“mystery Frequency”

[banginAltima]

If you tune it back to 40hz, I am thinking the box will peak out above the resonant frequency of the car. why are you going to tune it back to 40, when you are hitting better numbers with a lower tuning.

when the box was tuned to 40Hz, i only had two 4" ports. Now i have four 4" ports in it. There is no way of telling which freq is going to be better until i try it.

[roscoe1129]

The only way to tell would to build a box tuned to 40-42 hz and test it that way.

[01xtreme]

when the box was tuned to 40Hz, i only had two 4" ports. Now i have four 4" ports in it. There is no way of telling which freq is going to be better until i try it.

What would be the problem with pluggin 2 of the holes? it will let you get a ballpark idea, not to mention saving all the time building another box.

[banginAltima]

What would be the problem with pluggin 2 of the holes? it will let you get a ballpark idea, not to mention saving all the time building another box.

I am not going back to two ports. Rf spec is two 4" each. If any thing I want to try adding one more port making it 5 total. I am not sure what you mean about getting a ballpark idea.

[01xtreme]

I am not going back to two ports. Rf spec is two 4" each. If any thing I want to try adding one more port making it 5 total. I am not sure what you mean about getting a ballpark idea.

I misunderstood your comment. I though you said you were going o try and go back to a 40hz tuning and testing to see if it was louder. my bad...i will just go take my foot out of my mouth now. lol.

[Decaf]

well using the program i got

5.6cuft@32hz, peaks at ~45-46

5.6cuft@36hz, with ur setup, peaks at ~46.2hz

5.6cuft@35hz, peaks at ~46

rf suggests 38hz, which peaks at ~47.5

5.6cuft@40hz, peaks at ~48.9

so it seems the higher you tune the farther away ur peak is from your cars peak

and from 35-40hz tuning, theres only a gain of 1db(not including cabin gain)

id say add one more port so there's ~62 sqin port and id say tuning to 36-39 is going to be loud.

[banginAltima]

Another question: So if my cars freq is around 41 and this is giving me my best scores yet, why do a lot of people compete in the high 70's? Isn't that fighting against the cars freq?

[Decaf]

Another question: So if my cars freq is around 41 and this is giving me my best scores yet, why do a lot of people compete in the high 70's? Isn't that fighting against the cars freq?

who uses high 70's

i think its more like high 50's, low 60's

[galacticmonkey]

Extreme class cars burp usually 70hz+. Many burp right at 80hz.

The reason is.... Well, I dont know.

Extreme class doesnt really have any rules. Any rule you thought you knew about car audio doesnt exist in Extreme class. There is no rhyme or reason to the way things work. Its just those crazy bastards that compete in it actually figured it out!

[Decaf]

Extreme class cars burp usually 70hz+. Many burp right at 80hz.

The reason is.... Well, I dont know.

Extreme class doesnt really have any rules. Any rule you thought you knew about car audio doesnt exist in Extreme class. There is no rhyme or reason to the way things work. Its just those crazy bastards that compete in it actually figured it out!

well yeah, extreme does(hell 1/2 the car is concrete!), but everyday guys like us driving the cars we take to work... we burp much lower than extreme class since we usually have lower tune frequencys so we can play music

to answer more directly, different cars peak at different frequencies, but few people burb around 70hz unless they are into some serious competitions with lots of money