Connecting 2.1 or 4.1 speakers to car's music system

Guys,

Any idea whether it is possible to connect the 2.1 or 4.1 channel speakers(Power Requirement : AC 220V) to the music player which has a headphone jack. Will the car battery bear/support such extenal attachment. I mean whether there is enough strength to give power to such external speakers?

Power consumption-wise, the car battery can support such external attachment. But Power requirement-wise, there is a serious problem, as all electronics in the car runs on 12V DC nominal. This voltage can fluctuate quite a bit as a result of battery charging (14.4V nominal) to less than 10 V, when the engine is being cranked.

There should be an inverter (like we have in our houses, just smaller) that can connect to the battery and convert it to 220V, so that the power supply of the 2.1 speakers can be connected.

otherwise, if the speakers run off 12v internally (you would need to know for sure, to quite some degree of certainty) the inverter and the 12V power supply can both be discarded and the amplifier from the speakers can be connected to 12v. But mostly this is not a do-it-yourself operation, professional help would be needed.

Doing all this, what is being achieved? the 2.1 speakers would generally be less powerful than the HU itself in quite some cases, as the 2.1 speakers rating will be mentioned in PMPO - peak music power output, which is a very misleading term for describing audio output. The crappiest of HUs would probably be better, as the lowest I have seen rated is my own ancient Alpine cassette player, which is rated 35W x 4. This rating is usually RMS (root mean square), a better means to describe the available power (If you dig deeper, even this rating is not for continuous power, but we can come to that later).

In summary, the car will be wired for a car audio system, and it is much better to put a car audio system there than the 2.1 speakers, where theoretically one can put 2.1 after a long R&D effort.

Thanks for the detailed information.

Yesterday, I was reading this discussion in another forum where people have connected such systems, but the speakers supported that voltage in those case.

Some Creative speakers were being discussed which were supported. Another thing they were talking about socket of Cigarttee lighter, which can be used. I am not sure how.

I have an old maruti 800 in which i was planning to do this as I have a few sets of 4.1 subwoofer speakers(Intex, Frontech) lying idle, which have decent sound quality.

but in my opinion its not a good idea... coz it will become messy as the space is limited and the shape and sizes of 4.1 is not according to the interiors...

I am an electronics engineer and not an expert on automobiles. So see my opinion in that context please.

Many speakers like Creative 2.1 come with a external transformer that steps down the line voltage to 12 VAC. I am pretty certain that inside the subwoofer there will be a rectifier/filter circuit to covert this to DC. Now in such cases, you can simply connect a DC source to this AC input regardless of polarity and it should work without issue. The subwoofer connections and the satellite speakers are all normally isolated in terms of their housings so there is no interference with the car wiring if you do that. My own 2.1 speakers at home are pretty loud for my bedroom so I'm sure in the smaller volume of the car the loudness would not be much of a concern.

There are two concerns that I would have in such a case.

1. The mounting - Where and how are you going to mount the satellites in the car? The sub is not an issue because it can stay in the boot area. But that gives rise to another issue. The signal input from your iPod or mobile phone or whatever would normally have to be given to the subwoofer box so there is the issue of routing the input cable to the dashboard area.

2. The car is a very noisy environment in the EMI (electro magnetic interference) or RFI (radio frequency interference) sense. A lot of noise is coupled in through the power input which is coming from the battery. A little DIY would be required to filter it out.

My suggestion to the OP is to actually take your creative 2.1 if you have one, go to your car and connect the battery terminals to the low voltage power input on your sub. Keep all the components on the seat and play it. See whether it sounds acceptable to the level that it would be worth modding the sub for noise filtering and the car for mounting the sats.

Creative 2.1 speaker system will simply not be loud enough for normal driving conditions (for home/PC use it is just about sufficient). Also the power output of such systems is about 5W/channel (subwoofer being 10W or thereofs). This is less than even what the HU gives. In all not worth the effort unless you install amps rated for 30W or higher.

I don't really have much experience of audio in the car but I must caution against being led purely by w/ch type figures even if they are RMS. (BTW I personally do not give any consideration to figures that are not RMS anyway.)

The reason I say this is because a small difference in speaker sensivity would have a huge impact in loudness. Those computer speaker drivers are quite sensitive and 20-30W in total driving them creates a good bit of SPL.

Note That I am not advocating that someone goes out and buys a set. All I'm saying is, if you already have it, it might be worth trying it out. Doesn't cost a dime.

Ok, what is the sensitivity of those speakers? The cost of each speaker is directly proportional to its sensitivity for a given power handling capacity. Low-cost almost always means low sensitivity.

In a typical office or home the PC speakers do sound loud enough. But car is a different thing - the only condition where this will work is when the windows are rolled up and there's absolutely no noise/vibration getting in. Its not always possible to drive with the windows closed - and external/road noise can easily drown even the HU's sound - the PC speakers won't stand up to that. However no harm in trying though.

Rohit, anyways, it is a jugaad. So there is no use being an audiophile in this setup. Just the ability to jack your phone or MP3 stick to the aux cable from the speakers and _any_ kind of sound from the speakers would suffice.

If there is an external power supply, as Emil says, it is very easy to rig up. If the external supply is rectified 12V, it would be easier to purchase a cigarette lighter plug, and wire it suitably to the pin that jacks into the 2.1. (Core +ve, rim negative for the socket and tip positive, wing clips negative for the plug).

Abhishek, If the power supply is something other than 12V, better forget the idea, and equip yourself with a used HU of modest price. If the input is indeed 12V AC, you could try it out, for whatever it is worth.

Agreed - but what's the point of doing this exercise when anyways its not going to be effective when most needed - i.e., heard reasonably well while driving the car? Anyways - I guess its not for me to decide whether to go with it or not - let Abhishek take the call.