Welp. I finally got my 12" Brahma, after 28 days. GRIN I put it in a SubZero 1.2" cf enclosure and have it hooked up to a Hifonics Hercules Generation XI. The amp is "rated" at 1500 watts RMS by 1 ohm. Which may be a bit overrated. But I would assume it can hit close to 1k watts giving proper power supplies.
I wired the Brahma at 1 ohm. Ran it lightly for a little while, but then just couldn't wait to hear what it could do. I turned the volume up quite high and heard serious distortion (at first I thought I had seperated the spider from the cone).
So i took the Brahma out of the box to be relieved that it was fine. I would assume it is the amp, but the amp was no where near its max, because the sub was hardly hitting its max.
I only have a 65-85 amp alternator in my car. What i was able to deduce was that a lack of current (and ampage) was causing the amplifier to clip. Is this fair to say? Would an upgrade of my alternator (which i plan on doing anwyays) fix the problem? Or was I actually reaching the subs limits?
Thanks.
Derek
Replies (14)
ryan on 06/23/2003 22:38:13
This is what i got off there website. This is how much power u need in a sealed box to get the maximum out of this sub. Qtc Box Size (L) Box Size (ft3) Power
0.5 170.5 6.01 400W
0.577 59.8 2.1 500W
0.707 25.9 0.92 900W
0.8 17.6 0.62 1300W
0.9 12.6 0.45 2000W
1 9.6 0.34 2800W
So if ur box is sealed ur defientaly over powering these subs.
ryan on 06/23/2003 22:56:23
I can never get it to come out right when i reply but .5, .577, etc. are the Qtc whatever that means then 170.5, 59.8, etc. is box size in liters, 6.01, 2.1, etc. are the box size in ^3 and i think u know what the power rating is.
xplicitblitzboi on 06/24/2003 00:28:59
well i was gonna say something but i decided against it. i'll just say im not a big fan of brahmas even though a lot of people still swear by them. i dont really know what to tell ya other than to maybe try another amp. GRIN
good luck
BlitZ
Swez on 06/24/2003 00:36:16
The 12" Brahma sealed recommendations are 0.7 to 1.5 cubic feet per sub. So, if you have 1.2 cf, should be good to go there.
Are you sure you wired the voice coils up properly? Could the VC's be out of phase? Have a closer look...
Do you have a link to that amp? If you are any where close to 1kW of output power, your amp is starving for power with such a small ALT. That may well be the root of your problems here.
Swez
xplicitblitzboi on 06/24/2003 00:54:55
oh yeah, i didnt notice that in the original post. that alt is way too small for a 1k amp. you will definitly(sp?) need a new alt if you are planning on running your system properly and efficiently.
sorry to break it to ya, but thats not cheap. you might want to look into rebuilding your alt, i hear that thats not nearly as expensive as a brand new one.
sorry
-Blitz
ryan on 06/24/2003 01:02:36
But Swez right on adire site if u go to power handling it says for a 12" in a sealed box 2.1^3 with 500watts to it will push it to its limits and a .92^3 sealed box with 900 watts goin to it will push it to its limit. So wont 1.2^3 in a sealed box with at least 1000watts push the sub past its limit?
Swez on 06/24/2003 07:43:37
According to the Manual, the Brahma in sealed box of 1.0 cf will take ~1.3 kW (RMS) to reach X-max @ 20 Hz. In a 2.0 cf sealed, takes ~800 watts to reach X-max @ 20 Hz.
If we extrappolate a bit, 1000-1100 watts RMS will hit X-max @ 20 Hz in a 1.2 cf sealed box. However, most low end content is higher than 35 Hz... so it can take a bit more power to hit X-max above 20 Hz. WinISD can model this for you, if you plug in the T/S parameters and let the program do the rest.
Finally, need to allow a few days of "break in period" for a new sub. Just run it a few days at lower power before you throw the kilowatts to it.
Here is the link for Owners Manual: http://www.adireaudio.com/Files/BrahmaOwnersGuide.pdf
Swez
dflock on 06/24/2003 08:44:32
Sounds good. I am assuming it is more of an electrical problem than over doing the sub, but I may be wrong. My entire electrical system almost dies when the sub gets turned way up. I'll look into rebuilding the alternator, but my only problem there is I need a car to get to work.
I also need to break the sub in as well. I'll just give it some time and see where it goes. The sub sounds great even at low volumes, just not quite as loud as I thought it might get. But it maybe my amp / set up. Not to mention I haven't even hooked up my amp for my components, once that happens I won't have any electrical system!
Derek
Swez on 06/24/2003 21:59:33
Good chance your car electricals are pooping out, once the amp gets to a point of pulling ~75 amps or more, the whole system goes into power depeation mode. That's hard on the ALT/BAT and amp(s) too.
A short term step in the right direction, get yourself a larger CCA rated battery. Most stock BAT's are 450-650 CCA rated. In your case, go with the largest CCA rated battery you can fit under the hood, for more reserve current. WalMart carries Interstate brand and these are pretty good and low priced too.
You may want to consider a Deep Cycle battery for this application. These cost a bit more, but they can take many cycles of deep discharge/recharge cycles... no problem. A standard car starting battery will only take a few major discharges before you can kiss that battery good-bye.
Once you get that part squared away, then figure out what the largest amperage output ALT is availble for your car. Many better parts stores carry several output versions for most cars. Same form and fit, just a larger output capacity. In your case... 120A would be a good target to shoot for. Larger if you can find one. A quality rebuilt will cost much less than a new ALT. They usually have a lifetime warranty too.
Finally, consider upgrading the ALT/BAT and BAT/GND wire gages. Stock wires are usually #8/10 gage wire. Consider a #4 kit here for more current flow capacity. Not expensive either.... can get these pre-packed at a good autoparts store too. (Truck wire kits are large gage... just get the proper length)
Swez
PS If you have a 2nd amp planned for the future, be sure to use #2 gage main power feed line off the battery to a D-block. Then you can split #4 to sub amp and whatever to your other amp.
dflock on 06/25/2003 12:36:29
Swez,
Thanks for the info. Since my car is new, and under Subaru warranty I will have to contact my dealer and see what I will be able to do that doesn't start voiding out parts of my warranty. I do know that the Subaru Outback comes with a 135 amp alternator, I might be able to get that put in my WRX.
Do the amps of the alternator effect its size? My WRX has a pretty crammed front end. I guess I will have to talk with my dealership and see what options i have.
Hopefully I will be able to sqeak some more power out of the amp and sub after an upgrade. I just recently purchased 0/1 Guage power wire from KnuKonceptz.com. Man, that stuff is huge! And I also got a Fused Distrobution Block with an ANL 60 amp and an ANL 100 amp fuse for each distrobution of power. Even has a nifty Volt Meter built in, so I can check my stupid LA Cap in the trash.
One question. I didn't purchase a 1/0 guage fuse holder for the power wire. Should I? Or is having the fused distrobution block good enough? I would assume I need a fuse closer to the power source. But I am having trouble finding a AGU fuse bigger than 100 Amps. Should I just get an ANL Fuse Holder?
xplicitblitzboi on 06/25/2003 16:08:53
well, as far as the alternator goes, i think you wont have a problem since someone has found a way to fit 8 altys in an astro van. it may be a different size, but i dont know. i may have mentioned this earlier but they can recondition your current alternator to a higher amperage and it doesnt cost as much as buying a new one. just take it to an alternator place and see what they can do.
Blitz
Swez on 06/25/2003 20:24:43
Yes, there is a correlation between physical size of the case and output potential. Just like in car engines, if you want more HP, gotta have plenty of displacement to produce more Uhmph!
Rebuilding the present ALT can help... but you can only go so far in a small casing. Yes, larger diodes are possible, pulling the voltage regulator and installing a HD output version is also possible. But when it comes to the real guts, like the stator and field coils, may not have a whole bunch more room for a major upgrade in a small casing.
Good idea to check with your dealership and see what options are possible on this vehicle. It would be great if you can fit that 135A Outback ALT in there. May be a tight fit or a few mechanical mods needed, but that would help a lot!
About your fuses... YOU NEED A LARGE FUSE (100A) CLOSE TO THE BATTERY !!!. This protects the battery and electricals under the hood from a dead short. If the main power feed wire were to get damaged and shorted to ground between BAT and D-block, could have a fire. Gotta have it close to the battery!
Swez
dflock on 06/27/2003 08:55:21
Swez,
Again, thanks for the good information. I have a 100A AGU fuse, i will just have to go out and buy a 1/0 Guage Fuse Holder. Man, I just keep finding ways to spend more money! But I am putting a considerable investment into my stereo system so it is important to protect it as much as possible.
I am keeping my fingers crossed that the 135A Outback Alternator will fit nicely in my WRX. I haven't had a minute of free time to check with the dealership, but I will soon.
Unfortunetly I've run into even more installation issues. As I went to put my Koda 6.1 components into the front doors. I found that the custom spacers are too small. The Koda doesn't fit flush in the spacer as the upper frame and connectors are in the way! Ugh... I am working on thinning the inner circumfrence down and hoping that will do the trick. I am totally dying to hear this system. But as with all good things in life, wating is the hardest part.
Swez on 06/27/2003 13:44:55
Hehe, you say it well... waiting is the hardest part (that's part of a song by Tom Petty & the Heartbreakers) Gee, I have been waiting a long time for a few things on my "wish list" as well...
Waiting builds patience, patience builds character and character turns boys into men!
Good luck on fitting your Koda's into the spacers mentioned. Can the spacer be split into 2 equal halves (Clamshell type deal) and mount your Koda's that way? Or mabe a small knoch cutout in the spacer to accommodate the wiring terminals etc? Just make sure the wiring terminals do no contact bare metal on the door as this will cause a short to your amp.
Swez
Hang in there.... pocession is 9/10ths of the law! GRIN
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