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I have a tsunami db1100d that was running two 15" comp vr's. It was loud, but i don't know if my amp was putting out 1100 watts. 1 ohm btw. So my gorund bolt came loose and my amp fried. i can send it to kbaudio and fix it for $117 plus shipping with a 6 month warrenty or i could spend $80 dollars more and get a audiobahn a2200hcq, 1600 rms at 1 ohm. the thing holding me back is i already have a tsunami db4400 for my highs, so i have a matching pair. i said i would never o audiobahn but i think it is a nice amp. the only thing i dont know if if the audiobahn has a subsonic filter or not? i am running sealed now but might ant to go ported later. also, what would be the current draw on the audiobahn compared to the tsunami?
help me decide.

Thanks,
Chris

 
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If you're running at 12 volts (car in ACC), your current draw would be about 133 Amps..
if you're running with the car on at 14.4 volts, your current draw would about 111 amps

 
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youve got 15's, so I wouldnt worry about a sub sonic filter when shopping for a new amp.

but more importantly, are you absolutely positive your amp is what is blown? usually when ground wires come loose from amplifiers the radio goes or the RCA cables go.

you are sure the amp is dead?

 
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I am positive the amp is dead, the power supply if gone, 8 of the 12 voltage redulators melted, aka mosfets. I believe they are the ifr640's. I had it grounded with a ring terminal and a nut and bolt to the metal panel in the side of the trunk, I guess the bolt rattled loose, so the ground was not making good contact at all, i was playing my subs for someone full volume and the amp cut off, so i was like wtf, turn the volume downa and it cut back on, turned it back up like a da and smoke. My fault for not checking stuff when it went into protect but it is blown. If i sold this amp blown on sd or here, how much would you ask for it?

Darklegacy, how is current draw less at more voltage? are they inversely related.

Why would i not need a ssf with 15's? since we are on the topic of subs, would a box made for the subs facing up and a port facing the rear work well in our cars, i have a sedan.

But how is the audiobahn compared to the tsunami? will it put out it's rated power with our stock electrical. or will the electrical be fine until i get a yellow top or new 170a alt.?

Thanks for the help,
Chris

 
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Btw when i get this i will be running 0 gauge split to 4 gauge if it makes a difference in electrical, i will probably also do a ground from battery to chassis with 0 gauge.

 
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power output greatly simplified, is a function of voltage times current. so: P=IV, where P equals amplifier power in watts, I is current in amps, and V is voltage in volts. So the idea is that if your car runs at 14 volts, your amplifier needs less current to produce the same power. If it draws the same current, it will produce more power at a higher voltage.

A subsonic filter is designed to reduce damaging overexcursion at ultra low frequencies, or to prevent regular flow of a DC like current through the voice coils, allowing the coils to heat up through current flow without allowing them to cool through cone motion. lets say your subsonic filter is a 24 dB slope. more realistically, its an 18 dB slope, but we will use 24 dB anyways. if you set it to below your subwoofers useful range, say 20 Hz as a 15" comp VR, you are only getting a 24 dB drop in current by the time you hit 10 Hz. how often do you play 10 Hz throughyour subwoofers? I dont think its presumptuous of me to say never!

you could always extend up into the useful range of the woofer, say 30 or 35 Hz. might get a benefit now of functionality to the filter. Of course, now rather than merely just protecting the subwoofer, the filter is taking useable FR away from the driver! so in this second case, its actually decreasing the low frequency extension capabilities of the driver!

now, if you port the driver, we all know the driver unloads far below the tuning frequency. Its debatable exactly where for us mere enthusiasts, but its anywhere between an octave to half an octave below tuning frequency are the general argued points. so, if you tuned your box to 30 Hz, which is way high for a comp VR for musical purposes! yet half an octave down, for example, puts the driver unloading at about 22 Hz. put your SSF at 25 Hz with a 24 dB slope, and again you see ZERO benefit till you are well below 20 Hz! how much music do you listen to below 20 Hz? not too much I will be willing to bet!

now, if we are talking about 10" woofers, where they stop performing at 40 Hzish as a general rule, or porting such a woofer, where a tuning frequency might end up at 40 Hz or higher, weve got something to work with!

the one argument I can think of for a SSF usefulness would be if there is too much low end. if there is too much low end in a car, then a sub sonic filter to correct for cabin gain is basically a fix for a poor box design.

That is why I dont support sub sonic filters as a general rule. ever hear people syaing a cap is a bandaid for a hurting electrical system? whether or not that is true (I dont think its true, myself) we can use the same phrase here. a SSF is a bandaid for a poorly designed or built box for a 15 inch subwoofer designed for use in a car.

If you plan to upgrade your battery and alternator, your car stock will handle anything you throw at it in the short term for sure, whether it be the AB you are looking at, the tsunami you had, or two of each. definitely. lots of experience from a dozen members here with stock E-systems running more power.

as for which way to fire, from my own experience, I can tell you either all firing up or all firing to the rear both work darn well! but woofers up and ports to the rear, I am not quite so sure. is it imposible to face the drivers and ports the same direction?

 
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I thought that with a ported enclosure most sound comes from the port and not the sub itself so i assumed the port facing backwards with subs up would be the same as facing forward, i want the port backwards because of the gain in db's. I can fit a larger box with subs facing up more easily than facing back. My current box is sealed, 36" W 16" H 18" D. it fits perfect because it slides all the way back to the seats. So i need the the box 16" high so my only choice is the ports being vertical when subs face backwards because of the height, but the problem now is the width, between the trunk bars i think is 39.5", so 15" for each sub , 2.25" of mdf and that leaves taht leaves about 6.5" for the port width, while subs are directly against each other. it would be a tight fit, i have a time getting my box in and out of the trunk now so one deeper and a little wider would be tough. i would probably have to build two seperate boxes so they would fit, now there is more width taken by mdf. If you have any box plans that work well in a civic, please let me know.

On the issue of current, say the amp makes 1600 rms at 12 volts, not that it does just saying, say at 14.4 it makes 1900 rms, now even though it takes less amps to make the same power at higher current, since it is making more power, the amp would require the same or more amps at 14.4. Am i correct?

 
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all the port does is release the back wave of the woofer. the port tuning is how we ensure that backwave lines up with the front wave. thas why we say ported is up to 3 dB louder, its like doubling cone area. like a free doubling of woofers, if you will.

in your case, I would recommend upfiring everything. upfiring works really well in our cars. My ears are unable to tell which is louder, so even if you are a full dB down up firing, its still gonna be loud as all heck! I think youll love it.

I also think youll have phase problems upfiring the drivers and rearfiring the ports.

HOWEVER many SPL competitors run a box called the CRX box, mainly in CRX's and SUV's. that design, while admittedly is for the maximizing of a single frequency, works really well for hatchbacks at least, to get REALLY LOUD performance. so it MIGHT work.

check out the audio forums and ask how it performs musically. the way the design works is to have upfiring speakers, and the aeroports rearfiring at the very bottom of the panel in the back.

I still personally recommend ports and woofers on the same plane for music, but it COULD work, to do otherwise.

 
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in your example, the idea is that the same current is being drawn through the amplifier. lets say its a simple and ideal situation, that is to say, p=iv perfectly applies.

thus, 1600 watts at 12 volts means the amplifier draws 133 amps.

when an amp company says it makes more power at a higher voltage, they are saying their amplifier is "unregulated". in this case, it would be 14.4 x 133, or 1920 watts. pretty close!

this isnt exactly transferrable to real life, because we have voltage drops across wires, speaker loads are reative, rather than resistive, power is lost as heat everywhere along the path.

but thats the idea behind more power at a higher voltage. one reason companies choose to "regulate" their amplifiers, is that they dont loose power at low voltages. in our example, its not too inconcievable, especially in our cars, to be playing bass test tone music and have the voltage drop to a constant 11.2 volts through out the song. we hear loud loud bass and are absolutley loving it, but the reality of the situation is, the amp is only putting out 1490 watts at that voltage! if we had a fully regulated amp at 1600 watts, we only get 1600 rms at 14 volts, but it means we get 1600 at 11 volts, too.

so, for unregulated amplifiers, current is theoretically about the same. for regulated amplifiers, current flow has to increase or amplifier will change efficiency to increase used CURRENT flow to achieve the same power to compensate for a lower voltage. or in your case, when voltage bumps up to 14.4, current flow will decrease.

 
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I believe that i will try to make an enclosure to fit all on one plane because i don't want to try any design that has not been proven to work in our cars. so a visual example of how the port works would be that the rear of the cone is moved to the port to create another sub cone area, thus doubling cone area? i believe the audiobahn is unregulated. but aren't most amps unregulated or not fully regulated because most ratings increase with voltage? if you know of any fully regulated amps, please tell me what they are. And my example of 1200 at 12v 1900 at 14.4, was just a damn good guess. How much louder would my two 15's be from going from about 3.0 each sealed to 3.0 each ported. would the difference going to ported with 15's be more than with 10's or 12's because of more cone area? on the topic of current draw, the fuses on this amp add up to 120a, 4 30a. so if it draws 133 amps at 12volts and 111 at 14.4, how can it run with the car off at 12, but they amp doesn't quite do 1600 at 12 so it would probably be right around 120? but those are estimates and the amp could be more or less efficient. so if these estimates are close then it would be safe to say i would get at least 1400-1500 watts from this amp? so this amp takes around 120 amps and my tsunami 4 channel takes around 60 amps, so a max of 180 amp current draw on a stock 70-80 amp. alt. and a stock batt. don't sound too good. is it possible to get our alternator rewound for higher amps, if so how much higher can it be wound to? I really appreciate all the help

 
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you are totally right, most amplifiers are not fully regulated! thus the changing power outputs. JL makes a fully regulated amplifier, and JBL is beginning to as they release new crown amplifiers. those are the only two that come to mind, as far as fully regulate amplifiers go. naturally there are others, but my product knowledge is far from complete, so thats about the best I can do.

as for your box, thats a very good question! ever hear that rebuilding your box from sealed to ported can give you up to a 3 dB gain? the key words there are *up to* !

so, from before, we know that porting merely makes the enclosure more efficient in that it releases the back wave of the woofer. if youve ever read any posts in here about enhancing midbass in door speaker installs, members here recommend sealing off the backwave as best we can! so whats the deal here?

so, it turns out that, just like any other speaker, that back wave is 180 degrees out of phase with the front wave, and really degrades system response quite a bit! ... So, in another or hte same post, I believe I mentioned something about port tune. port tuning is how we reallign those waves, such that the back wave is 0 degrees fully in phase with the front. Now, the catch here is, that NOTHING we do for a ported box will make ALL of the wave fully allign! you may have noticed that when people discuss ported box specifications, they describe a volume and a tuning frequency. Thus, a 2 cube box tuned to 35 Hz is designed to allign the waves at around 35 Hz.

Now, there are two things to keep in mind. First, that the point of max gain wont neccesarily be 35 Hz (its gonna be darn close though!). And second, that this is your ONLY point you might get your 3 dB gain! For its still not guaranteed youll get your FULL 3dB gain at this point! from this frequency below or up, you get diminishing gains, as the waves become more and more disalligned.

So when everyone here says ported boxes are way louder, its technically true, but only a smaller passband of frequencies are really louder. Ported boxes CAN be built with Sound Quality in mind, and have. often. but its an uphill battle, compensating for changes in the waveform. a few competitors run sealed simply because they dont care to put in the work to make it perform! (you should ask to see the hypocrite's crossover design for the front stage....)

anyways, thats how the CRX boxes work, more or less for any car. the design of the CRX box is to get that peak frequency, then make it as loud as humanly possible. the peak in the car will be different than the box peak, because firing the ports backwards changes what frequency is 0 degrees in phase with the front wave, if any, up front.

If you want a good indicator of YOUR OWN speaker performance in a ported box, you should go to www.linearteam.org and grab a program called winISD pro Alpha. it will model your response based on box parameters. its a NEAT tool you can use to help determine optimum box sizes and port tunings to suit your specific speakers in your specific application. if you do decide to play with this program, go grab it, play with it a bit, then come back here and start a new thread asking some details about how to taylor it to your specific needs, and a grip of forum members will help get you started getting your drivers in the database and getting the curves you need.

and man, you are thinking too hard about your current draw! you say your fuses add up to 120 amp draw. So, put a 150 amp fuse by the battery, and install everything with no regard for the E-system. If your lights dim, and they bug you, add a cap. if your lights dim and you dont care, dont add a cap! if, after a couple weeks or a month, or six months, you notice it takes an extra crank or two to get the motor started, might look at a Die Hard or Optima red top under the hood. this might help your dimming too, and if you have a cap at this time, disconnect it at first for a few weeks after replacing to see if things improve by themselves. only if you have SEVERE problems will you need a new or rewrapped alternator. I dont think you will ever have a problem with that one.

as for the numbers, its not worth thinking about!