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Unread 10-20-2010, 07:27 AM   #1
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Default System Configuration

Here's my setup, I already have the head unit, dash speakers, subwoofer, amplifier installed and working. I bought a pair of component speakers that have tweeters with them. I was wondering how I would connect the tweeters up to my current system, either amp or headunit? I have another 400 Watt Kicker Amp should I use that to power my other speakers?
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Unread 10-20-2010, 09:31 AM   #2
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what components did you buy? typically there is an external crossover that splits the highs and lows between the speaker and tweeter.
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Unread 10-20-2010, 12:55 PM   #3
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If you bought a pair of components that came with tweeters they usually have a resistor built in to limit power.
Do you have a crossover? if so, hooking them up to the HU would be fine if you eliminate the lower hz Anything under 500 should be eliminated when installing them. You could connect the components up to an amplifier or to your HU.

If your amplifier has 4\6channels then this would be fine however it most likely doesn't so for the time being hooking them up to your HU until you get another dedicated component amp would be sufficient.

Remember not to turn the gain up past 1\3rd and keep the hz range on the amplifier in line with what your woofer can handle.

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Unread 10-20-2010, 03:23 PM   #4
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Rockford Fosgate Prime R152-S 5.25" Component Speaker
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Unread 10-20-2010, 11:13 PM   #5
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you see how theres 4 prongs off the rear. that speaker has a built in crossover. Just hook the tweeters inline with the speakers and you'll be fine.
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Unread 10-22-2010, 09:49 AM   #6
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Quote:
Originally Posted by tofunater View Post
you see how theres 4 prongs off the rear. that speaker has a built in crossover. Just hook the tweeters inline with the speakers and you'll be fine.
Looking at it based on the web pictures, I get the impression that the woofer is just run full-range and the tweeters (hopefully) have a simple high-pass filter in them. Not the best way to do it from a sonic standpoint, but, it should keep everything alive.

If you are really looking to transition well between the woofer and the tweeter, I can explain how to get a rough measurement of the response of each and design a simple crossover to put in front of both (and while you're at it roll off the woofers so that they transition to your sub(s) smoothly). It'll take you a couple hours, but, shouldn't cost more than $20 in parts.
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Unread 10-22-2010, 10:41 AM   #7
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i never said it was an elegant design
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Unread 10-22-2010, 11:18 AM   #8
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Quote:
Originally Posted by Chipp View Post
Looking at it based on the web pictures, I get the impression that the woofer is just run full-range and the tweeters (hopefully) have a simple high-pass filter in them. Not the best way to do it from a sonic standpoint, but, it should keep everything alive.

If you are really looking to transition well between the woofer and the tweeter, I can explain how to get a rough measurement of the response of each and design a simple crossover to put in front of both (and while you're at it roll off the woofers so that they transition to your sub(s) smoothly). It'll take you a couple hours, but, shouldn't cost more than $20 in parts.
please post more info I would like to know
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Unread 10-22-2010, 08:42 PM   #9
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You should definitely use the other amp to power the speakers. And you can build a crossover (if you don't have one) relatively easily. Information can be found at the12volt.com on crossover building. But you basically use a coil for low pass, and a capacitor for high pass.

As far as setting the gain, there is a proper way to do it using a multimeter. I'll have to write up a guide on how to do it one of these days, and post it here.
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Unread 10-22-2010, 09:11 PM   #10
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Okay, fair enough. The gist of the project is using the basic properties of simple electric components to manipulate an AC signal (our AC signal here happens to be audio). A “good enough” rough guestimate of a speaker’s normal operating range can be made with a little investigative work (I/E, examining what few electrical components are present and assessing how they are effecting the signal) and using commonly available frequency-sweep software, a laptop, and a quiet environment to make some notes on the natural (unprocessed) response of a speaker.

In the specs from Crutchfield, we are told that “R1T-S tweeter has an integrated 6 dB/octave high-pass crossover fixed at 12,000 Hz. The in-line crossover simplifies your installation. The 5.25" woofer has natural roll-off characteristics that allow it to exhibit great acoustic crossover filtering.” Okay, great - the 6dB/octave slope tells us there is a simple single capacitor inside the tweeter’s housing, and they also tell us there is no processing at all on the woofer. If we really wanted to, we could calculate the value of that capacitor since they also give us the cutoff frequency, but that does not really do us any good for this application.

The important info there is that there is the cutoff frequency – we now know what our target is for shaping the woofer’s response. Despite the bit they mention about natural rolloff, the upper-end rolloff of a standard woofer like this is usually anything but smooth (and of course, random peaks and dips in frequency response do not sound good at all).

We want to add some circuitry to control the upper end of the woofer’s response, to do our best to avoid the really radical peaks and dips from natural rolloff. Since the designers tell us that 12khz is the crossover frequency, we really don’t have to do frequency sweeps. If we didn’t have that information, we could, at a moderate volume, sweep up and down through the midrange regions where we would expect the crossover point to be and find the natural rolloff points of each driver based on when the volume starts to noticeable decline on the high end for the woofer and on the lower end for the tweeter. This has to be done at low volumes – sine waves, like those output by a tone generator, heat up voice coils like nothing else and if you expect too much from a driver you run the risk of cooking it.

Not something we need to do here, though, as Rockford publishes that 12khz spec. We’ll assume it is correct and a good crossover point for each driver. We now need to do a little math – we know we’ve got a woofer we want to start rolling off around 12khz; and we can use just a single inductor to make that happen. Inductors (and capacitors) are a simple little electrical components that works kind of like a frequency-variable resistor. The level of resistance they provide varies based on the frequency of the signal fed to them. Inductors offer more resistance the the higher the frequency they are fed, while capacitors do just the opposite and are most resistive at lower frequencies. (At 0hz, or DC, capacitors have essentially infinite resistance and pass no current at all). Like Pioneerisloud mentioned, The12Volt is an great resource. They give us the simplified equation: Inductor value=(1000 x Impedance) / (6.283 x Crossover Frequency). Since the total load of this system is stated as being 4ohms, we can assume that tweeter and woofer are each 8ohm speakers on their own. Plugging in our values, we find that the needed inductor is 0.10611mH – we won’t be able to find that exact value at a store, but we should be able to get close. The only other thing we need to check is that the power handling of the inductor we select is greater than the power of the amplifier we’re expecting to drive the speaker with, otherwise we could melt the inductor. A single inductor in series with a load creates a ‘low pass filter’ – a filter that passes on low frequencies, and cuts out high ones. The value of our inductor and the impedance of the load it is connected to tell us what the frequency is where this happens. The slope, or how quickly the volume goes down above the cutoff frequency, is controlled by the number of inductors or capacitors in the circuit. More capacitors or inductors make for steeper rolloff. The standard rolloff for this type of filter with just one component is 6dB/octave. More complicated circuits give you steeper rolloff and thus cleaner crossing from speaker to speaker, to a point. That is a more complicated issue.

We can do the same thing on the low end – we don’t want the woofer to just flab around trying to reproduce frequencies that it physically cant, or even frequencies that our subwoofers handle. Using a single capacitor, knowing that we are hooking it up to a 4ohm load and we probably want to roll off around 100hz or so, you can lookup the equation and figure out what kind of capacitor value you would need to process the low end, also. Simply putting this capacitor in series with our inductor which is in series with the positive wire coming from our amp, we can create what is called a ‘band pass fitler’. We are allowing a specific band of audio, from 80hz to 12khz, to pass through and are cutting out everything else.

I hope that all makes sense, please feel free to ask for clarification or elaboration if not. I tried to teach as much as I though reasonable, rather than just throwing equations at you.
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