Ohm Question - Page 2 - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


Audio (and aftermarket electronics) This is your place for alarms, remote starters, to brag about your system, exaggerate your db levels, or simply ask questions for stock or aftermarket audio. No Flames! (except from roasted amps)

Reply
 
 
 
Thread Tools Search this Thread
Old 04-18-2007, 12:32 PM   #11
Senior Member
Posts like a Turbo
 
black_friday's Avatar
 
Join Date: Dec 2006
Location: Cincinnati, Ohio
Posts: 484
Thanks: 0
Thanked 0 Times in 0 Posts
black_friday is on a distinguished road
Default

what you should do is run speaker wire from the amp but don't hook it up to your subs. play a test tone on your head unit with the volume turned up to where you normailly listen to it. measure the ouptu voltage at the ends of the speaker wire. Here is the formula that I use
VOLTAGE SQUARED DIVIDED BY RESISTANCE EQUALS= POWER. Your ouput voltage will vary as you adjust the gain.
So for example if you get it to read around 39 volts with a 2 ohm load, it should put out 760 watts but i would shoot for around 43 to 45 watts.
black_friday is offline   Reply With Quote
Old 04-18-2007, 02:32 PM   #12
Member
Posts like a V-Tak
Thread Starter
 
Join Date: May 2005
Location: South Florida
Posts: 65
Thanks: 0
Thanked 0 Times in 0 Posts
myrddin70 is on a distinguished road
Default

toastedoats,

4 Ohm DVC (Dual Voice Coil) is what I am guessing DVC is for.

Thanks Brian, will keep that in mind.
myrddin70 is offline   Reply With Quote
Old 04-18-2007, 02:51 PM   #13
Senior Member
True Car Nut
 
toastedoats's Avatar
 
Join Date: Sep 2004
Location: Fitchburg Ma _ToastedRice_
Posts: 6,837
Thanks: 0
Thanked 0 Times in 0 Posts
toastedoats is on a distinguished road
Default

if they are dual 4ohm, then you can run 2 speakers at 4ohm.

however, you sig says P312D2 - which is a model number for ohm DVC.. P312D4 would be dual 4
toastedoats is offline   Reply With Quote
Old 04-18-2007, 02:58 PM   #14
Member
Posts like a V-Tak
Thread Starter
 
Join Date: May 2005
Location: South Florida
Posts: 65
Thanks: 0
Thanked 0 Times in 0 Posts
myrddin70 is on a distinguished road
Default

I guess i need to change the sig.

I am not 100% sure what I have. I do know this, a week ago we put a meter to the speaker jack on the box and it read 1.85-1.97. So thats 2 Ohms. The guy that metered them and installed them said they were 4 ohm speakers and there dual voice coil. So I guess he wired the dual voice coils together..making it 2 ohm load. I am not sure how that works.

The other thing I know is that the amps are running in 2 Ohm. That is what confuses me. Everything in my trunk is 2 Ohm load, but the speakers are 4 Ohm speakers..

I don't know. Just confused.
myrddin70 is offline   Reply With Quote
Old 04-18-2007, 03:12 PM   #15
Senior Member
Posts like a Turbo
 
black_friday's Avatar
 
Join Date: Dec 2006
Location: Cincinnati, Ohio
Posts: 484
Thanks: 0
Thanked 0 Times in 0 Posts
black_friday is on a distinguished road
Default

sounds like you got dual 4 ohm subs bridged to each amp to me
black_friday is offline   Reply With Quote
Old 04-18-2007, 03:50 PM   #16
Senior Member
True Car Nut
 
toastedoats's Avatar
 
Join Date: Sep 2004
Location: Fitchburg Ma _ToastedRice_
Posts: 6,837
Thanks: 0
Thanked 0 Times in 0 Posts
toastedoats is on a distinguished road
Default

did it measure 2 ohms for one speaker, or was it for the pair?

like, is there one set of speaker jacks, or two?
toastedoats is offline   Reply With Quote
Old 04-18-2007, 05:30 PM   #17
Member
Posts like a V-Tak
Thread Starter
 
Join Date: May 2005
Location: South Florida
Posts: 65
Thanks: 0
Thanked 0 Times in 0 Posts
myrddin70 is on a distinguished road
Default

Brian, I orrigionally thought I had P3D122 - 2 Ohm speakers, but the guy at the shop says there 4 ohm. That is why I am soooooo confused. The jack ports show 2 Ohms on them. But if they are DVC, I guess each VC is 2 OHm..hence the 4 OHM total speaker rating. I guess.

toastedoats,
There is one jack per speaker. The jack has on set of inputs. 1 (+ )and 1 (-)

So this one jack goes to both voice coils in the one speaker. How they are wired up inside I am presuming are like the picture above, posted by Plurr.

I am guessing. But what I stated on the box is what I see. One Jack per speaker.
myrddin70 is offline   Reply With Quote
Old 04-18-2007, 08:20 PM   #18
Senior Member
Posts like a Turbo
 
black_friday's Avatar
 
Join Date: Dec 2006
Location: Cincinnati, Ohio
Posts: 484
Thanks: 0
Thanked 0 Times in 0 Posts
black_friday is on a distinguished road
Default

you should be able to combine the negatives on the negative bridge terminal and the positives to the positive and the amp will read a 4 ohm mono load which would give each sub right at 750 watts.
black_friday is offline   Reply With Quote
Old 04-19-2007, 02:52 AM   #19
Senior Member
Posts like a Turbo
 
Join Date: Feb 2005
Location: Toronto, Canada
Posts: 363
Thanks: 0
Thanked 0 Times in 0 Posts
Dutch2005 is on a distinguished road
Default

Take one of your P3'* out of the box and look at the sticker on the magnet for the model number.

If the model number is;

P3D412 = DVC 4 ohms per coil

OR

P3D212 = DVC 2 ohms per coil

Here are the links for the 2 different P3'*
Click on the woofer wiring tabs on the bottom of these links, to see wiring config.

4 ohm DVC
http://www.rockfordfosgate.com/produ...n_US&p_status=

2 ohm DVC
http://www.rockfordfosgate.com/produ...n_US&p_status=

Is this the Amp your looking at buying ?
Click on the Specification tab at the bottom of the linked page.

http://www.rockfordfosgate.com/produ...n_US&p_status=

This amp can handle 1, 2 & 4 Ohm loads

The load on the amplifer is determined by how you wire your subs.
Think of it this way the amplifer has eye'* and can only see what ever resistance you show it by way of wiring your subs.
Less resistance = more power (unless you drop the load too low then you put the amp into protection ex. 0.5 ohm load)
Ex.
750 watts x 1 at 4 ohm
2000 watts x 1 at 1 ohm

Dutch
Dutch2005 is offline   Reply With Quote
Old 04-19-2007, 11:04 AM   #20
Member
Posts like a V-Tak
Thread Starter
 
Join Date: May 2005
Location: South Florida
Posts: 65
Thanks: 0
Thanked 0 Times in 0 Posts
myrddin70 is on a distinguished road
Default

Thanks guys,

I guess that is what it boils down to is opening the sub box and seeing for myself what is in there and how it is wired up.

I was so hoping to not do that. But I guess I will have to.

Thanks for all your inputs.

I'll get back to you as soon as I do this.
myrddin70 is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Ohm question about speakers radomirthegreat Audio (and aftermarket electronics) 12 07-13-2011 11:17 AM
Question about Ohm in subs Maymybonnieliveforevr Audio (and aftermarket electronics) 40 08-03-2007 12:20 PM
2 ohm vs 4 ohm nagel79 Audio (and aftermarket electronics) 3 07-09-2006 10:15 AM
8 ohm vs 4 ohm 79ford Audio (and aftermarket electronics) 16 03-15-2004 11:32 PM
4 Ohm Speakers vs. 2 Ohm Auburn Audio (and aftermarket electronics) 15 02-29-2004 08:10 AM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 12:40 AM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.