Is there any difference between the sound of 1 sub at 500 watt vs. 2 at
01-17-2006, 10:14 PM
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Is there any difference between the sound of 1 sub at 500 watt vs. 2 at 250 watts each? I'm wondering if one high power sub running off my amp will sound as good as 2 subs.
01-17-2006, 10:29 PM
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You need to be more specific.
It totally depends on which specific speakers you are thinking about using. While you want to select speakers rated to match the capabilities of your amp. Electrical power rating says nothing about sound quality, frequency response, or how loud they will actually be at a given volume setting.
It totally depends on which specific speakers you are thinking about using. While you want to select speakers rated to match the capabilities of your amp. Electrical power rating says nothing about sound quality, frequency response, or how loud they will actually be at a given volume setting.
01-18-2006, 08:08 AM
#3
i believe i read that two subs should be louder due to surface area of the cones raising the spl, doesnt necessarily mean it will sound better than one, but then again it could.... i got two 12" mtx5500s and a PG 400.1 amp and with two subs it is loud, with one sub hooked up it seems just as loud but the deepness seems to be gone and it doesnt hit as hard, but the bass seems to be just as loud. i think it really depends on the setup though.
01-18-2006, 08:35 AM
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If you assume identical subs, and assume that they remain within their linear range up to the 500watts, you will not notice a difference between 1 sub at 500 watts or 2 at 250 watts each.
01-18-2006, 08:41 AM
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My statement above also assumes the boxes the subs are in are identical. You gain 3db by doubling the surface area and then lose 3 db when you cut the power in half for a net gain of 0 db.
01-18-2006, 08:45 AM
#6
Given that the speakers are the same and the amp is identical.
it's just simple math. these are an example. Two speakers are louder than one. There's other factors, but assuming that the speakers are identical and are using the same amp.
Two speakers sharing out 500 watts, that's 250w per speaker. The output per speaker is we will say 50db each x2 will be about 100db.
A single speaker is 50db at 250 watts. The speaker will not double it's output by doubling the power. It may gain about 2-3db tops and some are slightly higher.
changing speakers, changing amps, etc will change the outcome. But general rules are two heads are better than one. same as speakers, two speakers are going to be louder than one giving the same speakers and using the same amp.
edit: this is theory, yes, i know that a single speaker can put out over 100db. There's just so many factors, but like i said, assuming same speakers and same amp.
it's just simple math. these are an example. Two speakers are louder than one. There's other factors, but assuming that the speakers are identical and are using the same amp.
Two speakers sharing out 500 watts, that's 250w per speaker. The output per speaker is we will say 50db each x2 will be about 100db.
A single speaker is 50db at 250 watts. The speaker will not double it's output by doubling the power. It may gain about 2-3db tops and some are slightly higher.
changing speakers, changing amps, etc will change the outcome. But general rules are two heads are better than one. same as speakers, two speakers are going to be louder than one giving the same speakers and using the same amp.
edit: this is theory, yes, i know that a single speaker can put out over 100db. There's just so many factors, but like i said, assuming same speakers and same amp.
Last edited by wickedwarlock; 01-18-2006 at 09:12 AM.
01-18-2006, 09:59 AM
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Originally Posted by wickedwarlock
Given that the speakers are the same and the amp is identical.
it's just simple math. these are an example. Two speakers are louder than one. There's other factors, but assuming that the speakers are identical and are using the same amp.
Two speakers sharing out 500 watts, that's 250w per speaker. The output per speaker is we will say 50db each x2 will be about 100db.
A single speaker is 50db at 250 watts. The speaker will not double it's output by doubling the power. It may gain about 2-3db tops and some are slightly higher.
changing speakers, changing amps, etc will change the outcome. But general rules are two heads are better than one. same as speakers, two speakers are going to be louder than one giving the same speakers and using the same amp.
it's just simple math. these are an example. Two speakers are louder than one. There's other factors, but assuming that the speakers are identical and are using the same amp.
Two speakers sharing out 500 watts, that's 250w per speaker. The output per speaker is we will say 50db each x2 will be about 100db.
A single speaker is 50db at 250 watts. The speaker will not double it's output by doubling the power. It may gain about 2-3db tops and some are slightly higher.
changing speakers, changing amps, etc will change the outcome. But general rules are two heads are better than one. same as speakers, two speakers are going to be louder than one giving the same speakers and using the same amp.
You are not correct in your statements,
1) 50 watts RMS (even to a single driver) should typically get you to between at least 95 to 105 db depending on the drivers, efficiency, and cabin gain, and frequency you are measuring at.
2) Doubling the number of drivers will absolutely not double the SPL, you can calculate the increase in efficiency by taking the log of the number of drivers x 10. example: log(2)x10=3 So if we expand on this we can see that:
2 drivers = +3dB , 3 drivers = +4.7dB, 4 = +6dB, 5 = +7dB, etc.
You also need to consider any change in resistance (or ohms)
to factor in the change in voltage sensistivity (dB/2.83V)
For 2 drivers taking the effect of load on the amplifier into account:
- 2 in parallel (two 4 ohm driver connected so the load = 2 ohms Vs. a single 4 ohm driver for example) gives +6dB (current is+3dB because resistance is half, and you gain +3 db for the extra driver).
- 2 in series (two 4 ohm drivers connected so the load = 8 ohms Vs. one 4 ohm driver for example) gives 0dB (current is -3dB because resistance is double, but you gain +3db for the extra driver).
For 3 drivers :
parallel = +9.5dB, series = 0dB.
For 4 drivers :
parallel = +12dB, series/parallel = +6dB, series = 0dB.
And I was also incorrect in my earlier statement, if you have a total of 500 watts feeding 2 drivers you will gain +3 db over 500 watts feeding one driver. I was having a brain fart. sorry.
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01-18-2006, 10:39 AM
#8
I well aware of basic electronics.
I am referring to as sharing the same load. I am very well aware of resistance are different but you are still pushing 500 watts under two loads and sharing the same box size.
say you have a 3 cubic foot box. with one 4 ohm speaker
the amp puts out 500 watts at 4 ohm.
now, we take the same 3 cubic foot box and put two speakers in it.
both speakers are wired that they have a 4 ohm load.
two speakers will move more air than one under these conditions. Like I said a general rule. Sure i could add more power add a bigger speaker. I am referring as the same setup. This is what makes it fun by choice Altering a box size, speaker size, more power will alter this.
If you want it to be loud, adding more woofers is generally more boom. Like I said before, there's many variations.
the numbers are theoritical as i have said above. I know they dont add up, but point being, two speakers move more air period under the same general conditions. Than you have sealed versus ported, like I said variations. I will see if I can find a few formulas for you. Like I said, the numbers above are made up and are by no means 100% adding, wow, otherwise, it would get interesting.
edit: yes, the rule you have is also a general rule, it's not always correct due to box size and sealing or porting it. Variations.
A single woofer can only move so much air, no matter how much power you give it.
I am referring to as sharing the same load. I am very well aware of resistance are different but you are still pushing 500 watts under two loads and sharing the same box size.
say you have a 3 cubic foot box. with one 4 ohm speaker
the amp puts out 500 watts at 4 ohm.
now, we take the same 3 cubic foot box and put two speakers in it.
both speakers are wired that they have a 4 ohm load.
two speakers will move more air than one under these conditions. Like I said a general rule. Sure i could add more power add a bigger speaker. I am referring as the same setup. This is what makes it fun by choice Altering a box size, speaker size, more power will alter this.
If you want it to be loud, adding more woofers is generally more boom. Like I said before, there's many variations.
the numbers are theoritical as i have said above. I know they dont add up, but point being, two speakers move more air period under the same general conditions. Than you have sealed versus ported, like I said variations. I will see if I can find a few formulas for you. Like I said, the numbers above are made up and are by no means 100% adding, wow, otherwise, it would get interesting.
edit: yes, the rule you have is also a general rule, it's not always correct due to box size and sealing or porting it. Variations.
A single woofer can only move so much air, no matter how much power you give it.
Last edited by wickedwarlock; 01-18-2006 at 10:52 AM.
01-18-2006, 12:39 PM
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Originally Posted by wickedwarlock
I well aware of basic electronics.
Originally Posted by wickedwarlock
I am referring to as sharing the same load. I am very well aware of resistance are different but you are still pushing 500 watts under two loads and sharing the same box size.
say you have a 3 cubic foot box. with one 4 ohm speaker
the amp puts out 500 watts at 4 ohm.
now, we take the same 3 cubic foot box and put two speakers in it.
both speakers are wired that they have a 4 ohm load.
two speakers will move more air than one under these conditions. Like I said a general rule. Sure i could add more power add a bigger speaker. I am referring as the same setup. This is what makes it fun by choice Altering a box size, speaker size, more power will alter this.
say you have a 3 cubic foot box. with one 4 ohm speaker
the amp puts out 500 watts at 4 ohm.
now, we take the same 3 cubic foot box and put two speakers in it.
both speakers are wired that they have a 4 ohm load.
two speakers will move more air than one under these conditions. Like I said a general rule. Sure i could add more power add a bigger speaker. I am referring as the same setup. This is what makes it fun by choice Altering a box size, speaker size, more power will alter this.
Putting 2 drivers in a box sized for one will change the frequency response of the drivers significantly. In your scenario, stuffing 2 drivers into a box sized for one may actually have a net decrease in SPL in the lower frequencies (20hz-50hz) while potentially giving more than a 3 db gain in the upper bass frequencies (50hz-100hz). I would suggest modeling the drivers in the box size you intend to use to ensure you get the desired response instead of guessing. You can still have the fun of choosing the right driver without the expense and headache of buying the wrong one. Of course that gets into box design and is beyond the scope of the posters original question.
Originally Posted by wickedwarlock
If you want it to be loud, adding more woofers is generally more boom. Like I said before, there's many variations.
Originally Posted by wickedwarlock
the numbers are theoritical as i have said above. I know they dont add up, but point being, two speakers move more air period under the same general conditions. Than you have sealed versus ported, like I said variations.
Originally Posted by wickedwarlock
A single woofer can only move so much air, no matter how much power you give it.
01-18-2006, 01:03 PM
#10
You are correct, I shouldn't of given examples of db. I should of left the numbers out, this would elimante any confusion. I guess it's just hard to explain on paper, unlike explaing it over the phone. 
I guess it's just hard to explain on paper, unlike explaing it over the phone. 
01-22-2006, 09:25 AM
#12
LOL spy. That's pretty funny.
Ok. Here is a simple rule of thumb concerning gain:
2x the conage area (same power) = +3 dB
2x the power = +3 dB
2x the power and 2x the coneage area= +6 dB
That's all I'm adding. TAguy covered the rest well enough as far as theoretical gain goes.
Now, theory is almost never perfect in the real world. We use the theory because it is the most accurate guess that can be made. For guessing the dB output, the measure amount will be very close to the theory. But here are some other factors to consider besides the basic physic's: Phyco-Accoustic effects.
The measured amount for the doubling of volume is 3dB. It take a 2x increase in either cone area (sD) or Power (RMS) to measure the Double volume.
Our ears perceive sound in a different way. (This is what I remember well from a test Pioneer performed in it's vehicle sound lab) The Average person does not perceive a doubling of volume until in the 8-10 dB gain area.
What that means as far as power goes is this: You would need roughly 9 dB gain to "Hear" something twice as loud. That means you almost need to quadruple the output to perceive the volume to be twice as loud. 1-2 dB was the amount needed to Hear a change in volume. (roughly a 2dB value there)
So, the 1 sub at 500 watts would need to become 8 subs (62.5 w per sub or 500w total) to be "Twice as Loud" or go from 1 sub 500w to 1 sub 4000w. Remember this: For every 3 dB gain, you have to DOUBLE the value before it.
Here's a quick example: 1-2-4-8 or 2-4-8-16.
There are other factors to be concerned with on how to maximise the effectiveness of a set-up (Minimizing cancelations) but I'd throw this out to you guy's to chew on. There are also alot of other smaller details to know to get the most out of a set-up. Hell, porting a sub and firing it in the right direction can net measured gains up to 10 dB.
Final thing (since I don't get a chance to get on the net much) is this: It's all about the installation, not the individual parts. Same thing apply's to building our cars.
Ok. Here is a simple rule of thumb concerning gain:
2x the conage area (same power) = +3 dB
2x the power = +3 dB
2x the power and 2x the coneage area= +6 dB
That's all I'm adding. TAguy covered the rest well enough as far as theoretical gain goes.
Now, theory is almost never perfect in the real world. We use the theory because it is the most accurate guess that can be made. For guessing the dB output, the measure amount will be very close to the theory. But here are some other factors to consider besides the basic physic's: Phyco-Accoustic effects.
The measured amount for the doubling of volume is 3dB. It take a 2x increase in either cone area (sD) or Power (RMS) to measure the Double volume.
Our ears perceive sound in a different way. (This is what I remember well from a test Pioneer performed in it's vehicle sound lab) The Average person does not perceive a doubling of volume until in the 8-10 dB gain area.
What that means as far as power goes is this: You would need roughly 9 dB gain to "Hear" something twice as loud. That means you almost need to quadruple the output to perceive the volume to be twice as loud. 1-2 dB was the amount needed to Hear a change in volume. (roughly a 2dB value there)
So, the 1 sub at 500 watts would need to become 8 subs (62.5 w per sub or 500w total) to be "Twice as Loud" or go from 1 sub 500w to 1 sub 4000w. Remember this: For every 3 dB gain, you have to DOUBLE the value before it.
Here's a quick example: 1-2-4-8 or 2-4-8-16.
There are other factors to be concerned with on how to maximise the effectiveness of a set-up (Minimizing cancelations) but I'd throw this out to you guy's to chew on. There are also alot of other smaller details to know to get the most out of a set-up. Hell, porting a sub and firing it in the right direction can net measured gains up to 10 dB.
Final thing (since I don't get a chance to get on the net much) is this: It's all about the installation, not the individual parts. Same thing apply's to building our cars.
Last edited by Richiec77; 01-22-2006 at 09:30 AM.
02-17-2006, 11:16 PM
#13
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Run 2 speakers. Why does anyone run fifteens over twelves, besides the different type of bass that is produced, there is more surface area. And that is what you are looking for. You are trying to move as much air as possible. Forget all the technicle stuff posted earlier. You dont have to be a genius. The more air you move, the more bass. And if you dont believe that, then you need to check out Kickers square speaker. They designed it because it has more surface area than a round speaker. Bottom line, the more the merrier!
02-18-2006, 10:19 AM
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Originally Posted by macdaddyZ28
Run 2 speakers. Why does anyone run fifteens over twelves, besides the different type of bass that is produced, there is more surface area. And that is what you are looking for. You are trying to move as much air as possible. Forget all the technicle stuff posted earlier. You dont have to be a genius. The more air you move, the more bass. And if you dont believe that, then you need to check out Kickers square speaker. They designed it because it has more surface area than a round speaker. Bottom line, the more the merrier!
Look at the 12" Brahma, it's got like 28 mm of one way linear xmax and if you take the surface area into account and compare it to a 15 then the 15 looks like it will win but if the 15 only has like 10 mm of one way linear xmax then you can start to compare them. Plenty of details are still needed to compare them (box configuration, speaker specs, are they in the same car etc...) Just giving giving my $.02 on it.
Ted
