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SUB HELPP please!

 

New member
Username: Abish563

Post Number: 1
Registered: Apr-11
ill try to make this as simple as possible.. my subs are 2 new 12'' kenwood w-3012
there in a nice dual box

these are the specs
•12" 4-ohm subwoofer
•textured polypropylene cone with urethane foam surround
•power range: 50-400 watts RMS
•peak power handling: 1,200 watts
•frequency response: 39-300 Hz
•sensitivity: 86 dB
•top-mount depth: 6-1/4"
•sealed box volume: 0.75-1.75 cubic feet
•ported box volume: 1.0-2.0 cubic feet
•warranty: 1 year

My amp is a Kenwood KAC-7202 a little old but still good and gets the job done.. these are the specs.

•two-channel car amplifier
•150 watts RMS x 2 at 4 ohms (230 watts x 2 at 2 ohms)
•460 watts RMS x 1 bridged output at 4 ohms (4 ohm stable in bridged mode)
•high-pass (12 dB per octave) and low-pass (24 dB per octave) filters variable from 50 to 200 Hz
•selectable bass boost (0-18 dB at 40 Hz)
•cooling fan
•MOSFET power supply
•Tri-way capable (Tri-Way crossover required)
•CEA-2006 compliant
•preamp- and speaker-level inputs
•preamp outputs
•fuse rating: 40A x 1
•8-gauge power and ground leads recommended -- wiring and hardware not included with amplifier
•15"W x 2-7/16"H x 11-5/16"D
•warranty: 1 year

with this all being said and done since its only 300rms and my subs are 400rms each i can turn everything on this amp all the way up without ever causing distortion or blowing them? it sounds like a dumb question because i think i know the answer, ive had my amp turned up all the way for a few days now and it sounds pretty good in my BMW i just wanna know if ill run into problems pushing it all the way turnt up
 

Silver Member
Username: Alonzoub

Post Number: 108
Registered: Apr-10
Depends what you mean by ALL THE WAY UP. The gain knob on an amp is NOT a volume control, the gain is meant to MATCH the output signal of your headunit to the amplification level of your amp. That being said, if you just crank the gain, you WILL still clip you amp. When you clip an amp you can easily surpass the RMS rated output and not only is that bad for your speakers, the signal is dirty so you will burn them up.

Your amp is rated to put out 150 watts RMS @ 4-ohms, your speakers can handle 400 watts RMS. You are most likely clipping the s**t out of your amp and putting out >200 watts of clipped signal but your subs are taking it because of how much more power they can handle. It is just a matter of time before they go. Your subs are rated to handle 400 watts of CLEAN power, your are feeding a severely clipped signal, which lowers their power handling due too poor cooling.

Turining your boost up just makes the problem worse.

Read this: http://www.bcae1.com/2ltlpwr.htm
and this: http://www.bcae1.com/gaincon2.htm
 

Silver Member
Username: Alonzoub

Post Number: 109
Registered: Apr-10
**fixed links
Read this: http://www.bcae1.com/2ltlpwr.htm
and this: http://www.bcae1.com/gaincon2.htm
 

Silver Member
Username: Makinblak

Monroe/Monticello, La/Ar

Post Number: 577
Registered: Oct-10
A simple, jankier way to set your gain is to crank up your bass and sub-out all the way on your HU and turn the volume up as loud as you would ever crank it. have your SSF and LPF set already to the apropriate settings. Now, with the subs firing directly at your face, crank the gain all the way up and back down off of it until you just barely hear the subs start to fall off. Then turn up the gain maybe 10 degrees. It will get you close if you don't have a DMM. If you have a DMM, do it with that!!
 

New member
Username: Abish563

Post Number: 3
Registered: Apr-11
so with that alll being said i should do what with my amp? it doesnt sound like its distorted and the subs hit fine, are you telling me to turn it down? or just the bass boost down? which is only at set at 9 out of 18 if i dont turn it down my subs are going to blow? that doesnt sounds possible if tha amp doesnt exceed my rms for my subs and the speajkers for my car havent popped or sounds like there under pressure,
im still new to the whole sub thing i just dont wanna see them blow
and id like them to last
-thanks a lot for the help everyone
very apperciated
 

New member
Username: Abish563

Post Number: 4
Registered: Apr-11
im not near my car aat the moment nor will be for a while, or i would try wht mack said I JUST talked to my friend and he said that im perfectly fine with having it where its at, he has a type R and an amazing amp so i would think hed know what hes talking about but he also might be a JACKASS,i would rather have other peoples opinions
 

Gold Member
Username: Kyle_lowe

Post Number: 1302
Registered: Apr-06
the safest bet would to get your hands on a dmm and set your gains as close as possible with that

a type r is a decent subwoofer, but just having one in no way means your friend knows what he is talking about. I would even guess that he in fact does NOT know what he is talking about if he just said you are fine to just crank everything up

simply put, do not just crank everything up
do it right the first time if you want your equipment to last

a bunch of good, well organized info on this site here
http://www.glasswolf.net/papers/index.html
 

New member
Username: Abish563

Post Number: 5
Registered: Apr-11
also people keep telling me not to turn up the gain? i dont have any knobs tht say gain? i have bass boost but no gain? what do i need to turn down and what should stay the same? should my input sensitivity stay around 1? or 0.5.....
 

Silver Member
Username: Makinblak

Monroe/Monticello, La/Ar

Post Number: 579
Registered: Oct-10
I used to think the same thing..... just crank the gain all the way up and it will be louder! And I blew subs just as fast as I blew amps. Now I know better. Youre freind may think he knows what he is talking about and i'm sure he means well, but He is ignorrant.

Do not have the bass boost up past half-way on the amp. That is the absolute max it should be. BASS is bad. POWER is good.

You can't really hear the distortion or clipping, Most people can't, and it doesn't help you're a NUBE... but your subs and amp can feel it, and eventually, you can smell it.....which is bad.

If your amp's gain is all the way up, you are sending AC voltage through your amp and to your subs, which = death. DC is what you are looking for. clean DC. Which will come from a properly set amp.
 

New member
Username: Abish563

Post Number: 6
Registered: Apr-11
okay what is GAIN?!im sorry im a noob, i appologize lol this little gain switch you guys talk about i dont have one on my amp? i just looked at my amp and if i do is there an alternative name? all i see are input sensitivity,bass boost, and the frequency knobs

but im sure i cant be harming my subs with a 300rms amp if each sub can easily handle 400rms and the amp only has 920watts
also my bass boost is at 9 out of 18 so that being said should i turn it down? you said never go passed halfway which is wat its at now
 

Silver Member
Username: Makinblak

Monroe/Monticello, La/Ar

Post Number: 581
Registered: Oct-10
Yes! INPUT SENSITIVITY
 

Silver Member
Username: Skies

Tofino, British Colu... Canada

Post Number: 930
Registered: Aug-05
"If your amp's gain is all the way up, you are sending AC voltage through your amp and to your subs, which = death. DC is what you are looking for. clean DC. Which will come from a properly set amp."


You mean AC is what you are looking for, DC waves is what kill subs.

And definitely just use a DMM, so much easier!
 

Silver Member
Username: Alonzoub

Post Number: 111
Registered: Apr-10
yea, gain = input sensitivity = level. Its all the same, basically as i said before, different head-units put out different voltage signals so amps where made with this little knob (sensitivity in your case) that will let you dial in the correct voltage. If you don't know how to set that knob correctly and you just turned it to its maximum level, then you are most likely driving your amp too hard.

"that doesnt sounds possible if tha amp doesnt exceed my rms for my subs". It is possible because the rated output of your amplifier is CLEAN power when your gain is set correctly, if you don't set it right then you mmost likely aren't getting clean power and you are getting MORE power than the rated power.

To make things alot more simple with setting gain (input sensitivity), follow METHOD 3 on this website: http://www.thesuicidaleggroll.com/gain.htm

A DMM is a Digital Multi Meter, you can buy one at walmart for $15 if you don't have one.

As for as the calculations got for your case...
Power Desired = 150 watts
Impedance = 4-ohms

Voltage = sqrt(Power * Impedance)
V = sqrt(150 * 4)
V = 24.5 Volts. This is the voltage you will be trying to acheive.
 

Silver Member
Username: Lord_huggington

Ontario Canada

Post Number: 362
Registered: Oct-10
You're thinking of the sub/amp relationship wrong. They don't really have one, it's more-so the box that's in the relationship.

Imagine the amp on its own, does it care which sub you're using? No. You're going to cause distortion with any sub )and any amp) if you turn up the gains all the way. Just because it sounds "good" doesn't mean it's not distorting.

The higher the gain, the more the distortion. Dirty power is what will kill a speaker, it will make a speaker move out of its allowance.

It should have 4 dials - EQ, gain, subsonic filter, high pass filter.

The input sensitivity should be matched with the amp, and you'll need the tools for it.

You actually have 230W to each sub because 2 single 4-ohm voice-coils wire into 2 ohms. If they're D4's than they're wired into 1 ohm and they'd be killing your amp, so they're obviously single's.

Might as well go to a shop and ask for proper tuning.
 

Silver Member
Username: Lord_huggington

Ontario Canada

Post Number: 363
Registered: Oct-10
Bass boost isn't gain. Bass boost is EQ, and some amps have an external bass boost, as in a seperate component that you can wire from the amps location to the listeners location. My Kenwood had one.
 

Silver Member
Username: Makinblak

Monroe/Monticello, La/Ar

Post Number: 582
Registered: Oct-10
Umm... no skiez. Correct me if im wrong but dc is what im looking for. AC kills car audio.
 

Silver Member
Username: Lord_huggington

Ontario Canada

Post Number: 366
Registered: Oct-10
Um... was my fluckin' post deleted? I'm going to go ape shiz up in this bish if it was.
 

Silver Member
Username: Alonzoub

Post Number: 112
Registered: Apr-10
You want clean DC voltage at the power supply of the amplifier. That is as fas as DC signal goes in car audio.

Sound is completely AC voltage, hence the "waves" created by the speaker. The alternating voltage is what causes speaker movement and a clean AC signal will not have any "flat" areas. These "flat" areas are also known as clipping, and cause your signal to become dirty.

From http://www.bcae1.com/ :
Upload

The white line is a clean sinusoidal wave, the yellow line is a clipped wave which causes distortion and poor voice coil cooling. The short periods of flat voltage can be "considered" DC signal.
 

New member
Username: Abish563

Post Number: 7
Registered: Apr-11
Upload

what do i need to change in this picture?? this is my amp and this is how its set up.. what should the input sensitivity be at then? since all the way up is to much?and are my frequency ones ok?
 

New member
Username: Abish563

Post Number: 8
Registered: Apr-11


what do i need to change in this picture?? this is my amp and this is how its set up.. what should the input sensitivity be at then? since all the way up is to much?and are my frequency ones ok?
 

Silver Member
Username: Makinblak

Monroe/Monticello, La/Ar

Post Number: 585
Registered: Oct-10
what box do you have your subs in? ported or sealed? how big? do you know what it is tuned to if it is ported? What kinda music do you listen to mostly?
 

Silver Member
Username: Makinblak

Monroe/Monticello, La/Ar

Post Number: 586
Registered: Oct-10
Huggi, there are 2 "sub helpp" threads
 

New member
Username: Abish563

Post Number: 9
Registered: Apr-11
its a sealed box not ported but im not to sure what the size is and mostly Rap now
 

Silver Member
Username: Alonzoub

Post Number: 113
Registered: Apr-10
abish are you even clicking on the links im giving you? Why bother posting if you aren't going to read the information people give you?

As I said before http://www.thesuicidaleggroll.com/gain.htm METHOD 3 on this website gives you a complete breakdown on how to set your input level (sensitivity/gain..etc).

As for the other settings, this is what I would do:
Bassboost: under 3dB
Low Pass Filter: anywhere between 60Hz and 100Hz (whatever SOUNDS BEST to YOU)
High Pass: doesnt matter you arent using it.
Filter Switch: set it to LOW
Operation: set it to MONO

Im trying to help you out so please read that link I gave you before posting again.
 

Silver Member
Username: Makinblak

Monroe/Monticello, La/Ar

Post Number: 587
Registered: Oct-10
X2 do some reading. We have told you everything to get started
 

Bronze Member
Username: Abish563

Post Number: 12
Registered: Apr-11
btw why the hell would i set it to mono? thats 1ch or Lch? whhy is that good?
 

Silver Member
Username: Alonzoub

Post Number: 146
Registered: Apr-10
Are your speakers hooked up one to each channel? If they are you need to wire them in series and bridge them across both channels.

Its always best to keep the sub-stage mono because having 2-subs playing different signals will cause cancellation and sloppy bass.
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