Ported sub design-little improvements towards perfection

[audfrknaveen]

Hi All,

I built a few ported subs with basic design calculations.
Now I am looking towards little betterment in design.
Please help me with minor queries ....

Question1 please see the attached GRAPH1.
Does a 3dB peak near roll off really make the sub sound boomy?
Is the difference clearly noticeable? Or is it negligible?

Question2: Please see attached GRAPH2
Ideally, F3 should be lower than box tuning frequency.
But if F3 is 3 to 6dB higher than box tuning frequency, what happens?
For example,.... box is tuned to 30Hz but F3 is at 36hZ

A)does the sub sound boomy even though the roll off is smooth without any peak? Or...

B)Sub sounds tight, but the only drawback is we hear box tuning freq of 30Hz at 6dB quiter

Thanks in advance...

 

[Sonce]

1.) 3 dB peak = boomy, especially if Qts is high/moderate.
2.) Perfect!
Ideally, F3 should be HIGHER than box tuning frequency!
A) No
b) Yes (it is not a drawback, just normal way how things work)

Be sure to measure TS parameters yourself, do not trust datasheet numbers!

 

[audfrknaveen]

Wow.....I was struggling to achieve F3 lower than box frequency !!!

So I don't have to worry too much about it As long as the graph has smooth rolloff without a peak.

Thanks for the information Sonce !!
(I will try to make F3 close to box tuning any way.... )