More on our New PRS-Series Class D Amps

Overcoming the Low Sound Quality of Traditional Class D Amps

Traditional car audio amplifiers generally use ‘Class A’ or ‘Class AB’ operation. While these categories offer good audio quality, they require large amplifying units to generate high power.

This is because the amps have low efficiency levels – so they run hot – requiring large vents to dissipate excess heat. Class D amplifiers are now gaining in popularity due to their size advantages. Digital technology makes them highly efficient, so amps can be incorporated into compact units. But this approach has drawbacks too as Class D products offer poor audio quality. They have therefore become common for driving subwoofers, where the power and audio quality balance leans towards high power. For full-range applications, however, Class D amplifiers are not a realistic option for most consumers.

The low sound quality of current Class D amps is caused by a number of factors: sensitivity to imperfect power supplies, distortion introduced by timing errors in the digital circuit and their load-dependent frequency response.

The ICEpower technology used in our PRS series multi-channel amps addresses these problems using a patented technique known as Controlled Oscillation Modulation (COM) in combination with MultiVariable Enhanced Cascade Control (MECC) featuring double loop compensation.

Double loop compensation uses two feedback loops to negate the essential weaknesses of Class D operation. One feedback loop uses the output of the power stage to compensate for any power-supply noise to suppress any distortion introduced. Another feedback loop uses the analogue output signal to compensate for load dependencies in the output stage, ensuring a smooth frequency response.

Another benefit of COM and MECC is that a lower switching frequency can be used, further improving efficiency and lowering distortion.

These amplifiers also offer a speaker input sensor, which allows them to be connected directly to the speaker outputs of original fit head-units. In this application, the amplifiers automatically recognise when the head-unit is turned on, making it an easy job to upgrade original fit audio systems with high grade, hi-fi amplifiers and speakers.

For more information:

• About ICEpower
• Browse our full Amplifier / DSP product line-up.
• See how Team Pioneer use our PRS Reference Series line-up in some of the industry's toughest and most demanding sound-off challenges and events.
• Find your nearest in-car audio shop, or you can contact your local Pioneer office