tuning stereo

[Jessie55]

ok so im pretty good at installing car audio/video and not to shabby at making everything sound good but im lost when it comes to figuring out just how far i can push my subs what is the best way in determining how high your settings should be or how far can a sub push out before it might blow if it helps im running a 600 RMS Alpine amp to two 10 inch Rockford P2's that handle 200 RMS each.....nothing huge i just want to know how far i can go lol.

[otter]

The ideal way to tune a car stereo is to use a RTA (real-time analyzer) while playing pink noise. I've never done it this way, but I would really like to, and it is the best way that I know of.

[DangerousDan]

turn your amps down, turn your radio up until it distorts and then turn it down a little past where it starts to distort. start with the highs making them as loud and clear as possible with your amp. that is your max volume, and you should never exceed it. next, move to the subs. adjust them so that at the loudest volume allowable they are not being distorted.

all types of sources and all types of music require different adjustments, so pick something you listen to frequently. If you have a graphic equalizer it is much easier to adjust for different qualities/types of music.

also, your subs should not overpower your mids and highs. if that is the case you need to spend some more money, or turn your subs down and not utilize all the power. with evenly matched speakers and amps your highs will be crisp and clear at levels that will make your ears bleed and your subs will rattle your car apart.

you don't have to spend tons of money to get there either, just make sure you don't have 10000 watts for your three subs and 15 watts for you other four speakers What is the RMS per channel at the resistance your speakers provide? I am guessing it's 300x2@4, since rockford usually doesn't fluff numbers with 2ohm ratings. if so, and you aren't trying to use the HU or factory amp for your highs, you should be able to crank it wide open and not damage the speakers. overpower is not as bad as underpower, especially when referring to subs.

[theCybe]

You should set your gains with a multimeter, here's a writeup, and even a link to an interactive tutorial.

http://www.subwoofertools.com/forum/setgain.asp


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Here are the basic steps. It sounds to me like you're only using an external amplifier for your subwoofer;

*** You need:
-- 60Hz 0db tone (http://www.realmofexcursion.com) on CD
-- Digital Multimeter / Voltmeter

So, set all the controls on your headunit to neutral, null, off, none, negative. In other words, no bass boost, no BBE, no extra processing.

Disconnect the subwoofer from the amplifier, and turn the gain or "input sensitivity" down -- Toward 8 volts is "down," toward 0.2 volts is "up."

Turn the volume up on your headunit to the point where your interior speakers are too loud to listen to normally. This should be the point just before they start distorting and breaking up.


Set your multimeter to show ac volts.
Insert the CD with your 60hz tone, and play it.

-

Attach the leads of the DMM to the output terminals of the amp; if you're not running a monoblock amp connect the leads to the proper output terminals for 'bridged mode'. This is sometimes the two outer-most terminals, sometimes first and third terminal; It's in the manual, or marked on the amp. (You should read the manual too, btw.)

Here's what you're shooting for.

* If your subwoofer is a dual 4 ohm voicecoil woofer
* and the coils are wired in parallel to yeild 2 ohms
* and the amplifier is rated to do 600 watts into 2 ohms (by 1 channel)

You need to figure

sqrt(2*600)=34.64.

On the amplifier, adjust the gain until your multimeter reflects a number close to that figure. 32.5 will be fine.

Before you run with these numbers, make sure you have the proper rating for your amplifier in watts RMS ('root mean square')





um.. yep, so you can reconnect your subwoofer now. Don't forget to turn the volume back down before you put some music in






.. Sorry for the dirty writeup, it's 2:30am.

[DangerousDan]

what's the purpose of setting your gain with a DMM, and how does this take into account his six other speakers?

[theCybe]

The purpose of setting your gain with a DMM is to avoid clipping. He should tune his other channels the same way, but he's running them off the headunit which makes it a pain in the ass. They'll probably survive some clipping, but a big amp in clipping on a little sub is much more likely to be an issue.

[DangerousDan]

I don't think he has enough power for him to get anywhere near that point without distorting the speakers audibly, for either the speakers or amp at any resistance or configuration. also, since he is using the factory HU and tunes it the way you are suggesting the subs will overpower the highs at even a medium setting on the volume.

If you are tuning a competition system then you need complex electrical and acoustical measuring devices, if you are adding a couple subs and a small amp to your factory HU you need to adjust the lows to coincide with the highs. you will not be able to hear your mids or highs at all when you have the subs turned wide open on the amp. no way man, not on a factory HU, not even for 2 10's. if that's what you want then tune it out like he suggests, if you want to be able to hear it don't worry about blowing this setup, it won't happen.

[theCybe]

I beg to differ - most people are dissatisfied with the lack of volume from their substage when they set the gains properly (using a multimeter.)

That's why the first step is to turn the headunit up to a level that's louder than you'd normally listen to -- then the amplifier is getting a stronger input signal than it will normally see under regular use.

Gain affects the amplitude of the signal, not the volume of the music. A user is free to adjust his volume as he sees fit - the idea is that even at a level that's not comfortable to listen to up front, the sub-stage won't be overdriven.

We could probably go around for hours on this one, but I guess there's room for opinions even in science.

Set it correctly - science says set it by number, using the multimeter. You don't tune your evo by the seat of your pants, you use calibrated software!

(IMO? I guess.)

If you want it louder, build a different enclosure, buy a larger amp, or make adjustments elsewhere. But /don't/ crank the gains up.

it won't blow

famous last words.

[DangerousDan]

rockford says that both the p2d410 and p2d210 are 250RMS.

http://www.rockfordfosgate.com/produ...n_US&p_status=

what is the RMS per channel for your amp? if it is 300x2@4 ohms and you got the dual 4 ohm VC's you should bridge it to 600x1@4ohm. that will get you to 300 each speaker and not run the amp real hot. if you don't get the wiring let me know. since your speakers are so well matched to your amp you want to stay with the 4 ohm rating. it will keep things cooler and your electrical system won't strain as much. if you got the dual 2 ohm VC's then go with the 300x2@4 setup.

[theCybe]

Originally Posted by DangerousDan

rockford says that both the p2d410 and p2d210 are 250RMS.

http://www.rockfordfosgate.com/produ...n_US&p_status=

what is the RMS per channel for your amp? if it is 300x2@4 ohms and you got the dual 4 ohm VC's you should bridge it to 600x1@4ohm. that will get you to 300 each speaker and not run the amp real hot. if you don't get the wiring let me know. since your speakers are so well matched to your amp you want to stay with the 4 ohm rating. it will keep things cooler and your electrical system won't strain as much. if you got the dual 2 ohm VC's then go with the 300x2@4 setup.

Dual 4 ohm VC = 2 ohms per driver;

Internally bridged would make it 1 ohm to the amp.

I don't mean to be rude, but your sig talks about misinformation - I don't want to see this guy poof his amp or subs.

[DangerousDan]

Originally Posted by theCybe

I beg to differ - most people are dissatisfied with the lack of volume from their substage when they set the gains properly (using a multimeter.)

That's why the first step is to turn the headunit up to a level that's louder than you'd normally listen to -- then the amplifier is getting a stronger input signal than it will normally see under regular use.

Gain affects the amplitude of the signal, not the volume of the music. A user is free to adjust his volume as he sees fit - the idea is that even at a level that's not comfortable to listen to up front, the sub-stage won't be overdriven.

We could probably go around for hours on this one, but I guess there's room for opinions even in science.

Set it correctly - science says set it by number, using the multimeter. You don't tune your evo by the seat of your pants, you use calibrated software!

(IMO? I guess.)

If you want it louder, build a different enclosure, buy a larger amp, or make adjustments elsewhere. But /don't/ crank the gains up.



famous last words.

I do see your point, but I don't see how it applys in a factory HU system. I am saying when you turn the knob all the way up there will not be enough volume for you to hear the factory equipment over the subs when you set the gain properly. your method is sound, and completely accurate, but he can only adjust one amps gain and has no way to increase the output of the factory system to match the new subs.

basically what I am saying is that unless he is going for all boom (and in that case he bought the wrong equipment) adjusting it that way will create an imbalance in volume between lows and highs. he will not be able to utilize all the power available with this setup without at least adding a 4 channel amp, possibly not without replacing components.

[DangerousDan]

and I hope he is using a sealed box. I can't stand the bandpass box. yeah, it's loud, but that's all. I want an actual reproduction of the music, and I listen to more than just rap so one frequency isn't going to cut it. If you want more base buy a 15 you only need one

[DangerousDan]

Originally Posted by theCybe

Dual 4 ohm VC = 2 ohms per driver;

Internally bridged would make it 1 ohm to the amp.

I don't mean to be rude, but your sig talks about misinformation - I don't want to see this guy poof his amp or subs.

you can wire a dual 4 ohm to 8 ohms, then you wire your 8 ohms in parallel to the amp for 600x1@4. how's that wrong?

alternately, dual 2 ohms wired seperately to the amp at 300x2@4.

seems pretty clear to me

EDIT: you do realize he has two speakers right?

[theCybe]

I see what you're getting at. I think most new audio users have the urge to be loud, and will wire in parallel.

im lost when it comes to figuring out just how far i can push my subs what is the best way in determining how high your settings should be or how far can a sub push out before it might blow

My guide was more in the vein of getting the most sound out of those woofers safely. Everyone's hearing has it's own personality as far as peaks and dips in perceived response. Blending your stages to your own personal preference and hearing response is something that you have to do by ear, I agree.

So look at my post as a way to establish a maximum safe output, and tune down from there if needed.

I just removed about three kilowatts worth of substage from my tC; and I've found happiness in quality with a simple set of 6.5" components, 200 watts, some time alignment, and a little eq tweaking.

Whichever way he goes, I think he got some good info from us both. When the SPL bug bites, it bites pretty hard.

[DangerousDan]

I agree

I have a 10 and a 12, and only recently lost the ability to adjust each independantly for the music type(eq **** the bed) I'm all about the output quality, and max volume is way out of my league at this point in my life. I find it annoying to run at very loud levels for more than a good song or two, and only when I am specifically in the mood. what happened to my three 12 1000 watt teen years