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Old 10-20-2013, 11:53 AM - Thread Starter
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So here is what I have...

 

Amp: http://www.amazon.com/KICKER-DX250-1-WATTS-BLOCK-AMPLIFIER/dp/B004VD3158 : Kicker DX 250.1

Subwooferhttp://www.bestbuy.com/site/kicker-10-single-voice-coil-4-ohm-subwoofer-with-enclosure/9894295.p?id=1218190975541&skuId=9894295 

Amp Kit: http://www.amazon.com/Soundquest-SQ600XS-600-Watt-Blue-Twisted/dp/B0007U0G7U/ref=sr_1_cc_1?s=aps&ie=UTF8&qid=1382250354&sr=1-1-catcorr&keywords=soundquest+600 

 

I currently have the input gain control all the way up and getting pretty heavy bass around 25 volume control on my head unit. There isn't a major difference, if at all going past 26. And I haven't hit any distortion.

 

So my question is, am I close to blowing the voice coil or maxing out at 250 watts? Or is the amplifier keeping the subwoofer from going over 150 watts RMS? If I am truly hitting it's max load at 250 watts ( I can't tell whether it's 150 or 250, inexperienced), am I risking the subwoofer that can handle up to 300 watts? I would like to keep the subwoofer from going over 150 watts, but I have no idea if that's even possible. I'm just trying to understand RSM vs Peak. 

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Old 10-21-2013, 09:47 AM
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You have a single coil 4 ohm subwoofer

your amp puts out 150 watts at 4 ohms

Disregard the RMS stuff. Learn what RMS means and you will see why.

2 things destroy a speaker. Thermal and mechanical.

Thermal: applying either more voltage/current then the woofer can handle and melting a voice coil or supplying power over a long period of time that heats the coil beyond the capabilities of the design to cool the coil and melting the coil.

Mechanical: over driving the speaker beyond its mechanical capabilities through to much power or design and implementation.


So to answer your question, my guess (based on your equipment) is that you are not going to blow your sub. Your amp puts out 150 watts max (use this number based on specs. Even if it's double no matter) at 4 ohms. The sub actually provides a higher impedance than the 4 ohm DCR stated while it is in the enclosure, the frequencies it's trying to reproduce and thermal rise (as the voice coil heats up, the resistance increases).

So with your gain settings (it can be difficult to hear distortion in a sub or rather we are not as sensitive to it.) you are hitting the brick wall of output that amplifier can provide. Having any bass boost or loudness EQ used just makes that max power happen faster.

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Old 10-21-2013, 12:27 PM - Thread Starter
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So, because the Subwoofer is rated at 4 ohms, the amplifier is matching it's impedance at 4ohms instead, making the amp only put out 140 watts? Is this something that's automated between the amp and subwoofer? 

 

RMS Power Rating (14.4V):

  • 4 ohms: 140 watts x 1 chan.
  • 2 ohms: 250 watts x 1 chan.

 

 

After making this post ( and before your reply )  I decided to turn the gain output down on the amp to about 60% of it's maxed load because I was trying to match the wattage on the amp to the subwoofer ( not true after all). But actually it's true max load is really only 140 watts? Meaning I can just crank up the gain output back to max load on the amp after all? Or is that risking the amplifier. 

 

There is a bass boost on the amp, which is turned off. The amp is fixed at 80 Hz so I can't adjust the subwoofer. What I can do is adjust the loudness EQ to -6 to +6 and currently the subwoofer is set to +3 with the amps gain output to 60% of it's max load. 

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Old 10-21-2013, 01:20 PM
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The gain is not a volume knob. It's sole purpose is to match levels with the head unit. Your amp puts out a finite amount of power at 4 ohms, it's rated at 150 watts. So adjusting the gain to match the head unit you can max the gain and hit the 150 watt max early or reduce the gain to hit max when you hit max volume at the headunit.

Any sort of boost mean your amp hits the max earlier.

For every 3 decibel of increased output, you have to double the power. So let's say you are adding a 3 decibel (db) boost at 40 hertz. The q on that is not tight. so you tun up the volume on the head unit to a point where the amp is providing 75 watts. let's say that is at 13 on your head unit volume knob. at 40 hertz for that 3 db bump, your amp is providing the full 150 watts. and for 30-50 hertz probably very close (again these numbers are round, easy to visualize and off the top of my head to help explain.) to the 150 watts. So turning it up past the 13 point does not gain you any increased output out of the amp. What does happen is your amp starts clipping the signal. Distortion becomes much higher. And gives the impression the subs are playing louder.

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Old 10-21-2013, 01:33 PM
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get a multimeter and while your car is running take a DC voltage reading from the positive and negative terminals at the amp. rev the engine to 2000 rpm. take the reading at that point. Does your car put out 14.4 volts?

Most are around 13.6-14.

Here is a little bit of math to help simplify things and maybe make them easier to understand.

Disclaimer:Amps are not 100% efficient. Class D are often 70-80% efficient, Class AB are 30-50% Class G/H are around 50% Just remember that.

My amplifier that I use is a Sundown SAZ1500D. It is rated for 400 watts at 4 ohms, 800 watts at 2 ohms and 1500 watts at 1 ohm loads respectively.

there are 160 amps of fusing on the amp. 4X40 amp fuses.

at a batteries output:12 volts I get a max of 1920 watts (12X160) (volts times amperage equals watts)
multiply 1920 by .8 (1920X0.8) and you get 1536 watts which correspond very closely with what the amp is rated at. And it does put out that power at a 1 ohm load which I run my sub at.

So figure out what your amp is fused to, multiply that by 13.6 that should get you the 100% efficient numbers. Multiply that number by what class your amp is and you have the 2 ohm power output that comes pretty darn close for knowing what your amp is producing. basically halve it for 4 ohms. if it seems lower than what you were expecting, don't worry. You would have to get an amp twice as big as what you have for a 3db gain.

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Old 10-21-2013, 02:17 PM - Thread Starter
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So regardless if I am turning up the amp's gain to max power or if it's at 60% with a 3 db raise on the subwoofer, I'm probably hitting my max load on the amp regardless. To the sound of it, I'm probably hitting max load faster at 60% gain output and 3 db gain then I would if I were to just crank up the gain output on the amp and turn the db down on the subwoofer to 0. At the point where my amp has maxed out the power to the sub, I should start hearing clipping and distortion?

 

I instead need to sit down and figure out the point of where I start seeing distortion and turn the gain output down. The thing is though, I have yet to hit any distortion (as far as I know) with the subwoofer, even at 25+ on my HU's control knob. If I am, it is indeed very hard to tell whether or not I'm hitting any distortion. 

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Old 10-21-2013, 02:34 PM
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http://www.the12volt.com/installbay/forum_posts.asp~TID~85479~PN~1

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Old 10-21-2013, 02:39 PM - Thread Starter
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Thanks

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