Right know I hit decent spl# with my current box, which is tuned to 37hz, I called the manufacture and they gave me specs on a new spl box but they told me most people with my equipment tune to 50-55hz! I had a test done, between 42 and 47hz it was the loundest with a 44hz peak. However, I never went past 47hz because it started to lose db's! What should I do? retest! or tune to their recommended 50hz? This box they recommend is much bigger then the box I tested at to begin with.

Thanks
David

pm me man

this site has a formula that works for me
http://www.jlaudio.com/tutorials/ports/index.html

Its not the formula for the port that I'm having problems with. I dont know what to tune the port to 40hz? 45hz? 50hz?

It all depends on the car.. the only way to find out is to test [img]graemlins/thumb.gif[/img]

Alright lets say my car gets the most response at 44hz! What should I tune the port at?
The size box they want me to make is like 7.25cf, made out of inch thick mdf, I cant afford to make 4 or 5 of these boxes even though I know testing is my best bet. I just want to think everthying through so I get as close on the first try.

Thanks
David

[ July 15, 2005, 11:35 AM: Message edited by: dchow ]

tune 7hz below peak. u dont need a 7 cube box for 1 12. 3 cubes is more than enough

^ 7hz? Always? Regardless of what the frequency is?

I'm not knee deep in the SPL world so I'm not disputing you - just seems kind of odd. If you look at it from a box point of view, one would tune 1/2 an octave below the resonant peak, so in this case 33Hz. Admittedly, that seems low for an SPL box but then 44Hz is kind of a low resonance too - must be a large vehicle.

Must be a case of the real world and theory not quite lining up [img]graemlins/dunno.gif[/img]

The "7hz rule" is more just a guideline of where to start. Any SPL box design really needs to be tested at a few freq's to find out which suits best. [img]graemlins/thumb.gif[/img]

this is exactly why this topic is in the SPL section... and Prolifik knows SPL. If he said that throwing subs off a brigde would gain spl, I would prolly believe him and then ask him which brigde as the biggest gain