Hello!
There is something strange in your group delay result.
I simulated your speaker (Blue) together with my own speaker (Red), which has, by coincidence, same volume (80 liters) but with an 8" woofer.
This is what I use to listen at home for many years and I think it sounds great.
The group delay I see is much lower than yours and in my result it looks reasonable (<16ms) above 30Hz for both speakers.
These are the T/S parameters I took from SB website
There is something strange in your group delay result.
I simulated your speaker (Blue) together with my own speaker (Red), which has, by coincidence, same volume (80 liters) but with an 8" woofer.
This is what I use to listen at home for many years and I think it sounds great.
The group delay I see is much lower than yours and in my result it looks reasonable (<16ms) above 30Hz for both speakers.
These are the T/S parameters I took from SB website
Oh I see. Indeed, if you add this high pass, it changes the group delay.
From the point of view of the loudspeaker itself, I think the result is quite good.
Nice frequency response (25Hz@-3dB), low air velocity, good group delay.
It will sound pretty good!
Just pay attention on the port resonance, which is a bit low around 300hz, if you plan to use this frequency in the woofer (depends on the crossover frequency you plan to use).
If you use a 3" round port, you still get reasonable port velocity (31m/s at 30Hz/200W) and resonance goes to 720Hz.
Someone may say this air velocity is too high, but in generic music program, you don't have 200W in 30Hz, so this air velocity will never be achieved, unless you listen to very specific music. I listen to music with lots of bass, most my projects got air velocity in that region and I don't hear any port noise.
Another option is to decrease a bit the square port to 340mm x 20mm - Resonance goes up to 460Hz and air velocity at 30Hz /200W goes down to 21m/s.
I don't have much experience with square ports, so I cannot comment about other issues.
I have more experience with 2" and 3" port diameters in my projects.
From the point of view of the loudspeaker itself, I think the result is quite good.
Nice frequency response (25Hz@-3dB), low air velocity, good group delay.
It will sound pretty good!
Just pay attention on the port resonance, which is a bit low around 300hz, if you plan to use this frequency in the woofer (depends on the crossover frequency you plan to use).
If you use a 3" round port, you still get reasonable port velocity (31m/s at 30Hz/200W) and resonance goes to 720Hz.
Someone may say this air velocity is too high, but in generic music program, you don't have 200W in 30Hz, so this air velocity will never be achieved, unless you listen to very specific music. I listen to music with lots of bass, most my projects got air velocity in that region and I don't hear any port noise.
Another option is to decrease a bit the square port to 340mm x 20mm - Resonance goes up to 460Hz and air velocity at 30Hz /200W goes down to 21m/s.
I don't have much experience with square ports, so I cannot comment about other issues.
I have more experience with 2" and 3" port diameters in my projects.
No , this subwoofer will go max to 80hz.
It will mainly be used for home theater, and very little for music. Even when used for music, it will have a different preset and will play from 20 to 40-50Hz.
can you tell something about first port resosnance, please. I am not familiar with this...
Hi, so in this case there is no problem.
The port, depending on the area and length, will resonate at a certain frequency like a pipe or a whistle.
The term "first" is just to mention the first frequency, as it will have upper harmonics too.
So if you excite this port at that frequency, you create a bump in the frequency response which is not desirable at all.
The way to avoid this is to set the port resonance to be higher than the highest frequency that will be playing inside the enclosure.
In your example, you will limit the upper frequencies in the enclosure to 80Hz, so the port will never be excited on its resonance frequency (296Hz).
On the other hand, if this was a 3-way speaker and the crossover frequency between woofer and mid would be 500Hz, you would excite the port and the result wouldn't be good.
The port, depending on the area and length, will resonate at a certain frequency like a pipe or a whistle.
The term "first" is just to mention the first frequency, as it will have upper harmonics too.
So if you excite this port at that frequency, you create a bump in the frequency response which is not desirable at all.
The way to avoid this is to set the port resonance to be higher than the highest frequency that will be playing inside the enclosure.
In your example, you will limit the upper frequencies in the enclosure to 80Hz, so the port will never be excited on its resonance frequency (296Hz).
On the other hand, if this was a 3-way speaker and the crossover frequency between woofer and mid would be 500Hz, you would excite the port and the result wouldn't be good.