I have a BP box that was tuned for a diffrent set of subs, and one of the ports are missing . I am not too sure but if I tune the ports to my subs , it should make a diffrence ?? right? Here is the specs on the subs
Legacy LFW12X
Power (peak) 500Watts
Nom.Impedance 4
Voice coil 1.5
Magnet Structure 80
Fs(Hz) 45.4
Qms 1.55
Qes 0.87
Qts0.56
SPL9dB 89.0
Vas (cu. ft) 1.745
Can you tell me the formula to figure this out it will do me no good if you tell me the correct length for the subs. If I need more info on the subs can you tell me how to find that as well as thats all that came with the sub.
Also will this help me have a better sounding box or am I waisting my time GRIN
Replies (6)
Swez on 08/8/2003 06:24:28
Baine,
Personally, BP boxes are great for high SPL Comps if they are tuned and fitted to the sub properly. Unfortunately, most off the shelf BP boxes are just so generic that it is difficult to get the right fit. What you get at most stores is a "ONE NOTE WONDER" .
Read this:
Note: Many bandpass boxes are designed to produce a single note with a lot of gain. This means that there will be a peak in the output at that single frequency but the rest of the spectrum suffers. These boxes might sell in the stores because the salesman knows what song/music will be the most impressive with the enclosure and woofer(s). What the customer doesn't realize is that the chances of getting truly good sound quality from an enclosure with such a sharp peak in its output is nearly impossible. Using that type of enclosure produces the type of system that can only play one or two notes loudly. http://www.eatel.net/~amptech/elecdisc/spboxnew2.htm
May I frankly suggest you consider making/buying a sealed or ported enclosure instead? You'll get back some trunk space and cut weight as well... depending on how large that box is now.
NOT HARD TO MAKE A SEALED BOX EITHER... IF YOU HAVE SOME BASIC WOOD WORKING SKILLS AND TOOLS OR A BUDDY THAT DOES TO HELP.
Swez
baine on 08/8/2003 08:22:38
I plan on building a sealed box but, i want to sell this box (the only way i can get diffrent subs the wife says) if it dose not haxe the appeal that says buy the it will be hard to sell. Thats why i want to try to tune the ports for the subs that are in it :-)
Tray on 08/8/2003 09:03:07
With the investment you are going to have to make to get it tuned 'properly', you may just be better off trying to be realistic about it.
In order to tune it 'properly', you are going to have to replace the missing port, and possibly all of them. Cheapest way is to buy some PVC the same diameter as the box cutouts, and try different lengths until you find a sound you are happy with. Then some silicone to seal the ports in place, and it is 'tuned'.
Opportunity cost is the biggest burden in this equation. Will the end result (additional $$ attained by sale of 'tuned' box) outweigh the investment (your time + materials to tune). Basically I'm saying that if you can sell the box now for $100, is it worth spending $20 and 8 hours to sell the box for $125 later?
I completely understand the decision by the wife (commonly referred to as "The Pentagon", "The board of directors", "Mrs. Steinbrenner", in my household), and I'm sure you want to attain the most possible from sale of your current equipment, but I'm just offering some advice, as many of us have been in your same situation.
baine on 08/8/2003 10:14:44
Ok I should at least replace the missing port though (right?)
I understand my wifes decsion but what I do not understand is that she can waist money on fabric and Coka cola and I get sell your other one.. I need to get a second job to do what I want and she prob will still tell me how to spend it . Sorry just venting ...lol
Swez on 08/8/2003 11:40:11
Actually, your wife may be the better money manager in this case. Her argument is well founded and even though you mat think she is just wasting money on piddily stuff, everone in the house benefits from her efforts.
Ever heard the saying... if Momma ain't happy, den nobody happy! It's true... a fact of life. Yeah, you can vent safely here... but see what kind of tuning tubes are in the box now. If you can fabricate one to match.. OK, it will sell better as it looks better.
Youcan also pull the subs out and just sell the box as is for what ever yo can get. Use the subs you have now in a new box and when you can afford better subs, then upgrade. Just make the box close to 1.0 cf (internal) per sub (assuming 12's) Then, when you get your Infinity subs, they drop right in and add some poly fill to get the low bass you are missing now.
Comments?
Swez
baine on 08/8/2003 17:56:07
ok I will have to take your word on the money thing .. I don't see it. I get a 122 dollar check ever other week for a garnishment I have put on someone I got in to a wreck with in my truck. The first check I got I was going to buy some new tools as I was working on the starter and have cheap tools. I signed the check ( my first mistake) and left it on the counter and went to work , called at lunch to see what was going on and she had been shopping..... FOR HER AND MY SON spent most of it droped the rest in the bank and woops what about the guys whos truck got wrecked nada nothing .... Thats wrong In my opinion. Granted the truck is a 79 chevy 4x4 and all I needed to do was get a bumper and fix some minor stuff ( starter breaks and ball joint ) and its all done now but still. .......Still venting
I do agree that I should sell the box and my boss wants a new system in his 95 suburban (I told him I would charge him 20 bucks per item I put in he tells me I will do it for free) He is looking for a deck and I want a new one so I will see if I can get him to buy the box with cheap subs and my old deck for 200. All he will have to buy more is a amp I will tell him to get a crap one :-) Sorry is that wrong of me to do ??? ( they sound allright but not what I want)
Legacy LFW12X
Power (peak) 500Watts
Nom.Impedance 4
Voice coil 1.5
Magnet Structure 80
Fs(Hz) 45.4
Qms 1.55
Qes 0.87
Qts0.56
SPL9dB 89.0
Vas (cu. ft) 1.745
Can you tell me the formula to figure this out it will do me no good if you tell me the correct length for the subs. If I need more info on the subs can you tell me how to find that as well as thats all that came with the sub.
Also will this help me have a better sounding box or am I waisting my time GRIN
Replies (6)
Swez on 08/8/2003 06:24:28
Baine,
Personally, BP boxes are great for high SPL Comps if they are tuned and fitted to the sub properly. Unfortunately, most off the shelf BP boxes are just so generic that it is difficult to get the right fit. What you get at most stores is a "ONE NOTE WONDER" .
Read this:
Note: Many bandpass boxes are designed to produce a single note with a lot of gain. This means that there will be a peak in the output at that single frequency but the rest of the spectrum suffers. These boxes might sell in the stores because the salesman knows what song/music will be the most impressive with the enclosure and woofer(s). What the customer doesn't realize is that the chances of getting truly good sound quality from an enclosure with such a sharp peak in its output is nearly impossible. Using that type of enclosure produces the type of system that can only play one or two notes loudly. http://www.eatel.net/~amptech/elecdisc/spboxnew2.htm
May I frankly suggest you consider making/buying a sealed or ported enclosure instead? You'll get back some trunk space and cut weight as well... depending on how large that box is now.
NOT HARD TO MAKE A SEALED BOX EITHER... IF YOU HAVE SOME BASIC WOOD WORKING SKILLS AND TOOLS OR A BUDDY THAT DOES TO HELP.
Swez
baine on 08/8/2003 08:22:38
I plan on building a sealed box but, i want to sell this box (the only way i can get diffrent subs the wife says) if it dose not haxe the appeal that says buy the it will be hard to sell. Thats why i want to try to tune the ports for the subs that are in it :-)
Tray on 08/8/2003 09:03:07
With the investment you are going to have to make to get it tuned 'properly', you may just be better off trying to be realistic about it.
In order to tune it 'properly', you are going to have to replace the missing port, and possibly all of them. Cheapest way is to buy some PVC the same diameter as the box cutouts, and try different lengths until you find a sound you are happy with. Then some silicone to seal the ports in place, and it is 'tuned'.
Opportunity cost is the biggest burden in this equation. Will the end result (additional $$ attained by sale of 'tuned' box) outweigh the investment (your time + materials to tune). Basically I'm saying that if you can sell the box now for $100, is it worth spending $20 and 8 hours to sell the box for $125 later?
I completely understand the decision by the wife (commonly referred to as "The Pentagon", "The board of directors", "Mrs. Steinbrenner", in my household), and I'm sure you want to attain the most possible from sale of your current equipment, but I'm just offering some advice, as many of us have been in your same situation.
baine on 08/8/2003 10:14:44
Ok I should at least replace the missing port though (right?)
I understand my wifes decsion but what I do not understand is that she can waist money on fabric and Coka cola and I get sell your other one.. I need to get a second job to do what I want and she prob will still tell me how to spend it . Sorry just venting ...lol
Swez on 08/8/2003 11:40:11
Actually, your wife may be the better money manager in this case. Her argument is well founded and even though you mat think she is just wasting money on piddily stuff, everone in the house benefits from her efforts.
Ever heard the saying... if Momma ain't happy, den nobody happy! It's true... a fact of life. Yeah, you can vent safely here... but see what kind of tuning tubes are in the box now. If you can fabricate one to match.. OK, it will sell better as it looks better.
Youcan also pull the subs out and just sell the box as is for what ever yo can get. Use the subs you have now in a new box and when you can afford better subs, then upgrade. Just make the box close to 1.0 cf (internal) per sub (assuming 12's) Then, when you get your Infinity subs, they drop right in and add some poly fill to get the low bass you are missing now.
Comments?
Swez
baine on 08/8/2003 17:56:07
ok I will have to take your word on the money thing .. I don't see it. I get a 122 dollar check ever other week for a garnishment I have put on someone I got in to a wreck with in my truck. The first check I got I was going to buy some new tools as I was working on the starter and have cheap tools. I signed the check ( my first mistake) and left it on the counter and went to work , called at lunch to see what was going on and she had been shopping..... FOR HER AND MY SON spent most of it droped the rest in the bank and woops what about the guys whos truck got wrecked nada nothing .... Thats wrong In my opinion. Granted the truck is a 79 chevy 4x4 and all I needed to do was get a bumper and fix some minor stuff ( starter breaks and ball joint ) and its all done now but still. .......Still venting
I do agree that I should sell the box and my boss wants a new system in his 95 suburban (I told him I would charge him 20 bucks per item I put in he tells me I will do it for free) He is looking for a deck and I want a new one so I will see if I can get him to buy the box with cheap subs and my old deck for 200. All he will have to buy more is a amp I will tell him to get a crap one :-) Sorry is that wrong of me to do ??? ( they sound allright but not what I want)
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