tpg Posted June 11, 2002 Share Posted June 11, 2002 . Quote Link to comment Share on other sites More sharing options...
justin_tx_16 Posted June 11, 2002 Share Posted June 11, 2002 no. you have to find the sound intensity level, add that and figure from there, convert it back to dB. it is not just add up the dB rating. it involves logorithms... grrrrrrrrrr ------------------ -justin SoundWise Support A technical help site created by me and my fellow Klipschers I am an amateur, if it is professional; ProMedia help you want email Amy or call her @ 1-888-554-5665 or for an RA# 800-554-7724 ext 5 Klipsch Home Audio help you want, email support@klipsch.com or call @ 1-800-KLIPSCH RA# Fax Number=317-860-9140 / Parts Department Fax Number=317-860-9150s> Quote Link to comment Share on other sites More sharing options...
boa12 Posted June 11, 2002 Share Posted June 11, 2002 i'd say it's more of an average & probably somewhat more or less depending on reinforcement/cancellation. me i'd add the 3 figures & divide by 3 & be done w/ it. ------------------ My Home Systems Page Quote Link to comment Share on other sites More sharing options...
tpg Posted June 11, 2002 Author Share Posted June 11, 2002 . Quote Link to comment Share on other sites More sharing options...
ShapeShifter Posted June 11, 2002 Share Posted June 11, 2002 Just wait until your significant other asks; Is that a new doohickey?...Whaaat?...You know....The one sitting on the little thingamajig. I tell my GF, I've never bought a doohickey in my life. Oooops! I usually wish I could bring those words back. ------------------ KLIPSCH IS MUSICf> My Systems f>s>c> This message has been edited by ShapeShifter on 06-11-2002 at 06:10 PM Quote Link to comment Share on other sites More sharing options...
justin_tx_16 Posted June 11, 2002 Share Posted June 11, 2002 I will do the figuring for you. just FWIW... if you had a 112dB and 113dB speaker playing together, the max SPL is 115.5dB. so you can get somewhat of an idea from that, till i figure the current situation you have here ------------------ -justin SoundWise Support A technical help site created by me and my fellow Klipschers I am an amateur, if it is professional; ProMedia help you want email Amy or call her @ 1-888-554-5665 or for an RA# 800-554-7724 ext 5 Klipsch Home Audio help you want, email support@klipsch.com or call @ 1-800-KLIPSCH RA# Fax Number=317-860-9140 / Parts Department Fax Number=317-860-9150s> Quote Link to comment Share on other sites More sharing options...
justin_tx_16 Posted June 11, 2002 Share Posted June 11, 2002 here are the steps (oh how i love to teach physics!) you need to first get a bel. no not a trip to wal-mart. bel = B B=log db/reference level the reference level is 10^-12 watt/m^2 dB (really a dBl) = 0.1 bel bel = 10 dB dBl=10 log Lpt = 10 log10 so, lets figure this... note, the log-1 means it is not a natural log, but a log sub -1 who wants to figure this out? not me haha, i wrote the equation, you're going to answer it. ------------------ -justin SoundWise Support A technical help site created by me and my fellow Klipschers I am an amateur, if it is professional; ProMedia help you want email Amy or call her @ 1-888-554-5665 or for an RA# 800-554-7724 ext 5 Klipsch Home Audio help you want, email support@klipsch.com or call @ 1-800-KLIPSCH RA# Fax Number=317-860-9140 / Parts Department Fax Number=317-860-9150s> Quote Link to comment Share on other sites More sharing options...
tpg Posted June 11, 2002 Author Share Posted June 11, 2002 . Quote Link to comment Share on other sites More sharing options...
justin_tx_16 Posted June 11, 2002 Share Posted June 11, 2002 quote: Originally posted by trespasser_guy: Umm, any phsics teachers in the house?! I haven't had physics, so, I am not even gonna try this.... did not say it was going to be easy RAY GARRISON!!! WE NEED YOU ------------------ -justin SoundWise Support A technical help site created by me and my fellow Klipschers I am an amateur, if it is professional; ProMedia help you want email Amy or call her @ 1-888-554-5665 or for an RA# 800-554-7724 ext 5 Klipsch Home Audio help you want, email support@klipsch.com or call @ 1-800-KLIPSCH RA# Fax Number=317-860-9140 / Parts Department Fax Number=317-860-9150s> Quote Link to comment Share on other sites More sharing options...
Soundthought Posted June 11, 2002 Share Posted June 11, 2002 Logarithms aren't too bad. Evething else after that is. And I mean everything. Huh.. What..Yep...True. I know not of which i speak. This message has been edited by Audioreality on 06-13-2002 at 10:19 PM Quote Link to comment Share on other sites More sharing options...
cluless Posted June 11, 2002 Share Posted June 11, 2002 Yes, I did pick the ever-dreaded chartruse flompy doodle guy for this post... First we must get rid of all of those logs http://www.redroo.com.au/ms50.html which reduces the equation to mulch! and we must remember the equation may say Pi(r-squared)...but in reality we all know...Pie are round...cake are square.. what's purple and commutes...the abelian grape...math humor...what can you say... and now the little flompy doodle guy..shakes out green turns red. This is not a good sine. This message has been edited by cluless on 06-11-2002 at 08:58 PM Quote Link to comment Share on other sites More sharing options...
WMcD Posted June 11, 2002 Share Posted June 11, 2002 Roughly speaking, if you double the number of random noise sources, you get 3 dB gain. If the signal is in phase and the speakers are closely spaced, you get 6 dB gain. This is a joker in the the pack. Let's assume the signal is random. You're starting at about a base line of 115 dB for one speaker. Going to two gives you 118 dB. Doubling to four gets you to 121 dB. We'll throw in another 2 dB for the additional speaker and giving some honor to the higher efficency of the system as a whole. So you're talking 123 dB at best. That was my initial calculation in my head. It doesn't quite make sense since the two mains at 120 dB would give that alone. But please consider that the surrounds and center are putting out less power than the mains. ----- This is after some edits. A more sophisticated calulation is that a decibel is a 1/10 of a Bell, named for Alexander Graham. So for any given dB we're actually raising 10 to the power of 1/10 Bell and winding up with a raw number which can be added. Then converted back to Bell by the anti log, and multiply by 10 to get decibel, or dB. So, 120 dB has a level of 10^12.0 = 1.0E12. Ya see, we just moved the decimal point. For 115 dB we have a level of 10^11.5 = 3.2E11 (do this with a calculator) For 113 dB we have a level of 10^11.3 = 2.0E11 Giving the weighting for two speakers, when they're present, the raw total is 2.7E12 or: 1.0E12 1.0E12 3.2E11 2.0E11 2.0E11 ----- 2.7E12 Taking the common log of 2.7E12 , we find 12.4 Bell or 124 dB. Moved the decimal point. - - - - Oh, you ask, what is this anti log stuff? It just answers a question. If 10^? = 2.7E12 or 2.7 x 10^12, what is the ?. -- - - Now, you should ask, does this make sense? Lets try adding the two 120 dB sources. According to the rule, the intensity in Bell is 12. That is 10^12. or 1,000,000,000,000. If there are two of them, we get 2,000,000,000,000. or 2.0 E 12. Take the common log of 2.0 E 12 and we get 12.301 Bell. or 123.01 deci-Bell. You see, there was a 3 dB increase by adding the two souces in raw numbers. That is what I think. Gil This message has been edited by William F. Gil McDermott on 06-11-2002 at 10:07 PM Quote Link to comment Share on other sites More sharing options...
Soundthought Posted June 11, 2002 Share Posted June 11, 2002 Ahhh....I see.... Cake R square. It's all very clear now. I know what i must do... Thanks for the breakdown Gil. This message has been edited by Audioreality on 06-13-2002 at 10:05 PM Quote Link to comment Share on other sites More sharing options...
cluless Posted June 11, 2002 Share Posted June 11, 2002 So now we are adding up speaker outputs...and averaging...now what if they are on separate loops...are we going into Kirchoff Laws(Okay that Russian guy- I cant spell)..and suppose that you have all of your speakers running directly off your reciever(parallel)...how does that affect your power as opposed as feeding one speaker (in series)...I'm just....kidding...and combining physics and psychosis..TTFN and ...now I lay me down to sleep...I pray "I don't wake up a creep"... Quote Link to comment Share on other sites More sharing options...
BBB Posted June 11, 2002 Share Posted June 11, 2002 Tsk..Tsk..TskAnd someone here was saying they were worried about ME. I dont remember exactly what he said. Something about tree lights and hand clapping. Wait a minute . Its coming to me. Man O man my memory stinks ! It will dawn on me in a second. Im pretty sure its the same person that wanted to use the Klipsch Forum for Solid Gold Dancer auditions . Wow ! .The name should just JUMP right out at me. Oh well. I better go before that same guy catches me monkeying around again. Now where did I put that bottle of Dramamine ? Quote Link to comment Share on other sites More sharing options...
cluless Posted June 12, 2002 Share Posted June 12, 2002 BBB- Here drink this \~/ ...Everything will be juuusssst fiiiinnnne Quote Link to comment Share on other sites More sharing options...
Ray Garrison Posted June 12, 2002 Share Posted June 12, 2002 trespasser_guy, this is actually a pretty easy question. There is absolutely no way to answer that question from a theoretical perspective with any degree of precision and accuracy unless (a) you provide the exact dimensions of the room, ( you have a room that is very easy to model (ie, empty, solid walls, regular proportions, no major openings), © you specify *EXACTLY* where each of the speakers is, (d) you specify *EXACTLY* were the listening position is, (e) you specify the frequency at which you're evaluating this, and (f) you have a friend who knows a lot of physics. Gil's exercise is interesting from a theoretical standpoint, but I bet if you set the stuff up and measured the SPL you'd find your actual results would, er, vary somewhat. ------------------ Music is art Audio is engineering Ray's Music System Quote Link to comment Share on other sites More sharing options...
lne937s Posted June 12, 2002 Share Posted June 12, 2002 An exact figure is difficult to find. However, in general, figure a 3db gain for each doubling of output sources of equal output. figure 2-2.5db for the third. You can use complex equations to figure the exact output in ideal circumstances, but listening room parameters will throw this off. It is difficult for the human ear to hear fractions of a decimal. So, unless you're a perfectionist or engineer, don't worry about it. The best way to figure it out is to buy a cheap SPL meter from Radio Shack and measure it in your room at the listening position. Yes, you could do math all day to compensate for positioning of speakers, room parameters, resonance and sound absorbsion properties of the materials used in the room's construction, etc. However, if you went to work and earned money with that time, you could buy the meter and have money left over to buy music. Also the SPL meter is good for measuring adjustments to your system. good luck Larry Quote Link to comment Share on other sites More sharing options...
kenratboy Posted June 12, 2002 Share Posted June 12, 2002 If I has L33T programming skills, I would make a progie for the Ti-83 and Ti-89 (mine) However, I have no mad programming skilld, so forget it. I am sure a few people on this site know how, get to work! ------------------ Receiver: Sony STR-DE675 CD player: Sony CDP-CX300 Turntable: Technics SL-J3 with Audio-Technica TR485U Speakers: JBL HLS-610 Subwoofer: JBL 4648A-8 Sub amp: Parts Express 180 watt Center/surrounds: Teac 3-way bookshelfs Yes, it sucks, but better to come. KLIPSCH soon! My computer is better than my stereo! Quote Link to comment Share on other sites More sharing options...
boa12 Posted June 12, 2002 Share Posted June 12, 2002 could always do it w/ progressive testing & a sound meter & test tones. 2 speakers - level. add center - level. add surrounds - level. ------------------ My Home Systems Page Quote Link to comment Share on other sites More sharing options...
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