Amp Bridge
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=23473
Printed Date: April 27, 2024 at 2:58 PM
Topic: Amp Bridge
Posted By: raico
Subject: Amp Bridge
Date Posted: December 28, 2003 at 9:41 AM
hey guys im quite new to this scene but already quite enthusiastic and motivated. I bought a 2 channel (40w x 2) amp to power my sub. it isnt much but will have to do for the moment. The sub is a 200mm Sub (nothing special, 40w Rms, 150w max) and want to join the 2 channels on my amp to combine the power and have more blast for the sub. The amp has 4ohm's per channel. Could i just wire it all like a series circuit to bridge it? Also, when i tested the system it sounded a bit tinny i.e. there was treble comin through with the bass and it sounded crap mixed together not quite 100% subwoofer. I added a crossover but it didnt do much. I have 2 crossovers so could i add them to the whole ensemble? Also would it hold the 150W max of each of the crossovers? I know it might make the whole thing a bit complicated but im on a real tight budget at the mo. I would appreciate any help. Ive gotten from knowing nothing about car stereo to installing my own equipment thanks to reading these helpfull forums and install guides. Thanx!!!!
Replies:
Posted By: jakita
Date Posted: December 28, 2003 at 1:08 PM
Is your sub in an enclosure? Only use one crossover on a single channel. What Brand/Model equipment do you have? Do you own a multimeter? I can help you but I need this information.
Posted By: jeffchilcott
Date Posted: December 28, 2003 at 3:09 PM
is there a crossover on the amp at all or a lowpass/high pass switch? what are the name brands on this equipment and what is the sub enclosed in?
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2009 0-1000 Trunk WR 154.0DB 2009 1001+ Trunk WR
2007 USACI World Champion
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Posted By: raico
Date Posted: December 30, 2003 at 8:33 AM
phew, thanx for the reply. The sub is on infinate baffle mounted on my rear deck. it has a diameter of 200mm. The two crossovers are separate componetns to the amp, also no brand name.The crossoverers dont have any switches at all, no adjustments unfortunately, very basic. on the package it said something about 5,000Hz. Like i said, the amp is a cheap one with no brand name but is half decent. It has 2 different input types- high level and low level. It worked best on the low (RCA) as the outputs on the source unit were RCA. I can hook it all up no probs i just wanna bridge the amp to get more power. I have a multimeter aswell and figured out the basics how to use it. The other problem is that i can hear voice and treble n stuff from the sub and the one crossover didnt do much. Adding another to the single channel wont help then..
Posted By: Alien509
Date Posted: December 30, 2003 at 9:36 AM
connect both the + from each channel to the + terminal on the speaker, both - on the amp to the - terminal on the speaker. Usually crossovers have a little knob or screw or somthing to filter to a frequency, the lower the hertz the more bass and lesser treble.
Posted By: Alien509
Date Posted: December 30, 2003 at 9:38 AM
oh and make sure the crossover is hooked before the amp (IE.) The output from the head unit goes into the crossover then the output from the crossover goes to the amps input.
Posted By: raico
Date Posted: December 30, 2003 at 10:20 AM
cool, thanx alien509 The crossover solution sounds good as i was hooking it up the other way round. ie putting thecrossover between AMP output and the SUB. The wiring for the bridging you suggested, wouldnt that be parallel? would it also work in a series type circuit. Im saying this cos i think in the AMP manual it said something about dont connect the (-) terminals from both channels together. i might be wrong...
Posted By: jeffchilcott
Date Posted: December 30, 2003 at 12:31 PM
i was questioning something, if you crossover said 5000hz, your crossover frequency might be way to hihg. look at building your own crossover that goes right before the sub terminals, also look into building a box no name subs are not the type of sub to use for an infinate baffle
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2009 0-1000 Trunk WR 154.0DB 2009 1001+ Trunk WR
2007 USACI World Champion
2007 World Record
2006 USACI Finals 2nd Place
Posted By: hobbes6981
Date Posted: December 30, 2003 at 1:13 PM
I would suggest getting a low pass sub crossover. Is your sub a single voice coil? 4 ohm? Is your amp bridgeable? If so, you could bridge the amp down to one channel and still maintain the 4 ohm impedance. In the manual for the amp, it should tell you if its bridgeable and which terminal of each channel needs to be hooked up for bridged mode. Usually bridging increases the power by anywhere from 1.5x to 2x the sum of the two channels (rms). I would also suggest putting this sub into a small sealed enclosure. There are only a small percentage of subs able to run in an infinite baffle setup.
Posted By: Alien509
Date Posted: December 30, 2003 at 4:11 PM
The amp should be ok if you bridge it like I said.... and as for the crossover being that high that he mention, he probably only saw the highest frequency the crossover will filter to.
Posted By: jakita
Date Posted: December 30, 2003 at 8:00 PM
OMG have fun guys it looks you are having fun learning. You might not want to bridge the amp though unless it has directions to or says that it is two ohm stable. If not you might harm the amp and or sub not that they are anything special.
Posted By: Alien509
Date Posted: December 30, 2003 at 8:19 PM
I doubt his low powered single woofer produces a 2 ohm load <_< >_>
Posted By: jakita
Date Posted: December 30, 2003 at 9:02 PM
Yes Alien you are very correct. The point was not that the driver produced a two ohm load but the amp always sees less resistance when it is bridged. What I am saying is if you put a four ohm load on a bridged amp it sees a two ohm load. When a four ohm load is on a single channel it will see a four ohm load. This is why you must see if the amp is two ohm stable. If it is then you can either brige it with a four ohm load or you can put a two ohm load on each individual channel. I know it sounds wierd but I swear I am not making it up.
Posted By: raico
Date Posted: December 31, 2003 at 7:13 AM
thanx guys the manual for the amp is tiny. Thats why It doesnt say anything about it being bridgeable or Ohm stable but 4 ohm per channel. The only thing (i looked it up in the amp manual) is that it says "dont connect the (-) terminals of the 2 output channels together" (a parallel circuit, right?). So i wanna connect it in serial instead. would this be possible or is the manufacturer hinting that bridging is not a good idea? The whole setup is cheapo like i said. All im trying to do is tweak around with the crap ive got. I just cant buy anything else at the mo (im broke). ;-( thanx for the help
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