4 18s in a wall, 94 astro

[GAM3OVR 5,000+ posts]

Now this thread is starting to deliver some funnies hahaha

i turned teh frown upside down lol

 

[PV Audio 5,000+ posts]

Thats all still a half-truth at best, concerning the "2-3db gain by just doubling power or cone area". Let alone adding more midrange:laugh:
One of the biggest problems on car audio forums is that people try to apply the dynamics from one environment within another. Classical horn theory, transfer theory, quarter-wave theory, standing wave theory, etc... I can see how this could happen, as just about every book and web site out there that tackles the dynamics of sound is written from a home audio / infinite environment perspective. Exporting these principles into contained environments (i.e. vehicle cabins) is kind of like attempting to build a flying machine on Mars by reading about the design principles behind the flying machines on Earth.

What I'd like to attempt here is to illustrate the problem with the theory that doubling your power results in a 3dB gain. This theory was never intended for low efficiency drivers, high gain environments, and high current applications. As most other theories mentioned above, this one has it's roots elsewhere. Think of infinite environment low current sound reproduction systems and 1 meter on-axis benchmarks where the first watt is always the most important watt... you may begin to see why this theory falls apart when applied to car audio.

Let's take a relatively inefficient woofer with a 1W sensitivity of 80dB and start doubling the power, each time resulting in a 3dB increase:

You see what's happening? By this principle, over a million watts would be required just to achieve 140dB. More importantly, take a look at the distinct curvature of the plot. Since the (W*2)=(dB+3) formula is fixed, so is the nature of the plot, no matter where we start in regard to power or efficiency.

But let's improve our odds by starting out with a subwoofer system that's a whopping 100dB efficient at 1W:

We still need about sixteen thousand watts just to break 140dB (and well over a hundred thousand watts for an additional 10dB.) See the problem? Visually, we can isolate it to the vicinity of where the curve begins to bend into a near-flat line. Suffice it to say, this is an extremely misleading and erroneous way to look at the effects of power on the SPL product, especially once we've gone several orders beyond the magnitude of ~8, and even more so at the point where, mathematically, the gain to raw power ratio is virtually unchanging.

Is a lot to read, but it virtually elimnates all theories concerning the doubling affect:fyi:

While it's interesting to read, this science is not true in the slightest. A loudspeaker system still has the same fundamental theoretical rules regardless of the environment. How the system interacts with the environment, however, is where you can interject specifics like this. You're using the sensitivity rating to make your argument when the sensitivity has nothing to do with the discussion. It is merely a measure of the driver's projected efficiency, nothing more. It can NOT be used to determine how loud the speaker is or how it will behave under different power loads.

So while your information is nice, it is unfortunately not true. It has been proven for decades that a double in input power nets you a 3db gain which in mathematical terms is twice as loud. In human terms, it's only slightly louder and it takes 10x the amplifier power to make a subjective doubling in loudness.

 

[TnT_Sounds 10+ year member]

While it's interesting to read, this science is not true in the slightest. A loudspeaker system still has the same fundamental theoretical rules regardless of the environment. How the system interacts with the environment, however, is where you can interject specifics like this. You're using the sensitivity rating to make your argument when the sensitivity has nothing to do with the discussion. It is merely a measure of the driver's projected efficiency, nothing more. It can NOT be used to determine how loud the speaker is or how it will behave under different power loads.
So while your information is nice, it is unfortunately not true. It has been proven for decades that a double in input power nets you a 3db gain which in mathematical terms is twice as loud. In human terms, it's only slightly louder and it takes 10x the amplifier power to make a subjective doubling in loudness.

Where and who has discovered all of this then? //content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

 

[Annnarbor84 5,000+ posts]

Put a fork in it, this thread is fucking done:wow:

 

[TnT_Sounds 10+ year member]

Put a fork in it, this thread is fucking done:wow:

yes, I need to stop bumping this.

And Fuck you hooker face

 

[CranberryYumYum 10+ year member]

bump

 

[Annnarbor84 5,000+ posts]

yes, I need to stop bumping this.
And Fuck you hooker face

Just so you know, when I get hard up for cash. I am coming for that coin in your avi, and I am pretty good with home invasions now. And after I rob you of your loot, I am going to make me a sammich to go

 

[PV Audio 5,000+ posts]

Where and who has discovered all of this then? //content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

Um, it has been known since the advent of dB meters. I don't know where you're getting off saying that a speaker with a 80dB sensitivity would take over a million watts of input power to reach 140dB when the sensitivity is probably the least important parameter when deciding numbers like that. The best SPL woofers out there have incredibly low sensitivities, and while it does take a lot of power to get them moving, that is due mainly to the mechanics behind the voice coil and the need for high thermal power handling. A home audio driver with the same sensitivity would cook under a fraction of the power than the SPL woofer would because of the different parameters. Sensitivity is not related to how loud the speaker can get; it is related to how efficient the speaker is.

http://knol.google.com/k/secrets-of-amplifier-and-speaker-power-requirements-revealed#

http://stereos.about.com/b/2008/08/09/audio-myth-doubling-amplifier-power-produces-twice-the-loudness.htm

http://www.ehow.com/how_2212599_set-up-power-amplifier.html

http://www.bittner-audio.com/default.php?page=pow2vol&l=en

 

[duece212 5,000+ posts]

I have nothing of value to add, but felt the need to post

ok, carry on

 

[TnT_Sounds 10+ year member]

Um, it has been known since the advent of dB meters. I don't know where you're getting off saying that a speaker with a 80dB sensitivity would take over a million watts of input power to reach 140dB when the sensitivity is probably the least important parameter when deciding numbers like that. The best SPL woofers out there have incredibly low sensitivities, and while it does take a lot of power to get them moving, that is due mainly to the mechanics behind the voice coil and the need for high thermal power handling. A home audio driver with the same sensitivity would cook under a fraction of the power than the SPL woofer would because of the different parameters. Sensitivity is not related to how loud the speaker can get.
http://knol.google.com/k/secrets-of-amplifier-and-speaker-power-requirements-revealed#

http://stereos.about.com/b/2008/08/09/audio-myth-doubling-amplifier-power-produces-twice-the-loudness.htm

http://www.ehow.com/how_2212599_set-up-power-amplifier.html

http://www.bittner-audio.com/default.php?page=pow2vol&l=en

I have seen more than a handful of people double their power and not see a 3db gain.

 

[TnT_Sounds 10+ year member]

Just so you know, when I get hard up for cash. I am coming for that coin in your avi, and I am pretty good with home invasions now. And after I rob you of your loot, I am going to make me a sammich to go

see you soon?

 

[Annnarbor84 5,000+ posts]

see you soon?

As soon as the funds are low

 

[PV Audio 5,000+ posts]

I have seen more than a handful of people double their power and not see a 3db gain.

As have I, my good man, which is why it's called theory. Regardless of the different hundreds of thousands of real world applications, the theory is still there and has been proven. If you double your input power in a hatchback like my civic, you'll probably get that 3dB gain. If you double your input power in a car like a big Merc which has the gas tank behind the seats and blocks nearly all noise, you definitely won't. Those are factors of the environment which are irrelevant when discussing the theory.

 

[TnT_Sounds 10+ year member]

Um, it has been known since the advent of dB meters. I don't know where you're getting off saying that a speaker with a 80dB sensitivity would take over a million watts of input power to reach 140dB when the sensitivity is probably the least important parameter when deciding numbers like that. The best SPL woofers out there have incredibly low sensitivities, and while it does take a lot of power to get them moving, that is due mainly to the mechanics behind the voice coil and the need for high thermal power handling. A home audio driver with the same sensitivity would cook under a fraction of the power than the SPL woofer would because of the different parameters. Sensitivity is not related to how loud the speaker can get; it is related to how efficient the speaker is.
http://knol.google.com/k/secrets-of-amplifier-and-speaker-power-requirements-revealed#

http://stereos.about.com/b/2008/08/09/audio-myth-doubling-amplifier-power-produces-twice-the-loudness.htm

http://www.ehow.com/how_2212599_set-up-power-amplifier.html

http://www.bittner-audio.com/default.php?page=pow2vol&l=en

Regardless; you can apply the +3dB upon doubled power at absolutely any starting point. So even if your woofer is seated in an efficient SPL enclosure that rates 100dB-50db @ 1W--as seen in the second example--this principle still falls on it's face once that curve begins to bend to the right.

 

[TnT_Sounds 10+ year member]

As have I, my good man, which is why it's called theory. Regardless of the different hundreds of thousands of real world applications, the theory is still there and has been proven. If you double your input power in a hatchback like my civic, you'll probably get that 3dB gain. If you double your input power in a car like a big Merc which has the gas tank behind the seats and blocks nearly all noise, you definitely won't. Those are factors of the environment which are irrelevant when discussing the theory.

My point exactly! The theory is merely just that, "a theory". As it may have worked for one doesn't mean it will work for everyone. Maybe in a perfect world.