Box Modification SPL Gains

[mattd0344 2]

I'm not talking about the amp. I'm talking about the sub. My Nightshade's push terminals seem pretty small and it takes a lot of work to fit two sets of 12 gauge in one terminal when connecting in parallel with my D2 sub.

[shizzzon 461]

Get a 4awg to 8awg reducer if necessary. Wire up to 4awg will fit in the insert and the adapter is a standard 8awg fit that would fit in the terminal. Although... never used on speaker terminals for subs, the springs may not be strong enough to hold them in place like a screw can.

[sundownz 197]

I trim it down a bit to fit.

[shizzzon 461]

when should we expect the next test?

I'm unsure which one is next?

45degreee the rest of the box?

resin all the corners now?

rip the 45s out and arc next?

[sundownz 197]

Wait and see

I tore up a sub today @ a MECA show doing drive-by SPL so I'll have to build two new ones for testing.

[sundownz 197]

Woops - I made a mistake earlier... must have looked at the wrong data for the subs I was using before. They are 3.0 DCR and not 3.5 DCR as I was assuming before.

With those D4 coils all in parallel I had 0.375 DCR per amp, which is more like a 0.5 ohm nominal load.

With the D1 Nightshades I built I have an actual 0.50 DCR load per amp, which is more like 0.70 ohms nominal.

Even still... it is doing 154.3 dB with a DCR much higher.

I may have to wire the amps down lower and try it that way with these coils. Or use a different amp configuration like four 1500Ds wired down to 0.25 DCR each to get a better comparison.

[ncacoates 104]

Looken good man. Like the wiring man exactly how i did it and it seems to work like a champ.

[sundownz 197]

So far the 1500s aren't much liking the 0.25 load. I can roll it and get a score but not high enough to do a GOOD score.

So I may just need to wait for 3500s and use the 0.5 DCR load for now and then build some other subs later once I get it all dialed it for the 0.375 DCR load again.

[turn it up 1]

So far the 1500s aren't much liking the 0.25 load. I can roll it and get a score but not high enough to do a GOOD score.

So I may just need to wait for 3500s and use the 0.5 DCR load for now and then build some other subs later once I get it all dialed it for the 0.375 DCR load again.

The amps go into prtect modde when run at .25 is it.

Running four of the 1500's at 1 ohm each.When i seen the .25 got me going cause could run mine at .5 strapped .25 each for burp's if worked

Edited May 23, 2009 by turn it up

[DeeCee 0]

Jacob, just remember when you resin, let it pool. You get a more uniform layer that way that doesn't require much sanding if any.

The process takes a while as you'll have to let the resin set before moving the box to another position for the next wall.

For the bottom, double side some duct tape leaving a around half to stick to something. As long as it prevents the majority of resin from leaking then you're good.

To get the most uniform layer, you need to gently tip the resin side to side, front to back. You'll get the hand of getting level pretty fast.

Not sure what you have for reinforcement inside the box, if any, but look at steel rod to tie top and bottom together if you have top panel flex.

Pooling resin on a box wall.

Using tape going across the base of the bottom wall to prevent leakage off the end and to the sides.

Edited May 24, 2009 by DeeCee

[Derrick824 4]

The amps go into prtect modde when run at .25 is it.

Running four of the 1500's at 1 ohm each.When i seen the .25 got me going cause could run mine at .5 strapped .25 each for burp's if worked

The amps are only having trouble in the Jeep cause Jacob is running 16v. In a 12v setup they burp @ 0.25ohm just fine. I don't like recommending 0.25ohm to anyone though cause they get touchy wired that low. You need to know what you're doing and your gains absolutely must be set correctly. A good electrical is also needed since the current draw goes up substantially when wired low.

[shizzzon 461]

i'm surprised he hasn't blown the onboard fuses yet on those 1500s.

[sundownz 197]

Interestingly... when I was running them at 1/2 ohm each I got up to 2640 watts from one of my 1500s on burps and still never blew the fuses.

[sundownz 197]

I also discovered that the in-vehicle tuning of my box has actually been 37 Hz for the new enclosure...

I cut 4" off the port and got it up to 39 Hz so far *laughs*

Looks like I may have to take off most of the port to get it to where I want it.

[justin smith 0]

damn that thing was tuned low

[sundownz 197]

Indeed. Out of vehicle tuning was around 45 or so. Dropped in the Jeep it went down to 37 Hz.

Another issue... with the port shortened I can't get my PVC pieces back in above the port as the magnet hits them!

So... back to the drawing board for a bit.

[Derrick824 4]

Keep in mind that as you cut down the port you're adding that volume to the box which in turn lowers tuning.

[sundownz 197]

I continued to cut it down - confirming the higher tuning with output current measurements. Interestingly my score went down when I got the tuning higher. So... I am going to re-build the port and even try longer ports to see what happens.

[ncacoates 104]

I continued to cut it down - confirming the higher tuning with output current measurements. Interestingly my score went down when I got the tuning higher. So... I am going to re-build the port and even try longer ports to see what happens.

That's weird jake id think higher tuning would be the ticket. Ever thought about trying aero ports out?

[sundownz 197]

I continued to cut it down - confirming the higher tuning with output current measurements. Interestingly my score went down when I got the tuning higher. So... I am going to re-build the port and even try longer ports to see what happens.

That's weird jake id think higher tuning would be the ticket. Ever thought about trying aero ports out?

It is on my to-do list once I buy some 6" aero-ports for testing.

[ncacoates 104]

I continued to cut it down - confirming the higher tuning with output current measurements. Interestingly my score went down when I got the tuning higher. So... I am going to re-build the port and even try longer ports to see what happens.

That's weird jake id think higher tuning would be the ticket. Ever thought about trying aero ports out?

It is on my to-do list once I buy some 6" aero-ports for testing.

Sounds like a plan. Id be interested to see the results compared to your flared boxes

[banginAltima 0]

We got spare 6" aeros you could use.

[sundownz 197]

More fun stuff...

When I cut it down until it was reading 39 Hz - score was 0.2dB down but I couldn't get my PVC piece back in so it would have either been the same or 0.1-0.2 up.

Cut it down more until it was reading 41 Hz - lost 0.9 dB!

Re-built the port to 4" longer than before... simply taping it up against what was left of the old port and building a quick brace piece to hold the parts together in the center... no glue at all, no smoothing, nothing special.

I am within 0.1 dB of my score before cutting - 154.5 dB.

My iPod only has tracks down to 35 Hz and by the current measurement 35 Hz had the highest current... so the box is at least 2 Hz lower tuned than before and is about the same in SPL - potentially louder once I get the parts properly joined back together.

[ncacoates 104]

that's wired man doesn't make any sense but what do i know lol