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TimVG

Build thread: Ported subwoofer

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My second build thread! For my secondary system, I have opted for a ported subwoofer. There is room for one subwoofer only here, and due to the leaky nature of the room a ported variant simply works better in my experience. 

The driver I have chosen is the Sundown X-15 model. It has not yet been tested here on data-bass, but the specs look solid and other models that have been tested were received generally positive. 

The box will be slightly over 5ft³ (150l) + port volume and built completely out of leftover MDF I still had around. A big slot port will be utilized to counter noise and compression, the tuning frequency should come out around 16hz. 

The only tools I'm using will be a jigsaw and a sander. No CNC cut materials this time.

Anway, some progress pics.

xgkshc.jpg

cox03.jpg

2sadwys.jpg


fxgj9z.jpg

 

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Looking good.  And beastly next to that little bookshelf speaker!  :)

Thanks! Yeah, I may have gone overkill on this one. Sounds great though. 

Tuning ended up at ~14hz due to the stuffing materials used, and overall efficiency went down. It is however still a very capable sub and this driver can move A LOT of air.

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Thanks! Yeah, I may have gone overkill on this one. Sounds great though.

Tuning ended up at ~14hz due to the stuffing materials used, and overall efficiency went down. It is however still a very capable sub and this driver can move A LOT of air.

Doesn't seem like overkill to me, looks like a sub done right! It does look like it can move some air, that's one nice looking driver ... that surround looks like something you would tow behind a boat!

 

Any measurements you can share?

 

Thanks

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Thanks man! Measurements coming somewhere next week after the livingroom (where this setup will be located) has been refinished. I took some earlier but did not save them, It digs all the way to around 13hz and does so with authority. My little bookshelfs obviously can't keep up at all. I had two captivators in this room (Sold them when I got to a dedicated room as main setup) and it reminds me of them, although with more extension.  

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some quick measurement and 10 min of playing with levels and EQ gives me this. Sounds good. I like this sub.Don't mind the high frequency dropoff, the mic wasn't setup right for full range.

ka49p2.jpg

 

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some quick measurement and 10 min of playing with levels and EQ gives me this. Sounds good. I like this sub.Don't mind the high frequency dropoff, the mic wasn't setup right for full range.

 

ka49p2.jpg

 

 

 

From 15-60Hz that is terrific.  Now you need another one to smooth out that response....

 

JSS

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Unfortunately this room has exactly one location where I can fit a sub, but it does sound good actually! My two little bookshelves run out of steam way before this thing does. It's almost a shame I'm 'only' using this one for music and TV shows (and the occasional movie), I could have very well gotten away with a sealed enclosure.

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80hz. The dip in that region however is caused by floor/ceiling cancellation. Unfortunately it's the only place I can put a subwoofer in this room.

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The floor-to-ceiling dip looks all too familiar. I wonder what would happen to that dip if you flipped the sub upside down?

 

That driver looks swell. Any more info on it (cost, availability, T/S, Xmax*2*Sd, etc.)?

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"I wonder what would happen to that dip if you flipped the sub upside down?"

 

Spot on.

Just as placement at the floor boundary, maximally couples and excites resonances in the vertical axis. Conversely, employing null mode placement by locating the driver up off the floor (and close to a vertical null), theoretically doesn't excite that resonance like boundary coupling does. 

 

There's so many complex interactions, you never really know how the FR will be impacted until you try. It certainly warrants some experimentation. I like OmniMic for applications like this ... ie, real-time observation/identification of FR boundary interactions and EQ'ing. Handholding the mic while the test signal plays, can quickly determine the troublesome room axis.  

 

Also, another aspect to thing of is oftentimes narrow dips in response, fortunately aren't that audible.   

 

 

Good luck

 

An acoustic axiom;

Resonant frequency and distribution of room modes is determined by the room's dimensions.

The degree of excitation depends on the position of the source.

The degree of audibility depends on the position of the listener.

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The floor-to-ceiling dip looks all too familiar. I wonder what would happen to that dip if you flipped the sub upside down?

 

That driver looks swell. Any more info on it (cost, availability, T/S, Xmax*2*Sd, etc.)?

I wanted to experiment with that, but it's not gonna pass WAF with that big 15" driver in mid air I'm afraid  :) 

 

T/S parameters can be found here. http://www.sundownaudio.com/misc/2013_Woofers%28X_Zv4%29/X-Series-Specs/X-15%20D2.jpg

Xmax is an honest 30mm, Xmech is around 50mm, so damaging this driver in 'normal' use is nearly impossible. Price is around $430

 

I chose this driver because it is also readily available in Europe (where I live), and heavy duty subwoofer drivers are very rare over here.

 

It was originally developed for car audio use, but it seems to have good parameters for use in a home environment as well.

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If you can test it upside down one Saturday afternoon while the missus is at the shops ;) you can see if it makes a difference.  If it does, and for the better, you could always put a full-length front grill on from that audio-transparent mesh/cloth material :)

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Haha...I have the 18" Zv4 in my garage with the same surround. Good luck making a grill to clear that thing at full extension! It'll need like 4" of clearance or something crazy. It already protrudes about 2" from the drover frame!

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I think you'll like that driver. And yes, a grill is not an option on this cabinet. You could but you'd have to recess the driver for a couple of inches.
If you're going with sundown, I still think in terms of home use, the X series would be the way to go for most people. 
Although I believe they do custom work as well, so if you really wanted a driver for home use with an insane (40mm) amount of clean throw, I guess you could order one.

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