posted
I am going to start putting corner pieces in my box as well as adding resin. I will be tracking my gains from these things here.
I will do each corner with a 45 degree piece first (ripped 4x4 lumber). I will also try pieces that are cut into an arc (same 4x4 but with an arc cut) to see which is louder.
This will be done one corner at a time.
This may take a while but I am going to start today.
Some initial results soon.
Base-Line score from the end of my dampener log :
155.2 dB @ 48 Hz
-------------------- - Jacob Fuller Posts: 990 | From: Mooresville, NC | Registered: Oct 2001
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posted
First piece in place - screwed in with tape along the top as that edge was rough:
This resulted in a GAIN :
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I tested 49 Hz as well to make sure my frequency did not change - I metered 155.2 dB @ 49 Hz. I also gained 0.1 dB here compared to before but it is still not as loud as 48 Hz.
-------------------- - Jacob Fuller Posts: 990 | From: Mooresville, NC | Registered: Oct 2001
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posted
While I'm in the area I tried something random - metal taping all around the plastic trim piece at the bottom. I didn't have enough time remaining today to take the whole box out and do another 45 piece so I wanted to try something
No change... but at least my 155.3 is consistant :
There was alot of odd noise on the meter this time, though... not sure why, maybe a fluke.
-------------------- - Jacob Fuller Posts: 990 | From: Mooresville, NC | Registered: Oct 2001
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posted
this thread is a good one! I would like to make a suggestion for your testing.....considering that the angle you installed in the box was a gain, perhaps you should try removing it and addind a layer of mdf to the inside wall over the vent to take away the equivalent volume.
sometimes but not always, an angle is a gain only because your removing internal volume. It might not be the case for your build but worth a try anyhow to see!
posted
Just keep in mind that adding corners is also shrinking box a little. And I'm still impressed that you're that loud with a slot port. When you going to start working with a flared or aeroport? Break 157 probably pretty easy.
Posts: 1770 | From: elgin | Registered: Jan 2003
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posted
try usen a pics of pvc in sted of that wood and take a 4in grinder and make sharp edges on each side of the then 400 grit the sanded parts take that wood angel out let me know how this works.
You can rip it on the table saw i bet you will gain a lil more over the wood.
-------------------- TEAM XTREME LOUD AUDIO THE LOUD CROWD Team Dc Sound Labs. Posts: 2789 | From: Springfield Ma | Registered: Apr 2004
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quote:Originally posted by canadian no-wall: this thread is a good one! I would like to make a suggestion for your testing.....considering that the angle you installed in the box was a gain, perhaps you should try removing it and addind a layer of mdf to the inside wall over the vent to take away the equivalent volume.
sometimes but not always, an angle is a gain only because your removing internal volume. It might not be the case for your build but worth a try anyhow to see!
good luck, i wanna see more progress!!!!
bam!
quote:Originally posted by dtbrown: Just keep in mind that adding corners is also shrinking box a little. And I'm still impressed that you're that loud with a slot port. When you going to start working with a flared or aeroport? Break 157 probably pretty easy.
bam! again.
all corners and angles do is take out the volume out of the box, and fine tune your port (if u put it in or outside the port).
if you start putting corners in the box and gain even more, you need to try a smaller box.
what would produce a good gain in your box is what i call a "wave breaker". put a loading wall between the subs on the inside of the box.
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2006 Street A - 152.7 Certified 2007 Street C - 154.8 Certified 2007 Street A - 154.4 Certified 2008 Street C - 156.3 Certified 2008 Street B - 156.6 Certified
TEAM FEAR OF BASS Posts: 3611 | From: Toronto, On, Canada | Registered: Feb 2001
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I have a smaller version of this box that is not as loud as this box even being tuned to the correct 53 Hz frequency - so I don't want to go TOO much smaller.
The box I have now is almost exactly double the single sub box I have that has worked so well for me - in both volume and port area. It seems to be doing much better than the smaller version so far.
I do have a brace in the center of this box between the subs that currently has a hole in it to allow air flow - I could try covering the hole over and test the "wave breaker" idea later on.
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Old/School,
Once I test all the 45 degree pieces I will be testing "arced" 4x4 pieces as well - like this :
Look carefully and you can see it is a smooth arc. I can use resin and slightly angle the box while the resin dries and make a nearly perfect transition into the piece of wood (I did this in the smaller dual woofer box).
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Jeff,
Once I stop getting louder I'll try some other forms of port arrangement
This arrangement has worked GREAT for me so far and I have yet to find the limit of it so I'm going to keep pushing it until I do!
I can still add more power as well - soon I'll have two 3500Ds... and then once I get it dialed in to the right frequency - four 3500Ds.
-------------------- - Jacob Fuller Posts: 990 | From: Mooresville, NC | Registered: Oct 2001
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posted
I wanted to see how much my internal port PVC piece was doing so I took it out this morning :
* With
* Without
Without - 154.9 dB (verified two runs 12 minutes apart)
With - 155.2 dB
So that piece is worth around 0.3 dB!
The score "with" is within tolerance since my speaker wires moved around in the port with the subs in and out... I need to get those out of the port - will probably do that today before further testing to eliminate that variable.
-------------------- - Jacob Fuller Posts: 990 | From: Mooresville, NC | Registered: Oct 2001
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posted
try flairing the outter port like this see what happens. but do it pice by pice. start small and work your way bigger till no more gain then glass it i used pvc to start it.
the start of the slot i built for my exp
this was the final box and each corner i did with resin and pvc works great ya can start big cut smaller if needed and pvc is smoth like resin and just as dence and the air like to flow over it beter then just wood.
but ya box is looking good pics lets see them.
-------------------- TEAM XTREME LOUD AUDIO THE LOUD CROWD Team Dc Sound Labs. Posts: 2789 | From: Springfield Ma | Registered: Apr 2004
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-------------------- TEAM XTREME LOUD AUDIO THE LOUD CROWD Team Dc Sound Labs. Posts: 2789 | From: Springfield Ma | Registered: Apr 2004
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posted
Just keep in mind that power is great and all but for non wall type enclosures like you're doing 75% of your potential spl is from the enclosure.
Port design will be your big gainer no doubt. If you've used a smaller box what port did you go with? I'd assume smaller then your current port or at least longer then your current port cuz with the smaller box you'd need to load it more by either smaller or longer port or combo of the two.
Either way you're doing well.
Posts: 1770 | From: elgin | Registered: Jan 2003
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Port was a bit smaller on the smaller box - 156 in^2 vs. 195 in^2 for this box. The new box has almost exactly double the volume and port area of my very successful single sub box (154.3 dB with one Nightshade 15 in that box / Four 1500Ds).
With my previous small dual sub box I only gained 0.9 dB going from two 3000D to four 3000Ds.
With the single sub I gained around 2 dB doubling the amps. With this box I will try to find out if the lack of "linear" gains in the other box was from battery power, box size, or maybe something else.
If all else fails I'll try a few things with enclosure :
1) Aero ports (the dark side!!! *laughs*)
2) Another sub / port alignment -- with the single box I do almost exactly the same number with woofer forward and port up and the box pushed all the way against the hatch. This may be a benefit with the dual box but I have not tested it yet.
3) I can also try a forward firing arrangement - I can fit more batteries this way too if I find batteries are a limitation. Scottie suggests I have more batteries so that could very well be the case.
Lots more to try out I'll continue to log everything I try out. I am going to keep pushing this alignment until it quits gaining since it has done so well for me so far.
-------------------- - Jacob Fuller Posts: 990 | From: Mooresville, NC | Registered: Oct 2001
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posted
Yesterday I put in another 45 degree piece:
Nothing really changed - did 155.2 dB.
Then I drilled holes to get the speaker wires out of the port... no change. BUT they were not sealed up - just holes.
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TODAY I got threaded brass rod, washers, and nuts to make a proper connection :
I should add that before I had a smaller wire jumping from one coil to the other to parallel the coils. Now I have two sets of wires going to the common point (this is probably part of the gain I saw).
So I am up 0.3 dB from my best score and 0.4 from the score I was doing yesterday consistently.
I would say part is due to moving the wires out of the port (this has always gained me in the past) and part was due to the superior connection of running two sets of large wires off the coil.
-------------------- - Jacob Fuller Posts: 990 | From: Mooresville, NC | Registered: Oct 2001
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