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Fusion-12 Tempest cabinet questions

756 Views 7 Replies 3 Participants Last post by  rocksteady40
Hello All,

First off, I must thank all of the people that have contributed so much time and efforts into all of the SEOS designs. It unbelievable what has been accomplished! Thank You!

I would like to build a pair of Fusion-12 Tempest cabinets from scratch. Although I would like to buy the full kit, my financial limits prevent this :-(. Another reason is that I have been building a pair of Tractrix horns and I need a woofer. Hence building the cabinet from scratch. I want to keep the cabinet design the same so as to be able to change them to a full Tempest design later.

The dimensions of the cabinet are posted so I'm all set there, but I have two questions that I couldn't find the answers too after doing many searches.

First is, what are the port sizes? I did some reverse engineering based on a front view of the finished Tempest and I came up with an OD of 4”. This may translate to an ID of about 3.5” or so.

The length seems to be just a little shorter than the SEOS-12 horn, so about 6”. I checked PE but couldn't find anything close. Does anyone know the correct dimensions of the ports? Or better yet a source for them.

The second question is about filling/lining the cabinet. I don't remember seeing any description of what to do here. Some of the builds show stuffing so I guess there should be some.

Any help would be greatly appreciated. Thanks
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The kit cost less than the parts would cost. So if that's over the budget, and you wanted to switch out a woofer to something cheaper, it would completely change the speaker and crossover network. If you change parts of the speaker or change the front baffle (like spacing or recesses), it will also change the end result. You would likely be better off going with a cheaper kit versus changing one of the mid priced ones.
i'm not sure that i understand your plan. if the tempest parts are too much money, what parts do you intend to use?

fiberglass makes good stuffing for speaker cabinets.
Sorry I should have been more clear with my ideas. I have large horns that I have made and I need woofers for them. The horns will not be in the cabinets but rather on top of them. I will probably tun the cabinets upside down so that the woofers are closer to the horns.

The thought was to build Fusion-Tempest enclosures using the same Eminence Delta Pro-12A woofer and port sizes. I will add some blocks of wood to emulate the volume of the horn so that the net volume in the cabinet is the same. This will allow me to add the SEOS horns, CD's, and xovers later to yield a full up Tempest if I decide to do so. I understand that this will cost me more in the long run but it will give me what I need now and allow a possible upgrade path later. I hope this describes my thoughts clearer.
You would end up having to rebuild the cabinet because spacing relationships and driver depth between the CD, waveguide, and woofer would be very important. The designer doesn't just build around the parts, but also how the parts interact in the final box design.

As for tuning the Delta Pro for your current speaker design, there are many different port sizes, box sizes, and tuning frequencies you can shoot for depending on what your end goal is. And you can use many different port models. If you go to the Pars Express page that lists the Delta Pro, over on the right there's a downloadable file from Eminence that gives you quite a few different recommendations to build around. It really depends on what your end goal is.
Thanks for the sugesstion Erich. I'll look at the PE recomendations. Thank you also for all that you do to provide the SEOS designs to all of us DIY'ers.
i see. what were you planning for a crossover to your horn?
I'm using a CX3400. I built a pair of 250Hz flare round Tractrix horns which are flat down to 400Hz. I'm currently crossing them over at 500 to 600 Hz to an old pair of Pioneer CS-R700's which I am using as woofers. They are 12" and have an efficiency of 91dB but they are old and tired. I know, it sounds crazy, but it's a low budget operation so I'm using what I've accumulated over the years. I had done a fair amount of work on the horns before I found the SEOS project and wanted to finish them. They sound very good. I know that they don't have very good off axis response, but right now I have a very dead room with only one chair so I don't think that it matters much. I hope to have a home theater in the future and the SEOS designs are the speakers to use.

I am looking to get a good set of woofers to use with the horns. Looking at the various SEOS designs, I think that the Tempests wold be best for me in the future. So I was thinking about building the cabinet verbatim but w/o the horn. I can make the face detachable so that if I do go for the Tempests, I have the correct box and woofer ready to go. Then all I need to do is add the horn and passive crossover and away I go.
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