confused watts
Printed From: the12volt.comForum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=16151
Printed Date: June 06, 2024 at 1:42 PM
Topic: confused watts
Posted By: msf145
Subject: confused watts
Date Posted: July 10, 2003 at 10:44 PM
Replies:
Posted By: ghs_wreslter189
Date Posted: July 10, 2003 at 10:56 PM
Posted By: wvsquirrel
Date Posted: July 10, 2003 at 11:56 PM
Root Mean Squared
It's a fancy name for the Continuous Power rating of the sub. Manufacturer's will specify what the RMS is of their subs, and it is used as the "Safe Spot" while still performing. The best rule to follow is to match the RMS of the sub to the RMS of the amp.
You also have a sub's "Peak" rating, or Maximum Power rating. This is basically the manufacturer's "Blow Up" power level. Meaning if you give the sub it's Peak wattage rating then you run a very good chance of blowing the sub. If you want to run the sub at higher then the RMS rating, then I usually recommend not going any higher then RMS + half the difference between the RMS and Peak rating [RMS + (Peak - RMS)/2]. But remember, if you supply more then the RMS rated power, you are running a risk of decreasing the life expectancy of the sub. It may perform better and be louder, but the sub wont last as long.
Here's an example...
Sub1 is rated at 500 watts RMS and 1000 watts Peak. Your safest wattage level is an amp that produces 500 watts RMS.
If you wanted more power, then I wouldn't go any higher than 750 watts
[500 + (1000 - 500)/2] = [500 + (500/2)] = [500 + 250] = 750
When choosing the amp, you have to take several things into consideration to make sure you can get the correct power that you want. Here's a few of the things you need to consider...
1) The number of Voice Coils the sub has (it's either 1 or 2, commonly referred to as Single Voice Coil and Dual Voice Coil).
2) The impodence (resistance rating) of the sub(s), commonly referred to as the Ohm rating.
3) The number of subs you are using.
These all have to do with the available wiring options to change the total ohm load that the amp sees.
Here's some examples of properly matching amps and subs...
(1) 4ohm SVC sub
Sub1 is a 4ohm Single Voice Coil sub rated 500RMS 1000Peak.
Since it is only (1) 4ohm SVC, you can only wire sub+ to amp+ and sub- to amp- and the total ohm load will not change. It would look like this...
And you would want an amp rated 500 watts x 1-channel @ 4ohms.
(2) 4ohm SVC subs
Sub1 is a 4ohm Single Voice Coil sub rated 500RMS 1000Peak.
Sub2 is a 4ohm Single Voice Coil sub rated 500RMS 1000Peak.
Now that you have more than 1 SVC sub, you have several wiring options available to use...
Parallel: Connecting Sub1+ and Sub2+ to amp+ and Sub1- and Sub2- to amp-. Wiring in parallel cuts the ohm load in half. So two 4ohm SVC subs wired in parallel would produce a 2ohm total load to the amp, and it would look like this...
Series: Connecting amp+ to Sub1+, Sub1- to Sub2+, and Sub2- to amp-. Wiring in series doubles the ohm load. So two 4ohm SVC subs wired in series would produce an 8ohm total load to the amp, and it would look like this...
An 8ohm load is not going to give much power, so you would want to look at the wiring configurations for 2 and 4 ohm loads. Using the specs from Sub1 and Sub2, you would want either a 1-channel amp rated 1000watts x 1-channel @ 2ohms (the total watts rating gets divided by the number of subs, so each sub would get 500watts), a 2-channel amp rated 500watts x 2-channels @ 4ohms (each sub wired to it's own channel), or a 4-channel amp rated 500watts x 2-channels @ 4ohms mono/bridged (when you bridge an amp you are combining 2 channels into 1, in this case channels 1 and 2 are being bridged into 1-channel, and channels 3 and 4 are being bridged into 1-channel, thus creating 2 mono bridges)
I know that can get confusing, so here's some links to a couple wiring diagrams that will allow you to adjust the number of subs, ohm rating, and SVC or DVC (think of 1 DVC as being equivilent to 2 SVC's).
JBL Wiring Wizard
JL Audio Wiring Wizard
Rockford Fosgate Wiring Wizard
I've always prefered the Rockford wizard, but the JL Audio wizard has a few more diagrams. It doesn't matter what the manufacturer of the sub is when you are looking at the wizards.
I hope I haven't confused you, and let me know if I can clarify anything further for you.
-------------
Squirrel
"No more Cpt. Kirk chit chat"
If its too loud, then you're too old
Donate to the12volt.com
It's a fancy name for the Continuous Power rating of the sub. Manufacturer's will specify what the RMS is of their subs, and it is used as the "Safe Spot" while still performing. The best rule to follow is to match the RMS of the sub to the RMS of the amp.
You also have a sub's "Peak" rating, or Maximum Power rating. This is basically the manufacturer's "Blow Up" power level. Meaning if you give the sub it's Peak wattage rating then you run a very good chance of blowing the sub. If you want to run the sub at higher then the RMS rating, then I usually recommend not going any higher then RMS + half the difference between the RMS and Peak rating [RMS + (Peak - RMS)/2]. But remember, if you supply more then the RMS rated power, you are running a risk of decreasing the life expectancy of the sub. It may perform better and be louder, but the sub wont last as long.
Here's an example...
Sub1 is rated at 500 watts RMS and 1000 watts Peak. Your safest wattage level is an amp that produces 500 watts RMS.
If you wanted more power, then I wouldn't go any higher than 750 watts
[500 + (1000 - 500)/2] = [500 + (500/2)] = [500 + 250] = 750
When choosing the amp, you have to take several things into consideration to make sure you can get the correct power that you want. Here's a few of the things you need to consider...
1) The number of Voice Coils the sub has (it's either 1 or 2, commonly referred to as Single Voice Coil and Dual Voice Coil).
2) The impodence (resistance rating) of the sub(s), commonly referred to as the Ohm rating.
3) The number of subs you are using.
These all have to do with the available wiring options to change the total ohm load that the amp sees.
Here's some examples of properly matching amps and subs...
(1) 4ohm SVC sub
Sub1 is a 4ohm Single Voice Coil sub rated 500RMS 1000Peak.
Since it is only (1) 4ohm SVC, you can only wire sub+ to amp+ and sub- to amp- and the total ohm load will not change. It would look like this...
And you would want an amp rated 500 watts x 1-channel @ 4ohms.
(2) 4ohm SVC subs
Sub1 is a 4ohm Single Voice Coil sub rated 500RMS 1000Peak.
Sub2 is a 4ohm Single Voice Coil sub rated 500RMS 1000Peak.
Now that you have more than 1 SVC sub, you have several wiring options available to use...
Parallel: Connecting Sub1+ and Sub2+ to amp+ and Sub1- and Sub2- to amp-. Wiring in parallel cuts the ohm load in half. So two 4ohm SVC subs wired in parallel would produce a 2ohm total load to the amp, and it would look like this...
Series: Connecting amp+ to Sub1+, Sub1- to Sub2+, and Sub2- to amp-. Wiring in series doubles the ohm load. So two 4ohm SVC subs wired in series would produce an 8ohm total load to the amp, and it would look like this...
An 8ohm load is not going to give much power, so you would want to look at the wiring configurations for 2 and 4 ohm loads. Using the specs from Sub1 and Sub2, you would want either a 1-channel amp rated 1000watts x 1-channel @ 2ohms (the total watts rating gets divided by the number of subs, so each sub would get 500watts), a 2-channel amp rated 500watts x 2-channels @ 4ohms (each sub wired to it's own channel), or a 4-channel amp rated 500watts x 2-channels @ 4ohms mono/bridged (when you bridge an amp you are combining 2 channels into 1, in this case channels 1 and 2 are being bridged into 1-channel, and channels 3 and 4 are being bridged into 1-channel, thus creating 2 mono bridges)
I know that can get confusing, so here's some links to a couple wiring diagrams that will allow you to adjust the number of subs, ohm rating, and SVC or DVC (think of 1 DVC as being equivilent to 2 SVC's).
JBL Wiring Wizard
JL Audio Wiring Wizard
Rockford Fosgate Wiring Wizard
I've always prefered the Rockford wizard, but the JL Audio wizard has a few more diagrams. It doesn't matter what the manufacturer of the sub is when you are looking at the wizards.
I hope I haven't confused you, and let me know if I can clarify anything further for you.
-------------
Squirrel
"No more Cpt. Kirk chit chat"
If its too loud, then you're too old
Donate to the12volt.com
Posted By: xetmes
Date Posted: July 11, 2003 at 6:14 AM
Posted By: msf145
Date Posted: July 11, 2003 at 2:17 PM
Posted By: StereoRep
Date Posted: July 12, 2003 at 11:30 PM