ohm and wattage question
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=16501
Printed Date: June 09, 2024 at 6:49 AM
Topic: ohm and wattage question
Posted By: Lytheum
Subject: ohm and wattage question
Date Posted: July 20, 2003 at 11:21 PM
Hi all (<-first post) I am looking into getting new subs for my car. They are Adire Audios 12" Shiva's. I am trying to find the right amp to power them. I was looking at the JBL 600.1. This is where my question comes in. The amp puts out 600w rms @ 2ohm. If I wire both subs in parallel the final load at the amp will be 2 ohm. Each subs load would be 4 ohms. Would each sub draw 300w because it is wired at 4 ohm or would each sub draw 600w because thats the final load? Thanks Lyth
Replies:
Posted By: nedgeworth
Date Posted: July 20, 2003 at 11:26 PM
Each sub would be drawing 300w from that setup. Amp puts out 600 so divid that by 2 subs and you come out with 300 each.
Posted By: bfog99
Date Posted: July 22, 2003 at 11:02 AM
I think that the output from the 600.1 is 600 watts @ 2 ohms peak output, not RMS.
Posted By: Lytheum
Date Posted: July 22, 2003 at 6:37 PM
hmm....from what i read it actually puts out a little over 600w rms. Ill have to look into it more.
Posted By: nedgeworth
Date Posted: July 22, 2003 at 6:59 PM
Actually if you have it wired up to run at 4 ohm you will only be getting 150rms per sub. On a 2 or 1 ohm load you will get 300 each. My mistake for misreading there.
Posted By: bfog99
Date Posted: July 22, 2003 at 7:10 PM
Heres a site that shows the power ratings. https://www.sounddomain.com/sku/JBLBP6001
Posted By: Lytheum
Date Posted: July 23, 2003 at 9:16 PM
well the load at the amp would be 2 ohm. Each sub is dual 8 ohm so wired in parallel they are 4 ohm. Then both subs connect to the amp makeing it a 2 ohm load(4 ohm and 4 ohm would yeild 2ohm in parallel. The amp would then produce 600w. Each sub would get half of that.....atleast thats how I am understanding this. The whole Dual voice coils and 2 subs running off one amp has me a bit confused as to how it distributes the power
Posted By: donkason
Date Posted: July 23, 2003 at 10:13 PM
If you ran the amp at 1 channel bridged to 2 4 ohm speakers in parallel you would be delivering 600 watts to each sub.
Posted By: nedgeworth
Date Posted: July 23, 2003 at 10:19 PM
Ok effectively it's just like running two single 4ohm subs in parallel which the amp will see as 2ohms. The amps puts out 600 so yeap you've got your thinking straight. So 300 a piece.
Posted By: wvsquirrel
Date Posted: July 23, 2003 at 10:27 PM
The BP600.1 is a Mono amp, rated 600 x 1 @ 1 or 2 ohms based on a 14.4 volt electrical system. The amp has 2 sets of terminals for ease of wiring multiple subs, but it is Internally bridged already making it a technical 1 channel amp. Regardless if you use 1 or both sets of terminals, you still only have 1 real channel. If you wire only 1 sub to the amp, then you would only use 1 set of the terminals, not the + from 1 and the - from the other. If you wire 2 subs to it, then you put sub1 on one channel, and sub2 on the other. When you figure out the total ohm rating, you still base it on 1 channel (even though you are using 2 due to the internal bridge). It's confusing at first, but if you do an external bridge on that amp you run a serious risk of producing less than a 1ohm load without even realizing it.
In Lytheum's case, you would wire each DVC to it's own channel in parallel. Using 8ohm DVC's will yield 4ohms per terminal set, 2ohms overall due to the internal bridge. You will receive apx. 600 x 1 @ 2ohms, or 300 watts per sub. If you want a diagram let me know and I'll e-mail you one since I still can't post pics on the new 12volt server
------------- Squirrel
"No more Cpt. Kirk chit chat"
If its too loud, then you're too old
Donate to the12volt.com
Posted By: Lytheum
Date Posted: July 24, 2003 at 4:53 PM
wvsquirrel wrote:
The BP600.1 is a Mono amp, rated 600 x 1 @ 1 or 2 ohms based on a 14.4 volt electrical system. The amp has 2 sets of terminals for ease of wiring multiple subs, but it is Internally bridged already making it a technical 1 channel amp. Regardless if you use 1 or both sets of terminals, you still only have 1 real channel. If you wire only 1 sub to the amp, then you would only use 1 set of the terminals, not the + from 1 and the - from the other. If you wire 2 subs to it, then you put sub1 on one channel, and sub2 on the other. When you figure out the total ohm rating, you still base it on 1 channel (even though you are using 2 due to the internal bridge). It's confusing at first, but if you do an external bridge on that amp you run a serious risk of producing less than a 1ohm load without even realizing it.
In Lytheum's case, you would wire each DVC to it's own channel in parallel. Using 8ohm DVC's will yield 4ohms per terminal set, 2ohms overall due to the internal bridge. You will receive apx. 600 x 1 @ 2ohms, or 300 watts per sub. If you want a diagram let me know and I'll e-mail you one since I still can't post pics on the new 12volt server
sure......email me the diagram if ya dont mind ( Lytheum at Adelphia dot net ) Whats more confusing is conflicting answers I have been finding. The way you just and the other guy explained it make sense to me, but then there are the people that say each sub will get 600w which doesn't make sense to me. I just want to make sure before I buy because 600w to the sub will probably blow it.
Posted By: nedgeworth
Date Posted: July 24, 2003 at 4:56 PM
Lytheum, i use to have the same problem when ppl explained it too me. Then i ended up asking my old man who is an Electronic technian and he set me straight. But yeah i was a little taken back again when i say a post saying you would get 600 per sub.
Posted By: wvsquirrel
Date Posted: July 24, 2003 at 9:13 PM
You have to look at the total RMS output per channel, then divide that by the number of subs on that channel. The JBL BP series makes it a little more difficult to understand because it has 2 physical sets of + and -, but they are really just the same channel. I guess people got tired of wiring 2 subs to the same channel, so JBL thought it would be easier to offer 2 sets of + and - for ease of installation, while retaining the Mono function. But, if you aren't familiar with those amps then you could easily think it is a 2-channel amp just by the look. However, the power rating is 600 x 1, not 600 x 2. The rating references the number of watts produced per the number of channels listed. So a 600 x 1 amp will distribute 600 watts total over 1 channel. A 600 x 2 amp will distribute 600 watts per channel, or 1200 watts overall. To divide the watts per number of subs, you simply divide the per channel rating by the number of subs on that channel as I said before. So, a 600 x 1 amp running 2 subs will:
1) Distribute 600 total watts to the 1 channel
2) Each sub will receive 300 watts (Total channel RMS/#subs on that channel = 600/2 = 300 watts per sub)
I'll send the pic as soon as I can ------------- Squirrel
"No more Cpt. Kirk chit chat"
If its too loud, then you're too old
Donate to the12volt.com
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