Enclosure for deep bass.

[SubsonicSounds 10+ year member]

Why don't you just cut into your reak deck ( Like an IB setup )... And seal off the trunk. ... Kind of like how Lexus does their rear stage ( 10" sub in rear deck only ).

Actually, that would be a good possibility with potentially superior results. This way of baffling the sub would provide an enourmous amount of effective box volume behind the cone. I would without a doubt be losing a significant amount of power handling, as the air reflex effect would be very low, allowing for more unrestricted cone movement, eventually reaching the limits of excursion. I will have to see how my sub performs in the box that I designed (should have it by Friday), to see how much of a factor the electromechanical limits of the suwoofer design will be.

The rear stage infinite baffle design has two inherent advantages that immediately come to mind.

1. The sound waves are reflecting directy from the rear window towards the front of the car, possibly producing low frequencies with better sound imaging for the front seat listener.

2. The air pressure restrictions behind the cone will be very limited, which could be advantageous for low frequency propogation in the way mentioned above.

Ever heard a well amplified pair of 6x9's mounted in the stock location? Some can hit pretty low!

Disadvantage:

However, in my current plans, with the sub front face playing into the trunk, with one seat down, I am effectively using the trunk as a source of interior gain.

Nonetheless....

Good call Nissan. Btw, since you seem to know about some specific applications of IB subs in factory installations, don't be afraid to post links! Don't think for a minute that I wont read them.

 

[SubsonicSounds 10+ year member]

How about, you make a sealed AND ported box..
Now thats an idea..

Do you mean utilizing sealed and ported technology at the same time in some type of bandpass, or do you mean actually making two seperate boxes? I have metioned experimenting with both types of enclosure and probably will.

 

[miker 5,000+ posts]

Do you mean utilizing sealed and ported technology at the same time in some type of bandpass, or do you mean actually making two seperate boxes? I have metioned experimenting with both types of enclosure and probably will.

I mean experimenting with both kinds,

Sorry I just read the first page and part of the last, and that was all I could think, since it's not even a large enclosure trying a couple boxes won't take too much time or cost too much.

 

[SubsonicSounds 10+ year member]

I agree, and as I said, I still can utilize both boxes regardless of the outcome.

 

[helotaxi 5,000+ posts]

***New Question*** In a rectangular enclosure, is there a problem mounting the driver closer to one end of the enclosure, or does it need to be centered to eliminate uneven pressure on the back of the speaker? In other words, will I cause unwanted damage or distortion by having the speaker close to one end of the enclosure?

At sub bass frequencies, there are no "inbox reflections" or anything of that sort to worry about. There are no "waves" inside the box at all. The frequencies in question have a 20+ ft wavelength. The air inside the box simply pressurizes as a whole and rarifies as a whole as the cone moves. You're thinking WAY to much about this and assuming that concerns exist where ther are none.

You could build an extremely low tuned ported enclsure and accomplish whatyou want but it will have 2 characteristics that will be detrimental to your goal. First it will have to be HUGE. Second the port will have to be HUGE making the gross size of the box that much bigger. To be playing the freqs that you're looking for, you're looking at a tuning of 20hz, probably lower. Power handling will not be any better than with a large sealed box because the enclosure would have to be very large to keep the output around tuning from being suppressed below what you would get from a large sealed enclosure at that frequency. Yes, that's what happens when you put a sub in a ported enclosure tuned much lower than it wants to be tuned, output actually drops (which kinda defeats the purpose to going ported in the first place). You have to make the box HUGE to boost that low output shelf back to somewhat normal levels. You can't get around Hoffman's Iron Law, even with a ported enclosure. You can have efficiency, low frequency extension and a small box, pick two.

 

[SubsonicSounds 10+ year member]

I have decided to go a different direction with this enclosure design. I am not going to disclose any information yet other than saying that I am confident that my original expectations will be exceeded. I will also say that I have discussed my plans with the right people.

I will do my best to document performance when the enclosure is complete. Thanks to all that offered input. You have prompted me to investigate more deeply into this endeavor, which has opened up a few doors that I did not know existed.

 

[BEAVER.989 10+ year member]

I have decided to go a different direction with this enclosure design. I am not going to disclose any information yet other than saying that I am confident that my original expectations will be exceeded. I will also say that I have discussed my plans with the right people.
I will do my best to document performance when the enclosure is complete. Thanks to all that offered input. You have prompted me to investigate more deeply into this endeavor, which has opened up a few doors that I did not know existed.

Oh no, he's going to a PR set-up. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[PV Audio 5,000+ posts]

Well... First off... 25hz w/ a 10" Type ARRHHHH ????? That's goin' to be a VERY faint note.2nd: you're not goin' to achieve more excursion in a sealed box.

* Being sealed = tighter bass, stiffer sub... It doesn't give your sub any time to move. ( Like you're wanting it to )

3rd: you need a ported enclosure...

You really don't know what you're talking about, do you?

 

[PV Audio 5,000+ posts]

Subsonic, what do you do for a living? You seem to have a solid knowledge of wave and acoustic vibrations theory, but they don't apply here. As an engineering student, I'll let you know that what you learn in the classroom doesn't really apply to car audio half as much as it does for home audio. This is why you design enclosures entirely different depending on the architecture surrounding the system. If you're not set, listen to helotaxi; he's smart as **** with this **** and I learned a lot from him before he vanished a few years ago //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 

[NissanKicker 10+ year member]

I don't know what I'm takin' about????

... That's funny.

 

[SubsonicSounds 10+ year member]

Oh no, he's going to a PR set-up. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

Not sure what you are referring to. What do you mean by "PR"?

 

[SubsonicSounds 10+ year member]

Subsonic, what do you do for a living? You seem to have a solid knowledge of wave and acoustic vibrations theory, but they don't apply here. As an engineering student, I'll let you know that what you learn in the classroom doesn't really apply to car audio half as much as it does for home audio. This is why you design enclosures entirely different depending on the architecture surrounding the system. If you're not set, listen to helotaxi; he's smart as **** with this **** and I learned a lot from him before he vanished a few years ago //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

I absolutely agree with your comments on automotive interior architecture, there are endless variables that affect the propogation and transmission of wave energy throughout the vehicle, further compounded by even the very dynamic nature of the vehicles many possible geometrical configurations. This "listening room" (to compare what is being done to a home audio setup) that we are trying to create changes inherently everytime a window is adjusted, a sunroof is opened, a seat position is changed, and profoundly as the barometric pressure fluctuates.

I also agree that while extensive knowledge of physics allows an enthusiast to better understand the results of actual experimentation within our "labs" (vehicles), one cannot possibly fully predict the behavior of drivers, and the waves that they produce in any vehicle. Prior knowledge of science helps us plan, but new, further understanding of science (through the learning that takes place prompted by data gathered from experimentation) is what allows us to move forward and make improvements.

One more quick comment. (PV this part is not directed at you) Although I am new here, I would like present one idea. Instead of offering a purely negative feedback, or feedback that is overly simplified and in absence of sufficient explanation, try offering a comment that is well grounded in some type of research, or honest and accurate prior knowledge that has been tested sufficiently, rather than a resonse driven by sarcasm or satire or the likes of. I would speculate that the amount of learning that takes place in this forum would increase. I just want to understand the most possible, and hopefully help others do so as well in the future. For reference, this thread has not been a problem, and has been very helpful as stated above.

Just my personal insight. Take it as you wish, for whatever its worth.

Thanks again for all of the input.

 

[TurdFergueson2 5,000+ posts]

I absolutely agree with your comments on automotive interior architecture, there are endless variables that affect the propogation and transmission of wave energy throughout the vehicle, further compounded by even the very dynamic nature of the vehicles many possible geometrical configurations. This "listening room" (to compare what is being done to a home audio setup) that we are trying to create changes inherently everytime a window is adjusted, a sunroof is opened, a seat position is changed, and profoundly as the barometric pressure fluctuates.
I also agree that while extensive knowledge of physics allows an enthusiast to better understand the results of actual experimentation within our "labs" (vehicles), one cannot possibly fully predict the behavior of drivers, and the waves that they produce in any vehicle. Prior knowledge of science helps us plan, but new, further understanding of science (through the learning that takes place prompted by data gathered from experimentation) is what allows us to move forward and make improvements.

One more comment. Although I am new here, I would like present one idea. Instead of offering a purely negative feedback to comments that have been made in a thread, try offering a comment that is well grounded in some type of research, or honest and accurate prior knowledge that has been tested sufficiently, rather than a resonse driven by sarcasm or satire or the likes of. I would speculate that the amount of learning that takes place in this forum would increase. I just want to understand the most possible, and hopefully help others do so as well in the future.

Thanks again for all of the input.

Words..........lol

 

[PV Audio 5,000+ posts]

I don't know what I'm takin' about????... That's funny.

I'm glad you have a sense of humor, because I personally don't find someone wanting deep bass being told to tune to 40hz and then spouting acoustical fallacies to be humorous.

 

[PV Audio 5,000+ posts]

Oh, you're that trunk wars guy. Got it now.

 

[PV Audio 5,000+ posts]

I absolutely agree with your comments on automotive interior architecture, there are endless variables that affect the propogation and transmission of wave energy throughout the vehicle, further compounded by even the very dynamic nature of the vehicles many possible geometrical configurations. This "listening room" (to compare what is being done to a home audio setup) that we are trying to create changes inherently everytime a window is adjusted, a sunroof is opened, a seat position is changed, and profoundly as the barometric pressure fluctuates.
I also agree that while extensive knowledge of physics allows an enthusiast to better understand the results of actual experimentation within our "labs" (vehicles), one cannot possibly fully predict the behavior of drivers, and the waves that they produce in any vehicle. Prior knowledge of science helps us plan, but new, further understanding of science (through the learning that takes place prompted by data gathered from experimentation) is what allows us to move forward and make improvements.

One more quick comment. (PV this part is not directed at you) Although I am new here, I would like present one idea. Instead of offering a purely negative feedback, or feedback that is overly simplified and in absence of sufficient explanation, try offering a comment that is well grounded in some type of research, or honest and accurate prior knowledge that has been tested sufficiently, rather than a resonse driven by sarcasm or satire or the likes of. I would speculate that the amount of learning that takes place in this forum would increase. I just want to understand the most possible, and hopefully help others do so as well in the future. For reference, this thread has not been a problem, and has been very helpful as stated above.

Just my personal insight. Take it as you wish, for whatever its worth.

Thanks again for all of the input.

Just to let you know, your writing style is far above the average CA.com er's reading level //content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif

 

[SubsonicSounds 10+ year member]

Just to let you know, your writing style is far above the average CA.com er's reading level //content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif

I write in a highly technical fashion in order to avoid any ambiguity in reader perception of my statements. I think it is approiate for the desired level of technicality in the discourse of this particular thread.

While I do understand that writing may seem shifted towards the advanced end of the spectrum, I certainly do not think that the experience (of reading through this thread)is going to be detrimental to anyone in the long term.

To put it in simpler words... it's good to get some higher level reading practice.

Also, I will be the first to admit that my spelling is mediocre.

 

[SSS 18734 5,000+ posts]

SubSonicSounds,

I'm shocked whenever I see someone on this site that has even a basic knowledge of the English language. The fact that you can structure sentences is fantastic, and as such, I would assume that you're looking for some knowledgeable people to share your ideas with.

Therefore, I would HIGHLY recommend you visit the forum at http://www.soundsolutionsaudio.com and post your discussion there.

More often then not, this forum is a complete joke. (Which is why I love it so much) //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 

[helotaxi 5,000+ posts]

Yep, it really is nice and somewhat shocking to find complete sentences on this forum. SSA has a higher audio IQ on average than this place. The trolls and idiots here chased a lot of the smart guys over there and few of them make very regular appearances here any more, though some of them are, in fact, mods on this forum.

 

[PV Audio 5,000+ posts]

If anything, ask this on diyaudio.com or avsforum.com. Both sites would gladly help you if you conduct yourself in a professional fashion, but be warned, their collective sense of humor is nonexistent.