MrSkippyJ

use the DD-1 to get everything set to max clean output (source -> everything in between -> amp) then use a DMM to set the output of the amp to whatever you need. There is a formula for determining the output of voltage needed for however many watts you want. It's not perfect but it should be close enough to be safe.

Why is the gain setting changing just because you are wiring the voice coils differently? Did you have it set to something lower than max clean output with your sub wired to 4ohms?

Ground gauge should be equal to positive side gauge. No need for a grounding block but you certainly use on if you want too. 4g speaker wires??? No. 12g is by far big enough for that amp. The grounds for the battery and alt/engine are so short that you can probably get away with 2 or 4 gauge. Especially if you are running a factory alt. But my own personal OCD wouldn't let me use 1/0 for power and a different gauge for negative.

regular halogen headlights? they dont have any kind of voltage regulation so any changes in voltage will dim/brighten them. Even a high output alt will lag behind current demands. So it is perfectly normal to see diming even with a HO alt. You can either just ignore it or get some voltage regulated lights.

What are your plans for amps to run all these speakers? You have a 4 channel, are you adding another 4 channel or what?

I wouldn't even bother with it on music. It's going to be all over the place.

What headunit are you using? What kind of bass knob are you using? Use a spare RCA cable with one end stripped and a DMM set to AC volts to check output from the headunit. Just be sure not to short that wire out. Use some test tones at 0db to check output. Make sure you aren't filtering anything out or boosting anything. IE don't test your sub output with a 1k hz test tone, etc... My guess is you are leaving output on the table from your headunit. How did you set your headunit up? You can use a DSP if you want too, but unless you are in the gutter with output voltage from your headunit you won't need it for a voltage boost. Personally I like a minimum of 2V output, but anything about 1V or so and you will be fine.

Mind shedding some light on this? How did you come to that conclusion?

what little it was, you are welcome!

So I can't say much for box specs and how well they will work, someone else can help there. I think the overall design is fine, however I am not sure about port/sub direction being optimal. You might have better luck with port forward or up rather than to the side. I think a 2" dowel is pretty massive overkill for this. I bet you could get away with a 1" dowel and just not worry about how much volume it takes up, it won't be enough to make any audible difference. I used that calculator you provided for the port length and used these measurements (I rounded everything to the tenths): box (internal) 34*13.15*13.5 = 3.6 port (internal) 13.5*22.6*3 = .5 (I used 33hz like you did from above) net internal with sub and port removed = 2.9 Hopefully someone can come along and let you know what configuration would be best and if those specs would work for your equipment. I do enjoy my RG a ton, especially on long trips but my Heritage is the one I did all the motor work too. It is far more "fun" to ride.

I can't recreate your numbers with the provided measurements. Could be it's just early and I am being dumb. The external depth of 15.25", internal depth of 13.5", 15" from front of baffle to inside of backwall doesn't work. That leaves .25" for your back wall. I'm guessing your actual external depth is 15.75? Also I can't figure out your port calculation either. You didn't list the port height, but I am guessing internally it would be 13.5 based on the 15" height. That wouldn't be .8 that would be closer to .5. Not sure about the brace at all. Where is the 32" coming from? I'm not sure a 2x2 would be ideal in the middle of a port either, but I don't know much about that so someone else can help you there.

Nothing wrong with JL listing actual specs instead of under rating them (or over building stuff). I’ll never understand the JL hate. They make some incredible stuff that is pretty unique and happens to sound incredible as well. Nothing wrong with sundown, dc, b2, etc… either. Save the hate for companies that make a 100watt amp and sell it as a 2000watt amp. I’d much rather have JL type companies that provides accurate specs or Sundown types that under rate (or over build) stuff.

They have some: https://soundsgoodstereo.com

does it sound better or worse when you are only playing one sub at a time?

I would ground them individually if it was me. I would also run another run from alt to battery as well. If you are doubling up all your grounds it probably makes sense to double up the + as well.