My 15" XXX SEALED BOX review

[snb778 5,000+ posts]

why did everyone tell me with my 4 12's that my trunk was getting choked off because my subs were firing into my trunk top about 4 inches away.....everyone has said that firing your subs directly at a panel is bad and they are not supposed to be right against the door, or trunk wall......?? but ill give it a try. right now its just facing up

 

[VereChronicus 10+ year member]

If this is still on a seat bottom...you'll notice a large difference in impact also if you bolted the box down to the chassis where no large amount of vibration can occur. It's like in a home audio system, why good companies put spikes on the cabinet bottoms to decouple from the absorbing carpet and firmly plant the sub against the floor beneath the sub enclosure. Makes it louder with more feel transmitted through the floor into the listener via shoes or chair.

 

[audioholic 5,000+ posts]

I do not see anywhere in your explaination how front loading will increase the sub's "punchiness". Puncy bass is upper bass (midbass), not low bass. In most situations front loading the sub will increase low-end output (due to wave reinforcement) rather than increase upper extension. If you'd care to explain how this might occur, Id be glad to listen.

Also, bolting the enclosure down is a good idea, I agree. But agin, this helps transmit low-end material to the chassis (and ultimately to your body) rather than upper bass. Also, when you attach a speaker/enclosure rigidly to a surface (floor, chassis, etc) you are coupling it to the surface, not decoupling it. To decouple is to isolate the speaker/enclosure from its mounting surface as much as possible to eradicate unwanted resonances (such as in a door panel).

Lastly, you still have not explained how you feel this sub requires front loading to perform well, which was the basis of my arguement to begin with. I am not arguing against the benefits of front loaidng, merely the idea any particular sub needs this to perform well.

The 'whatever man' comment was for your condescending attitude, while not explaining your arguement what so ever.

 

[VereChronicus 10+ year member]

And what specifically is the attitude you are giving now?

Decoupling from the carpet, Coupling to the floor beneath it. READ before you open your e-mouth and look retarded doing so. That was rude, but it had to be said. I'm sure you can forgive MY inability to come up with a more refined way of saying "read twice answer once."

Explanation: since I'm sure I have your attention now, or maybe I just made you blindly skip this part so you can dash to the "retort" button, hmm?

Bolting an enclosure transmits all frequencies that are played through that system into the chassis, where you came up with the theory that it only transmits low frequencies is beyond comprehension. Punchy bass is in reference to the energy of the subwoofer stopping and starting within a close vacinity to said panel to transfer more of that energy through the interior of the vehicle. Front loading the sub will raise the effective mechanical Q, since you are omnipotent I'll let you fill in what raising the Q does.

Punchy bass is a term that has no real definition. It is a term that is used in probably no less than 30 different ways within audio based discussion. My definition of punchy is felt through your spine; something that attacks your lungs. Within that definition, you can get "punchiness" with a wickedly applied 20Hz note. It is easier to get punchiness at a higher note (to a point ofcoarse) than with a low note, but we have already established this subwoofers inability to deliver upper bass performance have we not?

It is not just the front loading of This or That sub. Its A sub. Hemisphere reduction translated into output increase is law, not theory. How you are recreating in your head what is being typed is up to you, not me. The way you take "front loading" is entirely up to you as well. You seem to have a single idea as to how this is accomplished. But, beyond the debate, you'll see what the outcome is when the guy comes back with his answer and it IS more punchy to him. By loading the sub against the door, as compared to loading it against nothing, it should be obvious to someone experienced what it will do.

Lastly, as stated above, Condescending is only in the eyes of the beholder. In other words, YOU took it that way. It has very little to do with me. The way you conducted yourself leads me to turn my head in another direction. I normally can sence when I'm talking to a brick wall and I have not recently made that mistake two times in a row. If you read up on hemisphere reduction as was suggested, which I believe YOU would certainly take as a COMMAND or something, thereby getting flame red and worked up, it would have simply explained everything. My interest is not to come in and argue with you, rather to guide the questioning thread starter in the right direction. If you have something negative or contradictive to say to me, that does not seem to have much place in the original thread. Beam me a PM or something with caustic remarks but I hope you understand that I cannot help the way you take remarks. People that take offense as easily as you tend to have their own problems that they cast upon others. In psychiatry it's called a defense mechanism.

 

[VereChronicus 10+ year member]

There was once a moderator that took offense to something I said that was most certainly not aimed at doing so. Hence the cute little red mark I have under my screen name. See I do realize my participation on a given forum is up to how a moderator is feeling that day. He was flaming the thread owner with some "way over the head" information that was basically bashing him and I took enough offense to it to state it in the forum. I got a red dot reprimand and he cooled down and understood where I was coming from and stopped the caustic commentary. S'what happens in the judicial system.

 

[VereChronicus 10+ year member]

Another thing, what sign over my head gives you the urge to believe "and type" that you have way more experience than I do at anything? Please read it a few times before you take offense to it and then reply if you will. I'm interested in this concept as well as you were mine.

 

[snb778 5,000+ posts]

ok, so VereChronicus..I have to understand something.....cause what your telling me is against everything ive ever heard, as far as putting the sub RIGHT NEXT to a panel or wall in my car......so your telling me that if i wanted to put say 4 10's in my trunk, to get them to sound punchy, i could mount all of them basically right against the back of my trunk....facing the back of the car.....isnt that why we have the term..."choking the subs"

cause in my last setup, i had 4 12's facing the top of the trunk, mounted probably 4-6 inches away from the trunk lid when closed, and it wasnt as loud as it should have been....lots of people told me it was because "they were gettin choked, and to close to the trunk lid"....now im just gettin confused.

 

[VereChronicus 10+ year member]

That is a great way of thinking for a first shot! Their are always contingencies such as how much that panel flexes, driver location in relation to the panel, shape of the panel, driver location in relation to one another or the port etc. etc. I just saw someone's avatar that had 4 or 6 subs firing up that looked as though the enclosure started close to the trunk rear wall and went clear through the rear seat-back opening. Then you have massive amounts of cancellation as 4 of them are loaded against a near wall...in that case being a less than effective trunk lid and the front 2 of them firing straight up into the interior unloaded. The main cause of lower output in that case as compared to maybe a good pair in the trunk in a vented enclosure all loaded against the rear of the trunk, how close depending on the size of the vent and where that guy wants his wavelengths to match up in the vehicle for an SPL #. But when you have waves bouncing all over the trunk, you effectively get an out of phase jumble in the cabin. Yes, they are all in phase within their initial enclosure but the different front wavelengths throughout the cabin never really line up anywhere. He could possibly rotate the box 4 degrees and get more lined up waves at say the kick panel and there it might register a higher number but to the ear it would be the same at the drivers position. You can "choke a sub" if the remaining hemisphere is too close for that application. It is very hard to try to give too many instances in one post I hope you understand. But we'll try another just for good luck.... Let's use large SUVs as an instance. We've done many hundreds of them with pairs of 15's and multiple 1000w+ amplifiers on each pair. Most probably left the facility with 2) 9515s and a quad of Memphis 1000ds around the boom time of 1999 and 2000. We did over 150 of those in 2000 between suburbans, navigators, yukons, escalades and excursions. So, not for bragging rights or purposes, we had tons of experience with those vehicles. We still experimented with sealed two tens combos and all that when we had time to do so. Documentation was made in many instances for store database purposes. When people wanted pavement pounders that could be heard 1 mile away depending on the drivers used we knew how much vent could effectively be pushed by those subs. If they were pissed off subs, we could use more vent and fire everything facing up....when we did that, ofcoarse we could cut off a hemisphere by putting the box ALL the way to the back of the vehicle with no "trough" room behind the box. When people used weaker, cheaper subs that could not effectively handle a big vent, we would use a rear firing setup in a closer vacinity to the tailgate to retain impact or punchiness as well as give a small loading advantage to the suspension of the drivers that could not handle an up-firing system far away from any loading wall and stand any chance of long term survival. When the customer wanted to have his heart pissed off at him and his heart doctor happy with us, in other words could give a piss less about anyone outside of the vehicle, just have it hit as hard to him...chest...ears...windshield flexing like a deflicted body-builder....that was time for no compromise subs, no compromise power, no compromise power supply and a no compromise box. If the back had room, we rear fired it into the tailgate and used retarded port area upward of 300+ square inches and 16+ net cubic feet daily driver subwoofer enclosures. NOTE: there is tons of casino and oil money here, so their kids tend to be quite eccentric in their purchases. Those vehicles do medium/high 156's-159's on the dash at 40Hz but would beat your *ss to sleep in the front seats. If we had taken the second row of seats out and scooted the subs further away ( more than 8" ) the impact went drastically down but may have scored a higher SPL # on the dash. The owners did not care about that, rather that they could tear up their side view mirrors and see an inch wide beam of light coming from between the back doors if they had those on a sick note.

Your vehicle is a tad different because you have it sitting in the rear seat with the opening to the trunk wide open via no seat-back. If you somewhat cut off that hemisphere as well, by putting the seat-back in place again, you should get more output and impact again at your listening point because very little of the energy is bleeding to the rear of the car. Tell me if that is enough information to give you a good overview of the way that works. If you need more instances, I can share them.

 

[audioholic 5,000+ posts]

Vere, you are something else. I asked you to explain your position, and your reply was basically 'hemispherical reduction, if you dont know it I suggesting reading up on it before making suggestions for subwoofer applications'. Aparently I am not allowed to recommend subwoofers or their application without knowing "hemispherical reduction" to your satisfaction? But now I am to believe I merely took it that way, that Im being defensive. If you are going to make a snide comment, at least have the balls to stand up and admit it afterwards.

And, I find your delusion of taking the maturity high road in this debate laughable, seeing as your replies to me are filled with comments such as "since I'm sure I have your attention now, or maybe I just made you blindly skip this part so you can dash to the "retort" button, hmm?" and "READ before you open your e-mouth and look retarded doing so. That was rude, but it had to be said". You seem to think you can crawl under my skin so easily, I'll assure you I've had my balls busted much worse, by much better men than you. *yawn* Most people on the net would tell you to 'stfu' or cuss you to high heaven right about now, am I doing any of those sorts of things? Yet here you are throwing around insult after insult, all the while playing the mature one here. If you'd like to keep this debate civil, Id be glad to continue, but leave the remarks based on ignorance of me or my motives out of it.

since you are omnipotent I'll let you...

Its funny you act like IM being the know-it-all here. //content.invisioncic.com/y282845/emoticons/rolleyes.gif.c1fef805e9d1464d377451cd5bc18bfb.gif For the most part Ive simply asked you to explain your position further, rather than talk down to me. How's this for acting omnipotent: you are correct, I misread your meaning in coupling versus decoupling, I was wrong. And furthermore, my comment on experience was a low-point for me in this thread, as I feel I lowered myself to the level you were presenting. Your suggestion I did not have the experience to recommend subwoofers here was so off base that I responded badly. *shrug* But yes I know, Im bieng the immature punk here, right? Gonna write another 5000 word paragraph telling why I ****, and in your own words, be rude to me again?

It is not just the front loading of This or That sub. Its A sub.

That's funny, because that's exactly at the crux of my original question, which you seem to have misread. That, or you are changing your position now. Let me explain further. Your original comment which I questioned was, and I quote: "You have to load something like that to get performance out of it". My reply was "Can you explain why you feel a XXX needs to be front loaded before it will perform well?" To which you replied with your comment about 'hemispherical reduction, if you dont know it I suggest blah blah blah...". Soooooooo, my original question was why you were suggesting this sub needed to be front loaded in order to "perform well". But now, several posts and like 500 put-downs later, you say its not about the sub specifically, but any sub. Why did you not say this when I first asked about XXX's specifically? Maybe Im not the only one who misread the other...? I guess any sub needs front loading before it will perform well...? The rest of this debate has been your psycho babble trying to poke holes in me, rather than simply answering the question as its presented to you. If you feel its beneath you to explain your position beyond the two words 'hemispherical reduction', expect someone to call you on it.

Also, you can act like Im some inexperienced noob who needs to do more research before he can debate this with you, but the truth is this topic is not as black and white as you would like us to believe. Let me quote you a little something:

"jm----the effect is simple-----the reflecting surface causes a pressure buildup because the pressure front from the speaker has no where to go---when energy is thus concentrated into a smaller space than it naturally wants to be there is a pressure increase-------this happens when the wavelenghts are large relative to the reflecting surfaces----it is simply a ratio thing-----------------but the real fact about aiming speakers in a car into a corner or fender is totally misunderstood but the truth will never be accepted-----its one of those beliefs that will never be cleared up but i am going to run it by you anyway-------firing a speaker into a fender or against a surface in a car is not what causes an increase on output-----while facing a speaker close to a surface will cause a pressure increase BETWEEN THE CONE AND THE SURFACE, UNLESS YOU CAN SQUEEZE YOUR EARS INTO THAT SPACE IT WILL DO YOU NO GOOD----as soon as the sound leaves the confined space the pressure will drop to normal in the actual listening space------you cannot get something for nothing and since the waves of interest are already confined by the dimensions of the car there is nothing to be gained by "down firing" "corner loading" or fender trapping or whatever it is called------IF an output increase actually happens it is due to the actual location of the moving speaker diaphragm---------in any sealed space there are locations of high and low pressure due to the nodes and antinodes within that space----if the location of the speaker happens to be in one of the high pressure areas the speaker will see more radiation resistance and exhibit an increase in efficiency------if this happens the speaker can be turned in any direction and the output will be the same------NOTICE THAT I SAID SPEAKER and not box------if the effective high pressure area happens to be close to a surface it is not possible to turn the box around because the box will space the speaker cone away from the surface---------corner loading is right up there with amp soundquality, power wire routing, distortion hurting speakers and numerous other "installer voodoo beliefs" that will always be with us------but if we are intelligent and study the science that determines how things really work we don't have to believe such nonsense.............."

This was said/typed by Richard Clark, perhaps you've heard of him? What he said pretty much dissolves your hemispherical reduction theory creating some great change in your definition of the 'punchiness' of the bass as "nonsense". Im not saying I believe that is necessarily the case, but I am reading an alternative view, from RC who is considered one of the leaders in audio theory today, so no, Im not going to accept your 'if you dont know then go read up on it noob' attitude and go away. Again, if you'd like to present your opinion that front loading the sub in this application will guarantee this poster's happiness as you;ve suggested, or why XXX's need to be front loaded to perform well (or subs in general), as you've suggested, I'll be glad to listen. But if you want to continue trying to poke at me, rather than remain mature and debate the issue, you'll find it will become a one-way conversation fast.

Lastly, learn to use paragraphs, your posts are horribly difficult to read.

 

[VereChronicus 10+ year member]

There is a way of testing that 4 12's box you had also to verify it for yourself. Lets put the same amount of power per sub....just disconnect the front two of them. Now you have the amplifier pushing 1/2 total power to 1/2 of the subs. 1: you halved cone area which should decrease in theory 3dB. 2: you halved power which in theory should decrease another 3dB. It never really seems to double or halve your output in a near field application like a vehicle in the real world, but lets use theory to make it simple. So 2 subs and 1/2 power less than you first started, now we can only rely on the loading and position of the subwoofers to offset that drastic loss. You should find that you only really go down from 1-3dB. This means that you have to take into consideration the position of the drivers in relation to the measuring point, the nearest panels, one another etc. etc. If you open that trunk, you'll ofcoarse see that you still have big pockets of open volume behind each wheel well on either side of the box. If you were to put a panel that went from floor to the top...totally sealed off you will have, dare I say the tiring words again: cut off two more hemispheres to channel more forward into the cabin. In open field measurement, that would be a theoretical 6dB gain, but since you did not have an infinity on either side of the box, your gain could be 1dB, it could be 4dB...depends on shapes and vacinity distances. If you were able to put the total amplifier power on just those two subs with those other modifications, you could quite possibly easily outscore your four 12" setup.

 

[stones 10+ year member]

I see one person pounding their chest and trying to prove how important they are.

And another trying to help the thread starter.

Do you know which person you are?.

 

[Hundreth 10+ year member]

I see one person pounding their chest and trying to prove how important they are.And another trying to help the thread starter.

Do you know which person you are?.

//content.invisioncic.com/y282845/emoticons/popcorn.gif.32dd9e22fd77e77bc3c907062768fcd2.gif

 

[Eugenics 5,000+ posts]

//content.invisioncic.com/y282845/emoticons/popcorn.gif.32dd9e22fd77e77bc3c907062768fcd2.gif

stop instigating shit and feeding off drama. maybe make a useful post somewhere or do something other then watch shit happen

 

[tRiGgEr 5,000+ posts]

stop instigating shit and feeding off drama. maybe make a useful post somewhere or do something other then watch shit happen

I've noticed an increase in hostility in your recent posts man. Not really helping either //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

To the original poster. Untill you learn a bit of the basics in installation and proper settings. Try to not make a "review" thread.

There are so many flaws in the setup, a unbiased and educated review can not be formed from the listening environment.

tRiGgEr

 

[Hundreth 10+ year member]

stop instigating shit and feeding off drama. maybe make a useful post somewhere or do something other then watch shit happen

Drama is 80% of this forum buddy... If anyone around here loves drama... its you. So do yourself a favor and STFU. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

It just amuses me so much how you even have the audacity to call me out on that when just the other day you went all the way to "Last Reputation #6". Obnoxious prick.