Originally Posted by Steve1981
It's telling you that quite literally, the output at 20Hz for example, is delayed by about 110ms. This is a predictable result of a bass reflex enclosure combined with a steep high pass filter to protect the driver. Audibility is debatable; no study has proven the threshold one way or the other at these frequencies. Of course, as Ed at SVS pointed out to me, given that GD is inherently related to frequency response, the room and any EQ/auto setup easily have the potential to change things up considerably...
I've been commenting on "decay" as opposed to "delay." For me, decay or a lack of decay equals a tighter or bloated bass signature. As to the rest of it (tuning frequencies, the style of enclosure, other than Audyssey analyzing and EQ'g the room), it's all above my pay grade.
The PB12-NSD has a purposefully flat FR and good bandwidth linearity (basically, flat FR at the limit), which is what you're seeing.
And I'm loving on it.
Natively (ie without EQ), the Empire well...does not. However, aside from right around the tuning frequency of the PB12, the Empire offers considerably greater output, as one should expect from dual 15" drivers and 50% more juice. Of course, that the PB12 can keep up at tuning frequency is a great demonstration of the inherent efficiency of a vented box at tuning frequency.
And for the price, I'm loving on it. In the words of one Homer Simpson,......Mmmmmmmmmmmmm!
The deeper you go on this issue, the less I know; which in this case, ain't hard as now I get to read up on; "Group Delay."
I'm coming from a pair of nineteen year old 12" subs that at best, get down to 28Hz. These new subs are a marvel by comparison, on the order of two, if not three magnitudes worth of improved sound quality (okay, three might be a stretch) that's why the intense interest as even though only a pair of 12" subs, the replacement upgrade is going be a huge sonic improvement. I honestly don't think our personal listening levels will take advantage of a pair of larger subs. I finally convinced the wife that dynamic range demands you keep your hands off the remote. That was a coop in of itself as once she understood the why, she was good.
Honey, it's how the mixer, mixes the dynamics of the movie track. It's dialogue vs the booms and the bangs and then back to the quiet passages of whispers and normal office conversation.
We were watching a John Travolta/Samuel Jackson movie; "Basic." Huge dynamic range in that mix from field office interrogation to battlefield training exercises. My opinion, the move was an intentionally terrible mis-representation of today's advanced Army Ranger training but was an excellent example of the dynamics of a well done movie sound track mix. Either which way, it made sense and my wife let the volume stay on the level I had set it at. Yaaaaaaaay! I win one.
And yes, a big shout out to Ed's thoughtful passion and his willingness to sincerely help bring neophytes up to speed regarding subs and his product line.Currently reading this PDF article regarding "Group Delay."
I forget, was the "Hilbert Transform" discussed at the end of "Acoustics 101" or the beginning of "Acoustics 1A?"