QuestionQUESTION: I bought an XXX XBX1200 sub and amp kit. The amp is 1200 watts peak, but I have no idea what the RMS is. I even called the manufacturer and they couldn't even tell me the RMS. So anyway, I ended up selling the subs because I wanted better ones, but I kept the amp. I currently have 2 12" Memphis Audio 15-PR12S4 subs in a box hooked up to the old amplifier.
The subs sound very good until I turn up the volume on my head unit to 20 out of a maximum of 35. They start to clip pretty noticeably. I've turned down the gain on the amp and was able to get it to sound better but it still doesn't sound as clean as I'd like. Plus, obviously turning down the gain makes them not as loud, and I'm almost positive that they can sound better at a higher volume if I just had a better amp.
So my question is what kind of amp should I get? If you could tell me Brand/Model specific that would be awesome, but I really just want to know what RMS the new amp should have and at how many ohms etc. I don't know much about ohms and I would like to know as much about them as possible (specifically how many ohms my amp and subwoofers are etc).
Finally, if you could tell me what gauge wires to use for Power/Ground and for the speakers. My Power wire is about 8-12 feet long and my Ground wire is about 4 feet long.
ANSWER: Adam,
There are 2 types of listeners. Ones that want good sound and ones that want all the bass they can possibly get. Assuming you want good sound, your amp rms power should be about double the headunit rms power. So, if your stereo, like most, is about 15 - 25 watts rms per channel, then your amp should be about 50 - 70 watts rms per channel. If you are looking for pure bass and do not care about sound quality, you would go for an amp that would max out your speakers the most, safely. With your subs, that would be 250 watts rms per channel. Your subs could handle alittle bigger amp, but you would run the risk of blowing them if you get any larger.
Ohms are a measure of resistance. Speakers are manufactured with certain amounts of resistance to make them work. The less resistance, the louder the sound. So, you would think the less resistance, the better. The problem is that, if the amp receives the negative power with the same resistance as it is putting out, it will blow up the amp. So, you have to have some resistance in your system. Most amps are safe down to 4 ohms. Some higher end amps are safe down to 1/2 ohm. The truth is, the higher the ohms, the better the sound quality of the subwoofer. If you bridge subs, you can raise or lower the ohms, but it is pretty tricky calculating it all to make it work right.
In your case, I would suggest a Rockford Fosgate Prime R150-2, Orion Cobalt C03002, or Clarion APX2121. These are all around 50 or 60 watts per channel at 4 ohms (which is the ohms of your subs). They are good brands and will not clip out on you. Hope this helps, Scott
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QUESTION: So I'm pretty sure I've got a good understanding now, although I have a few follow-up questions. Correct me if I'm wrong: The lower the ohms, the louder the sound, and the higher the ohms, the cleaner the sound. Also with lower ohms, the wattage is most likely higher, and with higher ohms vice versa.
Now, my head unit is 22 watts x 4 channels. So if I wanted the CLEANEST POSSIBLE bass, I would want to go with a 44 watt per channel (88 watt total RMS) amp? But as you said, that really wouldn't provide very loud bass at all. So assuming I wanted a 50/50 ratio of sound quality/loudness would you recommend a 150 watt per channel (300 watt total RMS) amp? I noticed that the amps you recommended were 150 watts RMS. I just feel as if they wouldn't provide me with as much BOOM as I'd like. Then again, your the expert so I'm just kind of throwing the idea out there I guess.
Also, how do I know how many channels my amp is? It has 2 sets of terminals, one for each sub. I'm pretty sure it is related to whether it is single or dual voice coils but once again, you ARE the expert so if you could provide me with a little insight on SVC, DVC, and channels I would be more than grateful.
Thanks in advance Scott
AnswerI understand your position on this situation. Most amplifiers do have adjustable gain controls, so if you wanted to go with a more powerful amplifier, you could always adjust the power down to match your taste. You should expect to pay twice the price. You are correct about the channels, each voice coil requires a channel. If you have dual voice coils, you can combine the voice coils into one channel, but you must calculate the ohm load that is made and be sure that your amplifier can support such resistance. On that note, you can bridge 2 subs into one channel, but you must calculate the ohm load and remember the lower the ohm load, the higher the distortion. The most important thing to remember is to use separate channels for each voice coil and keep the per channel RMS power below the RMS power rating of the sub. Also, 300 watts (rms per channel) will be too loud to actually sit in the vehicle and listen to (it hurts). The amps that I recommended will have plenty of power for your application. The best way to test this, is to go to a local stereo shop that stocks these brands and have the amps hooked up compared to the normal headunit outputs. You will get a very good idea of what I am talking about. Good Luck, Scott
