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Discussion Starter #1
Other than for practical purposes, can a ported box be too big?

My Opti1232d does not offer a lot in the way of t/s data.
Lanzar's suggested ported box is quite small, with a very small port (3") given the capability of the sub.

WinISD Pro indicated something much larger, tuned several hz lower would offer better response.

Is there anything inherent about the resulting performance of the sub by going with a much larger than recommended box? Assuming, of course, the port is sized correctly for the desired Fb and air velocity.
 

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what a good box program will suggest for good SQ VS what the manufacture suggests for the masses are ussually two different things.
 

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you will notice that as you increase volume the vent shrinks... shrinks to that of the thickness of the wood, at which point you have to start making the vent larger and larger....

So in theory yes, it can be too big when you get to the point where the vent area cannot properly tune the enclosure with a simple hole in the enclosure.
 

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Discussion Starter #6
I have two of these subs. One is being used for HT, the other in my car.

The HT sub is in about 4cf tuned to around 25hz IIRC. I love the way it sounds, for movies and music.

In the car, however - it's in 2.7 tuned to around 28. I like what I get out of it in the 30's and 40's, but it is useless at about 60+.

I have a decent set of components getting plenty of power, but overall it's really lacking in that 60-80 range.

Basically, I'm trying to figure out if the sub's lack of output in the upper sub range has to do with the enclosure size, or if it's to be expected from a 12 that can dip into the 20's and still give me some output.
 

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( I read once that Tom Waits put piano strings on a dumpster )
 

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I have two of these subs. One is being used for HT, the other in my car.

The HT sub is in about 4cf tuned to around 25hz IIRC. I love the way it sounds, for movies and music.

In the car, however - it's in 2.7 tuned to around 28. I like what I get out of it in the 30's and 40's, but it is useless at about 60+.

I have a decent set of components getting plenty of power, but overall it's really lacking in that 60-80 range.

Basically, I'm trying to figure out if the sub's lack of output in the upper sub range has to do with the enclosure size, or if it's to be expected from a 12 that can dip into the 20's and still give me some output.
In the car with cabn gain, you have a HUGE peak at 30-50Hz, so I'd say that your sub isn't lacking at 60-80, it just doesn't benefit from the massive peak. Try reducing the peak with an EQ and increasing the gain on the amp. You'll reduce excursion and distortion between 30-50 and you'll have plenty of amp power left over.
 

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Discussion Starter #13
This is an old old post, but I was just looking through some of my old stuff and wanted to reply since I eventually discovered the problem. I got some good info here, but as usual the problem was just a result of me being dumb.

I was pretty embarrassed when I realized what it was...my component amp was out of phase with my sub amp (or vice versa, whatever) so in that 60-80 range where the comps were interacting with the sub it was dead.
I turned the phase dial on my sub amp -- problem solved.
I let it run like that for a year, maybe more.

:embarassed:
 

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You revived a 3 year old thread to say something completely irrelevant? Good job
 

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I'm glad to see it was resolved. It shows that sometimes it's the simplest things that we overlook. I've had sort of the same thing where I had my midbasses cranked up with only moderate output despite being 9" with 300w each available. . By muting the subs it got better. By muting each midbass separately it got a lot better. Obviously I had some serious TA problems and it allowed me to turn the gains way down on the midbass and remove the upper end boost on the subs. It was enough to cure the light dimming I was getting on the bass (not subbass) "hits" that the subs and midbass shared.
 
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