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Author Topic: Group Delay  (Read 17250 times)

Irwan Prasetyo

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Group Delay
« on: November 12, 2012, 03:07:59 pm »

Hi all...
what is group delay??and what the different between group delay & phase delay??

Thanks for any advice
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g'bye, Dick Rees

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Re: Group Delay
« Reply #1 on: November 12, 2012, 03:45:14 pm »

Hi all...
what is group delay??and what the different between group delay & phase delay??

Thanks for any advice

http://en.wikipedia.org/wiki/Group_delay_and_phase_delay
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George Friedman-Jimenez

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Re: Group Delay
« Reply #2 on: November 12, 2012, 04:43:59 pm »

Well that certainly cleared that up. Thanks Dick.
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Charlie Hughes

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Re: Group Delay
« Reply #3 on: November 12, 2012, 05:36:42 pm »

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Irwan Prasetyo

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Irwan Prasetyo

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Re: Group Delay
« Reply #5 on: November 12, 2012, 11:48:48 pm »

Try this one instead, http://www.excelsior-audio.com/Publications/Phase_Response_&_Receive_Delay.pdf.

After that you might find this one interesting http://www.excelsior-audio.com/Publications/Subwoofer_Alignment.pdf.

Thanks Charlie….I'll read it first and if i have some question i'll post in here
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Phil Graham

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Re: Group Delay
« Reply #6 on: November 19, 2012, 12:11:32 pm »

Hi all...
what is group delay??and what the different between group delay & phase delay??

Thanks for any advice

Read Charlie's article. Limitations on receive delay fidelity are an important issue in measurement.

Mathematically group delay is the negative first derivative of the phase wrt frequency, as discussed in the Wikipedia article. Now that's not very useful if you're not mathematical.

So, practically, what does group delay tell you?

Group delay takes the phase, which is one way of book keeping relative arrival times of each frequency, and provides a different view of this information. Rather than having to discern how the phase angle at any given frequency corresponds to the arrival time, a group delay plot instead shows the delay time (in ms) vs. frequency directly. A group delay plot makes it easy to see whether a woofer or horn is leading/lagging. It also make it easy to see the extra delay time added by the phase response of the filters we apply to audio signals.

In summary, it is a different and more clear means of looking at the relative arrival time of each frequency that is emerging from a device/speaker that is being measured.
« Last Edit: November 19, 2012, 06:23:15 pm by Phil Graham »
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Mac Kerr

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Re: Group Delay
« Reply #7 on: November 19, 2012, 12:41:57 pm »

Group delay takes the phase, which is one way of book keeping relative arrival times of each frequency, and provides a different view of this information. Rather than having to discern what the phase angle at any given frequency is, a group delay plot instead shows the delay time (in ms) vs. frequency directly. A group delay plot makes it easy to see whether a woofer or horn is leading/lagging. It also make it easy to see the extra delay time added by the phase response of the filters we apply to audio signals.

In summary, it is a different and more clear means of looking at the relative arrival time of each frequency that is emerging from a device/speaker that is being measured.

Nice explanation.

Mac
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Jim McKeveny

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Re: Group Delay
« Reply #8 on: November 20, 2012, 07:47:38 am »

From my experience (and perhaps I am incorrect), the most apparent audio demonstrations of excess group delay occur in regard to transient response, esp in the SLF range. High-order bandpass boxes have enhanced steady-state sensitivity, but at the cost of hearable group delay.

In simpler terms:  Keyed & plucked steady-state bass tone envelopes are fine, but kick drum and the like suffer.
« Last Edit: November 20, 2012, 07:58:07 am by Jim McKeveny »
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Mike Christy

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Re: Group Delay
« Reply #9 on: November 20, 2012, 09:56:09 am »

From my experience (and perhaps I am incorrect), the most apparent audio demonstrations of excess group delay occur in regard to transient response, esp in the SLF range. High-order bandpass boxes have enhanced steady-state sensitivity, but at the cost of hearable group delay.

In simpler terms:  Keyed & plucked steady-state bass tone envelopes are fine, but kick drum and the like suffer.

Just thinking through what you are saying...not that I agree...That the coherant phase relationship of all the frequencies (from the lowest to the highest) in a bandpass system is poor, and a gd error (relative to something else) can be heard when a steep/short attack signal like a kick hit is propagated through the system (although a plucked string can have a steep attack also), and the gd/phase errors can be heard, those errors are between the original sound (beater) and the system sound (PA)?

Maybe if LF system phase alignment is out of wack, the short kick signal is more suseptable to phase cancelations, where a sustaned bass is not as it natuarlly rolls along it's natural envelope.

Phillip, can I have clarification, pleeeeeeeeeeze?



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Re: Group Delay
« Reply #9 on: November 20, 2012, 09:56:09 am »


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