Tech Talk
ARCAM’s AEQ Digital Processing
When a particular speaker profile is selected, the audio signal is processed in the digital domain by applying several Parametric EQ’s that have been designed to optimize the frequency response of the speaker.
For those SA35 and SA45 analogue purists, it should be noted that all analogue inputs, including the built-in MM and MC phono stages, keeps the audio signal pure analogue by default. However, by selecting a speaker profile of the ARCAM speakers the audio signal enters the digital domain for optimization.
The built-in DIRAC room correction can also be used to further benefit the complete system optimization by working in addition to the AEQ profiles by measuring the room response after the AEQ Speaker profile has been applied.
To achieve the same level of improvement using passive cross-over components and refined transducers would be impossible to achieve cost effectively. And ARCAM’s approach to AEQ takes it one step further still…
So, what exactly is AEQ (old approach)?
Anechoic chamber EQ is the calibration process designed to remove peaks and dips and makes an on-axis response of a loudspeaker as flat as possible based on the measurement taken in the reflection-free environment such as an Anechoic chamber. This process corrects most of irregularities in transducers & crossover networks and does not correct any interferences caused by the room. This old approach of making the on-axis response perfectly flat without considering the consistency of off-axis responses might cause the loudspeaker sounds harsh, unnatural and unpredictable in the real room.
What is different about ARCAM’s AEQ ?
It is a similar process to the above by correcting irregularities in transducers and crossover networks but based on the Spinorama measurements instead of on-axis measurement only.
Spinnorama is a set of curves which summarize the loudspeaker’s performance in a way that reflects human auditory perception. It was developed by Dr. Floyd Toole/HARMAN and now it is part of the CEA/CTA-2034 standard. The Spinorama curves display data such as Listening window, Early reflections, and Sound power which were derived from on and off axis response of 36 horizontal measurements and 36 vertical measurements. These curves focus on how the loudspeaker will be perceived by listeners in typical listening environments and bridge the gap between raw measurement data and real-world listener experience.
Since ARCAM’s AEQ is based on Spinorama measurements, the consistency of the Listening window, Early reflections, and Sound power responses are taken in consideration together with the on-axis response during the calibration process. This process results in loudspeakers with smooth, consistent off-axis behavior, and predictable performance in various listening conditions.
ARCAM R35 Spinorama without AEQ
ARCAM R35 Spinorama with AEQ
Summary:
While anechoic measurements provide a clean and consistent baseline, Spinorama expands this into a multidimensional understanding of speaker behavior. Effective equalization must consider not only on-axis performance but also off-axis consistency and real-world listening conditions. Ultimately, the combination between good Spinorama measurements of ARCAM loudspeakers and AEQ presets featured in ARCAM AV & Streaming Amplifiers leads to better-performing and more predictable audio systems.
The Speaker matching profile feature is available in the ARCAM Radia AV amplifiers which will start shipping in early May and a software update will be available for the ARCAM Radia Streaming Amplifiers in June.