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shots fired across the bow! (engineers vs 'the hifi people')

Discussion in 'audio' started by Jonathan, Jan 4, 2019.

  1. Purité Audio

    Purité Audio Trade: Purite Audio

    Sorry Toto, interrupted, I was just wondering where else they might go, where they are they do have a more or less symmetrical background and I presume the Tannoys are designed to be placed close to a wall.
    Keith
     
  2. ToTo Man

    ToTo Man the band not the dog

    Everything is a compromise but I do like the layout as it is at the moment. GIK's standard advice is to locate the speakers on the shortest wall as this reduces the severity of the peaks and nulls and moves the listening position further away from the rear wall. Most of their clients however have nearfield monitoring setups for mixing/mastering, not playback setups for pleasure, and when I ran the Room Simulator, because my room length and room width is very similar (4.14m x 3.78m), there was very little difference in the smoothness of the low frequencies by locating the speakers on the short wall vs the long wall. Locating the speakers on the short wall would also place the speakers closer to the side walls, meaning stronger first reflections, and the bay window would become a first reflection hotspot.

    The Tannoy Edinburgh cabinet features a distributed port system which apparently gives superior transient response at the tuning frequency than a conventional reflex design. You've probably seen it already, but I posted a photo of my room on the 2019 System pics thread. The gothic-style slots on the cabinets are the distributed ports.

    When both speakers are playing, the difference in the bass response between the left and right speakers isn't audible to my ears. Perhaps someone with a superior sense of directivity at lower frequencies would be able to hear it, but I can't, so I'm not losing sleep over it. I'm just curious about the cause of it, i.e. how much of it is due to the asymmetry of the rear wall (behind the listening seat) and how much of it is due to losses through the door on the right wall.
     
  3. Perart1

    Perart1 pfm Member

    I think that this thread sums up how pointless the debate is.
     
  4. DimitryZ

    DimitryZ pfm Member

    I have been seeing the title to this thread on a small screen and I though it said shots were fired across the bowl!
     
    Jonathan likes this.
  5. suzywong

    suzywong The Man who had no Naim

    That’ll be on February 3rd!

    I think that “shots across the bowel” would be more appropriate........
     
    Jonathan and TimF like this.
  6. Barrymagrec

    Barrymagrec pfm Member

    That was the only reason I looked at this thread.
     
  7. Barrymagrec

    Barrymagrec pfm Member

    I don`t know what goes on these days but forty or so year ago a fair bit of work was done by building 1/8th scale models of large proposed buildings (concert halls for instance) and making recordings of various sounds in them at 60ips then playing back the result at 7.5 ips to simulate the effect in a real size building.

    That was the basic idea, obviously there was a bit more to it than that.
     
  8. hammeredklavier

    hammeredklavier owner of two very cheap hi-fis

    Yes and no. If Weiner is right then pretty much all debate about the 'sound' of hi-fi electronics is consigned to the scrap heap once and for all because it's demonstrable that it does sound the same (with usual caveats about not clipping etc).

    If he's wrong then I would say on the basis of the past 30 years' experience, such difference as there may be is very small and irrelevant musically.
     
    booja30 likes this.
  9. Jonathan

    Jonathan pfm Member

    prolly at least as accurate as any digital models now -actual behaviour of materials notwithstanding
     
  10. h.g.

    h.g. pfm Member

    Not really. There are and always have been a wide range of problems with scale models for acoustic purposes which a brief google will reveal. Competently used simple and quick geometrical acoustics models are more reliable these days even with less than satisfactory diffusion, scattering and such. More sophisticated but computationally expensive approaches that largely remove these shortcomings are progressively being used more as computing becomes faster and cheaper.
     
  11. Jonathan

    Jonathan pfm Member

    i'm wasn't at ALL trying to suggest scale models weren't silly (since they didnt' mimic materials properly - you can't do stone with a balsa wood model!) but probably no worse than digital where most models are ill conceived at best ...
     
  12. AndyU

    AndyU pfm Member

    What makes you say most digital models are ill conceived?
     
  13. h.g.

    h.g. pfm Member

    Scale models were, and still are in a limited way, a method to obtain a range of useful information about the acoustics of buildings. Not all information but a useful amount. They have been largely replaced by geometric acoustic computer models which in turn are starting to be replaced by methods which more accurately represent sound propagation though often only for the low frequencies. The changes are driven by the ever reducing costs of computation compared with the high and largely static costs of experimentation.
     
  14. Jonathan

    Jonathan pfm Member

    because they ARE!! believe me it's mostly folly ... of course you can go in and tweak material parameters and keep running the numbers until you get the results you want but that's essentially the result ... you're 'gaming' the system in order to get a desired result in most cases. I don't think the incidence of 'computer optimised' models of concert halls requiring a complete re-fit has minimised WHATSOEVER during the digital age compared with 'before' ... some things are just too complex to model. To my mind the problem is the way the actual physics is modeled ... we simply don't understand enough about what energy does in a 'live' room - we only understand some very basic phenomena still ... but hey - whatever gets you on the road i guess - it's a problem MUCH like amplifier design i suppose. The proof is in the listening - and the tweaking - and then listening again ... ad continuum
     
  15. h.g.

    h.g. pfm Member

    Can you tell what it is about the physics of rooms and halls that is too complex to model or is that unknown? If unknown is that unknown for you or unknown for everybody?

    If the predictions and measurements of the transfer function of an amplifier is linear to within the amount that can be identified by listening alone in a blind test would it still need tweaking and listening, tweaking and listening,...?
     
  16. davidsrsb

    davidsrsb pfm Member

    A lack of information about frequency vs absorption of construction and furnishing materials used for a start
     
  17. AndyU

    AndyU pfm Member

    Happy to believe you if you are a recognised authority in concert hall design, or have designed concert halls that have met with critical acclaim. Otherwise I remain sceptical that computer models are unhelpful.
     
    Cav likes this.
  18. h.g.

    h.g. pfm Member

    Why do you think this information is missing? If it were missing what would prevent it being measured and/or simulated with a computer?
     
  19. davidsrsb

    davidsrsb pfm Member

    You would have to place a sample in a test chamber and measure the reflected signal against frequency. This information is rarely done and when it has been, not published.
     
  20. sq225917

    sq225917 situation engineer

    Last edited: Jan 13, 2019

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