1. ## F3 > Fb ?

Playin with BBP again. My current box is tuned to 32.81 hz. I was playing around with a new design, and I noticed on the new design, I came up with 29.88 hz. But on my current one, the F3 is 31.03 hz. On the new design, F3 is 30.17. Whats the advantage/dissadvantages of the -3 dB point being higher then tunin freq?

2. ## Re: F3 > Fb ?

I know this doesn't answer your original question, but two-decimal-point accuracy is unneeded and certainly won't occur in real life

Accuracy to 1Hz won't likely be audible...

3. ## Re: F3 > Fb ?

Originally Posted by JimJ
I know this doesn't answer your original question, but two-decimal-point accuracy is unneeded and certainly won't occur in real life

Accuracy to 1Hz won't likely be audible...
Haha, yea. I just gave exact to get the theory of it.

4. ## Re: F3 > Fb ?

Essentailly, the F3 point is the frequency rolloff point. You are down 3 decibels from the original from your baseline or reference level. Usually, this signifies that you are losing output from said system because the drop is going to be noticeable and your output is going to drop substantially. There is generally no problem with it being lower than your tuning freq (especially that close), but if you have a less low frequency speaker and your F3 is far higher, try making the box a bit bigger or fooling around with dimensions. You don't want to lose output before your speaker makes peak output.

5. ## Re: F3 > Fb ?

So, my new design is tuned to 29.33 hz. F3 is 30.18. So this is not a good thing, right?

Heres what i'm doing, so you get the idea. I want to modify my current box (without changing any exterior dimensions) by lengthing the port (and no other modifications). I want to be right around 30hz instead of 33hz. I want to have a little lower extension, but still have the extension above, like I do now.

6. ## Re: F3 > Fb ?

It really won't matter. You are less than a hz away, and you aren't going to get too much music below there judging by what you listen to.

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