In Broadcast - April 2012 - 64

WWW.INBROADCAST.COM | ISSUE 7 - APRIL 2012

InAUDIO
Maintaining Audio Quality
Audio processors change certain characteristics of the original programme material in the quest for positive beneﬁts, says Peter Lee
These beneﬁts include increased loudness, improved consistency, and absolute peak control to prevent distortion in the following signal path and/or to comply with government regulations. The art of audio processing is based on the idea that such beneﬁts can be achieved while giving the listener the illusion that nothing has been changed. Successful audio processing performs the desired electrical modiﬁcations while presenting a result to the listener that, subjectively, sounds natural and realistic. This sounds impossible, but it is not. Audio processing provides a few benefits that are often unappreciated by the radio or television listener. For example, the reduction of dynamic range caused by processing makes listening in noisy environments (particularly the car) much less difﬁcult. In music having a wide dynamic range, soft passages are often lost completely in the presence of background noise. Few listeners listen in a quiet environment. If the volume is turned up,
Peter Lee, Vice President of European Operations / Director of Sales

6585 model

subsequent louder passages can be uncomfortably loud. In the automobile, dynamic range cannot exceed 20 dB without causing these problems. Competent audio processing can reduce the dynamic range without introducing uc g objectionable side effects. s. Further, broadcast st programme material al typically comes from a rapidly changing variety of sources, most of which were produced with no regard for the spectral balances of others. Multiband limiting, when used properly, can automatically make the segues between sources much more consistent. Multiband limiting and consistency are vital to the station that wants to develop a characteristic audio signature

and a strong positive personality, just as feature ﬁlms are produced to maintain a consistent look. Ultimately, it is all about the listener experience. Good broadcast operators are hard to find, making artful ad automatic gain control auto essential for the correction esse of errors caused by distractions or lack of skill. Also, the regulatory authorities in most countries have little tolerance for excessive modulation making peak limiting mandatory for the regulated public airwaves. OPTIMOD-FM, OPTIMOD-AM, OPTIMOD-DAB, OPTIMOD-TV and OPTIMOD-PC have been designed to meet the special problems and needs of broadcasters and netcasters while delivering a quality product that most listeners consider

highly pleasing. However, every electronic communication medium has technical limits that must be fully heeded if the most pleasing results are to be presented to the audience. For instance, the audio quality delivered by OPTIMOD is highly inﬂuenced by the quality of the audio presented to it. If the input audio is very clean, the signal after processing will probably sound excellent, even after heavy processing. Distortion of any kind in the input signal is likely to be exaggerated by processing and, if severe, can end up sounding offensive and unlistenable. Processors must be judged on how they perform with the many different types of programme material used in a given format and ultimately should be judged based on their ability to attract and hold a given broadcaster’s target audience. There is no substitute for long-term listening. ■ Based on an original article by Bob Orban and Greg Ogonowski.

RME Announces HDSPe MADI FX
At the Musikmesse, Frankfurt, RME presented the new HDSPe MADI FX PCI Express card
RME hold out the HDSPe MADI FX as a “milestone” both in the history of audio interface cards in the past two decades and within their series of devices. The HDSPe MADI FX features 390 audio channels. Three MADI I/ Os – two optical and one coaxial – are accompanied by one AES/EBU I/O and one analogue monitoring output. To complete the feature set, a word clock connection and four MIDI I/Os were added. Only one PCIe slot is required on the motherboard, plus one free slot opening on the case. To guarantee RME’s low latency performance with such a huge amount of audio channels, the HDPSe MADI FX introduces a newly developed modular Hammerfall Pro Audio Core. The high-tech core will process three times as many channels as the channel count of the previous MADI ﬂagship, while reducing the system load and enabling ultra-low latencies down to 32 samples on modern computers. A sophisticated new efﬁciency technology will automatically deactivate currently unused channels, so that they require no processing power or bandwidth. A simple stereo playback will not require any more performance than from a standard stereo audio card

– despite the use of a professional multi-channel system with almost 400 channels. The new core technology is accompanied by a special version of TotalMix FX, which allows using the channel count in an efﬁcient and practical manner. The addition of numerous performance optimisations ensures that the 4096-channel mixer of the MADI FX responds just as smoothly as its 1800-channel counterpart in the Fireface UFX. A new and faster DSP allows for a greater number of EQs and compressors. An innovative new layout of TotalMix enables ergonomic handling of the enormous number of channels. A special option makes it possible to visually hide unused channels. The 192 kHz RME effects engine allows latency-free monitoring with numerous effects like EQs, compressors, reverb, and echo rendered directly on the hardware of the card, independent from the DAW software in use. The integrated TotalMix matrix

HDSPe MADI FX

conveniently allows the use of the card as powerful MADI router. Unlike most other router solutions, each channel can be routed individually. RME’s Seamless Redundancy Operation uses the cards’ three MADI receivers to provide professional users with state-ofthe-art fail safe operation. The audio data is not interrupted when switching to another input. In SRO mode the card operates as single MADI input device, recording up to 64 channels. As soon as the current input fails the audio data received from one of the other two inputs is used. Shipping in May 2012, the HDSPe MADI FX works on Windows and Mac OS. ■

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In Broadcast - April 2012

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