Testing results???
02-10-2005, 10:09 AM
#1
1000 Watt CAFz'r
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Join Date: Jan 2005
Posts: 1,151
Last night I modded a previous box to fit one 12. It's a moddified crx box approx. 2.8 cu.ft. net tuned to 42 hz. After playing with the gains, and trying to get the most out of the 500w/rms sub, I found two interesting things.
1) I have two peaks: 46hz and 48hz
They both hit the exact same number on my TL, 145.0. Every other frequncy around those lost, even 47hz.
Q: What does this mean?
2) The more power I gave the sub, I started losing in output.
Q: Why would this happen?
Any help would be great [img]graemlins/thumb.gif[/img]
1) I have two peaks: 46hz and 48hz
They both hit the exact same number on my TL, 145.0. Every other frequncy around those lost, even 47hz.
Q: What does this mean?
2) The more power I gave the sub, I started losing in output.
Q: Why would this happen?
Any help would be great [img]graemlins/thumb.gif[/img]
02-10-2005, 01:35 PM
#2
1000 Watt CAFz'r
Join Date: Mar 2004
Posts: 1,093
ok.. you should have 2 peaks like that..
although they seem kinda low.. 1st peak would be the peak spl of your box, and the second in the peak spl freq of thre car.. but my guess is that your box is tuned to low for your car res freq, so you have also brought the car's res freq down maybe by a few hz.
i would try to tune that box around 45-46, then you should see peaks in the 49-52hz range. this should also increase spl output, as it's a more effecient freq to play at, and closer to the vehicle res freq.
sorry i can't elaborate on that answer right now, but i'm ina rush
i wil help u again later!
BTW.. more power to the woofer, what do u mean? another amp, or turning up gains?
if u add another amp and it looses db's, make sure amps are both set correctly(blanaced outputs), and keep close eye on voltage drops, as the less power to the amps, the less power out of the amps
if your just turning up your amp, you maybe clipping the signal, or putting out to much distortion to the woofer, also voltage drop can efffect just 1 amp
Livin Loud
although they seem kinda low.. 1st peak would be the peak spl of your box, and the second in the peak spl freq of thre car.. but my guess is that your box is tuned to low for your car res freq, so you have also brought the car's res freq down maybe by a few hz.
i would try to tune that box around 45-46, then you should see peaks in the 49-52hz range. this should also increase spl output, as it's a more effecient freq to play at, and closer to the vehicle res freq.
sorry i can't elaborate on that answer right now, but i'm ina rush
i wil help u again later!BTW.. more power to the woofer, what do u mean? another amp, or turning up gains?
if u add another amp and it looses db's, make sure amps are both set correctly(blanaced outputs), and keep close eye on voltage drops, as the less power to the amps, the less power out of the amps
if your just turning up your amp, you maybe clipping the signal, or putting out to much distortion to the woofer, also voltage drop can efffect just 1 amp
Livin Loud
02-10-2005, 02:09 PM
#3
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I'll try to tune the box a bit higher and see what happens.
As for the power, I slowly turned up the gains on one amp (bout 1/4 turn at a time) and done the same for both. Btw, they are strappable amps so don't need to balance output. I noticed that to a certain point the output(db's) started dropping.
I guess the sub could only take so much.
Ohh well
As for the power, I slowly turned up the gains on one amp (bout 1/4 turn at a time) and done the same for both. Btw, they are strappable amps so don't need to balance output. I noticed that to a certain point the output(db's) started dropping.
I guess the sub could only take so much.
Ohh well
02-10-2005, 08:22 PM
#4
ok in yor jetta you will find that 49-52 hz is the best frequency to use... you will also find what I have found ..that the TL needs to receive CLEAN signal not a clipped signal to measure the highest SPL... hope this helps
to tune higher make the port slightly bigger and the box a litt;e smaller..maybe just put angles into it to take up the airspace and leave the ports exactly the way they are
good luck..and lemme know if this helped
to tune higher make the port slightly bigger and the box a litt;e smaller..maybe just put angles into it to take up the airspace and leave the ports exactly the way they are
good luck..and lemme know if this helped
02-11-2005, 07:36 AM
#8
gotta be carefull tho...Ive fallen into a trapped situation before that shortening the port made the box bigger and even tho the port was shorter still tuned the box to the same frequency...and lengthening the port still tuned the same because you were taking away from box volume so a longer port length was required...its a draw..best was to change port area while keeping box volume the same or decrease actual box volume and keep the port are the same... dont do both at the same time unless totally neccessary
btw..what is your port size(s) and length and sub displacement in that 2.8 cu.ft box?
[ February 11, 2005, 08:38 AM: Message edited by: MTA ]
btw..what is your port size(s) and length and sub displacement in that 2.8 cu.ft box?
[ February 11, 2005, 08:38 AM: Message edited by: MTA ]
02-11-2005, 09:27 AM
#9
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Join Date: Jan 2005
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^^^^ Got 2 4" aeroports outside the box and had to calculate the sub displacement.
I think i will try to take up space in the box.
Does rounding out corners work? If so, I think i could take up space that way. Any opinions on that.
I think i will try to take up space in the box.
Does rounding out corners work? If so, I think i could take up space that way. Any opinions on that.
02-11-2005, 09:42 AM
#10
1000 Watt CAFz'r
Join Date: Mar 2004
Posts: 1,093
well sence u have your ports ouside of the box, that's even easier for tuning you can just shorten/lenghten them! that way you don't effect the box size at all! also i would try adding a port to each box... you never know, i have had good/not so good results from both ways!
as for rounding corners, i would do it. i have usually gained som spl for it! it helps eliminate dead waves in the corners and stuff.
also try to do some fiberglass resin in your box! i have gained spl EVERY time i have done it, and that was like 30-40 boxes i have done..LOL
Livin loud
you can just shorten/lenghten them! that way you don't effect the box size at all! also i would try adding a port to each box... you never know, i have had good/not so good results from both ways!as for rounding corners, i would do it. i have usually gained som spl for it! it helps eliminate dead waves in the corners and stuff.
also try to do some fiberglass resin in your box!
i have gained spl EVERY time i have done it, and that was like 30-40 boxes i have done..LOLLivin loud
