EjBaL

Ok here's the deal, I have a rockford fosgate 360a2. Whenever setting it up, I was always under the impression that the "punch bass" **** was basically the gain, but upon further reading and such, I find out that each channel has its own gain. It says in my manual that "the gains are preset to match most headunits output voltage" or something like that, but here's the problem. Here in this pic you can see what I mean, not my amp but its a rockford and its the same idea ...

Now what Im confused about is this, my amp is an older style rockford and it came out probably before most headunits had anymore then 2v outputs, mine has 4 volt outputs, should I adjust these gains? Also... I was going to use this method to set my gain with a 100hz tone recorded at odb?
"Set head unit volume to 3/4 of maximum. Turn off all eqs/presets in the head unit.

DISCONNECT SPEAKERS

P = Power in watts
I = Current in amperes
R = Resistance in ohms (effectively the nominal impedance)
V = Potential in volts (Voltage)

Knowns:
Resistance (nominal impedance of your speakers)
Power (desired wattage)

Unknowns:
Voltage (we'll measure this)
Current

Formulas:
P = I*V (formula for power)
V = I*R (Ohm's law)

So after a little substitution to get Voltage in terms of simply power and resistance we get

V = square_root(P*R)

So, for example, say you have a 4 ohm load presented to a 150 watt amp.

V = square_root(150*4) = 24.5 volts

This means you should increase the gain until you read 24.5 volts AC on the speaker outputs of your amplifier.

As a source, use a sine wave recorded at 0db at a frequency within the range you intend to amplify. You can generate tones in cool edit or use a program such as NCH tone generator. (credit for NCH to imtfox, IIRC and to Wysi Wyg)"

Here is my question, how am I going to measure my volts on the amp because I have the amp bridged, which means that I am using both channels, and each channel has its own gain, so how would I set each gain, dont I want to measure combined voltage of each channel since it is bridged? Im just confused. Also, someone who is good at this stuff, can you help me with this equation. Ok I have a 4 ohm load presented to a 450 watt amp (thats what my manual says my amp does bridged, 450x1. How do I figure that out? If I set the voltage to match that, wont that mean that my speaker which is rated at 300rms will be getting 450 and that is too much? I hope you guys understand what Im trying to say here...Im just confused as hell and need a little guidance. Also how do I match it with the voltage output on my headunit? I have a multimeter right here, is some could also tell me what setting on it I should use to measure with. Thanks ALOT guys. By the way Im powering a 12" Alpine Type R with it, dual 2 ohm voice coils wired to 4 ohms.

Saigon_Bob

iTrader: (2)

dude there was a pretty good discussion about this b4 teh boards went down....

you cant set them like that becasue the speakers arent a set resistance.. they have impedance which changes at certain points.

they best way to set them i think( with out the manufacture listing of the volts to look for) would be to set each gain the same as the other or you will kill you speaker very fast. and when you set them do it by ear.

when you hear distortion turn the gains down a little. also set the H/U at 3/4 volume that you listen to, not the total volume because unless you listemn to the head unit at full volumes you wont have very good bass at lower listening levels.

i.e: HU goes to 40 and you listen to it at no more than 30 then you should set the vol at 3/4 of 30

EjBaL

I see what you mean, so headunit goes to 50, max I usually listen to is like 35, so set the volume like 30? Its going to be a pain to get each gain exactly alike though because its bridged so Im not using both channels individually. If I were to do it by test the voltage, would I measure at the + and - that it is bridged to? How would I adjust the gain though is the confusing part, because basically I have 2 gains for I speaker, will the combined gain adjustment of the 2 give me the total voltage? Im just confused and wish that someone could describe it to me in simple terms, is there any way to measure the exact watts that the amp is putting out, so I can set it right around 300 to match it to the speakers specs? I know the amp can put out over 500 watts..

EjBaL

Ok I just got this off of rockfords site...but according to this I would turn the gains down all the way to match my 4volts from the headunit, but what I dont understand then is how do I adjust the power the amp is putting out? If I set it to match the headunit then sure its matched, but I always thought the gains were used to adjust so you didnt give too much power to the speaker, so how do I do that then? Is that what I shall use the punch bass **** for? Here is the article..
Correctly setting the Gain controls on your amplifier is easy if you have some signal test discs and an oscilloscope! But, if you don't happen to have those available, then you may have to do some common-sense guesswork to "dial-in" your amplifier.

The Gain control is NOT a volume control! The gain adjustment (or control) is a level-matching control that adjusts the amplifier to work with the electronic piece(s) used before the amplifier. This piece before the amplifier could be the head unit, an EQ, or a crossover, and you set the gain control on the amplifier to match that unit's pre-amp voltage level. You can find out the unit's preamp output level in the owner's manual for that unit, as most manufacturers know you need this information in order to set up your system.

Essentially, by dialing-in the gain control, you're telling the amp how much signal you're putting into it so the amplifier will reproduce the signal accurately. If you have the gain set too high, the amp will make full power right away, and you'll have problems with distortion and "clipping". If the gain is set too low, the amp may still make full power, but it might not sound as loud as it should, and you'll think you aren't getting much volume. Our amplifiers are capable of accepting a signal input level from 250 millivolts to 4Volts, and you change the sensitivity by adjusting the gain control clockwise (more sensitive for low-power decks like 1-Volt units) or counter-clockwise (less sensitive for high-powered decks like 4-Volt units).

Since we do not put "indicators" or markings on the side of the amp to indicate gain levels for specific input voltages, this is where you will have to do a little "educated guessing" to set the controls up correctly. An oscilloscope's signal-measuring capabilities would come in handy right about now, as you could read the output levels of the amplifier while playing test tones (like a 1KHz tone) to determine at what point your amplifier "clips", and that's where you stop turning up the gain control.

But, if you don't have any of this cool stuff, then you'll have to assume the gain control is like a progressive-gain dial that becomes more sensitive as you turn it up (clockwise). We usually tell people that if they have a 4-Volt head unit, turn the gain all the way down (counter-clockwise); if they have a 2-Volt head unit, turn the gain 1/3 of the way up (clockwise); if they have a 1-Volt head unit, turn the gain 2/3 of the way up; and for 500mV decks, turn the gain 3/4 of the way up. While these suggestions are buy no means 100% accurate, they will work fine most of the time. When in doubt, have a professional double-check your work.

As far as the Punch Bass control goes, setting it correctly is a matter of both personal preference and the type of enclosure you are using for your speakers. If you are using your amplifier with a speaker (or set of speakers) that are loaded into sealed enclosures, then generally we recommend setting your amplifier's Bass control no higher than 1/4 of the way up. If you are using a ported enclosure for your speaker(s), then we generally recommend setting the Bass control no higher then 3/4 of the way up. Because the Punch Bass control is really an equalizer, you should not use it if you already have an EQ hooked up to your system (unless your EQ does not cover frequencies below about 70Hz).

Saigon_Bob

iTrader: (2)

wow ebjal... im not gunna read that right now cuz im tired... but if you listen to it at 35 mostly set it to 26 or 25.... with the eq flat and no other enhancements on.

if both gains are going to the same speaker..( its DVC right.. so you have the whole speaker wired to both channels or one voice coil to each channel) then you should just set the gains by ear like i described b4 just set them both at the same time to the same place..

start with bass boost down and gains down, turn the gains up slowly till you hear distortion then turn them down a lil. this gives you a rough setting. then set you bass boost where you like it. adjust both gains and bass boost untill you hear no distortion and the bass is how you want it.

remember: car audio is subjective, so what sounds good to me may sound bad to you and visa versa.

the diff with doin the gains by measuring voltage output is that unless you have this specific voltage from the manufacture then you will be setting you gains "wrong" anyhows

read this website for some awsome info http://www.bcae1.com

i just read your last post.. thats pretty good info but if you adjust the gains really slowly( gains are pretty sensitive) you should be alright

EjBaL

according to that info I posted, if I set the gains all the way DOWN then it will be putting out maximum power and be matched up with my headunits output voltage, but then how do I adjust it in the "power" sense because my amp's maximum power is too much for the 12" Alpine Type R Im running. It is a dual 2 ohm voice coil sub, wired to 4 ohms, and from the terminal its just wired bridged to the amp, so its wires to the left + and the right -. Im just having trouble because I can play some songs with tons of bass and it will sound great and not distort at all, them some songs with not nearly as much bass it makes a sort of popping noise, sounds like the speaker is being pushed too hard. These gains are still set from the factory, because I didnt know that I was supposed to mess with them, I thought the punch bass **** was the gain.

Saigon_Bob

iTrader: (2)

they way the puynch bass **** is described it sounds like that is a remote *** bosst control. not a gain. like i said, im not telling you how you need to set teh amp but giving you an idea.. really whatever works for you is the best. although the pooping sound is prolly a ground problem i think

Saigon_Bob

iTrader: (2)

they way the puynch bass **** is described it sounds like that is a remote *** bosst control. not a gain. like i said, im not telling you how you need to set teh amp but giving you an idea.. really whatever works for you is the best. although the pooping sound is prolly a ground problem i think

EjBaL

no I mean the popping sound only happens with certain songs, and its when the bass hits, I can tell its the speaker not a ground, its strange because I can play like rap with tons of bass no trouble at all, them some songs with much less bass, sound like ***. I dont get it. The punch bass is a **** on it, its not a remote bass, just a type of bass boost I suppose..

Saigon_Bob

iTrader: (2)

yea remote bass boost ****( it plugs into the amp and lets you dontrol it from your seat)... why you subs bottom out on lower bass songs you got me.. you may be overpowering the subs of have teh xover frewuencey set at a bad freq, and teh subs are responding to sumthin they dont like.

if you havent read teh bcae1 website i really suggest you do.. it has more info than you or i could ever need. it dispells many myths too.

NEEDAZ

The punch bass **** is a remote "bass boost" gain setting. The amp has a stage that amplifies lower frequencies more then higher ones, the gain for this stage is set with the "punch bass" control. I forget the center frequency and Q off the top of my head, but it's just that simple. So you are changing the gain of the amp, at lower frequencies.

EjBaL

yeah I dont have it wired to a know or anything, its just a *** on the amp. Ive read pretty much all of that site, but alot of it is over my head and harder for me to understand. Do you guys have any good songs or frequencies that you recommend to use for setting the gain? I want to use something that has killer bass so I know if its set to handle that, then nothing Im going to play will hurt it. Any ideas?

NEEDAZ

Before you go though that, lets look deeper into this popping noise. This sounds like an odd-ball. But I have a thought. You said it’s on some songs/sounds and not others, right? Have you thought about the possibility of a bad driver? It’s not unheard of to have a bad speaker that is most noticeable at certain frequencies. This is most common when the voice coil separates. It’s hard it explain how things sound, but do you think it sounds like this is a possibility? Do you have a spare sub handy, or a friend that would let you try there sub?
The only other thing off the top of my head would be a ground problem. What HU are you running, make and model?
And as Bob said higher up, you CAN’T calculate an amps output power the way you listed above. If you go through some old posts I have a long explanation (if it’s not lost) why it won’t give you anything worth while. There was some debate back and forth, some good ideas and info back and forth.

Saigon_Bob

iTrader: (2)

If i may.... the discussion went on to the rail voltage of the amp which will determine a few things that im not well versed in) how clipping happens when you try to push past the rail voltage and the signal turns into a somewhat squarewave.


for tuning for killer bass id try a bass test cd, or Crunk Juice if you can i use that cd in my car to tune the bass

EjBaL

well, I dont think its a bad driver because its only like a month old, and I havent had any trouble with it at all. Its just like certain frequencies it doesnt seem to like...for example I can play big tymers or something and its fine, but when I played metallica outlaw torn or pink just like a pill, it sounded bad. My headunit is a JVC KD SH77...4 volt outputs, subwoofer control, all the good stuff.

Saigon_Bob

iTrader: (2)

could be the sub/ box combo....

NEEDAZ

The box is ware I was going to go next.
Is it sealed or ported?
Pre-make or did you build it.
It’s so hard track down these “sound” over the web. It could be a air leak if it’s sealed. It could be port noise if it’s ported. It could be box rattle if there is a loose screw somewhere. Can you nail down a song/part of a song that will make this noise every time?

The KD-SH77 isn’t know for ground problems, not like some other JVC models, so I don’t think the problem is there.

EjBaL

the box was made by my brother, its sealed, 1.0cubic feet exactly like alpine recommends, countersunk screw holes, wood glue on the seams and liquid nail on the inside, weather stripping around the sub, 3/4" mdf particle board...trust me the box is perfect, and there is NO air getting out at all. like I said it just seems to not like certain songs, and i have to turn the woofer level down on the headunit, or else it sounds bad. Maybe its just me? I dont think it is though...

Saigon_Bob

iTrader: (2)

i know that with my box.. the sub has way less airspace than it was designed for. its like .8 when the minimum is 1cuft on some songs where the bass is particularly punchy i hear a sound like popping but its the subs "reverbing" or kinda like distorting a lil from too few airspace and too much tight push

NEEDAZ

Got me at this point, with out hearing it I’m outa idies. But it don’t sound right.

EjBaL

the air space is perfect for it, it almost just sounds like the sub is being pushed too hard, or having too much excursion, but the reason I dont get it is because it happens with usually the songs with less bass. Whats a good tone to set the gain with, Ive heard from 100hz to 50 hz, but whats a good all around tone? Do I want one recorded at 0db? Also... any good sites or place I can download tones? Thanks guys.

Saigon_Bob

iTrader: (2)

unless you drive around listening to test tones... id set it using your favorite music cd

ScrapMaker

I've heard many setups where people have the box the "exact" specifications as the manufacturer recommends... the woofers almost always sound better in larger boxes IMO... if you have the space.

and pretty much gain IS volume control... you are matching the VOLUME of your amplifier to the volume of your headunit

if you had a good headunit this could be adjusted from the deck... I leave my amp's gain on 0db because its too much work to get them exact, and if I have them off at all, the subs will start to cancel each other and wear one out... so I do all the control from the h/u.

is your box single or dual chamber? you can easily tell by pushing on one woofer and see if the other moves too... if so, do NOT hook these up in stereo, if you are... mono only, unless you want to have crap sound and wear out your woofers.... even people with dual chambers still usually run them in mono.

the remote bass **** seems like a waste, most good amps come with real remote gain ****... which I can see being helpful.

what that website was saying is that with a higher h/u voltage output, the amp will be louder at the same "volume" setting on the amp... your 35/50, if you will. If your subs play loud enough at 0db, then that's what you should do, otherwise you are in for a real treat trying to raise both gains equally.