Ohms

[BRUN]

after lookin at the 12" Alpine subs.........there dual voice coil......however they do 2 versions

2ohm + 2ohm or.........4ohm + 4ohm

i havent got a clue what the difference is, anyone explain ?

 

[Evil ICE]

Its the way you match subs up to an amp to get the most power out of it. Essentially it is just a case of doubling and halving numbers.

For instance if you have a dual 2ohm sub you can either wire it in parallel to give 1ohm or series to give 4ohms

If you have a dual 4ohm sub you can wire it in parallel to give 2 ohms or in series to give 8ohms.

Did you decide on what amp you are going for. If you can let me know I will tell you which sub you need to go for. Also if you are going for more than 1 sub..that changes things too.

Russ

 

[BRUN]

ive decided just the one sub, probably 12" now, definitely Alpine Type R

the amp ill be getting is the MRV-F450 5channel amp

is it..............if my amp is 1ohm stable then get the 2ohm version

however if its 2ohm stable then get the 4ohm version

and if its only 4ohm stable then get the 2ohm version but wire in series ?

 

[Evil ICE]

Thats basically correct what you said there.

 

[Frosty]

Remember the ohms are measuring speaker impendance - not resistance.

It basically means that the higher the impendance, the tighter it will sound. Impendance defines how easily the speaker will stop moving. Low impendance means the speaker will cary on moving a little after it has been told to stop - this creates hangover, which doesnt sound too good.

Higher impendance stops the speaker very quickly - resulting in a really clean and accurate sound.

I hope this is of some use to you.

 

[BRUN]

so why is it then that most expensive amps are advertised as 1 ohm stable ?

surely if its better to higher impedance then wouldnt they advertise like 8ohm stable ?

 

[Evil ICE]

If you ever go to a soundoff competition. The SPL bass nutters will usually run their amps at 10hm or lower if possible to get the most power that they can. If you see a competition SQ car you will notice that the amps will run down to 4ohms or 2ohms minimum. You will never see an SQ car with amps at 1 ohm as the quality suffers. Either way at the extreme ends of the scale the amps are expensive.

Russ

 

[BRUN]

so what should i go for then ?

will my amp be able to cope with 8ohms then ?

 

[Evil ICE]

every car amp will be able to cope with 8ohms. The problem is that you would never run it at 8ohms asmost amps are designed to put out the most power at either 2ohms stereo or 4ohms bridged (except for the class Ds)

I know youre thinking of going for the Alpine 5 channel amp so you obviously want to go for quality rather than large amounts of bass. Most 5 and 6 channel amps dont have very high powered sub output which is why you dont see them in installs very often. You also need to think about resale oportunities in the future as you will sell 2 class A/B or a Class D amp much easier than a 5 channel amp as there are only a select few that use them. You are also limited if you want to add another sub at a later date.

I personally would look at using a 4 channel class A/B amp with either a 2 channel class A/B or a class D amp powering the sub. Thats if the buget will allow of course.

Russ

 

[BRUN]

not sure if my budget will stretch to that mate, and i know it might seem quite underpowered to you, but for me it will be totally fine, i want sound quality over bass, however i do want bass, but im sure the 12" sub on that amp would be more than enough for me

the amp can still do 200W RMS for the sub cant it ?.......thats definitely enough for me mate

so.............how should i wire my sub ?

 

[Evil ICE]

The amp will do around the 200 mark yes which as you say will be enough for most people...Its just that im a bit mad and dont know the meaningof the word overpowering.

If you get the amp youre thinking of, I think it does its best powerat 4ohms bridged (correct me if im wrong). In which case you will need to go for the dual 2ohm sub and wire it in series.

Russ

 

[BRUN]

its a 5 channel though mate ?.......the sub channel is seperate an doesnt need bridgin ?

 

[Evil ICE]

Sorry..slip of the tongue there. Is the sub channel 2 ohm stable on that amp or does it only do 4ohm as that would dramatically effet which sub you get.

Russ

 

[BRUN]

i think it is 2ohm stable yes, in fact i think the 200W RMS is at 2ohms....

 

[Evil ICE]

Ok.You need to go for the dual 4ohm sub instead then. Wire it in parallel and youll show the amp a 2ohm load.

 

[BRUN]

will the other speakers be affected by this ?

what i mean is i would have to wire them up differently wouldnt i to get them to be at 2ohm aswell ?

 

[Evil ICE]

You wont be able to get your speakers to run 2ohm unless you run 2 speakers off each channel as near enough all of them are 4ohm.

Russ

 

[BRUN]

so would going for 4ohm load give me better sound quality, but a 2ohm load would give me better bass ?

would it not be best to run it at 4ohm because thats what all the other speakers will be at, would it not be out of balance in any way, sorry if im talkin b****cks

 

[Evil ICE]

sorry mate..your talking b****cks..only joking!!!

Wire the sub to 2ohm operation and youll get more bass. If thats what the amp will do then thats what it was designed for.

Russ