Objective calculations for increasing sub stage output (not a question)


Jakerrr

Senior VIP Member
Dec 4, 2011
371
1
Lexington, SC
for my personal use

(weighing options and considering a loud future system with the limited space I have)

but I figured I might as well share it

doubt anyone will get any use out of this but a few may find it interesting

SA

6 8's fed >4800w : ~2.45 X SPL of 1 SA-15 on 1200w

3 10's >3600w 1.89

2 12's >2400w 1.50

sq root of (product of cone-area and power ratios) = SPL ratio

SPL ratio of 2 (X2 SPL of original system) = 2*(sq rt of 10) dB = ~6.32 dB gain

obvious "in a perfect world" and "all else equal" assumptions made

but measures were taken to decrease likelihood of "overshooting" the ratios

the classic definition of SPL is the one referred to in this model

that is, sound pressure in Pascals/PSI/etc

a ~6.32 dB gain corresponds to pressure (or voltage, albeit with a mythical zero resistance rise) increasing by factor of 2

 

adulbrich

Lock up your daughters!
May 11, 2014
14,015
0
Ames, Iowa
Wat?

Too much math.

Step one: Get beast subs

Step two: Throw 37 jiggawatts of power at them

Step three: Enjoy your SPL's //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 
OP
Jakerrr

Jakerrr

Senior VIP Member
Dec 4, 2011
371
1
Lexington, SC
Wat?
Too much math.

Step one: Get beast subs

Step two: Throw 37 jiggawatts of power at them

Step three: Enjoy your SPL's //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif
Like I said, this was just for my personal use. I'm a physics major and this stuff is pretty interesting to me and this in particular was pretty simple to figure out. I had it all on notepad and just copy pasted and added annotations. Thought it was kinda cool that 6 sa-8's on double rated power would generate 2 1/2 times the pressure of my current setup (1 sa-15 on double rated power before rise) theoretically. Also not many people seem to know that the theoretical 3 dB gain one gets from doubling power is actually sq.root(10) dB (~3.16).

 

adulbrich

Lock up your daughters!
May 11, 2014
14,015
0
Ames, Iowa
Yeah, you're not accounting for power compression though. The more power you try to feed a sub, the less you'll gain. Also, that's not talking about phase at all.

Less subs are better to reduce phase issues with large enclosures.

 

Jeffdachef

Gunz That Turn on Nunz
Feb 5, 2013
17,262
253
South Coast Metro, CA
Like I said, this was just for my personal use. I'm a physics major and this stuff is pretty interesting to me and this in particular was pretty simple to figure out. I had it all on notepad and just copy pasted and added annotations. Thought it was kinda cool that 6 sa-8's on double rated power would generate 2 1/2 times the pressure of my current setup (1 sa-15 on double rated power before rise) theoretically. Also not many people seem to know that the theoretical 3 dB gain one gets from doubling power is actually sq.root(10) dB (~3.16).
Estimated cone area of 6 8s is 301 in^2

Estimated cone area of 1 15 is 176 in^2

You have more cone area and cooling with the 8s Its not hard to win when you have one side completely stacked.

 

los33

Car Audio G
Apr 11, 2014
3,560
0
Houston, TX
Like I said, this was just for my personal use. I'm a physics major and this stuff is pretty interesting to me and this in particular was pretty simple to figure out. I had it all on notepad and just copy pasted and added annotations. Thought it was kinda cool that 6 sa-8's on double rated power would generate 2 1/2 times the pressure of my current setup (1 sa-15 on double rated power before rise) theoretically. Also not many people seem to know that the theoretical 3 dB gain one gets from doubling power is actually sq.root(10) dB (~3.16).
Is that so?

You just did an obvious post trying to prove how smart you think you are.

Just so you know you calculated a real world equation for cone area which depending on actual sub specs you can be louder on 500 more watts then the single 15.

Add in amp efficiency, amp power, box volume, port specs, size of cabin or car interior, frequency of box.

Maybe you would then be more considered a physics major...

//content.invisioncic.com/y282845/emoticons/applause.gif.bb805d8088f72dbc2fe808c29e85fb4c.gif

Sent from my draconis using Tapatalk

 

Jes 42

DeezNtzz
Aug 24, 2012
2,464
0
Ohio
//content.invisioncic.com/y282845/emoticons/lightning.gif.3313d59263b518d6d89ddcbfead237d0.gif

//content.invisioncic.com/y282845/emoticons/face2face.gif.c4346df91ccb89a430ef126c23624157.gif

 

adulbrich

Lock up your daughters!
May 11, 2014
14,015
0
Ames, Iowa
//content.invisioncic.com/y282845/emoticons/nerd.gif.c6fa51ddf7ff75f1c0371fbc648f70ae.gif//content.invisioncic.com/y282845/emoticons/slap.gif.87520e8ca8e90076ac30e777c0de5331.gif
 
OP
Jakerrr

Jakerrr

Senior VIP Member
Dec 4, 2011
371
1
Lexington, SC
Is that so?
You just did an obvious post trying to prove how smart you think you are.

Just so you know you calculated a real world equation for cone area which depending on actual sub specs you can be louder on 500 more watts then the single 15.

Add in amp efficiency, amp power, box volume, port specs, size of cabin or car interior, frequency of box.

Maybe you would then be more considered a physics major...

//content.invisioncic.com/y282845/emoticons/applause.gif.bb805d8088f72dbc2fe808c29e85fb4c.gif

Sent from my draconis using Tapatalk
See: 'obvious "in a perfect world" and "all else equal" assumptions made' Surely you didn't think I was making a real world calculation. Especially with multiple disclaimers that blatantly indicate that it was approximate AND theoretical

And in regard to the proving I'm smart thing. I kind of figured there would be that one immature person that "does an obvious post to prove how socially superior they think they are"

I'm going to give you the benefit of the doubt and assume you just didn't read the post in its entirety and do you the kindness of not using a clapping emoji

 

adulbrich

Lock up your daughters!
May 11, 2014
14,015
0
Ames, Iowa
Elaborate on these, please?
If you were serious:

As you try to feed a coil more power, it heats up. This causes the impedance to rise and is *one of* the factors that causes impedance rise. Higher impedance creates more heat, which creates higher impedance... and just keeps going up as you add power. I'm sure I'm forgetting something important with this explanation, but I'm sure someone else on the internet will jump in and correct me.

With phase issues, it gets complicated. There is more cancellation when you have more drivers. Have you heard of active noise cancelling headphones? the drivers produce a sound wave exactly inverse the one that the microphone picks up. This pretty much negates it and the noise you hear is far less audible. It's late and I just got home from a 9 hour shift, so pardon me if I didn't do a fantastic job explaining things

 
OP
Jakerrr

Jakerrr

Senior VIP Member
Dec 4, 2011
371
1
Lexington, SC
Elaborate on these, please?
Drivers should be spaced close to each other if you want as much efficiency gain from increased cone area as possible. Only a single driver is perfectly coupled. And he was also referring to power compression or non linearity. It was adulbrich's post so if he wants to elaborate he can do so

nvm he did

 

los33

Car Audio G
Apr 11, 2014
3,560
0
Houston, TX
See: 'obvious "in a perfect world" and "all else equal" assumptions made' Surely you didn't think I was making a real world calculation. Especially with multiple disclaimers that blatantly indicate that it was approximate AND theoretical
And in regard to the proving I'm smart thing. I kind of figured there would be that one immature person that "does an obvious post to prove how socially superior they think they are"

I'm going to give you the benefit of the doubt and assume you just didn't read the post in its entirety and do you the kindness of not using a clapping emoji
 

Socially superior in what? Being a super genius of subs and how they work.

 

Im no immature user, im just bored.

 

Whether it be theoretical or approximate or even an estimation.. You came in feeling proud and now you are discouraged due to not knowing what is publicly and entirely overwhelmingly explained all over the internet.

 

Like the franks red hot old lady says "i put that sh1t on everything"

 

Sent from my draconis using Tapatalk

 
OP
Jakerrr

Jakerrr

Senior VIP Member
Dec 4, 2011
371
1
Lexington, SC
Estimated cone area of 6 8s is 301 in^2
Estimated cone area of 1 15 is 176 in^2

You have more cone area and cooling with the 8s Its not hard to win when you have one side completely stacked.
These were just different configurations that I can fit in my small trunk. The 8's (or any smaller sub) have comparatively small sized enclosure requirements per unit of cone area, which offsets the decrease in efficiency compared to one big driver that is perfectly coupled.

 
OP
Jakerrr

Jakerrr

Senior VIP Member
Dec 4, 2011
371
1
Lexington, SC
Socially superior in what? Being a super genius of subs and how they work.
Im no immature user, im just bored.

Whether it be theoretical or approximate or even an estimation.. You came in feeling proud and now you are discouraged due to not knowing what is publicly and entirely overwhelmingly explained all over the internet.

Like the franks red hot old lady says "i put that sh1t on everything"

Sent from my draconis using Tapatalk
I don't think I explained anything that people on here that people wouldn't be able to easily find out elsewhere if they so pleased, but the point of these 3 comparisons were for ME and my actual system and the system I am building in the future. I was seeing what all I could fit of each size of the SA series (sticking with the series I know best) and just in case somebody didn't know what all of it meant, I explained it. I shared it considering I actually had it typed on notepad. It seemed more beneficial to share than doing nothing at all with it.

Came in feeling proud? Really?

Like Randall from Clerks says "there's nothing more exhilarating than pointing out the shortcomings of others is there?"

 

los33

Car Audio G
Apr 11, 2014
3,560
0
Houston, TX
I don't think I explained anything that people on here that people wouldn't be able to easily find out elsewhere if they so pleased, but the point of these 3 comparisons were for ME and my actual system and the system I am building in the future. I was seeing what all I could fit of each size of the SA series (sticking with the series I know best) and just in case somebody didn't know what all of it meant, I explained it. I shared it considering I actually had it typed on notepad. It seemed more beneficial to share than doing nothing at all with it.
Came in feeling proud? Really?

Like Randall from Clerks says "there's nothing more exhilarating than pointing out the shortcomings of others is there?"
Drama queen..

Sent from my draconis using Tapatalk

 

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