1995 Chevy Silverado Extended Cab
Subwoofer: 15" RE XXX
Amplifier: PA 3000dB
Enclosure: 8cu Ft ported to 35hz, peak at 41hz
SPL @ 41hz (officiall): 144.7
Overall standing in the Competition: 3rd in class (Stock 2)
Competition Layout: Very Similar to SLAP
2nd place hit 145db Even, lost by .3dB, just goes to show
how much every little bit counts
Not to bad for the 1st run, time to start modifying and testing new enclosures, ill post pics from the show when i get them developed, There was a VW rabbit hitting 168.8dB and didnt have it turned up all the way either, that was nutz
-PL
Replies (10)
ssallstar598 on 04/4/2005 01:25:42
WOOOOOOOOOOW whats your setup? and the VW rabbit
awesome job on placing
P0werLifter on 04/4/2005 03:02:06
Thanks, as far as the setup in my truck I have it listed above in my 1st post, the exteded cab portion is all speaker enclosure up to the bottom of the window with the Sub and port facing up.
The VW rabbit was using two Atomic 18's in a wall. Not sure of the wattage but i know he was running 17 batteries, thats right..u read it correct,, 17 batteries so u know he's pumpin HUGE wattage.
ssallstar598 on 04/4/2005 03:08:47
can you tell me the brands (im not good at identifying by models/model numbers)
17 batteries?!?!? thats nuts... how does he fit them all into a lil VW?
Victor on 04/4/2005 04:28:12
Hey PL,, those are great numbers for a beginning...
I am sure u must have already tried and analysed the reasons u fell back by a 0.3db..
anyways here's what i think u can do to further improve the performance..
1 - some more sound deadning the metal of you car.
2 - Changing the rubber parts at the joints from where air pressure can leak.
3 - Try and use the interiors material which is more absorbtive then reflective.Try and eliminate as many reflective surfaces as possible.
4 - Aim the sub at 45degrees up facing the back of the trunk.This is not a thumb rule but for most of the cases this holds true and gives better bass reinforcement.
5 - Try designing a 4th orderbandpass, which is tuned at 40Hz to 65Hz or somewhere near to that passband. A properly designed Bandpass can net 3-6db more then a ported box.
6 - Again here If you look at some hornloaded bandpass designs they are known to display even a better rise in SPL then the regular 4th order bandpass.It wud be extremely time consuming and hard to make a horn loaded bandpass enclosure.. but if u are successful you can gain more than 10db's for sure..
7 - the reason why these are not extensively used is because of the poor transient response, but if your aim is netting higher SPL then this wud be the best deal.
8 - Dont know about ur electrical upgrades but even if your power supply falls weak your system wont be able to be at its best.
lemme know if you need some help with the enclosure designing..
Best of luck.
Victor..
lessismorespl on 04/4/2005 08:16:05
Nice place P.L. Those RE XXX's are insane subs, I'm thinking on going w/ 2 RE MT 12's and 2 Diamond Audio D51200.1's. RE is really making a name for themselves. shame you lost out by such a small percentage, I know how it feels, I missed 1st place once by .1 dB, the next day I change how my enclosure was aimed and tested it, and got a gain of 1.6 dB's, so then I felt really bad.
Very good suggestions victor. Even though I have been doing this for years, I truly enjoy getting suggestions now & then b/c I love car audio and installing. Sometimes an idea actually works, people thought I was crazy when I said I was gonna port my rear deck, now everyone wants advice on how to figure the calculations so they can do it, people thought I was stupid for spending money on sound dampening, now they ask my advice on what is good and what is not. We tested my car before ports, and after, I got a 4.7 dB gain, the sound dampening not only improved the sound, but gave me a minor gain of 1.3 dB's, which seems insignificant, but those of us experienced in competition know that even a few percentages can make the difference between going home w/ a trophy, or going home w/ some free manufacturer t-shirts and hats.
Definately follow victor's advice on aiming the enclosure, and the sound dampening may not be a bad idea either.
Victor on 04/4/2005 09:14:48
Hey lessismorespl,... when tego did that porting i was really opposing that .. not in the basics but without calculations wud be a big mess.. luckyly he got it right..
one more thing..
of what i understand of enclosures, porting the trunk does this..
1 - sealed enclosure -
here the sealed enclosure acts as a rear chamber and the trunk as the front chamber. and the ports open up into the listening area.. .. so basically it becomes an untuned 4th order Bandpass enclosure ( if the calculations for chamber and port tuning are not done )
2 - Ported enclosure - here the ported enclosure acts as a rear chamber, which is ported ( thru a tuned port ) into the trunk which can be considered as the front chamber, the trunk is then ported into the listening area, which makes this system a 6th order Bandpass.
A 6th order bandpass is known for really bad transient responses and can also unload a sub if not designed properly.
So as far as i understand , porting the trunk wud work much better in case of a sealed enclosure rather than a ported one..
Also , both the 4th and the 6th order Bandpass systems are known for netting higher SPL at the tuning frequency , so no wonder you get an acoustical raise of a couple of DB's.
and in all the ways you definitely need to consider the front chamber ( trunk volume ) calculations and the port tuning, if u dont do that, then u have to be plain lucky to get expected good results..
Thats what i understand of it..correct me if i am wrong anywhere..
Victor...
lessismorespl on 04/4/2005 10:07:09
You are exactly correct. I did not just say "hey, I'm gonna cut a couple holes in my rear deck and port the trunk." We took into account the volume of the trunk, where the enclosure was going to be placed and how it was going to be aimed, the volume of the cabin and what direction to aim the ports, we also did several calculations on where to place the ports for the best possible gain vs response. That is why, if you look at my pics on carstereo.com, the ports are about 5" apart in the center of my rear deck. If it was just a cosmetic thing, I'm sure I would have found a place to put them that looked much better than where I placed them, but in all my calculations, that was the best place to get not only the best gain, but to also get the best response. Another thing that has to be considered is sound dampening, if the trunk is not sealed and dampened properly, then the port will do nothing more than let more road noise into the cabin of the vehicle, so before I even considered porting the rear deck, I used 40 sq ft of sound dampening to make sure my trunk was free of road noise, in some places we used 2 layers, and we did the rear deck top & bottom w/ 2 layers, all together just in the rear deck and trunk there is easily 50+ sq ft of sound dampening. Aiming the enclosure is very important also, you can have the ports perfectly placed and the calaculations just right, (in my case 5" apart, 6" long), but if you do not figure in how the enclosure is aimed, you will get horrible SQ, much like how subs sound when they are on display or when you open your trunk, you get that sloppy muddy sound, so I used velcro to secure my enclosure down so it does not move out of place. installer.com was very helpful when it came to aiming the enclosure. I also did some minor inexspensive work to secure the outside of the car better: replaced the cheap factory plastic clips on the bumper cover w/ bolts and teflon lock nuts, secured sound dampening strips in between the bumper cover and the metal where I could get to it, used that $3 expanding foam where I could not get to. As for sound dampening, I need to do the front doors still, and would like to get to the floor boards in the front. The rear floor boards and doors are already done. Basically, if a person does not take the time to calculate several variables in SQ vs SPL when porting the trunk, you will end up w/ a huge mess and the best subs in the world would not sound good. Another thing I almost forget to mention, you also have to calculate the rear stage speakers, I used baffles and sound dampening there so they did not interfere w/ the sound coming through the ports, if you leave them open as is the case w/ most rear stage speakers, they will cause major port noise, kind of a whistling sound. I would not suggest porting the trunk unless you have vast experience in building enclosures, and are either a professional or have vast experience in car audio and know every angle and variable to do it right. Basically, your trunk is a secondary enclosure, so in altering anything within the trunk area, you must take the same vaiables as you do when building an enclosure into consideration.
MrBrownstone on 04/4/2005 13:03:51
Tuned to 35 Hz? What are you trying to do? kill your speakers?!!?!? Or is it a 'requirement' to play 41Hz through your system?
Wanna hit mid 150s? try 55 to 70Hz. More cabin gain. Vented @ 45 to 55 HZ should result in the proper box gain and combine with the cabin of the truck.
Please explain the rules of SLAP to me, because I'm used to DB DRAG. I hit 148.6 with 2 Audiobahn AW1200 and a 200Wx2 Audiobahn Amp in 2000. Super Street.
P0werLifter on 04/4/2005 14:17:37
Good replies so far. Please Keep in mind that I am currently competing with an Extended cab truck and the gains are different than a CRX or a car in that sense. Also bear in mind that currently the truck is not setup for pure SPL, this is an SQL setup for the time being but I'm going to start designing an SPL setup i can put in for competitions.
For the new enclosure type, im thinking about going with a Horn/Transmission Line enclosure to really maximize the gains out of the woofer. I'm also probably going to be purchasing a Digital Designs (DD) 9915 or an RE 18" MT. The only reason I might not go with the MT is talking to my good buddy who has been competing for a while and is on a team told me that they are very sensitive to the setup, if you get anything off what its supposed to be the setup will sound like crap. (At the show, with 1 12" MT he hit a 154.6dB with one Treo Amp in a CRX).
The other wierd thing is, with my enclosure tuned to 35hz, it peaks at 41 any higher and i loose my gain, I know, ive tested it lol but I'm taking out the enclosure within the month to build a sealed enclosure to really sit down and test the resonant frequency of the cab. Inside the cab I have 200sq feet of soundeadedning material.
Good advice victor, ive done most of it already but I do believe its time to change the gaskets on the windows, especially the back side windows because i KNOW im loosing SPL out of them. I had to replace one b4 the show due to it popping out whenever the bass hit.
The 1st thing on my list other than the new enclosure is more / better amplifiers. I can get Crossfire amplifiers that are fully modded at cost through my friend along with competitors prices on RE, Crossfire and some others.
List In order of purchase/manufacture
1. New Enclosure
2. Term Lab Sensor for testing at the house
3. New Amplifiers
4. New Woofer
5. New Automobile, most likely a CRX or similar hatchback
for SLAP rules go to SlapShow.com I believe is the layout. Classes are grouped by woofer Square inches.
Victor on 04/4/2005 15:29:18
hey PL i got a nice Horn loaded design to share with you.. will have to make a few changes tho cause this design was basically meant for 2 x 8"'s and 2 x 10"'s but can work out for 2 x 12"'s.
You may not need to have a 15" or a 18" sub to loose on SQ.. Instead 2 brahma or RE XXX 12" wud do wonders.. i can bet that any 2 of those in this enclosure will give you 160+ db even on its worst day ...
I had made one with 2 blau 10" velocity series 400wrms subs with an alpine MRD-1000 and they scored a whooping 143.07 db, which is unnatural for such subs to reach.
here is the over view and the construction for 8"s and 10"s if you are interested then we can together formulate for the 12" subs...THINK
OVERVIEW
http://www.decware.com/whorn.htm
CONSTRUCTION
http://www.decware.com/whornok.htm
FORUM specially dedicated to this enclosure ( surprised..eh..!!!)
http://www.decware.com/forums/Wicked/
Here's a post for modifications to be done for 12" subs..
http://decware.com/forums/Wicked/posts/882.html
Hope that helps..SMILE
Victor...
Subwoofer: 15" RE XXX
Amplifier: PA 3000dB
Enclosure: 8cu Ft ported to 35hz, peak at 41hz
SPL @ 41hz (officiall): 144.7
Overall standing in the Competition: 3rd in class (Stock 2)
Competition Layout: Very Similar to SLAP
2nd place hit 145db Even, lost by .3dB, just goes to show
how much every little bit counts
Not to bad for the 1st run, time to start modifying and testing new enclosures, ill post pics from the show when i get them developed, There was a VW rabbit hitting 168.8dB and didnt have it turned up all the way either, that was nutz
-PL
Replies (10)
ssallstar598 on 04/4/2005 01:25:42
WOOOOOOOOOOW whats your setup? and the VW rabbit
awesome job on placing
P0werLifter on 04/4/2005 03:02:06
Thanks, as far as the setup in my truck I have it listed above in my 1st post, the exteded cab portion is all speaker enclosure up to the bottom of the window with the Sub and port facing up.
The VW rabbit was using two Atomic 18's in a wall. Not sure of the wattage but i know he was running 17 batteries, thats right..u read it correct,, 17 batteries so u know he's pumpin HUGE wattage.
ssallstar598 on 04/4/2005 03:08:47
can you tell me the brands (im not good at identifying by models/model numbers)
17 batteries?!?!? thats nuts... how does he fit them all into a lil VW?
Victor on 04/4/2005 04:28:12
Hey PL,, those are great numbers for a beginning...
I am sure u must have already tried and analysed the reasons u fell back by a 0.3db..
anyways here's what i think u can do to further improve the performance..
1 - some more sound deadning the metal of you car.
2 - Changing the rubber parts at the joints from where air pressure can leak.
3 - Try and use the interiors material which is more absorbtive then reflective.Try and eliminate as many reflective surfaces as possible.
4 - Aim the sub at 45degrees up facing the back of the trunk.This is not a thumb rule but for most of the cases this holds true and gives better bass reinforcement.
5 - Try designing a 4th orderbandpass, which is tuned at 40Hz to 65Hz or somewhere near to that passband. A properly designed Bandpass can net 3-6db more then a ported box.
6 - Again here If you look at some hornloaded bandpass designs they are known to display even a better rise in SPL then the regular 4th order bandpass.It wud be extremely time consuming and hard to make a horn loaded bandpass enclosure.. but if u are successful you can gain more than 10db's for sure..
7 - the reason why these are not extensively used is because of the poor transient response, but if your aim is netting higher SPL then this wud be the best deal.
8 - Dont know about ur electrical upgrades but even if your power supply falls weak your system wont be able to be at its best.
lemme know if you need some help with the enclosure designing..
Best of luck.
Victor..
lessismorespl on 04/4/2005 08:16:05
Nice place P.L. Those RE XXX's are insane subs, I'm thinking on going w/ 2 RE MT 12's and 2 Diamond Audio D51200.1's. RE is really making a name for themselves. shame you lost out by such a small percentage, I know how it feels, I missed 1st place once by .1 dB, the next day I change how my enclosure was aimed and tested it, and got a gain of 1.6 dB's, so then I felt really bad.
Very good suggestions victor. Even though I have been doing this for years, I truly enjoy getting suggestions now & then b/c I love car audio and installing. Sometimes an idea actually works, people thought I was crazy when I said I was gonna port my rear deck, now everyone wants advice on how to figure the calculations so they can do it, people thought I was stupid for spending money on sound dampening, now they ask my advice on what is good and what is not. We tested my car before ports, and after, I got a 4.7 dB gain, the sound dampening not only improved the sound, but gave me a minor gain of 1.3 dB's, which seems insignificant, but those of us experienced in competition know that even a few percentages can make the difference between going home w/ a trophy, or going home w/ some free manufacturer t-shirts and hats.
Definately follow victor's advice on aiming the enclosure, and the sound dampening may not be a bad idea either.
Victor on 04/4/2005 09:14:48
Hey lessismorespl,... when tego did that porting i was really opposing that .. not in the basics but without calculations wud be a big mess.. luckyly he got it right..
one more thing..
of what i understand of enclosures, porting the trunk does this..
1 - sealed enclosure -
here the sealed enclosure acts as a rear chamber and the trunk as the front chamber. and the ports open up into the listening area.. .. so basically it becomes an untuned 4th order Bandpass enclosure ( if the calculations for chamber and port tuning are not done )
2 - Ported enclosure - here the ported enclosure acts as a rear chamber, which is ported ( thru a tuned port ) into the trunk which can be considered as the front chamber, the trunk is then ported into the listening area, which makes this system a 6th order Bandpass.
A 6th order bandpass is known for really bad transient responses and can also unload a sub if not designed properly.
So as far as i understand , porting the trunk wud work much better in case of a sealed enclosure rather than a ported one..
Also , both the 4th and the 6th order Bandpass systems are known for netting higher SPL at the tuning frequency , so no wonder you get an acoustical raise of a couple of DB's.
and in all the ways you definitely need to consider the front chamber ( trunk volume ) calculations and the port tuning, if u dont do that, then u have to be plain lucky to get expected good results..
Thats what i understand of it..correct me if i am wrong anywhere..
Victor...
lessismorespl on 04/4/2005 10:07:09
You are exactly correct. I did not just say "hey, I'm gonna cut a couple holes in my rear deck and port the trunk." We took into account the volume of the trunk, where the enclosure was going to be placed and how it was going to be aimed, the volume of the cabin and what direction to aim the ports, we also did several calculations on where to place the ports for the best possible gain vs response. That is why, if you look at my pics on carstereo.com, the ports are about 5" apart in the center of my rear deck. If it was just a cosmetic thing, I'm sure I would have found a place to put them that looked much better than where I placed them, but in all my calculations, that was the best place to get not only the best gain, but to also get the best response. Another thing that has to be considered is sound dampening, if the trunk is not sealed and dampened properly, then the port will do nothing more than let more road noise into the cabin of the vehicle, so before I even considered porting the rear deck, I used 40 sq ft of sound dampening to make sure my trunk was free of road noise, in some places we used 2 layers, and we did the rear deck top & bottom w/ 2 layers, all together just in the rear deck and trunk there is easily 50+ sq ft of sound dampening. Aiming the enclosure is very important also, you can have the ports perfectly placed and the calaculations just right, (in my case 5" apart, 6" long), but if you do not figure in how the enclosure is aimed, you will get horrible SQ, much like how subs sound when they are on display or when you open your trunk, you get that sloppy muddy sound, so I used velcro to secure my enclosure down so it does not move out of place. installer.com was very helpful when it came to aiming the enclosure. I also did some minor inexspensive work to secure the outside of the car better: replaced the cheap factory plastic clips on the bumper cover w/ bolts and teflon lock nuts, secured sound dampening strips in between the bumper cover and the metal where I could get to it, used that $3 expanding foam where I could not get to. As for sound dampening, I need to do the front doors still, and would like to get to the floor boards in the front. The rear floor boards and doors are already done. Basically, if a person does not take the time to calculate several variables in SQ vs SPL when porting the trunk, you will end up w/ a huge mess and the best subs in the world would not sound good. Another thing I almost forget to mention, you also have to calculate the rear stage speakers, I used baffles and sound dampening there so they did not interfere w/ the sound coming through the ports, if you leave them open as is the case w/ most rear stage speakers, they will cause major port noise, kind of a whistling sound. I would not suggest porting the trunk unless you have vast experience in building enclosures, and are either a professional or have vast experience in car audio and know every angle and variable to do it right. Basically, your trunk is a secondary enclosure, so in altering anything within the trunk area, you must take the same vaiables as you do when building an enclosure into consideration.
MrBrownstone on 04/4/2005 13:03:51
Tuned to 35 Hz? What are you trying to do? kill your speakers?!!?!? Or is it a 'requirement' to play 41Hz through your system?
Wanna hit mid 150s? try 55 to 70Hz. More cabin gain. Vented @ 45 to 55 HZ should result in the proper box gain and combine with the cabin of the truck.
Please explain the rules of SLAP to me, because I'm used to DB DRAG. I hit 148.6 with 2 Audiobahn AW1200 and a 200Wx2 Audiobahn Amp in 2000. Super Street.
P0werLifter on 04/4/2005 14:17:37
Good replies so far. Please Keep in mind that I am currently competing with an Extended cab truck and the gains are different than a CRX or a car in that sense. Also bear in mind that currently the truck is not setup for pure SPL, this is an SQL setup for the time being but I'm going to start designing an SPL setup i can put in for competitions.
For the new enclosure type, im thinking about going with a Horn/Transmission Line enclosure to really maximize the gains out of the woofer. I'm also probably going to be purchasing a Digital Designs (DD) 9915 or an RE 18" MT. The only reason I might not go with the MT is talking to my good buddy who has been competing for a while and is on a team told me that they are very sensitive to the setup, if you get anything off what its supposed to be the setup will sound like crap. (At the show, with 1 12" MT he hit a 154.6dB with one Treo Amp in a CRX).
The other wierd thing is, with my enclosure tuned to 35hz, it peaks at 41 any higher and i loose my gain, I know, ive tested it lol but I'm taking out the enclosure within the month to build a sealed enclosure to really sit down and test the resonant frequency of the cab. Inside the cab I have 200sq feet of soundeadedning material.
Good advice victor, ive done most of it already but I do believe its time to change the gaskets on the windows, especially the back side windows because i KNOW im loosing SPL out of them. I had to replace one b4 the show due to it popping out whenever the bass hit.
The 1st thing on my list other than the new enclosure is more / better amplifiers. I can get Crossfire amplifiers that are fully modded at cost through my friend along with competitors prices on RE, Crossfire and some others.
List In order of purchase/manufacture
1. New Enclosure
2. Term Lab Sensor for testing at the house
3. New Amplifiers
4. New Woofer
5. New Automobile, most likely a CRX or similar hatchback
for SLAP rules go to SlapShow.com I believe is the layout. Classes are grouped by woofer Square inches.
Victor on 04/4/2005 15:29:18
hey PL i got a nice Horn loaded design to share with you.. will have to make a few changes tho cause this design was basically meant for 2 x 8"'s and 2 x 10"'s but can work out for 2 x 12"'s.
You may not need to have a 15" or a 18" sub to loose on SQ.. Instead 2 brahma or RE XXX 12" wud do wonders.. i can bet that any 2 of those in this enclosure will give you 160+ db even on its worst day ...
I had made one with 2 blau 10" velocity series 400wrms subs with an alpine MRD-1000 and they scored a whooping 143.07 db, which is unnatural for such subs to reach.
here is the over view and the construction for 8"s and 10"s if you are interested then we can together formulate for the 12" subs...THINK
OVERVIEW
http://www.decware.com/whorn.htm
CONSTRUCTION
http://www.decware.com/whornok.htm
FORUM specially dedicated to this enclosure ( surprised..eh..!!!)
http://www.decware.com/forums/Wicked/
Here's a post for modifications to be done for 12" subs..
http://decware.com/forums/Wicked/posts/882.html
Hope that helps..SMILE
Victor...
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