Subwoofer Impulse Response

[whoareyou]

This is a simulation from 5.1 setup. I was wondering about the subwoofer (black rounded off line) on this graph. My subwoofer always shows this rounded off simulation result. Most other graphs seem to show the subwoofer with a better response than this.
It all sounds good, but I was just wondering if this is indicative of something with subwoofer i.e sub level too low, subwoofer just not that good (it is HSU stf-2 in case you are wondering)?

I've tried raising the sub's level, but I start getting too much rattling in my room and then measurement usually fails.
Overall, I believe the impulse response is a little low, but that seems to be because I have 16db correction with the filter for this simulation. Regardless, the sub response always looks like this on my graphs..

 

[hulkss]

Make a target frequency response for what you would like your subs response to be. Then look at the step response of the target. That's what you are going to get if the correction filters work perfectly.

Here's some examples. First a response that extends to 16 Hz at the bottom.

Here's the minimum phase step response:

Here's the linear phase step response:

Now with a super deep 3 Hz frequency response:

Here is the minimum phase step response:

Here is the linear phase step response:

As can be seen, the linear phase response is beginning to look a bit like a proper square wave step. Both responses will look like a square wave step if the frequency response extends down to DC (zero Hz).

I have been getting good results with a linear phase target and filters that are flat in magnitude as the subwoofer response drops on the bottom end. This avoids the need for high latency linear filters or the resulting phase shifts of minimum phase filters at very low frequencies.

 

[juicehifi]

View attachment 49848

The sub has a rounded entry because of limited bandwidth. It can not match the rise time of a tweeter.

 

[whoareyou]

All, thanks for the explanations