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Ricci

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Everything posted by Ricci

  1. Ricci

    Vortex & Kraken

    Here's my random thoughts. Shorting sleeve is mentioned but the 1kHz Le rating is way up there at over 2X the Re. Also the shape of the impedance curves shown indicate a very sharp increase in impedance vs freq above the minimum imp above resonance. Indicates a lot of inductance also. Heavy 5" coil and a huge motor with lots of steel. They have not posted the Zma data for download yet, which would allow it to be analyzed with Bolserst's semi inductance excel program to back out the semi Le specs for modeling. Shipping weight is listed at 115lbs. I suspect these drivers are in the 90-100lb range. Two or 3 times as heavy as the pro 21's. Can't see anyone using the Vortex 21 for pro audio work with that kinda weight. Drivers that heavy are a PITA to deal with especially in multiples. Imagine a double 21... Both drivers seem to be nearly identical. They model almost exactly the same except that the Vortex has slightly higher efficiency and upper bass due to the lighter mms. Most of that is probably just from switching surround types and perhaps the cone or dust-cap. The rest of the spec comparison and specs lead me to believe that the motor, frame, coil and spiders are identical. It's possible that the roll surround is much better behaved at high excursion than the traditional pro type (less noise more linear). If not I don't see a reason to pick the Kraken other than if you want that type of look. The Vortex is higher sensitivity and efficiency with apparently the same amount of excursion and it's a tiny amount lighter. Judging from the cutaway pics it looks like the top plate is about 15mm and the coil is about a 45mm wind height. Coil overhang would give 15mm overhag with no adder. 1/3rd gap adder would put it at 20mm one way which is close to the claimed spec. The coil would leave the gap at 30mm one way. Unless there is a lot of fringe field and overshoot the maximum excursion is done there and also sound horrendously distorted by that point. Of course I'm speculating based on an un-detailed drawing but this should be close. Spiders don't appear to be mirrored. There is mention of a warning system to prevent damage. I believe this is the ring shown under the bottom spider sticking up above the top plate. Looks like the bottom spider will contact this a few mm before the bottom triple joint would contact the top plate. This will probably sound very bad but not be immediately damaging. It looks like the bottom spider triple joint would contact the top plate around 30-32mm in. I'm guessing the spider will contact the ring around 27 or 28mm incursion based on that. Since the coil would leave the gap completely at 30mm I don't think it will be easy to push these drivers that far anyway. Spec wise I think these look good. They have a low Qts and high efficiency. EQ is used on everything these days and the goal is usually more bass from less space. The pricing also looks good especially in multiples. My biggest gripe would really be the 100lb weight followed by the question mark of how bad the inductance is.
  2. Should work fine with 4 8ohm drivers.
  3. Let us know how it goes. On both accounts.
  4. Ricci

    AE Techron

    I did. The old 7560's which I believe were the same as the Crown M600 and a couple of other re-badges. It's been a long time but it was something like 1500w burst into 4 ohm and 1000w for a very long time and would do it at 20Hz. Doesn't seem like much these days. These aren't really amplifiers intended for "music" signals. These are industrial grade equipment for labs, measurements, running motors, MRI's, etc. HEAVY loads. They do audio just fine but are WAY overkill for bumping some music. Kinda like taking a Mack tri-axle dump truck to pick up 100lbs of mulch. I love how they rate their amps and provide all of the engineering specs. Compare their data sheets to those for Behringer or Yamaha amps. This is how gear used to be spec'd. I wish it still was. Amps really should be rated in terms of voltage and current capability into various loads at different frequencies IMHO. A 7810 or 7796 is a monster power source even if some 20lb amps produce more power on paper. The ratings are MUCH different. Yes they are heavy as hell. They have to be. You'll never get this type of ruggedness and sustained power output out of a 20lb amp. If I was filthy rich I'd have a stack of these installed on 3 phase to run the subs, just because.
  5. This would be an interesting design. If you can try to use at least a 6" port for each driver. (180cm2 area). Dual opposing the driver will keep cabinet vibration down from the reciprocating driver mass.
  6. Ricci

    Rob's Amp tests

    Rev 2 to Rev 10...Lot's of refinement along the way it seems. Good luck!
  7. Ricci

    Eminence NSW6021-6

    Agreed. Could be a loose shorting ring even. There's a lot going on in the motor and gap area. Could be the spiders not glued fully also.
  8. Hey...Welcome to the site. The first info needed will be details help anyone give advice going forward. Budget? Planned use? Live sound / HT / Car audio etc... Size? Restrictions, shape, etc. Weight? Is this an issue? Amplification? Will it be an NU1000 or multiple LG 14000's? What frequency range of coverage is desired?
  9. Kipman I'll try to look into the user data limits with Kyle. It may be that you've maxed yours out rather than a hard limit on the size of the pics. The car audio guys have been strapping multiple amps together to drive a single load for years. It's rare in pro audio anymore. Seems to be mostly back in the 80's and 90's. I've always heard that it can get messy if the amps gains aren't matched correctly. No hands on experience with this though.
  10. Ricci

    Eminence NSW6021-6

    Yep...The 21 Klippel data is from Eminence. I would've preferred to see it done by RedRock but a lot of the time RR seems to cut the data capture off before a long stroke driver is really pushed. They don't seem to ever go past 15mm so the data may not have been as indicative. The Eminence data certainly looks great. The Xmax based on the Klippel defined limits for subs is almost 19mm based on all 3 criteria. I was surprised by the suspension behavior. I knew the spider choice and arrangement was good but I thought the triple roll surround would start to tighten earlier.
  11. Should be fine. It'll only have a minor effect that would probably require measurements to notice.
  12. You would be looking at just 1dB or so. It won't be a huge amount. Also it would slightly change the tuning and relationship of the back chamber to the front expansion.
  13. Hmmm. They seem to work fine for me. Do you mean the amp test links in the first post?
  14. Ricci

    Rob's Amp tests

    Here's my wish-list for amplifier power testing. If it were me I'd not test full power sine waves any longer than 5 seconds or maybe 10sec if you really want something a bit longer. There's no point. Even the most dense EDM music has breaks and is not anywhere near 100% duty cycle averaged over 10 seconds. If somebody really needs sustained multi KW power it's probably not for music or HT and it's time to look at an AETechron. Definitely no need for 2 minute full power tests IMHO. Plus as you say that'll get expensive when things go BANG! I'd like to see a few different frequencies tested. 1kHz has been standard for years so I get that but on these huge tour amps that are used for subs I don't think it represents the use very well. Is anyone dumping 10+kW peaks at 1kHz? That's not a concert or theater I'd want to attend. I'd like to see 50Hz or 63Hz used to sim kick drums and typical music bass and 10 or 16Hz for judgment of the deep bass power. Most amps wilt at those deep frequencies. There's almost always less power in the bass. Some amps hold up better than others but it's hard to tell from the 1kHz testing. Like I mentioned earlier I'd like to see something like this. 1kHz: 1 cycle burst (Short term output)/ 6.5 cycle CEA-2010 signal burst (Typical music content output) / 5 second sine wave power vs time (long term output) 50Hz: Repeat above. 10Hz: Repeat above 16kHz: Repeat above to gauge HF capability. The duration of the short term signals is longer for the bass frequencies as it should be. 1 cycle at 50Hz is 20ms and the CEA-2010 burst is 130ms. At 10Hz one cycle is 100ms and it's 650ms for the CEA-2010 burst, so it will be much tougher at the deeper frequencies. At 1kHz there is likely to be no difference between a 1 cycle or 6.5 cycle test. They are both so short in duration .I don't see anything less than a full wave cycle as useful data for the bass range though. The CEA-2010 signal is included in REW's tone generator, Clio and Don Keele's Igor pro program. It wouldn't be hard to sample it for use in other ways. Thanks for the data and discussion. Keep up the good work.
  15. MomoTon, The bracing should be fine. You can't reduce the width of the cabinet really. The 21.5" frame diameter of the drivers plus the wall thickness doesn't leave much to gain there. The depth could be reduced as well as the enclosure height but you will be reducing volume for the ported chamber and the ports. You will have to change the port size/length in order to maintain the same tunings and low bass efficiency will be reduced and vent velocity would go up most likely due to smaller vent area. I look forward to seeing your finished project with the CF. This sounds like an adventurous build.
  16. Ricci

    Rob's Amp tests

    Yep...Based on previous tests on various clones the burst power is huge and should meet spec but true sustained power is about 4kw give or take which will eventually throttle back even more. There really isn't enough in the AC line to support more sustained power in most cases unless on 240v with large breaker so most of the big "tour" grade amps cap out at about the same sustained power. Even multiple speakers really cannot handle that kind of sustained power anyway. Some of the old "iron" amps would do sustained power for at least a few seconds but the power ratings were lower and again you better bring a stout AC line. IMHO amp power ratings should be based on duration of a 1 cycle minimum for burst, 6.5 cycle shaped CEA-2010 signal as a short term rating and minimum 3 seconds sustained for long term. That's one thing that the name brand tour amps seem to do better than the clones is protections from blowing into tough loads.
  17. Ricci

    Rob's Amp tests

    Good stuff and thanks. The load bank investment wasn't bad at all. Usually when you see distortion creep up abruptly in electronics something in the chain is at the onset of clipping. Measurements for the Pmillet look quite good. I look forward to your amp tests!
  18. 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
  19. Ricci

    Rob's Amp tests

    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?
  20. 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)
  21. 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 in the amp. The Behringer NX3000DSP or 6000 version are popular and cost effective. The fans are LOUD though but they can be modded with quieter fans. The amp that Kipman linked seems like a good option also. You'll also want to be able to measure your response in room to help dial in the dsp for the subs and integrate them into the rest of the sound system. REW is popular and free. All you need is a decent measurement mic and a sound card. The Umik system is poplar too. It's surprisingly cheap to get a setup going. $100 can do it.
  22. 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.
  23. 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.
  24. 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 tradeoffs. Also gating can allow for useful measurements of high and mid frequencies in room.
  25. 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 breakup than normal diaphragm shapes / materials. I've heard that as usual for a 2" exit cd the air above 14 or 15kHz isn't as good as a smaller cd or a Be unit but the midrange is supposed to be very good. Also it has huge surface area and claims to be able to get down to 300Hz. What is slightly irritating is I contacted PE about the Axi2050 6 months ago and they said it could not be special ordered from Celestion due to it being OEM only. Now it is on their website for sale. 😒 Oh well...I still paid less for it delivered all of the way from the UK. What kind of help are you needing with REW?
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