How close does a line driver need to be?

[Bchester6]

rear installed line drivers= worthless

[ttocs]

If someone's system is louder with a line driver than without, then they are likely just using the line driver to send an amplifier further into clipping, or they did not have the gain properly set prior to installing the line driver.

I have to respectfully disagree with you guys, though your theory is spot on. I don't go driving around listening to sine waves though. I had an ipod w/ lossless files going straight to my amps for a while. Technically, the ipod output signal was capable of driving the amps to full power no problem. There were countless records that were nowhere near loud enough for me though, and were certainly not pushing my amps close to max. Added a gain stage in the way of an eq, problem solved. Will things clip with a source that peaks just before 0db now? Probably. I have a volume nob and I know how to use it though. Just saying, quoted output voltages mean nothing without defining your source/input signal. I agree with the not putting it in the back part though, that just doesn't make sense.

This is also not what the line driver is made for but can be used for. I also used one once to wire the rca's outputs to a headphone jack so he could listen to the music on his headphones while his wife was sleeping. Again not what its made for but it can work.

again in a perfect world there would be no noise in stereo signal and your lossless ipod would be a perfect signal but in the real world what happens and "technically "what happens, isn't always the same thing even when they are....

[LowandLoud]

Putting a line driver inside an amplifier is high on the list of useless features for an amplifier. Installing a line driver is not to make your system louder, it is to reduce the noise floor that exists on the long (often 16ft or so) RCA cables from the front of the vehicle to the rear.

The RCA cable will pick up some amount of nose. If you only have 2V of signal on it, the ratio of noise will be higher than if you have 8V on it.

A system with a 2V head unit and a quality amplifier should be just as loud as a system with an 8V line driver installed, and that same amplifier, the difference being there will be a lot less noise (hiss for example) in the quiet portions of music on the 8V line driver equipped setup.

If you install an 8V line driver in the rear of the vehicle (after those 16ft RCA cables), then your system will be no louder, and have just as much noise as the 2V head unit system would have. In this case the line driver would be serving no real purpose, as it would be boosting the noise that has gathered up on the RCA.



If someone's system is louder with a line driver than without, then they are likely just using the line driver to send an amplifier further into clipping, or they did not have the gain properly set prior to installing the line driver.

Makes perfect sense. Thank you

LL

[vwdude]

hey guys thanks for the responses. sorry for my delayed response, I was on vacation and didnt have cell signal.

so heres my scenario, factory deck, running speaker level to the rear of the car, where it hooks up to a JBL MS-8. as been stated earlier in this thread, MS-8 gives a 2.5v signal. ZPAs need 8v signal (and my gains are kind of high for what I would expect on these amps). The noise floor is also kind of high (result from higher gains? maybe higher volume on the deck?)

So technically I am running a balanced signal to the rear, and I have only a few feet from the processor to the amps. I will still put the line driver within 18 inches of the processor, but it will be in the back.

oh, and I make my own RCAs. I am making new ones for this install, and i am using high end mic cable that is shielded and twisted.

[groundpounder]

I don't know what factory deck you have? But in my opinion, SQ starts with the head unit and your sound system is only as good as your weakest point. First I would invest in a good quality head unit, and then put the line driver as close to it as possible.

[ttocs]

putting the EQ processor in the back of the car is the same thing as putting the line driver there. I am willing to bet you look into the manual and somewhere it will suggest putting it as close to the signal as possible. If the eq is back there then it will not matter if the line driver is back there.

[LowandLoud]

But he is running line level to RCA most likely off of a rear speaker. Thats why he cannot put it closer to the H/U. Some new cars make it a real pain to use an aftermarket H/U. Im not sure it would even help in this situation?

LL

[vwdude]

First off I have the RNS-315 for anyone who knows about modern VW head units. It had Nav, Bluetooth, and is integrated with the climate controls. These units have been tested and give an unmolested signal out.

I am running speaker cable from the front to the rear, but from my understanding, speaker level is balanced and therefore wouldn't suffer the degredation that RCA level does.

[ttocs]

unless the amp is in the back of the car there is no reason the signal can't be tapped up front and it will be a cleaner signal there having not gone through all the other powered systems where it gains noise into the signal. Same thing is recommended with a LOC that you tap the signal AS CLOSE TO THE SOURCE AS POSSIBLE and for one reason only, to get it before the noise gets in. EQ, line driver, tomato-tomato. Tapping the signal in the back of the car for any of these pieces will mean that you are probably sending the noise it has gained into your amplified system meaning it gets amplified, just like the signal.

Speaker levels are not balanced and they don't suffer signal problems until you take it, knock it down to low level rca(after the noise is in), process it and then amplify it. If it isn't fed into another amp, the way its designed to be used, then no it doesn't suffer as bad as an RCA signal that HAS to be amplified.

[vwdude]

Thanks for the info ttocs. I'm not suffering from any excessive noise issues and the ms-8 is way too big to fit up front anyways.

Ok so I think I have my information. Thanks for the help everyone.

[ttocs]

under a seat maybe? I know its big in a dash and hard to fit up there but every foot closer to your source will be a foot closer to a cleaner signal. MS8 can do some neat stuff except make a nice output from a shitty input.