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Old 24th February 2007, 10:37 PM   #1
LLDeese is offline LLDeese  United States
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Location: alabama
Default Subwoofer amp issues and questions

AMC 2100 INFINITY PERFECT 12s Post #1
[AMC 2100] Solid State Amplifier, 2-Channel, 2 x 100w
SPECIFICATIONS
Bridging ModeRated power into 8 ohm (IHF) 250 W
Rated T.H.D. 20Hz-20kHz 0.03%
Clipping power into 8 ohm >300 W
Dynamic power into 8 ohm (IHF) 500 W
2 Channel ModeRated power into 8 ohm (IHF) 100 W
Rated T.H.D. 20Hz-20kHz 0.03%
Clipping power into 8 ohm 115 W
Dynamic power into 8 ohm (IHF) 150 W
Current limit into 0.1 ohm and 1 ohm 32 Amps
Damping factor >200
Input sensitivity for 1W / Rated power into 8 ohm 100mV / 150pF
Input impedance 22 K-ohm / 150pF
Frequency response 20Hz-20kHz +/- 0.2 dB
Frequency response -3dB 5Hz / 110kHz
Signal to noise ratio "A" WTD (ref. 1W / 8 ohm) 100 dB
Separation 20Hz-20kHz >80 dB

Infinity Kappa Perfect 12.1 12" 4-ohm subwoofer
Size 12 -inch
Impedance 4 ohms
Cone Material Aluminum
Surround Material Butyl rubber
Sealed Box Volume (cubic feet) 1
Ported Box Volume (cubic feet) 1.75
Port diameter (inches) 4
Port length (inches) 12.33
Free-Air Yes
Dual Voice Coil No
Sensitivity 96dB
Frequency Response 18 - 0.2k Hz
RMS Power Range (Watts) 75-350
Peak Power Handling (Watts) 1400
Top Mount Depth (inches) 6 1/8
Bottom Mount Depth (inches) 6 7/8
Cutout Diameter or Length (inches) 10 15/16
Vas (liters) 83.28
Fs (Hz) 23.32
Qts 0.44
Xmax (millimeters) 14.15

Compare to more products

* Infinity Perfect 10.1 $149.99
Size 10 -inch
Impedance 4 ohms
Cone Material Aluminum
Surround Material Butyl rubber
Sealed Box Volume (cubic feet) 0.6
Ported Box Volume (cubic feet) 1
Port diameter (inches) 3
Port length (inches) 10.4
Free-Air Yes
Dual Voice Coil No
Sensitivity 94dB
Frequency Response 18 - 0.2k Hz
RMS Power Range (Watts) 75-350
Peak Power Handling (Watts) 1400
Top Mount Depth (inches) 5 13/16
Bottom Mount Depth (inches) 6 1/2
Cutout Diameter or Length (inches) 9
Vas (liters) 32.13
Fs (Hz) 28.35
Qts 0.42
Xmax (millimeters) 14.15
Parts Warranty 3 Years
Labor Warranty 3 Years


I have a amc 2100 hooked to two Infinity perfect 12s. The amp clips off with out warning sometimes. I have tried hooking them in 2 ohm and 8 ohm loads ,,,bridged mono and in stereo. The amp does better in the 8 ohm load but still turns off every now and then and has to be turned off to reset it. The gain is about 2/3rds. the way up. The woofers are in two, 1.5 cubic foot sealed enclosures. When playing them I start to turn them up loud and they sound awsome then a big bass note will come along and the amp will clip. Usually a woofer will distort a little so you know to turn it down,,, but it gives no warning. Please help me,,,,do I need more power???

The amc 2100 is rated 250 watts in a 8 ohm load so is the speakers getting 250 watts a piece or half that, each woofer is 4ohms ?????
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Old 25th February 2007, 02:23 AM   #2
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I have a pair of Infinity Kappa 12.1D subs I use for my home hifi system. They are configured for 8 ohms. They are fantastic! In the past I used a Phase Linear 400 and currently use an AV400. These amps have considerably more power than what you are using. Looks like you need a bigger amp. I'm very impressed with these drivers. They exceeded my expectations! Don
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Old 26th February 2007, 03:53 AM   #3
LLDeese is offline LLDeese  United States
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What kind of enclosure do you have the infinity's in??? Do I need to go down to 1 cubic ft enclosers, right know they are 1.55 cubic ft. I like sealed enclosures, because of their accuracy. How much power per channel would you recommend. Is a 1000 watts in 4 ohms enough to drive both of these single voice coil subs. I want to have enough power to run them to the limit.

Thanks,


I am impressed with these speaker also.
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Old 26th February 2007, 11:27 AM   #4
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I used Infinity's specs for enclosure and port size. The box is 1 cu. ft. and I don't remember what the port is. However, it is documented in the Infinity spec. sheet that comes with the driver.

I wanted mine to look pretty, so I spent some serious time desiging and building. From the pictures you can see I built two enclosures and stack them (the top box is flipped up side down). I used blue grille foam to match my JBLs.

The Phase Linear 220 WPC (8 ohm) power amp was more than enough. It could vibrate the floors & wall. You can actually feel the vibrations in your body when the subs are positioned properly in the room. I have each sub on a seperate channel (Left/right).

Click the image to open in full size.


Click the image to open in full size.
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Old 27th February 2007, 02:46 AM   #5
LLDeese is offline LLDeese  United States
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Your subs look great,,,,,,,,,,,,, I am planning on putting one of my subs in the wall so that just the speaker will have a hole in the sheatrock entering the room. The other sub will be in a closet with a louvered door in front of it. I am hoping this will not hurt the sound,,,,,,some say that putting the boxes of the subwoofer in another room will take away from the sound.. I guess I will find out,,,,

Thanks,,
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Old 27th February 2007, 12:18 PM   #6
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A couple of things to consider. Placing the subs in another room may affect the phasing and will more than likely make the bass quite boomy. You also won't be able to position the subs to get proper sound based on the room dynamics. Moving the subs around in a room has a HUGE affect on the quality of the sound. I can put my subs in an area an it sounds like that are even working. If I move them several feet to a different location they come alive. Don
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Old 1st March 2007, 08:30 PM   #7
LLDeese is offline LLDeese  United States
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Will a amp like the DAYTON HPSA1000-R with phase control help. The one sub would be in the same location it is now but be behind a sheet of sheat rock in a closet with a hole cut in it for the woofer. The other sub would be two feet from where it is know but be in a closet with a louvered door in front of it. Do you think that this would hurt the sound. So do you think the Dayton amp is worth the $400?? If the 1000 watts of power in 4 ohms is powering my two infinity's in a 8 ohm load,, does each sub get 500 watts per channel??????
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Old 1st March 2007, 08:41 PM   #8
AndrewT is offline AndrewT  Scotland
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Hi,
are you running the subs off the same amp as the main speakers?

Where in the amplifier specification does it say that the amp suits less than 8ohm speakers?

Why did you try running it in bridged mono mode when it is already giving problems in stereo mode?

Where did the 2ohm load come from? Is that 4ohm sub//4ohm main?

250 watt into 8ohm is the same as 63.2Vpk and 7.9Apk.
Apply this to a 4r0 resistive load and peak current jumps to 15.8Apk. Either the amp protects itself or it blows up. Make the load reactive and this becomes silly.
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Old 1st March 2007, 09:40 PM   #9
LLDeese is offline LLDeese  United States
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I am running two Infinity Kappa Perfect 12.1's 12" 4-ohm subwoofers off from the one [AMC 2100] Solid State Amplifier, it is bridged into and 8ohm load,250 watts, the two subs are hooked in series to make an 8 ohm load. It runs the subs better like this instead of series ,,,two channels in a 4 ohm load.


63.2Vpk and 7.9Apk????
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Old 2nd March 2007, 06:13 AM   #10
AndrewT is offline AndrewT  Scotland
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Hi,
forget bridge mode.
The amp behaves as if a load equal to half the actual load is applied to the output terminals when in bridge mode.

Your amplifier changes from a theoretical 250W into 8ohm when in stereo mode to 1000W into 8ohm when in bridge mode. When doing this each channel thinks it is driving 500W into 4ohm when an 8ohm load is connected.
It plainy recognises the overload problem and protects itself.
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