Printer Friendly Forum Posts - max gain, low output at 2 ohms

Whats going on people. i registered here for some help because i didnt know who to turn to. i dont want to go to some installers around my way telling me i a)need bigger and better amp or b)need better subwoofer or c) need a ported or vented enclosure.

i have installed numerous audio systems on my own cars but i have never experienced something like this. makes me feel very "noobish" because i think i used cheap amps. so because of this i dont know if its my amps, the amps settings, receiver settings or the subs or enclosure. :(

im using a kenwood receiver, 2 Sony XM-1S amps at 2 ohms per sub and 2 kicker comp vrs 12inch dual dvcs at 4 ohm.

each sub is ran in parallel to its own amp for a 2ohm load at 500watts rms (supposedly).

here is the situation. the amps gain is set to almost maximum, bass boost to half way and the bass is clear but its still not loud at all. the receivers bass is set to +3 which maximizes at +15. the amps stay cool to the touch even after playing for a couple of hours on trips at max sound. sound is clear but i always lower the bass setting on receiver to be sure i dont compromise the subwoofers life. as soon as i hear the car rattling i lower the bass just to be safe because the gain is so high.

it sucks because i HAVE to have the gain this high to hear any bass and even then with receiver powered interior speakers the bass is overwhelmed; even at the supposed 1kwatts.

just for reference, i am using 0 gauge wire from battery with 100amp inline fuse. then a block for both amps with 2x60 amp fuses for each amp. i was thinking maybe the 100 amp in line fuse form battery was holding it back but then again, i had this install professionally done. i dont know what gives.

i was thinking of upping the amps to 2x Kenwood KAC-9105D Mono subwoofer amplifier -- 900 watts RMS x 1 at 2 ohms--- one for each sub.

with this amp powering each sub at 2 ohms i was thinking of keeping the gain to lowest possible and bass boost off. i just want to give these subs the maximum power they can handle and then some. i never distort my audio. i just want clear thumping jelly vibrating bass that can overpower my vocals when it needs be. does that make sense?

any help you guys can offer will greatly be appreciated.
thank you :)

Check your polarities, and not just the marking on the woofers. Use a battery to check the polarity of each voice coil, and make sure everything is in phase. Then make sure the signal going to both amps is in phase and that the amp wiring is correct.

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DYohn] wrote:

heck your polarities, and not just the marking on the woofers. Use a battery to check the polarity of each voice coil, and make sure everything is in phase. Then make sure the signal going to both amps is in phase and that the amp wiring is correct.

ditto

thanks for replying. yeah, everything is in phase and wiring is good. had the installer check everything again after i checked it myself to see if he was trying to screw me over. its all good. he actually said though, the amps arent powerful enough. thats why the gains need to be set so high. we changed the xover to max on amp and started using the receiver to adjust per song. max on amp is 300 i think, dont remember off the top of my head. then used 120 on receiver.

another guy at a different shop told me that i need a vented box. but that would just give me audible bass, i want hard thumping vibrating bass from my sealed.

those subs are rated at 400W rms and 800W peak. so 500 watts rms per sub is plenty of power. Try decreasing the xover to about 100-150 and see if it makes a difference. what I would also check is to make sure the correct pushin terminals are paired together. 1 set has a white dot on them.

another ? what output from your head unit are you using? front or rear or do you have a sub out that may be at a low level?

I have the older kenwood 9103d amp pushin a kicker L7 15" and it knocks, the newer amps are running 90 amps though so u would need new fuses on ur dist. Block. Have u tried running your lpf around 65-80 and lowering your gain. Also is your enclosure big enough

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Mastermindz

thanks for everyones input. just checked the wiring again and everything is fine. i dont understand.

my head unit is the kenwood kdc mp642u, maybe this head unit doesnt cut it for the signal? maybe my voltage isnt up to par? i dont know. its a 97 jetta glx vr6. my llights dont dim with heavy bass unless the gain is all the way up to max and even then the bass is at 0 at moderate sound volume. maybe close to half way volume. deep heavy bass on rap i got to -3 and the vocals still overpower my bass. on trance or rock the bass is minimum +3 and still vocals overpower my bass.

im literally lost. the subs are 12cvr124, dual 4 ohm coils.

im thinking of upping the amp to two audiopipes AP15001D for each sub at either 2 ohms or 4 ohms. depending how much power it "sounds like it has".

help :(

just found this for my head unit..

â€¢     Maximum Output Power : 50W x 4
â€¢     2.5V 3 Preouts
â€¢     Source Tone Memory
â€¢     Rear AUX Input with Input Sensitivity Adjust
â€¢     Attenuator (-20dB) with Smooth Volume Return

2.5v preouts, could that be the cause?

mastermindz wrote:

I have the older kenwood 9103d amp pushin a kicker L7 15" and it knocks, the newer amps are running 90 amps though so u would need new fuses on ur dist. Block. Have u tried running your lpf around 65-80 and lowering your gain. Also is your enclosure big enough

tried that. played with the xover multiple times from hu to amp and vice versa. no difference in loudness except muddiness.

blanx218 wrote:

another ? what output from your head unit are you using? front or rear or do you have a sub out that may be at a low level?

it has a sub out that im using. the output volts is 2.5. i did some research and it sounds like that is divided by the 3 sets of outputs it has which is kind of low. that would explain the high gain/bass boost required.

the cheapest route ill attempt either today or tomorrow is upping the inline fuse from 100a to one with at least 120a. each amp is 60amps which is fused accordingly with the distro block but the inline fuse is set to 100amps.

thats the cheapest route to take and hopefully itll add the extra oomph i cant seem to gain from the settings.

let me know if the inline fuse is the proper way to go before attempting to replace amps and/or receiver.

do you have a DMM?
check what the actual LOAD is on the amp, test the ohms at the speaker terminal to make sure.

Also you may try a "live" test to check polarity.
Simply play a song with bass at moderate level and unplug one of the woofers and listen closely.
The bass should drop if the woofers are in phase.
if the bass stays the same or increases then the woofers are out of phase, reverse the positive and negative of the woofer and try again.

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icearrow6 wrote:

do you have a DMM?
check what the actual LOAD is on the amp, test the ohms at the speaker terminal to make sure.

Also you may try a "live" test to check polarity.
Simply play a song with bass at moderate level and unplug one of the woofers and listen closely.
The bass should drop if the woofers are in phase.
if the bass stays the same or increases then the woofers are out of phase, reverse the positive and negative of the woofer and try again.

i dont see how that will work. i did the battery test and it was good. but the way you are suggesting wouldnt work. if i unplug one sub it will just stop working. each sub is connected to its own mono block amp/ sony xm-1s per sub.

either way the installer tested everything out when i first brought it over complaining about it a while back. i just have to do the dmm check but after researching the preamp output voltage i figured that is what might be holding it back. higher preamp volts would require less gain on amp and give it a cleaner signal.

maybe i misread something?

What icearrow is saying is legit as a possibility...possibly meaning-wiring woofers out of "wiring" phase will improve bass sound. just try it, and report back
Beyond that, being it is you know some audio, are you not expecting too much from your product? Sony can play some bass, but it wont rock the house down. Expectation level shouldnt be too high... Otherwise put- if you were using a different brand, there could be more question as is to why your not droppin bottom:)...

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ohhh i see now. ok ill try that. i tried the phase from the head unit from normal to reverse and back again. it did sound a bit different, more boomy but not much difference. no one else can tell the difference but i can since ive been listening to it for about a year. ill try reversing the wiring and see how it is. ill also do thicker gauge wire inside the box because its using 10gauge i think, it looks thin. im not sure if thats sufficient for 500 watts rms @ 2 ohms per sub so maybe that can help a tad bit a long with the 120anl inline fuse up from 100amp. we'll see.

i spoke to my mechanics audio guy and he suggested a preamp line booster first instead of switching out hu and amps. im just afraid of amplifying the 2v will result in inaudible clipping which will blow my subs. i can see where the booster would help because i need the gain maxed out and the bass boost near halfway to get some decent bass out of it. those puny amps are drawing way too much power at full gain and halfway bass boost so im not sure. with max gain my amps are still cool to the touch so thats another thing thats making me lead to the preamp voltage not sufficient for these amps maybe?

i think the best bet as of now, after upping the inline fuse, speaker wire and reversing the polarities would be to just change the amps to more powerful ones unless it is the 2.5v that isnt sufficient for this particular amp model. cant find any information on preamp output level required for specific amps to sound best. so its like an expensive trial and error :(

on a side note, i honestly thought that the sony xm1s would be good because i had a rf100a2 in 2 ohms bridged to a 10 inch kicker L5 and it seriously pounded deeper and harder than this set up. that amp wasnt 2 ohm stable so i just lowered the gain to where it wouldnt fry eggs on the heatsink and it was good to go lol.

sorry for the long post but thanks to everyone for helping me out here.

I would try an eq or pre-amp I'm using a clarion eq and it's boosted my output from 2v to around 7v so my gain to my bass amp is only 1/4 way up and it knocks good

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Mastermindz

I use to recommend boosting line voltage all day and night. I do, always have, always probably will. However, I quit making the recommendation because it comes with some discretion. If you know about it, rock it. Some of my installs done for friends using preamps, electronic cross overs, well they had a chance to hear their systems with and without the devices, ALL can not live without now. That's just food for thought.

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Say Manooti, lets say u wanted to line boost. A simple line driver I have found to be odd to use. 1 dinch of a turn on the gain from the min is all thats needed from one of those things. I like control, spending around 100 bux on any preamp(1/2 din module used in the dash) is sufficient. Spend a lil more and get a parametric version and u get all the control. Soundstream makes some killer devices you may find suitable. I use clarion cause its mellow and all the hz levels it controls are right up my alley. Then, I never achieved the sound I really wanted in a vehicle until I added my first electronic x-over. Unfortunately there were times that I had to pop the trunk at a red light and run to the rear of the vehicle to make a adjustment.... which is why I use preamps now....

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"I use to recommend boosting line voltage all day and night. I do, always have, always probably will. However, I quit making the recommendation because it comes with some discretion".

Yes, you should quit making the recommendation. Driving the crap out of the input stage isn't the answer. The gain on an amp is to match the HU to the amp. If you correctly adjust the amps www.bcae1.com/gaincon2.htm your HU can drive your amp to full power. If it is still not loud enough you need more power, more speakers or more efficient drivers. Preamps do have their time and place, but have seen them more of a bandaid for bad advise and installation. Line drivers are useful for 20 amps in an SPL setup. You might be boosting the level of both music and noise!

Correctamundo - the concept of driving the input voltage is not what I am trying to sell here... band aid? In my case it's life support! Dare to ask why? Or do you know?

Plus, I have led many people to a greater appreciation for it's use by my recommendation! Lets see what manooti thinks if he chooses to try it out! After he asses the device, our opinions wont matter any more.... except you will be wrong and I will be right!

This guy is going to appreciate the addition of a external device in his sytem, reason: He is looking for more. Some people are content with the sound level given by using only amplification and it's on board passive filtering options...

Now, your confidence in "enough power" only leads me to believe you are unfamiliar with this concept I am trying to point out here.

Your statement may hold water if you were being judged by a SQ comp judge who passes judgment at a whopping wha.. 115db max? Ya, ok, play the competition cd and run the RTA.... -OOPS! forgot about that...
30 band EQ, I wonder what that is designed to do? How many Hz levels are analyzed during judgment using a RTA? You're trusting the speaker locations to deliver the whole enchilada on a silver platter?(meaning- "0Hz" on all 30 bands)

SO, I can only produce testimony as proof that there is a beneficial way to improve most sound systems with the addition of a external device- which alters the input signal received by the amplifier.

To be clear here, I am not promoting the signal boost band wagon.

However, I will declare that altering the input signal with a external device is a beneficial method of optimizing the sound of ANY system.
I do not think it is rocket science to properly install and utilize these devices.
Any unsatisfactory results from use I would relate to user error.

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ianarian, what in the world are you talking about?

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DYohn] wrote:

ianarian, what in the world are you talking about?

wow, i missed a lot. i just read the last two posts and it seems this topic ended up somewhere waaaaayyyyyy far from where it started. I thought this was about low power output. Now the conversations is about RTA's and 30-band EQ's?
Anyways, going back to topic:
a line driver would help only if your amplifiers need to have a strong signal (3 volts RMS or more). Is the operation GAIN range at least 1 volt RMS?

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DYohn wrote:
ianarian, what in the world are you talking about?

Dyohn: Thanks for asking!

This problem in question would benefit from any form of enhancement to the signal. Best option would be a 3-way electronic x/o. 2nd to that, a preamp. A line driver would be the last consideration.

Best of the best systems do not happen with a deck-amp-speaker "club trio" configuration.


      I feel like a salesman...

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ianarian wrote:

This problem in question would benefit from any form of enhancement to the signal. Best option would be a 3-way electronic x/o. 2nd to that, a preamp. A line driver would be the last consideration.

Best of the best systems do not happen with a deck-amp-speaker "club trio" configuration.

I beg to differ. The best of the best would involve as little signal processing as possible. Adding a crossover or a line driver will not necessarily do anything to improve the sound quality, and in general a line driver will always make a system more noisy. Adding a "preamp" is the exact same thing as adding a line driver - a line driver IS a preamp. Please give me an example of what you mean by "preamp."

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thanks for everyones input on this. i couldnt get anything done yet because of financial strain. my cousins father told me to teach his son how to drive stick so now im without a clutch. he wont even pay for it. anyway, about 2 weeks ill probably have money to get a line driver and see how it is.

the amps are now at full gain with the bass boost up almost half way. no distortion is heard but it still not enough power. if i put the gain at 1/2 way and bass boost max the subs dont even move. reverse polarities still nothing. it has to be the amps needing more input voltage. damn sonys :(

if the line driver dont cut it or gives out too much distortion i guess its time for new amps. ill keep you guys posted though.

ianarian wrote:

DYohn wrote:
ianarian, what in the world are you talking about?

Dyohn: Thanks for asking!

This problem in question would benefit from any form of enhancement to the signal. Best option would be a 3-way electronic x/o. 2nd to that, a preamp. A line driver would be the last consideration.

Best of the best systems do not happen with a deck-amp-speaker "club trio" configuration.


      I feel like a salesman...

didnt see your post till now. which would be the midrange performance, not too expensive with minimal clipping?
and any links to these devices? thanks

K.I.S.S. = Keep it Simple Stupid.

EVERY and I mean EVERY electronic component WILL add to the Total Harmonic Distortion. It may be a small amount, but EVERY component that you add to the signal path WILL modify the signal.
So for every additional component that you consider adding you have to look at the trade off and decide if its worth installing it.

Stop confusing the poor guy.

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EH EM.... Sorry fellas, vacation in Hawaii....Aloha!

Dyohn: by preamp I mean: a 1/2 din module usually containing Vol./Fad./Sub Level/and typically a few different frequency level controls.

Boats, motorcycles and trail rated, off road vehicles are instances that I will happily agree to possibly not needing signal control-(.)(.)

Icearrow: +0.003% THD worthy of mention? Who is confusing who?

I need a recap!
The issue at hand is balancing between high and low levels correct? What is powering the high's? ______ Are the speakers stock by chance?

In the event that you feel the sudden urge to rid the amps, DIBS!

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I'm 100% with David and Icearrow 6.

"Best of the best systems do not happen with a deck-amp-speaker "club trio" configuration."

This is just a flat out false statement.

"This is just a flat out false statement."

Flat-out? Straight past good ol false, right into the abyss.

Ok, well it is difficult to argue with logic like that. First thing that comes to mind is some verbal insults, next may be a decision if its worth a response. Ah, what the heck,--Let me tell ya like this here:

Bring your unprocessed signal to a official SQ competition...Good Luck!

I'll bow down and call you master if you produce some proof from a RTA that you are balanced on 30 frequencies without a processor.

Give me names and model numbers of XO's, preamps and line drivers or any other respectable signal controlling device that you have personally added to a system and found out it just ruined the whole thing.(Bass Enhancers not included)

Truth is, you have no footwork here to refer to in the matter. Have you been studying the concept for years taking opinions and suggestions on the issue?

I dont know where you go to listen to systems competing to be the best. Next time you are there, take a count of how many people there are controlling their signal.

Next time you want to play judge about my theories, you had better knock it over with a little bit of proof! You may disagree, but give a reason. I am not here to state just my opinion, I either know or at least have reason to believe what I say.

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There is more to SQ than being "balanced on 30 frequencies." What people are telling you is things like line drivers and EQ and DSP and "pre amps" can and will add noise to your signal and degrade the quality significantly. This is a fact,. If you use high quality gear, you can and should EQ for SQ comp, but it isn't going to be clean with most commercial gear and certainly not with the "$100" level gear you are advocating. Adding processors for the sake of having one is a bad idea and will likely lead to crap sound.

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ianarian is worried about being "balanced on 30 frequencies" however he quotes lines such as "I hate RTA's! A device that has no business taking readings in a vehicle! (4/24/09)

A ruler flat responce is not an automatic win. IMO a rule flat sounds sterile and lifeless. Processing, be it x-overs, equalizers, etc all leave artifacts on the signal. The more processing causes delays, phase shifts and interaction changes.

"Best of the best systems do not happen with a deck-amp-speaker "club trio" configuration."
Many issues are delt with by a competent installer without the "bandaids " you use as a life line. HOW?

Physical driver placement. Correct placement and mounting to eliminatate delays and off axis equalization. This is where imaging comes into play.

Passive X-overs. Impedance and frequency abnormalities can be treated at the driver, not applied globally. Passives change little over time leading to a consistant sound. If one needs an abundant amount of componets here, chances are the drivers don't mate.

Select drivers. Sometimes mixed and matched, sometimes matched off the shelf sets. The components are selected for off axis responce, frequency range and how well they play with others. This is an art within itself. Is a three way better than a two way? Not always.

Decks with say 1V can drive an amp with a 1V setting to full power. The commonly held conception that if it sounds louder it much sound better. This is where a competent installer is matching the speaker requirement with the amp capability.

"Truth is, you have no footwork here to refer to in the matter. Have you been studying the concept for years taking opinions and suggestions on the issue?".

Yes I have. I have 25 years experience in autosound (hobby, former business owner, installer), I make my living as a Live Sound and Recording engineer. 20 year member of AES.
I hold degree in Music Engineering Technology from U of M. Any questions Clear-Com boy?

"Next time you want to play judge about my theories, you had better knock it over with a little bit of proof! You may disagree, but give a reason. I am not here to state just my opinion, I either know or at least have reason to believe what I say."

Your speculations, you believe to be fact, are unfounded to established principles or experience. Reading your former posts this is quit evident.. You are on a forum with professional and educated contributers. Info you are providing to others is full of holes and ill concieved concepts. Autosound isn't rocket science but there are ridgid ideas in which advise is formed. Speculation is fine, but passing it off as fact is something very different.

Copacetic....

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ianarian wrote:

Copacetic....

So does that mean you understand? The point here is to help educate folks like yourself who have some wrong headed ideas about audio. It's installers who know their stuff like audiocableguy who you should be listening to and learning from, not wasting time arguing with.

Let me know if you are copacetic with the idea that you should hang out here and read as much as you can and learn how to be a better installer, or if you'd rather keep repeating your opinions as facts. Thanks.

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You will be the world's best installer when you realize you can never be the world's best installer.
You become an installer when you know what wires go where. . .

You become a technician when you learn and understand the principles of WHY those wires go there.

You become a professional when you understand and apply your knowledge.

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Now, Now--dont start the victory dance just yet! Remain seated gentlemen we are just about through here. At least, the badgering from my side. ..please and TY.

Copacetic- I was just trying to sound smart.

The RTA is a tie breaker, sometimes reserved for only that purpose, unless the competitions are organized otherwise, correct?

Yaaaa,   I once described in a post how I had sound that was immaculate.(Noted by SQ judge). But realtime results showed peaks or something that we couldnt recognize audibly. IASCA determined the machine is the ultimate judge, just as a tie(or close) in SPL warrants another pass.   It becomes a numbers game.

I had a hand in 6 different SQ project vehicles.   We've tried firing all shapes, styles and sizes of drivers from every which way, twice on Sunday, yadda yadda..... driver and tweeter location changes caused spikes and dips to play musical chairs on different bands. Perfection requires tuning, similar to any musical instrument.

Seems that every time I visit a shop that chooses not to stock or promote these types of devices, when I bring up this topic, -the typical response is: "Why do you think you need one?". My reply is simple: "Control"!

Whatever noise you believe is being increased, its not as relevant when your talking about a signal that is being changed to accommodate for that increase. The unwanted noise caused by the source to begin with, is decreased when strength(E) to the signal level is applied. Results include, but are not limited to: less gain required from the amp.   So now we have reduced background noise in a stronger signal, and the amp is using less gain to amplify the our cleaner signal. Yaaaa?

Increases in S/N ratio's, damping factor's and power supply module's are effort's to decrease the unwanted noise or distortion that the source itself is the most responsible for creating...

Lets pretend here for a second, that the signal controllers are really not worthy...
Take a look at reviews on something like the Clarion 3-way XO. You will see a lot of people who are convinced beyond a doubt that their sound is better. Idiots? All of them, us?

Never do I mention this sight name in reference. I refer to the opinions from this forum's members as "certain friends".

The other side of this debate consists of acoustic engineer's, SQ judges and individuals who have been around forever.(Like yourselves) They think that the source signal level comes with its own set of issues that need curing...

There is a big difference between a El.XO @ 120Hz, and the supposed setting that the amp is indicating at the same Hz. The filters were obviously added for convenience purposes.... Not as the recommended method to improve sound by excluding the external signal controller.

I have been dragging this through the dirt(to your dismay) since I first found this site!

If you guys mention to me that the setup of signal controllers is not good on the business end of things.   Setup takes too long, or people cant be trusted with the control. Then it will all make sense.

Furthermore-I make a judgement about who is asking, what type of questions. I believe it was Manootu? Who had the question... This dude should take my advice about what to do here. Not everyone has the means or even a remote possibility to obtain and install the type of equipment or practices that are so famously preached.

CLICHe' ----

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"Whatever noise you believe is being increased, its not as relevant when your talking about a signal that is being changed to accommodate for that increase. The unwanted noise caused by the source to begin with, is decreased when strength(E) to the signal level is applied."

False. A Gain Stage takes what ever the signal is, including noise, and increases it. Hense the word GAIN. Each gain stage, more processors, boost signal + noise in each step. Phase shifts are also issues. What do you expect for $100?

Increases in S/N ratio's, damping factor's and power supply module's are effort's to decrease the unwanted noise or distortion that the source itself is the most responsible for creating..."

Wow, never heard damping factor used in a line level converstion. mmmm Do you even understand damping?

"If you guys mention to me that the setup of signal controllers is not good on the business end of things." They are not good because the true problems aren't being looked at. Again I use the term bandaid.

"Not everyone has the means or even a remote possibility to obtain and install the type of equipment or practices that are so famously preached." Funny because they correct practices save money by not buying all the crap recommend by people who don't know what their talking about. The practices here are proven, basic install practices. Installer 101 stuff.

"This dude should take my advice about what to do here."

False. Your advise did nothing to answer his question in the first place.

"Bottom line: Be careful who you listen to and what you believe (good advice for life too). There are plenty of folks inside and outside the car audio realm that will simply make something up if they don't know the answer (don't want to look stupid). Then there are those that have been told a lie, accepted it as truth, and passed it along. When in doubt, get a second opinion."

caraudiobook.com
Author not credited.

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sorry for not posting in a while but had financial problems. got the jetta for sale so i took out the system and installed it in my truck.

ive found that the previous installer put an inline fuse of 100 amps at battery then a distro block with 20 amps less than the combined amps on both the sonys im using. the distro had 2x30amps=total of 60amps and both amps used 120amps. dont know if that made a difference but i removed that block and it pounds now. the jetta was a lot smaller and the truck is a lot bigger so i dont know which way the sound would go. but it definitely hits harder.

on another note, im going def and the only way to rememdy this is with more watts :D

somethings just tend to hit better in a more open vehicle.

on a side note, reading this thread almost made my head explode.

when it comes down to deciding if you need any kind of line driver its important to know what they are really used for. they are not magical devices that just make things louder, they really are intended to be used in situations where your RCA voltage falls below acceptable levels to be used by your amp and there are only two situations that i can think of 1) having a whole bunch of amps sharing the same signal or 2) having your amp a very long distance away from the source. voltage naturally decreases over distance.

in theory, the best system IS just a source, an amp, and speakers. proper installation and quality equipment will make up for all but the smallest imperfections. but, this is the real world, and we need devices like EQ's because no single speaker comes with a perfect response and a car's interior is full of sound absorbing and reflecting material. and i say it all the time, an equalizer is only worth having if you know how to use it like is is meant to be used.

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