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One amp per sub or one amp for both?

B

Blazer79

1/2 ton status
Joined
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I have two subwoofers:

Rockford Fosgate Punch XLC 10"
4ohm
200rms
400 peak

JBL GT 10"
4ohm
250RMS
400 peak

I also have two identical Profile Baja amps, each one pumps 150rms (300 peak) per channel or 300rms bridged (600 peak).

Should I install one bridged amp for each sub or should I leave the amp stereo using one sub on each channel? What are the pros and cons on each setting?

I'm asking this because if I can get away using only one amp, I can probably use the other one on my daily driver Toyota truck.

Thanks for your advice.

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well if you use one amp you are pumping 150rms per speaker which will deffinetely be enough to sound good. however you wont be using the full potential of the speakers.
if you use one amp per speaker you will be pumping a mean 300rms per speaker. speaker 1 is only rated to have 200 and speaker 2 only 250 so you run the risk of blowing them. rms is the power that is constantly going to the speakers, not just on big hits and what have you. if you go one per speaker, it will deffinetely be louder but i would turn the gain down a bit so they dont recieve as much power. if it were me and i had another car, i would use one amp in each car. one will be plenty to bump those speakers. if you have any custom enclosures or any way that you think is really good for the subs, send me a description or pics of your design if you would. thanks
 
I think you're overlooking your main problem. Don't use 2 different subs in the same car. Have you ever seen anyone do that in a pro install like what is in all the magazines? The reason people don't do that is because each type of sub has very unique characteristics. When you put the different types together, they will end up fighting each other instead of helping. Sure the SPL might gain a bit, but the sound quality will suffer.
And don't worry about giving a 200 RMS rated sub more power than that. It is easier to damage a sub with not enough power instead of too much. Without enough power, you'll see alot of distortion which is the main killer. As long as you set the gains correctly and don't get stupid with the volume, too much power is just fine. Right now my amps birth certificate says 998 watts, whereas my 2 subs are only rated to take 200 RMS watts a piece. Its been wired like that for over a year and the subs are fine.
So sell the JBL sub, get another Rockford and use 1 or 2 of the amps. Either way it should sound good.

'73 K5
Chevy good...Ford bad
 
I did build some custom enclosures. I will take pictures of them and post them when I'm finished with everything. I'm even planning on making more and selling these enclosures, since they are a perfect fit, volume, cu ft, and disguise.

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I never thought different models could make such a big difference, especially on subs (I know mids and highs do), which are going to be hidden all the way in the back of my Blazer. In fact, I thought their different sound characteristics would complement each other and make the bass more "complete". Is it really that much of a quality degrade?

I bought the JBL first, and I thought that was it, but as with horsepower, it's never enough. I especially felt the need for more bass when the top was off. So I got a pretty good deal on the RF and bought it.

Each sub will be placed on the very rear of the rear side panels, one on each side of the Blazer, facing each other. They are not going to share a box or anything. They are not in those solobaric boxes or stuff like that, each one has it's own sealed box. Do you still think they will fight each other?

Now on the magazine stuff, come on! That's an unfair comparison. I'm not a pro, nor trying to be one. I'm just trying to get some loud, nice-sounding, ass-kicking bass. Those guys are usually sponsored too, so no wonder why everything is only one brand.

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Well if you bridge your amp you will have max potnetial of it. As for two subs fighting each other, hopefully they are not aimed at each other. I have 4 subs in my vehicle in a very unique enclosure. Have photos on my website. They are running on one amp pushing 600 watts. BTW when you run alot of amps you need giganto power wire.

<font color=purple>79' K-5 396cid 600hp, TH350, NP203</font color=purple>
<A target="_blank" HREF=http://blueknight.coloradok5.com>http://blueknight.coloradok5.com</A>
 
Blue Knight, I remember you. Long time no see!! Glad to have you back.

On the subs, they will be aimed at each other one on each side of the rear of the Blazer. Does it help if I change the phase on one of them?

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Well heres what happens when you fire two woofers directly at each other. Each sound wave they produce cancel each other out. You will get sound but it will not be clear and loud. If you can angle them a bit off from each other. Yes im back. Been really ill and well just out of the limelight. look at my box on my website and see the woofer angles. You do not need much to gain alot of sound. I had only two the of the twelves firing acorss from each other and they were muddy, not punchy and couldnt get very loud before they started slapping(bottoming out) Designed this box um yes I added two more woofers but I did get 35db more sound out of the new configuration. Last recorded 153spl

<font color=purple>79' K-5 396cid 600hp, TH350, NP203</font color=purple>
<A target="_blank" HREF=http://blueknight.coloradok5.com>http://blueknight.coloradok5.com</A>
 
Blazer79: The different sounds of the different subs will not help each other. Think of it as you and a friend trying to push your Blazer. How do you get the most done? By both pushing at the exact same time...like 2 of the same subs. Different subs will move at different times. Also you can think of it like this: Would you put a 4 inch Skyjacker spring on the drivers side of your truck and a Rancho 4 inch spring on the other side? They're both 4 inch right? You know how different springs can be...subs are the same way.
There is just nothing to gain from it and if anything it will be detrimental to your sound. Thats why the pros never do it. And its not just the pros or magazine guys. I've never seen any shop recommmend doing that.
One more thing. Every sub has different needs in terms of air space it will require for the best possible sound. I doubt that the JBL sub will need the exact same size as the RF sub. Do you really want to go to the trouble of building 2 different sized boxes? And don't even get me started about the importance of the box. True story: I used to work with a guy with 2 really nice Oz 12's in a crappy premade box. I built a computer designed box for another guy with some really crappy Pyramid 12's and the Pyramids sounded better AND were louder. Box design is so important.
If you aren't concerned a ton with sound quality and just want some punch, use the different subs...it would just be better if they were the same. Hope this helped.

'73 K5
Chevy good...Ford bad
 
BlueKnight: There was a post a while back where a guy posted that he got "x" amount of horsepower out of an engine with not that many mods. Anyways a bunch of people said he was making it up and it got nasty.
I do not want to start anything like that, but let me get this straight. You added 2 more subs and changed your box design and gained 35 dB??? That is really hard for me to imagine. No more amps or anything? Was it measured with the same meter each time? Was it a dBA weighted measurement like the standard IASCA scores? Where was the mic at? I'm not trying to be a dick, I'm just curious. I've done SPL systems in K5's before so I know how tough 153 is to achieve in one.

'73 K5
Chevy good...Ford bad
 
Actually specially designed ports, a custom fabbed box for peak performance. The amps that I have werent straining so hard so they were not taxing the electrical system and the sub amp well it is bridged at over 600 watts just to the subs now. Some tweaking of how the speakers were wired and the firing surface prepped yes. 35db was the gain. SPLD at an audio competition with an audio control meter. The box also adjusted into a spl position for the competition. Come to find out positioning distance from firing surface made a bunch of difference. Also the woofers were not firing at each other. So 18 speakers and 3000 watts equals my score. That measurement was the highest it has ever scored. So it may be off by a db or two which is fine. There were alot od changes to the system but only two more woofers were added to the mix. that reminds me need to update my site with the new spl and changes

<font color=purple>79' K-5 396cid 600hp, TH350, NP203</font color=purple>
<A target="_blank" HREF=http://blueknight.coloradok5.com>http://blueknight.coloradok5.com</A>
 
Badass. Audiocontrol RTA's are about the nicest.

'73 K5
Chevy good...Ford bad
 
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