ported or sealed or bandpass...

[wulff]

I have 2 Crossfire 12" CF212 dual coil subs and a California Profile AP1200 2-channel amp and need some expert opinions.

First, what I want:

I listen to Rock like Van Halen, Scorpions, Aerosmith, etc. as well as mild stuff like Greenday, etc. but no rap.

I like the bass loud with good SQ but not so it no longer sounds like it is not a recording of real instruments.. you know, I want it to sound kinda like a live concert with loud bass but not exaggerated.

Crossfires recommendation for these subs:

Model: CF212D

Enclosure (cu. ft.) Reference Box "Q" Tune to Port

1.26 sealed Small 1.1 - -

1.7 sealed Optimum .99 - -

2.52 sealed Maximum .85 - -

2.0 ported Rap & Rock - 28.4 Hz 4 x 17.9

2.4 ported All around - 26.7 Hz 4 x 16.75

2.8 ported Low extension - 25 Hz 4 x 16.25

Bandpass

1.3 Vr, 1.49 Vf All around 1.11 63 Hz (2)4 x 7.25

.95 Vr, 1.85 Vf High output 1.27 64.3 Hz (2)4 x 4.6

1.61 Vr, 1.54 Vf Audiophile 1.03 62.1 Hz (2)4 x 7.2

A CF212(D) has a displacement of .061 cubic feet so adjust accordingly, also all Crossfire CF2 speaker enclosures recommendations have been designed with the use of damping material

----------------------------------------------

It seems like all the "pre-made" sealed boxes are 1.25 or smaller and they are recommending around 2.0

So based on this info and the kind of music I listen to and the SQ I like.. what enclosure would you recommend?

Also, this chart tells me the vol of the different boxes but not the diminsions to build or buy one... is there a chart that you can punch in the vol numbers to get the dims? All the ones I find has you putting in the dim and it tells you what the v is, why not the other way around?

Sorry for the long post. //content.invisioncic.com/y282845/emoticons/crazy.gif.c13912c32de98515d3142759a824dae7.gif

Click to read more...

 

[vasilios 10+ year member]

in general for any sq system i would recommend sealed; very tight, accurate, superb sq, and also offers the widest frequency range.

then again i listen to mostly metal/classic rock/some bass-cds/no rap and i have a xxx15 in a 4^3 ported box tuned to 30Hz with 1300 watts going to it..sounds good to me, go figure.

 

[60ndown 10+ year member]

you could 'clamshell' your 2 subs in a pre made box,it will give you the best sq at the expense of some spl? or build or have built a 2 cube box?

 

[DJ_Mittens 10+ year member]

It's not that simple making a bandpass enclosure. They're incredibly sensitive to the dynamics of the individual drivers and the application they're used in. If designed properly, they're the best of both sealed and ported. If designed poorly, they sound like a fart can.

For rock, I like a sealed enclosure. It makes the kick drums sound very crisp and tight. Ported softens the drum kicks a bit. It depends on what you want. Ported would give you a little bit better efficiency from the system, and at low-moderate volumes, will sound very similar to sealed. I have a sealed enclosure in my car, and a ported enclosure for my house. Both seem to blend in perfectly with the music you describe.

So, the things to factor in are this. Space needed by the subs, space available, and power available. For your application, I'd choose ported. That's not a huge amount of power being put out by that system, and it could use the help from the increased efficiency of a well-built ported enclosure.

 

[Ignatowski 5,000+ posts]

sealed for rock

ported for rap

 

[diminishedpower 10+ year member]

maybe its just me but i've always felt that ported box that wasnt huge and tuned low had the same response and sound as a sealed for like the drums but with the extra output.

 

[DJ Kontakt 10+ year member]

ported lol

 

[DFW40 10+ year member]

For true rock I would go with large ported tuned to 35 hz. Sealed is fine but I have a Brahma 12 with 1200 watts sealed.... I also have a ported box and ported is much better for rock IMO. 1 ported or 2 sealed.....you tell me...if I had the $$ and the alt. and the space sealed is fine but if you do not.. ported is the way to go. A 12 inch supersub ported should be enough if built right.

 

[stones 10+ year member]

I didn't write this but I think it explains things pretty well.

4.4 Which enclosure type is right for me? [iDB, DK]

======================================================

This answer is not designed to tell you exactly what kind of enclosure

to build, but rather to give an idea of the advantages and

disadvantages to the simple configurations (Infinite baffle [1st

order], Sealed [2nd order], Ported [4th order] and basic bandpass).

Building and designing more complicated systems (order > 4) is not for

the light at heart.

4.4.1 Infinite Baffle ("free-air")

-----------------------------------

* Advantages...

- No box necessary!

- This means it's usually cheaper to design and implement

in your system

* Disadvantages...

- Requires that a good seal be obtained between front and

rear of driver. In a car, this can be quite difficult and

may require the installer to remove trim panels to plug any

holes that would let energy "bleed through".

- The responsibility for damping cone motion rests solely

on the driver's suspension. As fatigue sets in, this becomes

a critical issue in infinite baffle set-ups.

- Less efficient in the sub-bass region than above

mentioned enclosures.

- Potentially more expensive drivers than good boxable

woofer - The suspension must be extremely hearty and

long-lasting to withstand high power applications.

4.4.2 Sealed Box

-----------------

* Advantages...

- Small enclosure volumes

- Shallow (12 dB/Octave) roll off on low end

- Excellent power handling at extremely low frequencies

- Excellent transient response/ group delay

characteristics

- Easy to build and design

- Forgiving of design and construction errors

* Disadvantages...

- Not particularly efficient

- Marginal power handling in upper bass frequencies

- Increased distortion in upper bass over ported design

- When using high power and small box, magnet structure

is not in an ideal cooling environment

4.4.3 Ported Box

-----------------

* Advantages...

- 3-4 dB more efficient overall than sealed design

- Handles upper bass frequencies better with less

distortion

- Magnet is in good cooling environment

- When properly designed, a ported box will slaughter a

sealed in terms of low frequency extension

* Disadvantages...

- Size (not so critical outside the mobile environment)

- Woofer unloads below Fb

- More difficult to design/ can result in boomy, nasty

sounding bass if misaligned

4.4.4 Bandpass Box

-------------------

* Advantages...

- When properly designed and implemented, can provide

superior LF extension and efficiency.

- Cone motion is controlled more and therefore mechanical

power handling is increased.

- Cones are physically protected from contents of trunk

flying around.

- Output is easily channeled directly into the interior

of sedans.

* Disadvantages...

- Difficult to build (not recommended for newbies), and

very sensitive to misalignment due to calculation or

construction errors.

- Their characteristic filtering often masks any

distortion that occurs as a result of amplifier clipping or

overexcursion and thus will give the user no warning that the

driver is over-stressed and about to fail.

- Need substantial mid-bass reinforcement to make up for

narrow bandwidths in efficient alignments.

- Transient response is largely dependent upon the

alignment chosen....wider bandwidths will result in sloppier

performance, narrower bandwidths (and thus higher effiencies)

result in better transient performance.

- They can oft times be quite large.