Box tuned to 34hz, peaks 38?

[purplesyrup]

sorry for being an ass what are the external dimensions on your enclosure please specify if you're using double baffle on any part of the enclosure

[purplesyrup]

and theexact dimensions of your port

[Shigshwa]

I... don't get why you guys are hammering me over 4 cu ft for my sub. it's not little for a 15 in my opinion. Here are my specs, I have the front wall double baffled.

My amp is a 3.5k in case you needed to know.

[Joe X]

WinISD can't predict response inside a car, it predicts response of an unbounded environment like outdoors or an anechoic chamber (for speaker testing).

[Shigshwa]

Right, but my concern is unloading right now. I know that unloading isn't immediate, but if it were to unload at a higher frequency like 38 hz, then playing 30hz would send me into the danger zone prematurely.

[Joe X]

The port will start releasing the load on the sub below (and above) tuning regardless of the response you have inside the car, you should bear in mind that in that program you have available an excursion plot to roughly find about that. Box layout can affect expected port loading if somehow sub and port do interact with each other, also you real tuning can be affected by a number of things the program can't factor in, port end clearances, etc.

Also the Torres calculator version you are using somewhat miscalculates slot port displacement, that version will usually show a larger net volume than there really is an as a consequence it shows a lower tuning than proper calculations would show, in my own testing that difference can be up to nearly 3 Hz in few cases.

[Shigshwa]

I see, interesting. How do we find out the actual tuning frequency of the box then? As in, can I measure it?

[twisted1]

i dont understand why some people will just try to chew up a fellow member when they ask questions about things they arnt really familiar with......wheres the damn love people?!

my boxes are usually tuned to 32hz to play on music but my truck peaks around 38. yes i can build a box to 38 an hit higher numbers, but i rather just be happy with good sounding bass to music

[bkolfo4]

purplesyrup needs to lay off the purple syrup.

To answer the OP question - Tuning frequency/box peak frequecy is not always going to be the peak of the system in the car. The vehicle resonant frequency will more than likely have more effect on the highest SPL than the box peak.

The sub will unload based on the port tuning, not your peak SPL frequency.

[Shigshwa]

I measured the impedance of the box while playing different frequencies, and there is a rise/slow oscillation around 34-35 hz.