The SPL tips thread.
04-18-2005, 08:13 AM
#1
Well... people are always complaining that we never share. So here is a great thread I've found on a UK board. I'll just pull out the "tips" part. If you want to read the whole thing, it can be found HERE!
a few people of late have been testing with sealed boxes in the open, then with sealed boxes in the cars to find the peak frequency! this is pointless unless you try every conceivable option for aiming the subs, distance from panels will change the results too!
far better to do the same as with walls! start with the biggest box ya can, then test every box size/port area/length combination ya can, this will then help ya to find the peak in ya car, but ya not done yet!!
spl secrets (i could tell ya then i'd have to kill ya!):-
i, try removing all corners in ya box! 3" wide strips of wood, with 45 degree angles cut on opposing sides, so they fit into the corners of your box, this in effect takes out dead areas in ya box, so helping the pressure to leave the box via the port, not sit in corners twidling its thumbs!!
ii, try different sub port positioning, conventional wisdom says the sub and port must be on the same face, spl takes the sq fairys rules and throws them away!
iii, aeroports are good, these are not any better/worse than slot ports, but the european street cars use em, and they are damn loud, so they can't be bad!!
iv, if ya got an idea try it!, people bein different is why 5 years ago 150db made ya a god, but now it is run of the mill! my car doin 153.4 db was unthinkable, but now it is nothing!! new ideas are what make this sport/hobby what it is!!
v, for ports in walls, make the port no longer than 80-100mm, this results in better airflow from ya port, also radius the edge of it, this results in better airflow too!!
vi, DO NOT bend ports for spl!!!! this slows the air thus reducing spl!!
vii, seal the inside of ya box with fibre glass resin, this also increases the natural resonance of ya box, helps to pick ya note up a little ie plays 46hz, instead of 45.
viii, make box stiff, with no internal bracing, this again slow the airflow down!! if ya must brace it, use external!!
ix, smaller boxes peak at higher notes than big ones, and vice versa!
x, don't write all this out, then click on pm's when ya notice ya got some, this loses the stuff ya just spent ten minutes writing!!
xi, above all get the most power you can!! power is spl!!!!!!
xii, get loud!!!
xiii, get an spl meter. or the use of one!, what sounds loud ain't normally loudest!!! this should be bought before subs and amps, if ya serious about spl!!!
xiv, enjoy it! i know i do!!
xv, any questions just ask!!
and theres more:-
i, when trying to work out port area, a rough guestiamte at largest area is the sd of ya subs, so a single fifteen would be roughly 175 sq ins of port, a single twelve approx 110 sq ins. these are of course a good idea for starting if ya can get the port to tune low enough, don't worry if ya can't get this size port in!!!
ii, when building boxes for multiple subs, try and keep the box symetrical, so if ya using two tens put em in identical positions at opposite ends of the box, with port in the middle, so the box looks symetrical!
iii, in walls keep the subs as far over to the mic side of the car as possible, and in as straight a line upward as ya can, again symetrical up and down is good!
iv, keep the subs at least four ins away from the edge of any ports, this helps load the subs better! especially when using the port lengths from v, above!
v, air moves from high pressure areas to low pressure areas!
vi, boxes don't have to be square (see rule v,)
vii, opposite corners of a good loud car are always loud, ie mic position and rear opposite corner
viii, air moves over smooth surfaces better than rough unfinished surfaces!
ix, power caps..............don't help spl!!!
x, buy the biggest most powerful batterys ya can, but don't go too big, street has a size limit ya know (800 sq ins) and don't forget alts either, its all well and good having the biggest batterys in the world, but if ya can't recharge em they are useless!
xi, in street leave ya engine running for as long as poss before a burp, and turn it off at the last minute, this gives as much surface charge as ya can get on ya battery which can only help ya score! do not start ya car then enter the lanes straight away as starting ya car flattens ya battery a fair bit so defeats any charge that will be put back in! start it and leave it running at highish idle for a good few mins before!! (read as long as is safe to do so!
building walls i think this time!!
i, work out where everything will go before even buying wood!
ii, wood does bend, mdf i particular, slice thru it, leaving 4mm of wood on the outside of the bend point, this will allow the wood to bend but not split!
iii, best item to do the above cut is a circular saw with a depth setting on it set to thickness of wood minus 4mm(obviously)
iv, expanding foam is good for reinforcing bond to outside of car, but no substitute for extra wood where ya can! ie where the window is, even if ya can't get it to fit exactly, cut a piece of wood that is 2" smaller all the way round, trial fit ya wood, work out where the recess is on the side piece and screw recess piece to the outside of wood so it drops into the recess when panel is fixed permanently!
v, from my experience do the same as above with roof section, this will help stiffness no end!! even if it means a strip that is considerably narrower than the roof panel itself, every little helps!!
vi, make box as big as ya can, this will be for testing purposes! easy to make it smaller, but harder to make it bigger!! (especially when reinforced with enoguh steel to make a small tank!! )
vii, where ya have to fix panels to the matal at the sides of the car, cut strips that will fit behind the metalwork, then secure with a screw at either end to secure in place, then when ya screw upto the side panel you have summat solid to screw into, not just a piece of tinfoil!
viii, silicone is ya best friend also, floorpanels can be fixed in a rather pemanent manner with it to the floor, but will also be able to be able to be pryed away with a little persuasion!
ix, corners are just as important in large boxes aswell, try to remove corners, this will remove dead spots where pressure will sit!
x, when joining ya roof panels to side panels, use double thick sides, but cut em two thicknesses of your material to short/wide, this will enable ya to cut a strip of ya chosen matereial twice as deep as it is thick and screw it into place on top of ya side and on the bottom, now ya side is the right height and ya have a handy lip to screw to the top/bottom/back/front of ya box, then just add ya second side piece to the recess ya made with ya "screw lips" this will strengthen ya box no end and allow ya to screw directly up into whatever panel ya want to fix it too!!
xi, when tunig ya enclosure, try to keep ya port roughly symetrical!
xi, subs as far over to pass side as poss, port edge as close to the bpost as ya can!! this will help the pressure from the drivers/port to couple with the sides of the vehicle better!!
xii, if ya got really big panels and ya have to brace em, use threaded bar by all means, but use a piece of steel tube thats a clearance fit for it, and some big washers, and actuaslly tighten the oposing ides of the box to the bar, this will smoth airflow in the box no end = spl gains!
If you've got other tips to add, please do.
If you disagree with this please do it like a "big boy" and state your case intelligently. (add what may help instead is also a good idea) [img]graemlins/thumb.gif[/img]
[ April 18, 2005, 09:15 AM: Message edited by: JordyO ]
a few people of late have been testing with sealed boxes in the open, then with sealed boxes in the cars to find the peak frequency! this is pointless unless you try every conceivable option for aiming the subs, distance from panels will change the results too!
far better to do the same as with walls! start with the biggest box ya can, then test every box size/port area/length combination ya can, this will then help ya to find the peak in ya car, but ya not done yet!!
spl secrets (i could tell ya then i'd have to kill ya!):-
i, try removing all corners in ya box! 3" wide strips of wood, with 45 degree angles cut on opposing sides, so they fit into the corners of your box, this in effect takes out dead areas in ya box, so helping the pressure to leave the box via the port, not sit in corners twidling its thumbs!!
ii, try different sub port positioning, conventional wisdom says the sub and port must be on the same face, spl takes the sq fairys rules and throws them away!
iii, aeroports are good, these are not any better/worse than slot ports, but the european street cars use em, and they are damn loud, so they can't be bad!!
iv, if ya got an idea try it!, people bein different is why 5 years ago 150db made ya a god, but now it is run of the mill! my car doin 153.4 db was unthinkable, but now it is nothing!! new ideas are what make this sport/hobby what it is!!
v, for ports in walls, make the port no longer than 80-100mm, this results in better airflow from ya port, also radius the edge of it, this results in better airflow too!!
vi, DO NOT bend ports for spl!!!! this slows the air thus reducing spl!!
vii, seal the inside of ya box with fibre glass resin, this also increases the natural resonance of ya box, helps to pick ya note up a little ie plays 46hz, instead of 45.
viii, make box stiff, with no internal bracing, this again slow the airflow down!! if ya must brace it, use external!!
ix, smaller boxes peak at higher notes than big ones, and vice versa!
x, don't write all this out, then click on pm's when ya notice ya got some, this loses the stuff ya just spent ten minutes writing!!
xi, above all get the most power you can!! power is spl!!!!!!
xii, get loud!!!
xiii, get an spl meter. or the use of one!, what sounds loud ain't normally loudest!!! this should be bought before subs and amps, if ya serious about spl!!!
xiv, enjoy it! i know i do!!
xv, any questions just ask!!
and theres more:-
i, when trying to work out port area, a rough guestiamte at largest area is the sd of ya subs, so a single fifteen would be roughly 175 sq ins of port, a single twelve approx 110 sq ins. these are of course a good idea for starting if ya can get the port to tune low enough, don't worry if ya can't get this size port in!!!
ii, when building boxes for multiple subs, try and keep the box symetrical, so if ya using two tens put em in identical positions at opposite ends of the box, with port in the middle, so the box looks symetrical!
iii, in walls keep the subs as far over to the mic side of the car as possible, and in as straight a line upward as ya can, again symetrical up and down is good!
iv, keep the subs at least four ins away from the edge of any ports, this helps load the subs better! especially when using the port lengths from v, above!
v, air moves from high pressure areas to low pressure areas!
vi, boxes don't have to be square (see rule v,)
vii, opposite corners of a good loud car are always loud, ie mic position and rear opposite corner
viii, air moves over smooth surfaces better than rough unfinished surfaces!
ix, power caps..............don't help spl!!!
x, buy the biggest most powerful batterys ya can, but don't go too big, street has a size limit ya know (800 sq ins) and don't forget alts either, its all well and good having the biggest batterys in the world, but if ya can't recharge em they are useless!
xi, in street leave ya engine running for as long as poss before a burp, and turn it off at the last minute, this gives as much surface charge as ya can get on ya battery which can only help ya score! do not start ya car then enter the lanes straight away as starting ya car flattens ya battery a fair bit so defeats any charge that will be put back in! start it and leave it running at highish idle for a good few mins before!! (read as long as is safe to do so!
building walls i think this time!!
i, work out where everything will go before even buying wood!
ii, wood does bend, mdf i particular, slice thru it, leaving 4mm of wood on the outside of the bend point, this will allow the wood to bend but not split!
iii, best item to do the above cut is a circular saw with a depth setting on it set to thickness of wood minus 4mm(obviously)
iv, expanding foam is good for reinforcing bond to outside of car, but no substitute for extra wood where ya can! ie where the window is, even if ya can't get it to fit exactly, cut a piece of wood that is 2" smaller all the way round, trial fit ya wood, work out where the recess is on the side piece and screw recess piece to the outside of wood so it drops into the recess when panel is fixed permanently!
v, from my experience do the same as above with roof section, this will help stiffness no end!! even if it means a strip that is considerably narrower than the roof panel itself, every little helps!!
vi, make box as big as ya can, this will be for testing purposes! easy to make it smaller, but harder to make it bigger!! (especially when reinforced with enoguh steel to make a small tank!! )
vii, where ya have to fix panels to the matal at the sides of the car, cut strips that will fit behind the metalwork, then secure with a screw at either end to secure in place, then when ya screw upto the side panel you have summat solid to screw into, not just a piece of tinfoil!
viii, silicone is ya best friend also, floorpanels can be fixed in a rather pemanent manner with it to the floor, but will also be able to be able to be pryed away with a little persuasion!
ix, corners are just as important in large boxes aswell, try to remove corners, this will remove dead spots where pressure will sit!
x, when joining ya roof panels to side panels, use double thick sides, but cut em two thicknesses of your material to short/wide, this will enable ya to cut a strip of ya chosen matereial twice as deep as it is thick and screw it into place on top of ya side and on the bottom, now ya side is the right height and ya have a handy lip to screw to the top/bottom/back/front of ya box, then just add ya second side piece to the recess ya made with ya "screw lips" this will strengthen ya box no end and allow ya to screw directly up into whatever panel ya want to fix it too!!
xi, when tunig ya enclosure, try to keep ya port roughly symetrical!
xi, subs as far over to pass side as poss, port edge as close to the bpost as ya can!! this will help the pressure from the drivers/port to couple with the sides of the vehicle better!!
xii, if ya got really big panels and ya have to brace em, use threaded bar by all means, but use a piece of steel tube thats a clearance fit for it, and some big washers, and actuaslly tighten the oposing ides of the box to the bar, this will smoth airflow in the box no end = spl gains!
If you disagree with this please do it like a "big boy" and state your case intelligently. (add what may help instead is also a good idea) [img]graemlins/thumb.gif[/img]
[ April 18, 2005, 09:15 AM: Message edited by: JordyO ]
04-18-2005, 08:39 AM
#3
50 Watt CAFz'r
Join Date: Dec 2004
Posts: 242
hey jordyo, i am very greatful for you puting that up here and as well to the person who put up the thread from a while back with all the tips in it. it helped me out and i enjoy reading about what other people are doing to get loud as well, and that way i can integrate some ideas into my setup. i think its a great thread ...IMO
04-18-2005, 09:13 AM
#4
1000 Watt CAFz'r
Join Date: Mar 2004
Posts: 1,093
Originally posted by Chevy Man:
hey jordyo, i am very greatful for you puting that up here and as well to the person who put up the thread from a while back with all the tips in it. it helped me out and i enjoy reading about what other people are doing to get loud as well, and that way i can integrate some ideas into my setup. i think its a great thread ...IMO
hey jordyo, i am very greatful for you puting that up here and as well to the person who put up the thread from a while back with all the tips in it. it helped me out and i enjoy reading about what other people are doing to get loud as well, and that way i can integrate some ideas into my setup. i think its a great thread ...IMO
there will be more to come. i've jst been very busy and stuff wiyth work, and the moving to post much!
but yeah as soon as i get testing, more hints, tips, and idea's will be shared throughout the board! Great post Jordy!
[img]graemlins/bow.gif[/img]
Livin loud
04-18-2005, 09:48 AM
#5
Originally posted by Livin - Loud:
</font><blockquote>quote:</font><hr />Originally posted by Chevy Man:
hey jordyo, i am very greatful for you puting that up here and as well to the person who put up the thread from a while back with all the tips in it. it helped me out and i enjoy reading about what other people are doing to get loud as well, and that way i can integrate some ideas into my setup. i think its a great thread ...IMO
</font><blockquote>quote:</font><hr />Originally posted by Chevy Man:
hey jordyo, i am very greatful for you puting that up here and as well to the person who put up the thread from a while back with all the tips in it. it helped me out and i enjoy reading about what other people are doing to get loud as well, and that way i can integrate some ideas into my setup. i think its a great thread ...IMO
there will be more to come. i've jst been very busy and stuff wiyth work, and the moving to post much!
but yeah as soon as i get testing, more hints, tips, and idea's will be shared throughout the board! Great post Jordy!
[img]graemlins/bow.gif[/img]
Livin loud </font>[/QUOTE]Curtis... answer PM's.. I need an answer ASAP [img]tongue.gif[/img]
04-18-2005, 03:34 PM
#10
500 Watt CAFz'r
Join Date: Apr 2000
Posts: 890
Since there is some negative people posting here is some positive feed back.
Imo try to stay away from the silicone`s (unless it`s around the windows ect.) because it will flex under pressure, we used to do it, but bondo, short strand fiberglass, will be stronger. Some surfaces you want to be smooth but certian areas you want it to be rough, test to find out. Use external ports, as we have found out the past 2 years now that they are louder, if you can. Also some cornors you want to be square not always round, test to find out again.
One of the biggest tips on here is to get a meter and test! No test is a dumb test.
Imo try to stay away from the silicone`s (unless it`s around the windows ect.) because it will flex under pressure, we used to do it, but bondo, short strand fiberglass, will be stronger. Some surfaces you want to be smooth but certian areas you want it to be rough, test to find out. Use external ports, as we have found out the past 2 years now that they are louder, if you can. Also some cornors you want to be square not always round, test to find out again.
One of the biggest tips on here is to get a meter and test! No test is a dumb test.
