1. Things you need to know about the new ‘Conversations’ PM system:

    a) DO NOT REPLY TO THE NOTIFICATION EMAIL! I get them, not the intended recipient. I get a lot of them and I do not want them! It is just a notification, log into the site and reply from there.

    b) To delete old conversations use the ‘Leave conversation’ option. This is just delete by another name.
    Dismiss Notice

3rd edition of Floyd E. Toole's "Sound Reproduction"

Discussion in 'audio' started by Julf, Jan 10, 2018.

  1. cooky1257

    cooky1257 pfm Member

    The happy compromise corresponds to where the horizontal dispersion of the horn meets(matches) that of the Bass/mid.
     
  2. Yank

    Yank Bulbous Also Tapered

    There's no such thing as a "bad" crossover frequency, as long as it's well-executed.
     
  3. S-Man

    S-Man Kinkless Tetrode Admirer

    Fair cop Cooky. I made 5 out of 2 + 2. Apologies.
     
    cooky1257 likes this.
  4. S-Man

    S-Man Kinkless Tetrode Admirer

    As I understand it even an ideal crossover (where the slopes match perfectly) will have time domain anomalies once the order of the slopes is >1.
    Whether or not these time domain imperfections are audible is open to debate. I believe they may be at LF and therefore IMO the lower the XO frequency the higher the possibility is is "bad".
    Actually I tried argue that it doesn't matter with some very experienced speaker designers and I lost the argument.
     
  5. darrenyeats

    darrenyeats pfm Member

    Crossovers are a "necessary evil" - if we could have a driver that covered 20Hz-20kHz without distortion or narrowing we'd never voluntarily add a crossover! Since voice, which we are most sensitive to, is predominantly 300-4000Hz I think it's desirable for one driver to cover that range. It's difficult for a driver to perform well over even just a decade, ISTM a slightly smaller range sitting inside the above range is one reasonable approach.
     
    Last edited: Jan 13, 2018
  6. tuga

    tuga pfm Member

    Yes, I believe that the M2 design objectives were lower cost and loudness, not performance.

    By the way, my opinion is not solely based in those "chinese knock-offs" but also in extensive listening of the 2402 Pioneers of a (then) local audiophile. Even when used with the optional tweeter.
     
  7. tuga

    tuga pfm Member


    300Hz would be at the middle of the fundamentals range for the majority but 800Hz is still at the top of the range for many.
    And you mustn't forget that several instuments produce harmonics that are as high in level as the fundamental note:

    [​IMG]


    This is a spectrogram from a R.Strauss orchestral work:

    [​IMG]


    I think that for acoustic instruments it would be best to have a single driver cover the lower- and core-midrange (~150-250Hz to ~2KHz).
    This is for direct radiation or mixed speakers because multi-channel horns driven with band-passed SET amplification have specific requirements.
    The midrange in SP9/1s I once had was crossed too high at 600Hz.

    Idealy for a large full range direct radiation speaker the size of the M2 I think that one should have different channels for sub-bass, bass, midrange and treble.
    And the M2's horn is probably acting more as a waveguide, with the compression driver working as a direct radiator.
    Yes the on- and off-axis response curves are impressive but I suspect that they'll strugle with complex music.

    P.S.: and no reflex or other low frequency crutches allowed
     
  8. S-Man

    S-Man Kinkless Tetrode Admirer

    Why?
    And what do you mean by "struggle"
     
  9. cooky1257

    cooky1257 pfm Member

    I dont need to, the wisdom of your post is there for all to see. but just for you. The M2-JBL's new flagship monitor, fully DSP/active, the culmination of new transducer design(bass and HF), a completely new throatless waveguide, the extensive R&D and you say the design objective wasn't 'performance'.
     
  10. tuga

    tuga pfm Member

    I have tried to explain that.
    It's a 2-way speaker with a 38cm woofer in a very large box with bass reflex when it should be at least a ported 3-way.
    The shortcomings are inherent to the topology.
     
  11. darrenyeats

    darrenyeats pfm Member

    When it comes to voice your chart gives a very different impression to for example http://www.bnoack.com/index.html?http&&&www.bnoack.com/audio/speech-level.html.
     
    tuga likes this.
  12. S-Man

    S-Man Kinkless Tetrode Admirer

    Bass reflex is the same as ported. Isn't it?

    Other than that I agree with you, in principle. OTOH the M2 seems to have overcome the problems of beaming inherent in crossing over a large driver with a small one - the measurements are hard to argue with! (Although we don't get to see vertical off-axis performance, so the jury is still out if they really have overcome the problems).
     
  13. tuga

    tuga pfm Member

    Yes, let's believe the marketing bla-bla instead.
    Very "insightful" of you, unlike my "stupid".

    It would be interesting to compare the M2 with the Revel Salon2.
     
  14. tuga

    tuga pfm Member

    I agree, wrong wording. There are several ways to "support" bass but in my opinion they all produce unwanted artifacts and affect transient response in a negative way.

    Toole & Co. are obviously big in the power response thing but wider-band use of a driver produces intermodulation distortion and requires a heavier hand in the crossover to flatten response.
     
  15. cooky1257

    cooky1257 pfm Member

    EQ for M2. Horn eq goes with the territory but the LF looks pretty light rather than heavy....design/use a driver that's good for its intended pass band and forum lore goes away.
    I come from the 'there's more than one way to skin a cat' school of thinking regarding speaker design and you wont catch me slagging 3/4/5 way designs, ATC'100A for example can be superb, Gale 401's are great too. All represent compromises.

    [​IMG]

    [​IMG]
     
  16. cooky1257

    cooky1257 pfm Member

    The Revel Salon2 is an excellent Harman research influenced loudspeaker that (although a very small sample) subjectively came out on top against the M2 in a recent bake off scenario..different power amps may well have produced a different result who knows.

    Oh please substantiate your not for performance claim.
     
  17. cooky1257

    cooky1257 pfm Member

    FR & DI plots incl vertical, pattern control in action, oh and take note of the word 'performance'.

    [​IMG]
     
  18. tuga

    tuga pfm Member

    The right wording for that caption should be:

    These detailed frequency response measurements of the M2 illustrate the system's exceptional performance in that one particular parameter.

    The difference is substantial.
     
  19. tuga

    tuga pfm Member

    See previous posts.

    Frequency response is but a single objective parameter of the multiple aspects that characterise speaker performance.
     
  20. tuga

    tuga pfm Member

    I disagree.
    Even with a steep filter you are mixing the sound from two different transducers. This disrupts the continuity of tone and timbre of instruments producing continuous or legato (as opposed to staccato) sound like a bowed cello or a violin, or human voice.

    The audibility of a well executed transition may be questioned but the theoretical advantage of not having two drivers cross at a crucial frequency is in my view undeniable. A single wide-band driver would be the best option if it weren't for the innumerous shortcomings.
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice