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Lucky
04-18-2004, 11:32 PM
Ok, i was wondering what is the relationship between the size of a sealed and ported box to SQ and SPL

pavengmike6
04-19-2004, 05:07 PM
That is a big question. But the basics are this. A sealed box will give you a tight good SQ. A ported box can vary depending on how you tune it. You must take into consideration a few things when building a box. Some cars have their own freq range in which they work best. You will not be able to tell this until you play around with different box's. Also you have to consider different speakers work better at differnet freq of tuned box's too. Some people like to tune their box in the mid to low 30's and some like them higher. (it is a personal taste).

The size of the box and the size of your port determine the freq your box will be tuned too. This will make a deeper louder base depending on how you tune it. If you get to big or to small on a sealed or ported box you speakers will be usless. But if you want a good tight SQ sound a sealed box is the way to go. If you want a heart stopping bass then you will need to port your box. I know this is not a lot of answers but it is the basics.

Puggsley456
04-19-2004, 05:28 PM
Some people like to tune their box in the mid to low 30's and some like them higher. (it is a personal taste).

So where would you rate 26hz? That s what the maker of my subs recommends?
Is that disigned for high spl?

tommyk90
04-19-2004, 05:32 PM
26 hz is designed for SQL. If you want pure SPL(no daily driving here) do 42-48. For the best mix 30-36 hz would be your best bet.

Puggsley456
04-20-2004, 06:53 PM
This may be a stupid question but.....Does the tuned frequency of a box mean that the frequency its tuned to is the optimal frequency(you should play) toget the most spl out of it? If ya know what I mean. :confused:

pavengmike6
04-20-2004, 07:07 PM
I do not know if you have ever heard a bass test CD. But to answer the question I think you are asking is YES. You box will have its best SQ/SPL at the freq in which it is tuned. It will still play different freqs but they will be louder/optimized at there tuned freq.

454Casull
04-20-2004, 07:13 PM
This may be a stupid question but.....Does the tuned frequency of a box mean that the frequency its tuned to is the optimal frequency(you should play) toget the most spl out of it? If ya know what I mean. :confused:
No, it just means that that is the lowest frequency you should run through the sub , because once you go below the tuning point, excursion goes up very quickly. The frequency that you tune to depends on your needs, and if that includes SQ, then cabin gain should be incorporated into the response function so that you don't get any peaks.

Play around with WinISD Pro from http://www.linearteam.dk/ to learn more about box tuning.

BTW, not all acoustic suspension (sealed) enclosures are the same. The transient response of the driver depends on the Q - 0.5 is optimally damped (i.e. minimum overshoot when the driver responds to an impulse), 0.707 is optimally flat (re: the driver's response), and the smaller the box, the higher the Q.

An image to clarify - Qtc effect (http://diyaudio.com/forums/attachment.php?s=&postid=88711)