Subwoofer amp issues and questions

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LLDeese

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Joined 2007
#1
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 ?????
 
#3
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.
 
#4
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).

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An externally hosted image should be here but it was not working when we last tested it.
 
#5
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,,
 
#6
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
 
#7
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??????
 
#8
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.
 
#9
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????
 
#10
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.
 
#14
Re: Xmax one way linear

LLDeese said:
Linkwitz Transform VS parametric EQ in subamp


Wouldn't these do basically the same,,, running a subwoofer. Making the woofer louder at lower frequencies.
Click to expand...
no.
in the transform, one must design the desired parameters to suit the end result together with the existing parameters. This is all very closely related to Q before and after and F. It cannot be achived by EQing unless one were VERY lucky with some unusual combination.


LLDeese said:
is there a difference in xmax and xmax one way linear. Or is this a way for some companys to make their subwoofers look like they have more travel?????
Click to expand...
it's all down to the difference between cheating and lying.

Xmax is a the lesser of the linear one way displacement from the rest position in either direction. That is unchangeable.
The problem is defining linear, not peak to peak. Note that Xmax is a peak, not an rms value and most SPL and power formulae use rms (=sinusoidal ac).
 
#15
If the amp is rated 250W into 8 ohms then with your drivers wired series you will get 125W to each speaker. It seems like you need to find a more powerful amp to drive them subs.

Maybe try a pro amp, 1 speaker per channnel. Behringer europower seems a popular 'cheap watts' solution.

Cheers,

Rob.
 
#16
Damping factor of amplifiers

How important is the damping factor of an amplifier. Is a 300 watt per channel with a 3000 damping factor better than a 400 watt amp with a 100 damping factor??? Can you tell the difference??? What if the damping factor not listed in the specs does it really matter???
I know damping factor depends on how heavy the gauge of wire and distance hooked between the sub and amp. And it goes down with ohming load.

Some manufacturers do not give the damping factor at all.

Does it really matter???

Thanks so far,,,everyone is a lot of help!!!!
 
#17
Hi,
if the damping factor is greater than 20 at the frequencies you plan to operate at, then other factor will tend to dominate and the amplifier damping factor becomes irrelevant.
eg. for a 4ohm load and DF=20 the source impedance will be 4/20=0r2
If your cables (both flow and return added together) add another 0r2 then the overall DF has become 10 and this will affect the Q of the speaker.
 
#18
Amplifier load power????

This amp is rated at,,,,,,,,,,,,,,,,,
512 watts RMS into 8 ohms @ 0.09% THD, 1,024 watts RMS into 4 ohms @ 0.15% THD


I was told that hooking the two 4ohm single voice coil Infinity Pefect 12.1's in a series would yield,,,,,,,,,,,,,,,,,,
"These should indeed be hooked up in series to create a 8 ohm load. the 500 watts will be divided between the coils."


So each speaker gets 500 watts a piece??????


Thanks,
Larry
 
#19
Re: Amplifier load power????

HI,
LLDeese said:
This amp is rated at,,,,,,,,,,,,,,,,,512 watts RMS into 8 ohms @ 0.09% THD, 1,024 watts RMS into 4 ohms @ 0.15% THD ........... two 4ohm single voice coil ........ in..... series would yield.......... the 500 watts will be divided between the coils."
Click to expand...
somebody is telling you lies.
It is virtually impossible for a 512W amp to generate 1024W into half impedance irrespective of how well it is made.

Yes, the two series connected 4ohm speakers will result in an 8ohm load.
The 512W (if it can still be believed) will be divided between the speakers so each will feel about 256W into their 4ohm impedances.
 
#20
Amplifier power and ohm loads???

If I run an amplifier that is rated at 500 watts into 8 ohms with two 4 ohm speakers hooked in a series they would have 250 watts each going to them.


If I run an amplifier that is rated at 1000 watts into 4 ohms with two 8 ohm speakers ran parallel they would have 500 watts going to each of them??????

Is there any way to hook two 4 ohm speakers to a 1000 watt 4 ohm amplifier and get over 250 watts per speaker without running a 2 ohm load (parallel). Because the amplifier will not run a two ohm load (only rated for 4 ohms or greater).

Thanks for any help anyone can give. It seems like it would be easier to run two 8 ohm speakers thatn two 4 ohm speakers.
 
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