SPL Dash vs. Port

[GregU 10+ year member]

On monday I'm going to meter my SE12. From experiance I think I should be doing a little more than what I am, although I am tuned pretty low(27hz) and on low wattage(500rms), but here's the thing, I'm peaking at around 40hz..... This is my first hatchback(Scion TC). My hatch was flexing so much I rigged up tie downs to hold it down, if it's held down too tight nothing sounds good, if it's held down not tight enough I loose my lows(30hz and under) but I gain at around 35hz and up. I'm pretty sure I'm having some issues caused by the car itself and sympathetic vibration. If I measure SPL at the port and at the dash taking the difference between the two, would that tell me if it's the car itself I'm having difficulties with or the sub/enclosure? In other words, purley an example, say I made 150db at the port and only 120db at the dash, wouldn't that tell me that there's an issue with the install/car and not the sub/enclosure?

Any help or ideas would be appriciated.

P.S. i know that it could be because I'm tuned so low, but please remember the actual question that I'm asking(In bold)//content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif If i had to guess I'd say I'm making about 130db at the headrest.

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[Supergumby5000 5,000+ posts]

On monday I'm going to meter my SE12. From experiance I think I should be doing a little more than what I am, although I am tuned pretty low(27hz) and on low wattage(500rms), but here's the thing, I'm peaking at around 40hz..... This is my first hatchback(Scion TC). My hatch was flexing so much I rigged up tie downs to hold it down, if it's held down too tight nothing sounds good, if it's held down not tight enough I loose my lows(30hz and under) but I gain at around 35hz and up. I'm pretty sure I'm having some issues caused by the car itself and sympathetic vibration. If I measure SPL at the port and at the dash taking the difference between the two, would that tell me if it's the car itself I'm having difficulties with or the sub/enclosure? In other words, purley an example, say I made 150db at the port and only 120db at the dash, wouldn't that tell me that there's an issue with the install/car and not the sub/enclosure?
Any help or ideas would be appriciated.

P.S. i know that it could be because I'm tuned so low, but please remember the actual question that I'm asking(In bold)//content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif If i had to guess I'd say I'm making about 130db at the headrest.

no.

 

[GregU 10+ year member]

What would be a way for me to tell? Trial and error? I can already tell this car is going to be a beyatch....

 

[bball09124 10+ year member]

What do you care about numbers for? With 500 watts it's obviously not an SPL setup. I could build a .5 cubic foot box with a 1" port and do 170 on the meter but the box would sound horrid and do a crappy number on the dash.

Whether your hatch is loose or tight shouldn't really matter on the meter anyways, half a db at most. The only way to determine what's louder is to test both of them.

 

[GregU 10+ year member]

What do you care about numbers for? With 500 watts it's obviously not an SPL setup. I could build a .5 cubic foot box with a 1" port and do 170 on the meter but the box would sound horrid and do a crappy number on the dash.

Good point.//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 

[GregU 10+ year member]

Whether your hatch is loose or tight shouldn't really matter on the meter anyways, half a db at most. The only way to determine what's louder is to test both of them.

With the windows up it makes a huge difference, with them down it's not so much of a difference. With it tighter it's not as loud with the windows up as it is with the hatch loose w/windows up.

 

[bball09124 10+ year member]

With the windows up it makes a huge difference, with them down it's not so much of a difference. With it tighter it's not as loud with the windows up as it is with the hatch loose w/windows up.

That's all to your ear. It could be (and probably is) completely different on the meter.

 

[thorshammer1 10+ year member]

With the windows up it makes a huge difference, with them down it's not so much of a difference. With it tighter it's not as loud with the windows up as it is with the hatch loose w/windows up.

Makes me wonder if your confusing vibration for DBZZZZZZZZZZ!//content.invisioncic.com/y282845/emoticons/eek.gif.771b7a90cf45cabdc554ff1121c21c4a.gif