Apologies for the extreme length of this post – there’s a lot of material to cover on this topic. To download a copy of the Super Live Audio technical brochure, click here.
A New Standard
After years of research and development, KV2 Audio is pleased to announce a new standard in live sound reinforcement.
Super Live Audio or ‘SLA‘ has been developed through KV2′s efforts to achieve the highest possible dynamic range and the lowest possible losses, caused through distortion or the altering of signal as it passes through the audio chain. Further to this, rather than develop technologies that try to compensate or fix problems in a system’s design, KV2 focuses on building systems that are inherently superior from the start.
Our SLA standard reproduces high sound pressure levels in large spaces whilst delivering true dynamic range and source representation. There are a number of factors that KV2 have identified that make up SLA and the resulting benefits it provides to the listener. These factors include electronic integrity (settling time), digital sampling rates, pulse response, dynamic range and acoustic system design.
Please read on to learn how KV2 achieves maximum dynamic range and resolution to deliver unchanged and uncoloured audio reproduction at high SPL over large distances.
Definition and Distance
Fundamentally, the effect of a poor quality system comprising of inferior electronics, transducers and acoustic design is a lack of definition and detail, but equally important in a live audio situation is the distance in which a system can project clear defined audio. To maintain high-quality sound, especially at a long distance, it is vitally important that each part of the audio chain is of the utmost integrity.
The system must be capable of transferring an unchanged sound, including the ambience of a performance over distance at the required level to provide the greatest possible experience for the listener. As the area of coverage increases, the demand grows for system resolution. Sound pressure levels can reach values up to 140 dB, so the emphasis is on the dynamic range of the system. The system must not color or influence the sound quality; it must have minimum distortion and a maximum dynamic range. SLA technology has come about through KV2′s advancements in achieving these goals.
Standard electro-acoustic devices have a limited dynamic range and invariably produce distortion not related to the original signal (Non Harmonic Distortion). This distortion becomes apparent in the high frequency range significantly masking the weaker parts of the signal. This masking has the effect of erasing a large proportion of the detailed information thus causing a significant reduction in clarity. The artificially changed signal makes it impossible to transmit the ambience or real atmosphere of the original sound to the listener, particularly over distance.
Please read on to learn how KV2 achieves maximum dynamic range and resolution to deliver unchanged and uncolored audio reproduction at high SPL over large distances.
Dynamic vs Sampling
Live audio is very dynamic, yet a dynamic range of 130db is almost impossible for any digital AD and DA converter at the current sampling rates used to replicate. Dynamic resolution is directly related to the bit and sampling rates used in the digital conversion process.
At present, commercial digital audio commonly uses multiple-bit digital standard sampling, (PCM, Pulse Code Modulation). Industry standards have determined that a 24-bit/96 kHz sample rate (which corresponds to 2.8224 MHz 1bit PDM, Pulse Density Modulation, used in SACD), is adequate when professionally converting an audio signal consisting solely of harmonic signal components. In practice however, the audio signal consists of many signals, therefore it is complex and its properties are actually closer to random signals. The spectrum of random signals is infinitely wide, so when converting analog signals to digital, the sampling rate must be as high as possible in order to maintain quality of the transferred signal in full resolution.
At the current sampling rates utilized in commercial audio system design it is evident that their resolution is compromised as the frequency range increases. Much of the detail and ambience captured in the sound is related to this area. A decrease of information due to sampling frequency affects the sound as a loss of brilliance and intelligibility while increasing high frequency sizzle and distortion. In addition, when using DSP, there is additional information loss due to reduced DSP power, precision and limited processing time.
By increasing sampling rates the amount of transferred information increases, but sampling rates cannot be unlimited, so digital audio can never reach the quality of a high definition analog system. It is however necessary in some cases to use digital processing to correct certain aspects of the system in a professional live audio application, KV2 looked at ways of maximising definition and dynamic range in the digital realm.
KV2 undertook a different approach to digital. They looked at an alternate conversion process developed by Sony and Philips called Direct Stream Digital or DSD. The Super Audio CD (SACD) is based on DSD and unlike pulse code modulation (PCM) technology used commonly in pro audio applications and normal CD recordings, DSD technology is based on a one-bit ‘sigma-delta’ converter that produces a stream of pulses. The amplitude of the analog waveform is represented by the density of pulses, and is called Pulse Density Modulation. The resulting digital bit stream is encoded at enormous 2,822,400 samples per second! (2.8224MHz)
Practical listening tests were undertaken by our engineers to determine the minimal sampling frequency required to eliminate any audible information loss. The result saw KV2 design a circuit based around DSD with a sampling frequency of an incredible 20MHz, when using 1 bit sigma-delta PDM modulation. KV2s new digital converter delivers resolution 7 times higher than SACD. A special step compander circuit adds a further 20db of dynamic range to utilize the maximal range of the converter at low levels.
KV2 Audio utilizes hybrid signal processing, using the best of analog and digital technology to provide all necessary filtering, equalization and time alignment to their speaker systems. This best of both worlds approach provides unmatched dynamic range and audio reproduction.
To maintain a high-resolution audio signal, it is also important for the system to maintain the shortest possible impulse response time. Impulse response time is effected by settling time and circuit design in analog and by sampling frequency in digital. In the figure below it is evident that commonly used commercial systems, particularly digital, cannot pass the full resolution of the original signal. Impulse response time is effected in the digital domain by the sampling rate and in the analog signal path by the speed of the electronics (settling time) and control of the acoustic component motion (speaker movement). The change in the original signal caused through poor impulse response creates distortion.
Systems with long impulse response are unable to transfer high dynamics and high definition signals. SLA systems incorporate hybrid signal processing at an industry leading sample rate of 20MHz and a settling time of 1microsecond (1μs), to ensure audio reproduction with the highest possible resolution and definition.