the12volt.com spacer
the12volt.com spacer
the12volt.com spacer
the12volt.com spacer
icon

adding one more sub, noticeable difference?


Post ReplyPost New Topic
< Prev Topic Next Topic >
jeffchilcott 
Platinum - Posts: 2,483
Platinum spacespace
Joined: April 11, 2002
Location: United States
Posted: April 07, 2007 at 12:48 AM / IP Logged  
no prob, and the setup did maintain output on all the amps, as I increased the setups I was required to up the # of batteries in the setup as well, to maintain voltage, mainly so the amps wouldnt shut off in just a 3 second burp!
again just thought I would throw in some of my results, maybe if Im bored tomorrow I will do a test of 2 subs in our daily driver.   same enclosure, with one amp on them.   Just maybe I will throw 2 on and look at the DB increase across the board with an absolute doubling of power, if the charging system will support it!
2009 0-1000 Trunk WR 154.0DB 2009 1001+ Trunk WR
2007 USACI World Champion
2007 World Record
2006 USACI Finals 2nd Place
stevdart 
Platinum - Posts: 5,816
Platinum spaceThis member has made a donation to the12volt.com. Click here for more info.spaceThis member has been recognized as an authority in Mobile Audio and Video. Click here for more info.spaceThis member consistently provides reliable informationspace
Joined: January 24, 2004
Location: Pennsylvania, United States
Posted: April 07, 2007 at 3:58 AM / IP Logged  

Jeff, glad you gave input.  I'd be willing to bet a that there could be a truer and more realizeable db increase at the lowest level...1 sub to two with double power...than it could be when you are up into the comp extremes.  At your high comp levels, the difference is more measureable than it is "noticeable", and probably less of an increase, wouldn't you say?  My thinking here is that at the lowest level like this thread deals with, there would be less environmental limitations to the SPL increase that would come into play.  Windshields pulsing and those kinds of things.

And, again, while this thread has grown to unreadable proportions and the OP has long ago left the building, I just wanted to clarify in my own mind what the physics were behind "doubling of cone area" and its effect on SPL.  When I can make some tiny progress in beginning to understand the enormously complex relationship of forces that combine to make sound, I know I've learned something.   Logarithmic math hurts my head!

custom_audio_ny wrote:
apparently we all got way off course.

That's okay.  Some of us like a good argument from time to time.

Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
jeffchilcott 
Platinum - Posts: 2,483
Platinum spacespace
Joined: April 11, 2002
Location: United States
Posted: April 07, 2007 at 9:44 AM / IP Logged  
To me at this point in time, I can tell the diffrence from a low 150 to a high 150, and normally can tell withen .5DB where something is from 155-159.    I spent alot of time testing there and and very use to the pressures and how volient it gets.
Anything above a 157 is very violent, 160-165 range is something that is an experience all in it self.
I have been in one vehicle now that was capable of doing 166DB on the dash with the vehicle sealed up, the way that the whole floor and everything in the vehicle flexes is something that I can barely describe!
I know alot of people understand that the +3db secenario is in an optimum situation, but sometimes you get more do to airflow, sometimes less because of that constriction.    
Just thought I would chime in to provide some insite and testing that I have done, as that is what I am here for!
2009 0-1000 Trunk WR 154.0DB 2009 1001+ Trunk WR
2007 USACI World Champion
2007 World Record
2006 USACI Finals 2nd Place
custom audio ny 
Copper - Posts: 176
Copper spacespace
Joined: March 11, 2007
Location: United States
Posted: April 07, 2007 at 10:47 AM / IP Logged  

Yes stevdart, a good argument is refreshing..as well as a debate where the participants really know thier stuff. It seems there is an endless amount of material to learn on this subject..as well as the field in gerneral.

As far as what you wrote in your last post "I just wanted to clarify in my own mind what the physics were behind "doubling of cone area" and its effect on SPL" do you feel we have found a conclusive answer?...or will only a percise lab experiment satisfy the topic?

As for myself, I feel satisfied in a general sense. I know there are endless variables that can effect "measured" output but the theoretical answer seems correct.

With all else being equal in a perfect environment..this is what I conclude......

Doubling the number of speakers (I am more comfortable with that terminology over "cone area"..just me) using a correlated "sound" and the identical power to each speaker should a theoretical 6dB increase....uncorrelated yields a 3dB increase.

If the power is halved and an addtional speaker is added....this should yield a theoretical 3dB if correlated...no increase if uncorrelated.

For now I would appreciate some opinions for the above situations without getting Einstein on us. If adding 2 or more dB's of different value I would need a program..I also get brain melt when dealing with logarithems on paper..I am done with school..lol. But since we are only dealing with 2 equal numbers..we only need to agree on how they add correlated and uncorrelated and put the physics aside.

Thanks again everyone for contributing and impressing me.

Custom Audio
Lynbrook NY
ASE/MECP master certified
stevdart 
Platinum - Posts: 5,816
Platinum spaceThis member has made a donation to the12volt.com. Click here for more info.spaceThis member has been recognized as an authority in Mobile Audio and Video. Click here for more info.spaceThis member consistently provides reliable informationspace
Joined: January 24, 2004
Location: Pennsylvania, United States
Posted: April 07, 2007 at 11:11 AM / IP Logged  

Didn't you already link to a caculator that adds uncorrelated values?

custom audio wrote:
do you feel we have found a conclusive answer?

I thought that I had clearly stated in a previous post that I was satisfied with the information I found.

Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
custom audio ny 
Copper - Posts: 176
Copper spacespace
Joined: March 11, 2007
Location: United States
Posted: April 07, 2007 at 11:28 AM / IP Logged  

Yes I did stevdart..but it is not really needed when adding 2 equal outputs together..all you need to do (at least according to what I have been taught) is add 3db. And that is all the calculator does as well if the numbers are equal..its would come in handy for lets say..an  OSHA inspection. If you measured for example a drill press...an air tool and a racing engine individually..they would have different values..the calulator would certainly come in handy to determine the combined SPL, unless you enjoy tons of mind boggling mathematics and have plenty of free time (not to mention the great chance of error).

But there still seemed to be disagreement..well, I was emailed something to the effect "where did you get that goofy calculator?":..lol. well I guess we all learn things differently..hence the debate.

BTW I wanted thank jeff for taking the time to do these tests. Keep posting results..maybe they will prove these theroies conclusivly. I would stick to much lower power levels however, for the sake of this discussion. This will help with any inaccuracies due to body flex, current draw and a host of other issues. The amount of things you need to deal with to bring 157+db to 160+db is much more then required to prove this theory.

Custom Audio
Lynbrook NY
ASE/MECP master certified
jeffchilcott 
Platinum - Posts: 2,483
Platinum spacespace
Joined: April 11, 2002
Location: United States
Posted: April 07, 2007 at 10:41 PM / IP Logged  
I will do, I just got home from apartment shopping. If I have some time tomorrow and its nice out I will be testing some things
2009 0-1000 Trunk WR 154.0DB 2009 1001+ Trunk WR
2007 USACI World Champion
2007 World Record
2006 USACI Finals 2nd Place
Page of 7

Sorry, you can NOT post a reply.
This topic is closed.

  Printable version Printable version Post ReplyPost New Topic
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot delete your posts in this forum
You cannot edit your posts in this forum
You cannot create polls in this forum
You cannot vote in polls in this forum

  •  
Search the12volt.com
Follow the12volt.com Follow the12volt.com on Facebook
Friday, March 29, 2024 • Copyright © 1999-2024 the12volt.com, All Rights Reserved Privacy Policy & Use of Cookies
Disclaimer: *All information on this site ( the12volt.com ) is provided "as is" without any warranty of any kind, either expressed or implied, including but not limited to fitness for a particular use. Any user assumes the entire risk as to the accuracy and use of this information. Please verify all wire colors and diagrams before applying any information.

Secured by Sectigo
the12volt.com spacer
the12volt.com spacer
the12volt.com spacer
Support the12volt.com
Top
the12volt.com spacer
the12volt.com spacer