hi all, i have two questions...
1) i have this qlogic box...
https://www.crutchfield.com/S-u9wH1OjCsYa/cgi-bin/ProdView.asp?g=178750&id=detailed_info&i=044QB1103#Tab
...i have had it over a year and it sounds great to me at low to mid levels but a bit undefined at higher volumes. when i first installed it i used a chart that came with the enclosure to cut the ports. i had no idea what i was doing at the time but i think both ports are about 2/3rds of the size they used to be after cutting them.
anyways, i got a new amp for the sub and have been tuning the system again and thought to check online this time to see if what i had done to the ports was right, wrong, or otherwise. while trying to find specs on the box i began to notice that all the diagrams have the FACE of the sub pointing towards the PORTED chamber with the MAGNET in the SEALED chamber.
that brings me to my first question... if you look at the link above at my box, can someone please tell me whether the FACE or the MAGNET should be visible in the plexiglass section of the box? i installed it with the face showing but i'm not so sure if that's the correct way at this point - or could it be that this is just a badly designed box?
my second question is if i do have the sub installed correctly AND the specs on this box are as follows...
ported chamber = 0.53 cu ft
sealed chamber = 0.48 cu ft
2x 3" dia. ports
...what is my ideal port legnth? i have tried using the calculator however it seems to be meant for single port enclosures and this box has two ports. i also tried finding an equation w/ an option for two ports instead of one but was unsucessful.
thanx in advance for any help on this!
rtb
It doesn't matter which way the woofer is installed, as it produces sound waves in both directions. You should switch the polarity both ways and use the way that results in the most bass output or best sound. The description in that link suggests that the cone faces the window...the way you did it: "Note: Due to the position of the port tubes in the enclosure, the mounting depth can be limited for a top-mounted woofer with a large magnet."
But building a proper bandpass box is complex. The magnet assembly takes up air space and fitting it one way might work for the net air volume while fitting it the other way would not work. There has to be a precise volume of net air space in each chamber after the sub is installed. All bandpass enclosures should be custom-built by a pro.
I would suggest that you've got your money's worth out of this bandpass box and it's time to use the experience you've gained so far and build a new box. Pre-built, all purpose, 5/8" bandpass boxes are never a good idea for any situation. What subwoofer are you using? You should build the proper sealed or vented enclosure designed for that particular sub. There are plenty of free help calculators and programs if you want to delve into it.
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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
stevdart wrote:
It doesn't matter which way the woofer is installed, as it produces sound waves in both directions. You should switch the polarity both ways and use the way that results in the most bass output or best sound. The description in that link suggests that the cone faces the window...the way you did it: "Note: Due to the position of the port tubes in the enclosure, the mounting depth can be limited for a top-mounted woofer with a large magnet."
But building a proper bandpass box is complex. The magnet assembly takes up air space and fitting it one way might work for the net air volume while fitting it the other way would not work. There has to be a precise volume of net air space in each chamber after the sub is installed. All bandpass enclosures should be custom-built by a pro.
I would suggest that you've got your money's worth out of this bandpass box and it's time to use the experience you've gained so far and build a new box. Pre-built, all purpose, 5/8" bandpass boxes are never a good idea for any situation. What subwoofer are you using? You should build the proper sealed or vented enclosure designed for that particular sub. There are plenty of free help calculators and programs if you want to delve into it.
thanx so much for your input m8 - i am a novice at diy but have had $5K systems in the past but have toned it down quite a bit since i got married and been blessed with our small tribe of 4 kids :)
i still have to have more than stock though so i've been value hunting and trying less expensive equipment as well as starting to save by doing a lot of my own upgrades since the majority of the wires are already ran to the back of my suv.
enough about me - to answer your question, the sub i'm running i got on a super deal (an honored price mistake) from circuit city of all places - very surprised they honored it. it's an [b]infinity reference 1030[/b]. ended up paying about $15 after rebates.
i looked for the Vas and Fs for the sub but couldn't find anything on it... it may have helped if i knew what either of those meant - lol! okay i found them here...
https://www.diysubwoofers.org/define.htm
...however, that doesn't help me much :(
anyways, is it not possible for me to get an appox. "ideal" legnth for the ports given the info i have at this point or am still missing some values?
i'm adding a reply as i don't see where i am able to edit the post above... is that option off limits atm?
i wanted to add this question...
is there a way for me to tell whether or not this box / ports are tuned correctly by just listening to it? i mean the darn thing simply bangs but i'd still like to know if there is room for improvement.
OR
is there a way for me to use the Port Length Calculator to calculate the ideal length of my two ports in this box for this sub?
You've said twice now that it sounds good. Bandpass will exhibit limitations in sound quality with any driver, though, so tweaking this particular enclosure may be a fruitless adventure. If you want to learn more about bandpass, use the info in the DIYsub link you showed above: https://www.diysubwoofers.org/bnd/4thorder.htm
Find the complete list of parameters for that subwoofer. WinISDPro is a free program that can help you find the port size. Unibox is another. And these calculators are helpful in any case. You will likely find that the ideal enclosure for that sub is not bandpass at all.
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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
stevdart wrote:
You've said twice now that it sounds good. Bandpass will exhibit limitations in sound quality with any driver, though, so tweaking this particular enclosure may be a fruitless adventure. If you want to learn more about bandpass, use the info in the DIYsub link you showed above: https://www.diysubwoofers.org/bnd/4thorder.htm
Find the complete list of parameters for that subwoofer. WinISDPro is a free program that can help you find the port size. Unibox is another. And these calculators are helpful in any case. You will likely find that the ideal enclosure for that sub is not bandpass at all.
Thanx a bunch m8!
I'll check out the programs and see what I come up with.
rtb