Amplitude Responce and tone questions

[jntar 15]

This passed weekends comp got me thinking.

In BBP6 and WinISD the F3 for my NAR (Amplitude Responce) is 50.8hz, so at the comp I expected somewhere over that to be my "loudest" tone. When I did the sweep, why was 37hz? Could it have to do with the cabin of my truck?

Next question, the New SI's F3 per BBP6 is 29.73@1.5 cu.ft. Wouls the "loudest be even lower then before or again does the "resonant frequency" set around 37 for the "loudest" tone.

I am at a loss. My knowledge of these things is very limited and I always want to learn more

[Scarenius 0]

There are so many things affecting what your top frequency is. Everything from barometric pressure to how much deadener in your vehicle to how much it weighs to temperature and humidity to elevation, etc. It's air pressure, and very sensitive to just about everything.

Seeing as your truck is fairly new, I'm going to say it's been nicely deadened from the start. That along with it being a regular cab picked (Small, rigid cabin) would successfully drop the peak frequency.

That's a very nice number to compete with.

[Tirefryr 1,742]

Don't rely on BB6 or winISD for anything more than enclosure dims, cuts, and vents.

[EFFENDI 0]

^ x2

[Nikuk 1]

Don't rely on BB6 or winISD for anything more than enclosure dims, cuts, and vents.

<{POST_SNAPBACK}>

+1 x^a billion.

get on a TL and burp a sweep at near full volume. You'll know exactly where your loudest harmonic is.

also, loudest frequency to the dash is DIFFERENT from loudest frequency in the kick.

other then that, whatcha wanna learn?

[jntar 15]

Don't rely on BB6 or winISD for anything more than enclosure dims, cuts, and vents.

<{POST_SNAPBACK}>

+1 x^a billion.

get on a TL and burp a sweep at near full volume. You'll know exactly where your loudest harmonic is.

also, loudest frequency to the dash is DIFFERENT from loudest frequency in the kick.

other then that, whatcha wanna learn?

<{POST_SNAPBACK}>

Here is one.

Current system is in a small sealed box, smaller then manufacturs specs. Again in the kick the freq was 37hz. Why is that? I would think that it would be higher. Could the smaller cabin of my truck have anything to do with it?

EDIT: better yet...what are the main factors that determine your peak frequency?

[req 0]

EDIT:  better yet...what are the main factors that determine your peak frequency?

cabin size

box size

port tuning

speaker

reflections(windows, bare metal, ect)\absorbing surfaces (cloth, ect)

flexing (cabin and box)

box placement

direction port\sub face in the cabin

trunk\suv\hatchback

there are ALOT of factors. get on a TL, like nick said - burp a sweep, and find your best harmonic (sealed box is a good way to do this). rule of thumb, tune your ported box (for SPL of course) to about an octave below that harmonic. some people say 10hz. this is what testing is for.

keep playing with box placement, sub directions\port directions, box size, port size\tuning, mass loading, and all the stuff you CAN change. and see if anything you do gets you higher scores. and keep going from there.

but ive never done this stuff. so i cant really help you anymore than that :

[jntar 15]

EDIT: