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The difference between Decwares and ported/sealed (Read 4950 times)
firepinch
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The difference between Decwares and ported/sealed
01/25/08 at 04:14:23
 
Hi all!

First, I didnt find many posts in that forum and on internet which explain well how specific Decware enclosures compare against normal sealed and ported boxes. This would be great if we could see at least some graphs which compare for example a ported X subwoofer against the other Decware designs with the same subwoofer X with the same power. Because we don't have this kind of information in the website, I would like to ask you all some questions and Im gonna try to organize them in a good manner. First, the sub, power and the enclosure that I have: one 12" TC Sounds driver (TC1000), 600W rms of power, and a ported box tuned to 25 Hz (assuming that the frequency curve is fairly flat until 30 Hz before any roll off). The application is for home.

1- How can an inverted wedge enclosure compare? In home that enclosure should be really less efficient than in car, almost approaching the performance of a single sealed box.

2- How can a Deathbox 12 compare?

3- With the lowest adjustement of the insert (lowering the tuning right?), could I get good extension to the mid 20? Flat to 25 Hz in room I mean...

Now, if we have the same situation, but IN CAR so I'm changing the tuning of the ported box to 30 Hz (it will be even more efficient):

4- How can the inverted wedge enclosure compare?

5- How can a Deathbox 12 compare?

Finally, if I add another 12TC1000 + another 600W, in a ported box tuned to 25 Hz like in first, in home....

6- Would the Deathbox 12 be 2 times more powrefull becuase it has another woofer in it?

7- Would a House Wrecker be noticably better? How much?


To terminate, I have some understanding of those enclosure, but really not enough as you guessed to answer those questions. The most intriguing enclosure to me is the inverted wedge. It says that it has supposedly great gains vs a normal enclosure in car, but how much really vs a ported enclosure and how much really in home and especially in home! The rest like the Wicked One, the Deathbox and the House wrecker are some sort of bandpass design to me but they don't tell me more than that because justly, they are not EXACTLY like bandpass designs.

Thanx for all of your answers in advance! I would like to try some of these designs, but if only I could understand them better...
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« Last Edit: 01/30/08 at 19:21:00 by firepinch »  
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musgofasa
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Re: So many questions I didnt know where to post!
Reply #1 - 01/26/08 at 22:27:44
 
Welcome firepinch,

I will try to tackle some of these questions for you. Sorry I didn't see this post earlier.

First off, what you are comparing are several different enclosures for several different environments. I will start with the basic differences as they relate to your woofers in any environment (home or car).

Ported enclosures are going to be more efficient at and near the tuning frequency. Basically, you lower the excursion and take some of the load off the driver itself in that configuration. Typically what that means is a notable increase in volume near the tuning. (3-6db is common in home and more than that in car). Also typically, the ported enclosure will not have as smooth a roll-off from it's cut off. In other words, the sealed enclosure is likely to produce lower bass (provided the same size enclosure) at the cost of needing lots more power. The thing is, you can adjust the volume and porting to accommodate the lower frequencies, but you will likely sacrifice band width and SPL at higher frequencies. It becomes a game of room gain, power, personal taste.

So how do they compare? This is what I will try to give a go on.
First let's look at the different enclosures in a typical home theater or listening room.

Ported: Likely to be boomy if it isn't very large. If it is very large, it can integrate well with bigger speakers, but might lack some mid bass for integration with smaller ones. Probably the most difficult to combine with average home speakers.

Sealed: Smoother response, easier to integrate, more power hungry to get high spls than ported or band pass

Inverted wedge: Similar to sealed, but with better room interaction. Likely to have a lower cut off from natural band-pass acoustics. If sitting on carpet, a very smooth roll off and easy integration. The TC woofer is pretty versatile so this might be a good way to go.

WO: Now we get into a sealed band pass design. The WO is pretty boomy by nature with woofers like this. Great for car systems and home theaters with adjustable bass. The WO is a workhorse, it has a good natural sound with a smooth roll off, but it is definitely a bass heavy enclosure. In the 36x36 configuration will get as low as you ever need for music, but might fall just slightly shy for the super extreme lfe in some movies.

House Wrecker: Similar output to WO, but more efficient. Less power could equal more noise and it is very adjustable just be repositioning the woofers. It can play super low, super high, or just plain super loud.

Death Box: again this one is adjustable, but has a sealed side so more power to get the same spl. I would say this one isn't likely to get you the 20 or 25 hz in a home that you asked for, but sounds extremely good and is easy to integrate with the other speakers in the house.

Now for the Car!

Ported: Loudest all around. Easiest to power. Can benefit from gain of small space. With the TC woofers, this will probably get you the most bang for the buck, but can be a big box.

Sealed: Smoothest sound. Lowest extension, smallest box. Most power hungry. Least adjustable

WO: now we are cooking with gas. You can put more power on this one and take advantage of cabin gain, but the size can be an issue. 36" sounds small till you try to fit it into a vehicle

DB: terrific sound in car! This thing will give an awesome extension and roll off. Smooth output and adjustability to match the cabin gain.

HW: Too big. Unless you have a big vehicle, the HW probably isn't a good choice in a car. Not a bad choice, but not the best. It requires some breathing room to sound right. Although it can sound very smooth, I wouldn't think of it as the best (with these subs)

OK so I may have put a little of that out of place. I may have even said it a little wrong, but I think the general idea is correct.
As far as graphs, I only know one person who has those and he isn't in the game any more. Health and financial worries have taken him out of production for a while.
The DB will get you at least 3db over sealed with a single woofer. The ported will do the same. HW should get 6 over sealed in theory, but you always have to come back to the environment it is in to measure the real world results.

Now for the million dollar questions. What kind of car, what kind of room, what kind of music, competition? Is flat response more important or is SPL? Give some goals and we can probably help you reach them. It sounds like you have a great start with some good equipment.

Take care,
Robert
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firepinch
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Re: So many questions I didnt know where to post!
Reply #2 - 01/29/08 at 01:48:11
 
Thanx for this elaborated answer Robert!

I thought that I was enough clear when I said what I would like to compare, I said: "12" TC Sounds driver (TC1000), 600W rms of power, and a ported box tuned to 25 Hz (assuming that the frequency curve is fairly flat until 30 Hz before any roll off)".

But anyway, I was sure at the same time that I was not enough clear Grin so Im gonna explain more what I would like!  :D lol! So here we go:

Well... in term of frequency response, I like bass when it is flat in a large band of frequencies. I like to feel as much kick (mid-bass) than very low bass. So between 25 to 80 Hz or so, I would like it flat then under 25 Hz it can roll off.

With a ported AND sealed boxes I am able to do so in my room. I have a very small room (1500 cuft), all wooden except the ceiling. With a sealed alignment, I must use often a Qtc between 0.6 and 0.7, depending of what woofer I am playing with. With a ported box, in order to do this, I build it a bit on the small side, with a tuning of 22-25 Hz depending of what woofer I use so the frequency curve almost look like the sealed one BUT efficiency is better down low. I did a ported box like that with an Ascendant Audio Assassin 10 and it sounded almost like a sealed box but with more SPL, it was punchy and could go low at the same time, it was unbeleivable!

HOWEVER, despite the frequency curve of my ported boxes looking almost like those of my sealed boxes, its rather IMPOSSIBLE to have the same looking frequency curves for both: i.e.: 6 more dB anywhere on the top of the sealed boxe. Above 40 Hz, they begin to be different from each other so the ported boxes have less mid-bass gain.

So this is where my goal come into play! What I would like to have is a box which is more efficient than a sealed box or why not a ported box with a frequency curve which is like an "offset" of what we can see with a sealed box or a ported box so for example a 4dB gain everywhere from 25 to 80 Hz.

A PERFECT example of what I wanna say is right on the "Wicked One" page. You can see in the graph that vs a ported box, the Wicked One has more power over a WIDE frequency band. This is what Im seeking for: efficiency.

So what is my room and my car? My room oh.. I think that I said it its a 1500 cuft room, rather squarish so I use an EQ to tame the bass around 40 Hz (the famous room mode of those kind of room). Other than this peak I have, any other frequencies are almost sounding equal (+/- 1 dB!!!) except a little valley in the mid-bass region. This is perhaps because of the shape of the walls and how a window is deep vs the main back wall (so there is like a hole there). An irrigular room is often better than straight rooms which are strickly rectangular!  :)

And my car... it is a Cobalt SS Supercharged 2007. The trunk opening is small, however, inside the trunk, this is surprisingly large! I will have to see if I can squeeze 36" of "wideness" in there!

And for the kind of music, to me, it doesn't matter. Most people who listen to rap and techno like the bass more lousy and boomy and people who listen to rock like the bass dry and very tight and chest thumping (mid bass heavy) but Im not like that. I like only ONE bass, bass that is even as much at 55 Hz than it is at 25 Hz. I like to feel it as much in the chest than feeling it in my ass in home when the floor is shaking badly. I listen to about anything! So if a 40 Hz note is not enough loud in a hip hop song for example, I dont make an enclosure so the bass is more powerfull around that, instead, I just turn the subwoofer volume knob more to have the same effect, but with a kick in the chest which may come after, as much louder too!  ;)
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« Last Edit: 01/29/08 at 01:51:02 by firepinch »  
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firepinch
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Re: So many questions I didnt know where to post!
Reply #3 - 01/29/08 at 01:57:41
 
I decided to post another reply for a clearer text reading lol! Now that I described what I said and that I have read what you said... some other questions come in my mind:

The Deathbox and the Wicked One seems to be a little "brothers". Which one will be the louder and which one has the larged gain in a wide band? I guess that for the SPL in a wide band this is the Wicked One? Those are not supposed to be really louder than a ported box? Because in the Wicked One page, we can see that this enclosure has a quite big advantage vs a ported one!

You didnt tell about the inverted wedge in a car... I guess that this one is almost x dB in a large band vs a sealed box... with a lower roll off right? So almost like the output of a ported box? But not approaching the ported box output in home because the inverted wedge is less efficient in a larger space than in a car right?
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musgofasa
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Re: So many questions I didnt know where to post!
Reply #4 - 01/29/08 at 12:56:31
 
Hi Firepinch,
I see what you are after now.
I'll start with the car. The inverted wedge will have a higher SPL than a normal sealed, but will have a lower frequency range. Basically it will sound more like a larger ported box and will tune close to Fs and cabin gain. While it is a great sounding box in a car that size, it might require some eq to make it as "flat" sounding as you are asking for. The WO will likely give you more, but at the expense of a lot of space. (it's big in a trunk). The DB will likely be tuneable to the sound you are looking for. I highly recommend this box for your car.

In the house, it sounds like the HWK might be the right choice. The flexibility of tuning allows for one chamber to go low and keep the room gain tamed while the other chamber can be tuned higher to even out the pass band. A 6th order is the most flexible, but should require some fine tuning of the port size and lengths. Run some sims in WinISD and see if you can work out an attractive FR with the woofers. It won't be a perfect science till you build it and position it, but I think it sounds like the right way to go,.

Keep us posted!
Robert
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firepinch
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Re: So many questions I didnt know where to post!
Reply #5 - 01/29/08 at 20:15:33
 
Thanx for the answers again!  :D Hum still some other questions  :P What if we use TWO woofers in a Deathbox (it can have two in it) and in a House Wrecker? Will this DOUBLE the SPL considering that you give them twice the power? What will happen?

And well... I dont know if its me but I feel that some people and including you tell me that the Deathbox and a Wicked One is not that much louder than a ported box. Is that true?  :-/

If I have a good understanding of all of these enclosures, in the SPL department this should be:

Sealed < Inverted Wedge < Ported < Deathbox < Wicked One < House Wrecker?

Finally, people here seem to find that the Decware enclosures sounds really good even if many of those imply a bandpass design. I never touched very much bandpass designs, I got one in the past and it sounded justly boomy but is this not a question of FREQUENCY RESPONSE that can make subs boomy or not, bandpass or not? I think that this can explain a lot of boominess found in certain subwoofer designs... not only group delays tell us if a sub is boomy or not but also and very likely the frequency response is almost the most important thing in how a sub sounds. This is kinda what Kyle from TC Sounds explained in their forum when someone asked about boominess and group delays / inductance of a subwoofer.
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musgofasa
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Re: So many questions I didnt know where to post!
Reply #6 - 01/30/08 at 18:24:12
 
Kyle was exactly right.

Bandpass designs are not inherently more efficient than any other. Bandpass is a way to shape the frequency response to achieve a certain goal. Sealed -band pass designs are more forgiving than ported (IE 4th order vs 6th order).

Ported will be the most efficient in most cases, but not necessarily the best sounding. If you are looking for a wide frequency band that has a flat response, Ported and Band pass alignments are not going to get the job done best. If you are looking for Boom and loudness (SPL) ported and banpass can be friendly. If you want the best of both worlds, welcome to audiophile land. It is that smooth roll off and transition at listening levels that is what we all strive for.

Subwoofers are typically a different beast as most want to be able to crank them hard when they want, but prefer a more tame sound most of the time. It's a fine line.

The bottom line is that SPL is generated by more efficiency and/ or higher power. Smooth sound and good quality sound is much harder and requires a lot more "synergy" than just a good design can offer.

With the same power and same woofer, the enclosures in order of lowest SPL to highest would be:

Sealed, Inverted Wedge, Death Box,, WO, HWK, Ported

With regards to largest frequency range the order would be:

Ported, HWK, DB, WO, Inverted Wedge, Sealed

Best of Both worlds:

WO, DB, Inverted Wedge, HWK, Ported, Sealed

Kinda skews the pattern doesn't it?

Best with the TC sub and 600 W? (I think that's right, will go back to re-read)

Almost need to build each one and test, but I would say the HWK with two subs will work best in a decent sized room followed by the WO.
In a car, I would say Ported, then WO

Lots of stuff to consider before a build.

Let us know,
Robert

PS to compare the HWK and the DBII with two subs in each:
Doubling of SPL is 3db. 2 subs in a single DB should give you approximately 6db if you also double power. If all things are done correctly with the same 2 subs and the same power, the HWK should be 6db louder than the DB. Of course, environment can mean more to the gain at the mic and ear than the actual enclosure.
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Re: So many questions I didnt know where to post!
Reply #7 - 01/30/08 at 18:26:47
 
I should add,
I certainly don't mean to sound like an authority. If anyone has anything to add or change about my statements, please feel free to toss in an opinion.

I have built all of the decware subs but one and I think they all sound terrific. There are no bad designs here.

and I certainly have limited experience next to some of these guys.

I am sure there are plenty here who could elaborate better so please don't take my opinions as fact. Of course, wasting a lot of wood is a  pain,. but it can be the only way to effectively answer some questions. If you can get a test drive locally with any of the enclosures in question. that would be best.

Take care,
Robert
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firepinch
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Re: So many questions I didnt know where to post!
Reply #8 - 01/30/08 at 19:13:40
 
musgofasa wrote on 01/30/08 at 18:24:12:
With the same power and same woofer, the enclosures in order of lowest SPL to highest would be:

Sealed, Inverted Wedge, Death Box,, WO, HWK, Ported


Oh! I begin to understand more and more those designs and I like that!  :D However... I quoted above something and at first I was like why the ported alignement would be the loudest and then I thought... did you mean the highest PEAK SPL? What I wanted to imply with my enclosure in order was lowest to highest AVERAGE SPL.

I couldn't agree more that ported boxes around the tuning point have a big advantage.

I read more and more the technical datas of the Decware enclosures, keeping reading and reading again until something poped in my mind and I came to this:

When an enclosure is more efficient, its because the system uses more than the front wave of the speaker. In a ported boxe, the backwave is used and therefore, around the tuning point, you are gaining SPL.

Now, if my understanding is right, in a Deathbox, the vent is shaped so the tuning point is not at only one frequency, like a simple 4th order bandpass enclosure, but at many other frequencies (but not as much as in a horn). You can see a graph of the excursion curve somewhere in the technical data of the Deathbox. So pratically, this box is supposed to be more efficient than a ported box IN AVERAGE depending of where the insert is because when the insert is nearer the bottom of the box, you loose efficiency overall. So in that case, a ported box tuned at 20-25 Hz should be less efficient than a Deathbox around 35 to 60 Hz. Keep in mind that for SPL, Im always talking about ported boxes tuned quite pretty low, always in the 20 to 25 Hz region. A ported box however could generate sick SPL when tuned at 40-50 Hz vs a Deathbox but this is not what I'm talking about...

Now, with the Wicked One. The Wicked One is dual bandpass horn and the flare region make it so it has like several tuning points. (What I saw again in the technical data). So theorically, it should be superior to a ported box anytimes in average SPL by a good amount! I'm always comparing a ported box tuned to 20-25 Hz.

And now, about the House Wrecker. This is a kind of 6th order bandpass design. So it should give anytimes more AVERAGE efficiency anytimes vs a 4th order bandpass, and so certainly more to a certain degree than a Deathbox because you have two zones of efficiency. The back and the front chamber with a tuning point in each. So you can make the frequency response wide with it or very straight and more the bandwidth is large, more you loose SPL but still at a certain point, when the bandwidth is quite large (from 25 to 65 Hz), you still have more average SPL than a low tuned ported box. This is what I saw with WinISD when I compared a low ported box to this type of bandpass design with the SAME power with the same woofer.

And now, between the Wicked One and the House Wrecker. The Wicked One which has several resonnant frequencies vs a House Wrecker with two resonnant frequencies, I wonder if the Wicked One could not be more powerfull than a House Wrecker with for example a pair of 12" drivers (my TC1000 in occurence). I see my TC's have an Fs of 20Hz, which could be good for a downscaled House Wrecker but this low Fs couldn't be great for shaped like horn enclosure such as the Wicked One? This should give really great low end!

Finally, I said what all what I understood. So the order in which the enclosures have more AVERAGE SPL is changed now. Feel free anyone to tell me where I could be wrong, I would really like to know and understand furthurmore!

Thanx a lot lot Robert already!!! Cheesy

P.S.: I think that this will be one of the biggest tread about compact (without blah blah hey how are you goin?) technical explanations of sealed / ported vs Decware enclosures and I'm sure that I am not the only one who wants to know!  :) If any people could add some frequency responses graphes in it which compare different enclosures or any usefull infos this would be great! Just a suggestion and why not if the tread becomes that good to put it sticky!  :) Oh! And I edited the title plus... maybe later there is certainly a better place to put this topic in that in the Deathbox section!  :-/
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« Last Edit: 01/30/08 at 19:22:35 by firepinch »  
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musgofasa
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Re: The difference between Decwares and ported/sea
Reply #9 - 01/30/08 at 23:58:50
 
Dead on Firepinch

I would have to guess that in comparison, with those woofers, the WO is likely the highest average SPL. And likely it would have the smoothest integration with other speakers than the other boxes. It would be a very low tuned box so in a home, your mains would likely need to get down to the 50s or 60s (hz)

But the theories you have posted here are solid. Sounds like you have the understanding, now to put it into practice and make some sawdust! lol

Take care,
Robert
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Re: The difference between Decwares and ported/sea
Reply #10 - 01/31/08 at 06:12:47
 
I think that I'm gonna try the Deathbox 12 first. I will listen to it in home and also in car with one of my two TC1000 12" subwoofers. If I manage to like it in home, Im gonna build another one for the other woofer  :) So if I don't like it in home, I will keep it in the car and I feel that I will very probably like it in car so this is good news!  :D In home , I have some doubts with the Deathbox for low frequency extension. But we will see... I will be able to compare the deathbox with a single 12TC 1000 to a sealed enclosure I did before with two of them powered by only a 300W Bash amp for the two woofers! As well lately I had in that room corner a ported @20 Hz TC Sounds TC2000 subwoofer with a Behringer EP2500. I love TC Sounds? Absolutely!  :D Im gonna try to make a little review once I'm gonna try the Deathbox vs those subs PLUS I may incorporate the dozens of subs that I had before, built or commercial (Adire Audio, Ascendant Audio, Paradigm, Klipsch, Hsu Research, etc... to name some).

Because the Deathbox is nearer a 4th bandpass design, I will probably talk about how it compares against the Paradigm PS-1000 I had before. That one was the most impressive 10 inchers commercial bandpass sub I have ever heard. It could do 116dB around 40 to 50 Hz, can I say that it was pretty loud for the size of the woofer?  :o I very acknowledge however, it began to be poorer and poorer under 35 Hz, it didnt have high bandwidth at all and it was slow paced with rock music.  :( Now, what can a Deathbox with a 12" woofer with more power do against it!  8-)

I don't think that I'm gonna start to build the deathbox right now these days because already, I have a ported Assassin 10 subwoofer to make, powered with a 300W Bash amp, that I'm gonna sell right after. But as soon as I have finished the Deathbox, I'm gonna tell about it FOR SURE trust me!
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« Last Edit: 01/31/08 at 06:18:16 by firepinch »  
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