Subs & Group Delay

Hi Duke, you said, "In my opinion the in-room frequency response makes a bigger difference."

How close of a freq response do you think is "needed", for low freq say from 20 to 100hz to sound good? My thought is +- 3db with one to two peaks and nulls up to 5 to 6db will be close enough for good playback, in most rooms.
What are your thoughts on this?

Bob

Hi Shadorne, I dont know where to go with my reply to your post above (six above). But I must say it has me "confused". Where you wrote,

"It is pretty impressive yes but a far cry from a crushing SPL due to the fact we can barely hear 20 Hz. For comparison it would sound as loud as a 40 db SPL note at 1 Khz...a little above the rustling of leaves. The good news is that if your sub can achieve 115 db SPL then it suddenly becomes much more audible - as 120 db SPL will sound like 80 db SPL at 1 Khz - so clearly audible even above a conversation. Also there is not much at 20 Hz anyway so the biggest benefit is the lack of distortion at higher harmonics rather than any bone crushing sound.

The reality is that a great sub will NOT sound devastating on a 20 Hz pure tone at 100db SPL - is will be mostly inaudible if it is a good high quality sub!!!"

I am actually having a hard time digesting this. If you would like to try re-explaining this to me I would be obliged. I am not sure how I want to counter to those statements. Perhaps we can dissect it at some point and discuss it that way. Not trying to be argumenative, but I do belive you need to perhaps rethink this.

Or perhaps I DO!

Bob

Hi Shadorne, Now I am with you! But I think the numbers and their implications are a bit exaggerated.

It looks to me you are using the Robinson Dadson cure as opposed to the Fletcher Munson. I see that at 80db the R-D curve is up 30db (not 40db) at 20hz while the F-M curve is only up 10db at 20hz. But even so with the R-D curve at 40db you are then looking at 50db up at 20hz, still not even close to the 60db that you mentioned to sound like rustling leaves.

I do think, now here we go, that the R-D curve is not as useful as the F-M curve. I believe the F-M curve to be the more accurate curve for our purposes. And yes thats good for me as now I do only have to be 10db up at 20hz as opposed to the 30db as suggested by R-D. Wow thats a big difference (20db). That is four times the difference between the two and the implications of power requiremens are huge. I will go with the F-M just because it is at least possibly obtainable by most audiophiles. And no I am not wimping out:)

Bob