Eclipse 8812's ------> Ported?

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Reaper
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Eclipse 8812's ------> Ported?

Postby Reaper » Mon Nov 01, 1999 7:28 pm

I'm getting myself a pair of Eclipse 8812's and I was always under the impression that they needed to be sealed. But I was talking to my local shop and the guy there who, although rare for salesmen, really knows his shit.

I told him I wanted a lot of bass, but I wanted it to be very musical too. He told me that from a purely SQ standpoint you should have them sealed up, but that porting them correctly will crank up the bass response but won't get sloppy because of the solid motor control. Any thoughts? I've heard them sealed with around 800 watts on them and they sounded awesome but what do you think?
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clay
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Postby clay » Mon Nov 01, 1999 8:32 pm

well they do sound great in a sealed enclosure. Yes they can be ported and you will get a bit more level (anywhere from 2-6 db's) Yes with the build quality of the Eclipse's they can stil sound musical and not boomy in a ported enclosure. See if you can hear them in a ported box.
here is some more info for you for Eclipse http://www.freeyellow.com:8080/members7/eclipse-car/
see ya
clay
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JASON
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Postby JASON » Mon Nov 01, 1999 10:03 pm

I heard two of them in a ported box and they pounded. I ordered three f them and I am still waiting for my box. It should be about three more days. I will tell you what I think If you have not decided already. I thik they will be very loud
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jlaine
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Postby jlaine » Thu Nov 04, 1999 1:38 pm

Looking at the mammoth amount of excursion and the design of these subs I would tend to think that they would wail in a ported box, but it also has to be taken into effect that the excursion needs to be controlled, mainly with the restricted airflow of a sealed box or a bandpass enclosure. If you are planning to run these beauties near their capacity of 500 watts RMS you had better be careful, eventual voice-coil destruction is definitely on the horizon because there is nothing to hold this sub back from its own power...
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Postby cyberpunky » Thu Nov 04, 1999 2:00 pm

Although you could run a ported box with these subs, you would also need to run a sub sonic filter set to just below tuned freq of box to have any hope at running that much power without unloading, but considering that you state your prime goal is SQ, then forget about the extra Db as these babys are damn loud in a sealed box, and why risk blowing them for SPL. Remember that anytime spent listening to sound over 120 Db will permanently damage your hearing, and listening to the best system, half deaf, is probably not why your building it Image.
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ShadowStar
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Postby ShadowStar » Thu Nov 04, 1999 5:58 pm

Well... I would say that 500 watts (of unclipped power) is a VERY safe level for these subs- The ported box issue- Go for it, bearing in mind that the woofer WILL destroy itself underneath the tuning frequency, and damn quick too- It has one of the strongest subwoofer motors (in terms of Bl) at 23 tesla-meters, of any speaker availible.

Well- Good luck.. And if you end up with a good ported box, tell me how it sounds- I have wanted to port mine (due to the inefficiency) for a long time.

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Postby Phloodpants » Mon Nov 08, 1999 3:00 am

Hey Shadowstar, we had this dicussion over at Elite Car Audio, and I think you may find it interesting, so I'm cutting and pasting it here...
I have known the designer of the Eclipse 8800's for years now, and he has always designed his drivers with a ported design as the primary configuration.

...but...

It's a hell of a box you need to build.
It needs to be tuned to 20Hz. Then you need a subsonic filter at 20Hz to prevent the driver from overexcursion, because the driver will act like it's running free-air below 20Hz. So you gotta have a subsonic filter. Then, to get perfectly flat response down to 20Hz, you should have a slight bass boost of 3db centered at 20Hz. No biggie if you can't provide this. It's only 3db, and the car response will make up for it anyways, but I like it best this way.

There is a perfect amp to do just this: The Infinity Beta300. It puts out a clean 1000W into 4 ohms, and has a subsonic filter as well as a variable center bass boost that you can set to 20Hz with 3db of gain. Crutchfield has them on special for $500. I have one, and absolutely LOVE IT!

In a sealed box, you would want more than 500W to each 8812, but with a ported enclosure, this is more than enough juice to drive them to the max.

My box is 1.6cuFt for each driver, with a 4" wide (and get this) 55" long with two 90 degree elbow joints! The elbow joints are about 9" long physically, but are acoustically about 15" worth. If you can get a little more length than this, it can't hurt. That's what it takes to tune a box that low. Don't worry about flaring the ports. The air velocity is pretty low with ports that wide.

Anyways, this configuration will give you maximum efficiency and output, as well as being the best sounding configuration. No compromise here with sealed vs. ported.

Good luck, and let me know what you are going to do. I think you'd find the results are well worth it.


HEY Phloodpants...No SQ will be sacrificed with the type of ported box you described???How is that possible?

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Phloodpants
Member posted 11-01-1999 11:08 PM
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Absolutely not!
It's a common misconception that ported enclosures are ALWAYS a compromise. The thought is that as you gain efficiency, you lose SQ. This is too simplistic to be true. It may apply as a general rule though and here's why...

Most ported boxes are tuned to somewhere around 35Hz or higher. That means a steep rolloff below that frequency, resulting in less low-bass extension. They are tuned like this to avoid overstressing the driver at low frequencies. In a ported enclosure, the driver acts as though it is in no enclosure at all below the resonant frequency of the box. The standard approach is to tune the box fairly high, which causes a steep rolloff before it gets to the very lowest frequencies, thus preventing overexcursion.

To get really deep bass from a ported enclosure, you need to tune the box really low, like 20Hz. The problem with this is that you are going to have really bad power handling below the resonance of the box, in this case 20Hz. Lower frequencies require more excursion, so we are talking about SERIOUS OVEREXCURSION HERE!!

This is easily fixed with a subsonic filter. Voila! No overexcursion, and you have a system that goes clear down to 20Hz.

Another stereotype about ported enclosures is that they're "boomy". This comes from the relatively high tuning frequency of most designs, and is the major complaint about the sound quality with ported enclosures. By tuning the box to 20 Hz, you create a system with no hump in frequency response and better control due to the higher electrical and physical damping at these lower frequencies.

Not all drivers are suited for this application. You definitely need a high-excursion driver with like the Eclipse or the GZ's to get outstanding results.
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Postby Lambch0p » Mon Nov 08, 1999 3:47 am

I'm thinking of porting my exact 12's... Soon I think i will be replacing my current amp with a D300HC.

Right now they are 1.31 cubes each sealed, could i assume the similar results if i ported? Obviously not with the EXACT (no pun intended) specs, but if I went about porting in the same manner...Or would 600-700 watts to each sub in a ported box be way too much power?
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Reaper
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Postby Reaper » Mon Nov 08, 1999 3:42 pm

I'm going for it! My local shop is hooking me up with a 2 chamber 4f^3 box with specs straight from Eclipse. Not sure what the tuning frequency is going to be but my amp has a subsonic filter at 25hz so I should be cool.

I'm psyched because I just heard them ported and they were so amazingly accurate and tight I couldn't believe it was a ported box. And when we cranked it man I though my brain was gonna pour out my ears. I'm gonna have about 400-450 rms to each sub. I am so psyched!

Any more thoughts?
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ShadowStar
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Postby ShadowStar » Mon Nov 08, 1999 5:55 pm

Phlood- I'm on elite, just haven't been over there for a while...

Thanks for the info, I've already experimented with some ported boxes.. The insane port lengths dissuaded me from pulling through with the design, and also the fact that my 5v deck and older power series amps would destroy my 8812.6's in that application.. I'm working out the problems now.

ShadowStar

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