street max build on the CHEAP!!!

[n8skow 10+ year member]

?

What frequency are you playing?

On 2k - should be doing a much higher score from a wall...

Do the coils check out okay on those woofers?

well I ran it a couple times now that the box is finished. but I cant play it much since I dont have the battery and my volts are seriously dropping and it cut out once and shutdown the two amps.. and I dont want to cook them.. here's the clamped numbers and voltage. ..
A.C. amperage 20.51

A.C. voltage 102.4

D.C. voltage (starting 13.1 - dropping 11.2)

Impedance (starting 1.9 ohms - rising 4.99

Total RMS output 2100 watts

I have to try a few things to lower impedance rise but im seriously surprised this amp is putting out 2100 watts at 4.99 ohms strapped.. and surprised it's doing 147.5 db legal with 2100 watts.. it only gained .5 or so db sealing off the wall but it could be more and im just having voltage issues restricting me from seeing a higher output (due to testing it off a battery sitting on the garage floor)

anyways the wife is going out of town for the week.. and it just happens she's going be in the same city the xs power 3100 is! !

once I get that the system is completed .. well the street max cheap build anyways. . then I will be putting 10× the power with the stetsom 7k2d amps! !

 

[akadj 10+ year member]

?What frequency are you playing?

On 2k - should be doing a much higher score from a wall...

Do the coils check out okay on those woofers?

what numbers should i be looking for with 2k clamped.. i was thinking 152

i seriously didnt even get a chance to burp it more then 5 - 6 times. voltage drop was so severe when the amps shut down i knew i was playing with fire and risk smoking them so im waiting till friday when i get my new battery and alternator hooked up.

but.. when i did burp it i tried 60hz cuz thats the max in this class and got 147.5 db .. then i went to 50hz and was going to work my way up but i didnt even get 3 seconds worth and everything shutdown.

i have a few things i want to try out so bad but i gotta wait for this battery.. and i leave to go out of town for work again on monday //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif

 

[n8skow 10+ year member]

What is it tuned to on paper? Any idea what frequency the car likes?

Burp box, on 2k clamped - I'd expect a 151-153 with a more traditional SPL wall design (woofers on passenger side, port on driver side) with the vehicle sealed up, mic on dash.

Music tuning - probably 2-3 db under that.

With the port up top, probably subtract 1-1.5 db from these numbers though (149.5ish with your current setup).

Getting your electrical situation squared away, you'll probably see db or so gain without changing anything else. Then it's just working on your box and tuning from there =)

 

[akadj 10+ year member]

What is it tuned to on paper? Any idea what frequency the car likes?
Burp box, on 2k clamped - I'd expect a 151-153 with a more traditional SPL wall design (woofers on passenger side, port on driver side) with the vehicle sealed up, mic on dash.

Music tuning - probably 2-3 db under that.

With the port up top, probably subtract 1-1.5 db from these numbers though (149.5ish with your current setup).

Getting your electrical situation squared away, you'll probably see db or so gain without changing anything else. Then it's just working on your box and tuning from there =)

i did run through all the frequency tracks and unfortunately the lowest impedance was at 47/49 hz with a spl peak at 52/53 hz... so ive got to try and subtract some internal volume and then once ive taken as much as possible im going to shorten the port and try to raise the tuning closer to 60hz because thats my limit in this class.

 

[n8skow 10+ year member]

Do you know what your box is actually tuned to though? Trying to visualize here the gap between your tuning and actual peak frequency.

Get that electrical solid first - or all your testing is gonna be frustrating with inconsistencies.

=)

It will be a bit counter-intuitive if your not used to clamping power - but you should see a point where your score is increasing as you go up a frequency at a time, but your power (amperage) is decreasing. At some point, your amperage will reverse stop dropping, and start climbing as you get higher and higher - that area where the amperage was lowest is where your box is wanting to play. The trick is to get that frequency close to what the car likes.

 

[akadj 10+ year member]

Do you know what your box is actually tuned to though?.....
...that area where the amperage was lowest is where your box is wanting to play. The trick is to get that frequency close to what the car likes.

ya the box is tuned to 47/49 hz.

I'm trying to match the box frequency to what the car likes.. I had 3 peaks in the car.. the first one at 52hz second at 61hz third at 72hz.. I would imagine the first peak at 52 is only because the box is tuned so low.. the 72 seams right on track with relationship of drivers to the mic / the speed of sound and quarter wave equation

 

[n8skow 10+ year member]

What organization are you competing in?

That 60hz cap is gonna hurt a lot of your car likes 72hz...

ya the box is tuned to 47/49 hz.
I'm trying to match the box frequency to what the car likes.. I had 3 peaks in the car.. the first one at 52hz second at 61hz third at 72hz.. I would imagine the first peak at 52 is only because the box is tuned so low.. the 72 seams right on track with relationship of drivers to the mic / the speed of sound and quarter wave equation

 

[akadj 10+ year member]

What organization are you competing in?That 60hz caps is gonna hurt a lot of your car likes 72hz...

Db Drag Racing Street Max.. actually all street classes in the db drag racing are 60hz & under with a max of 15 volts... super street and high classes are 80hz & under with a max of 18 volts..

 

[sbarber82 10+ year member]

updates?

 

[akadj 10+ year member]

updates?

I was tweaking it a bit.. got up to 148.. still not happy.

Right now im out of town working again but next weekend im going to be cutting 8" of port length off and adding 100 square inch of area.

 

[akadj 10+ year member]

UPDATES! !

I've started on removing the port and adding an additional 100 square inches!!

 

[akadj 10+ year member]

 

[akadj 10+ year member]

I tested it the way it was in the last picture just to see what my max frequency was with zero port length and to get an idea of how long of a port to add..

73 hz was the peak slp which is way to high for this class so im gonna try adding 7.5" of port length and see if i can get back to 60hz

I went down 3 db at 60 hz but went up 3 db at 73 hz the way it is now

 

[akadj 10+ year member]

Added 7.5" inch of port and my peak is at 68hz.. gonna do a few more mods over the next few weeks

 

[sbarber82 10+ year member]

Whats new?