I have an 18 Bl and Saz-1500d. There was a topic about this (not for sure if it was on this site actually), that i planned on referring to when it came down to installing, but i can't seem to find it anywhere. SO here's what i think im supposed to do, and if anyone could add/correct/verify this, please do.

Set subsonic, LPf to where i plan to have them regularly. Set bass boost to zero, and gain to minimum.

Get a sine test (60 hz? (would a loud 'music' cd work?)) and adjust the gains untill audible clipping occurs, and then back down a little. Doing all this with volume 3/4.

Does that sound right? I'm 16, and this is my first setup (not system, because i cant afford mids highs yet ) and like i've said before, there's really no one for me to learn from where i live... my local shop wouldn't help (not that i'd really trust them anyways) because i didn't buy their Jl/mtx products, lol.

Thanks to everyone that took the time to read this and reply,

Mitch

Sounds ok to me.

I'm not sure how noticeable is clipping at those frequencies though

50hz is where most set by ear. and you need the sine wave. music is dynamic, so it fluxates too greatly to be done right. also, use a 0 to -3db tone. depending upon who you talk to, you'll get different answers on why to use the 0db or the -3db tone. some prefer teh 0db due to the fact it'll provide a cushion compared to music, where others will argue the -3db is more accurate or closely relates to the peakiness of music. (or some shit like that, lol. i'd have to look that up)

one thing....3/4 volume on the headunit is like 3/4 gain on the amp. it's a guess. you don't want the h/u clipping either. get a 1khz test tone, play through the h/u and speakers, not sub. turn it up till you hear the tone change. that's your h/u clipping. set you sub gains with the h/u turned up to the point just before clipping. of course you'll have to reset once you amp your high side and finish the system.

otherwise, what you have described is the accepted way of setting by ear.

wheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee

Thanks for the replies, but one more thing. i think i remember seeing that i should set my EQs flat on the h/u. I don't really see why i would if that's not going to be how i actually listen to it, or is that wrong?

Thanks for the replies, but one more thing. i think i remember seeing that i should set my EQs flat on the h/u. I don't really see why i would if that's not going to be how i actually listen to it, or is that wrong?

You should set the eq and bass boost to where you think you are going to use them.

Suppose you set everything flat, set the gains and then add 5dB of bass boost. You will get a clipped signal around the boost earlier than the rest of the spectrum.

You should also step away from the vehicle when you test because you can hear distortion a lot better from farther away than right up close to the sub. Also, don't only base your opinion on distortion, as it can be difficult to hear at low levels and some subs are pretty good at masking it. Another thing I look for is when the sub stops getting louder, and if you go back and look at the sub it has stopped moving out any farther (note: this last one is obviously frequency and box dependent. If you play a 30 hz tone on a box tuned to 30 hz it may take 5000 watts to get it to move fully, while it may only take 10 watts to make it move fully in that same box at 10 hz. sealed boxes are better for this.)

http://mobile.jlaudio.com/support_pages.php?page_id=143

you don't want the h/u clipping either. get a 1khz test tone, play through the h/u and speakers, not sub. turn it up till you hear the tone change. that's your h/u clipping. set you sub gains with the h/u turned up to the point just before clipping. of course you'll have to reset once you amp your high side and finish the system.

Problem is that the HU amp starts to distort horribly before it clips. I've seen as much as 10% THD before clipping in tests. The preouts should be nowhere near clipping or distorting at all at this point. I'd wager that if you turn the HU up to where the internal amp starts to audibly distort, the sub preout will be weak enough that you'll have to set the gains pretty high.