# Disadvantages of running too small of a ported enclosure



## spork (Jul 1, 2008)

Hello everybody, 

I understand what happens and I know the effect on the driver when it is run in too small of a sealed box, but what about too small of a ported box?

What I do know is that it limits my low end extension and can potentially make port length unreasonable - but what about effects on the quality of the output?

I'm not trying to save space - I really like the efficiency and impact that a ported enclosure has to offer and I don't really need the hugely extended low end output. 

The sub is a Diamond D6 and Diamond recommends 1.25 cubic feet which is what I built a while back and it is very very strong on the low end - when I later modeled it in winisd, it has a huge peak between 30 and 45hz. WinISD recommends .825 cubic feet and I was liking the curve of something like .55 tuned to 33 - but I've never really even considered running a ported box SO small









Light blue is the Diamond recommended enclosure
Yellow is sealed
Green is the .55 that I seem to have an interest in.

Cabin gain in my vehicle will take care of me in the 30 - 40 region, so I'm not worried about losing output there. 

SO, back to the original question, what are the downsides to running a ported box that small aside from the ones that I already mentioned?

(just in case your wondering, heres a link to the subwoofers tech sheet. I have the D4 10" D6 Tech sheet)


Thanks!


----------



## chad (Jun 30, 2005)

I like the curve too, but keep in mind that the vent will be HUGE.


----------



## 12vTools (Jan 15, 2009)

with the huge vent you will have to add that volume to the displacement of the enclosure unless the vent is outside of the box


Also I wonder about large amounts of group delay and what the effect will be .

Damn I miss Peter W. Mitchell


----------



## chad (Jun 30, 2005)

It's not that bad (group delay) I use a .7Ft^3 box tuned to 30 and at my XO frequency the delay is VERY doable, but I cross higher than many. If you are going to do it it's wise to use a low distortion driver, if it's a noise maker THEN you will have a noticeable issue with group delay IMHO.


----------



## thehatedguy (May 4, 2007)

I think smaller ported has less group delay than larger.


----------



## chad (Jun 30, 2005)

thehatedguy said:


> I think smaller ported has less group delay than larger.


It is smaller but the Q of the Group delay curve is much broader in smaller enclosures.

Granted where the big difference is resides well below the tuning freq where you really won't be playing it anyway but excluding the tuning freq, the delay for the smaller box is greater above tuning than that of the larger box.


----------



## spork (Jul 1, 2008)

Thanks for the replies,

I think I will go ahead and give it a shot. Hopefully it will work out


----------



## thehatedguy (May 4, 2007)

I think if you are under 20msec at 20 hz, you are pretty good.


----------



## spork (Jul 1, 2008)

So I built it, but haven't had a chance to listen to it yet.
I'm getting a little nervous, though - because I keep hearing that "too small" of a vented box will be muddy and boomy, although I can't imagine that it will be with the curve that winisd shows. Only listening to it will really tell.


----------



## Oliver (Jun 25, 2007)

Other than it will sound like *ASS* , you should be fine and hey ! You have more experience building boxes now 

It will sound much better in the recommended box volume or a touch bigger


----------



## spork (Jul 1, 2008)

I'm sure it will be much better than the "recommended" as recommended was absolutely terrible, sloppy, overly exaggerated low-end, etc.

Although, I have the same prediction that it would be better in a bit larger enclosure, but we will see.


----------



## Lanson (Jan 9, 2007)

I have on more than one occasion made a bad ported box, which then turned out to be a very good sealed box with just a few quick alterations!

Always good to have a plan B.


----------



## 94VG30DE (Nov 28, 2007)

I actually turned my last sealed box into a ported box with some PVC and had great results!


----------



## billg1230 (Jul 17, 2009)

Another disadvantage of the small ported enclosure is the port length.
Unless you want it to look like Blue Man Group is setting up for a show in your trunk LOL.


----------



## Patrick Bateman (Sep 11, 2006)

In twenty years of building boxes I've never built a single ported or bandpass box that performed like the sims said it would. I believe this is one of the reasons so many people like sealed boxes - they're difficult to screw up. I've had to reduce vent lengths by as much as 50% to get the tuning frequency of a ported box correct.

They can pry my WT3 out of my cold dead hands.


----------



## chad (Jun 30, 2005)

Patrick Bateman said:


> They can pry my WT3 out of my cold dead hands.


that's on my gift list for the holidays.

I have been known to sweep a cab and watch the driver... git-er-dun.


----------



## chad (Jun 30, 2005)

billg1230 said:


> Another disadvantage of the small ported enclosure is the port length.
> Unless you want it to look like Blue Man Group is setting up for a show in your trunk LOL.


hey now 

it was just an experimental thing :blush:


----------



## Brian Steele (Jun 1, 2007)

spork said:


> Hello everybody,
> 
> I understand what happens and I know the effect on the driver when it is run in too small of a sealed box, but what about too small of a ported box?


I think you should be fine. I've built a few vented boxes for car audio use, and in almost all cases I took my cues from the predicted response curve (including the car's transfer function), vent requirements and excursion predictions, rather than the "standard" alignments (which almost always result in a larger box). I was quite happy with all of them.


----------



## 94VG30DE (Nov 28, 2007)

billg1230 said:


> Unless you want it to look like Blue Man Group is setting up for a show in your trunk LOL.


I happen to like the blue-man group, and that box took me 15 min to build. So hush :laugh:


----------



## billg1230 (Jul 17, 2009)

Haha. I love Blue Man Group. I saw them live about ten years ago at the Charles Theater in Boston... Incredible. I highly suggest seeing their show if at all possible!


----------



## kyheng (Jan 31, 2007)

Depending on situations, if not using TA, you will be in trouble. The bass will "fly" above your head. This is what I experienced last time. 
And another example is recently I listen to a setup which using Boston G5 with the enclosure 50% from its recommended volume and I don't fell any solid bass.


----------



## savagebee (Sep 12, 2006)

kyheng said:


> Depending on situations, if not using TA, you will be in trouble. The bass will "fly" above your head. This is what I experienced last time


can you describe this differently?


----------



## kyheng (Jan 31, 2007)

As that is feeling, it is hard to tell clearly. But for me, a woofer's bass should hit highest is your chest only, the best is hitting your stomach. Bass is for us to feel, not listen to it. That's the thing I can feel/listen when the enclosure is too small.


----------

