# Resistance/ohms question

MSF06
HAZMAT
Joined: 10/04/05
Posts: 45
12/20/2005 11:22 pm
I have asked this else where but I figure the more places I ask the better my chances are of getting an answer.

From what little I know about electronics I have always thought that if I have a current running through something other then the wire that caused 8ohms of resistance and then added another 8ohms of resistance I would have a total of 16ohms. So my questions are...

1) If I run two cabs of 8ohms each "daisy chained", why would it bring the resistance down to 4ohms per cab and not raise it to 16?
2) If an amp can handle/push up to 16ohm then why would running it through 2, 4, or 8ohms cause it to have a melt down so to speak?

I have thought about it and can not figure out what is going on. I have emailed a few manufacturers and have had no response. I am guessing the answer is so simple that I am over looking it. :confused:

MSF
[FONT=Franklin Gothic Medium]Practice does not make you perfect. Perfect practice makes you perfect.[/FONT]
HDJ
Explanation: Southerner
Joined: 05/10/04
Posts: 1,445
12/20/2005 11:26 pm
The measure of Impedance works backwards.....4 ohms is less resistance than 8 ohms, and 8 ohms is less resistance than 16 ohms. So, the lower the number, the lower the resistance which means more power.

I hope I worded that right and in a way thats understandable.
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Havoc Din
MSF06
HAZMAT
Joined: 10/04/05
Posts: 45
12/20/2005 11:45 pm
Originally Posted by: JFRICKThe measure of Impedance works backwards.....4 ohms is less resistance than 8 ohms, and 8 ohms is less resistance than 16 ohms. So, the lower the number, the lower the resistance which means more power.

I hope I worded that right and in a way thats understandable.

I was thinking it was something like that. So, correct me if I am wrong, if the resistance is lower the speakers will draw more power from the head?

That I can understand but I still ask, why if there are two 8ohms in line does the resistance drop to 4ohms? Should it not be 16?

MSF
[FONT=Franklin Gothic Medium]Practice does not make you perfect. Perfect practice makes you perfect.[/FONT]
bsnake27
Registered User
Joined: 11/04/05
Posts: 4
12/21/2005 5:33 am
WWW.MARKTAW.COM/RECORDING/ELECTRONICS/OHMSAMPSANDSPEAKERS.HTML
sailorjim
Registered User
Joined: 11/23/05
Posts: 109
12/21/2005 7:31 am
Electronic 101 The calculation for Resistance in series is R1+R2= Rt
example 8ohms + 8 ohms = 16 ohms

However your cabs are connected in Paralell That calculation if the resistors are the same value is:

Resistance 8 ohms
--- = 4 Ohms
2 total number of resistors

--------------------------------------- +
I I
8 ohms 8 ohms
I I
--------------------------------------- -

If they are not the same the calculation is R1 x R2
------- = Total Resistance
R1 + R2

If your speakers were wired like - Speaker + ----- - Speaker + that would be in series

This is how it comes out of the Jack
+ ________________________________ +
CAB 8 ohms CAB 8 ohms
- ________________________________ _

Since you have less resistace this means you have more Power... And More Current So look at the rating on your CABS so you don't blow the snot out of them....

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sailorjim
Registered User
Joined: 11/23/05
Posts: 109
12/21/2005 7:39 am
Sorry HTML screwed up my examples

Resistace the same
8ohms / 2 resistors= 4 ohms

or
Resistance differnt
R1 X R2 / R1 + R2 = R total
A drunkard's dream if I ever did see one
MSF06
HAZMAT
Joined: 10/04/05
Posts: 45
12/21/2005 1:39 pm
Originally Posted by: sailorjimSorry HTML screwed up my examples

Resistace the same
8ohms / 2 resistors= 4 ohms

or
Resistance differnt
R1 X R2 / R1 + R2 = R total

I actually understood your first post :D I built the cabs my self so I know they are 8ohms each and my amp can handle down to 2ohms so I believe I am good to go.

Thanks for the info.

Here are other questions (if ya dont mind me askin'),

If I build a 4ohm cab would it be alright to run it in-line with an 8ohm cab (would give 2.66ohms) or should I run it off a different jack from the amp (may be even a second amp)?
Would the amp try to power the cab with lower resistance causing the higher resistant cab to blow?
If the cabs were in line would it make a difference if the 4ohm cab was before of after the 8ohms cab?

If you could recomend a good book or web site that deals with the resistance of speakers that would be good as well.

MSF
[FONT=Franklin Gothic Medium]Practice does not make you perfect. Perfect practice makes you perfect.[/FONT]
sailorjim
Registered User
Joined: 11/23/05
Posts: 109
12/21/2005 4:19 pm
Originally Posted by: MSF06I actually understood your first post :D I built the cabs my self so I know they are 8ohms each and my amp can handle down to 2ohms so I believe I am good to go.

Thanks for the info.

Here are other questions (if ya dont mind me askin'),

If I build a 4ohm cab would it be alright to run it in-line with an 8ohm cab (would give 2.66ohms) or should I run it off a different jack from the amp (may be even a second amp)?
Would the amp try to power the cab with lower resistance causing the higher resistant cab to blow?
If the cabs were in line would it make a difference if the 4ohm cab was before of after the 8ohms cab?

If you could recomend a good book or web site that deals with the resistance of speakers that would be good as well.

MSF

If your Amp is rated for 2 - 16 ohms you should be ok, because you would not be going bellow the 2 ohms--

Here is a website I found. I was going to give you all the calculations but this site does it alot better. They are decribing a car system, but it is still the same..
http://www.termpro.com/articles/spkrz.html
A drunkard's dream if I ever did see one
MSF06
HAZMAT
Joined: 10/04/05
Posts: 45
12/21/2005 9:33 pm
Thanks for the link. I did a search and came up with a lot of sites for car systems but was not sure how related they were.

Ok, my last questions ( I feel like such a noob :o ), on my amp there are two output jacks and it states, "2ohms minimum total load". I am guessing, since it says "min. total", that it is refering to both jacks combined or does it mean min. total per side? (I sent Carvin an email about 2 weeks ago but have not heard back from them.)

Here is the senario, if I "daisy chain" to 8ohm cabs(stack 1) that will be 4ohms. If I do that with a second set that will be another 4ohms (stack 2). So if I run stack 1 off one jack and stack 2 off the other will that bring me to 2ohms? ( I am going to read through that site you gave so that might give me the answer but I thought I would ask anyways.

Again thanks for the help

MSF
[FONT=Franklin Gothic Medium]Practice does not make you perfect. Perfect practice makes you perfect.[/FONT]
Lordathestrings
Gear Guru
Joined: 01/18/01
Posts: 6,242
12/21/2005 11:14 pm
~sigh~ You guys really oughta use the search tool!

>Ohms<
Lordathestrings
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MSF06
HAZMAT
Joined: 10/04/05
Posts: 45
12/21/2005 11:39 pm
Originally Posted by: Lordathestrings~sigh~ You guys really oughta use the search tool!

>Ohms<

FYI m'Loard but I did for my first question and nothing came up with a specific answer. The other questions I just figured would fit right along with the first. :cool:

MSF
[FONT=Franklin Gothic Medium]Practice does not make you perfect. Perfect practice makes you perfect.[/FONT]