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Basic system tuning and gain settings

Fun_Bucket

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I've noticed we have a few threads which advise people on things like what to buy within a certain budget, where to buy it, and in some cases even how to install it. But we don't really have a thread that goes into detail about how to setup and tune your system once everything has been purchased and installed.

Below is a method to tuning a car audio system, and setting amplifier gains. Now it should be mentioned that this is just one way of many. This isn't meant to be a rule book on how to do it, rather a helpful starting point for someone with less knowledge and experience. It is also designed to be as safe as possible by going to extra lengths to avoid any more of those "it was working yesterday" threads.

This guide will be based upon a simple setup containing a front set of speakers, and a subwoofer. If the system in question has any additional speakers or amplifiers, then the same approach can be taken for any additional channels the system may have. This is something that you can print out and take out to your car and follow step by step. Nothing is complicated, follow the instructions, and even the most inexperienced novice can tune and set a system up to achieve something that sounds reasonable.

For examples sake the head unit in this guide has a volume level of 0 - 40. If your head unit differs from this, then simply take into account any difference. This will be a basic guide only and for that reason i will leave out more advanced things like active crossovers ,time allignment, clipping points ect. Remember, BASIC !!

I figure if someone is building a system of that level then they most likely have some level of background and experience, and would be setting the system up with more specific listening preferences.

I will try to keep things as simple as possible, and i will try to limit the use of technical terms, in which case i will do my best to explain them. Remember this is designed for someone who has no idea on where to begin.
 
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Fun_Bucket

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Settings - HPF, LPF. What are they, and what do they do?

HPF - High Pass Filter.
Is designed to cut out frequencies below a set chosen point. The main use of a HPF, is to limit the frequencies being sent to full range drivers. (basically your incar speakers, whether they be front or rear) Full range speakers can come in various different sizes wether they are 5'', 6.5'' ect, bascially anything that is not a sub woofer. The thing to remember when dealing with full range speakers, is that they are not designed for producing the entire frequency spectrum.

Most speakers will come with some form of spec sheet detailing their frequency response, amongst other things. The lower the frequency, basically the lower the note. Bass is low frequencies, high is , well, high, you get the point. Now a small speaker will not produce low frequencies very well, that is because it's not the speakers purpose, put simply they just aren't designed for it.

Now your HPF, when set, will cut out the frequencies that these smaller speakers are not capable of producing, and if they try to produce will cause the speaker to distort very early on or when the volume is increased. Depending on what equipment you are using, some will offer more adjustments than others. A good starting point for most basic systems for setting your HPF, is around 80 - 100hz. Some high quality speakers will play a bit lower than this, and would allow for the HPF to be set slightly lower.

LPF - Low pass filter
Works in the same way as a HPF, only now we are cutting out high frequencies, as aposed to cutting out the low. A LPF filter is used to cut out high frequencies that are either unwanted, or are outside the frequency response capabilties. The main use of a LPF in this guide and in most applications is for cutting out high frequencies going to a sub woofer. Just like your full range speakers, your sub woofer has a frequency range which it is designed to operate in. Obviously there is no point is sending high frequencies such as vocals, or symbals, to a subwoofer, like you wouldn't send a bass line to a tweeter, basic enough?


As a good starting point, setting your LPF, either on, or just above your HPF settings for your full range speakers , so in this case around the 80 - 100hz mark again is a good starting point. This will mean that there is no gap between in frequencies, and will allow for good integration between both your speakers and sub woofer. Your don't want to go over lapping, what you will end up with is more than one component producing the same frequency.

Now your amplifiers may have crossover adjustments rather than high and low pass filters, which will work in the same way, so depending on which one you have they are to be set accordingly.

Just remember, that everytime you disconnect the power to the head unit, you may lose settings. So after each time, go back and check you HPF and LPF settings before adjusting the amplifiers gains.
 
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Fun_Bucket

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Setting your amplifiers gains.

Now that you have set your HPF and LFP or crossovers set accordingly, you can begin to set the gains on your amplfiier/s. This is where a lot of people tend to either shy away, or have been mislead in the past and go about making incorrect adjustments.

First things first, the gain does not have anything to do with the amplifiers power output. Setting the gain higher does not make the amplifier produce any more power.

What are gain settings, and how do i adjust them?
The gain setting on an amplifier is very simple and does one thing and one thing only. It controls how loud ( note again, not how powerful) the amplifier will be when controlled from a seperate source, in this case that source is your cars head unit.

This dosen't mean however that your sound system will be louder if you go around and set all your gains to high, that isn't how it works, so keep reading before you rush out and go making any adjustments.

As mentioned, we are setting how loud the amplifier will be when we make a volume adjustment via our cars head unit. The idea is to have as much control of the adjustment as possible by being able to make any increase / decrease in volume in the smallest increments possible.

In other words if our head unit has a volume range of 0 - 40, there is no point in our sound system reaching it's full potential at a 1/4 of the available volume range.

I always advise to set the gains on one amplifier at a time, by completely disconnecting anything else. This allows you to concentrate much better on what it is your supposed to be hearing. There's nothing worse than trying to do two things at once.

Let's begin.
Other than your HPF and LPF or crossover settings that you have made on your amplifiers, anything like bass boost, or pre-set equaliser settings are to be turned off. Any other settings you have such as bass, treble ect are to be set to factory settings, whether this be 0, some units differ. Basically do not have anything other than your filters adjusted.

Begining with our speakers.
As a safety note / warning, never remove or connect any cable while the battery is still connected. Always disconnect the amplifiers power cable at the battery, not at the amplifier end, otherwise when you re-connect your battery you will have a live wire loose.

Now Disconnect your battery, and then disconnect your power cables going any other amplifiers other than that of your speakers.

Re-connect your battery, and turn your head unit on.

Now turn the amplifier gain to absolute minuimum. Next pick a volume level that is close to the maximuim number on your head unit. If your goes form 0 - 40, then somewhere around 35 is good. Remember that number, write it down or on your hand if you must. Turn your head unit to that volume level.

Begin playing some music. Very slowly, you want to increase the gain level on the amplifier. This is made easier if you have assistance from another person, saves you going backwards and forwards, and also allows you to concentrate more. Continue to increase the gain until the first sign of any distortion and then stop. I'm not talking complete distortion, the first sign of the music breaking up and that's the point to stop, or tell your assistant not to go any further.

Now to set the gain on your sub.
You want to start in the same order, by disconnecting your battery, and connecting only the amplifier that is powering the sub woofer.

Turn your head unit on, and again then gain settings to absolute minimuim.

That volume number you adjusted your amplifier to before, is the same number you want to use again. So set your head unit to that volume level.

Begin playing music again, exactly like you did before, and slowly start increasing the gain levels. Now it can be a little more difficult to hear distortion coming on through a sub woofer than it is with a set of full range speakers, so spend some more time here if need be, and use a number of different tracks with different levels and frequencies of bass.

Again once you begin hearing the first signs of distortion, stop increasing the gain levels.

Disconnect your battery and you are now free to re-connect any existing amplifier aswell. If for some reason you have a seperate amplifier for something like rear speakers, then the same process above is applied and repeated.

Your amplifiers gain settings will now be set so that you both your speakers and sub woofer will reach their full potential at the same time, at the same volume level, and with as much adjustment available in volume increase / decrease increments.

There you go that's your HPF and LPF set, and your amplifiers gains correctly adjusted.
 
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acarmody

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Who do we ask to make this sticky?

Well done HCVP, this ought to save us some time with some noobies.

Maybe we can make another thread on how to hook up some gear. H/Us, amp, speakers, etc.
 

2LOUD2OLD

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good work HCVP, thankyou for taking the time to put this together

though can I provide some comments
For the HU volume when setting gains I find that it is better to find the volume on the HU where the HU starts to clip the signal. So my method is to have all gains on min then slowly turn the HU up until you hear distortion then back it off 1 or 2 notches. this is where the HU should stay while setting gains and also is the max you should ever put the volume at. It is quite common for a HU to distort before max volume so is always good to know where that point is.

another small thing is it isnt really necessary to disconnect the power for each amp, it is far easier to just remove the RCAs, just personal preference but it certainly makes life a lot easier, especially if using a distro block for power.

finally, when setting gains for the sub, I always find it is far easier to just play tones, I will usually initially play about a 40-45Hz tone to set the gains then play some others either end ie ~60Hz and 30Hz just to ensure it is still all good. I just find it is easier to hear distortion on tones than it is on music, though unfortunately this doesnt really apply to the front speakers.
 

acarmody

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On my Kenwood H/U I have the option of turning off the in-built amplifier when only using RCAs. Would this mean it shouldn't ever distort (the H/U signal) no matter how high the volume know is?
 

2LOUD2OLD

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no it doesn't, the HU itself could clip the signal, when using RCAs you are bypassing the inbuilt amp anyway
 

SuperSixty6

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Just an idea - May want to edit your title, With something like 'How to" .

Reason #1 - Being, Allot of new members, Just seem to flick over things to quick and find the 'new thread' button to easy. This should save most new threads on the matter.

Reason #2 - I annitially thought ' Hmm that doesn't look right, HCVP looking for help ' :p
 

Fun_Bucket

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2 LOUD, trying to explain to someone how to find the point of clipping on a head unit could be a little difficult. If they don't completely understand it, then they may run into problems. While i agree with you i think someone starting out might have a hard time getting their head around it. I also figured it would be better for a beginner to just compete disconnect the power. How many times have we heard stories where things have gone wrong from people not paying attention they are plugging, or unplugging something. This way they take no chances , if they follow it, we won't get any more of those "it was working now it isn't" threads.

Super sixty - I didn't label it as a how to, because people have their own different methods, just like 2 LOUD, and some systems will differ from others. Its more of just a basic guide some one can follow if they aren't sure and can't find any other info.
 

VKCOMMO

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HC, Just a quick question..

Today i tuned in my amps, I set the volume on the HU to 42/42, And itunes to full, then started to turn up the gain, I was able to get it to full without any distortion.

Is this right????
 
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