Power vs. quantity?

[Inertia]

If you took 2 of the same subs and put them them in like enclosures with say 500watts each. Would this produce more SPL than a single one of these subs with with double the power (1,000watts) going to it. Or would the output be the same??

 

[j_garcia]

Two drivers have twice the radiating area. One driver with twice the individual power can't make up for that.

 

[highfigh]

If you took 2 of the same subs and put them them in like enclosures with say 500watts each. Would this produce more SPL than a single one of these subs with with double the power (1,000watts) going to it. Or would the output be the same??

Throwing a ton of power at one speaker causes the voice coil to heat up and when a conductor gets hotter, the resistance increases. This causes what's called 'thermal compression' and it can actually sound like less power is being applied. Adding one speaker in series causes the impedance to double but since the radiating area has doubled, the net effect is 0dB lost/gained. If you were to use two drivers with twice the impedance/voice coil and wired them parallel, you would gain 3dB. The impedance and electrical power applied is the same but yuo would gain from the second cone's output. If you wire two drivers with the same impedance as the original one, the impedance is cut in half and that doubles the power, which results in a 3dB gain. With the additional output of the second driver adding another 3dB, your net gain is 6dB and that's equivalent to quadrupling the power to a single driver.

 

[darien87]

Throwing a ton of power at one speaker causes the voice coil to heat up and when a conductor gets hotter, the resistance increases. This causes what's called 'thermal compression' and it can actually sound like less power is being applied. Adding one speaker in series causes the impedance to double but since the radiating area has doubled, the net effect is 0dB lost/gained. If you were to use two drivers with twice the impedance/voice coil and wired them parallel, you would gain 3dB. The impedance and electrical power applied is the same but yuo would gain from the second cone's output. If you wire two drivers with the same impedance as the original one, the impedance is cut in half and that doubles the power, which results in a 3dB gain. With the additional output of the second driver adding another 3dB, your net gain is 6dB and that's equivalent to quadrupling the power to a single driver.

I think I just had a tiny stroke.

 

[j_garcia]

Two drivers in the same undivided enclosure playing the same thing will only yeild +2dB. Two separate enclosures would give you +6dB.

 

[gmichael]

Someone is bound to say this eventually. It may as well be me.
There is no replacement for displacement.

 

[rfolden]

Boom! (Pow?)

Someone is bound to say this eventually. It may as well be me.
There is no replacement for displacement.

Which is why I suggest two subs, each in a separate enclusure. One sub "per front channel", placed near enough to each main listening speaker as applicable. Start at 15" diameter and head to as large as the room can bear or your wallet can afford. If you're worried about port noise, choose a sealed enclosure design. If you're worried about ruining the stereo image, get some active equalization ( and perhaps some MASSIVE outboard amplification?) to keep only the lowest frequencies produced by los subbos (oops, sorry: altavoz pour sonidos muy graves). And of course, make sure you can cut those subs off right quick like if you don't like what they add to a conventional (2.0) listening session.

Marky-Mark Sez:

"Can you feel it, baby?"

πr²? NO! πr round

 

[lsiberian]

Which is why I suggest two subs, each in a separate enclusure. One sub "per front channel", placed near enough to each main listening speaker as applicable. Start at 15" diameter and head to as large as the room can bear or your wallet can afford. If you're worried about port noise, choose a sealed enclosure design. If you're worried about ruining the stereo image, get some active equalization ( and perhaps some MASSIVE outboard amplification?) to keep only the lowest frequencies produced by los subbos (oops, sorry: altavoz pour sonidos muy graves). And of course, make sure you can cut those subs off right quick like if you don't like what they add to a conventional (2.0) listening session.

Marky-Mark Sez:

"Can you feel it, baby?"

πr²? NO! πr round

This is not what Dr. Floyd E. Toole from harman audio suggests. Since LFE is non directional in a rectangular room they modeled every conceivable placement scenario and the top 3 Were 4 mid wall on every wall, 4 one in each corner(great for corner loading), 2 mid wall on either the sides or front and back. This provides the smoothest response with the least amount of nulls at a listening position. You will only gain 3 db, but you will reduce peaks and nulls giving a better more realistic LFE experience. In fact the biggest issue in a setup with quality subs is the room modes which can be very nasty. 2 subs placed like this will do wonder for your experience. The above method would make sense if placement limitations or if you plan to have a high crossover for the subs.

 

[markw]

It's all about moving as much air as possible.

Once a speaker has reached it's maximum excursion, it's got no more to give. Simply throwing more power at it will simply burn out it's voice coil.

 

[lsiberian]

Once a speaker has reached it's maximum excursion, it's got no more to give. Simply throwing more power at it will simply burn out it's voice coil.

Well xmech and max rms are actually different deals altogether. One blows the woofer the other burns out the voice Coil.

 

[Warpdrv]

Once a speaker has reached it's maximum excursion, it's got no more to give. Simply throwing more power at it will simply burn out it's voice coil.

I believe his question was entertaining the thought that the driver could handle more then 1000w, and be underpowered at 500w. At least thats the way I would read it.

Adding Power - double the watts from 500 to 1000 will simply yield +3db from a single driver.

Adding driver same power will add +3b

Adding Drivers (considering they are the same - doubling drivers and doubling power)

This all depends on the room and 1/4 wavelengths how they will behave in room. Stacking the same driver in the same spot will yield +6db, doubling drivers and power. As soon as you separate them room modes and positive/negative coupling make the results unpredictable, and not the least bit linear with respect to frequency. You could get 6dB at some frequencies and lose 6dB at others. But if you're splitting them it's not for additional output, it's for better room response.

Outdoor uninhibited (no boundary's or ground plane) will gain you 6db


In my instance - I doubled drivers and power in each location - so I roughly gained 18db across the board but the room is certainly destructive towards the final measurement and output....

 

[markw]

Getting into semantics, are we?

Well xmech and max rms are actually different deals altogether. One blows the woofer the other burns out the voice Coil.

And, the end result (a dead driver) differs exactly how?

While they are two different parameters in speaker design, what I said is true. Think about it..

If you run out of xmax/xmech, why continue and go beyond the maximum power unless one is intent on blowing the voice coil?

One would hope that betweem xmax and xmech the distortion would become more obvious, no?

 

[Warpdrv]

And, the end result (a dead driver) differs exactly how?

While they are two different parameters in speaker design, what I said is true. Think about it..

If you run out of xmax/xmech, why continue and go beyond the maximum power unless one is intent on blowing the voice coil?

One would hope that betweem xmax and xmech the distortion would become more obvious, no?

You def want to keep things in check, but there is no question that a HP filter and proper gain structure will be very important so you don't send a clipped signal to your amp - which can and will in many cases push the driver past linear excursion and into no mans land between xmax and xmech

 

[lsiberian]

And, the end result (a dead driver) differs exactly how?

While they are two different parameters in speaker design, what I said is true. Think about it..

If you run out of xmax/xmech, why continue and go beyond the maximum power unless one is intent on blowing the voice coil?

One would hope that betweem xmax and xmech the distortion would become more obvious, no?

You can recone an xmech exceeded driver in most cases. Replacing a Voice Coil is normally much tougher unless it's a TC driver with swappable VCs.

But blowing the cone usually comes from bottoming out and that often can occur as a result of clipping in which an amp starts to act like a squarish wave resulting in a very high apparent power. Clipping also sounds terrible so providing adequate power reserves with the appropriate high pass filter is the standard recommendation. Still multiple driver setups are preferred.

 

[markw]

You can recone an xmech exceeded driver in most cases. Replacing a Voice Coil is normally much tougher unless it's a TC driver with swappable VCs.

Well, you can repair anything if you're willing to spend enough money.

But blowing the cone usually[/] comes from bottoming out and that often can occur as a result of clipping in which an amp starts to act like a squarish wave resulting in a very high apparent power.

So, you're saying a speaker CAN be overdriven into the physical danger zone if enough power is applied? That I agree with. In fact, I think I said it already.

Clipping also sounds terrible so providing adequate power reserves with the appropriate high pass filter is the standard recommendation.

Wasn't this brought up previously? But, that's different than simply applying more raw power, isn't it?

Still multiple driver setups are preferred.

Agreed. I think myself and several others either plainly stated or implied it to begin with. So, why all the mental masturbation in the first place? All it did was muddy the waters.

 

[highfigh]

Two drivers in the same undivided enclosure playing the same thing will only yeild +2dB. Two separate enclosures would give you +6dB.

But if the enclosure is made for two drivers, it yields the same increase. If you were to put two drivers in the enclosure for one, the F3 will go way up because it's not the correct enclosure.

 

[highfigh]

And, the end result (a dead driver) differs exactly how?

One smells bad and the other looks bad.

 

[highfigh]

You can recone an xmech exceeded driver in most cases. Replacing a Voice Coil is normally much tougher unless it's a TC driver with swappable VCs.

But blowing the cone usually comes from bottoming out and that often can occur as a result of clipping in which an amp starts to act like a squarish wave resulting in a very high apparent power. Clipping also sounds terrible so providing adequate power reserves with the appropriate high pass filter is the standard recommendation. Still multiple driver setups are preferred.

Re: voice coils that suffer from excessive heat- I have a pair of Altec 417B instrument/PA drivers and I used to use one for my guitar with a Gallien-Krueger guitar amp that's rated at 250W into a 4 Ohm load. I loaned it to the bar I worked for when they wanted to play music out to the street when the Al McGuire's Run was going on. The amp occasionally had a high frequency oscillation and I could get it to stop by banging on the top. Well, sure enough, it happened that day. My friend said it was cranking along just fine and suddenly, it started to sound really weird, got quieter and then stopped completely. When I got it back, the cone was frozen in place. Since I knew it was toast, I cut the edge of the cone and started pulling it out. The coil released at the top and started unwinding from the VC former. The enamel had melted and when that happens, it becomes a really good glue. I took it in and had it re-coned.

 

[Warpdrv]

One smells bad and the other looks bad.

Hhahah very true....

I pushed a Mal-X with too much power and with that driver, the magnets are actually glued together - the heat generated from pushing it too hard melted the glue and they slid, voice coil was out of alignment giving that oh so nice scrapie scrapie sound....

 

[Seth=L]

Did you watch the video of the guy climbing the 1700ft tower?

http://www.youtube.com/watch?v=DTu0kZprj_4