ohms etc

[j0nny]

right ive looked into this a bit but this is one thing i can not get my head around, ive installed audio for over a year now doing literally anything, but one thing i can not figure out is the significance of ohm rating and the concept of bridging of running in series and how that can change it, just wondering if anyone knows of a good guide so i can have fun readin cheers

 

[T14086]

http://www.rocketroberts.com/techart/spkr.htm

 

[j0nny]

brilliant
enjoyed that, defnitly adding to the favourites
one thing that it doesnt mention tho if the ability to change ohms from an amplifier
im guessin its as simple as connecting two outputs of equal ohm output and it will be halfed?

 

[Donut Boi]

http://www.bcae1.com/spkrmlti.htm

that might help you some1 posted it on here b4 cant rember hu thow


Hope This Helps Tom

 

[volxstu]

brilliant
enjoyed that, defnitly adding to the favourites
one thing that it doesnt mention tho if the ability to change ohms from an amplifier
im guessin its as simple as connecting two outputs of equal ohm output and it will be halfed?

You cant change the Ohm's from the Amplifier as this is a measurement of resistance and resistance comes from the thing that you are trying to run i.e the subs. So if you add a 4ohm sub to another 4ohm sub you are reducing the resistance by half but they need to be connected together.

 

[volxstu]

By bridging the channels of an amp you are simply connecting to channels together to give you double the power it is as simple as that.

 

[chaos]

By bridging the channels of an amp you are simply connecting to channels together to give you double the power it is as simple as that.

And raising the impedance that manufacturers recommend the speakers show the amp, e.g. if the 2 separate channels can go down to a 2 ohm load each in stereo mode, then bridged they are generally recommended to have a load of no lower than 4 ohm.

Remember, the speakers cause the impedance shown to an amp. It's just a question of whether the amp is designed to take that impedance safely.

 

[Donut Boi]

And raising the impedance that manufacturers recommend the speakers show the amp, e.g. if the 2 separate channels can go down to a 2 ohm load each in stereo mode, then bridged they are generally recommended to have a load of no lower than 4 ohm.

Remember, the speakers cause the impedance shown to an amp. It's just a question of whether the amp is designed to take that impedance safely.

yep thats right but there's nufin saying you cant go past that lmao

im running my amp briged @ 2ohm and its sound and its not even ment to go down to 2ohm let alone 2ohm briged lmao

Tom

 

[j0nny]

rite i think ive sorta got this now

ohms = impedance = resistance?

though one thing from your comments confuses me, how do the speakers cause the inpedance on the amp? so you buy a speaker and then get the amp to suit the impedance of the speaker presumably

so eg: i buy a 12" sub (dual voice coil, 2ohm) then i would be looking for an amp than is either a 4 ohm 2 channel amp and bridge them or a single channel 2 ohm amp

from wat i gather ohm is just the restrictive side of speakers much like wire gauges to a sound system so a speaker has to be fed enough to power properly?

 

[Donut Boi]

ok this may help

You have a dual voice coil sub 2000watt and a 2ch 1000watt amp each voice coil is 4ohm and the amp is stable 2ohm briged so i bride the amp and wire the + from the amp to both voice coils + and the same with the - this give me a load of 2ohm also incresing the power output of the amp to 2000watt

you have a dual voice coil sub 2000watt and a 2ch 1000watt amp as before each voice coil is 4ohm BUT the amp is not stabe briged with a load of 2ohm so i need to wire each voice coil to a channel + to +, - to - this gives me 500watt per channel and a total output of 1000watts with both channels having a 4ohm load

you have 2 dual voice coil subs 2000watt and a 2ch 1000watt amp as before each voice coil is 4ohm BUT the amp is not stabe briged with a load of 2ohm as before BUT is stabe 2ohm on each channel. so from channel 1 i wire + to + on both voice coils of the 1st sub and same with neg. i the wire the 2nd channel + to + on both voice coils on the 2nd sub and same with the -. this gives me a total output of nealy 2000watts (lowering the inderpendence by half normally dubles the power output) so im getting 1000watts from ch1 and ch2


Hope This Helps Tom

Sorry My Spellings Not Very Good And Im Dislextic

 

[Renegade_8]

In theory the dynamic load of the cone affects the impedance seen by the amp, in practice if you put a DVM across the speaker coil with nothing else attached it will measure pretty much the impedance the amp sees. So its just the resistance of the copper wire in the drive coil. Its an impedance not a resistance because being inductive I lags v a bit.We have had bridging threads before, as the ends are driven in antiphase a "virtual earth" appears 1/2 way along the winding and each amp sees 1/2 the coil to ground. The optimum for power transfer is that the output of the amp has the conjugate impedance to the speaker (or it should be the same but capacitive I leads v.) In practice you can usually neglect the imaginary and just woprk with the number in ohms as if they were resistors.You can go lot lower in speaker ohms before blowing the amp up and depending on its design you may be able to run it permantley into a short , but you will be wasting a lot of power in the amp impedance, not hearing it out of the speaker.

 

[volxstu]

yep thats right but there's nufin saying you cant go past that lmao

im running my amp briged @ 2ohm and its sound and its not even ment to go down to 2ohm let alone 2ohm briged lmao

Tom

Well give it a couple of months and youll be wondering why your amp keeps clipping im sure that i cant be the only one who can say been there done that got the receipts of blown equipment to prove it.

 

[Donut Boi]

Well give it a couple of months and youll be wondering why your amp keeps clipping im sure that i cant be the only one who can say been there done that got the receipts of blown equipment to prove it.

Been going 6months and still strong and as good as new


Tom