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I had this Eclipse Aluminum subwoofer, I'm sure you guys remember the SW8122 DVC. These were the really good Eclipse Aluminums before they downsized and downgraded them, IMO the best sounding sub Eclipse made. I decided to sell it and had a guy at work that bought it and the ported box I'd made for it for $200, with the agreement that I'd hook it up to his amplifier (which was already in the back of the vehicle). He pays, gets the sub, and the next day after work we go to hook it up to his amp.

I thought he was at least a halfway serious enthusiast in look of a great sub for his system. Lo and behold, get to the Blazer, and I see the amp. Bostwick MA-4100X Total crap, and only rated to put out 100x4 at 2 ohms, something like 60x4 at 4 ohms, and overrated at that. THEN he says he paid $330 for the amplifier, in which I kept my mouth shut about how much he got raped on that deal. Bridge front and rear amp channels to get all 400 overrated watts to the sub. Sounded decent, though there was an apparent lack of power. I set the head unit flat, adjust the gains w/ a voltmeter, set the crossover, then do some listening. Sounds good until previously mentioned amplifier clipping comes into play. He's happy. Come back this week, he complains that the amp had been getting very hot, and he went to Custom Sound (where he bought it) and they told him not to bridge the amplifier, after all, the channels alone have plenty of power for THAT sub (in which they carry Bostwick, lower level Alpine, the MB Quart Discus series, and other random crap). This thing puts out MAYBE 60 watts per channel at 4 ohms. I told him he was severely underpowering the subwoofer, still trying not to tell him that the amplifier is a pile of shit. So I look and he has adjusted the gains full tilt, bass boost set at 18db, bass boost on the head unit is at maximum, treble at maximum, and dbb (or whatever other bass boost Sony Xplod head units use, something like that) set on. And he's wondering why the amp is hot I offer to sell him an older amp I have and he won't bite on it, which I gave him a very reasonable price. So now we have an excellent, highly underrated subwoofer in a very nice enclosure getting maybe 120W.

Kind of pisses me off that he can't or won't do justice to a really nice subwoofer and box, and that I didn't check this out b/f I sold it. I really wish I'd have put it on this site and sold it to one of you guys, at least you'd respect it for what it is. I got the money for it, though.

maybe direct him here to the site so we can tell him

He doesn't have internet. I've tried every way I can to educate him on the hows and whys, but he's just one of those guys that doesn't care to know. Oh well. That amp couldn't put out enough power to do any harm to that Aluminum, though, I'm safe from the "why did the sub blow" questions.

Nope, it can for sure blow that sub, and amp in the process. If he turns up the gain and starts sending clipping signals to that subwoofer, he is going to blow the subwoofer and the amplifier.

Justin from Detroit wrote:Nope, it can for sure blow that sub, and amp in the process. If he turns up the gain and starts sending clipping signals to that subwoofer, he is going to blow the subwoofer and the amplifier.

agreed.......if you think that amp is getting hot and distorting what do you think is happening to his voice coils?

well I was just at my shop looking at a sweetass dashboard all vinyled up and no where to go when low and behold, a fine ass kia rio comes in, with a dual nob jensen HU, two Legacy 1200w 10's (w0w) and get this....one kenwood ka-524..something like 30wx2 with no lowpass filter on it. This kid pays 95 bucks to get 8g wire run to the rear, a premade box and these POS subs in it, with the whopping 60w going into 2 10's FULL RANGE! I had to stay there just so I could hear it. WOW is all I can say..and that my friends, isn't good.

So Jonathan my friend, it could be worse.

thats a really awsome sub i had one in my mustang when i first got it and it is the best sounding sub eclipse made. you should offer to buy it back and he should get a bostwick or what ever that amp was.

"Nope, it can for sure blow that sub, and amp in the process. If he turns up the gain and starts sending clipping signals to that subwoofer, he is going to blow the subwoofer and the amplifier."

Won't blow that sub. Not in this application. The only thing that kills a speaker is either heat or overexcursion. Which requires overpowering on both accounts. Clipping gets blown out of proportion, it isn't the clipping that damages a speaker, it's the resultant average power increase. Distortion doesn't have any relevance to the issue. Even when clipping, the maximum power increase is double power. A voice coil isn't going to start rocking and moving in crazy directions just because an amplifier is distorting. Harmonic distortion will increase greatly, but it is harmless to a sub. Even if that amplifier doubled power from a square wave, it would still only put out 240W RMS, which I guarantee wouldn't fry that sub. If a 500W RMS sub blows from a fully clipped 120W RMS amplifier, it's because the sub isn't built worth a damn to start with.

When you say you used a voltmeter to set the gains, what do you mean? Like, what did you do?

"When you say you used a voltmeter to set the gains, what do you mean? Like, what did you do?"

I had to assume how much power this amplifier put out (I know, very rough guess considering the "quality" of the amp). P= V^2/R, so to put out 200W RMS on a 4 ohm load, the channel would have to put out around 28.25 volts to achieve it. Since the amp is crap, I set it to put out 25V, which is closer to 150W. I keep a CD with 0db reference tones for setting such things. Basically, I just assumed a nominal impedance of 4 ohms and I assumed the amp would put out 150W on a channel. Rough guessing, not exact, but I'm not really that anal about setting somebody else's gains.

I went to the trouble of using a meter to set the gains, guess at the power, and set up the amplifier, with the guy watching me and me explaining this to him at the same time. Then shortly after, the guy cranks everything full tilt not knowing anything about the amp, pisses me off.