocks according to sampling rates. In this way, by assigning a unique role to each digital processor, signal interference is minimized, more sophisticated clock management is performed, and sound quality benefits from accurate signals that do not compromise digital signal integrity.
Figure 2: Dual WAP processing
The most recently developed WAP has greatly increased the amount of data that can be processed. This new WAP has succeeded its predecessor (24Bit / 368kHz) with 32Bit / 1.5MHz data processing. For comparison, in 16Bit, 65,532 digital signal processes are performed; in 32Bit, there are 4 billion digital signal processes, and the sophistication of signal processing is dramatically increased. This has made it possible to generate digital signals that are closer to analog, and the subsequent digital restoration technology has become more accurate.
The heart of WAP lies in signal restoration using 32Bit 1.5 MHz data processing, allowing for processing of huge amounts of information:
Figure 3: Data signal conformity with 16 bit/44.1, 24 bit/192, and 32 bit/1.5 MHz processing speeds
To put it simply, the improved internal processing speed of 32Bit / 1.5MHz is similar to upgrading from DVD quality to 4K quality. This dramatically increases the detail and dynamic range that can be expressed.
The higher the WAP level, the more sophisticated the processing per unit time. This improves sound image and detail, overall producing a more natural sound. The tone of the instruments is also flexible, organic and easy to hear. Each Waversa product has different processing capabilities that when linked create a cumulative benefit.
WAP / X (Waversa Audio Processor Extension) that reproduces the sound of vacuum tubes
The characteristics of a vacuum tube amplifier that has been deeply loved for its warm tone are reproduced using digital technology. These overtone characteristics of WAP / X were developed focusing on the 1940's WE300B.
The technology adds a sense of overtones in WAP / X and WAP, realizing the sound of a transparent and warm vacuum tube, digitally reproduced technology designed to be upgradeable in future firmware updates.
High-end audio processing is a fairly complicated process involving a huge amount of data in real-time. Waversa addresses this in two parts. The most recent breakthrough is to task the new generation field-programmable gate array, which unknown to most of us, including myself, is an exceedingly complex fast logic circuit that has proven to handle these resource-intensive algorithms. By tasking the FPGA to take on the overtone processing algorithm [WAP/X], this processing can be done accurately to many harmonics in real-time.
Some say that analog sounds are bright and warm, while digital sounds are cool and crisp. It is also thought that harmonics are masked by jitter and electrical noise inherent in digital equipment. All DAC manufacturers have understandably focused on minimizing these issues. Waversa over the years was able to characterize the harmonics of a classic 1942 Western Electric 300b and digitally replicate using a hardware-based algorithm integrated into both the new generation FPGA and Waversa Audio Processor (WAP). As a result, you can feel warm overtones without the vacuum tube. In fact, if you want to hear the higher harmonics present in music but lost in the digitization of the music process, the only way to do so is virtually because there is a limit to the capability of a vacuum tube, no matter how good it is. The degree of harmonics is adjusted by the end-user as well as bypassing this type of processing.
Dynamic Range Enhancement is another Waversa-unique processing algorithm. It's not a volume control or output gain setting, but it is also adjustable by the end-user. This novel setting brings life to compressed recordings. Both the Harmonic (WAP-X) and Dynamic Range Enhancement algorithms provide significant flexibility - and more is not necessarily better. Settings are recording and end-user preference dependent. They act as seasonings that can make a gourmet meal truly sublime.