Speakerplans.com Homepage
Forum Home Forum Home > General > Advanced Discussion
  New Posts New Posts RSS Feed - Question on ohms
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Question on ohms
 Post Reply Post Reply Page  12>
Author
Message
  Topic Search Topic Search  Topic Options Topic Options
Requiem View Drop Down
Registered User
Registered User
Avatar

Joined: 20 January 2011
Location: Hampshire
Status: Offline
Points: 434 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Requiem Quote  Post ReplyReply Direct Link To This Post Topic: Question on ohms
    Posted: 26 January 2012 at 9:45pm
Hi, just a quick one...

can i put an 8 ohm driver in series with a 16 ohm driver, and does that amount to 6 ohms? 
also when amplifying, do i take halfway between the 8 ohm output and the 4 ohm output as a rough guide to what the amp will be putting out @ 6 ohms?

or is it not as simple as that.
im not too sure so just asking to clear it up...

i have a pair of tops loaded with double 16ohm drivers and one got ripped apart by some idiot at a party in each top. i bought a pair of matching drivers to replace them with but they are slightly different, in nothing apart from the new ones are 8 ohm per driver and the other 2 working ones i will be coupling them with are 16ohm.

any info would be appreciated , cheers
-Requiem Soundsystem-
www.facebook.com/Requiem.Eventz
Back to Top
djeddie View Drop Down
Old Croc
Old Croc
Avatar

Joined: 26 April 2004
Location: Bristol
Status: Offline
Points: 1800 		Post Options Post Options   Thanks (0) Thanks(0)   Quote djeddie Quote  Post ReplyReply Direct Link To This Post Posted: 26 January 2012 at 10:17pm
It actually comes out as 5.333Ω. But you're right on roughly going halfway between the 4Ω and 8Ω rating.
The other thing to bear in mind is the 8Ω driver will have 2/3 of the power going to the cab with the 16Ω driver having the other 1/3. So with 300 watts to the cab, 200w will go through the 8Ω driver and 100w through the 16Ω driver in simple terms.
E=mc² ±3dB
Back to Top
MessyM2k8 View Drop Down
Registered User
Registered User
Avatar

Joined: 29 October 2008
Location: Norwich
Status: Offline
Points: 354 		Post Options Post Options   Thanks (0) Thanks(0)   Quote MessyM2k8 Quote  Post ReplyReply Direct Link To This Post Posted: 26 January 2012 at 10:37pm
Originally posted by Requiem Requiem wrote:

Hi, just a quick one...

can i put an 8 ohm driver in series with a 16 ohm driver, and does that amount to 6 ohms? 
also when amplifying, do i take halfway between the 8 ohm output and the 4 ohm output as a rough guide to what the amp will be putting out @ 6 ohms?

or is it not as simple as that.
im not too sure so just asking to clear it up...

i have a pair of tops loaded with double 16ohm drivers and one got ripped apart by some idiot at a party in each top. i bought a pair of matching drivers to replace them with but they are slightly different, in nothing apart from the new ones are 8 ohm per driver and the other 2 working ones i will be coupling them with are 16ohm.

any info would be appreciated , cheers


It'll be 16 + 8 which is 24ohms
Back to Top
MessyM2k8 View Drop Down
Registered User
Registered User
Avatar

Joined: 29 October 2008
Location: Norwich
Status: Offline
Points: 354 		Post Options Post Options   Thanks (0) Thanks(0)   Quote MessyM2k8 Quote  Post ReplyReply Direct Link To This Post Posted: 26 January 2012 at 10:38pm
A diagram of several resistors, connected end to end, with the same amount of current going through each
R_\mathrm{eq} = R_1 + R_2 + \cdots + R_n

A diagram of several resistors, side by side, both leads of each connected to the same wires
\frac{1}{R_\mathrm{eq}} = \frac{1}{R_1} + \frac{1}{R_2} + \cdots + \frac{1}{R_n}

nicked from wiki...
Back to Top
Requiem View Drop Down
Registered User
Registered User
Avatar

Joined: 20 January 2011
Location: Hampshire
Status: Offline
Points: 434 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Requiem Quote  Post ReplyReply Direct Link To This Post Posted: 26 January 2012 at 10:42pm
Ok, both drivers are 300w rms, so will i have problems getting the 16 ohm one to perform as well as it could without blowing the 8ohm one? is there any way i can avoid this by putting the 16 ohm driver first in the series or any other method?


seems to be a bit of a dilema, would i be better off putting both the 8 ohm drivers in one of the tops and both the 16 ohm drivers in the other one, bearing in mind they will both be going off the same amp, and turning up the side with the two 16 ohm drivers more?
they are exactly the same drivers aside from the Ω
-Requiem Soundsystem-
www.facebook.com/Requiem.Eventz
Back to Top
Requiem View Drop Down
Registered User
Registered User
Avatar

Joined: 20 January 2011
Location: Hampshire
Status: Offline
Points: 434 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Requiem Quote  Post ReplyReply Direct Link To This Post Posted: 26 January 2012 at 10:45pm
Originally posted by MessyM2k8 MessyM2k8 wrote:

 

It'll be 16 + 8 which is 24ohms




 im pretty sure thats wrong.... because as i understand it 2 8Ω  drivers make a 4Ω load, 3 make a 2.7Ω load and 4 8Ω make a 2Ω load


correct me if im wrong anyone 


Edited by Requiem - 26 January 2012 at 10:46pm
-Requiem Soundsystem-
www.facebook.com/Requiem.Eventz
Back to Top
MessyM2k8 View Drop Down
Registered User
Registered User
Avatar

Joined: 29 October 2008
Location: Norwich
Status: Offline
Points: 354 		Post Options Post Options   Thanks (0) Thanks(0)   Quote MessyM2k8 Quote  Post ReplyReply Direct Link To This Post Posted: 26 January 2012 at 10:49pm
Originally posted by Requiem Requiem wrote:

Hi, just a quick one...

can i put an 8 ohm driver in series with a 16 ohm driver,


you say series do you mean parallel?
Back to Top
Requiem View Drop Down
Registered User
Registered User
Avatar

Joined: 20 January 2011
Location: Hampshire
Status: Offline
Points: 434 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Requiem Quote  Post ReplyReply Direct Link To This Post Posted: 26 January 2012 at 11:23pm
i mean as in going from the amp to one driver and then on to another driver...
-Requiem Soundsystem-
www.facebook.com/Requiem.Eventz
Back to Top
knet94 View Drop Down
Registered User
Registered User
Avatar

Joined: 31 March 2008
Location: NW London
Status: Offline
Points: 535 		Post Options Post Options   Thanks (0) Thanks(0)   Quote knet94 Quote  Post ReplyReply Direct Link To This Post Posted: 26 January 2012 at 11:35pm
Inside the cabinet if the drivers are wired with both positives wired together (from the amp) and both negatives wired together (going back to the amp) then this is paralell.

If the positive from the amp goes to the positive of one driver and then the negative is connected to the positive of the other driver and then the negative goes back to the amp this is a series. You need to know which one as it's fundamental to calculating ohmage when using multiple drivers.

Hope that helps.
Back to Top
kedwardsleisure View Drop Down
Old Croc
Old Croc
Avatar

Joined: 20 January 2009
Location: Staffordshire
Status: Offline
Points: 1723 		Post Options Post Options   Thanks (0) Thanks(0)   Quote kedwardsleisure Quote  Post ReplyReply Direct Link To This Post Posted: 27 January 2012 at 12:20am
Quote i mean as in going from the amp to one driver and then on to another driver...



If you connect in parallel it is 5.33 ohms.
If you connect in series it is 24 ohms

I wouldn't do it either way unless uneven driving is your goal.

Find another solution.





Edited by kedwardsleisure - 27 January 2012 at 12:20am
K. Edwards Electronics Engineers

North Staffordshire
Back to Top
MessyM2k8 View Drop Down
Registered User
Registered User
Avatar

Joined: 29 October 2008
Location: Norwich
Status: Offline
Points: 354 		Post Options Post Options   Thanks (0) Thanks(0)   Quote MessyM2k8 Quote  Post ReplyReply Direct Link To This Post Posted: 27 January 2012 at 12:31am
Originally posted by Requiem Requiem wrote:

Ok, both drivers are 300w rms, so will i have problems getting the 16 ohm one to perform as well as it could without blowing the 8ohm one? is there any way i can avoid this by putting the 16 ohm driver first in the series or any other method?


seems to be a bit of a dilema, would i be better off putting both the 8 ohm drivers in one of the tops and both the 16 ohm drivers in the other one, bearing in mind they will both be going off the same amp, and turning up the side with the two 16 ohm drivers more?
they are exactly the same drivers aside from the Ω

Your best way is to match the drivers in the cabs and wire them in parallel, so you put both the 16ohm drivers in one cab in parallel (8ohms) and the 8ohm drivers in parallel (4ohms) in the other cab.
Back to Top
GEB View Drop Down
Registered User
Registered User
Avatar

Joined: 13 November 2009
Location: Lincs
Status: Offline
Points: 495 		Post Options Post Options   Thanks (0) Thanks(0)   Quote GEB Quote  Post ReplyReply Direct Link To This Post Posted: 27 January 2012 at 10:07am
Why is this in the 'advanced' section?

The best and easiest solution would be 4 matching drivers, eg; 8 ohms. Funds permitting of course. But then again, it probably won't be long before the 8 ohm drivers get too much power and blow anyway if they're matched with the 16 ohm drivers, costing you more in the long run!


Edited by GEB - 27 January 2012 at 10:08am
Back to Top
 Post Reply Post Reply Page  12>
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 10.10
Copyright ©2001-2012 Web Wiz Ltd.

This page was generated in 0.219 seconds.