Good Group Delay? - Home Theater Forum and Systems - HomeTheaterShack.com

Old 05-24-07, 09:51 PM Thread Starter
Senior Shackster

Jerm357

Join Date: May 2006
Location: Detroit
Posts: 299
Good Group Delay?

Would you say 6ms at 30hz and 18 ms at 20hz is considered good group delay or no?
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Old 05-25-07, 06:32 AM
Senior Shackster
Matt

Join Date: Feb 2007
Posts: 355
Re: Good Group Delay?

i always try to stay under half of a wavelength of the frequency (especially in audible frequencies) and especially under one wavelength... I cannot remember where I read this but I believe I read it online. For example:my sub
@50hz - 7.8 ms
@40hz - 7.5
@30hz - 7.7
@20hz - 18.3
@15hz - 79.45** this is right around the tuning frequency of the subwofer...
@10hz - 23.3

now, since we are dealing with ms (1/1000 of a sec) we can divide 1000/(Frequency calculated for) which will give us the time of one wavelength. 1000/50= 20ms per wavelength, since my sub is at 7.8, I consider it to have a good group delay.

at 15 hz, the wavelength lasts ~67 ms, I have 79 however 1, I am not playing much content at this frequency 2, this is a tactile frequency rather than an audible one so it is not necessary to have such a low group delay (my opinion)

please remember that any filtering (EQ) will add groupdelay to the sound; if you can obtain the eq values you can punch them into winISD assuming you are using that program, and see the 'full' group delay for the entire signal path, not just the speaker (the speaker will most likely have the most group delay though) Hope this helps.

-Matt
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Old 05-25-07, 06:43 AM
Senior Shackster
Matt

Join Date: Feb 2007
Posts: 355
Re: Good Group Delay?

you can also look about it on this site:

1000/30=33, you have 6, GREAT
1000/20=50, you have 18, great imo, it falls below half a cycle.
in the linkwitz lab article, i skimmed it and noticed something about 50ms being percieved as an echo... from these numbers im assuming its a sealed box? or a smaller sub enclosure, my gut says you will be fine as far as group delay.
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Old 05-25-07, 12:13 PM Thread Starter
Senior Shackster

Jerm357

Join Date: May 2006
Location: Detroit
Posts: 299
Re: Good Group Delay?

The sub is already built, so I was just wondering how good my group delay was. It peeks at 14hz and hits a wapping 58ms but thats in the inaudible range so Im not too worried because it sounds realy good to me. Thanks you for your responce.

Last edited by Jerm357; 05-25-07 at 12:33 PM.
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