Complted GR Sub (Down Firing Design)

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jeff lam

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Complted GR Sub (Down Firing Design)
« on: 24 Nov 2005, 01:20 am »
After a a few months of working on this thing a couple hours a weekend I finally finished.  I wanted to try this thing out as the price is right and the size is great for the performance.  This is my first actual box type sub project so of course there were some hicups and lots of runs to Home Depot and Southern Lumber.  I was just ready to go with a more elegant style sub after having my Tempest based sonosub for 3 years.  I haven't done any critical listening yet but first impressions are very good.  Its the standard 2.4 ft^3 but its a downfiring design with front firing PR and rear mounted amp (Apex Sr.).  I didnt like the side mounted amp look so the only option was to do a downfiring design and I'm happy with the way it looks.  There are some streaks with the poly I may buff down later.  Next time I'll use easy wipe on poly with more coats.  This is where the expertise and tips of Brian, Hank, Al and others come into good use.  Overall the wife likes it, I like it, everyones happy.  Review to come shortly after I get together with a friends to test it out.

Here are a few pics:


More Photos of Construction and Building Process











Also a peek at the Tempest sub










More Photos of Construction and Building Process

IronForge

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Complted GR Sub (Down Firing Design)
« Reply #1 on: 29 Nov 2005, 06:28 pm »
I took a look at your pictures.. looks nice.  Any additional thoughts after listening to it for a week?

What type of wood did you use for the top and the side trim?

kfr01

Complted GR Sub (Down Firing Design)
« Reply #2 on: 29 Nov 2005, 06:34 pm »
Looks good.  How does it compare to the tempest?

Red Dragon Audio

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Complted GR Sub (Down Firing Design)
« Reply #3 on: 29 Nov 2005, 06:45 pm »
Looks good!  Nice job for your first sub project.

How much space is between the down-firing sub and the floor?  Maybe during your test phase, add some blocks to the bottom to raise it up a few inches to see if it affects the sound for better or worse.


Danny Richie

Complted GR Sub (Down Firing Design)
« Reply #4 on: 29 Nov 2005, 07:32 pm »
Looks good but the woofer does look like it is way too close to the floor. It needs to be about 3" off the floor.

jeff lam

  • Jr. Member
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Complted GR Sub (Down Firing Design)
« Reply #5 on: 1 Dec 2005, 03:35 am »
I thought the woofer would be too close to the floor but isnt obstucted at all.  I used the PE large spikes as legs and the driver is recessed with a 3/4" panel.  So thats 2-1/4" from floor to woofer mounting panel.  Danny, what happens if its too close to the floor?  Air bouces back up and causes feedback to woofer?  I may have to add in a spacer between the spike and cabinet.

I used real maple hardwood for the top and side trim.  The top is 3/4 maple glued up panel, the trim I was going to use solid hardwood with miter joints but found this nice corner molding at my local lumber store I thought would be much easier and look great too.  Its already routed with some type of ogee design.

After listening for a week it is loosening up and sounds awesome.  Granted, my tempest did as well.  My tempest design actually wasn't an adire standard design.  This design isn't on the site but was given to me from Dan Wiggins himself.  I wanted a smaller size sub, low tune, and a tight response.  So he gave me this tempest design.  6.1 ft^3, 17.5Hz tune, .577 Q.  He said I would sacrifice output but that was fine with me as the tempest has more than enough.  It hits over 110db easy in my room across all frequencies at tuning point and above.

That being said, comparing the two is tough.  The GR sub doesnt go as low and doesn't pressurize the room quite like the tempest does, but I dont expect it to.  The tempest will naturally move much more air since its a 15" driver with 6.1 ft^3 to work with and I was giving it nearly 500 Watts.  The GR has a musical response unmatched form a sub I've heard yet.  Great tone from a PR design.  I have heard other say their tempest wasn't nearly the SQ the GR is, perhaps they built the EBS or Adire alignment which may have a higher Q...  I will say my tempest sub is a fine sounding sub, neither is leagues above the other in SQ.  I do prefer the tone of the GR for music and movies.  I also love that this is all done in a 2.4 ft^3 box and at this low price.  And as far as comparing my box sub to my tube sub from an asthetics point of view... there is no contest.  1 thing I will miss is showing off my huge, unreal sub that will make you feel nauseous when playing test tones at 17.5 HZ :mrgreen:

PS: why do my pictures keep disappearing?

Danny Richie

Complted GR Sub (Down Firing Design)
« Reply #6 on: 1 Dec 2005, 04:35 am »
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Danny, what happens if its too close to the floor? Air bouces back up and causes feedback to woofer? I may have to add in a spacer between the spike and cabinet.


You will load the driver on the front side. Think of it now as a woofer in a box with a PR firing into a really small ported enclosure.

The pressure loading on the front of the driver will keep it from playing as low and as loud as it could.

You might try putting the spiked feet on a flat and heavy sheet of MDF, maybe even two layers thick and set it on the floor for the woofer to fire into. Then make a set of adjustable legs and try it at various heights. My guess is that about 3" will be a minimum. Optimal might be closer to 4".

Quote
PS: why do my pictures keep disappearing?


I am not sure but it could be the server that you have them uploaded to.