Enclosure for deep bass.

[Krown 10+ year member]

Don't forget that using enough polyfil will basically "enlarge" the enclosure.

 

[NissanKicker 10+ year member]

Helotaxi:

... for one... I do know what he's talkin' about and tryin' to accomplish.

Quote:

" I don't see any reason to attempt it with a single not-so-great 10" sub...thats like trying to use a bicycle to break the world record for land speed. You might as well start with an advantage at least. "

BINGO! - the note to going to be faint. only thing that was mentioned was, I wanna hit the LOWS!.... earthquaking effect bass... go ported... Easiest way.

NOW!

... As far as a sealed hitting lows, that's no doubt. sealed has a fuller range on music OVER port-tuned enclosures. I had 4 cvx 12s and you felt 15hz like a 30hz note. I'm not denyin' nor taken anything away from a sealed enclosure nor his ideas. I'm just simply stating " if you feel it can be done, do it. I showed him the enclosure needed... If not, I'll tune it to 20hz ( for a 10... I don't know why but ok ).

As for as a T-line box, there's no need and I don't have to speak on that ( that's been taking care of - Helotaxi )... ALL & ALL, there's a simpler way to do it. But as you stated - Just for knowledge and a better understanding.

GoodLuck Bro.

 

[SubsonicSounds 10+ year member]

You are only partially getting how a ported enclosure works. There is no reason to consider a T-line or any 1/4 wave design. The resistance of the port and the effect of that resistance from a given area and length relative to a given enclosure volume is very predictable and well modeled by the standard enclosure calculations. But I still agree with you that a sealed enclosure is the way to go for the really low stuff.

You are absolutely correct. I think i am only partially understanding how a ported enclosure works (i do mean in relative terms). That is one of the reasons why at this point I am opting to avoid the ported enclosure. I'm somewhat concerned with the effects on the waves during the compression and subsequent decompression processes through the restrictive points encountered while exiting the enclosure. I know that there is research out there, and I know that many on this forum can help me understand, but that is for another day. I'm hoping to go that direction after I have a sealed setup completely figured out.

Really like the choice of music. I listen to everything (almost) as well and I really like Techmaster P.E.B. and have for years.

P.E.B. was a talented composer, with unmatched mixing abilities for his time. Some of his work was capable of putting me in a dreamlike state LOL.

Nissan, I do believe that you understand what I am interested in accomplishing, and I thank you for wishing me luck. I think it will be needed in finding someone to construct my enclosure around here where I live. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[helotaxi 5,000+ posts]

Helotaxi:... for one... I do know what he's talkin' about and tryin' to accomplish.

If you're recommending a ported box tuned to the high 30's, ummm, no, you obviously don't. Even Alpine recommends a lower tuning, and my experience has shown the manufacturer spec enclosures are usually a little small and tuned a little high. Better SPL, which is what most people want. Tuning higher than that is only going to make the response peak bigger and steepen the rolloff below that. The effect would be to cut the lows even more, which is definitely not what he was looking for.

There's no reason that sub shouldn't be able to go well below the audible spectrum in-car in a sealed box. It isn't going to really take your breathe away because it's still just a 10, but it'll still ba able to get down there. Cabin gain will help it out a lot in that regard. Pretty much any sub will be able to go below the audible range sealed in a car.

 

[BEAVER.989 10+ year member]

I also recommend a low tuned ported enclosure. The problem with building a larger sealed box with q approaching .5 is that you'll quickly run out of excursion while trying to reproduce the lowest octaves.

With a ported enclosure excursion is significantly reduced near the tuning frequency which allows you to apply more power. This, along with the increased efficiency of the ported design is going to best accomplish what you're after, IMO.

 

[SubsonicSounds 10+ year member]

... Even Alpine recommends a lower tuning, and my experience has shown the manufacturer spec enclosures are usually a little small and tuned a little high. Better SPL, which is what most people want. Tuning higher than that is only going to make the response peak bigger and steepen the rolloff below that. The effect would be to cut the lows even more, which is definitely not what he was looking for.
There's no reason that sub shouldn't be able to go well below the audible spectrum in-car in a sealed box. It isn't going to really take your breathe away because it's still just a 10, but it'll still ba able to get down there. Cabin gain will help it out a lot in that regard. Pretty much any sub will be able to go below the audible range sealed in a car.

You have seemingly pinpointed exactly what i am trying to accomplish and why I would attempt it. I thank you for taking the time to evaluate what I am attempting, and acknowledging it pheasability. I agree with your theory on manufacturer recommendations. The are most likely trying to "impress" the customer, rather than prompting the flattest possible frequency response without rolloff.

 

[SubsonicSounds 10+ year member]

***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?

 

[BEAVER.989 10+ year member]

I recommend that you download WinISD (it's free) and model the sub in a variety of enclosures to see for yourself exactly what you can expect to get out of a given enclosure.

 

[BEAVER.989 10+ year member]

***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?

Stuff the sub all the way to one side. How else are you going to have enough room for that port? //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

Seriously, it won't hurt anything to do it that way... even if it's sealed.

 

[SubsonicSounds 10+ year member]

I'm not doing the ported. Im actually doing the sealed, and my current drawing has it all the way to one side for better in vehicle location. However, it seems that on the rear of the cone (the part exposed to the inside of the box), the side that is close to the side of the box will not recieve as much reflected wave energy as the side that is more open to the bulk of the enclosure.

Im afraid this may cause lateral movement of the cone, which would cause voice coil deflection, and therefore causing a decrease in motor efficiency, and possibly some rubbing issues between the voice coil and magnet. It would be like putting your hand on one side of your cone and pushing it back. The uneven push causes lateral movement that causes an audible scratching sound between your v.c. and magnet. This is damaging the coil, and if the speaker were playing, temporarily destroying the overall geometry of the motor structure.

I have already ordered the box, so i guess im just hoping that I am wrong.

Maybe the air inside the box will do its job of equalizing in air pressure causing a balanced push from all directions. Yes/No?

Maybe the pressure will be low enough not to significantly effect cone movement.

Maybe I think too much. Anyone in the know?

 

[Buck 5,000+ posts]

ported. end of discussion

 

[BEAVER.989 10+ year member]

I'm not doing the ported. Im actually doing the sealed, and my current drawing has it all the way to one side for better in vehicle location. However, it seems that on the rear of the cone (the part exposed to the inside of the box), the side that is close to the side of the box will not recieve as much reflected wave energy as the side that is more open to the bulk of the enclosure.

If that were a valid concern home audio speakers would place the woofer in the center of the cabinet instead of the very bottom...

I think you're overthinking things, man... nothing wrong with that, though. I am much the same.

 

[SubsonicSounds 10+ year member]

If that were a valid concern home audio speakers would place the woofer in the center of the cabinet instead of the very bottom...
I think you're overthinking things, man... nothing wrong with that, though. I am much the same.

Thought the EXACT same thing, but once again began thinking about it, and I believe that most of the "tower" type home enclosures that you are speaking of are chambered, which would creat a small enclosure at the bottom where the speaker would actually be centered.

 

[BEAVER.989 10+ year member]

some are chambered, some are not. you have nothing to worry about.

 

[SubsonicSounds 10+ year member]

ported. end of discussion

Oh, man. Thanks. I think im just going to go back to bed and sleep knowing that my problems are all so simply solved. And to think guys, all this could have ended with 4 words. LOL.

If you read above, someone suggested that. But I think most would agree that it was certainly not the end of the discussion.

To be fair...

I do know that a vented enclosure will be the optimum type for this ASSUMING a relatively ideal enclosure design, but I think we have established that creating a relatively ideal vented design for my tastes would be very time consuming, and would take up a great deal of space to house the required length tubes for my tuning frequencies without creating wave distortion through the compression/decompression process.

 

[BEAVER.989 10+ year member]

I'm not going to try to twist your arm, but I really believe the ported solution is best, as well.

If it's just the matter of designing the enclosure that's holding you back, speak up. I'll be more than happy to model up a design for you in WinISD, if you'd like.

Ultimately, it's your decision, though. If you're more comfortable with a sealed design, then stick with it. I wish you luck in whatever you decide to do.

 

[SubsonicSounds 10+ year member]

some are chambered, some are not. you have nothing to worry about.

I can speculate that the air pressure effects that I am worried about could be negligible considering the overall internal volume of the enclosure. I can see how the situation that i am worried about would be no different than the effects of speaker location relative to panels of the cars interior in some cases with trunk mounted subwoofers.

You might be right. Thank you for the insight.//content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[SubsonicSounds 10+ year member]

I'm not going to try to twist your arm, but I really believe the ported solution is best, as well.
If it's just the matter of designing the enclosure that's holding you back, speak up. I'll be more than happy to model up a design for you in WinISD, if you'd like.

Ultimately, it's your decision, though. If you're more comfortable with a sealed design, then stick with it. I wish you luck in whatever you decide to do.

I may actually ask you for some help in the near future. I do need to finish this project first. The good news is if I eventaully design a vented enclosure (leaning towards T-Line), I have a 10 inch type-e as well that can be used in whatever box I do not decide to keep. Just throw that in the closed and connect it to a home amp.

 

[NissanKicker 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 ).

 

[miker 5,000+ posts]

How about, you make a sealed AND ported box..

Now thats an idea..