The E65 LOGIC7 Audio System
The BMW E65 / E66 LOGIC7 audio system was manufactured by 'Harman Becker Automotive Systems' and features 9 separate audio channels consisting of 13 individual speakers. The distinctive LOGIC7 DSP algorithm was developed by 'Lexicon'. An overview of the system is shown below.
Vehicle Speaker Overview (9 Channel - 7.2 Surround)
The 13 speakers are split between two individual control units, the ASK (Audio System Controller) located in the dashboard, and the Top Hi-Fi Amplifier located behind the left boot cover. The channels are separated as follows:
ASK Speaker Outputs (4 Channels)
ASK (Audio System Controller):
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Front Door Channels (Left and Right) 100mm Midrange and 44mm Tweeter
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Rear Deck Channels (Left and Right) 100mm Midrange and 44mm Tweeter
Top Hi-Fi Speaker Outputs (5 Channels)
Top Hi-Fi Amplifier:
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Rear Door Channels (Left and Right) 100mm Midrange
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Dashboard Centre Channel 100mm Midrange
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Under Seat Channels (Left and Right) 210mm Subwoofer
System Fault Diagnosis
With the understanding of the LOGIC7 system described above, the speaker output faults can be diagnosed to either the ASK (Audio System Controller) or the Top Hi-Fi Amplifier relatively quickly.
It is incredibly common for the ASK and Top Hi-Fi Amplifier units to suffer from speaker output stage failures, the symptoms are usually one or more of the following:
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Intermittent channels, one or more speakers will cut in and out randomly.
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Popping, crackling, or heavily distorted audio.
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No sound at all from one or more channels.
There are some symptoms which can indicate a more serious problem which unfortunately cannot be repaired. These failures involve the processors used within the ASK and Top Hi-Fi Amplifier units, they are 'chip on board' and cannot be reworked or replaced. Symptoms usually include:
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Total failure of all output channels for one particular unit.
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The inability to adjust the EQ settings in the 'Tone' or 'Memory' menus.
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Intermittent resetting of the idrive every 1-2 seconds, usually with a pop or click from the ASK output channels.
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Some ASK units exhibit symptoms of one or two faulty channels that would generally be repairable, however on occasion the DAC (Digital to Analogue Converter) within the processor has failed and therefore does not output any sound to the amplifiers. This is rare and all ASK units are tested to ensure all channels from the DAC are working before further work is carried out.
