Ports & boxes & XO's... Oh my!!!
05-11-2006, 05:30 PM
#1
500 Watt CAFz'r
Thread Starter
Join Date: Apr 2004
Posts: 756
Ports & boxes & XO's... Oh my!!!
So... I just aquired an old table saw & I've got plans & ports (thanks to A-Team Audio!) for a new SQ box. But of course, I have tons of questions, and since I never get the time to come and just hang out and help out and learn stuff on the local build nights (something that's gonna change soon yay!), I'm hoping some of you guys can give me some tips here
A warning - I'm long winded on a keyboard...
First, these plans were drawn up a few months ago, and I just haven't had the time to get on it, till now. The box is for my 12in. sub, sub & aeroports all facing out the baffle, similar to my existing box, but with aeroports:
(my existing dual purpose box - 50hz for comp, and plug one of the ports for 33hz for daily)
The new plans are:
OSM: 32L x 18W x 12H
ISM: 30.5L x 16.5W x 10.5H = 3.06 cu/ft gross
Total Displacement = 0.75 cu/ft
· Sub = 0.39 cu/ft
· (2) 4” aeroports @ 24”L each = 0.24 cu/ft
· (2) Corners, 5” x 16.5” w/ 45° angles = 0.12 cu/ft
Net Volume = 2.31 cu/ft
Tuning Frequency = 32hz
Cut Out Diameters:
· Sub = 11.25” Dia. – 5.625 radius
· Ports = 6.25” Dia. – 3.125 radius
Cuts:
· Top & Bottom = (2) @ 32” x 18”
· Sides = (2) @ 31.25 x 10.5
· Ends = (2) @ 17.25 x 10.5
· Corners = (2) @ 5 x 16.5 w/ 45° angles
So, my first issue is my port tuning frequency. I got it in my head that I want 29, but people advise higher, like the 32 above. But I'm thinking that since I've never had anyone advise me on my XO settings, maybe I'm doin' it wrong and that's why I'm thinking of lowering my tuning...
The XO setting in question is, of course, the "IntelliQ Bass Optimization Circuit" on my Orion 1200D's. As instructed in the amp's manual's, I set the IntelliQ to the port tuning frequency of my existing box (33-34hz). To do this, (the IntelliQ has two rhetostats, one for freq, and one for boost), I get a 33hz tone going at a medium volume, crank the boost up to 60 or 70%, and lower the frequency setting until the sub starts "jumping out of the box". I then lower the boost to a more reasonable setting, which gives the sub a 2 to 3db boost at the tuning frequency, and "gives more output at lower frequencies without the danger of over-excursion". Since I run my two amps unbridged for daily use @ 2 ohms, I do this twice, once on each amp/coil. When I have them bridged down to 1, I can use the Master/Slave setting and I only have to set one of the amps.
My problem? The system lacks gut wrenching low end bass, until I lower the freq. setting "just a bit more". From what I understand, this is lowering my boost freq and cutoff slope for the lower frequencies. Lowering it a bit more seems to work fine, but then I figure the system isn't optimized anymore and I should be doing something different to get that extra 1/2 db out of it all... And I'm scared to really crank it up because of all the warnings about playing notes lower than your tuning frequency, especially boosted ones.
K, it's taken a long time to get here eh... My first question! Am I going about this the right way? I've been thinking that maybe I should be lowering that frequency setting to the lowest point of where the boost is obvious, rather than the highest like I've been doing.
But then wouldn't the boost be set at, say, 30, even though the port is 33, and then that could damage the sub?
During comps, I shut off all XO's and IntelliQ's.
Alright, onwards...
After I get this SQ box built, I'll start on a new competition box. I'll be transfering my sub and aeroports from the SQ box, to the comp box for comps, and then back again on Monday mornings. At least, in theory, for now. In reality I'll probably pony up the dough for an extra set of aeroports
I like the numbers that the popular small box, external aeroports setups that I've seen have been achieving. Suggestions on measurements, or should I just slap, say a 1.2 cu footer together and try it out?
And next, peak van frequencies. I've never tested for this, the box I have was given to me (thanx Rob!) with a port freq of 50 already, so that's what I use. I've heard that to test the van's peak, I need to slap my sub into a sealed box and run some sweeps, while on a meter. Can I just plug off both ports in my box and call it a sealed box good enough for the peak testing?
Thanks for any & all help guys!
A warning - I'm long winded on a keyboard...
First, these plans were drawn up a few months ago, and I just haven't had the time to get on it, till now. The box is for my 12in. sub, sub & aeroports all facing out the baffle, similar to my existing box, but with aeroports:
(my existing dual purpose box - 50hz for comp, and plug one of the ports for 33hz for daily)
The new plans are:
OSM: 32L x 18W x 12H
ISM: 30.5L x 16.5W x 10.5H = 3.06 cu/ft gross
Total Displacement = 0.75 cu/ft
· Sub = 0.39 cu/ft
· (2) 4” aeroports @ 24”L each = 0.24 cu/ft
· (2) Corners, 5” x 16.5” w/ 45° angles = 0.12 cu/ft
Net Volume = 2.31 cu/ft
Tuning Frequency = 32hz
Cut Out Diameters:
· Sub = 11.25” Dia. – 5.625 radius
· Ports = 6.25” Dia. – 3.125 radius
Cuts:
· Top & Bottom = (2) @ 32” x 18”
· Sides = (2) @ 31.25 x 10.5
· Ends = (2) @ 17.25 x 10.5
· Corners = (2) @ 5 x 16.5 w/ 45° angles
So, my first issue is my port tuning frequency. I got it in my head that I want 29, but people advise higher, like the 32 above. But I'm thinking that since I've never had anyone advise me on my XO settings, maybe I'm doin' it wrong and that's why I'm thinking of lowering my tuning...
The XO setting in question is, of course, the "IntelliQ Bass Optimization Circuit" on my Orion 1200D's. As instructed in the amp's manual's, I set the IntelliQ to the port tuning frequency of my existing box (33-34hz). To do this, (the IntelliQ has two rhetostats, one for freq, and one for boost), I get a 33hz tone going at a medium volume, crank the boost up to 60 or 70%, and lower the frequency setting until the sub starts "jumping out of the box". I then lower the boost to a more reasonable setting, which gives the sub a 2 to 3db boost at the tuning frequency, and "gives more output at lower frequencies without the danger of over-excursion". Since I run my two amps unbridged for daily use @ 2 ohms, I do this twice, once on each amp/coil. When I have them bridged down to 1, I can use the Master/Slave setting and I only have to set one of the amps.
My problem? The system lacks gut wrenching low end bass, until I lower the freq. setting "just a bit more". From what I understand, this is lowering my boost freq and cutoff slope for the lower frequencies. Lowering it a bit more seems to work fine, but then I figure the system isn't optimized anymore and I should be doing something different to get that extra 1/2 db out of it all... And I'm scared to really crank it up because of all the warnings about playing notes lower than your tuning frequency, especially boosted ones.
K, it's taken a long time to get here eh... My first question! Am I going about this the right way? I've been thinking that maybe I should be lowering that frequency setting to the lowest point of where the boost is obvious, rather than the highest like I've been doing.
But then wouldn't the boost be set at, say, 30, even though the port is 33, and then that could damage the sub?
During comps, I shut off all XO's and IntelliQ's.
Alright, onwards...
After I get this SQ box built, I'll start on a new competition box. I'll be transfering my sub and aeroports from the SQ box, to the comp box for comps, and then back again on Monday mornings. At least, in theory, for now. In reality I'll probably pony up the dough for an extra set of aeroports
I like the numbers that the popular small box, external aeroports setups that I've seen have been achieving. Suggestions on measurements, or should I just slap, say a 1.2 cu footer together and try it out?
And next, peak van frequencies. I've never tested for this, the box I have was given to me (thanx Rob!) with a port freq of 50 already, so that's what I use. I've heard that to test the van's peak, I need to slap my sub into a sealed box and run some sweeps, while on a meter. Can I just plug off both ports in my box and call it a sealed box good enough for the peak testing?
Thanks for any & all help guys!
05-12-2006, 03:16 PM
#3
Administrator
Join Date: Feb 2006
Posts: 16,855
Gut wrenching low end? For sure, you have a tonne of power and a great woofer but it IS a single 12 and while it spunds awesome, to really jiggle your bowels, especially in a van, you may need more cone... Just run out and buy 5 more 
05-12-2006, 06:18 PM
#4
500 Watt CAFz'r
Thread Starter
Join Date: Apr 2004
Posts: 756
Actually, as an experiment, I shut off the IntelliQ today...
THERE'S the sound I've been looking for all this time! I must be going about setting that damned thing wrong or something, 'cause today it sounds deadly, with low low notes I haven't heard before. I never did play any Bass Mekanik or anything with big low tones, so as long as I use caution if I do, things may go well...
So, I guess next is try to tune the IntelliQ lower... with a 30 or 29hz tone, and see what happens...
THERE'S the sound I've been looking for all this time! I must be going about setting that damned thing wrong or something, 'cause today it sounds deadly, with low low notes I haven't heard before. I never did play any Bass Mekanik or anything with big low tones, so as long as I use caution if I do, things may go well...
So, I guess next is try to tune the IntelliQ lower... with a 30 or 29hz tone, and see what happens...
05-25-2006, 08:05 AM
#7
50 Watt CAFz'r
Join Date: May 2005
Posts: 91
(GrizZz here, wife's PC)
K, box building is going well I was up at the lake this weekend where a buddy of mine has a full woodworking shop and had him cut up a sheet of MDF for me... Brought my pieces back here and have been assembling
Glue is now drying...
Where to get some fibreglass resin to coat the inside? How much will I need and what should I be lookin' at for cost?
Oh hey... so I've test fitted the ports and all, and run into a snag... The ports and sub are all on the baffle board, so the ports turn 90 degrees and then continue on for 15 or so inches before they end. Problem is, the bottom of the inside flared piece is touching the bottom of the box... Which will create one helluva rattle, I'm sure.
Only Idea I've come up with so far is to fabricate a thin metal bracket, and screw the bottom of that flared piece into a bracket that's screwed to the bottom of the box.... Sound good?
K, box building is going well I was up at the lake this weekend where a buddy of mine has a full woodworking shop and had him cut up a sheet of MDF for me... Brought my pieces back here and have been assembling
Glue is now drying...Where to get some fibreglass resin to coat the inside? How much will I need and what should I be lookin' at for cost?
Oh hey... so I've test fitted the ports and all, and run into a snag... The ports and sub are all on the baffle board, so the ports turn 90 degrees and then continue on for 15 or so inches before they end. Problem is, the bottom of the inside flared piece is touching the bottom of the box... Which will create one helluva rattle, I'm sure.
Only Idea I've come up with so far is to fabricate a thin metal bracket, and screw the bottom of that flared piece into a bracket that's screwed to the bottom of the box.... Sound good?
05-25-2006, 08:25 AM
#8
500 Watt CAFz'r
Join Date: Nov 2004
Posts: 779
Originally Posted by GrizZzled
Oh hey... so I've test fitted the ports and all, and run into a snag... The ports and sub are all on the baffle board, so the ports turn 90 degrees and then continue on for 15 or so inches before they end. Problem is, the bottom of the inside flared piece is touching the bottom of the box... Which will create one helluva rattle, I'm sure.
Only Idea I've come up with so far is to fabricate a thin metal bracket, and screw the bottom of that flared piece into a bracket that's screwed to the bottom of the box.... Sound good?
05-31-2006, 08:45 PM
#9
50 Watt CAFz'r
Join Date: May 2005
Posts: 91
(GrizZz here, wife's PC)
Just got my new daily SQ box back from Line-X Calgary South. They sprayed the box for me, as they did last time for my SQ/SPL combo box.
This time, however, I had them spray the inside of the box smooth, and "just thick enough, don't get carried away.". The outside, I said "Do what you want, as thick as you want."
This, is the result. The pictures kinda suck, but they work, trust me though, it is sweet. It is quite smooth inside, not glassy smooth but not even as dimply as a golf ball...
(sorry, I tried to get the images to reduce size in UBB code like ya can in HTML, but I can't figure out how!)
Dying to stick my sub in it, but I'll wait until I get back from Castlegar on Monday. If I have room in the van though, I'll drag it along to show off...
Just got my new daily SQ box back from Line-X Calgary South. They sprayed the box for me, as they did last time for my SQ/SPL combo box.
This time, however, I had them spray the inside of the box smooth, and "just thick enough, don't get carried away.". The outside, I said "Do what you want, as thick as you want."
This, is the result. The pictures kinda suck, but they work, trust me though, it is sweet. It is quite smooth inside, not glassy smooth but not even as dimply as a golf ball...
(sorry, I tried to get the images to reduce size in UBB code like ya can in HTML, but I can't figure out how!)
Dying to stick my sub in it, but I'll wait until I get back from Castlegar on Monday. If I have room in the van though, I'll drag it along to show off...
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