PDA

View Full Version : Eclipse 87101.4 10" Ported box check my numbers



MellowYellow
02-03-2013, 09:36 AM
I have a Eclipse 87101.4 10" SVC Sub that I would like to build a ported box for. I've always ran sealed boxes because they are simple. I have some MDF and 3" pvc laying around left over from a repair project so why not.

The issue im having is a lack of info about this particular sub. I no longer have the manual (if i ever kept it) and i can only find 1 sales brochure online about this sub. It only listed a few t/s specs. This sub is marketed as "For small sealed enclosures". I used to have it in the WinISD spec'd 0.587ft3 sealed box with 200w and was never pleased with the sound. It was very.. peaky? it would kill 60-100hz but like the graph shows it would drop off sharply below that. Using a real music example the opening bass line in U2's With or Without you would take your breath away.

This will be going into the cargo area of my wife's Nitro, and powered by the bridged rear channels of a PPI 900.4 that is rated at 450x1 @ 4ohms, at 14.4v. 300x1@4ohms at 12v. The sub is rated for 300wrms. My wife will listen to just about anything, so im looking for something that will be well rounded, not suited for any one type of music.

I tried to plot up a ported box in WinISD and I came up with 1.132cu net @28hz. 3" vent 18.85" To my unknowing eyes the graph looks very flat from tuning right up. This looks to me like a very good fit. No peaks and nice flat should make it easy blend into the rest of the sound stage. Also because it's flat i think it should be fairly musical.

So after all that, here are the questions. If someone more experienced in box designing could take a look for me i'd appreciate it.

1, Am I actually barking up the right tree? or am i out to lunch?

2, Sub and port location. The box will be behind the rear seats. Im thinking down firing sub and rear port?. Down fire to protect the sub more then anything and rear firing off the hatch. How you you do it and why?

3, I understand that i have to add the port volume to the box volume but what should I allow for sub displacement? This is only a 10" but it was fairly beefy for it's day. 0.05cu?

4, Any questions that im obviously missing?

These are the T/S specs that I have found

Fs 30hz
Qts 0.44
DCR 4ohm
VAS 0.85 cuft
Xmax (One way) 0.73" (19mm)

Thats it.

Thanks for reading my wall of txt.

ThatChevyGuy
02-03-2013, 10:55 AM
If its recommended for sealed, i would stuff your already existing sealed box with polyfill to bring out the lows. Also a 3" pvc port is not the ideal thing to use...

MellowYellow
02-03-2013, 11:41 AM
I don't have a current box for this sub. Last time it was installed was a couple of years ago.

Why got for ported when it's recommended for small sealed? Because it seems to plot a much flatter graph when ported as apposed to sealed. Like i said, I've never had a ported and im basically just looking to build this as an exercise.

Previously with this sub i've tried 0.587, 0.65, 0.75, 0.85 all sealed, with and without polyfill in each. Im a bit of a tinkerer. The sound from all of those boxes were similar and in each case the polyfill helped with the low end. I was never totally pleased with the sound. It always lacked in the lower ranges and then became overwhelming higher up 60-80hz. This was in the trunk of a gbody Regal, so that may also be a function of the cabin gain.

3" pvc might not be great for ports, but I have some. I can also get some 4" if need be.

This box is only a start. A proof of concept if you will since i've never build a ported box. I figure im probably going to have to build 2 or 3 variants before im pleased. Im looking to learn through the experience and then maybe sometime doing a custom fiberglass enclosure on one side to retain as much trunk space as possible.

ciaonzo
02-03-2013, 11:48 AM
It won't be the end of the world if go with a vented alignment, the Q seems okay for it. Spider my not be designed for a vented enclosure, though.

I suspect it's the driver you're not liking rather than the enclosure.

MellowYellow
02-03-2013, 02:43 PM
I suspect it's the driver you're not liking rather than the enclosure.

Thats quite a possibility. Good thing it's not going in my vehicle.