Made new vented box today, PICS...
10-09-2006, 08:57 PM
#41
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Am I correct in assuming that the purpose of doing this is to make both subs act as one single one(albeit:twice size/power)? so, if this is the case, wouldn't you have to make sure that they both were receiving the EXACT same signal(and I do mean totaly EXACT), and any difference would surely cause more problems than some tiny difference in box volume between the 2 sides when seperated?
also, if I did this, and somehow something happened to one of my subs and it quit working, now my other one is pounding away in a box twice the size it is supposed to be in(actually, since my box is so large and ported, it would be close to not being in a box at all-freeair no good), and will inevitably end up like the 1st...
please correct me if I am incorrect in anyhting I have previously mentioned.
-Matt
also, if I did this, and somehow something happened to one of my subs and it quit working, now my other one is pounding away in a box twice the size it is supposed to be in(actually, since my box is so large and ported, it would be close to not being in a box at all-freeair no good), and will inevitably end up like the 1st...
please correct me if I am incorrect in anyhting I have previously mentioned.
-Matt
10-10-2006, 08:25 AM
#42
Member
Join Date: Apr 2006
Posts: 95
If you were to blow one sub, sure, you'd still be able to run your system without an issues. A box like yours is great for that. Here's my experience in the past with enclosures of slightly different volumes.
I used to run Rockford Fosgate equipment, back in the day when I was first starting out. I was running four RF Punch 12" subs in a sealed enclosure, all common chamber, with 1.25 cubic feet per driver, and powering all four drivers off of a single RF Power 250.1 at 1 ohm, which was around 1200 watts or so. In my extended cab S10, i was able to achieve 151.1db. My charging system consisted of two batteries, and a 140 amp alternator. I then wanted more, and went out and bought another 250.1, and four more RF Punch 12's. I built another box, which at the time i was sure it was 1.25 cu. ft per driver, sealed again. I bridged the amps together, and ran all the subs together at a 2 ohm load. I bumped up my charging system, ran 4 batteries, and a 200 amp alternator. My SPL dropped down to 149.8 db. I couldn't believe it. Needless to say I wasn't too happy, and I then went through the entire system to figure it out. I tried running each box individually off of each amp individually to eliminate one or the other, until someone finally informed me about phasing issues. I remeasured the new box, and discovered it was built to 1.18 cu. ft. per driver. So, to fix this, I took out all eight drivers, left both boxes in the truck (one on top of the other, 4 wide), glued and screwed both boxes together, then cut out the joining wood to open both boxes up together, giving me a volume of just over 1.25 cu. ft per driver with the cut area removed. I then threw the subs back in, strapped the amps back together, and i was finally impressed with the system. My metered output increased from the 149.8 to 156.3 db, and it sounded better for music....not alot mind you, but slightly, unless that was all in my head.
Sorry for the novel, but in my opinion, you would probably like to get the most out of your equipment, and if there is a phasing issue that is holding you back, then why not fix it? The smallest differences in airspace and port volume can make quite the difference, and you wouldn't need to cut out a large area either....just enough to make it a common space. I'd even do it right in the trunk since it's so tight. Just my $.02.
I used to run Rockford Fosgate equipment, back in the day when I was first starting out. I was running four RF Punch 12" subs in a sealed enclosure, all common chamber, with 1.25 cubic feet per driver, and powering all four drivers off of a single RF Power 250.1 at 1 ohm, which was around 1200 watts or so. In my extended cab S10, i was able to achieve 151.1db. My charging system consisted of two batteries, and a 140 amp alternator. I then wanted more, and went out and bought another 250.1, and four more RF Punch 12's. I built another box, which at the time i was sure it was 1.25 cu. ft per driver, sealed again. I bridged the amps together, and ran all the subs together at a 2 ohm load. I bumped up my charging system, ran 4 batteries, and a 200 amp alternator. My SPL dropped down to 149.8 db. I couldn't believe it. Needless to say I wasn't too happy, and I then went through the entire system to figure it out. I tried running each box individually off of each amp individually to eliminate one or the other, until someone finally informed me about phasing issues. I remeasured the new box, and discovered it was built to 1.18 cu. ft. per driver. So, to fix this, I took out all eight drivers, left both boxes in the truck (one on top of the other, 4 wide), glued and screwed both boxes together, then cut out the joining wood to open both boxes up together, giving me a volume of just over 1.25 cu. ft per driver with the cut area removed. I then threw the subs back in, strapped the amps back together, and i was finally impressed with the system. My metered output increased from the 149.8 to 156.3 db, and it sounded better for music....not alot mind you, but slightly, unless that was all in my head.
Sorry for the novel, but in my opinion, you would probably like to get the most out of your equipment, and if there is a phasing issue that is holding you back, then why not fix it? The smallest differences in airspace and port volume can make quite the difference, and you wouldn't need to cut out a large area either....just enough to make it a common space. I'd even do it right in the trunk since it's so tight. Just my $.02.
10-10-2006, 12:38 PM
#43
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Originally Posted by ryanvalin
If you were to blow one sub, sure, you'd still be able to run your system without an issues. A box like yours is great for that. Here's my experience in the past with enclosures of slightly different volumes.
I used to run Rockford Fosgate equipment, back in the day when I was first starting out. I was running four RF Punch 12" subs in a sealed enclosure, all common chamber, with 1.25 cubic feet per driver, and powering all four drivers off of a single RF Power 250.1 at 1 ohm, which was around 1200 watts or so. In my extended cab S10, i was able to achieve 151.1db. My charging system consisted of two batteries, and a 140 amp alternator. I then wanted more, and went out and bought another 250.1, and four more RF Punch 12's. I built another box, which at the time i was sure it was 1.25 cu. ft per driver, sealed again. I bridged the amps together, and ran all the subs together at a 2 ohm load. I bumped up my charging system, ran 4 batteries, and a 200 amp alternator. My SPL dropped down to 149.8 db. I couldn't believe it. Needless to say I wasn't too happy, and I then went through the entire system to figure it out. I tried running each box individually off of each amp individually to eliminate one or the other, until someone finally informed me about phasing issues. I remeasured the new box, and discovered it was built to 1.18 cu. ft. per driver. So, to fix this, I took out all eight drivers, left both boxes in the truck (one on top of the other, 4 wide), glued and screwed both boxes together, then cut out the joining wood to open both boxes up together, giving me a volume of just over 1.25 cu. ft per driver with the cut area removed. I then threw the subs back in, strapped the amps back together, and i was finally impressed with the system. My metered output increased from the 149.8 to 156.3 db, and it sounded better for music....not alot mind you, but slightly, unless that was all in my head.
Sorry for the novel, but in my opinion, you would probably like to get the most out of your equipment, and if there is a phasing issue that is holding you back, then why not fix it? The smallest differences in airspace and port volume can make quite the difference, and you wouldn't need to cut out a large area either....just enough to make it a common space. I'd even do it right in the trunk since it's so tight. Just my $.02.
I used to run Rockford Fosgate equipment, back in the day when I was first starting out. I was running four RF Punch 12" subs in a sealed enclosure, all common chamber, with 1.25 cubic feet per driver, and powering all four drivers off of a single RF Power 250.1 at 1 ohm, which was around 1200 watts or so. In my extended cab S10, i was able to achieve 151.1db. My charging system consisted of two batteries, and a 140 amp alternator. I then wanted more, and went out and bought another 250.1, and four more RF Punch 12's. I built another box, which at the time i was sure it was 1.25 cu. ft per driver, sealed again. I bridged the amps together, and ran all the subs together at a 2 ohm load. I bumped up my charging system, ran 4 batteries, and a 200 amp alternator. My SPL dropped down to 149.8 db. I couldn't believe it. Needless to say I wasn't too happy, and I then went through the entire system to figure it out. I tried running each box individually off of each amp individually to eliminate one or the other, until someone finally informed me about phasing issues. I remeasured the new box, and discovered it was built to 1.18 cu. ft. per driver. So, to fix this, I took out all eight drivers, left both boxes in the truck (one on top of the other, 4 wide), glued and screwed both boxes together, then cut out the joining wood to open both boxes up together, giving me a volume of just over 1.25 cu. ft per driver with the cut area removed. I then threw the subs back in, strapped the amps back together, and i was finally impressed with the system. My metered output increased from the 149.8 to 156.3 db, and it sounded better for music....not alot mind you, but slightly, unless that was all in my head.
Sorry for the novel, but in my opinion, you would probably like to get the most out of your equipment, and if there is a phasing issue that is holding you back, then why not fix it? The smallest differences in airspace and port volume can make quite the difference, and you wouldn't need to cut out a large area either....just enough to make it a common space. I'd even do it right in the trunk since it's so tight. Just my $.02.
anyone else have any thoughts/opinions/arguments on the subject???
10-10-2006, 02:58 PM
#44
the thing is, you're ported. you will still retain the tuning frequency of the box even with the central brace/divider removed. port area is independant of the rest of the box. it's easier imo for a sub to hit xmech in a sealed box than ported one. ever seen a sub play at the tuning freq of the ported box? the sub isn't moving all that much, but it's stupid loud (it's a different story though if you play too low below tuning...which in that case the sub will unload very easily).
10-10-2006, 06:25 PM
#46
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Originally Posted by AscendantMax
the thing is, you're ported. you will still retain the tuning frequency of the box even with the central brace/divider removed. port area is independant of the rest of the box. it's easier imo for a sub to hit xmech in a sealed box than ported one. ever seen a sub play at the tuning freq of the ported box? the sub isn't moving all that much, but it's stupid loud (it's a different story though if you play too low below tuning...which in that case the sub will unload very easily).
Originally Posted by Smokin Max
That's nice work! How long did it take you to build? I thought about making one for my car awhile ago, but then got to lazy to do it, LOL!
10-10-2006, 09:26 PM
#47
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well, I've been playing with WinSD some more and thinking about the thoughts on common chamber and all that, and I have come to the conclusion that making a box that is already divided into a common chamber is not a good idea...
so, my problem: if you start with a ported box with a given volume, say 3.22cu.ft. for instance, with a port length of 23.75", tuned @ 36hz. If you leave everything else the same and add to the volume of that box(say, by removing some of the divider inside)making it now 3.45cu.ft, then you are effectivley going to lower the tuning frequency of the box and your SPL output will be lower. now, if you want to try and get back where you were before you messed with anything, you can try to shorten the port, but then you will have gained some spl, but lost some low end in the process because you have now reduced the size of the box and gained port area.
I could be wrong on this, as I have played around with ALOT of numbers, but it is my general thinking that changing my current setup the way it is would not be a good idea, if I wanted a common chamber, then I would have to start from scratch. please correct me if im wrong on any of this as I am by no means an expert but I do need to understand all this...
so, my problem: if you start with a ported box with a given volume, say 3.22cu.ft. for instance, with a port length of 23.75", tuned @ 36hz. If you leave everything else the same and add to the volume of that box(say, by removing some of the divider inside)making it now 3.45cu.ft, then you are effectivley going to lower the tuning frequency of the box and your SPL output will be lower. now, if you want to try and get back where you were before you messed with anything, you can try to shorten the port, but then you will have gained some spl, but lost some low end in the process because you have now reduced the size of the box and gained port area.
I could be wrong on this, as I have played around with ALOT of numbers, but it is my general thinking that changing my current setup the way it is would not be a good idea, if I wanted a common chamber, then I would have to start from scratch. please correct me if im wrong on any of this as I am by no means an expert but I do need to understand all this...
10-11-2006, 01:13 PM
#48
Member
Join Date: Apr 2006
Posts: 95
Keeping the same port volume, and increasing the airspace very minimally will not change the tuning of the box. You to not need to remove the entire divider either. Cut a hole in it 8x8" or so. If you used 3/4" mdf, and it looks as if you did on your box, that will only increase your airspace by just under .03 cubic feet.
10-15-2006, 03:45 PM
#49
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Join Date: Oct 2006
Location: Hyattsville, MD
Posts: 179
Originally Posted by MadMaxSE-L
took me about 3-4 hrs to do the wood work(including measuring the car and cutting wood), 30min to put most of it together(all but the face), ran to the store to get undercoating while silicone was drying, undercoated it, then put the face on and let dry for the rest of the day, so all in all about 6-7hrs of actual work from time of initial measurment to when I was trying to finagle it into my trunk. definatley make one d00d, you'll be glad you did when you first turn it on and it pops the speaker grills off the back deck like mine did...
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