well thats my question and im rather lost at what you guys are always talking about in other peoples topics.......
*me is verrrrrrrrrrrrrrry slow sometimes............*
Replies (12)
P0werLifter on 08/20/2004 14:26:36
An ohm is a unit of measure of a devices resistance to electrical current. All devices are designed to operate to design in some sort of load range. The lower the ohm, the more power is allowed through the device, but is more unstable and cause more heat, etc. The higher the ohm, the more restriction, less current is allowed through, but safer operation and more stable.
Every subwoofer, amplifier is designed to run on a certain ohm load. In subwoofers, for example we have 2,4,8 etc ohm loads. When you wire subwoofers, there are different ways to do so in order to net a certain ohm load. When you wire subwoofers in parralel ( Each driver wire +/+,,,-/- to amplifier) will lower the total ohmage load for the amplifier. When wiring in Series/parralel (if you have a dual voice coil amlifier) will net about the same ohm load rated on the subwoofer depending on how many drivers (subwoofers) you are running. Have i lost you yet? i hope not
-Heres a website that shows what im talking about as far as wiring possibilities for netting a certain ohm load
http://www.phoenixgold.com/tutorial/tutor.htm
When talking about amplifiers, we usually talk about 1,2,4 ohm load ratings. (Most are rated to work efficiently and correctly at 2,and 4 ohm) When you connect a load (subwoofers) to an amplifier, depending on the netted ohm load of those subwoofers will determine the overall power that is available from the amplifier (depending if its a 2-4ohm amplifier and how the subwoofers are ran.) If the subwoofers are wired in 2 ohm, and the amplifier is rated at 2 ohms. it will deliver good clean power. Now if you have wired the subwoofers to net a 1ohm load, and try to run them off a 2 ohm amplifier, the amplifier will get hot, and go into protection mode due to not being able to produce the correct power at that lvl of resistance.
I Hope this makes some sense, im sure one of the others will be here soon to help you more, as im not quite as well versed on this topic as some of the others.
-Jason
swez on 08/20/2004 18:44:15
PL is right on with his explanation... but there is more too. A speaker will change resistance at differrnt frequencies too. This is called inductive impedance loading.
Since the voice coil in a speaker is made up of wire, wrapped around a bobbin, it acts like an electromagnet when power is applied to the coil. The change in polarity (AC music signals) changes the field (magnetic poles) and direction of the coil as it moves in and out of an air gap with a large permanent magnet as a stable magnetic field that does not change. This is physics and electromagnetism combined with AC voltage. Very complex things going on in speaker as it does its magic.
Well, as the cone moves in and out of the fixed magnetic field (big magnet and pole piece common to all woofers) the resistance changes constantly in relationship to where the coil is located during its travels, in and out of the permanent magnetic field. It is measurable too.
If you hooked up a sub w/ no power applied, to an ohmeter and manually pressed the cone in and pulled it back up again, you would see a slight change in the resistance readings on the meter. But that is just static changes of coil resistance you are observing. It's even more dramatic when AC signals are applied to the coil.
Finally, voice coils are like other inductors. They change resistance value with frequency. This is how we use passive crossovers to regulate how much power gets to a speaker in a given range of frequencies. The coil inductor will increase in value considerably as the frequency goes up. That acts like a variable resistor to control load resistance to the speaker at a given frequency. Pretty complex math here is involved in designing a good crossover too. Anyway, for those who want to dig deeper, this is information is for you.
Hope this helps,
Swez
PS Made a post a few weeks back asking about 3-way passive crossovers for my current audio project. Nobody took the bait, so have been digging out information on crossover designs on my own. Have been building my own crossover networks now and will be testing the results soon.
Hope my calculations and phase relationships are correct in the present design. It's been a good learning experience too. Although a crossover uses simple looking devices... they are actually very complex in regard to how they all work together in a given circuit.
ssallstar598 on 09/11/2004 23:10:43
alright i get it sorta - just 1 thing.... how do u wire for ohms? as Power was talking about
If the subwoofers are wired in 2 ohm, and the amplifier is rated at 2 ohms. it will deliver good clean power. Now if you have wired the subwoofers to net a 1ohm load, and try to run them off a 2 ohm amplifier, the amplifier will get hot, and go into protection mode due to not being able to produce the correct power at that lvl of resistance.
how would i wire it that way?
P0werLifter on 09/12/2004 01:52:08
Its rather simple, the actual wiring part, go here and it'll show you
maby different wiring possiblities for Single Voice Coil, and Dual Voice coils.
http://www.phoenixgold.com/tutorial/tutor.htm
If you've wired a pair of DVC 2 ohm subs in series/parallel that will net 2ohm load. If you connect that with a 2ohm stable amplifier that will give you clean stable power (its what that amplifier is built for)
Now if you try to run the same set of 2ohm DVC in parralel that wil net a .5 ohm load. If you try to run that off of the same 2ohm amplifier, then it will not work, the amplifier will become very hot and go into protect mode, (that amplifier is not built to be stable at .5 ohms...some amplifiers are 1ohm stable)
-Jason
swez on 09/12/2004 21:34:18
The main goal in amplification, is to match the amps' greatest output (watts) to the load (subs) connected to the amp. This is true no matter what class of amplifier we choose.
Class A/B (most common in full range, 2/4/5/6 channel amplifiers), Class D MONO amps (1 channel, bass only) and Class T amps. (can be full range and bass too) They are typically found in multichannel amp applications too.
Another aspect of amplifiers, is the High Current (HC) style amps used in many high SPL (DB Drags) compititions. The are usually 2 channel, Class A/B technology and have the unique ability to run under 1 ohm loads. This amp design is raw power output. Power increases rapidly as we drop from a 4 ohm load, to something near 1 or less ohms. The main drawback with this amp... it's very power hungry and can demand huge amounts of current when operating under 2 ohm loads and less.
The main "take-a-way" here.... choose the amp based on the subs you plan to use OR, if you have the amp already, choose the proper subs that will net the highest output watts from that amp. We'll walk you through these steps as needed. No need to wrack your brain on the matter. We'll help out as you ask.
Swez
PS Me sloooooowww too sometimes! GRIN
ssallstar598 on 09/13/2004 10:27:45
ok well what kind of amp would i need to get for 2 12' Dual subs thats are 4 ohms nominal 600 watts RMS 1100 peak? id like to get a really nice brand of amp so it will be worth the money
swez on 09/13/2004 12:37:41
A simple Class D amp that is stable at 2 ohms is fine. Something that nets close too 600 RMS @ 2 ohms will be fine.
Amps: JL 500/1, JBL BP-600.1, Kicker KX-600.1, HiFonics, Phoenix Gold Octane series and many more as well.
Swez
ssallstar598 on 09/13/2004 16:52:39
swez - im lookin at getting sum 5 inch speakers (they might be 4 1/2 inch) and im not looking at hookin up to an amp - got any suggestions on replacing my stock bose?
swez on 09/13/2004 19:23:41
Need to know what size will fit in that cavity. Since this Caddy is pretty old, hard to say what you have in there, until you pull one out.
If you do not plan to amp these speakers, the Bose amp system may or may not have to be removed from the signal path. That means running new speaker wires from the Aftermarket HU to these new speakers.
Brands to consider: Alpine, Infinity, CDT, MA Audio, Audiobahn, JBL or many others too. Avoid cheap 3/4-way coaxial designs. A quality 2-way speaker will generally sound better than 3 or 4 way cheapies.
Since you are running them off the HU amps only, consider high efficiency models like Bahn. These have efficiency ratings of >90dB @ 1 watt.
Swez
ssallstar598 on 09/13/2004 20:06:33
no idea what 90db @ 1 watt means.... but currently ive got all new speaker wire running to the HU (speaker wire was shot when i got the car) and didnt know anything about the bose amp.... but they are 4 1/2 inch speakers tho
swez on 09/14/2004 07:58:05
The 90 dB @ 1 watt means the speaker will generate 90 dB worth of audio energy with only 1 watt of input power at 1 meter distance from the cone. This dB level is about what you would hear from a lawn mower running from a few feet away.
If you can fit 5.25" speakers in front doors, that would be a good option to use. May have to make a spacer for them to fit well. Many make their own with 1/2" - 3/4" MDF. They need to be air tight to door panel mounting location.
Finally, small speakers cannot do bass very well. You can install "Bass Blocker" filtering capacitors to block the lows below say 100 Hz.
Swez
PS The filter cap value will be ~400 uF and non-polorized too. Connected to the + wire of HU---------(
ssallstar598 on 09/14/2004 12:36:43
so really in theory i shouldnt bother getting new 4 inch speakers....? (i finally measured w/ a tape measure)
my dad duznt want me to put holes in the car for bigger speakers otherwise id already have 4 6x9 speakers in it
*me is verrrrrrrrrrrrrrry slow sometimes............*
Replies (12)
P0werLifter on 08/20/2004 14:26:36
An ohm is a unit of measure of a devices resistance to electrical current. All devices are designed to operate to design in some sort of load range. The lower the ohm, the more power is allowed through the device, but is more unstable and cause more heat, etc. The higher the ohm, the more restriction, less current is allowed through, but safer operation and more stable.
Every subwoofer, amplifier is designed to run on a certain ohm load. In subwoofers, for example we have 2,4,8 etc ohm loads. When you wire subwoofers, there are different ways to do so in order to net a certain ohm load. When you wire subwoofers in parralel ( Each driver wire +/+,,,-/- to amplifier) will lower the total ohmage load for the amplifier. When wiring in Series/parralel (if you have a dual voice coil amlifier) will net about the same ohm load rated on the subwoofer depending on how many drivers (subwoofers) you are running. Have i lost you yet? i hope not
-Heres a website that shows what im talking about as far as wiring possibilities for netting a certain ohm load
http://www.phoenixgold.com/tutorial/tutor.htm
When talking about amplifiers, we usually talk about 1,2,4 ohm load ratings. (Most are rated to work efficiently and correctly at 2,and 4 ohm) When you connect a load (subwoofers) to an amplifier, depending on the netted ohm load of those subwoofers will determine the overall power that is available from the amplifier (depending if its a 2-4ohm amplifier and how the subwoofers are ran.) If the subwoofers are wired in 2 ohm, and the amplifier is rated at 2 ohms. it will deliver good clean power. Now if you have wired the subwoofers to net a 1ohm load, and try to run them off a 2 ohm amplifier, the amplifier will get hot, and go into protection mode due to not being able to produce the correct power at that lvl of resistance.
I Hope this makes some sense, im sure one of the others will be here soon to help you more, as im not quite as well versed on this topic as some of the others.
-Jason
swez on 08/20/2004 18:44:15
PL is right on with his explanation... but there is more too. A speaker will change resistance at differrnt frequencies too. This is called inductive impedance loading.
Since the voice coil in a speaker is made up of wire, wrapped around a bobbin, it acts like an electromagnet when power is applied to the coil. The change in polarity (AC music signals) changes the field (magnetic poles) and direction of the coil as it moves in and out of an air gap with a large permanent magnet as a stable magnetic field that does not change. This is physics and electromagnetism combined with AC voltage. Very complex things going on in speaker as it does its magic.
Well, as the cone moves in and out of the fixed magnetic field (big magnet and pole piece common to all woofers) the resistance changes constantly in relationship to where the coil is located during its travels, in and out of the permanent magnetic field. It is measurable too.
If you hooked up a sub w/ no power applied, to an ohmeter and manually pressed the cone in and pulled it back up again, you would see a slight change in the resistance readings on the meter. But that is just static changes of coil resistance you are observing. It's even more dramatic when AC signals are applied to the coil.
Finally, voice coils are like other inductors. They change resistance value with frequency. This is how we use passive crossovers to regulate how much power gets to a speaker in a given range of frequencies. The coil inductor will increase in value considerably as the frequency goes up. That acts like a variable resistor to control load resistance to the speaker at a given frequency. Pretty complex math here is involved in designing a good crossover too. Anyway, for those who want to dig deeper, this is information is for you.
Hope this helps,
Swez
PS Made a post a few weeks back asking about 3-way passive crossovers for my current audio project. Nobody took the bait, so have been digging out information on crossover designs on my own. Have been building my own crossover networks now and will be testing the results soon.
Hope my calculations and phase relationships are correct in the present design. It's been a good learning experience too. Although a crossover uses simple looking devices... they are actually very complex in regard to how they all work together in a given circuit.
ssallstar598 on 09/11/2004 23:10:43
alright i get it sorta - just 1 thing.... how do u wire for ohms? as Power was talking about
If the subwoofers are wired in 2 ohm, and the amplifier is rated at 2 ohms. it will deliver good clean power. Now if you have wired the subwoofers to net a 1ohm load, and try to run them off a 2 ohm amplifier, the amplifier will get hot, and go into protection mode due to not being able to produce the correct power at that lvl of resistance.
how would i wire it that way?
P0werLifter on 09/12/2004 01:52:08
Its rather simple, the actual wiring part, go here and it'll show you
maby different wiring possiblities for Single Voice Coil, and Dual Voice coils.
http://www.phoenixgold.com/tutorial/tutor.htm
If you've wired a pair of DVC 2 ohm subs in series/parallel that will net 2ohm load. If you connect that with a 2ohm stable amplifier that will give you clean stable power (its what that amplifier is built for)
Now if you try to run the same set of 2ohm DVC in parralel that wil net a .5 ohm load. If you try to run that off of the same 2ohm amplifier, then it will not work, the amplifier will become very hot and go into protect mode, (that amplifier is not built to be stable at .5 ohms...some amplifiers are 1ohm stable)
-Jason
swez on 09/12/2004 21:34:18
The main goal in amplification, is to match the amps' greatest output (watts) to the load (subs) connected to the amp. This is true no matter what class of amplifier we choose.
Class A/B (most common in full range, 2/4/5/6 channel amplifiers), Class D MONO amps (1 channel, bass only) and Class T amps. (can be full range and bass too) They are typically found in multichannel amp applications too.
Another aspect of amplifiers, is the High Current (HC) style amps used in many high SPL (DB Drags) compititions. The are usually 2 channel, Class A/B technology and have the unique ability to run under 1 ohm loads. This amp design is raw power output. Power increases rapidly as we drop from a 4 ohm load, to something near 1 or less ohms. The main drawback with this amp... it's very power hungry and can demand huge amounts of current when operating under 2 ohm loads and less.
The main "take-a-way" here.... choose the amp based on the subs you plan to use OR, if you have the amp already, choose the proper subs that will net the highest output watts from that amp. We'll walk you through these steps as needed. No need to wrack your brain on the matter. We'll help out as you ask.
Swez
PS Me sloooooowww too sometimes! GRIN
ssallstar598 on 09/13/2004 10:27:45
ok well what kind of amp would i need to get for 2 12' Dual subs thats are 4 ohms nominal 600 watts RMS 1100 peak? id like to get a really nice brand of amp so it will be worth the money
swez on 09/13/2004 12:37:41
A simple Class D amp that is stable at 2 ohms is fine. Something that nets close too 600 RMS @ 2 ohms will be fine.
Amps: JL 500/1, JBL BP-600.1, Kicker KX-600.1, HiFonics, Phoenix Gold Octane series and many more as well.
Swez
ssallstar598 on 09/13/2004 16:52:39
swez - im lookin at getting sum 5 inch speakers (they might be 4 1/2 inch) and im not looking at hookin up to an amp - got any suggestions on replacing my stock bose?
swez on 09/13/2004 19:23:41
Need to know what size will fit in that cavity. Since this Caddy is pretty old, hard to say what you have in there, until you pull one out.
If you do not plan to amp these speakers, the Bose amp system may or may not have to be removed from the signal path. That means running new speaker wires from the Aftermarket HU to these new speakers.
Brands to consider: Alpine, Infinity, CDT, MA Audio, Audiobahn, JBL or many others too. Avoid cheap 3/4-way coaxial designs. A quality 2-way speaker will generally sound better than 3 or 4 way cheapies.
Since you are running them off the HU amps only, consider high efficiency models like Bahn. These have efficiency ratings of >90dB @ 1 watt.
Swez
ssallstar598 on 09/13/2004 20:06:33
no idea what 90db @ 1 watt means.... but currently ive got all new speaker wire running to the HU (speaker wire was shot when i got the car) and didnt know anything about the bose amp.... but they are 4 1/2 inch speakers tho
swez on 09/14/2004 07:58:05
The 90 dB @ 1 watt means the speaker will generate 90 dB worth of audio energy with only 1 watt of input power at 1 meter distance from the cone. This dB level is about what you would hear from a lawn mower running from a few feet away.
If you can fit 5.25" speakers in front doors, that would be a good option to use. May have to make a spacer for them to fit well. Many make their own with 1/2" - 3/4" MDF. They need to be air tight to door panel mounting location.
Finally, small speakers cannot do bass very well. You can install "Bass Blocker" filtering capacitors to block the lows below say 100 Hz.
Swez
PS The filter cap value will be ~400 uF and non-polorized too. Connected to the + wire of HU---------(
ssallstar598 on 09/14/2004 12:36:43
so really in theory i shouldnt bother getting new 4 inch speakers....? (i finally measured w/ a tape measure)
my dad duznt want me to put holes in the car for bigger speakers otherwise id already have 4 6x9 speakers in it
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