Enclosure for deep bass.

[SubsonicSounds 10+ year member]

First post, so hello to all.

I am thinking about getting a new sealed enclosure for a single 10 inch Alpine Type R. My goals for this enclosure are based on my personal tastes in the total sound experience, which are probably different from many.

I listen to many types of music, but the most important genre to me for the purpose of this project is bass music. I have been listening to bass on a variety of different setups since the days of techmaster p.e.b.

Before describing what i am trying to accomplish, let me start by explaining that I understand I am not using what many would consider the optimal driver for obtaining very low frequencies such as those below 20Hz. I understand the limitations of cone area and the direct relationship between that and movement of air. However, I am still attempting to meet my goal so...

What I am trying to accomplish from this enclosure:

1. Having something unique that suits my personal interests.

2. Using the 10 inch Type R driver in a sealed enclosure.

3. Tuning in the lowest of frequencies as much as possible. I love the lowest note on Bass I Love You, and actually can hear it decently well with my current box, with the left-side back seat in the down position. I do want more if possible.

4. Audio system is commonly used with engine off, windows cracked for best frequency response. I do not necessarily listen to this system very loud, although I am still getting alot of rattling inside the cabin.

Here is what I came up with.

1. Large box to allow the most unrestricted cone excursion, therefore propogating the cleanest possible low frequency sound waves for this sub..

External Dimensions:

H - 13.0 in

W - 15.0 in

L - 24.0 in

Assuming 3/4 inch MDF, that would give me approx 2.8 cubic feet if i calculated right.

Please post a response telling me what you think, and if there is anything I should know about accomplishing this goal of trying to go as low as possible. Am I on the right track or am I somewhere out in left field wandering aimlessly.

Thanks in advance.

Click to read more...

 

[NissanKicker 10+ year member]

Just to put you up on game...

... There is NO tuning for a sealed enclosure.

Only thing you can do with a sealed enclosure for that sub is make it around 1.5cuft and include about 50% polyfill.

... or go with a ported enclosure tuned @ 40hz ( 38hz at the lowest )

 

[SubsonicSounds 10+ year member]

Thank you for taking the time to respond, and perhaps you are correct.

But... once again everything i understand about physics and the laws of motion suggest that the volume of air behind a subwoofer would change quite a few parameters that would directly effect the overall performance characteristics of the driver.

My main concern would be air pressure behind the subwoofer. When the speaker is moving quickly at higher frequencies, higher pressure behind would seemingly assist the cone in returning to its point of origin, which is good when trying to oscilate a reasonably massive object very rapidly.

I however, am going to need some extra excursion, (remember, I am going for 25hz and below) causing a need for the cone to move more freely without overloading the the electromagnetic system.

I am hoping for some more responses to help verify what i am trying to do.

 

[SubsonicSounds 10+ year member]

I do agree on the polyfill, as I believe reflected sound waves will cause the unwanted cone movement, so that is a definite go!

 

[NissanKicker 10+ year member]

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...

 

[tez4life Premium Member]

My personally suggestion is to consider another sub. The Type R 10" doesnt sound like its going to cut it for your desire for subsonics. Are you dead set on that sub?

 

[GLN305 10+ year member]

You want to be careful about putting that 10" in such a large enclosure. The air inside the box acts as a restoring force (hence the term acoustic suspension) and if you have too much air to compress then you lose that restoring force. My recommendation for you is to download WinISD, learn to use it and play with enclosure designs. You are probably going to be pointed in the direction of a low tuned ported enclosure. This will emphasize the very lows ( I like them too). Good luck!

 

[NissanKicker 10+ year member]

This is what you need

... 2.08cuft Overall - tuned @ 38hz.

20"W x 15"D x 12"H

 

[SubsonicSounds 10+ year member]

Nissan, I have just done some quick research. I believe I am correct with my theory on internal volume affecting cone backpressure during excursion, and subsequently the overall frequency response curve of the subwoofer. (If we consider the JL Audio website scientifically sound.) While I will agree with you that there is "less" tuning involved with a sealed enclosure, there is still "some" tuning that can be done, and can be compounded by greater differences in air volume behind the cone. See: infinite baffle.

Also, I would absolutely love to do a ported enclosure guys, but once again, I am really trying to reproduce these low frequencies. Im dealing with very long wavelengths, and to be honest, it would be difficult to create an enclosure that would house vents equaling the quarter lengths of these waves.

To be honest, I would love to try a transmission line box, but I lack the woodworking skill/tooling to do so, and I really do not know where to go or who to approach on that one.

And yes, I did mention above that what I trying to do with what I have is challenging/counterintuitive, but maybe what I learn from this can later to be applied to "bigger" and "badder" subwoofers. I guess you could say I am starting out on a small scale.

That said - low frequency pwns.

 

[NissanKicker 10+ year member]

Like I said you my previous post... That what you need.

... If you see different ( which I'm getting that you do ), I don't know.. But Good Luck!

 

[SubsonicSounds 10+ year member]

This is what you need... 2.08cuft Overall - tuned @ 38hz.

20"W x 15"D x 12"H

38 Hz? AAAAAAAAAgggggggggghhhhhhhhhh! I need LOW!

Ok. Let me see how I can let you know how I like the bass...

Ever throw in a Bass Mekanik CD? You know the really low notes. Many setups won't even hit it. Maybe they have subsonic filters. Maybe ports are tuned high and allow low frequency cancellation.

My setup is can not be like that. I like the bass that seems to undulate. The type of bass that shakes your eardrums back and forth more slowly. The ones that feel like an earthquake has just originated from your trunk... I want the lowest notes! I do care about spl, but not at standard competition frequencies. I care about it at 20hz and thereabouts.

 

[NissanKicker 10+ year member]

a single Type R 10" sub isn't goin' to give you what you want. Sorry. Look @ a DD9910z ...

 

[SubsonicSounds 10+ year member]

a single Type R 10" sub isn't goin' to give you what you want. Sorry. Look @ a DD9910z ...

LOL, I'm not going there.

Once agian, thanks for your input, but don't forget this is purely an experiment. Please don't think that I have the pretense that I am going to attempt to shake windows in drive thrus. I am being realistic in my test setup. I have had louder setups that were probably much more impressive to others. Weren't we all "cool" in high school?//content.invisioncic.com/y282845/emoticons/cool.gif.3bcaf8f141236c00f8044d07150e34f7.gif

This is different.

I don't think I care about the cool factor in any way anymore. I want to better understand how what we are all doing here works. And to begin with, I am trying to learn how to reproduce sound waves in a purely scientific manner under "relatively" real life conditions with intentional limits.

Would it be easier with larger and more subwoofers? Well obviously. Will that help me understand how to better reproduce low frequencies with the current technology at my fingertips? I doubt it.

Could my findings help apply what I have learned on a larger scale in the future? Maybe.

Will I have fun finding out? Absolutely. So please understand that your efforts in trying to discourage me from using the Type "Arrghhh" as you call it, will be entirely futile.

 

[SubsonicSounds 10+ year member]

You want to be careful about putting that 10" in such a large enclosure. The air inside the box acts as a restoring force (hence the term acoustic suspension) and if you have too much air to compress then you lose that restoring force. My recommendation for you is to download WinISD, learn to use it and play with enclosure designs. You are probably going to be pointed in the direction of a low tuned ported enclosure. This will emphasize the very lows ( I like them too). Good luck!

Thanks for you honest concern guys.//content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif And yes Tez, I am seemingly dead set on using this sub. (See reason in my last post). I realize that there are some limits, and the bar is not set very high. However, it is not permanent, as I will undoubtedly suffer from the "its never enough" syndrome and apply what I have learned to bigger and better things.

GLN - I certainly will try the software that you suggested. I have actually worked with some lesser versions of enclosure software, and have learned a few things already. Very valuable stuff.

 

[NissanKicker 10+ year member]

I'm not telling you not to use the type r... I'm just simply stating.. go ported.

... I calculated...

(1) 10" Alpine Type R in a 20cuft. enclosure SEALED ( WOW! )... would be 30.88hz capable.

... Have fun with that.

* 666 post ... That's not a good number *

 

[Witty690 10+ year member]

Everything you want, you will get with a low tuned ported enclosure.

Sealed wont cut it, but i wish you luck anyway.

 

[SubsonicSounds 10+ year member]

I'm not telling you not to use the type r... I'm just simply stating.. go ported.
... I calculated...

(1) 10" Alpine Type R in a 20cuft. enclosure SEALED ( WOW! )... would be 30.88hz capable.

... Have fun with that.

* 666 post ... That's not a good number *

I think you are trying to get me a resonant frequency. Resonant frequency is more important in a vented enclosure, as the port lenght causes an inherent steep roll off below that frequency. Out of phase sound wave cancellation is a killer.//content.invisioncic.com/y282845/emoticons/tongue.gif.6130eb82179565f6db8d26d6001dcd24.gif

Don't let that above number mislead you. I promise that in my current sealed 1.06 cubic ft. enclosure, I can produce enough sound pressure at 18Hz to make it clearly noticeable. I have had 20Hz prompt people to say, "what the heck?" But outside of getting a meter right now at 3am, I cannot make you see that these frequencies are possible from this sub. Granted they are not loud, it is enough to make trunk panels move.

You may still be thinking that this is minimal sound, and compared to your system, im sure it is. But getting the bass to extend low is interesting to say the least.

 

[SubsonicSounds 10+ year member]

Everything you want, you will get with a low tuned ported enclosure.
Sealed wont cut it, but i wish you luck anyway.

I agree with you on the first part. However, in creating a very low tuned vented enclosure, you need to create a vent that is long enough to support the incredibly long wavelengths (that I am for some strange reason going for), by keeping "out of phase waves" from the rear of the speaker from negatively interacting with the "in phase" waves coming from the front.

From my understanding, this is only done by allowing enough time to pass for the "in phase" wave eminating from the front of the speaker to oscilate and become better aligned with the wave coming from the port.

The only way to do this that I can presently concieve of is to create a vent long enough for these long wavefronts to better align themselves, i.e. T-line.

I can see how certain types of more conventional ports could increase internal air pressure by restricting the flow of molecules, thus creating a higher velocity, and shortening the time elapse requirements of the rear-of-cone wave front. But I believe that this would add a variable that might be incredibly difficult to analyze by increasing back pressure on the cone. Anyone well versed in fluid dynamics?

 

[Rashaddd 5,000+ posts]

OP, go with a sealed box.

1. its clearly what you want, so just do it, its easier to mess with anyway than a ported one. You can even build a big one and fill it with solid objects to adjust box size and figure out what kind of differences in freq response you get depending on box size

2. I'm pretty sure I know what you're talkin about with the low "earthquake" type feeling you get from 15hz-25hz, and it seriously can be sick

3. Yes he can get a ported enclosure, but its not going to do what he's looking for very efficiently unless he tunes it to ~20hz

4. I was able to get some serious lows (20-30hz) with a couple sony xplods in just 1.15 cubes each sealed...I'm sure you can do it with some nicer subs, but seriously...just buy an mj 18 or a cheap 15 or somethin. 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.

(video of some of the lows ur talkin about with my old xplods, now sold and gone)

 

[helotaxi 5,000+ posts]

I agree with you on the first part. However, in creating a very low tuned vented enclosure, you need to create a vent that is long enough to support the incredibly long wavelengths (that I am for some strange reason going for), by keeping "out of phase waves" from the rear of the speaker from negatively interacting with the "in phase" waves coming from the front.
From my understanding, this is only done by allowing enough time to pass for the "in phase" wave eminating from the front of the speaker to oscilate and become better aligned with the wave coming from the port.

The only way to do this that I can presently concieve of is to create a vent long enough for these long wavefronts to better align themselves, i.e. T-line.

I can see how certain types of more conventional ports could increase internal air pressure by restricting the flow of molecules, thus creating a higher velocity, and shortening the time elapse requirements of the rear-of-cone wave front. But I believe that this would add a variable that might be incredibly difficult to analyze by increasing back pressure on the cone. Anyone well versed in fluid dynamics?

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.

NissanKicker obviously has no idea what you're talking about, nor how to properly model a sub system for use in a car. He seems to not understand the effects of cabin gain and why an F3 of 50hz in no way keeps the system from reproducing frequencies well below that with authority from a sealed system while the same cannot be said about most ported setups below tuning.

Since you really just want to hear the low stuff and not really be abused by it, a decent sized sealed box with moderate power should get you where you want to be or at least as close as you'll get with that sub. More cone are or excursion capability or both would help you out a lot towards your goal, though.

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.