Tuning (long)
10-06-2004, 08:44 PM
#1
Guest
Posts: n/a
Okay I am going to give you guys some insight into how I tune a car. This could be for competition or a dialy driver, but it will definately not have anything to do with SPL tuning. I may have to break it up into a few parts and if you guys have any ideas I can add them to the original post. Without further ado.
1. Install, it's the first step in tuning. Make sure your speakers are mounted where they sound best and are solidly mounted to a non resonant baffle. Make sure their is no noise in the system, it ruins any system and should be done before actual tuning.
2. Get your reference. Live music is great. But unless you have an acoustic jazz trio playing the same music as your tuning with it'ss not practical, you will need to listen to your reference then go directly to the car. For this I recomend headphones, I use a $80 pair of Sennheiser's. Head phones are definately the way to go as you don't have to spend a fortune for good sound and they take the effects of the listening area out of the equation.
3 Set your crossovers. To find the optimal crossover frequencies I recomend calling the manufacturer, they should be able to provide you with accurate starting points. I prefer this to going by specs or spec sheets as you can discuss your install and goals, which may differ from the listed specs. Once you have them set you can move to the most important in my opinion of tuning a system, setting gains.
4 Setting Gains, this part is really easy yet seems to be the most overlooked part of many installs. First set all Loudness circuits, tone controls, DSP's etc. to how you will listen most of the time. Some people set these at flat but then hit loudness and screw up the gain settings. If you set the gains with these controls set to where they will usually be you minimize clipping and the possibility of system damage. Now you need a test CD with al high bits recording, I recomend Autosound2000 CD104, I use the -10db track for customers and the -5db track for myself. You can use the 0db track but will be volume limited unless you have alot of power. I start with the 1,000 hz track and work on the midrange signal path first. Turn the volume on the deck all the way down, as well as all the gain controls in the system all the way down, play the track and turn up the volume on the deck till you hear clipping, trust me YOU WILL KNOW WHEN IT CLIPS, it clearly changes tones. Leave the deck at the volume just before you hear the distortion. Give your ears a rest if you want a 1000hz tone can be quite annoying. Next turn up the gain on the next product in the signal path till you hear the distortion, turn it down till the bad noises go away. Keep doing this until you are at the amp. If you only have one amp running the mids and tweets you can move on, otherwise you have to set the tweeter amp. You have to be careful here and give them plenty of breaks so they can recover and you don't blow them. For the sub amps I use the musical track and get the sub amp in the ball park. Clipping is not that bad on subs and the chances that it will clip very hard are very slim if you set it to blend smoothly with the rest of the system. If you have an RTA, right now you could use it to check the polarity of the speakers in relation to each other. Look for dips at the crossover frequencies, and try reversing the polarity of a pair of drivers and see if the dip is gone. Now, whether you have an RTA or not put on some music that has alot of midbass content and listen to the systems transition form midbass to subbass, now flip the subs polarity and listen to the same track, did it sound better reversed? Then leave it that way. If it didn't sound better switch it back to normal. Some decks with subwoofer outputs have a polarity selector built into the deck. Whew, gains are done and your system should be sounding much better already if you have never set gains before.
5. It's time to set the eq's. This could take up a whole book so for now I am going to give some tips and save the rest for later.
A) If you have access to an RTA look for peaks and reduce them, before trying to bring up dips. Some dips you will not be able to get rid of with an eq, only changing speaker positioning or changing interior shapes will get rid of.
B) If you don't have access to an RTA your life is really alot harder, my best advice is to find someone who has tuned many competition cars and see if they will let you sit in wjile they tune your car, buy them alot of beer if you have to. Attend a major show and their will be a tweak and tune, see if a manufacturer you use will help out.
C) One of the best ways to learn what an eq does is to play "The blind EQ game". To do this you have to have 2 eq's that are identical. Hook them up inline in the same system so you can set them both in a comfortable spot, with one person controlling each one. Make sure that the guy wanting to learn to tune is using the second eq and cannot see the first. Now have the guy with eq1 make a change, and see if they guy with eq2 can do the inverse with his. For example guy with eq1 adds 3 db at 1500 hz, see how long it takes for the guy with eq2 to subtract 3db from 1500hz. At first you can limit it to one change at 2-3 frequencies, say 500hz,1500hz, and 3000hz. As you get better you can add more frequencies and more changes.
Well that's it for now. I will add more later and maybe sticky the topic if you guys want.
1. Install, it's the first step in tuning. Make sure your speakers are mounted where they sound best and are solidly mounted to a non resonant baffle. Make sure their is no noise in the system, it ruins any system and should be done before actual tuning.
2. Get your reference. Live music is great. But unless you have an acoustic jazz trio playing the same music as your tuning with it'ss not practical, you will need to listen to your reference then go directly to the car. For this I recomend headphones, I use a $80 pair of Sennheiser's. Head phones are definately the way to go as you don't have to spend a fortune for good sound and they take the effects of the listening area out of the equation.
3 Set your crossovers. To find the optimal crossover frequencies I recomend calling the manufacturer, they should be able to provide you with accurate starting points. I prefer this to going by specs or spec sheets as you can discuss your install and goals, which may differ from the listed specs. Once you have them set you can move to the most important in my opinion of tuning a system, setting gains.
4 Setting Gains, this part is really easy yet seems to be the most overlooked part of many installs. First set all Loudness circuits, tone controls, DSP's etc. to how you will listen most of the time. Some people set these at flat but then hit loudness and screw up the gain settings. If you set the gains with these controls set to where they will usually be you minimize clipping and the possibility of system damage. Now you need a test CD with al high bits recording, I recomend Autosound2000 CD104, I use the -10db track for customers and the -5db track for myself. You can use the 0db track but will be volume limited unless you have alot of power. I start with the 1,000 hz track and work on the midrange signal path first. Turn the volume on the deck all the way down, as well as all the gain controls in the system all the way down, play the track and turn up the volume on the deck till you hear clipping, trust me YOU WILL KNOW WHEN IT CLIPS, it clearly changes tones. Leave the deck at the volume just before you hear the distortion. Give your ears a rest if you want a 1000hz tone can be quite annoying. Next turn up the gain on the next product in the signal path till you hear the distortion, turn it down till the bad noises go away. Keep doing this until you are at the amp. If you only have one amp running the mids and tweets you can move on, otherwise you have to set the tweeter amp. You have to be careful here and give them plenty of breaks so they can recover and you don't blow them. For the sub amps I use the musical track and get the sub amp in the ball park. Clipping is not that bad on subs and the chances that it will clip very hard are very slim if you set it to blend smoothly with the rest of the system. If you have an RTA, right now you could use it to check the polarity of the speakers in relation to each other. Look for dips at the crossover frequencies, and try reversing the polarity of a pair of drivers and see if the dip is gone. Now, whether you have an RTA or not put on some music that has alot of midbass content and listen to the systems transition form midbass to subbass, now flip the subs polarity and listen to the same track, did it sound better reversed? Then leave it that way. If it didn't sound better switch it back to normal. Some decks with subwoofer outputs have a polarity selector built into the deck. Whew, gains are done and your system should be sounding much better already if you have never set gains before.
5. It's time to set the eq's. This could take up a whole book so for now I am going to give some tips and save the rest for later.
A) If you have access to an RTA look for peaks and reduce them, before trying to bring up dips. Some dips you will not be able to get rid of with an eq, only changing speaker positioning or changing interior shapes will get rid of.
B) If you don't have access to an RTA your life is really alot harder, my best advice is to find someone who has tuned many competition cars and see if they will let you sit in wjile they tune your car, buy them alot of beer if you have to. Attend a major show and their will be a tweak and tune, see if a manufacturer you use will help out.
C) One of the best ways to learn what an eq does is to play "The blind EQ game". To do this you have to have 2 eq's that are identical. Hook them up inline in the same system so you can set them both in a comfortable spot, with one person controlling each one. Make sure that the guy wanting to learn to tune is using the second eq and cannot see the first. Now have the guy with eq1 make a change, and see if they guy with eq2 can do the inverse with his. For example guy with eq1 adds 3 db at 1500 hz, see how long it takes for the guy with eq2 to subtract 3db from 1500hz. At first you can limit it to one change at 2-3 frequencies, say 500hz,1500hz, and 3000hz. As you get better you can add more frequencies and more changes.
Well that's it for now. I will add more later and maybe sticky the topic if you guys want.
10-07-2004, 07:49 AM
#4
Guest
Posts: n/a
the headphone recommendation is great, very critical to understand the tonality of the tracks you will be tuning your car with but are difficult, imo, to get a grasp on stage placement, escpecially in recording that the musicians move around the stage, and a home audio reference system is a better idea, if you can find a good one. great, easy to read guide to getting started tuning a car, well done, dwvw. its amazing how slight increases and decraeses with a good eq can dramatically change the dynamics of a systems, you will usually find that after some eq adjusments you may want to re analyze your x-over points, particularily if you use full active or digital, passives make this more difficult, thats why they only deserve to be in the home [img]tongue.gif[/img] 
10-07-2004, 08:39 AM
#5
1000 Watt CAFz'r
Join Date: Oct 2003
Posts: 1,783
Great write up Dereck!!
I've got a T/A related one in the works. It should compliment what you've already posted quite well, as my 3 approaches to tuning T/A are completely indeppendant of tuning X.O./Levels/EQ.
I agree, should be a sticky.
Adam
I've got a T/A related one in the works. It should compliment what you've already posted quite well, as my 3 approaches to tuning T/A are completely indeppendant of tuning X.O./Levels/EQ.
I agree, should be a sticky.
Adam
10-07-2004, 12:54 PM
#6
Join Date: Apr 2000
Posts: 1,220
Originally posted by DWVW:
4 Setting Gains, Now you need a test CD with al high bits recording, I recomend Autosound2000 CD104, .
4 Setting Gains, Now you need a test CD with al high bits recording, I recomend Autosound2000 CD104, .
You forgot a important step though. If its a system that has seperate mids/midbass and tweets.. you need to balance the system after setting the amps gains (to max unclipped output). When doing this make sure to turn down the louder amp to balance with the others, instead of turning the quietest one up.
With my current system being fully active (4way) i spent a ton of time level matching components, and playing with phase. I have a total of 12 gains to set [img]redface.gif[/img] . I think i did a pretty good job [img]smile.gif[/img] .
[ October 07, 2004, 01:59 PM: Message edited by: chev2 ]
