Page 5 of 21 FirstFirst ... 3456715 ... LastLast
Results 61 to 75 of 314

Thread: KM2

  1. #61
    Senior Member Anti K's Avatar
    Join Date
    Oct 2017
    Location
    Estonia
    Posts
    126
    Quote Originally Posted by Robh3606 View Post
    Looking at the vintage 4 ways the best part of those systems in my mind were the 10" drivers used.
    Yes. And, thats why, if You take a look at waterfalls then even best CD-s does not look so nice below ca 1200Hz. It makes you quicly think that there has to be a crossover at 1,2kHz region and then it's already obvoius: need a 10'' mid.
    One more cross, one more phase mess, how to make it all sing like one element?

    Like You sayd Yourselt, Rob, when You buid Your stuff. Several CD-s measured same but sounded differend. Some nicely, effortless, some not - same graph.

    I think ... I do not why but have such a strange feeling, there is a tiny possibility: JBL made some prototypes before they sent 9900 and 66000 into production line. I think this is a tiny possibility they listened them a'bit before, Yo

    Thanks, but no thanks. Fellow Rob and Dr.db, I'll pass the 10'' part. Not because it's a bad suggestion but;
    Two reasons:
    - have in mind build up full system from zero: enclosures, drivers (buyable ones, new ones), dsp-board, Purify boards for higher, nCores(as they are bridgeable) for lows, all these all in my own-made racks. Plenty of fun ... I'd stay with 3-way this time.
    - another reason (a good one): if JBL itselt already placed 15'' below CD in ones of their best contemporary systems, in ones best systems on the Planet, than I do not want to try be smarter (I'm not crazy) but just try to clone - or not even clone - but rather take hints from there, the arrangement.

    The exercise I took is ALREADY higher than me. If I want to play it Ok I have to do nothing but avoid mistakes. Simple!
    But mathematics says: the probability of errors is related to the square of the number of elements.
    The speaker. One cross, on error-possibility. Two crosses - 4 possibilities. 3 crosses (4-way) = 9 possibilities of errors. Simple!

    I think I'm not able to make it right. I'll go basically 2-way. Low end is supportive - in the region cannot be heard the direction of sound. And Dirac Live probably helps me as well with the last one...

    These 'veneered monsters', is a 'calculated simlicity' however they look like comlicated monsters. if take it in 'molecules', it's a simpliest way system with fewest possibilities of mistakes - one important cross: a two-way system. 4CD+15W.

    Andy
    Last edited by Anti K; 02-01-2021 at 01:46 AM. Reason: type mistakes

  2. #62
    Senior Member ivica's Avatar
    Join Date
    Jan 2008
    Location
    serbia
    Posts
    1,679

    JBL 476Be vs 2450, 2451

    Quote Originally Posted by Anti K View Post
    ...........

    Then, new topic: 476
    What is so special in there? .......
    Hi Anti K,

    I think the main difference between 476Be driver and (vs) 2450-1.5 or 2451 equipped with Be(TruExtent diaphragm) is Be diaphragm suspension, as on 476Be the suspension is Be made in the shape as can be seen on other JBL 4" diaphragm ("diamond-shaped" 2441,2445,2446,2450, 2451...), as it has been explained in JBL Technical Notes
    can be seen on the attached picture:
    http://www.audioheritage.org/vbullet...l=1#post370262

    when D16R2441 has been introduced, such suspension would allow better ultra high frequencies response,
    look at fig.4 on the JBL_Tehn_Notes_Vol.1_No.8 (explanation sec.4. A and sec.4.B)

    http://www.audioheritage.org/vbullet...ume-1-Number-8

    especially if applied copper short-ring in the driver magnetic path (just to reduce the influence of the voice coil impedance in high frequency). Unfortunately the availability of the JBL original Be diaphragms is a problem, and its price would be something that is "over budget".

    On my opinion, thinking about JBL_476Be application, would be finding proper horn that would be applied, as most of them (while neglecting M2 horn) would pronounce ultra high beaming over 12kHz. I think that only M2 horn would overcome such problem, but as can be seen M2 horn has not good driver loading under 1200Hz, but for "home listening applications", may be, M2&476Be can be used from about 700Hz applying sharper network ( LR-4_order ). Fortunately, JBL 2226Nd can be used in such combination as very good mid-bass driver.
    For sure sub-buss up to 100Hz, would be welcome (I would prefer 18" bass driver there).
    May be "helper bass" combination 2226Nd-1 and 2226Nd is possible solution too, as MR_Widget (http://www.audioheritage.org/vbullet...hp?3-Mr-Widget), has been experienced

    Regards
    ivica

  3. #63
    Senior Member grumpy's Avatar
    Join Date
    Oct 2003
    Location
    SoCal
    Posts
    5,638
    2226Nd? ... say after me, 2216Nd... 2216Nd... 2216Nd

  4. #64
    Senior Member Anti K's Avatar
    Join Date
    Oct 2017
    Location
    Estonia
    Posts
    126
    Quote Originally Posted by ivica View Post
    M2&476Be can be used from about 700Hz applying sharper network ( LR-4_order )
    Yes.
    This is a part of plan, a sharp slope both of them, LP and HP

    If compare, the DD66000 has 476Be crossed at 750Hz and newer DD67000 the crosspoint is rised to 850Hz.
    For me it talks, if give to the driver some 'space' or 'vacation' in lower part, same 'item' works better at high section.
    For same reason I plan 'free' the 2216Nd from lowest 3 octaves.

    Was thinking one more thing:
    In these stellar systems AL1500 Woofer has go as high as 850 (even 900Hx in K2S9900). No matter it's AlNiCo or what, just, 140gram of matter has to vibrate almost thousand times in second, sinusoidally.
    So: 1500AL Fs is 19Hz and it has to work 20-900Hz.
    2216Nd has 2X higher Fs, 36Hz and would work ca 80-850Hz.
    Both Woofers have same Moving mass.
    And Neo magnet is tough and differential drive a wise construction. Sounds promising (to me).

  5. #65
    Senior Member
    Join Date
    Oct 2003
    Location
    Texas
    Posts
    1,861
    Unless you have a source for these esoteric drivers like the 476Be and any of the 1500/01/AL/AL-1 etc, I'd use what's more commonly available. The 2216Nd is the 2235 of today, they are used in consumer and pro and should have support for a while at least. 2451 motors are plentiful used, stuff a decent diaphragm in one of those and go on down the road. Both are nice pieces of kit and can actually be purchased.

  6. #66
    Administrator Robh3606's Avatar
    Join Date
    Apr 2003
    Location
    Rocinante
    Posts
    8,570
    I think that only M2 horn would overcome such problem, but as can be seen M2 horn has not good driver loading under 1200Hz, but for "home listening applications", may be, M2&476Be can be used from about 700Hz applying sharper network ( LR-4_order ).
    Hello Ivica

    Why do you think the loading is not good below 1200Hz with the M2 horn?? I had no problem at all crossing at 700Hz 18db electrical slopes. Above 10K the M2 has directivity issues just like any other horn with a 1.5" throat. The knuckles help but the DI goes up and when doing measurements you can see this. Look at the power response curve.

    Rob
    "I could be arguing in my spare time"

  7. #67
    Senior Member ivica's Avatar
    Join Date
    Jan 2008
    Location
    serbia
    Posts
    1,679

    245x & M2 horn

    Quote Originally Posted by Robh3606 View Post
    Hello Ivica

    Why do you think the loading is not good below 1200Hz with the M2 horn?? I had no problem at all crossing at 700Hz 18db electrical slopes. Above 10K the M2 has directivity issues just like any other horn with a 1.5" throat. The knuckles help but the DI goes up and when doing measurements you can see this. Look at the power response curve.

    Rob
    Hi Robh3606,

    Looking at the measurements, shown by our forum member sebackman ( http://www.audioheritage.org/vbullet...?600-sebackman )

    http://www.audioheritage.org/vbullet...l=1#post373896
    http://www.audioheritage.org/vbullet...1&d=1428338852


    it seems to me that the LF driver loading by M2 horn is not so good, but as I have said, using sharp network and so called "home listening application" I would not expect any problem about diaphragm suspension, especially if it is not metal made.
    Some of my "observations" were shown in:
    http://www.audioheritage.org/vbullet...l=1#post375970

    We have to be aware that for twice lower frequency the diaphragm amplitude would be 4 (four) times larger, under the same driver&horn combo. If the sensitivity is less for lower frequencies, then even larger diaphragm amplitude would be in order to produce 'flat' response.
    Due to that "fact" using JBL 476Be/Mg diaphragm ( our friend 4313B has) with 'diamond-shape suspension' under 1kHz can be a (destructive) problem on high levels, but for the D2430K, Radian-AL or Truextent-Be with a polymer suspension, I believe, would not be a problem. I think that even GT had mentioned some kind of THD rise in the lover mid of the M2&D2 combo on M2 speakers.

    It would be nice if You can show us THD measurements for driver&horn (M2) combo You have been applied.


    Regards
    ivica
    Attached Images Attached Images  

  8. #68
    Administrator Robh3606's Avatar
    Join Date
    Apr 2003
    Location
    Rocinante
    Posts
    8,570
    it seems to me that the LF driver loading by M2 horn is not so good, but as I have said, using sharp network and so called "home listening application" I would not expect any problem about diaphragm suspension, especially if it is not metal made.
    Some of my "observations" were shown in:
    http://www.audioheritage.org/vbullet...l=1#post375970

    Hello Ivica

    Thanks for posting that.

    Something is not right?? We must be measuring under different conditions. I don't show any significant roll off until about 700Hz. I got the same measurements on 2 different calibrated measurement systems. I am wondering if he had a protection cap or some network in place when he did the measurement.

    Looking at the measurement I can understand why you said that. I did mine with no protection cap.
    Attached Images Attached Images  
    "I could be arguing in my spare time"

  9. #69
    Senior Member ivica's Avatar
    Join Date
    Jan 2008
    Location
    serbia
    Posts
    1,679

    476Mg & M2 horn

    Quote Originally Posted by Robh3606 View Post
    Hello Ivica

    Thanks for posting that.

    Something is not right?? We must be measuring under different conditions. I don't show any significant roll off until about 700Hz. I got the same measurements on 2 different calibrated measurement systems. I am wondering if he had a protection cap or some network in place when he did the measurement.

    Looking at the measurement I can understand why you said that. I did mine with no protection cap.
    Hi Robh3606,

    From Your measurements, it can be concluded that You are absolute right to use it over 700Hz. May be the differences are in the diaphragm type, as Yours are JBL 476Mg type.
    Can You show us horizontal dispersion data, if You have ?

    Regards
    Ivica

    Ivica

  10. #70
    Senior Member
    Join Date
    Apr 2003
    Location
    GTA, Ont.
    Posts
    4,839
    Quote Originally Posted by ivica View Post
    Hi Robh3606,

    From Your measurements, it can be concluded that You are absolute right to use it over 700Hz. May be the differences are in the diaphragm type, as Yours are JBL 476Mg type.
    Can You show us horizontal dispersion data, if You have ?

    Regards
    Ivica

    Ivica
    Perhaps you should simply ask "sebackman" about what you're seeing to help straighten this out.



    My guess it's a simple case of one using too small a window with the measuring software ( justMLS ).

    From the same thread ( you referenced ), here's the same horn and driver measured with a 20ms window ( I'll bet the picture above that you like to refer to, used something like a 5ms window ).
    - Some simple shelving EQ has been added here ( according to the posted info ) to flatten the raw response.

    Quote Originally Posted by sebackman
    M2 waveguide with 2451SL/475Nd 20ms XO 544Hz LR24 100cm out with crude light eq (12db HS). Not too shabby



  11. #71
    Member sebackman's Avatar
    Join Date
    Feb 2004
    Location
    Europe
    Posts
    562
    Here I am :-)

    Earl is right. From the post after the one you quoted Ivica there is data on the measure posted. I used a 4ms window which does not contain much data below 1k. A short window is used to reduce interference from the room in MLS measuring.

    My findings show that the M2 WG provides good coupling down to about 700Hz and can probably be used lower with EQ. However I don't know how it sounds that low. I typically XO at 8-900Hz. -And about 1k for the VTX WG which sound surprisingly similar, at a fraction of the cost. I'm not saying they are interchangeable but it's a real good run for the money in a smaller cabinet that can be raised to listening height.

    JeffW, I would argue that 2216 is not the new 2235. It is a new breed of 15" that can do LF and Mid up to 1k in a good way and we have not really had that before 2216. Maybe in (LE1400Nd/LE1400H, 14" I know) AL1500 or 1500FE.

    There are several drivers that can measure up to 2216 in LF, I would argue that there are also drivers that can keep up in Mid. But none than can do both with the same panache. This gives us the opportunity to create a 2-way that sounds excellent, be it the M2 or the 4367 (or home brewed). Wonderful. A bit like JBL tried with DMS-1 with limited success.

    Anti K, M2 is a "system" where every part is part of the success. If you start altering things (even little things) it will not be an M2, and in most cases not even close. The beauty of doing so anyway, is that you can chose any combination of drivers and cabinet that suits your ears and wallet. That is what I do.

    Having listened to M2 and had them here (albeit clones) I can say that there is huge amounts of work and time going into getting a different combination (drivers, cabinet and DSP settings) to work as well together as in M2. If you are skilled with designing and measuring acoustics you can get there or at least close (enough). But if not, I suggest to "copy" a proven design of your liking to safeguard some kind of return on investment of time and money.

    The time where we could assemble our own DIY set of drivers and create a system that is as good (or better) as what is available on the market has passed with these new complex system designs.

    Manufacturers like JBL invests a lot of time and money to build systems like M2 and alike. It takes even them years to get there. -And then they have access to large anechoic chambers with computer aided measuring systems for consistency, an army of skilled and experienced people, unlimited access to driver units to try out and not least access to rapid prototyping.

    Most of us have none of that, except for some, not least active here on LH, that do have a long experience and lots of knowledge.

    Many people here (and elsewhere) have made wonderful DIY systems that no doubt produce excellent results but they have been experienced individuals from the start and have spent a lot of time to get it right.

    Regarding subwoofers I would look at having at least 4 woofers spread out in the listening room (placed at the middle of each boundary/wall) to avoid room nodes. I also agree with Widget to investigate the possibility to turn you listening space 90 degrees in either direction. Pref away from the windows.

    Regarding drivers, some of us prefer 4" drivers for various reasons. M2 is designed with a D2 driver and if you deviate from that you are on your own to develop XO/EQ settings. Be's are very transparent but I would sacrifice that to build a 2-way to avoid the UHF tweeter (cost and complexity). Mg is no doubt an excellent driver for a 2-way if you can find drivers and you wallet concur with the choice. I would argue that you can get to a similar level with a good set of 2451 cores, felt back cap and professionally installed (measured) SL diaphragms by using a good DSP.

    I keep getting into these long rants. Sorry.

    In short. Accept a "good enough system" with the drivers/cabinets of your choice or use a proven design. If you chose the first route, make sure you have lots of time available. And good measuring tools.

    Kind regards
    //Rob
    The solution to the problem changes the problem.
    -And always remember that all of your equipment was made by the lowest bidder

  12. #72
    Senior Member
    Join Date
    Apr 2003
    Location
    GTA, Ont.
    Posts
    4,839
    Thanks Rob for all the clarifications.

    It's very much appreciated!


  13. #73
    Senior Member
    Join Date
    Oct 2003
    Location
    Texas
    Posts
    1,861
    Quote Originally Posted by sebackman View Post

    JeffW, I would argue that 2216 is not the new 2235. It is a new breed of 15" that can do LF and Mid up to 1k in a good way and we have not really had that before 2216. Maybe in (LE1400Nd/LE1400H, 14" I know) AL1500 or 1500FE.
    I meant the new 2235 in context of a pro 15" being deployed in good numbers. The other 14 and 15 inch drivers you mention - are they readily available for purchase new and have replacement part support? The 2216 is and does. The 4430 was a 2-way 15" that used a 2235 and was in production for quite some time, so 15" 2-ways aren't new. I don't claim the 4430 is equal to the M2 or that 2235 is equal to the 2216, it's just that unless I had a set of drivers and a set of spares, I wouldn't design a system around limited production drivers with no after sale support.

    The 2216, like the 2235 before, is being produced in large enough numbers on the pro side that it should have some support down the road, that was the reason for my comparison - not the sonic attributes.

  14. #74
    Administrator Mr. Widget's Avatar
    Join Date
    Apr 2003
    Location
    San Francisco
    Posts
    10,782
    Quote Originally Posted by sebackman View Post
    The time where we could assemble our own DIY set of drivers and create a system that is as good (or better) as what is available on the market has passed with these new complex system designs.
    +1

    It can be very satisfying and rewarding to tackle a modern DIY project, but short of building an accurate clone, the likelihood of matching the performance of a modern JBL or other top flight system is unlikely without a lot of work, prototyping, and a bit of good luck. Even with the excellent test equipment we have available these days, most of us do not have the test facilities that Harman and the other big boys have.


    Quote Originally Posted by sebackman View Post
    Many people here (and elsewhere) have made wonderful DIY systems that no doubt produce excellent results but they have been experienced individuals from the start and have spent a lot of time to get it right.
    I have built my own system that I prefer over the M2, but I wouldn't pretend that it is a universally superior system. FWIW: It is also a more costly system than buying factory built M2s.



    Widget

  15. #75
    Member sebackman's Avatar
    Join Date
    Feb 2004
    Location
    Europe
    Posts
    562
    JeffW, with that I totally agree. With all of it.

    Spending a lot of money and time, I would definitely follow your suggested path and get the best current (available) driver my wallet can withstand. :-) -And that is no doubt 2216Nd and not to forget the 2216Nd-1, that also can be found.

    To Anti K, if a DIY construction/design is contemplated I still argue that, if subs are used, there are alternative configuration that may make sense to ears, room and wallet.

    Widget, your designs don't count! You and a handfull others do have access to parts and knowledge most of us can dream about. No wonder your TAD's can give the M2 some stiff competition. That damn near cheating. ;-)


    Kind regards
    //Rob
    The solution to the problem changes the problem.
    -And always remember that all of your equipment was made by the lowest bidder

Thread Information

Users Browsing this Thread

There are currently 2 users browsing this thread. (0 members and 2 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •