QuestionQUESTION: Alright i just got my car stereo sytem installed, Sony head unit and four alpine speakers. I believe i need an amplifier because the head unit shuts off when i put the volume over 28. The head unit is 52watts x4,the front speakers are 55watts RMS and the back are 50 watts RMS so i think already the speakers are not receiving enough power. Im getting a 1000 watt amp http://www.onlinecarstereo.com/CarAudio/ProductDetail.aspx?ProductID=20668 . I also want two subwoofers, but i am confused about all these watts and rms as i am new to car audio. I have a two part question for you. Do my speakers need an amplifier? And if i get the amplifier that i have linked above will i need to get a second for subwoofers?
-Matt
ANSWER: Hi Matt,
It's true that your Sony head unit can't push the Alpine speakers to their full potential, but that doesn't have anything to do with the head unit shutting off. The power rating of the speakers doesn't affect the head unit in any way. As long as they're 4-ohm speakers, and there's no shorted wires or wiring errors, the head unit should work perfectly well even if you're using 200-watt speakers.
If the head unit audio is shutting off, but the display is staying on (possibly with a "failure" message), that points to a defective speaker or a shorted speaker wire. If the head unit is shutting down entirely (no sound, lights or display) then the problem is in the power wiring, not the speaker outputs. Usually this points to a poor connection in the yellow power wire or the ground wire. If you had it installed professionally, I'd call them up and make an appointment to have it checked. I can tell you with 100% certainty that if the head unit is not defective, and installed correctly, then you do NOT need an amplifier to keep it from shutting down.
That doesn't mean that you won't want to purchase an amp for your front and rear speakers anyway. The actual RMS output of the head unit is probably closer to 20 watts than 52 watts, and it will have a higher distortion and narrower frequency range than a separate amplifier. If you want to get the most from your new speakers, then you'll want to connect them to an amp. You just don't need an amplifier to correct the problem you're having with the head unit.
The amplifier in your link is actual much more power than you need for your current speaker system. There are many excellent amplifiers available rated around 50 watts RMS per channel at 4 ohms. Any of these would work very well in your system.
If you want to add subwoofers to the mix, you will definitely need an amplifier for those. Usually, the best amplifier choice for a subwoofer system is a mono amp; the best option for front and rear speakers is a multi-channel amp. If you want to use a single amplifier for your front, rear and subwoofer speakers, you can find several 5-channel amps made just for that purpose. Typically they'll have four channels at the same power rating, for the fronts and rears, and a single channel with a higher output for a sub.
Hope this helps!
Brian
---------- FOLLOW-UP ----------
QUESTION: Thanks for answering my question it helped me out alot. I have one more qeustion though. The amplifier i had in my link, even though its more power than i need i would like to buy it because in the future if i want to upgrade to more powerful speakers, i have a amp with high rms. Would it be bad for my system in any way to use this amp? I just heard that its a wicked amp for a great price.
AnswerMatt,
If you do use the amp, you'll need to be very cautious. That amplifier has more than enough power to blow your speakers if you push them too hard. Set your gains carefully, and turn it down if the speakers start to sound strained or distorted. It's a good idea to switch on the amp's built-in high-pass filter, so that you're not running deep bass to the speakers.
Brian
