.707 vs .85

[jellyfish420 10+ year member]

i've been contemplating building a sealed box for my RL-p's. just to see what kinda sq these babies really got. now i wanna aim for a q of .707 right? the SS site recommends 2ft per 15, and by all the calculators i've used this is a q of right around .85, for a q of .707 i get a box of 3.25ft per 15. wouldn't the 2ft box tend to be a little peakier, and have a higher F3? what would be the advantage or disadvantage to either box? and what would you pick and why? thanks

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[squeak9798 5,000+ posts]

wouldn't the 2ft box tend to be a little peakier, and have a higher F3?

Assuming those Qtc values are correct; yes

what would be the advantage or disadvantage to either box?

Well: 2cuft would be peakier, have higher mechanical power handling, have less low frequency extension, worse transient response and group dealy, and more output

3.25cuft would have flatter frequency response, less overall output, lower mechanical power handling, better transient response and group delay and better low frequency extension

and what would you pick and why?

I'd go for .707 for the better transient response, better low frequency extension and higher efficiency

 

[80INCHES 5,000+ posts]

i'm with sqeak...i would pick the .707

but remeber the bigger the box the better the low extention and the less power u need 2 power your sub.....but u dont want to build a box to big then the sub will act as if it was in a free air situation

80

 

[jellyfish420 10+ year member]

i emailed mike @ soundsplinter and this was the response:

Both the 3.25 cu ft and the 2 cu ft net volumes will work, but in all

honesty the response difference between the two will be quite minimal.

Attached you will find the leap graph for the RL-p15 exhibiting the

relative

differences.

The Butterworth (magenta solid) box is 2.1 cu ft net volume.

The Bessel (tan dashed) box is 3.55 cu ft net volume.

The Enhanced Q (green dotted) is 0.95 cu ft net volume.

Essentially, you are asking for a comparison between the Butterworth

and

Bessel alginments, which as evidenced in the attached image, follow

each

other quite closely. I do not think that a 2 cu ft box will be much

more

peaky than a 3.25 cu ft box at all to tell you the truth.

 

[Raven 10+ year member]

That is going to make such a small difference that if you do notice it, you're doing better than I would be.

 

[jellyfish420 10+ year member]

That is going to make such a small difference that if you do notice it, you're doing better than I would be.

well it works out perfect this way. since there is no audible difference, i will be able to build it @ 3.25 sealed, and if it doesn't suit my needs then i can port that box and lower it to 2.5 ported. instead of going w/ 2 sealed and me not liking it, and having to build a whole new box //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif

 

[saywhat? 5,000+ posts]

ooooor u could build that and put on a external port on it, and add a couple 2x4's maybe to drop it down around 3 cubes, right in the median of the reccomended specs.

 

[JimJ 5,000+ posts]

t u dont want to build a box to big then the sub will act as if it was in a free air situation

I think you meant "IB situation"...and for some subs, that's perfectly alright. Elemental Designs' O series were an example of a sub that excelled in infinite baffle setups.

Remember:

IB = seperated front and backwave

Free air = front and rear waves mingle with each other (no baffle used)

 

[80INCHES 5,000+ posts]

or u could put them in a bandpass box

80

i can design one 4 u...but u have to build it

 

[chubby 10+ year member]

ew^

 

[theCybe 5,000+ posts]

( What's the difference between an IB and a Dipole? )