I have the feeling this wont work but I thought Ide ask.
Ok so here is my question. I have (2) 12” Eclipse model #87121.4 Specs are as follows:
RMS/Peak: 300W/600W
Fs: 20Hz
Qts: 0.40
DCR: 4.0 ohm
Vas: 2.4cuft
Xmax: 0.73
And I also have (1) Alumapro Alchemy 12” With these specs:
RMS/Peak: 300W/600W
Fs: 22Hz
Qts: 0.39
DCR: 4.0 ohm
Vas: 3.8cuft
Xmax: 12mm
My plan is to place these subs In a tri sub box with 3 sealed chambers since, both Eclipses and the Alumapro require small sealed enclosures. They would be run by a Hifonics XI Cyclops, which is a class D mono amp and puts out:
1000watts x 1 @ 1 Ohms
700watts x 1 @ 2 Ohms
350watts x 1 @ 4 Ohms
The reason I have these subs is because I got deals on them. I would rather run 3 Alumapros and make things simple but I cant afford them at their regular price. My question is can I make this work or will I have to settle with running just 2 eclipses and feeding them 700W at 2ohm and would the eclipses take 350w a piece? If I ran all three that would be a 1.33 ohm load and should give them a little less than 300w a piece.
Replies (7)
compvr15s on 10/20/2003 02:55:49
i have seen systems with different brands of subs, and they seemed to be fine, the specs seem to be pretty close on the subs and since they will each have their own enclosure, i dont see that being a problem. i dunno about the wiring though, if the voice coils have to be the same to work or not, wait for swez on this one. good luck, he usually responds quickly
Swez on 10/20/2003 10:36:59
Both subs are very good products for SPL and SQ. They have similar performance data with the exception of Vas. The smaller the Vas #, the stiffer the woofer and works well in smaller enclosures. When using larger Vas subs, a larger enclosure works better as the cone is less stiff.
If you do this tri-sub box with these drivers, make sure you use divider panels between each sub chamber. Not sure on the recommended sealed enclosure size on these subs. If you have enclosure data to both subs, please advise...can give you some additional suggestions.
My first blush at this...
Eclipse: 1.0 - 1.2 cf/chamber
Alumapro: a tad larger chamber here... 1.2 -1.5 cf/this chamber
40-50% fiber fill per chamber
NOTE: These are internal dimnsions
Swez
Relax_The_Mind on 10/20/2003 13:46:14
What are the internal dimensions of the chambers on the tribox in cubic feet? Nice subs by the way. Excellent SQ/SPL as swez said.
Invert the Alumpro and that may help a tad on the difference on the dimensions if the Tri box has identical sized chambers. While still going with the addition of fiber fill.
IMO the medium dense (yellow), or similar, fiberglass insulation from your local hardware shop (or your attic) works better than the stuff they sell at audio shops. It is also a lot easier to install. A lot of higher end home and studio speakers use it. Smooths out the harsh bass hits tremednously...
Some of you should give it a try and maybe we can find the magic ratio.
RTM
Swez on 10/20/2003 18:37:49
Yes, I have used fiberglass before they made polyfill. One that seems to work out nice, w/o the "itch factor" is a new product from Dow Corning home products. It does not itch as I used it in my attic and gave the rest to my brother for his sub designs. He liked it much better than normal fiberglass too. He builds 15-25 boxes a year, so he should know a good product when he finds one.
Swez
Relax_The_Mind on 10/20/2003 19:55:42
Ill try it out swez... too bad for the bare now 'non-insulated' wall in the storage closet in the garage. I dont know exactly what is in my attic but it is not itchy either but its the kind they spray with a huge tube. Looks like shredded insulation sprayed all over the place...talk about being HOT!!! while runnign cables...
RTM
triumph1902 on 10/21/2003 00:19:08
I don’t have the box yet. Just the subs and amp. Inverting the Alumapro crossed my mind also and was probably going to be my next question. As for the recommended enclosure volume for these subs, I have some paperwork with the Alumapro, which states min volume to be .65cft and max 1cft. 88cft being optimal. I figure this to be the air volume with the sub in the box otherwise it seems a little small. As for the Eclipses I believe their recommended box volume was just .75cft. Now as far as the box I can get one of ebay made out of 3/4mdf with 3 separate chamber .88cft each. This box (at 38” long) is a perfect fit in my trunk. So inverting the Alumapro should give it more volume and might actually work.
Now I understand the purpose of the fiber fill to actually make a smaller sealed box act like its bigger. But I really don’t understand the physics of it. If the air in a sealed box acts like a spring which keeps the cones movement regulated, the added fiber material would just replace air which is able to compress. The only way I can think off the fiber material adding to the compression/decompression effect is if the movement of the air between the fibers acts as a secondary spring “mechanism”. Not sure if that makes any sense whatsoever but I have always been curious how that stuff worked.
Swez on 10/21/2003 09:09:22
Yep, you have the right idea on fiberfill... it slows the rear cone wave reflections as it permeates the fibers. This in turn, makes the sub behave as if in a larger box... but the internal volume increase is very small. The main reason I use fill, is to absorb some of the bass energy off the back cone for smoother bass response as there is less bass waver radiation, back to the cone to cause distortions.
Good research on the recommended sealed volumes. Seems to me, a sealed 0.88 cf/ chamber will do fine for both subs. No need to invert the Pro sub if you don't wish to. Just gives more opportunity to damage the sub with that much exposed. Would only gain ~0.67 cf of air space as this is the air displacement of a typical 12" sub.
From what you have stated so far, think this will work out fine.... 0.88cf/sub. If you get sloppy bass from the Eclipse speakers, can always add a few blocks of 2x4's to bring the internal chamber volume down.
Swez
Ok so here is my question. I have (2) 12” Eclipse model #87121.4 Specs are as follows:
RMS/Peak: 300W/600W
Fs: 20Hz
Qts: 0.40
DCR: 4.0 ohm
Vas: 2.4cuft
Xmax: 0.73
And I also have (1) Alumapro Alchemy 12” With these specs:
RMS/Peak: 300W/600W
Fs: 22Hz
Qts: 0.39
DCR: 4.0 ohm
Vas: 3.8cuft
Xmax: 12mm
My plan is to place these subs In a tri sub box with 3 sealed chambers since, both Eclipses and the Alumapro require small sealed enclosures. They would be run by a Hifonics XI Cyclops, which is a class D mono amp and puts out:
1000watts x 1 @ 1 Ohms
700watts x 1 @ 2 Ohms
350watts x 1 @ 4 Ohms
The reason I have these subs is because I got deals on them. I would rather run 3 Alumapros and make things simple but I cant afford them at their regular price. My question is can I make this work or will I have to settle with running just 2 eclipses and feeding them 700W at 2ohm and would the eclipses take 350w a piece? If I ran all three that would be a 1.33 ohm load and should give them a little less than 300w a piece.
Replies (7)
compvr15s on 10/20/2003 02:55:49
i have seen systems with different brands of subs, and they seemed to be fine, the specs seem to be pretty close on the subs and since they will each have their own enclosure, i dont see that being a problem. i dunno about the wiring though, if the voice coils have to be the same to work or not, wait for swez on this one. good luck, he usually responds quickly
Swez on 10/20/2003 10:36:59
Both subs are very good products for SPL and SQ. They have similar performance data with the exception of Vas. The smaller the Vas #, the stiffer the woofer and works well in smaller enclosures. When using larger Vas subs, a larger enclosure works better as the cone is less stiff.
If you do this tri-sub box with these drivers, make sure you use divider panels between each sub chamber. Not sure on the recommended sealed enclosure size on these subs. If you have enclosure data to both subs, please advise...can give you some additional suggestions.
My first blush at this...
Eclipse: 1.0 - 1.2 cf/chamber
Alumapro: a tad larger chamber here... 1.2 -1.5 cf/this chamber
40-50% fiber fill per chamber
NOTE: These are internal dimnsions
Swez
Relax_The_Mind on 10/20/2003 13:46:14
What are the internal dimensions of the chambers on the tribox in cubic feet? Nice subs by the way. Excellent SQ/SPL as swez said.
Invert the Alumpro and that may help a tad on the difference on the dimensions if the Tri box has identical sized chambers. While still going with the addition of fiber fill.
IMO the medium dense (yellow), or similar, fiberglass insulation from your local hardware shop (or your attic) works better than the stuff they sell at audio shops. It is also a lot easier to install. A lot of higher end home and studio speakers use it. Smooths out the harsh bass hits tremednously...
Some of you should give it a try and maybe we can find the magic ratio.
RTM
Swez on 10/20/2003 18:37:49
Yes, I have used fiberglass before they made polyfill. One that seems to work out nice, w/o the "itch factor" is a new product from Dow Corning home products. It does not itch as I used it in my attic and gave the rest to my brother for his sub designs. He liked it much better than normal fiberglass too. He builds 15-25 boxes a year, so he should know a good product when he finds one.
Swez
Relax_The_Mind on 10/20/2003 19:55:42
Ill try it out swez... too bad for the bare now 'non-insulated' wall in the storage closet in the garage. I dont know exactly what is in my attic but it is not itchy either but its the kind they spray with a huge tube. Looks like shredded insulation sprayed all over the place...talk about being HOT!!! while runnign cables...
RTM
triumph1902 on 10/21/2003 00:19:08
I don’t have the box yet. Just the subs and amp. Inverting the Alumapro crossed my mind also and was probably going to be my next question. As for the recommended enclosure volume for these subs, I have some paperwork with the Alumapro, which states min volume to be .65cft and max 1cft. 88cft being optimal. I figure this to be the air volume with the sub in the box otherwise it seems a little small. As for the Eclipses I believe their recommended box volume was just .75cft. Now as far as the box I can get one of ebay made out of 3/4mdf with 3 separate chamber .88cft each. This box (at 38” long) is a perfect fit in my trunk. So inverting the Alumapro should give it more volume and might actually work.
Now I understand the purpose of the fiber fill to actually make a smaller sealed box act like its bigger. But I really don’t understand the physics of it. If the air in a sealed box acts like a spring which keeps the cones movement regulated, the added fiber material would just replace air which is able to compress. The only way I can think off the fiber material adding to the compression/decompression effect is if the movement of the air between the fibers acts as a secondary spring “mechanism”. Not sure if that makes any sense whatsoever but I have always been curious how that stuff worked.
Swez on 10/21/2003 09:09:22
Yep, you have the right idea on fiberfill... it slows the rear cone wave reflections as it permeates the fibers. This in turn, makes the sub behave as if in a larger box... but the internal volume increase is very small. The main reason I use fill, is to absorb some of the bass energy off the back cone for smoother bass response as there is less bass waver radiation, back to the cone to cause distortions.
Good research on the recommended sealed volumes. Seems to me, a sealed 0.88 cf/ chamber will do fine for both subs. No need to invert the Pro sub if you don't wish to. Just gives more opportunity to damage the sub with that much exposed. Would only gain ~0.67 cf of air space as this is the air displacement of a typical 12" sub.
From what you have stated so far, think this will work out fine.... 0.88cf/sub. If you get sloppy bass from the Eclipse speakers, can always add a few blocks of 2x4's to bring the internal chamber volume down.
Swez
Copyright ClubKnowledge 2009 * All Rights Reserved
