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Old 28th February 2014, 02:53 AM   #11
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4mm xmax ain't no sub
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Old 28th February 2014, 03:09 AM   #12
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Ummm... a whole lot depends on the mechanical stiffness of the suspension and the mass of the cone. The mass of the cone is related to the Fs figure.

A driver with a rather unstiff suspension and high Xmax will likely sag over time, how much time is where the issue is.

I've had drivers that were stored sag. Rotating them in their boxes is good practice.

The other issue with downward firing is the effect that the floor has upon the sound, and the distance to the floor... sometimes it works out well, sometimes not so well...

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Old 28th February 2014, 03:20 AM   #13
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I understand and agree. I know front vs down firing is a whole different and highly debatable topic (I'm ok with going there and discussing it here..).

I prefer the looks of front firing and sometimes feel like down firing transfers too much energy into the floor, and suffers from the effects of compression and loading if there isn't enough room under it. I just feel like mechanical driver noises are more eliminated by the floor (assuming carpet of course) and thus the sub is less localized.. I'm not worried about localizaton from cabinet resonances as the cab design will be 1.5" thick on all sides braced, but just feel the down firing is more forgiving in placement.

I also would want the front firing facing out and forward, because I'm kinda nuts with symmetry, and murphys law says then that it will sound best with the driver facing a corner so the amp and wiring will all be exposed..just because that's the opposite of how I want it..
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Old 28th February 2014, 03:24 AM   #14
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I'm recycling a car sub I have laying around for this project, JL 10w3v3-4. Seems somewhat stiff and the moving assembly seems relatively light. If anybody wants to look at the specs and give their thoughts and opinion on driver orientation or downfiring compatibility, please feel free.

10W3v3-4 - Car Audio - Subwoofer Drivers - W3v3 - JL Audio
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Old 28th February 2014, 11:49 PM   #15
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You could do like this:

Use dual drivers instead, smaller if you don't have a need for extreme SPL and build the box around them. Wired out of phase of course.

You will gain vibration cancellation which is awesome for a sub, you will also gain massive even order distortion cancellation which is even better, especially as copper rings doesn't do much in sub drivers down low. PP subs like this are awesome =)
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Old 1st March 2014, 12:03 AM   #16
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Quote:
Originally Posted by dutchess View Post
but just feel the down firing is more forgiving in placement
At sub frequencies it makes no difference if your sub is front, up, down or side firing - Room modes are room modes and if you have issues that way you will have to contend with them by varying your sub placement, room treatment or both. Going with multiple subs, IMHO, works best "if" you have serious room mode issues.
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Old 1st March 2014, 02:37 AM   #17
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Quote:
Originally Posted by OllBoll View Post
You could do like this:

Use dual drivers instead, smaller if you don't have a need for extreme SPL and build the box around them. Wired out of phase of course.

You will gain vibration cancellation which is awesome for a sub, you will also gain massive even order distortion cancellation which is even better, especially as copper rings doesn't do much in sub drivers down low. PP subs like this are awesome =)
Interesting..only have one driver though.. What is the calc for determining the necessary volume of the cavity and area of the opening? I assume that it would be like a bandpass if too small..
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Old 1st March 2014, 02:41 AM   #18
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Quote:
Originally Posted by Cokewithlime View Post
At sub frequencies it makes no difference if your sub is front, up, down or side firing - Room modes are room modes and if you have issues that way you will have to contend with them by varying your sub placement, room treatment or both. Going with multiple subs, IMHO, works best "if" you have serious room mode issues.
Totally agree that at sub frequencies it makes no difference, but crossovers aren't straight dropoffs and the driver moving isn't always silent. Also, your output, expansion, etc. will vary if firing into the room vs floor, corner, wall, etc..some scenarios making almost a quasi horn (not always a good one either)..
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Old 1st March 2014, 04:52 AM   #19
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Originally Posted by dutchess View Post
some scenarios making almost a quasi horn (not always a good one either)..
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