Whats the story with group delay?! Does it affect different subs in different ways? I know subs are already kinda slow as it is, compared to 6.5" midbass, but, how much does group delay affect the sound? I mean, will 30-40ms seriously affect the sound or be noticable (with rear loading)? i don't know what is a "good" level of group delay in an SQ setup, ideally, 0ms But, would 30-40ms be noticable? If so, approx. when would it "not" be noticed?!
Ta
Aaron

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I don't see any hard and fast rules as in "what is a good number?"

What is going to work best IMO is a smooth group delay curve without peaks and troughs. It tends to indicate the driver "likes" the way it is being loaded and performs well under those circumstances.

I can think of any number of sealed loadings which have "better numbers" than ported enclosures but there are plenty of ported enclosures that sound faster with "worse numbers".

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Ah, right Because all the boxes/sub combo's i've thought of, all come up with a small peak, then a big peak, typically about 25-40ms, depending on sub..... it's fairly large, not HUGE, but i'm using WinISD with a type R 12"... and about 70l ported to 26hz.... should go llllllowwwwww but i'm just worried about g.d....
Hmmm

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Noise producer - Clarion DRX9675
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-Team SQ, A Reality Not a Dream :)
-Before you criticize someone, you should walk a mile in their shoes. That way, when you criticize them, you're a mile away and you have their shoes.

Well comparing the type-R (which mate has) to the DDDrive (which i have) the type-R will have more group delay naturally, as it hits harder and its the nature of the sub.

To be honest i dont think the chart you are coming up with is a worry at all, every box i've ever designed has a peak somewhere (though i havent designed all that many ).

The last one i did is for the home sub, and despite the peak i havent noticed the group delay at all

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it also depends on what frequencys it is at - you are much more likely to notice the delay if it is at kick drum frequencys rather than at 30hz

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I have the 10" type R and the DDD like Bass. I am in slightly different position with my sub 2.2 metres behind the driver. But with time correction I zeroed everything on the sub.
Front and rear, left and right matched.
I found the kick drum best at 4ms delay to match the system with the DDD and 6ms with type R.
Hope this helps

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when designing an encolsure, the flatter the group delay curve the better, especially if you have time alignment correction.
if you don't have time alignment correction, then i'd try to keep it uder 15ms, but if it slips about 15ms around 40Hz i wouldn't be overly concerned.
if there is a big spike in the curve, then you could have SQ problems

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