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  1. Join Date
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    #1
    Quote Originally Posted by 12vdc View Post
    From what i understand. The speaker box is passive just like any ordinary old model component. It has 3 speakers in a box so that would definitely have a crossover/ filter built-in.. TS wants to plug it but unsure if it would work without damaging the HU's amplifier, so the first thing he should do is check the specs (impedance and power), match it with the car-stero amplifier output..

    In this case, car stero says 4 channel 45 watter 4 ohms
    What he have on hand and planning to install is 4 speaker box with 8 ohms input impedance and 100w max output. Probably the component comes in 4+1 configuration, the +1 is the center speaker.. So if he wants to wire it in the car, he'd normally connect 2 speaker box in parallel 8 ohms + 8 ohms = 4 ohms, so out from 4 speakers, he would make 2-sets of speakers rated at 4 ohms 200 watts each.

    The result... REAR LEFT channnel consisting of 2 speaker boxes and the other side REAR RIGHT channel with 2 speaker boxes.. If he's creative enough to tuck neat the speakers under the seats, i think his plan would be a success..
    Most car audio head units have a 50Wx4 MOSFET built-in amplifier. It's mostly 23W RMS * 4ohms under 1% distortion. Get anything more and your distortion plot will rise dramatically until it's around 20% at 50W. Another thing people should know is that head units are actually 8 channels that are bridged in order to get 23W on all four channels at 4 ohms. This is the reason why you can't bridge the outputs to get something like 2x50W RMS.

    But that's simply a tidbit on my part totally unrelated dito haha..

    Well, if it's the entire speaker box as you outlined above..

    Pwede. No problems there. Parallel connection of 2 speaker compo systems on each channel.

    Problem here is that speaker compo systems aren't really subwoofers. They're just tweeter + (midrange) + midbass in a plastic ported enclosure. When it comes down to it, they won't hit 30hz and that's considering a natural no-crossover slope. A single 10" subwoofer will be more efficient than all 4 6" midbass drivers in reproducing bassy sounds.

    Also, I'm not too sure in wanting to have component systems under your seats. Thanks to the higher frequencies, your ears will automatically locate in your head that your music will be coming under your seat -- in other words, you'll hear music playing below your ass.

    If you want the bass of the midbass drivers in DIY setup. You can always yank them out, try to get a crossover that covers dunno... 63/80hz to 300hz, fabricate a slim-type enclosure for use under your seat.. and voila.. DIY under-your-seat midwoofers. Still, for the cost.. a powered subwoofer might be a more ideal setup.

    Still, kung gusto mo talaga ng bass, there's nothing more ideal than getting a 12" GT5-12 subwoofer (3,000), a ported enclosure (cost depends on installer), some wires, and wire it to an affordable V12 amplifier when you're talking about costs. You can also use 12" Targa drivers to further reduce cost if you'd like.

    Since ilalagay naman niya sa likod ng Revo.. I'll probably get the entire compo set, throw it at the back, get a power inverter.. ayun na yun.. DIY loud and clear vehicle. This is probably the easiest solution if you want a compo set inside a car.
    Last edited by jhnkvn; March 3rd, 2014 at 08:34 PM.

  2. Join Date
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    #2
    wow ang dami ng inputs nyo ah. salamat. nagawa kasi ng kaibigan ko ikabit ung dalawang speakers from a component system. ang ginawa lng nya is connect dun sa amplifier. gusto ko gawin rin yon kaso lng nagdadalawang isip ako baka kasi hindi compatible para sa sasakyan ung component speakers..

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    #3
    dsc_0010.jpg eto po yung likod ng component attaching the speakers

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    #4
    Quote Originally Posted by jncp9886 View Post
    dsc_0010.jpg eto po yung likod ng component attaching the speakers
    Those are what you call speaker wires. Kung ganyan sila.. you're all good. It just needs power. You can tap your stock speaker wires or you can get an an amplifier and wire a speaker wire from it to your speakers.

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    #5
    Quote Originally Posted by jncp9886 View Post
    wow ang dami ng inputs nyo ah. salamat. nagawa kasi ng kaibigan ko ikabit ung dalawang speakers from a component system. ang ginawa lng nya is connect dun sa amplifier. gusto ko gawin rin yon kaso lng nagdadalawang isip ako baka kasi hindi compatible para sa sasakyan ung component speakers..
    Ganito kasi yan.. there's no such thing as non-compatibility in speaker amplification with regards to impedence. So wag matakot gamitin yan. All your speaker needs is power in the form of watts. The wattage it gets depends on the electrical resistance. This is what you call ohms or denoted by the symbol Ω.

    So I'll give you a summary of it:
    1. The higher the ohms is, the more resistance you have. The lower it is, the less resistance you have.
    2. If an amplifier can handle 2Ω nominally, it will handle a load of >2Ω.

    In other words, yes.. gagana yun component system mo sa kotse mo as car head units are 4-ohm stable -- for car amplifiers, it depends but it can go as low as 2 or 1 ohm.

    Now, I do not know why people are afraid of it.. but there's no such thing as incompatibility in amplifier and speaker "matching" thanks to resistivity load.

    So let's say you have a 4-ohm nominally stable amplifier. You have a 3-ohm nominal speaker resistance.

    Will your speaker work? The answer is: Yes. Music does not have a static (not moving) resistance load. It's always moving depending on the waveform of the music such as peaks and dips. It may be 2.3 ohms at 50hz, 13 ohms at 100hz, a whopping 500 ohms at its resonant frequency, so on so forth. Nominal is simply the term manufacturers use that to denote something like the average resistance load a speaker presents to an amplifier.

    So when will your speaker dip to 3 ohms usually? If you push it hard. Once you push it hard, the speaker will need more power and to get that power it'll drop its resistance (remember, less resistance.. more power). Once it starts demanding 3Ω from a 4Ω-stable amplifier, the amplifier will be unstable and will go into protection mode is because the load is too much for it to handle. So unless you're really have a crappy amplifier, all it'll do is shutdown your amplifier.

    Hope that helps.
    Last edited by jhnkvn; March 3rd, 2014 at 11:11 PM.

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    #6
    any kind of amplifier will do ba? paano po ba DIY mg install ng amplifier?

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    #7
    Quote Originally Posted by jncp9886 View Post
    any kind of amplifier will do ba? paano po ba DIY mg install ng amplifier?
    Uhhh... konting malabo yun "any amplifier". Since technically, yes. You can get home audio amplifiers, plug it in a power inverter, and you can run your system there. But nobody does it sa kotse hahaha..

    So what you need is a car audio amplifier or an amplifier that gets its power from a 12V source.

    How to install.. if you plan on DIY, best friend mo si Google. Something like Wikihow will work (How to Install Car Audio Amplifiers: 17 Steps - wikiHow). If you suck at DIY installation, best have a professional car audio installer do it. Last thing you want is cause a fire in your car thanks to wrong wiring.

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    #8
    Quote Originally Posted by jncp9886 View Post
    any kind of amplifier will do ba? paano po ba DIY mg install ng amplifier?
    Any kind of amplifier will do as long as the specs matches your speakers.. Lots of car amps around, the manual will guide you.

    If ever you're planning to install an amp with power coming from inverter(because its 220VAC) i'd strongly discourage you to do. Reason, i have yet to see a perfect sinusoidal wave car inverter, all of them are either square or stepped-sinusoidal w/c are too noisey. Thats doable though with larger UPS with on-line inverter..

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    #9
    Quote Originally Posted by 12vdc View Post
    Any kind of amplifier will do as long as the specs matches your speakers.. Lots of car amps around, the manual will guide you.

    If ever you're planning to install an amp with power coming from inverter(because its 220VAC) i'd strongly discourage you to do. Reason, i have yet to see a perfect sinusoidal wave car inverter, all of them are either square or stepped-sinusoidal w/c are too noisey. Thats doable though with larger UPS with on-line inverter..
    Actually, ayan din nasa isip ko eh. Modified sine waves of el-cheapo inverters are incredible in their distortion plots. That's why I recommended not to go for the cheapest one because we can generally assume it has the least filtration.

    However, noisy as it is, you can still use it. Actually, I've seen a perfect sine-wave inverter.. problem is, it isn't really made for cars but rather for solar installations fitted into a car. But the TS can't go this route.. hell.. those perfect wave inverters will give him nightmares in cost alone.

    In that event, let's just hope his compo system doesn't hum or anything haha.. or heat up.. hahaha.. the internet's full of two camps on this one: one is "it's completely fine" while the other one is "it's disastrous".

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    #10
    salamat sa mga inputs nyo mga sir. will post here some pics if naikabit ko na sa sasakyan ko.

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    #11
    Quote Originally Posted by jhnkvn View Post
    Ganito kasi yan.. there's no such thing as non-compatibility in speaker amplification with regards to impedence. .
    Actually there is.. There's a reason why a transmitter(the amplifier) gets an output impedance to be matched to the input impedance of a sink w/c is the speakers. Same exact reason why the microwave radiation could'nt get pass thru a 2mm wire mesh and you could safely peep outside the mesh without toasting your face while the magnetron transfers its power to the food you are cooking.

    You match the source and the sink to be able to transform all the power to audible wave. What happens when you put lower impedance is that the ampli heats up because of overload condition, power being absorbed and more power is demanded untill the amp gets toasted.. Modern amps have protection from overloads and mostly are thermal overload protection. On the other hand if you match a higher impedance, not all power are absorbed by your sink w/c results to lost energy in a form of standing waves.. Matching may not matter much at lower frequencies, but as you go up into the shorter wavelength from radio to audio to micro and the higher electromagnetic spectrum, even the medium of transmission like wires get its resistance in a form of skin effect.. Another reason why there are cable of different impedance, from RCA, coax, twisted pair, up to the air waves in the waveguide..

  12. Join Date
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    #12
    True on the broad side of things. However, on the general car and home audio side of things, there's no matching on amplifier and speakers. Because more than 95% of loudspeakers will typically be in the nominal loads of 1-16Ω -- they're close enough that matching impedance shouldn't be an issue and insignificant. Head-fi has since resistance load of headphones varies wildly from 16Ω to 600Ω and you try to match them with an amplifier that would minimize its impact on the sound curve of the speaker (hence there's hi-gain and low-gain in some headphone amplifiers).

    For home audio, 8Ω drivers are the most common, 6Ω can also be found and 4Ω is also rather common. For car audio, 4Ω nominal is pretty much the standard. The reason for the lower impedance is that unlike in home audio where we have 220V on tap, in a car we usually get 12-13.8V -- a lot less than what your household plug has.

    As much as I do recommend you optimize your amplifier-speaker combo by trying to get the nominal ratings that best takes advantage of your amplifier. I don't think this should deter anybody from using high impedance speakers. For one, I have a 8Ω driver that's just sitting waiting to be used on my next project. Second, there are people who professionally competes with higher impedance speakers in a car and win.

    I might not recommend people run a 1Ω load to a 4Ω-stable amplifier.. but can you use it and actually play it? Yes, you can. Your amplifier simply anticipates the load a speaker will give out. If the resistance is higher, it'll play. If the resistance is lower, it'll protect. Will you cause significant damage to your amplifier? Not really.. well as long as your thermal protection is working properly.

    Going from 8Ω to 4Ω usually means a halving of received wattage. However, power isn't really significant in car audio. Too many people are led stray by power ratings. Is 100W twice as loud as 50W? No. It's only +3dB more. Many people think: oh, I need 100W of power to match that 100W of speaker RMS but do they when most background listening only sucks up <30W of power? Remember, given all else the same.. 23W to 100W is simply +6.4dB. Whether those additional decibels is important is up to how loudly one listens.

    P.S. Speaker wire skin effect does have an effect but the question is: is it significant? In that light, I'll answer no. In fact, temperature changes would probably yield a bigger effect on our perception of sound. For wires, resistance is king for me. Inductance is too.. but that's more of a PITA as a metric to go for.
    Last edited by jhnkvn; March 4th, 2014 at 02:41 AM.

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