What hz should I burp?

[loganberry]

only real way to know is do a sweep at a set volume and see which frequency peaks highest and go from there, my box is tuned to 35hz, buy my burp frequency is 46hz.

[SPL2K]

only real way to know is do a sweep at a set volume and see which frequency peaks highest and go from there, my box is tuned to 35hz, buy my burp frequency is 46hz.

correct. And if you wanted to get max SPL and not care about music anymore then you would want to tune alot closer to the 46hz mark. (but I know you dont want to)

[Boon]

No i didnt say that. I said regardless of what you tune your enclosure to, ts not going to change the natural resonant frequency of your car.

Say you car peaks at 51hz. It doesnt matter if you tune your box to 25hz, 33hz, 40hz, or 73hz. 51hz will always be the loudest frequency in that car. (as long as all adjustments on the head unit and amp correspond with that).

Eh. What if you build a box that has an enormous spike at say, 35hz, then response rolls off tremendously. Like a 6th order tuned to spike or something along those lines. Then the box's response will outweigh the cars response and you'll get a different peak frequency...

You can't change the car's peak (well, deadening does, or displacing more air with a huge ass box, and in my experience the peak changes a coupla hz with higher spl) but if you're talking about the overall response of the car + system as a whole the peak can be anywhere, especially if the resonant frequency of the vehicle gives you a weak-ass increase in dB, like in a Toyota Hiace.

I dunno why I'm typing all this, I'm sure you're well aware of it already and were just simplifying your answer...

[OldsBoomer]

39 Hz is not to low because my car peaks at 37 so 39 is an easy possiblity

[SPL2K]

Eh. What if you build a box that has an enormous spike at say, 35hz, then response rolls off tremendously. Like a 6th order tuned to spike or something along those lines. Then the box's response will outweigh the cars response and you'll get a different peak frequency...

in my experience the peak changes a coupla hz with higher spl)

If you had an enclosure with an "enormous spike" at 35hz but the vehicles peak frequency was considerably higher that 35hz then the output would be pretty weak unless the windows were down or a door was open.

Yes, usually at higher volume your burp frequency will drop 1 or 2 cycles because of panel flexing and movement.

[Marlo Stanfield]

Next competition as mentioned just run the sweep and see what is the loudest. But just like Mr. Hughes said, if you really want a loud burp box then tune 3-6hz below whatever your resonant frequency might be. Might wanna consider a removable port setup, where you can swap a daily/burp port in and out.

[Boon]

If you had an enclosure with an "enormous spike" at 35hz but the vehicles peak frequency was considerably higher that 35hz then the output would be pretty weak unless the windows were down or a door was open.

This bit is what I'm kinda getting at... a Focus is fairly small, I would expect it to peak in the mid 50's or higher and it's possible that his box tuning is having more effect than the car's resonance.

Then again I think he said a 'trunk' box? Our Focus's don't have trunks over here but I suppose if it's a sedan Focus then yeah, that wouldn't be a terribly surprising peak

[audiofanaticz]

No i didnt say that. I said regardless of what you tune your enclosure to, ts not going to change the natural resonant frequency of your car.

Say you car peaks at 51hz. It doesnt matter if you tune your box to 25hz, 33hz, 40hz, or 73hz. 51hz will always be the loudest frequency in that car. (as long as all adjustments on the head unit and amp correspond with that).

Correct natural response.

But say a box tuned at 30hz is not going to be the loudest at 51hz when the box is not built to play that not at its most efficiency. Most likely you will be in the 36-38hz freq, even tho the car peaks at said 51.

Just because a vehicle is willing to play XXhz doesnt mean it will if the box wont play XXhz.

Now if you where wanting a said spl burp machine to play at your peak freq, we will say 51hz again, from what my boss and his buddy taught me since I was maybe 12-13 years old helping out on a extreme vehicle is you will want to tune slightly lower then the peak. so maybe 46-47ish hz.

When I got my setup going, I went thru from track 30 on db jams vol 10, all the way to track 70, giving a mid volume burp to find my loudest freq. I wrote each score down, then went back and did full volume burps. Playing in the 47hz range was quieter then on the meter then the 33-39hz range.

[mlstrass]

Correct natural response.

But say a box tuned at 30hz is not going to be the loudest at 51hz when the box is not built to play that not at its most efficiency. Most likely you will be in the 36-38hz freq, even tho the car peaks at said 51.

Just because a vehicle is willing to play XXhz doesnt mean it will if the box wont play XXhz.

Now if you where wanting a said spl burp machine to play at your peak freq, we will say 51hz again, from what my boss and his buddy taught me since I was maybe 12-13 years old helping out on a extreme vehicle is you will want to tune slightly lower then the peak. so maybe 46-47ish hz.

When I got my setup going, I went thru from track 30 on db jams vol 10, all the way to track 70, giving a mid volume burp to find my loudest freq. I wrote each score down, then went back and did full volume burps. Playing in the 47hz range was quieter then on the meter then the 33-39hz range.

If you have 60 seconds you can try 2-3 burps and give it 10 seconds in between. So try 39, 41, and maybe 43. Obviously a sweep would be your best bet, so if the show isn't crowded, see if you can give the guy $5-10 to let you do a sweep.

Is this the Springfield show on the 30th?

[Crump]

If you have 60 seconds you can try 2-3 burps and give it 10 seconds in between. So try 39, 41, and maybe 43. Obviously a sweep would be your best bet, so if the show isn't crowded, see if you can give the guy $5-10 to let you do a sweep.

Is this the Springfield show on the 30th?

I have been playing around with my tones and I think my best is 39 hz (like I peaked at previously) w/ my drivers door open, other than that all sealed up. And yeah this is the show on the 30th you wanna sit on my trunk? lol im trying to get all them pesky sound waves into my cabin. Btw I loved your little 7 second run. Burp 156.6 and be on your way. I love Car Audio. and another btw your car = http://www.stevemeadedesigns.com/board/public/style_emoticons/default/hairtrick.gif http://www.stevemeadedesigns.com/board/public/style_emoticons/default/hairtrick.gif

Edit: btw # 3, I'm the kid with the focus.