[Bass&Trouble]

I dont see the fuss about using a ported enclosure with 1200W rms. Build the box well, choose a correct tuning frequency, and I doubt you'll cause any damage to the woofer.

[low_bass_makker]

Originally Posted by Bass&Trouble

I dont see the fuss about using a ported enclosure with 1200W rms. Build the box well, choose a correct tuning frequency, and I doubt you'll cause any damage to the woofer.

ya sir...also one thing I have observed is that in a sealed box the woofer diaphragm moves more....when compared to a ported one in normal usage or I can say above the ported tuned freq.......I think this is cause because of the air in the sealed box act as a spring which causes the diaphragm to spring back....but in a ported the air from the back is free to move outside and add to the sound or SPL......also I have practically tried this with my older pioneer subs which had ports...I closed the port of one sub and I saw that the one with port closed was moving more than with the port open.......

and every time I end up with a ported enclousre ............

[Autophile]

No need to go ported, Sealed will give you better response and the boxes will also be smaller, all you need is a good tuning and correct box volume.

If at all you want to go ported, go for slot port enclosures.

[navin]

Bass reflex is usually more efficient than sealed but sealed boxes offer tighter bass besides I find that room gain (ok most of my knowledge is from home audio) quite nearly compesates for the roll off of a sealed sub so you can gain about 1/2 octave of extention without getting BOOM by proper sub placement.

On the flip side bass reflex boxes can offer great "slam". My JBLs (2245) were in ported boxes (B460) and boy they could rattle glass, nerves, and sometimes even the walls (esp when playing 1812).

[WoodenKnight]

My impression is that if you're looking for SQ, sealed is a better choice, especially if you have the amp to drive the sub since it gives a far better reproduction (or am I reading the frequency response charts all wrong?).

The bit about what parts moves how much should have little bearing in normal circumstances because in ICE setups you will not be driving the subs hard for most of their lives. So the argument of if it moves too much the less its life does not hold much water. In my plebian thinking, my poor little mind argues that any system needs to move the same to produce the same volume/quality for the same frequency; it's just different how good it is from recovering from the previous frequency played at a certain volume to play the next (response time?) and obviously with the freedom that vented enclosures provide, a sub will find it easier to do that and stress the amp just a bit less than what would happen in sealed enclosures. But lbm, in your setup (or as high-quality ones) -- you should not be worried about all that -- just worry about the SQ and that's what sealed will give you (unless of course all you want is more of SPL).

[Bass&Trouble]

Originally Posted by WoodenKnight

My impression is that if you're looking for SQ, sealed is a better choice, especially if you have the amp to drive the sub since it gives a far better reproduction (or am I reading the frequency response charts all wrong?).

Just reading the frequency response charts is not sufficient to determine sealed vs ported. By frequency response chart, I assume you mean the plot of the subwoofer driver as measured in free-air without an enclosure. Efficiency bandwidth product (EBP) as obtained from the T-S parameters determine which of the two enclosures would be more practical for a flat response.

Originally Posted by WoodenKnight[B

][/b]
The bit about what parts moves how much should have little bearing in normal circumstances because in ICE setups you will not be driving the subs hard for most of their lives. So the argument of if it moves too much the less its life does not hold much water. In my plebian thinking, my poor little mind argues that any system needs to move the same to produce the same volume/quality for the same frequency; it's just different how good it is from recovering from the previous frequency played at a certain volume to play the next (response time?) and obviously with the freedom that vented enclosures provide, a sub will find it easier to do that and stress the amp just a bit less than what would happen in sealed enclosures. But lbm, in your setup (or as high-quality ones) -- you should not be worried about all that -- just worry about the SQ and that's what sealed will give you (unless of course all you want is more of SPL).

A vented enclosure does not completely compromise the restoration effect of a sealed box. The sub will go haywire only below resonance. You are right about bass being proportional to cone travel if the radiating area is the same. However there are factors like linearity of the excursion and cone flexure also in addition to impulse response time.

Use of vented enclosures for spl is done with zero regard to sound quality. Vented enclosures used for SQ application are intended to flatten the response by introducing the rear wave's output in a region where the sub's front wave response is dipping. I suggested a ported enclosure to LBM only from that point of view. However, I gather from Autophile's post, that it is not required with the driver in concern, so I assume that using a port might in fact cause an imbalance, and considering Autophile's experience with ID products, I am not going to contest that.

[low_bass_makker]

some good installed I have seen on the net take a huge enclosure and tuned them to close to 30 hz...this is what I have seen.....Also I dont agree that a sealed enclosure will give you SQ and a ported one will give SPL.....If made properly a Ported enclousre can also produce nice SQ.....with giving more flater response when compared to the sealed one.....right now I am playing with WinISD to finialize the box volume to which one to go for.....firstly I am going to see that what the present box is offering and then compare with the result of the software........major chances is that I will go for a ported one......

[gunbir]

Originally Posted by low_bass_makker

some good installed I have seen on the net take a huge enclosure and tuned them to close to 30 hz...this is what I have seen.....Also I dont agree that a sealed enclosure will give you SQ and a ported one will give SPL.....If made properly a Ported enclousre can also produce nice SQ.....with giving more flater response when compared to the sealed one.....right now I am playing with WinISD to finialize the box volume to which one to go for.....firstly I am going to see that what the present box is offering and then compare with the result of the software........major chances is that I will go for a ported one......

LBM, all said and done, its your car, your ICE, your decision. The problem for me is that I can't imagine the need for more loudness in a hatch with 2x iDMax with 1200w on each. I really can't. Most of our iDMax customers cars get crazy loud with 400~600w on a sub. And these are sedans, SUVs! If something isn't right with your setup as it is, I think you are looking for the solution in the wrong direction.

[low_bass_makker]

Originally Posted by gunbir

LBM, all said and done, its your car, your ICE, your decision. The problem for me is that I can't imagine the need for more loudness in a hatch with 2x iDMax with 1200w on each. I really can't. Most of our iDMax customers cars get crazy loud with 400~600w on a sub. And these are sedans, SUVs! If something isn't right with your setup as it is, I think you are looking for the solution in the wrong direction.

I agree with you that the subs get crazy loud on 400-600 watts power......but I am doing some thing different.....there is some confusion.....will discuss about it a bit later....

[sk456]

2x ID Max on 1200 watts of steg power on each.....thats LOUUUD man.....

I recently had a chance to hear Rainbow Vandium Subs with Sinfoni Amps ...beautiful... they were in a sedan... You could just hear a hint of the bass ...jsut right... it was a SQ car though....( I heard tons more...but thats another thread altogether.. was fortunate enough to be at a SQ Comp with about 50 cars... )

[navin]

LBM,
a) first determine how loud do you need it.
b) it makes good sense to determine your max SPL first becuase if that need is satisfied with a sealed box why go ported. ported boxes CAN provide SQ (no need to convince me on that - I have built many ported subs and midbasses) but it is slightly more diffcult to tune and there is the question of "decoupling below resonance".

B&T,
Many subs have EBPs that allow sealed or ported boxes. Manufacturers have got that down to a science. However instead of only considering at freq. resp. and impluse response charts and T/S numbers my method involves actually builing the damn boxes and listening. Some woofers just sound better in ported boxes (many Focals or JBLs for example) and some in selaed (many Dynaudio for example). Disclaimer: my knowledge is vintage so newer drivers might prove this to be untrue.

SK,
Rainbow is ok but you got to hear Sinfoni! Now I am jealous.

[Autophile]

LBM the low freq tuned ported boxes required for ID Max's are not small and to get the best results you have to make slot port boxes. The two of them under no circumstances will fit in your swift boot.

Lastly my advice to you is stick to sealed and spend time and effort in tuning your system (amplifiers, EQ, TA etc).

[Autophile]

I will avoid to use posted enclosures with high excursion subs until and unless I want to knock out every one in SPL competition.

[low_bass_makker]

So today I am going to try a ported box......let us see what would be the results....will be posting them later tonight......

[navin]

LBM if it is extension you are looking at since you have 1200W on tap why not try a Linkwitz Transform?