I was just wondering. How much or what differnce does the volt rating of a HU make? I know the higher the volt that comes out of the HU, the louder the music plays. But I will like to get a professional response out of this. I.E. If I had an ideal system, lets say one 5-channel amp with all aftermarket speakers and sub. Will the system sound louder if I had an HU with 5v rating, or one with an 8v rating? I'm assuming that the quality build of the HU overall will make the difference at the end. Because with personnal experience, I had an Eclipse HU, that was made in 99 or maybe 98 lol, but the volt rating was 5, thats why I picked it up, but later installed an sony HU, that would allow me to play my ipod, but only had a rating of 2v, and it was made in ~05 and it sounded louder with all the other equipment not changed.

Thanks

It is completely unrelated to output as long as you have a half way decent amp. It is functionally the reason there is a gain knob on the amplifier.

As M5 said, the entire reason amplifiers have a gain knob is to allow the amplifier to provide full power output with a wide range of input voltages. If you properly readjust the gain, there would be zero difference in output levels between a 2V headunit and an 8V headunit.

What happens most of the time is that someone switches from a lower preamp voltage headunit to a headunit with a higher preamp voltage output, and then don't readjust the gain on the amplifier to compensate for the increase in input voltage the amplifier receives. In those cases the output increases because of the higher preamp voltage, but only because the installer did it wrong and didn't properly readjust the amplifier's gain setting.

So your saying that the output voltage a HU puts out has NOTHING to do with the output of the speakers? So then what is the purpose of an line driver? I'm confused, so by the installer wrongly adjusting his gains after installing a higher rated HU, the output is louder until he readjusts his gains?

Supposedly higher voltage = better signal and better SQ. However, some of the best SQ HU's have low pre out voltage, so take it with a grain of salt.

It would be louder because the signal is most likely being clipped since the gains between the HU and Amp do not match.

Supposedly higher voltage = better signal and better SQ. However, some of the best SQ HU's have low pre out voltage, so take it with a grain of salt.

It would be louder because the signal is most likely being clipped since the gains between the HU and Amp do not match.

:ughdunno:hmmmmm, alright

Higher voltage HU's allow amplifier gain settings to be adjusted lower which will allow more amplifier headroom.

If you have a strong input signal you can set your gain lower than if your input signal was weak. A lower gain setting allows for more dynamic headroom. What this means is that the amplifier can produce a cleaner output signal without clipping. Music has peaks and dips some peaks can be +3db stronger than others (0db signal). That 3db signal requires the amplifier to work much harder than baseline; often this is where clipping occurs.

Just my very brief comment on a complicated subject.

Higher voltage HU's allow amplifier gain settings to be adjusted lower which will allow more amplifier headroom.

If you have a strong input signal you can set your gain lower than if your input signal was weak. A lower gain setting allows for more dynamic headroom. What this means is that the amplifier can produce a cleaner output signal without clipping. Music has peaks and dips some peaks can be +3db stronger than others (0db signal). That 3db signal requires the amplifier to work much harder than baseline; often this is where clipping occurs.

Just my very brief comment on a complicated subject.

Hey thanks for explaining that to me. I understand much better, it makes sense too. Where can I find more detailed infromation about this, do you know? I understand what your saying, I would just like to read up on it, to burn time @ work, and learn a little bit lol.

Higher voltage HU's allow amplifier gain settings to be adjusted lower which will allow more amplifier headroom.

If you have a strong input signal you can set your gain lower than if your input signal was weak. A lower gain setting allows for more dynamic headroom. What this means is that the amplifier can produce a cleaner output signal without clipping. Music has peaks and dips some peaks can be +3db stronger than others (0db signal). That 3db signal requires the amplifier to work much harder than baseline; often this is where clipping occurs.

Just my very brief comment on a complicated subject.

Hey thanks for explaining that to me. I understand much better, it makes sense too. Where can I find more detailed infromation about this, do you know? I understand what your saying, I would just like to read up on it, to burn time @ work, and learn a little bit lol.

Check out David Navone and Richard Clarks's tech pages. Most of them are viewable online, I can't remember where. Maybe carsound or speakerworks.

Also alot of info by doing a Google search.

Edited December 17, 201014 yr by edouble101

Higher voltage HU's allow amplifier gain settings to be adjusted lower which will allow more amplifier headroom.

If you have a strong input signal you can set your gain lower than if your input signal was weak. A lower gain setting allows for more dynamic headroom. What this means is that the amplifier can produce a cleaner output signal without clipping. Music has peaks and dips some peaks can be +3db stronger than others (0db signal). That 3db signal requires the amplifier to work much harder than baseline; often this is where clipping occurs.

Just my very brief comment on a complicated subject.

I'm not sure sure about that a lower gain setting provides more headroom. Simply because the gain knob is just for level matching.

But if you can provide a link to the article I'll happily read it

Higher voltage HU's allow amplifier gain settings to be adjusted lower which will allow more amplifier headroom.

If you have a strong input signal you can set your gain lower than if your input signal was weak. A lower gain setting allows for more dynamic headroom. What this means is that the amplifier can produce a cleaner output signal without clipping. Music has peaks and dips some peaks can be +3db stronger than others (0db signal). That 3db signal requires the amplifier to work much harder than baseline; often this is where clipping occurs.

Just my very brief comment on a complicated subject.

Hey thanks for explaining that to me. I understand much better, it makes sense too. Where can I find more detailed infromation about this, do you know? I understand what your saying, I would just like to read up on it, to burn time @ work, and learn a little bit lol.

Check out David Navone and Richard Clarks's tech pages. Most of them are viewable online, I can't remember where. Maybe carsound or speakerworks.

Also alot of info by doing a Google search.

Bueno :-)

Higher voltage HU's allow amplifier gain settings to be adjusted lower which will allow more amplifier headroom.

If you have a strong input signal you can set your gain lower than if your input signal was weak. A lower gain setting allows for more dynamic headroom. What this means is that the amplifier can produce a cleaner output signal without clipping. Music has peaks and dips some peaks can be +3db stronger than others (0db signal). That 3db signal requires the amplifier to work much harder than baseline; often this is where clipping occurs.

Just my very brief comment on a complicated subject.

I'm not sure sure about that a lower gain setting provides more headroom. Simply because the gain knob is just for level matching.

But if you can provide a link to the article I'll happily read it

I thought it lowered the noise floor....

Higher voltage HU's allow amplifier gain settings to be adjusted lower which will allow more amplifier headroom.

If you have a strong input signal you can set your gain lower than if your input signal was weak. A lower gain setting allows for more dynamic headroom. What this means is that the amplifier can produce a cleaner output signal without clipping. Music has peaks and dips some peaks can be +3db stronger than others (0db signal). That 3db signal requires the amplifier to work much harder than baseline; often this is where clipping occurs.

Just my very brief comment on a complicated subject.

I'm not sure sure about that a lower gain setting provides more headroom. Simply because the gain knob is just for level matching.

But if you can provide a link to the article I'll happily read it

Nope :-( couldn't find anything...

Higher voltage HU's allow amplifier gain settings to be adjusted lower which will allow more amplifier headroom.

If you have a strong input signal you can set your gain lower than if your input signal was weak. A lower gain setting allows for more dynamic headroom. What this means is that the amplifier can produce a cleaner output signal without clipping. Music has peaks and dips some peaks can be +3db stronger than others (0db signal). That 3db signal requires the amplifier to work much harder than baseline; often this is where clipping occurs.

Just my very brief comment on a complicated subject.

I'm not sure sure about that a lower gain setting provides more headroom. Simply because the gain knob is just for level matching.

But if you can provide a link to the article I'll happily read it

Proper setting will give you more amplifier headroom than if you had the gain setting mismatched. This doesnt make the amplifier make for power.

You guys really need to rely on the internets for simple searches for information such as this. Research the topic from numerous reputable sources. Remember what may work for somebody else may not work for your equipment in your vehicle. <---- This is one reason you have to gather your information for multiple resources. Then come to your own conclusion. You can then apply your newly found knowledge to your situation and needs. What I say may not be true (I am only a machinist not an installer) that is why you need to research it and come up with your own opinion.... geez lol

This was a quick search <5 minutes

Level Setting by Richard Clark

RaneNote - Setting Sound System Level Controls

Amplifier Gain Controls by Eddie Runner

SSA!!! Amplifier gains and preouts

Head Unit Features carstereo.com - Read about RCA outputs

Not all of it may apply to this topic but there are tid bits within the links that do.

I have a beer exchange to go to now. I dont know what it is but it is all about beer

Edited December 17, 201014 yr by edouble101

Proper setting will give you more amplifier headroom than if you had the gain setting mismatched. This doesnt make the amplifier make for power.

If there is no more power then there is no additional headroom. Headroom is power available beyond what is needed for normal sound production. If the amp is capable of producing 200W and the normal power used on music is 50W you have 6dB of headroom in the system. Gain setting is not related to headroom. Gain setting is not related to how "hard" the amp works. Setting it correctly allows you to get full power from the amp regardless of source voltage. Having it set incorrectly does one of two things. If it is set too high, you have a very limited range of usable source volume control before the amp is driven into clipping. If it is set too low, you simply will never get full power from the amp. It is really that simple.

The only benefit that you might see from higher signal voltage is the reduction in gain can keep noise out of the system. Every signal cable has a noise level present in it. The voltage of that noise stays constant. With an extremely low signal voltage, the gain on the amp has to be turned up and that amplifies not only the signal, but also the noise. Higher signal voltage essentially increases the s/n ratio of the signal cabling. 2V is way more than enough to completely overcome the line noise in most any system. Beyond that its all about marketing.

I have a beer exchange to go to now. I dont know what it is but it is all about beer

Sounds like my kind of gig.

So your saying that the output voltage a HU puts out has NOTHING to do with the output of the speakers?

Nope.

So then what is the purpose of an line driver?

Mainly to allow the manufacturer to get more money out of your wallet and into theirs.

Some of them also include other "useful" features, such as some equalizer bands and such, which in certain circumstances may be of benefit to the system (note that it's the other features and not the "line driver" feature that would be the primary benefit to the system in this case).

But other than that the only, ONLY, benefit to a higher preamp voltage is if you are experiencing noise in your system that can only be eliminated with either a lower gain setting or higher signal voltage level, and this is rarely the case. As helotaxi said, a higher preamp voltage improves the SNR of the signal transfer and allows for a lower gain setting. Some amplifiers can have audible noise with a high gain setting, so increasing the preamp voltage allows the user to lower the gain and eliminate the noise issue. But with modern amplifier designs, this is pretty much a non-issue in most situations. Or if there is a high noise floor during the signal transfer, increasing the voltage of the signal increases the SNR of the signal. But again, this is rarely the case and in most cases routing signal cables away from noisy areas in the vehicle will solve the issue.

I'm confused, so by the installer wrongly adjusting his gains after installing a higher rated HU, the output is louder until he readjusts his gains?

The gain (or input sensitivity) knob is on the amplifier to allow the amplifier to output full power with a wide range of input voltages. The gain knob basically adjusts the level of the input signal so that it will effectively "see" the same amount of input voltage. Rather you start at 2V or start at 8V, if you properly set the gain the amplifier won't know the difference and it will output the same amount of power in either circumstance. If you properly set the gain, there would be no difference in output levels between a 2V headunit and an 8V headunit.

Now, what happens if you start with a 2V HU and then switch to an 8V HU but don't readjust the gain? The amplifier is set to adjust the input signal based on an expected 2V of input signal. But you are now sending it 8V, so it's not properly adjusting the level of the input signal. It's receiving a lot more than it was expecting to see. As a result, it's going to output more power because it's letting too much of the input signal pass through to the amplification stage. This means the amplifier is going to output more power with the gain set to the 2V setting and an 8V input signal than it would with a 2V setting and 2V of input signal. In order for the amplifier to properly adjust the input signal for the higher 8V input signal, the gain would need to be reset to the 8V setting.

Now you might be thinking "Hey, cool, if I don't readjust the gain that means I can get a lot more power out of my amplifier then, right?" No, this is bad. This is bad because the amplifier is going to amplify the input signal too much and clip the signal it is outputting to your speakers or subwoofers. This clipped signal contains more average power than the amplifier operating below clipping (with a properly set gain), and as a result could potentially damage your speakers or subwoofers depending on the circumstance.

Proper setting will give you more amplifier headroom than if you had the gain setting mismatched. This doesnt make the amplifier make for power.

If there is no more power then there is no additional headroom. Headroom is power available beyond what is needed for normal sound production. If the amp is capable of producing 200W and the normal power used on music is 50W you have 6dB of headroom in the system. Gain setting is not related to headroom. Gain setting is not related to how "hard" the amp works. Setting it correctly allows you to get full power from the amp regardless of source voltage. Having it set incorrectly does one of two things. If it is set too high, you have a very limited range of usable source volume control before the amp is driven into clipping. If it is set too low, you simply will never get full power from the amp. It is really that simple.

Just to reinforce this......amplifier gain setting has nothing to do with headroom.

Thanks for your knowledgable input Impious. Maybe you could help me with my install, seriously. Excpect a PM

There is one "other" use for a line driver. If you have 10 amps all connected to one output and the output voltage drive isn't enough to reach a point on the input stage of the amplifier to actually allow it to reach reach power. Otherwise in any modern amp as stated above there is no benefit and IMO anything extra in the signal path that isn't there for a reason is a terrible thing. KISS.

Higher voltage HU's allow amplifier gain settings to be adjusted lower which will allow more amplifier headroom.

If you have a strong input signal you can set your gain lower than if your input signal was weak. A lower gain setting allows for more dynamic headroom. What this means is that the amplifier can produce a cleaner output signal without clipping. Music has peaks and dips some peaks can be +3db stronger than others (0db signal). That 3db signal requires the amplifier to work much harder than baseline; often this is where clipping occurs.

Just my very brief comment on a complicated subject.

I'm not sure sure about that a lower gain setting provides more headroom. Simply because the gain knob is just for level matching.

But if you can provide a link to the article I'll happily read it

Proper setting will give you more amplifier headroom than if you had the gain setting mismatched. This doesnt make the amplifier make for power.

Which is exactly why I asked about the article...Had I found that, I wouldn't have interpreted it by "low gain setting = headroom".

Anyway...just for fun...we used an Ipod as source for a 4 channel + sub amp, so at most 1V of clean output. Needless to say, it was easy getting the amps into clipping.

So your saying that the output voltage a HU puts out has NOTHING to do with the output of the speakers?

Nope.

So then what is the purpose of an line driver?

Mainly to allow the manufacturer to get more money out of your wallet and into theirs.

Some of them also include other "useful" features, such as some equalizer bands and such, which in certain circumstances may be of benefit to the system (note that it's the other features and not the "line driver" feature that would be the primary benefit to the system in this case).

But other than that the only, ONLY, benefit to a higher preamp voltage is if you are experiencing noise in your system that can only be eliminated with either a lower gain setting or higher signal voltage level, and this is rarely the case. As helotaxi said, a higher preamp voltage improves the SNR of the signal transfer and allows for a lower gain setting. Some amplifiers can have audible noise with a high gain setting, so increasing the preamp voltage allows the user to lower the gain and eliminate the noise issue. But with modern amplifier designs, this is pretty much a non-issue in most situations. Or if there is a high noise floor during the signal transfer, increasing the voltage of the signal increases the SNR of the signal. But again, this is rarely the case and in most cases routing signal cables away from noisy areas in the vehicle will solve the issue.

I'm confused, so by the installer wrongly adjusting his gains after installing a higher rated HU, the output is louder until he readjusts his gains?

The gain (or input sensitivity) knob is on the amplifier to allow the amplifier to output full power with a wide range of input voltages. The gain knob basically adjusts the level of the input signal so that it will effectively "see" the same amount of input voltage. Rather you start at 2V or start at 8V, if you properly set the gain the amplifier won't know the difference and it will output the same amount of power in either circumstance. If you properly set the gain, there would be no difference in output levels between a 2V headunit and an 8V headunit.

Now, what happens if you start with a 2V HU and then switch to an 8V HU but don't readjust the gain? The amplifier is set to adjust the input signal based on an expected 2V of input signal. But you are now sending it 8V, so it's not properly adjusting the level of the input signal. It's receiving a lot more than it was expecting to see. As a result, it's going to output more power because it's letting too much of the input signal pass through to the amplification stage. This means the amplifier is going to output more power with the gain set to the 2V setting and an 8V input signal than it would with a 2V setting and 2V of input signal. In order for the amplifier to properly adjust the input signal for the higher 8V input signal, the gain would need to be reset to the 8V setting.

Now you might be thinking "Hey, cool, if I don't readjust the gain that means I can get a lot more power out of my amplifier then, right?" No, this is bad. This is bad because the amplifier is going to amplify the input signal too much and clip the signal it is outputting to your speakers or subwoofers. This clipped signal contains more average power than the amplifier operating below clipping (with a properly set gain), and as a result could potentially damage your speakers or subwoofers depending on the circumstance.

Hey thanks a lot for replying and explaining this to me bro. I really do appreciate it. You took a lot of time to fill me in on this, just wna say thanks. It all makes sense, and it answer my question.

You're welcome

Car audio is a business.

Lots of marketing tricks, and the high voltage on some h u is a trick to fool customers !

You must not make your h u choice on output voltage.

thanks for all these infos, guys !

Car audio is a business.

Lots of marketing tricks, and the high voltage on some h u is a trick to fool customers !

You must not make your h u choice on output voltage.

thanks for all these infos, guys !