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radulescu_paul_mircea

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About radulescu_paul_mircea

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  1. radulescu_paul_mircea

    Ricci's Skhorn Subwoofer & Files

    The drivers used are 21Ipal , yes . The drivers in F221 are an OEM combination from Fane with Precision Devices, neo driver. The subs are extremely loud , but not on their own . I did some tests regarding the frequency response of a single vs double F221. The tests have revealed me something really cool. The magnitude response stays the same, it just goes up with 6 dB ,double the sound pressure, but the maximum clean output CEA bursts results go higher. Practically a better acoutic impedance will give better load and lower excursion. Plus, the electrical impedance goes a bit higher on average so the real sensitivity for 1 W is increasing CEA-2010 max burst, 2 m ground plane , measured at 4 and 8 meters to avoid mic clipping 1*F221 1 channel of ffa10000 25- 107.9 30-116.1 31.5- 118 40-133.1 50-135.7 60-137.1 80-143.2 100-142.6 2*F221, 2 channels of FFA10000 25- 116.8 30-125.5 31.5-128.5 40-141.5 50-143.6 60-144.7 80-147.9 100-148.1
  2. radulescu_paul_mircea

    Ricci's Skhorn Subwoofer & Files

    Sensitivity referenced at 1W/1 m measured at 4 meters, 2.83 V in 0.5 ohms on BPH221 vs 28.3 V in two 8 Ohm F121subs
  3. radulescu_paul_mircea

    Ricci's Skhorn Subwoofer & Files

    This is the excursion of two 21Ipal in series in the same enclosure, with the CMS having a difference of only 10% between them. The place where I did these tests is a parking lot from an old factory where we have the workshop. It is surrounded only by other workshops and some offices that were closed at that moment. The parking lot is big, around 50 by 60 meters and if I go as close to the middle as I can, the frequency resolution is very good and I can get good accuracy down to 20 Hz.
  4. radulescu_paul_mircea

    Ricci's Skhorn Subwoofer & Files

    @Ricci Thank you for the reply. I am a bit concerned about that behavior, it is not related to the loading in the horn,but the behavior of two reactive loads linked in series, that see different voltages based on the difference in impedance and electrical phase. Anyway, the subs are extremely potent, the content below 40 is so present and clean! I wouldn't be afraid to put them next to Funktion One F132. Unfortunately the clone power supply was not up for the task and after less than an hour with a sub on each channel, it died. Then I tested them with 2 Crown 5002VZ in parallel mode, each sub on a channel and the deepest bass was achieved , it could sustain 85 volts in impedance minimums without any sign of backing up, but the punch and headroom was smaller than with the clone. The next step is to completely change the bracings, build another pair, load them up with 21ID and IPal modules, buy a K20 and then compare them 2 vs 2 and see what happens, whichever is best. I bet on the K20+ 21Ipal combination but one could never be sure until I get the tests results. I would love to use these with SpeakerPower modules, each driver on its own amp, with 4-6 kw, because IMO , that's when the party is really starting. Unfortunately it's hard to buy them from the states.
  5. radulescu_paul_mircea

    Ricci's Skhorn Subwoofer & Files

    @Ricci Did you have any problems linking the drivers in series on a single amp? From what I get in sims and in free air tests, the excursion goes mad if the parameters are just a bit different on the 2 drivers. Also the loading can change the behavior
  6. radulescu_paul_mircea

    Ricci's Skhorn Subwoofer & Files

    So after all, the CEA-2010 from REW is showing the peak pressure level of the frequency tested, not a mean, so one one shouldn't add another 3 dB to get a peak.
  7. radulescu_paul_mircea

    Ricci's Skhorn Subwoofer & Files

    This is the final measurement before painting and adding some damping materials
  8. radulescu_paul_mircea

    Ricci's Skhorn Subwoofer & Files

    After adding two more braces from one side to the other, I did another round d of bursts. 4 meters, added 6 dB for 2 meters equivalent. 25-126.7 dB 30-136.7 dB 31,5- 137.3 db 40-141,4 dB? 50-144.2 dB? 80-146.4dB? 90-144.9 dB? 100-144,2dB ? The sensitivity at 30 Hz is 99.8 dB at 4 meters at 2.83 V. Just a dB higher than the original.
  9. radulescu_paul_mircea

    Ricci's Skhorn Subwoofer & Files

    His 3 brothers are on their way, I'll have 2 with 21Ipal and 2 with 21ID but with slightly modified bracings. This one didn't behave as I wanted it to and there was a strong vibration on the large panels so I need to add 3 more pieces of wood from one side to the other. Another problem is the weight, at 165 kg, it is pretty hard to manage. After all , I will not build the back ones for cardioid configuration, I'll use them as they are. These are the test enclosures, to learn and to try things. They will be for comparing my new designs and to see what kind of improvements I can manage to squeeze , if I go bigger but I'll keep the dimensions constraint to 140*140*70/75 cm...
  10. radulescu_paul_mircea

    Ricci's Skhorn Subwoofer & Files

    Each driver on one FP14000 clone chanel, CEA2010 burst, calibrated mic, 4 meters, added 6dB for 2 m equivalent. Where you see a question mark, the amp turned itself off for protection. the closest buildig was at about 10 meters behind the sub. Bph221 25-124.1dB 31,5-135,1 dB 40-141,1 dB 50-144 dB? 80-145.3 dB? 90-144.9 dB? 100-144,2dB ?
  11. radulescu_paul_mircea

    New additions for db site (need feedback)

    DB site is not working? I get the error "Connection not private"
  12. radulescu_paul_mircea

    Ricci's Skhorn Subwoofer & Files

    140*100*70 cm .
  13. radulescu_paul_mircea

    Ricci's Skhorn Subwoofer & Files

    These are the modifications i made to this design, it is based on my sketches. I changed all the bracing, it was easier to make all of them with constant width because of the bigger width. The much bigger back chamber will surely increase the efficiency and power under 45 hz, I didn't feel the need to improve the horn on this one, it is good enough with just 20 cm extra length and an S1 correction. the material is already being cut
  14. radulescu_paul_mircea

    Ricci's Skhorn Subwoofer & Files

    Already ordered some wood, in fact a lot, I needed to order more to get the best price and I also need it for my other projects. I thought a lot of what you said and the sub would weight too much to be practical. So I decided to go modular. The idea is to make two SKHorns , but the depth will be 40" and the width 28", and port tuning will be a little higher , at 34 hz approximately, Just to get the best deep end I can, but also to match the top end a bit. The back enclosure will be an Ss15 based design, where I try to match the phase as well as I can, but I need the best efficiency to be centered around 50 Hz if I can, because I will make an end-fire configuration with that center frequency and the response of the front enclosure will have a high shelving in the back of it, so the frequency response for not need to match . The two enclosures will be installed back to back with screws buried on the sides . I wanted to use an electromagnet like the ones for doors , but that would complicate things a bit and unfortunately I'm a bit short on time I ended up with end-fire instead of gradient configuration after I did a very cool experiment. I put the RTA I'm REW on infinite averaging for a 5 hours set only with the music they are playing and the conclusion was that the energy is centered at 52 hz with a difference of 6 dB compared to the 40-110 hz band. So if I can get the attenuation of -15-20 dB at 52 hz in the very far field, over 100 meters distance in the back of the speakers, compared to a normal setup, it will be extremely helpful. I've already got my drivers, the difference between the B&C and the 21ID is night and day, power handling, excursion, shear mass, thermal inertia etc. But they are both extremely well.made drivers, with different applications for the same approach. The plan is to build these speakers for use in this application and to use them for comparing my own designs which will be build in the next month. I'll post some pictures when I'll start building
  15. radulescu_paul_mircea

    Ricci's Skhorn Subwoofer & Files

    The drivers are already here! The 21ID is so small and light compared to the 21Ipal.the cone is much softer, also, the coil is way smaller, with a much thinner wire and it gets hot more quickly. Probably twice as fast. The driver gets very noisy after about 3.5 cm excursion pk-pk , in comparison the B&C can travel about 5 cm before any strong noise . We clearly have a winner here, but that was not what I wanted to do. @Ricci you are right, the setup is a bit stupid proof, it's easier to get it right and to avoid any tempering with the setup. The decision is not final and it's pretty hard to get the fold good enough to match the phase and response of the front part. I also wanted to put the port and the horn in the center to get the acoustic path as close as possible vertically and horizontally
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