Just because an audio setup looks cool, doesnt mean that it will sound good. While browsing through the forums here I have seen some pretty amazing setups with fiberglass enclosures. Very Impressive work you have all put into your cars. I am writing this up to help everyone who is inexperienced with car stereos to understand the whole idea behind acoustics and the way they work. Before getting any hate mail which I have also seen in my browsing, I would like to add that I am a certified Installer certifying institution being the CEA in Basic Electronics, Advanced Acoustics, Fiberglass Techniques, and Mobile Vide/Security/Navigation.
With that all on the table, here is the basic idea behind acoustics and why a setup with speakers going every direction is not ideal. When you have a setup where two or more speakers are not aimed in the same direction, you get
Deadened Noise also known as
Destructive Interference.
Before you can understand this you must understand how
sine waves work. A
sine wave is also known as a sound wave. it is measured by its
Wavelength,
Frequency.
Period, and
Amplitude.
Wavelength - Length in feet
Frequency - # of Cycles per second
Period - # of Seconds per Cycle
Amplitude - Peak
When
Sine Waves come together you either get
Constructive or
Destructive interference.
Constructive interference is when two or more sine waves build on eachother making a louder more apparent wave.
Destructive interference is where two sine waves cancel eachother out. See how in constructive interference, the sine waves are building on eachother whereas the destructive ones create the blue line which is flat. the flatter the sine wave, the less noise is made.
Basically the lesson is If you wan a really loud stereo with hard hitting bass, keep the speakers aimed in the same direction unless you know how to keep speakers in phase. Speakers out of phase also cause destructive intereference.
If anyone would like to know more about this or if any of you need help designing a system that will look good and sound good too, post a reply or hit me up on AIM, Screen name is in my profile my e-mail address is mobileinnovations05@yahoo.com.
so are you saying that my door speakers should be 180* out of phase with each other
please elaborate because I am confused as all hell right now.
scratches head. will not post will not post.
ToBoGgAn wrote:so are you saying that my door speakers should be 180* out of phase with each other
Balance the system to the left, to the right, then dead center. If you hear a lacking of bass or a muffled signal coming out when you balance to the center, they are out of phase. If not, then you are fine.
This post seems like it applies to speakers in the same or close enclosures, not across the car.
Sam
Ban low-performance cars, not high-performance ones.
ok kid where did you copy that from? Im assuming this is meant to be aimed at woofers. Bass is omnidirectional which means it travels in all directions equally. Ive seen woofers used in push pull configurations and they are pointed at each other. bandpass enclosures have woofers pointed at each other. We wont forget the inverse mounting of one woofer and the regualar mounting of the other woofer. yes the phasing has changed on it. also alot of SQ cars aim tweets off the windshield. The complete opposite direction of the listener. It is best to keep woofers on the same plane. but it is not always the case. tommy Mckinnie uses a power V with 12 woofers on each side facing each other and he can play music at almost 160 dbs. all day. It says in your profile that you are 17. Its good to try and learn and you wont be discouraged on here. There are alot of smart people on here and alot of us who have realized that book theories like the one you posted are not always correct and can not be applied to the real world. Step outside the box and put the book down. trial and error will teach you more than a book can any day.
very well put nate... a heIl of a lot nicer than anything that would have come outa my mouth on this topic
On the other hand....you have other fingers.
I just bought a 20 inch widescreen ultrasharp flat pannel..I'm going to have to subscribe to the high quality porn places now......damn
n8ball2013
Just to add:
Clamshell or isobaric enclosures which are the push/pull enclosures, Are great if you want an SQ setup.
This is essentially a sealed box with one subwoofer mounted inside and one subwoofer mounted outside, facing each other. This arrangement wont double your bass output just because your using 2 subs, BUT it will give you good bass response in a Physically smaller enclosure. When wiring up the 2 subs, its very important that one is wired in polarity and the other wired out of polarity. So they both travel in the same direction. Other wise, they will go Boom, and not in a good way.
isobaric enclosures aren't really that practical these days. Only really usefull if you just happen to have a ton of subs and not much space in your newly traded car, lol. or if you want to look cool, lol
--------------------------------------------------------------
Offical dealer for the following-
SOUNDSTREAM
DB LINK
DB DRIVE
PANASONIC
GARMIN
ROSEN
SCOSCHE
XE DESIGNS
SOUNDGATE
PAC
LITEGLOW
For the record, I have been a member of the org since I was 17. I am now 19 and am entertained by how you feel as though you are right because you are older. Now to explain my position completely, Your mentioned two walls of facing subwoofers, tell me where the microphone is set... Probably in the middle of the speakers. Sound pressure will be the highest where all of the speakers are meeting. Picture waves meeting at a central point. There is a lot of energy at that point. the subs are all moving towards a central target that being an SPL mic. For the arguement of me being wrong, go find some water and drop a rock into it. watch the ripples. Now drop two rocks in seperate places... Chaos no smooth ripples but confused ripples. the same with sound waves or sine waves. One side in the other is out. Now because I lost my post that I was almost finished I am going to breifly explain all of the other challenges towards my post. Mids and highs are directional yes, however while a tweeter is pointed at the windshield, do you know what happens when the sine wave hits the windshield? It bounces off normally projecting between the headrests of the front seats. Example: 2003 Chevrolet Silverado with the bose sound system off the windshield inbetween both headrests. To bring the point home, 1992 Toyota Celica aimed from the two side veiw mirrors directly inbetween the headrests. Now the whole Isobaric/Clamshell mounting. Not very practical. I have used this setup and have been very dissapointed. To do this right you must overpower the sub and Its not worth the time tuning as where you can throw the two subs into a bandpass box and be happy. as for the bandpass box... Where do the ports come out? All on the same side. Ports = Air flow = Bass notes. This is the way it is. Argue if you want, acoustics work one way there are no bending laws. I appreciate the well thought out counter to the post however, It seems as If i have explained all of the above arguements and for the record, I wrote that post up, I did not copy it from anywhere. Do a little research before you attempt to falsify a statement made by another member on the org.
Ben Becraft wrote:Do a little research before you attempt to falsify a statement made by another member on the org.
The main reason I hate coming on here, esp this forum.
Sam
Ban low-performance cars, not high-performance ones.
Ill wait for the Greatest AUDIO GOD to chime in, Patiently waiting for JLAudioCavalier.
lol.
Oh he is viewing ... but unlike some random douche bags he doesn't think he's a god, and only give true advice, not complete garbage, El
On the other hand....you have other fingers.
I just bought a 20 inch widescreen ultrasharp flat pannel..I'm going to have to subscribe to the high quality porn places now......damn
I think the point he is trying to make is that some of these wild and crazy fiberglass designs are for looks and not for sound, which I completely agree with. Also I have yet to witness a Jbody hit the same numbers with comperable equipment as other vehicles, which I also believe is a point he is trying to make with peaks in the distance of the wave to the passengers. Though it seems like lately we have a ton of people trying to write up stuff to get stickied.
^CLICK ME TO SEE HOW I BUILT EVERYTHING^ How To in Interior Forum
Ben Becraft wrote:For the record, I have been a member of the org since I was 17. I am now 19 and am entertained by how you feel as though you are right because you are older. Now to explain my position completely, Your mentioned two walls of facing subwoofers, tell me where the microphone is set... Probably in the middle of the speakers. Sound pressure will be the highest where all of the speakers are meeting. Picture waves meeting at a central point. There is a lot of energy at that point. the subs are all moving towards a central target that being an SPL mic. For the arguement of me being wrong, go find some water and drop a rock into it. watch the ripples. Now drop two rocks in seperate places... Chaos no smooth ripples but confused ripples. the same with sound waves or sine waves. One side in the other is out. Now because I lost my post that I was almost finished I am going to breifly explain all of the other challenges towards my post. Mids and highs are directional yes, however while a tweeter is pointed at the windshield, do you know what happens when the sine wave hits the windshield? It bounces off normally projecting between the headrests of the front seats. Example: 2003 Chevrolet Silverado with the bose sound system off the windshield inbetween both headrests. To bring the point home, 1992 Toyota Celica aimed from the two side veiw mirrors directly inbetween the headrests. Now the whole Isobaric/Clamshell mounting. Not very practical. I have used this setup and have been very dissapointed. To do this right you must overpower the sub and Its not worth the time tuning as where you can throw the two subs into a bandpass box and be happy. as for the bandpass box... Where do the ports come out? All on the same side. Ports = Air flow = Bass notes. This is the way it is. Argue if you want, acoustics work one way there are no bending laws. I appreciate the well thought out counter to the post however, It seems as If i have explained all of the above arguements and for the record, I wrote that post up, I did not copy it from anywhere. Do a little research before you attempt to falsify a statement made by another member on the org.
It's not an older thing - it's an experience thing, and the knowledge that comes from that experience. I agree with everything Nate said - not because I'm 28 and ready for a pension, but because I've been into car audio for 12 years and SPL for 7, and have learned alot of stuff the hard way when it comes to competition. It's great that you're now an installer. Your examples are quite good in theory. You can't be knocked for that, but the real world throws alot of variables in that seriously screw with the theoretical examples that you speak of. No laws of physics are broken - it's just that a car is infinitely more complicated than any of your models. As an installer, experience should have shown you that.
In the end, it's the acoustics of that individual vehicle that dictates how waveforms behave and how they interfere with each other. What makes things worse is that each vehicle is different, even if you're comparing just cavaliers. It could very well be that works best for my Z24 won't work nearly as well in your car. My 01 Z24 is a completely different beast than my best friend's old 97 coupe. Your perfect world examples do not address any of these little nuances.
For the record - the theory behind your statements (although quite arrogant) is not false....actually it's pretty much how my prof described it in the first week of my intro physics course bck when I was an undergrad. However, it does seem that you don't fully understand just how acoustically complex a car interior is.
Although very simplified, I did think your original post was sticky material.
J.J. Lecznar wrote:... bring ur @!#$ over here and i wil blow what u have to hell.... ill put @!#$in 200 dollars on it...
*wipes tears from eyes*
sticky material, most people have no clue on this.
Tommys truck is metered on the dash. about 6 feet away from the start of the V and about 9 from the center of the V.
My whole point was theory is nice. BUUUUUTTTTT you need to try some things to realize how it works. for instance like doubling cone area or doubling power should result in a theoretical 3 decibel increase right? That is the theory. but many many many times it will result in less. theories are alright to start by and im not arguing about acoustics. I just know what ive dealt with what ive seen and what the others i know have seen.
BTW do you have any pics of your install
Quote:
For the record - the theory behind your statements (although quite arrogant) is not false....actually it's pretty much how my prof described it in the first week of my intro physics course bck when I was an undergrad.
I took science of sound (physics). I think alot of the theory is based on acoustic installs in square rooms or in halls not vehicles.
I agree the first post is sort of sticky material but if you don't know how a sine wave works or interference then you shouldn't be allowed to build a system yourself.
the only time you really have to worry about sound-waves is in the trunk.
how about horn's. and bandpass box's???
im also friends with someone that has a > shaped wall and hes doin 152.3 at 20 hz (i belive). there are alot of setups that are louder with sub's facin other way's.
if you can look up a good friend of mine terry brocks on termpro.com, he has one 10 facin up in one box on the passenger side and one 10 on the drivers side facin the rear 1/4. he also got 1st last year and 3ed in 2004 in street a and still does a 154.7 at the dash on the tp.
oh and the people that are on termpro you didn't hear what i said about his box.
I used to run 12 fifteens in a > shaped wedge wall in my astro. We delayed the speakers that were farther back slightly so that the waves would all hit the front at the same time. worked well.
--------------------------------------------------------------
Offical dealer for the following-
SOUNDSTREAM
DB LINK
DB DRIVE
PANASONIC
GARMIN
ROSEN
SCOSCHE
XE DESIGNS
SOUNDGATE
PAC
LITEGLOW
EVERYONE STAND BACK, I'm gonna see if I can pee over your head.
My Myspace Page
James (ROLN19S) (JuicyJ) wrote:EVERYONE STAND BACK, I'm gonna see if I can pee over your head.
it realy is sad that this is what this forum has come to so often lately... i actualy have been told by others that they avoid the JBO audio forum because they cant stand the immaturity, and random garbage in here sometimes and i can clearly understand it!!
On the other hand....you have other fingers.
I just bought a 20 inch widescreen ultrasharp flat pannel..I'm going to have to subscribe to the high quality porn places now......damn
Lets all step back for a minute... The topic of the post was what? "Just Because It Looks Cool....." The post was directed for those who dont know a lot about audio and see the fiberglass enclosures. Yes all vehicles are very different in acoustic nature. However if you have speakers aimed in every direction It will not ever reach the sound potential that it could if they were all aimed in a way that would provide the best acoustics for the particular application this is all I was trying to say. I was not trying to get stickied, I was not trying to start any sort of disagreement. I was simply posting so that some of the less audio inclined would sort of get the idea behind acoustics. I've been a member of the org since I was in high school where the competition was who could spend the least amount of money and get the loudest setup. I do not compete in SPL competition I see no need. Yes there are variants that I know nothing about in SPL for example putting a Lexan wall in front of a speaker wall... It supposedly makes it louder. Another thing that needs to be realized Is that i think i misspoke about being louder. Sound Quality and SPL are two completely different beasts in themselves. normally any setup that hits high dB's without a well balanced mid and high setup will sound like complete crap. The point was not for an arguement. The perfect world examples are the best way to explain these situations its hard to visualize say a lake with random dam like obsticles to stop the ripples therefore they are a vague yet understandable way to explain these situations.
Fact of the matter is:
Fiberglass speaker enclosures with subs facing every which way will never be as loud as the subs facing one way setup
it causes destructive interference end of story that was the point of this post.
