box idea for 2 Re re 12's

[SPL140.2 5,000+ posts]

It's all proven and tested....

By who? Have done the testing for spl use and having one chamber for two subs has more spl than them having their own seperate chamber. //content.invisioncic.com/y282845/emoticons/tongue.gif.6130eb82179565f6db8d26d6001dcd24.gif

 

[swimfreak26 10+ year member]

You ought to read into things a little further. There is a reason for the PREFERABLE option of giving each sub its own chamber. rather then what is COMMON. Because what is common, is a production style cheaply designed and built enclosure.... YOu are right about how common it is... IT is extreamly common. People don't pay attention to details and go for what is easiest. They could have a box that performs well..... until once somthing for some odd reason happens like a sub fails to perform any more and decides to quite. then you have only one sub pushing the air and it would then be out of tune. Not to mention your average person doesnt know the difference between a good sounding box and a GREAT sounding box. They generally go for looks, and price..... always price.... That is where car audio business men make their money because they know this. People will pay alot for mediocrity, as long as it looks good. And it takes the fabricator less time and effort to build the box. THis is why it is so Common...
First, the devider provides reinforcement. the bracing is always a plus.

Second, each driver though it is the same brand and model perform slightly differently. By giving a seperate chamber, you isolate one from the other to prevent resonant friction between the two.

third, if you run your subs in stereo mode rather then mono

fourth, incase one sub fails.... you will only end up with one sub that is damaged rather then two.

the seperate chamber gives additional suport and isolates the subs from eachother

It's all proven and tested.... Yes it is common to have more then one sub per enclosure. you often find them in sealed fiberglass enclosures. They are for looks, and they cost alot of money, and they often sound okay. However they would actually sound alot better, given the subs are built to their own seperate chamber. (you can still do this while giving the same exact shape as the box without the internal deviders. Takes more time, but produces better cleaner sound quality, frequency response, and over all SPL since you have a much more sturdy box with the subs playing in exactly their intended box volume........

And last but not least, if your system is a couple 200 RMS pioneer or Kenwood 12's. then this isnt that big of a deal.... THis guy has a couple really nice subs. he ought to compliment them with a solid *** box.

Arguments will fly out from this one! I can't wiat to hear it.......

lets discuss.

Please quit spreading that filth around here and telling people they have to have separate chambers for each driver while running ported, it is just simply not true.

The physics behind it show that actually you'll get better sound out of a common (shared) chamber, rather than two separate ones because you're using the exact same volume and tuning, rather than taking chances with slight differences in the building of each chamber.

Now...you're also saving space by using a single shared chamber because you only need one port instead of two which saves the volume of the chamber dividing wood as well as one of the ports' walls.

Beyond that, it is true that if one sub goes, the mechanical handling of the other decreases because its effective enclosure volume doubles, but that is generally worth the risk.

Do yourself a test and ask how many people on here have separate chambers in a ported box...then ask all the box builders on here how they run it, you'll find something very similar even with those folks who compete....they run a shared chamber. And don't go babbling about how people don't know the difference in sound because some of the people on here have a TON of experience with different boxes.

 

[InhumanAcura 5,000+ posts]

how can you post a link from your own personal experiences in differences of the two?
but for reinforceing reference, read some books by Joe Pettit, or Mark Rumreich. The best way is to build two enclosures and note the SIGNIFIGANT difference. build them with one chamber for two.... then devide the exact volume in half and build two seperate chambers tune the boxes exactly the same.....

Come on man.... if you think about it.... I mean you don't have to strain your brain to think about this one....... Realize the mechanical theory behind sound reproduction. Note where the losses in SPL or sound quality come from in an enclosure. It only makes sence any way.

well, think about it...do you ever see subs divided in the loudest vehicles/walls/etc...no....

please dont say tested and proven....then say "from personal experience"...because that dont mean shit when theres a bizillion variables...

...ill add that ive tested more boxes/subs than i can begin to count...and i own a sensor....but, you'll NEVER see me post "tested and proven" because if i take my "tested and proven" facts to another vehicle everything goes out the window...

 

[InhumanAcura 5,000+ posts]

joeldirt i believe your ****ed knowledgable on audio...but, you just seem to have a knack for stating things the wrong way..i honestly dont want to sit here and but heads with you //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[joeldirt 10+ year member]

joeldirt i believe your ****ed knowledgable on audio...but, you just seem to have a knack for stating things the wrong way..i honestly dont want to sit here and but heads with you //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

this is probably one of the most true statements in this thread so far. lol I do have a tendancy to word my self incorrectly. First of all, I knew that when I started this little fire it would get heated up wuite quickly and people would be easily irritated and annoyed. My bad for tugging on nerve endings. I was jsut having a bit of fun. However I did go about it wrong by mis stating what I was saying... so to try and clear my self up....

Tested and proven..... What exactly did I mean by that? well lets see here. I very began building subwoofer enclosures when my friends chevy pick up got submerged in water when we were off roading. the box was ruined. so I decided to make him another when it was my fault after all telling him to go in that "puddle" that turned out to be a little pond. any how I took my cabinetry skills and incorportated them into a new sealed enclosure for a couple 12" rockford Fosgates. We expected the same sound, but we got a whole other sound that we ended up likeing ten times better. Granted it was probably because the other box was slapped together with a couple brad nails and some carpet... I don't actually know. But I was pleased with the out come. I began building enclosures for my friends as they started putting your average system in their car. THe boxes got better and better, and I began to get more and more interested in them. So, I started getting a reputation arround my Marine Corps base and began replacing boxes as people wanted more custom enclosures for their cars. And I was cheap since it was fun and easy for me to do since I already had all the necesary tools. SO what I had ended up doing was started comparing the boxes I was replacing with my own. I understood basic concepts and ideas of how to construct boxes, and I actually work with composite materials on **** near a daily basis with my helicoptors. SO I began incorportaing fiberglass aswell. I read books on box construction and how to tune and port boxes and such. I began to develope my own preferences as the better sounding boxes generally came from adding a second chamber to devide one form the other. They sounded much better then the ones I was replacing, and I always had a happy customer as an end result. Maybe SPL was only increased because the boxes they had were cheap premanufactured boxes where as mine were built like a rock. I didnt pay any attention to what the ones I was replacing were tuned to, as I loked up the specs on the subs my self and came up with my own box perameters for them. Maybe the difference in how I built them were what gave them the added SPL, they for sure **** did sound a whole lot better with SQ as well. that was the noticeable difference. When they thought their enclsoures sounded good in the begining, they wanted either a little more custom look, or what ever. the difference in the sound differed so much that it was to them a GREAT sounding box. I have a good ammount of compare and contrast, and I have always found the BEST results with the subs in their own chambers. Sealed boxes are a given, I always will give the subs their own shamber. Ported, I will also build some depending on the style of the box with two per, however I generally prefer to give them their own chamber. It's personal preference, and I always get awsome results. My friends tell me I have knack for this stuff and that I should own my own business when I get out of the USMC. I am a helicoptor mechanic, not a subwoofer enclosure specialist. But I do knwo what I do know about my own experiences, which is a huge hobby of mine. And I have MANY years in fine cabinetry. So my tests, and proof, is not a direct result from my acoustic engeneering degree, or my vast years of experience in car audio. I apologize, as I knwo I am not a know it all. However I do know a great deal since I spent the time to read books, ask questions, and aply my skills hands on. Not to mention, I believe in Sound quality, and that is what I was enphisizing on form the begining. Not SPL, and I did mention SPL, though that was from my own experiences with the replacement of more then likely booty *** boxes.

and: "The physics behind it show that actually you'll get better sound out of a common (shared) chamber, rather than two separate ones because you're using the exact same volume and tuning, rather than taking chances with slight differences in the building of each chamber."

I don't know about you, but I can build two chambers exactly the same.

and: "I dont use the recommended box volume suggested by the manufactures. I use a larger box due to efficiency."

I don't recall ever saying anyhting about strictly adhereing to manufacturer suggested volume. Their volumes are general based upon the average consumer, and the needs and constraints of each individual aplication. The give a small window of what the sub is actually capable of handling in. TO keep it simple for the average person, since every person doesnt want the exact same sound.

any way I think that is enough self explination.

 

[SPL140.2 5,000+ posts]

When I was first interested in SPL I made several boxes 1 large enclosure and 2 almost of the same. I have been talking to the technical advisor for SPL Dynamics for about 1 year and wanted to do the test as he recommended. Within this 1 year period I have tested the 2 of the same. Box 2a-internal box volume was 3.47cub ft sharing a chamber for 2 of the SPL ML line subs. It was ported to 40hz with a slot port. I went outside with a cheap radio shack spl meter and got different scores in db at the same volume but at different test tones. In box 2b- internal box volume was 3.7 cub ft, pretty close to 3.47 in box 2a. This box had two seperate chambers per sub each chamber had a slot port tuned to 40hz also. Did the same as box 2a, put it outside, used the same subs as box 2a. and had used the same volume on the head unit and placed the meter the same length away from the enclosure (8 ft.) and went through the same test tones as box 2a. I tested this outside because of differences in cars, suv's.... Since im mostly interested in spl competition and the technical help from Karl, I wanted to see which enclosure would present a higher number in DB's. In my personal tests of those 2 enclosures the box 2a. presented a significant higher number in DB's at each tone tested than box 2b. So as you can see in my personal test 2 12"s sharing the same chamber had more spl. Im NOT DISSEN you in anyway, just wanted to share my test with you, try it sometime and youll see what Im talking about. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[tj'sProbe 10+ year member]

so wheres my dimensions??? //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[InhumanAcura 5,000+ posts]

this is probably one of the most true statements in this thread so far. lol I do have a tendancy to word my self incorrectly. First of all, I knew that when I started this little fire it would get heated up wuite quickly and people would be easily irritated and annoyed. My bad for tugging on nerve endings. I was jsut having a bit of fun. However I did go about it wrong by mis stating what I was saying... so to try and clear my self up....
Tested and proven..... What exactly did I mean by that? well lets see here. I very began building subwoofer enclosures when my friends chevy pick up got submerged in water when we were off roading. the box was ruined. so I decided to make him another when it was my fault after all telling him to go in that "puddle" that turned out to be a little pond. any how I took my cabinetry skills and incorportated them into a new sealed enclosure for a couple 12" rockford Fosgates. We expected the same sound, but we got a whole other sound that we ended up likeing ten times better. Granted it was probably because the other box was slapped together with a couple brad nails and some carpet... I don't actually know. But I was pleased with the out come. I began building enclosures for my friends as they started putting your average system in their car. THe boxes got better and better, and I began to get more and more interested in them. So, I started getting a reputation arround my Marine Corps base and began replacing boxes as people wanted more custom enclosures for their cars. And I was cheap since it was fun and easy for me to do since I already had all the necesary tools. SO what I had ended up doing was started comparing the boxes I was replacing with my own. I understood basic concepts and ideas of how to construct boxes, and I actually work with composite materials on **** near a daily basis with my helicoptors. SO I began incorportaing fiberglass aswell. I read books on box construction and how to tune and port boxes and such. I began to develope my own preferences as the better sounding boxes generally came from adding a second chamber to devide one form the other. They sounded much better then the ones I was replacing, and I always had a happy customer as an end result. Maybe SPL was only increased because the boxes they had were cheap premanufactured boxes where as mine were built like a rock. I didnt pay any attention to what the ones I was replacing were tuned to, as I loked up the specs on the subs my self and came up with my own box perameters for them. Maybe the difference in how I built them were what gave them the added SPL, they for sure **** did sound a whole lot better with SQ as well. that was the noticeable difference. When they thought their enclsoures sounded good in the begining, they wanted either a little more custom look, or what ever. the difference in the sound differed so much that it was to them a GREAT sounding box. I have a good ammount of compare and contrast, and I have always found the BEST results with the subs in their own chambers. Sealed boxes are a given, I always will give the subs their own shamber. Ported, I will also build some depending on the style of the box with two per, however I generally prefer to give them their own chamber. It's personal preference, and I always get awsome results. My friends tell me I have knack for this stuff and that I should own my own business when I get out of the USMC. I am a helicoptor mechanic, not a subwoofer enclosure specialist. But I do knwo what I do know about my own experiences, which is a huge hobby of mine. And I have MANY years in fine cabinetry. So my tests, and proof, is not a direct result from my acoustic engeneering degree, or my vast years of experience in car audio. I apologize, as I knwo I am not a know it all. However I do know a great deal since I spent the time to read books, ask questions, and aply my skills hands on. Not to mention, I believe in Sound quality, and that is what I was enphisizing on form the begining. Not SPL, and I did mention SPL, though that was from my own experiences with the replacement of more then likely booty *** boxes.

and: "The physics behind it show that actually you'll get better sound out of a common (shared) chamber, rather than two separate ones because you're using the exact same volume and tuning, rather than taking chances with slight differences in the building of each chamber."

I don't know about you, but I can build two chambers exactly the same.

and: "I dont use the recommended box volume suggested by the manufactures. I use a larger box due to efficiency."

I don't recall ever saying anyhting about strictly adhereing to manufacturer suggested volume. Their volumes are general based upon the average consumer, and the needs and constraints of each individual aplication. The give a small window of what the sub is actually capable of handling in. TO keep it simple for the average person, since every person doesnt want the exact same sound.

any way I think that is enough self explination.

cliff notes?, i gave up after the first paragraph...

 

[joeldirt 10+ year member]

so wheres my dimensions??? //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

sorry I got distracted between work and this fun little dispute. I'll give you dimensions for both two chamber box, and one chamber box and let you decide which one you wnat for your self. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[tj'sProbe 10+ year member]

well to be truthful wouldnt it be better to do a two chamber box though. It isnt like it is going to hurt it the most it could do is help me. Just give me the numbers and we will go from there lol.

 

[tj'sProbe 10+ year member]

dimensions?

 

[tj'sProbe 10+ year member]

? anyone ?