Bought 2 RE audio 18 SX's....... and....

[knowledgestick 10+ year member]

You have to decide what ohm you are actually at. Earlier, you said each sub is 1 ohm, now you say ther are dual 4... pick one. If they are dual 4, wire each positive to positive and neg to neg on each sub, then you have 1 pos and 1 neg coming from each sub, wire pos to pos and neg to neg, and you have a TOTAL 1 ohm load, which is what your amp wants to see for max power.

i think you are reading to fast and not paying attention.

i have said from the start that my subwoofers are d4's.

i am not sure if they are at 1ohm or 2ohm's, i tested them at the amplifier on the last video i showed and they come up as 1 ohm each woofer, now would that make the load on the amplifier 2ohm ?

this is how the diagram says my woofers should be wired up, but they are not.

they are wired seperately as one member stated, who was actually paying attention. If the amplifier is indeed at 2ohms and only putting out around 550rms to each subwoofer, and then having the gain being turned all the way up be the only way the system gets loud makes sense, now lets not go backwards.

How can you wire up subwoofers like this with so many connection points what type of wiring is that shown in the diagram is looks to have multiple connection points ?

i think the problem here, is the fact that my amplifier is clipping the subwoofers because they are at 2ohm, and i have to turn the gain up so high to get any deciant thump out of them.

Now please, if you dont think this to be the reason then dont post as to why, please help me figure out how to wire thease subwoofers at 1ohm, or if infact they are already at 1ohm.

watch this video for testing with metre & to see how subwoofers are wired up currently : http://blip.tv/file/1988262

 

[Bassman999 10+ year member]

yes your amp is running at a 2 ohm load which from the amps specs is 1300rms then factor in that they are slightly overrated so your probably giving your subs 500rms each clipped bad. Your subs are dual 2 ohm and you won't be able to run them at 1 ohm


Yes HIS box has 100^2 of port area. However I took his dimensions and designed a normal rectangle box with a slot port and after port displacement I came out with 8.6 cu ft tuned to 30hz. He stated that his box is tuned to 29-30hz so I designed an enclosure that would be around what his should be.

ok, i gotcha.

 

[Bassman999 10+ year member]

You have to decide what ohm you are actually at. Earlier, you said each sub is 1 ohm, now you say ther are dual 4... pick one. If they are dual 4, wire each positive to positive and neg to neg on each sub, then you have 1 pos and 1 neg coming from each sub, wire pos to pos and neg to neg, and you have a TOTAL 1 ohm load, which is what your amp wants to see for max power.

he is at 1 ohm, that amp has 2 sets of outputs that are paralleled together as one so he sees (2) 1 ohm loads, but it is all one load really.

 

[brian84corvette 10+ year member]

I got a sx 18 in my vette right now.

its pretty musical up to a point. then its just spl baised dirty loud.

never been on a meter with it, but id cry if I wasnt well in to 140's

 

[knowledgestick 10+ year member]

he is at 1 ohm, that amp has 2 sets of outputs that are paralleled together as one so he sees (2) 1 ohm loads, but it is all one load really.

are you 100% sure that the amplifier load is 1ohm ?

what else could explain the fact that the amplifier seems so weak when the gain isnt cranked right up?

this leads back to the capacitor, if indeed the load is at 1ohm, could it be because the amplifier is getting its power from the capacitor, witch is hooked up to my kinetik hc 1800 upfront ?

if so, this problem would be easily remedyed by placing in my hc2000 beside the amplifier and giving it the propper power it needs.

If it is infact at 1ohm, then this is the only thing i can think of that is contributing to the exessive thermal build-up, is the fact that the 1 farad capacitor cant juice up the amplifier enough to push out the RMS it states it can at 1ohm, thus me having to crank the gain up and begin to clip the amp. I have another kinetik battery as mentioned, a hc 2000. I could have this wired up beside the box, and run directly to the amp witch would be alot more power than the little capacitor, i just didnt have the cash to get it done with the innitial box re-build. It will be wired up with the battery i have upfront witch is a kinetik hc 1800.

again here's the video.

http://blip.tv/file/1988262

and BTW i am almost 100% positive my box is not 8 cubic feet, i built a subwoofer box with that specs for my single remaining ma audio subwoofer and the box in my trunk is larger than that, It is atleast 10 cubic feet after woofers and all.

So again, if it is at 1ohm right now the amplifier is not putting out much juice until the gain is cranked, could this be because the capacitor beside the amplifier running it, is not giving the amplifier enough power to turn over that much RMS ?

so there for, when i play it with the gain where it should be it is sounding alot more quiet than it should, because it is not getting enough juice ?

this is my last standing theory, i dont think the box alone is contributing to such over-heating issues, i think the amplifier clipping because the gain is full is the reason, now i have to figure out why my amp is so quiet unless the gain is cranked.

 

[brian84corvette 10+ year member]

what is your rca wire voltage ? you may want to try out a thing called a line driver

wich is ajustable that can increase the signal strength in your rca wires to the amp.

it helped me out a ton.

I have crappy sony headunit = .5v to the rca wires. amps like about 4 to 7 volts on rca wires

and can then turn the gain down a bunch to make up for increased signal strength.

 

[knowledgestick 10+ year member]

what is your rca wire voltage ? you may want to try out a thing called a line driverwich is ajustable that can increase the signal strength in your rca wires to the amp.

it helped me out a ton.

I have crappy sony headunit = .5v to the rca wires. amps like about 4 to 7 volts on rca wires

and can then turn the gain down a bunch to make up for increased signal strength.

my pre-out amprage from the head-unit is suposed to be 2.2v, Also would a line-driver make that big of a differance since my head-unit doesnt have as bad of a voltage as yours ?

you guys dont think it could have anything to do with the capacitor being the main power-source for the amp ?

Do any of you think if it was replaced the amplifier would put out alot more power and sound louder, and in turn let me turn the level setting down because right now maybe the amplifier is in a way choked up from the capacitor and cant get enough power to create the RMS thease woofers need, and when i turn the gain up so high it clips them, and creates the over-heating.

just my theory...

also could my RCA cables be crappy quality or somthing ?

 

[snfsh79077 10+ year member]

my subwoofers are dual 4 ohm i had them designed so i could run them at 1ohm.

Your subs cant be dual 4 ohm if they are reading 1ohm each.

You have to decide what ohm you are actually at. Earlier, you said each sub is 1 ohm, now you say ther are dual 4... pick one. If they are dual 4, wire each positive to positive and neg to neg on each sub, then you have 1 pos and 1 neg coming from each sub, wire pos to pos and neg to neg, and you have a TOTAL 1 ohm load, which is what your amp wants to see for max power.

x2

 

[snfsh79077 10+ year member]

are you 100% sure that the amplifier load is 1ohm ?
what else could explain the fact that the amplifier seems so weak when the gain isnt cranked right up?

this leads back to the capacitor, if indeed the load is at 1ohm, could it be because the amplifier is getting its power from the capacitor, witch is hooked up to my kinetik hc 1800 upfront ?

if so, this problem would be easily remedyed by placing in my hc2000 beside the amplifier and giving it the propper power it needs.

If it is infact at 1ohm, then this is the only thing i can think of that is contributing to the exessive thermal build-up, is the fact that the 1 farad capacitor cant juice up the amplifier enough to push out the RMS it states it can at 1ohm, thus me having to crank the gain up and begin to clip the amp. I have another kinetik battery as mentioned, a hc 2000. I could have this wired up beside the box, and run directly to the amp witch would be alot more power than the little capacitor, i just didnt have the cash to get it done with the innitial box re-build. It will be wired up with the battery i have upfront witch is a kinetik hc 1800.

again here's the video.

http://blip.tv/file/1988262

and BTW i am almost 100% positive my box is not 8 cubic feet, i built a subwoofer box with that specs for my single remaining ma audio subwoofer and the box in my trunk is larger than that, It is atleast 10 cubic feet after woofers and all.

So again, if it is at 1ohm right now the amplifier is not putting out much juice until the gain is cranked, could this be because the capacitor beside the amplifier running it, is not giving the amplifier enough power to turn over that much RMS ?

so there for, when i play it with the gain where it should be it is sounding alot more quiet than it should, because it is not getting enough juice ?

this is my last standing theory, i dont think the box alone is contributing to such over-heating issues, i think the amplifier clipping because the gain is full is the reason, now i have to figure out why my amp is so quiet unless the gain is cranked.

ok first off get rid of the cap. Install the hc2000 in the back with at least 2 runs of 0 gauge from the front bat to the back bat. Then hook the amps + and ground to the back bat. Then set your gains with a dmm and rewire your subs so you are positive they are correct. Just make it to where you only have one wire going to the amp from the subs. After all that is done check your voltage drops, you may need a HO alt (cant remember if you already had one). A sufficient electrical is critical.

After all of that is done and you are still not happy then buy a line driver, install it, and reset your amp with a dmm. After all of that is done we can go from there. Until then there are still many factors that can be the cause.

As for the size of your box. Just because your box looks like its 10 cubes or bigger doesn't mean it is. I stand by my statement that your box is not as big as you think it is. I'm not saying its 8.6 cubes but it is most likely close to it. Your box does not have the proper amount of port area which is going to cause a problem. The best way to get a def measure on your box is take packing peanuts and fill the box up. Then gradually take them out measuring 1 cubic foot at a time.

 

[Bassman999 10+ year member]

ok first off get rid of the cap. Install the hc2000 in the back with at least 2 runs of 0 gauge from the front bat to the back bat. Then hook the amps + and ground to the back bat. Then set your gains with a dmm and rewire your subs so you are positive they are correct. Just make it to where you only have one wire going to the amp from the subs. After all that is done check your voltage drops, you may need a HO alt (cant remember if you already had one). A sufficient electrical is critical.
After all of that is done and you are still not happy then buy a line driver, install it, and reset your amp with a dmm. After all of that is done we can go from there. Until then there are still many factors that can be the cause.

As for the size of your box. Just because your box looks like its 10 cubes or bigger doesn't mean it is. I stand by my statement that your box is not as big as you think it is. I'm not saying its 8.6 cubes but it is most likely close to it. Your box does not have the proper amount of port area which is going to cause a problem. The best way to get a def measure on your box is take packing peanuts and fill the box up. Then gradually take them out measuring 1 cubic foot at a time.

Thats a lot of pkg peanuts, but it is the only way to be 100% positive of the Exact volume. yeah I had that same amp and it just has 2 outputs that are really one internally.

Knowledge stick just unhook one side from one speaker wire from amp, and prove this by reading 2 ohms on any + or - speaker terminals

 

[knowledgestick 10+ year member]

Thats a lot of pkg peanuts, but it is the only way to be 100% positive of the Exact volume. yeah I had that same amp and it just has 2 outputs that are really one internally.
Knowledge stick just unhook one side from one speaker wire from amp, and prove this by reading 2 ohms on any + or - speaker terminals

if you guys want to go back and watch the video of me unwrapping thease woofers they are d4's.

sorry bassman, i dont quite understand what you mean you want me to unhook a wire from the amplifier and then read the amplifier and see if it reads at 2ohms ?

 

[snfsh79077 10+ year member]

Thats a lot of pkg peanuts, but it is the only way to be 100% positive of the Exact volume. yeah I had that same amp and it just has 2 outputs that are really one internally.
Knowledge stick just unhook one side from one speaker wire from amp, and prove this by reading 2 ohms on any + or - speaker terminals

yea it will be a lot of peanuts but its the only way really.

I had stated I think his amp was at a 2 ohm load just because I wasn't sure how the outputs were on that amp. Thanks for clearing it up though.

 

[Bassman999 10+ year member]

if you guys want to go back and watch the video of me unwrapping thease woofers they are d4's.
sorry bassman, i dont quite understand what you mean you want me to unhook a wire from the amplifier and then read the amplifier and see if it reads at 2ohms ?

u have others confused saying each speaker reads 1 ohm at amp. in actuality u r reading total impedance(ohms) on each sub. the amp is one channel, so the impedance will read 1 ohm on either set out spkr oputputs. disconnecting one wire would make impedance 2 ohms to prove that.

 

[snfsh79077 10+ year member]

if you guys want to go back and watch the video of me unwrapping thease woofers they are d4's.
sorry bassman, i dont quite understand what you mean you want me to unhook a wire from the amplifier and then read the amplifier and see if it reads at 2ohms ?

I remember when you unpacked them I just became confused when you tested each speaker and they came out 1 ohm each. This was just a misunderstanding of how the amps outputs work which was cleared up by bassman.

All he wants you to do is unhook one speaker front he amp then test the speaker you unhook with the dmm showing that it is indeed at a 2ohm load.

 

[Bassman999 10+ year member]

knowledgestick, I cant remember who said it, but You would have better results from reconing your subs as 15's and then making a larger port and adding some bracing to the box and refacing the box for 15" subs. You could also sell the sx's and get some different subs in 15's . Just a possiblilty, maybe something like treo ssx or Audioque hdc3