hey guys, couple questions need help with

first off, friend gots 2 JL 12w1-8 subs, there 8ohms and he has a 2 channel rockford amp thats rated at 4ohms,

now if i bridge the amp and run the 2 subs there, that should be a 4 ohm load for the amp right? or does bridging the amp change the ohm....

second off, one thing that i can never find absolutly anywhere is what the freq. on an amp does and changes or how to set it properly, so any help, litterly, would be a big help

and there was a video somewhere on the net as to how to set an amp with a multimeter if anyone has a link to it by any chance

thanks for the help smile.gif

 

it all depends. if you have 2 8 ohm loads in paralell, yes it will be a 4 ohm load. You may want to check to make sure that they're not Dual Voice coil speakers that can be configured to be 2-4-8 ohm speakers. You can check the ohm load with a multimeter once you hook up the voice coils.

BTW... there are not too many car audio speakers out there rated for 8 ohms. Usually they're 4 ohm or 2 ohm because you get better sound quality out of 2-4 and more bounce for the ounce of power for 8 ohm. A 8 ohm speaker probly wouldn't sound too great in a car. You should look at using different speakers.

 

there not my subs, and they dont sound to great lol, always getting compliments on how my 1 12" infinity sounds 100x better then those 2 JL's

i made sure that they wernt DVC when i wired them up, and yes i got them running in parallel

 

It is unusual to have an 8ohm car speaker with a single coil. But, I do know that JL's 8 inch drivers were designed to be ran in cofigurations of 3 and 4 and above. So that would make sense.

Now, they certainly shouldnt sound shit because a friend of mine had 3 of the old W6 woofers (the ones that look like the more modern w0 and so on) and they were astounding for such small woofers.

I do know that the JL 8's need *tiny* enclosures and you shouldnt run them ported as woofers that small are better kept still and tight.

Running 2 8ohm speakers will make the amp see a 4ohm load yes, so you should be ok there but I would check a few things if it sounds shit.

#1 make sure the enclosure is 100% right down to the last cubic inch.
#2 DO NOT cross them over too low, they will quack and fart. Get the spec sheet from JL's site and make sure you have them crossed over at the right frequency and cut off anything lower. They will climb pretty high in the spectrum so you also want to limit the upper frequency level that is being fed to them.
#3 if needs be get a good active crossover or at least some kind of passive crossover for them, dont feed them a full range signal or theyre bound to sound crap.

Oh and what head unit does he have? please dont say sony or jvc because thats the problem

 

yeah, the frequency adjustments on amps are high or low pass filters. if the amp is primarily a sub amp, it should only have a low pass filter. what you want to do is check the mfr's specs on the subs frequency range, and then set the low pass filter for the upper value where the sub reaches its limit.

but you have subs these days that will usually produce sound pretty good above the highest setting for the low pass filter, so just adjust it until you like the sound.

the filter simply limits what sounds will get to the sub. the higher the frequency, the higher the sound.

 

^^ yeah. Hz (hertz) is how many times the speaker can vibrate per seccond. Typically you want to keep the setting below 400 hz for subs. With a good 12" you can usually set it to 300 and be alright.

Basically that's used for tuning. You setup your sub and amp, turn your music on loud, and play with the gain and frequency until it sounds good.





There's more professional ways of doing it with expensive setups that will measure distortion, but that's the parking-lot installer's method.

 

sweet thanks alot guys, ill be sure to definitly check that all out

i have his amp set for low pass so that did make it sound abit better then before and i rewired his HU and settings and all so they sound crapload better but still not really there

and funny thing, he has a JVC HU lmao.gif

turns out he spent $350 on it and when i did the wiring up yesterday i noticed it didnt even have a sub out, so he had it running as rear speakers, after he saw this out he ended up buying a new HU with me on boxing day, that pioneer 6800,

made my car sound alot better then my older clarion deck, but he drives a golf so im gona do his HU later on since there cars are assembled in the dumbest way that it takes 100x longer then normal to do a simple task

so well see then if it made a change

thanks for the help guys smile.gif fing02.gif