New Sub Box for My Miata

[Bruno240]

Im still working on it but this is what i got done after one day. The next day im off work, im going to cut the hole for the sub and the terminal. Then its getting a coat of black paint. and maybe some laquer. Then its getting carpeted black. and everything is getting hooked up. Ill keep you guys updated. here are the pics so far. Im thinking my box is very big. but that just makes it sound better.

This is going to sit on my rear deck and the speaker will point down. carpet all around and you wont see a thing.

[PoorManQ45]

Bruno: You don't have to use a standard terminal.

I personally have found that just drilling a hole and feeding about 5~10ft of speaker wire(s) through it works great, and it costs less then terminals(read: free).

Any update on progress?

[Silvia2b]

You built that for a miata? Are you planning on putting it the trunk? Every one Installed in the miatas were not heard inside the car, unless it was avented style enclosure and you made a custom vent to the cabin around the gas tank. Or are you going to put it on the package shelf and then remove it when you put the top down.

PMQ is right, terminals aren't a necessacity unless you remove it quite often. The best solution and seal will be a smaller hole the same size as your speaker wire, the use hot glue or silicone (climate dependant). Please be sure to mount the sub enclosure to get the best response from your sub (+3db).

I always appreciate hearing others projects, and trials. Have fun, post back when you have results.

[Bruno240]

it is finished now. but requires some tweaking. I need to get another 3/8ths of an inch off the height to get the top to go down with it in. but thats not a big probelm since top down weather is just about done.

ill get some pics up soon. it looks good tho.

a question tho. when i have the volume up really loud my lights dim and ****. how can i fix this? do i need one of those capacitors? ill have some pics up soon of it in and everything

[PoorManQ45]

a question tho. when i have the volume up really loud my lights dim and ****. how can i fix this? do i need one of those capacitors? ill have some pics up soon of it in and everything

Nope, like most vehicles your alternator is only capable of handling a little more current draw then what would be required when all the stock electronics are on.

The ONLY solution to this is to upgrade the alternator

[Bruno240]

It did take awhile but i got around to taking pictures of the finished product. It still needsa little tweeking. Such as im going to sink the lower board into the box so i gain another 3/8th of an inch so my top will close smoothly. well here are the pics.

[Bruno240]

another

[Silvia2b]

Cool, looks good. Don't forget what I said about mounting it somehow, you'll get added auidable performance (+3db) and safety how much does it weigh? 35-40lbs? Just think if you had to stop suddenly, or god forbid, were in an accident that 35 pounds would become a large projectile.

I like your logic with being able to get the top down, now if you had roll bars it would be easy to figure out a quick way to attach the box to the bars themselves. The gas tank is right beneath that packeage tray (isn't it?) so mounting hardware would have to be carefullly placed to avoid conflict with that infrastructure.

Good luck and cheers.

[PoorManQ45]

Cool, looks good. Don't forget what I said about mounting it somehow, you'll get added auidable performance (+3db)

It wouldn't be that much due to the fact that the enclosure weighs so much.

What you're talking about is a constant reference point. WHat I mean by this is, when the sub is off, that's the reference point. You NEVER want that to change by itself by having th eenclosure moving while the sub pounds. This will decrease efficiency. I'd put it at <1dB though

[Silvia2b]

Yes you will lose audio effeciency, due to the box moving vibrating and turning acoustic energy into mechanical energy. The number is 3db however, same as if you had added an extra wooofer.

[PoorManQ45]

Yes you will lose audio effeciency, due to the box moving vibrating and turning acoustic energy into mechanical energy. The number is 3db however, same as if you had added an extra wooofer.

That might be a good number to tell people sinse it's a very noticable decrease, but unless that box is actually rolling around in there, the loss is going to be less then that. It's like the doubling of power gives you a 3dB increase. It's a good reference point, but not completely accurate. It depends more on the installation.

[Silvia2b]

PMQ - You can tell people what ever you want. I like to tell them the truth not BS. We have tried and RTA'd many different sub boxes when we have down time, according to the audio control real time analyzer in our shop, usually we get about 2.6-3.2 db of increase just from mounting the box(secured with bolts screws other hardware) in most sedans where the trunk is separated from the cabin where the mic. is mounted. This does vary at different frequencies, but overall it is mostly above 2.5 db across the spectrum the sub is able to reproduce.

So when I tell customers that show up with a sub box that is home built or purchased from some internet pawnshop, and it isn't mounted, I'd suggest mounting it. Will I charge them for my labor to do it and prove that it will sound better? You can bet I will. Will I go through the task of setting up the mic and RTA for every sub box that I install in a vehicle, not likely I usually have better things to do with my time. Like hang out here on NICO.

In hatch vehicles, or a Miata package shelf it may slightly less than this number. But overall the sub will have a greater response due to cabin size and proximity to the mic. The only way to have solid proof is to use a RTA before and after and compare the printouts of the same scale.

[PoorManQ45]

Bah, were your tests taken with the vehicle in motion, or sitting still?

If it was moving, then yes your results may have been accurate, but if the vehicle was sitting still then your results are total BS.

Note, i'm from the home audio field where we don't bolt our subs to the floor, we just set them there(even on hard wood). The sheer weight of the enclosure(if built of MDF) holds it in place perfectly well.