Audison SR 6.600 – An Amplifier with Supreme Confidence!
The Audison SR range of amplifiers is not new. Lauded for delivering audiophile quality from a class-D topography, the range has been quickly adopted by discerning music listeners on the move. We take an in-depth look at the latest addition to the range.
With a huge range of specialist car audio equipment available, it is often human nature to look for new developments at the top of the tree. However, Audison and Hertz, apply just as much design work to medium—and low-priced products.
The SR range of amplifiers is a case in point. After the job was done in many respects with the Audison Forza range of amplifiers, Audison set their mighty brains to improve the sonic performance of lower-priced amplifiers.
This was an important target as trends change. In the past, car manufacturers dynamically adjusted the equalisation of head units to protect speakers from damage. However, this trend is now swinging the other way, and many factory source units are outputting lovely flat (ish) audio signals that need less work to reproduce in higher quality.
Although a flat response is not necessarily what people want to listen to, it is important to start with the entire frequency range as any deficiencies cannot be created by processing; they can only be adjusted in level.
There will always be a need for high-end audio, but DSP is no longer as essential as it once was for those working on a smaller budget. A discrete DSP, such as the Hertz H8, can always be added later. Audison wanted to provide audiophile performance for those in the market for a lower-cost compact, efficient class-D amplifier, and SR was born.
Audison refers to a package of technologies called ADT (Audison D-class Technology) as the key to sonic improvement with SR amplifiers. Essentially, this involves several highly technical changes to the fundamentals of D-class amplification based around the clock frequency and power supply. I could easily bore you with these, but I will leave you to visit the Audison website on your own.
We love Audison so much because they always put sonic performance at the forefront of everything they design. Sophisticated digital modelling (FEM) of a design concept is always trialled on the ears of actual people in blind testing. To claim that something sounds better, you need critical ears as well as clever brains.
Back to the Audison SR 6.600. The applications for this flexible amplifier are many-fold. For instance, having three stereo pairs of outputs, the SR could be seen as a perfect solution to the on-going issues with BMW audio systems. The standard system features a pair of tweeters, a pair of mids, and a pair of under-seat woofers. There are many other vehicles with a similar configuration, and the 6.600 would work as ably in these circumstances. In 6-channel mode, the amplifier will output 85 watts RMS to two pairs of channels for mid-range and tweeters while providing 110 watts RMS to the under-seat woofers. Lower frequencies often require higher power.
We know from experience that BMW head units/amplifiers tend to be underpowered, and simply correcting this can make a notable difference to the standard audio. The SR 6.600 is ideally suited for this but is also capable of much more if a speaker upgrade is on the agenda.
In this configuration, onboard filters can shape the sound's bandwidth on each pair of channels for distribution. You don’t want to be sending full-range information to the underseats or to the tweeters!
Onboard filters allow an experienced installer to tune a system and provide the right frequency band to the right speaker. All three pairs of channels can handle a full-range signal or be filtered for hi-pass (channels A and B) or Lo-pass (channel C). Specific technical specifications can be found at www.fourcaraudio.co.uk.
To expand on this slightly, channels 1 & 2 (Channel A) have an adjustable Hi-Pass filter, which can be adjusted to cut frequencies below 50 – 5kHz. In our BMW example, we could use this to run the tweeters depending on the tweeter used; this would usually be set somewhere between 3kHz – 5kHz. This means only frequencies above the set frequency would be sent to the tweeter. The filter limits frequencies using a curve rather than simply switching them off. In this case, the curve filters at 12dB/Octave. This detail may only mean something to the technically minded but is essential for installers and system designers.
All controls are mounted under a removable panel on top of the amplifier, allowing for future tweaks should they become necessary.
The filter can be switched out for other applications, resulting in a full-frequency response. This would be necessary for feeding a full-range speaker or a pair of components with a discrete passive crossover.
The SR 6.600 can be configured to run a multitude of system configurations. Inputs are received via quasi-balanced phono inputs (up to 8 volts RMS) or high-level speaker inputs (up to 40 volts RMS)
Channels 1,2 and 3,4 can be bridged to provide more power. Channels 5 and 6 can also be bridged. In this three-channel configuration, the power delivery increases to 2 X 280 watts full range and 1 X 370 watts. The higher-wattage channel would typically drive a subwoofer. An optional remote subwoofer level control (VCR-S2) can be added and provides -20dB – 6dB of boost to help overcome low-frequency cancelling caused by road noise or a throaty engine note, for instance.
The amplifier can drive a low-impedance load down to 2-ohm full range and 1-ohm subwoofer, and with careful installation, it can provide even more power. However, it is always important to remember that more power means better control; it is not all about how loud a system will be.
Thanks to an extruded aluminium chassis, the amplifier runs cool despite the high power available. No forced-air cooling is required, increasing mounting flexibility.
The SR 6.600 is the first amplifier in the Audison SR range to carry Japan Audio Society (JAS) Hi-Res accreditation, easily placing it at the top of the pile for amplifiers in this price class. The amplifier must have an expanded bandwidth (frequency range) to meet this exacting standard. In this instance, the SR 6.600 can amplify signals from 10Hz to 42kHz. Although this means it operates outside the bandwidth of human hearing, there are good reasons to do this regarding harmonics, beat frequencies and all-important timbre when listening to Hi-Res content.
We will be expanding on this requirement elsewhere in the magazine, as it is vital to high-quality listening.
This is yet another class-leading product from Audison as they continue to provide solutions for discerning music lovers on the move.
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