# Line Out Converter vs. RCA Outputs on headunit



## user name unknown (Sep 2, 2001)

OK, here is the problem/scenario:
I used to have my subs and amp installed with the stock double-din monsoon headunit. To get RCA's to the amp, I used a line out converter and tapped into the wires at the Monsoon amp. It hit very hard.
Well, now I have a non-monsoon system so I installed a Blaupunkt Tampa Bay headunit. I figured I would just used the RCA outputs that come out of the back of the headunit to send the signal to my amp. Well, here is the problem I am having. The subs don't hit nearly as hard as they did when I had the signal set by the line out converter. It's like the signal that is being sent SUCKS! I don't understand how this could be.
I would like to get back my hard hitting bass like I had before. What can I do?


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## user name unknown (Sep 2, 2001)

*Re: Line Out Converter vs. RCA Outputs on headunit (user name unknown)*

ttt


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## DJKeebler (Dec 6, 2001)

*Re: Line Out Converter vs. RCA Outputs on headunit (user name unknown)*

You have to look at the voltage that the headunit is putting out for the preamps. 4 volts is pretty common these days but most of the older headunits and some of the current ones still go with small voltage amounts like 2.7 or less. 
An amp reads the voltage as a signal level. The higher the voltage being put out by a headunit, the more sensitive the amp will be. Also, the higher the voltage running to the amp, the lower you will be able to keep the amp sensitivity reducing the possibility of distortion and engine hum. The line-level converter probably had an adjustment on it that allowed you to turn the voltage level up and down. This is because the line-level converter needs to work with many different headunits and needs to have the voltage adjusted to work efficiently with an amp. Your Blaupunkt however has a fixed voltage level coming out of the pre-amps and this voltage may be lower than the line-level converter was. You should be able to turn up the sensitivity(Gain) on the amp to make up for loss of volume but just don't over do it. The proper way to set an amp level is to turn the amp sensitivity all the way down and turn the volume level on the headunit all the way up. Then http://****************.com/smile/emthup.gif slowly adjust the amp sensitivity turning it up until you get to the maximum volume you want or your speakers start to distort. When you get to this point, turn the volume on the headunit down all the way and then turn the sensitivity on the amp up 1/4 turn. Then listen to the system normally and turn the amp gain down if still experiencing distortion. I wouldn't turn it up at this point to make it louder. That will only clip the signal and cause distortion. If it's still not loud enough for you at this point, you may need more power or better speakers. 
If you need anything else, hit me up by IM or email and I can run through some stuff with you. Good luck!


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## user name unknown (Sep 2, 2001)

*Re: Line Out Converter vs. RCA Outputs on headunit (DJKeebler)*

Is there something I can buy that will increase the signal going over the RCA's?


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## genixia (Feb 8, 2002)

*Re: Line Out Converter vs. RCA Outputs on headunit (user name unknown)*

The stock head units have different codings for different car body shapes, eg Golf, Jetta, Passat etc. It's never been confirmed but many people have long suspected that this is principally to EQ the head unit to match the car's acoustics. Given that the stock system only has 6.5" woofers to provide all the bass and as much sub-bass as they can muster, it is not a stretch to imagine that this EQ might be bass heavy, and hence the reason why your previous set up bumped so much.
It is possible to buy pre-amplifiers, but they are harder to find (and usually more expensive) than an adjustable speaker->line level converter. You may want to consider running speaker level wires to the sub and placing a LOC nearby.


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## 2.ohh (Jun 21, 2002)

*Re: Line Out Converter vs. RCA Outputs on headunit (user name unknown)*


_Quote, originally posted by *user name unknown* »_Is there something I can buy that will increase the signal going over the RCA's?


get a line driver or a bass cube from phoenix gold. the line driver will only increase the signal up to usually 8 volts. the bass cube is a 1 band parametric equalizer with adjustment from 20-110 hz. it does not increase the signal, though.
is the problem just that there isn't as much low bass, or is the whole bass region? have you adjusted the gain properly on the amp? have you checked all the adjustments on the HU? i've seen people run a high pass x-over on their HU by accident to the sub RCA's.


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## user name unknown (Sep 2, 2001)

*Re: Line Out Converter vs. RCA Outputs on headunit (2.ohh)*


_Quote, originally posted by *2.ohh* »_is the problem just that there isn't as much low bass, or is the whole bass region? have you adjusted the gain properly on the amp? have you checked all the adjustments on the HU? i've seen people run a high pass x-over on their HU by accident to the sub RCA's.

I am running the RCA's from the right rear and left rear RCA outputs on the back of my Blaupunkt headunit. The problem is only with certain songs. When I used to listen to Slayer with my old LOC setup, it used to hit nice and hard. Now when I listen to the same Slayer CD with my current setup, there is hardly any bass. I mean there is some, but not nearly as much as there used to be. In order for me to get the bass that I would like, I would need to turn my headunit volume up a lot more. That is not an option because then my stock speakers wouldn't be able to handle that.
Do you think if I added my LOC onto the right and left rear positive and negative wires coming from the back of my Blaupunkt headunit that that would make a difference?


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## user name unknown (Sep 2, 2001)

*Re: Line Out Converter vs. RCA Outputs on headunit (user name unknown)*

anyone?


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## 2.ohh (Jun 21, 2002)

*Re: Line Out Converter vs. RCA Outputs on headunit (user name unknown)*

have you adjusted the gains on your amp?


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## genixia (Feb 8, 2002)

*Re: Line Out Converter vs. RCA Outputs on headunit (user name unknown)*

I don't remember seeing this asked before in the thread...
Have you double-checked your speaker polarities? A phase invertion would kill the bass.


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## VeeDoubleYouGuy (Nov 4, 2003)

*Re: Line Out Converter vs. RCA Outputs on headunit (genixia)*

also if you're listening to slayer then most of the bass is around 100-120 Hz. Does your deck have a variable crossover set too low?


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## user name unknown (Sep 2, 2001)

*Re: Line Out Converter vs. RCA Outputs on headunit (VeeDoubleYouGuy)*

I am not to familiar with what a variable crossover is.


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## adam_pdx (Feb 5, 2004)

*Re: Line Out Converter vs. RCA Outputs on headunit (user name unknown)*


_Quote, originally posted by *user name unknown* »_I am not to familiar with what a variable crossover is.

A variable crossover is the same as a non-variable crossover except that you can change the cut-off frequency. For example, on most HU's sub-out, you can select 50hz, 80hz, or 120hz; although, they may not indicate the "hz" on the readout. Then, at each cutoff frequency, there is usually a gain setting - most are +/- 6.
What I think *VeeDoubleYouGuy* is trying to ask is, is there a chance that the variable corssover is set to 50hz low-pass so that the higher frequency bass is not being passed to the speakers?
If there is this setting, Change it to a higher setting such as 120, or 150 (if it is an option) and see what you think.
If your HU has a built in EQ, try boosting the low frequency settings on that as well.


_Modified by adam_pdx at 3:44 PM 4-13-2004_


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## user name unknown (Sep 2, 2001)

*Re: Line Out Converter vs. RCA Outputs on headunit (adam_pdx)*

Ahhh...now I understand, but there is a problem.
1) My headunit doesn't have a built in EQ
2) I don't have sub pre-outs. I only have regular pre-outs.


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## adam_pdx (Feb 5, 2004)

*Re: Line Out Converter vs. RCA Outputs on headunit (user name unknown)*


_Quote, originally posted by *user name unknown* »_Ahhh...now I understand, but there is a problem.
1) My headunit doesn't have a built in EQ
2) I don't have sub pre-outs. I only have regular pre-outs.

Crossovers and EQ's are two distinctly different things.
If I read the thread correctly, you are using the RCA pre-outs to drive your sub amp, but you do not have sub-out pre-outs.
so my next logical guess would be to see if there is a built-in crossover on the front and rear pre-outs that is only passing high frequencies. Most of the time, the high pass crossover is set at 200hz. If you have this option, turn the HPF off.
Other than that, you could get an external EQ that has sub pre-outs, or one of the things that *2.ohh* suggested. Before you do that though, I'd follow his other suggestion by adjusting your gains.


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## user name unknown (Sep 2, 2001)

*Re: Line Out Converter vs. RCA Outputs on headunit (adam_pdx)*

The headunit didn't come with pre-outs on it. I had to buy the adapter seperate from Crutchfield. It plugs into the back of the Blaupunkt headunit and give me RF, LF, RR, and LR pre-outs. I am using the RR and LR to send the signal to my amp that is powering my subs.
I don't have much of an option on my headunit. I can adjust bass, treble, fader, and balance. That is it. I have something called X-BASS. That is about it though.
I knew I should have bought a better model headunit.


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## 2.ohh (Jun 21, 2002)

*Re: Line Out Converter vs. RCA Outputs on headunit (user name unknown)*

look at the x-over on the amp. if that is too high, it'll cut out the higher bass. course that's what falls into the mid-bass region, so the 8's in my front doors kick for those


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## user name unknown (Sep 2, 2001)

*Re: Line Out Converter vs. RCA Outputs on headunit (2.ohh)*

I went outside and played with the amp and I think I made an improvement. Its starting to sound better. I will play with it more tomorrow when I can actually see. It's not good to mess around with electrical equipment in the dark. Good thing we don't have a flashlight here!
Thanks for everyones help!


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