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No.4

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  1. The deal on cherry is back on today for 24 hours on the 280f
  2. Just keep checking. They seem to rotate the same deals very few weeks. I am waiting for a deal on a cherry rp-440c. Fingers crossed.
  3. @Edgar I have definitely gone down the rabbit hole in a quest to find more info in this subject. Unfortunately most of the information I have found is geared towards building subs, but I think it is still useful in this application. I am focusing more on a flat response down to the winISD recommended tuning frequency, than trying to force lower output out of this box and driver. I modeled using both the BB4/SBB4 and QB3 configurations. I arrived at the same results with both configurations. I achieved good results with a tuning frequency of 50hz and a box volume of 3.441 ft3 . This volume of 3.441 ft3 was derived using internal dimensions of 26"H x 22.5"W x 12.5"D, then subtracting the rough volumes of the bracing, driver, networks and area consumed by the port. Port length was calculated to be 4.76"
  4. These have been sitting in the closet for two or more years now. If I recall when I purchased these they were considered a good fit for Cornscalas (I could be wrong, again this was a couple of years ago). I know there has been some discussion lately about these not being ideal as a replacement a Cornwall bin, but I am not really building a Cornwall bin anymore. Any loss in low frequency output will be supplemented with a sub or two.
  5. I modeled several different options for tuning frequency. All at 4 cubic feet with a port cross section of 1.5" x 5" light blue 36hz red 38hz green 40hz dark blue 45hz purple 48hz More research is needed to decide if the goal is to tune the box as low as possible at the expense of a few db output, or to tune higher to attain a flatter response. My hunch is that tuning lower is where I want to be because we are talking about a few db of output lost.l
  6. @Edgar First of all thank you. I was able to get winISD running on my beater PC and do some modeling. I played around with different volumes and tuning frequencies until I was able to get a flat output up to around 70hz. The port cross section has remained the same but winISD calls for a shorter depth for the 120 liter cab. Different sized cabs especially larger ones model a little higher output down into the 50-60hz range but this is the difference between one or two db at most. Adjusting the tuning frequency based on port cross section and cab volume makes the most difference in output. I am reading up on tuning frequency and its real effect on how low the cab will go. So far my limited understanding is that the tuning frequency is basically where the driver and the port interact. frequencies where the port is moving more air and the cone is traveling less, versus frequencies where the cone is moving further to make up for the ports inability to move enough air. (I could have this totally upside down, so if anyone has a better explanation please share it). winISD is pretty easy to use too, although it took me a second to realize I could change the units of measurement from metric to standard etc by clicking on them. I did quite a bit of converting on phone before I realized it. oops.
  7. @EdgarThank you for modeling both of those. I am going to see if my old mothballed laptop will run winISD.
  8. Understood. I have a Mac and I do not have admin rights to my work PC, so I am not able to use winISD. I am curious can winISD model a 120 liter box with 3, 1 1/2 x 5 x 7 1/2 ports with the kappa. I am curious to see what the results are. Same with the Cornwall 4. Using the internal dimensions of the CW4 and the same rough port measurements with the the k33.
  9. After some more thought I don't think this will be possible. This will push the kappa too far way from the the top of the cab. I am considering bringing the internal depth down from 14" to 12.5" Internal dimensions 26" H 22.5" W 12.5" D Total 4.23 ft3 Not accounting for internal bracing and networks. External dimensions 29" H + 2" base riser = 31" overall height 25.5" W 15.5"D + 3/4" baffle edge
  10. That is some great information! I don't think I have ever seen anyone go that far for a measurement. Thank you. Eminence recommends a port size of 79.85 in3 each for a round port. This gives a total of 159.7 in3 for recommended port volume for the kappa 15C. @Thunderball measurements gives us 45.77 in3 for each port and a total of 137.31 in3 for the Klipsch driver. The current size of the ports I am constructing are 56.25 in3 each, totaling 168.75 in3 . I may trim a little off the length of my port assembly to bring it a little closer to the eminence recommendation, but Im not sure if roughly 10 in3 will make that much of a difference. @jjptkdThanks for the link. I did watch the first part of the video before going to bed. I need to finish this today some time. Justin does recomend a 4 ft3 box over the roughly 6 ft3 . After doing a little thinking about that and looking again at the eminence site I am going to reduce the size of my box. I will not go all the way down to 4 ft3 , but I will definitely shave off some volume. Reducing the overall size will definitely help with the ongoing conversation at home about our house filling up with huge speakers. The eminence site also recommends a minimum box size of 2.58 ft3 for their large size box measurements, so going smaller should not hurt. I will have to some dimensional whittling this morning. I am also trying to decide where to put the networks. the first thought is obviously inside the cabinet, but I am considering making a cutout on the top of the cabinet that is sealed from the rest of the inside of the cab for them. this would further reduce the internal area of the cab. the top of the cab would have a large "window" that would cover the networks and the horn assembly would sit on top of it. This is just an idea at this point. the networks would be somewhat visible at this point if you are looking down behind the horns, but invisible from the front.
  11. LOL. You had me for a second there. good ol Jeff.
  12. Another member provided the rough measurements of the port. the center tube part is probably the most critical. 1 1/2" x 5" x & 7 1/2" = 56.25 in3 . This was measured from outside edge of each flare. the total length of the ports I am making are 7 1/2". Each end of the port will be 3/4" cut at 45 degrees to create the flare.
  13. MyRef FE LM3886 based chip amp LM4780 based integrated chip amp-audio sector boards. KT88 SET - parks audio clementine board These are the amplifiers I have built over the last ten years. It blows mind how quickly that time went by. The first amp is actually the second shown. It is the LM4780 based audio sector amp. this is basically 2 LM3886 in one package. This was when I thought I needed lots of power. The second was the MyRef type amp. This is a great amp and I would definitely like to build another some day. It had noise issues that I could not resolve. The case is currently in process of becoming an F5 (or at least has been in process for 5 or more years!). The third is a KT88 clementine SET. This has been my daily driver for several years. This is a fantastic amp that powered my La Scala clones with ease and now powers the dual heil wave guide on top of the Scala clone bins. I would love to build many other versions of this amp but the boards are out of print. Someday I will build point to point. I have a 300B project that is also half done sitting on my desk. My original goal was to build a nice DIY hifi item at least every year. Seeing how long the KT88s have been in use, I may need to consider replacing them at some point.
  14. Indeed. I will start the test with the ESN500 that I have on hand. My other option is DSP which may be a challenge to implement in the system that these are intended for.
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