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Everything posted by Ricci

  1. Looks ok to me. I don't think you need the center puck if not using the star pattern. It's only used to anchor and align the star pattern bracing. Personally I'd leave the small braces in. They are for locking the baffle in place with the main brace and the port panel. There's not a lot of baffle area there and the baffle is swiss cheese. Not critical but I like to be sure the cab's are rock solid especially the baffle area. YMMV
  2. Excellent work. I look forward to your amp testing! How do you feel about the Pmillet unit so far? Also about how much money do you have into the test load unit?
  3. Both of these drivers are really good. The 18Ipal has similar xmax. It's basically a dead heat in that department. The BMS probably has the lowest functional power handling due to the lightest, smallest voice coil. The 18Ipal is the most efficient (lowest Qts)
  4. In a small room like yours and with relatively low volume playback,I'd recommend at least 2 compact sealed subs. 3 or 4 would be even better if you can spread them out around the room. This will even the response out over a wide listening area. If you can take a tape measure and figure out how big you would like the enclosures to be. Is a 21" cube ok? 18"? Smaller? There are a number of popular cost effective drivers if you want to DIY? Are you looking to DIY or are you looking to buy a complete sub? If going DIY you'll want DSP and you'll need an amp. It's cheaper to have the DSP i
  5. I'm planning to do some tests on mine but don't know when I'll get around to it. I'm more concerned with distortion in the lower midrange than the highs. I can't hear much past 16kHz anyway these days, so the HD of anything past 7 or 8kHz are probably of little audible consequence for me. The dual diaphragm mid CD's are intriguing for very high output pro apps but require a super tweeter past 8kHz or so. It makes them less useful for synergy or multi entry horn designs.
  6. Kolbrek's comments about the driver were part of the reason I looked into it. Actually that's not quite right. The voice coil diameter is 5" but the diaphragm itself is 7" diameter. The surface area and coil diameter is far greater than the usual 4" cd. Some of the dual diaphragm mids may be close or better it but those also do not cover the full bandwidth. Do you have links to detailed distortion measurements for these drivers? I've not seen any. CD's are notoriously difficult to compare as well since the lense used has such a profound effect on the behavior.
  7. They all have "optimized" phase plugs. Including the Celestions. What I mean is that the Axi2050 is supposed to be good compared to most 2" exit cd's in the 10-20kHz octave but the physics mean that while it may be good for a 2" cd it will never be as smooth in this octave as is possible with a smaller diaphragm and smaller exit. Most of the top octave output for large cd's is resonance/ breakup / beaming. Just goes with the territory. There are a lot of positives for the larger cd's though. Higher output, power handling, lower distortion, deeper extension. etc. As usual it's all tradeoff
  8. Gotcha...I thought I saw 402's in some pictures you posted. They are expensive. I bought a used pair and they were not cheap. I got quoted a new pair and it was much more. I hate to think what it would cost to get them landed over in the EU after VAT. Luckily I don't really care about looks for the warehouse system. I do like the weight savings of neo drivers. The 2445 JBL "tweeters" are over 30lbs. The Axi2050 is different from any of the other cd's out there. It's a relatively newly patented diaphragm shape. Supposedly it gets really wide bandwidth with no crossover and less brea
  9. So you currently have a single 12P80Fe in each? Did you ever decide on a cd? Also do you still have your K-402's? I picked up a set of K-402's last year to replace my JBL 2360's with 2445J's. Ended up deciding on the Axi2050 and picking those up too. I had it narrowed to those vs the Radian 950bePB. I was set to try the Radian but it turned out to be much more expensive and with a longer lead time than the Celestion. Unfortunately I haven't gotten my shit together and made the switch yet.
  10. Sure... there are many ways to skin the cat. I encourage experimentation. I went with the star pattern for the simple fact that all 8 "exits" would be identical. It was easier to model in Akabak. Also it doesn't have the center "pocket" in front of the driver center. I thought this might cause turbulence. Does it matter? Probably not. The original front had this type of bracing pattern.
  11. Don't put anything in the horn/slot section. The front phase of the driver. Sorry I worded that badly.
  12. Haha nice video... Yep. I can get almost any ported sub to make chuff noises with test signals and a big amp. If they say their sub won't they didn't try hard enough. With that said some speakers are a lot worse than others. Thankfully most of the time with music/movie/TV content it's triggered much less often. High power test tones at tuning will get them every time.
  13. Both should be correct. The rabbits should have enough extra clearance in them to accommodate joints other than 90deg.
  14. Yep... This is a 6th order BP type design. You don't want stuffing, just line the walls with some 1.5 or 2" / 50mm thick foam and staple gun it in there. Do the ported section only. All you are trying to do is knock down some of the high frequency reflections outside of the sub bandwidth. Try sticking your head inside of the unlined cab and snapping your fingers...There will be a lot of HF's and reflection. Repeat after lining and it's much much deader. Also it keeps the wire from rattling if they end up touching the cabinet wall. Keep the port entry clear though. A good 6" / 150mm cleara
  15. Making the cabs smaller will reduce the efficiency and sensitivity a little. Should not affect the FR shape or extension much. It's only 10mm. Make sure you check that the driver will still fit after subtracting 10mm though. A 21" driver frame is already very tight in this box width. Have you thought about adding a bit of extra wood to hold the grilles instead of modifying the cab width? I'm interested in seeing what you have going on with the steel baffles too. Good luck! I will see if I can get a hold of Kyle about your picture bandwidth questions.
  16. With 726cm of vent area and 35m/s max velocity, port compression should be minimal. If I had to guess I'd say about 2dB port compression and that is only at maximum output. Reducing the output 3dB does wonders. I hope no one is running cabs at maximum! If you do you need more cabs. Airspeed will grow with the lower tuning options. There is nothing that can be done about it due to the physics. Have you read Collo's works and the JBL whitepapers on ports? One take away is that larger vent area will support larger air speeds with less chuffing and compression. With the modern hi
  17. Sort of but it's more complicated than that. HR considers each boundary an infinite wall. This isn't true even with a bunch of cabs outdoors.
  18. Hey Kipman... the port area listed is exactly what the area of the vents are. There is no fudge factor. Your calculation must be off a bit. 24" width, two 18mm side panels and three 12mm vent dividers. Length is 102cm effective calculated off of the sketches inside of Solidworks. Of the port calculation styles you linked only the 3rd and 4th from the left are worth using. Mixing #3 and #4 is worthwhile. The rest are inaccurate. I've designed, built and tested a bunch of designs with similar ports and that's how I've determined what results in a close match. Use #3 from the attachment for
  19. Also that's a bunch of BLUE subs!
  20. The primary mechanism will be 8 bolts into the baffle face with inserts, or screws could be used. 3 other screws would come into the end grain of the cover struts. 1 each through the 2 sides and the top. The holes would be pre-drilled to avoid splitting. A 4th would be pre-drilled and run at a 45deg angle into the vent panel. The main holding force would be the fasteners into the baffle. The other 4 screws would mainly be to keep those 4 struts from vibrating. As shown here.
  21. I already factored in the extra proximity effect when I made my comments. That panel will need to be about 26cm to get the effective vent length in the sim. Looks like it is about 18 -20cm at most. Port bracing should always be accounted for. It reduces your effective vent area and multiple vents also tune a little higher than one big vent. At the end of the day we are probably talking a difference of a few Hz difference in the tuning, but even that can make a difference. S1 starts at the wall where the panels pinch together. Do you have 8 or 9 cm there before getting to the
  22. Do you still have the SKRAM? I'm interested. I need to get one to test.
  23. I think you are the first person who has said that the chest pound is missing. Is it possible that what you are looking for is occurring in frequencies that are above the sub band? What some guys would refer to as the MBM range (100-200Hz) Are you using them outdoors, at home, big venues? Is it possible that you have acoustics issues contributing?
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