brute power or line drive?
 

ive spent the last 20 minutes re-wringing my question so it would make sense. SO: WILL A LINE INCREASE ACTUAL DBs?

if im only increasing the input voltage/signal from my HU and not the current/power delivered from my battery, why does it make it seem like it is louder?

example, i had my gains set to almost .5v (very high i know) w/ bass boost at 1/4 and still i could not get full output of my driver. with the line driver installed and set just below 1/2 way i can now turn my gain and bass boost to a closed position and get a greater output from my driver. (still needs to be tuned)

If a head unit outputs enough voltage to drive the amp to full output then a line driver will not improve things. Some head units may have some sort of output clipping detection on the built in pa chip and lower the dac level. (stock radios have this alot!) Increasing bass boost will influence this. Perhaps your levels where not setup properly. But great that adding a line driver helped.

your SPL should not change.

Because you are increasing the power delivery.

The amplifier takes the signal from the HU and..... wait for it.... amplifies it.

Crank your gains and you won't need to turn it up as much, keep your gains low and it won't be as loud because there isn't as much signal voltage to amplify.

Really all you're doing when you adjust the gain is, in a way, adjusting at what point in your volume clicks the amplifier gets maxed out.

The down side is you start to push the amp too hard with the gains and it can no longer produce a clean signal. Then things start to fry.

*my compltely non-technical answer btw.. I'll let the egg-heads here get in to more detail if they choose ;)

thanks a lot guys. i still think im going to leave it installed for a while. it gives the driver a different tone which i hated at first but absolutely love now. not to mention the extra output!

note: i did try maxing out my sub/amp a while back and no matter what i did to my HU setting, amp settings or wiring configuration of the sub i never gained anything noticeable. i got a HUGE output gain with the line driver.(with amp gains as low as i can set)

come by for some termlab reading

using a line driver is a good way to boost your headunit signal. If your deck output is un-clipped, and the line driver can boost that signal while maintaining un-clipped output, your amp will need to boost that signal less "maintaining non-clipp". Your spl should be maintained or improve due to the cleaner output.

Sometimes, mild clipping yields spl gains....you can never predict the outcome either way unless you test with termlab. Take Yuli's offer, could save you alot of confusion!

EX: i tested my car last week and had a woofer failure. headunit was throwing noise and once amplified, that noise caused output amperage to double, cooking coils without hesitation....you have to know your signal is clean and controlled.

thanks bart. i did pm Yuli and were working some things out. i understand what you are saying which is making me think that maybe i can get more output from a much cleaner signal which would explain the tone difference in my woofer. i have my my 15 inch driver in a rather small box since i knew/thought the line driver would be able to push my driver past its limits and with a smaller box for better dampening to the woofer (2.5 internal tuned around 37hz)

basically what Bart said, cleaner signal will sound better. output wise, there should not be any difference unless you have a deck from like 1982.

i do have a weak HU sony CDX-GT930U1 which is only 2.4v pre outs. i just walked my dogs and brought my line driver up so i can turn it down a bit. YULI, when are you free?