LFE EQ and Sub Mix

Where does the Audyssey EQ take place in the LFE channel during its calibration? Before or after the point where the other channels are mixed in when you set their speaker sizes to small and adjust the crossover frequencies?

Regards

Paul

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5 Comments

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    Chris Kyriakakis

    Hi Paul,

    The Audyssey room correction filters are applied to each speaker channel individually.  There is a filter created for each speaker and sub and these filters correct whatever content is sent to them.

    Note: there is no such thing as an LFE channel.  LFE is a content track that can play from the sub or the main speakers depending on how your system is set up.  

    The subwoofer channel plays back the bass below the crossover point of each speaker *plus* the separate LFE track if it exists.  For example, in 2-ch content there is no LFE track.

    So, the filters sit there after bass management and "wait" for content to come to them.  If you set your speakers to Large the subwoofer filters will have little to do because no bass will be sent to them other than the occasional content from the LFE track.

     

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    Paul Berg

    Chris,

    Thanks for your prompt response. Unfortunately I used the wrong term when describing the subwoofer channel.

    I therefore understand from your reply that all Audyssey EQ on the sub woofer channel is applied after the bass management and combining of all the sub signals, including the LFE track if it is present.

    This is what I would have expected. However I am unable to find any applied Audyssey EQ on my sub woofer channel when I sweep it with Audyssey in and then out. Both sweeps are virtually identical to my eyes.

    If I use my SMS-1 to EQ the sub woofer channel manually I can easily get it +,-2dB from 15Hz to 100Hz, but if I sweep it after the Audyssey process it is +,-15dB  over the same frequency range. I also have to phase invert the sub phase to remove a 15dB dip at 63HZ.

    Any insights into what I am seeing, or doing wrong?

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    Chris Kyriakakis

    Hi Paul,

    Are you feeding the SMS signal into the Denon so that it can pass through the Audyssey subwoofer filter?  Which input are you using?

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    Paul Berg

    Chris,

    The SMS sweep tone is being fed into a stereo analog input of a Denon AVP and the Audyssey EQ is being applied to that input and the sub output ( AL24 and Audyssey is lit up on the display). I can change the X-over frequency and see and hear its effect and I can switch Audyssey in and out and see and hear its effect. What I do not understand is why the Audyssey EQ did not seem to make ANY changes to the huge peak (+15dB) at 32Hz.

     

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    Chris Kyriakakis

    Hi Paul,

    A single position measurement will not give you a good indication of bass performance.  You will need to take measurements in the same locations as the Audyssey mic was and then find a way to average them.  Sine tones and single mic positions can be off by many dB--it's a very inaccurate method of measurement.

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