Sentinel keeps an eye out on Alcons systems6 July 2015
Alcons has developed Sentinel, a range of amplified loudspeaker controllers that are claimed to match precisely the requirements of its loudspeakers.
Sentinel – which has been demonstrated for some time as a concept by Alcons at trade shows – came about from Alcons engineers doing thorough, calibrated 1:1 listening tests between the company’s ALC series of amplified loudspeaker controllers and products from various leading amplifier brands.
“We compared sound quality on stereo imaging, depth, width and resolution,” says Alcons co-founder Tom Back. “Most people in the pro audio world would think that each amplifier of a given rating is the same, but we found that there are large differences between each model and the various technologies used.
“Of course, we did further testing on output, thermal behaviour, user interface, integrated processing platforms and serviceability, which also revealed lot of differences. Overall, with such high-resolution transducer technology as Alcons pro-ribbon, the differences were too big for us to ignore.”
Rather than entering into an OEM agreement with an existing amplifier manufacturer, Alcons decided to develop its own proprietary platform. This, it says, was to enable it to achieve a unit that would allow its systems to deliver everything that modern audio professionals demand with absolutely no loss of audio quality.
The Sentinel features 4-in/4-out input matrix routing, with an internal 96kHz sampling rate. Thanks to its custom-designed sample-rate conversion, Sentinel accepts any signal between 44.1kHz up to 192kHz digital AES3 format.
The future-upgradable powerful DSP engine is said to enable minimal latency during processing of even the most complex (IIR, FIR) algorithms.
DSP features include parametric equaliser (including shelf, notch, high/low-pass) and delay per channel, factory presets for all Alcons systems and configurations.
The ‘linear’ preset enables the Sentinel to be used with third-party speakers, while maintaining full DSP functionality.
The four independent, patent-pending Class D amplifier stages and 2 redundant switch-mode power supplies all feature a microcontroller, allowing all parameters to be monitored and guided via the internal communication network. This means maximum operating efficiency (even with one power supply shut down) and extensive status/application logging can be maintained at all times.
The modular construction makes possible future hardware upgrades (for example, adding more powerful processors), and also offers easy field servicing.
The Signal Integrity Sensing (SIS) circuit dynamically compensates for impedance effects in long speaker cables and connectors, resulting in a tight sub and bass response, matching the fast-transient response of Alcons’ pro-ribbon mid-high frequency reproduction. This circuit doesn’t require any manual presetting, but operates dynamically, on SIS pre-wired systems.
The Sentinel is operated by a Linux-based main controller, through a large, intuitive colour 480 x 272 TFT touchscreen and RGD-LED rotary encoder.
Remote control requirements are served by ALControl, Alcons’ proprietary ALC control software protocol,which can control individual or clusters of Sentinels via Mac or PC platforms. Control from mobile devices is possible through a VNC app.
Spare module slots and two RJ45 connectors enable optional audio-over-network control.
Sentinel comes in a 2U rack mount package in two formats: 4x 750W (Sentinel3) and 4x 2500W (Sentinel10) output, weighing 8.8kg and 11.6kg respectively.
“The main focus in the development of the Sentinel range was to obtain an ‘audiophile-grade’ signal path and a surplus of headroom under any circumstance, to get the maximum performance out of Alcons sound systems,” said Back. “It is designed to offer the highest possible sound quality and most realistic sound experience, at any sound pressure level, in any application.
“It has meant that our R&D path took longer than the ‘short cut’ of an OEM agreement, but it has definitely paid off. We can truly say that the combination of Alcons sound systems and the Sentinel platform raises the bar for maximum obtainable sound quality in sound reinforcement. It sets new standards of hi-fi sound at concert SPLs. And, most importantly, it’s a future-proof investment!”