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Chris A

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    Arlington, Texas, USA

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  1. I use the term "waveguide" mostly because so many audiophiles here have trouble with the term "horn". I think that Bjorn's book helps to bridge some of that divide: https://hornspeakersystems.info/ https://www.parts-express.com/high-quality-horn-loudspeaker-systems--500-032 It's a good update on Beranek's "Acoustics" and Olson's "Acoustical Engineering" texts. The theory portion of the above book (i.e., the last ~40% of the book) looks good and is useful in terms of theoretical considerations and current analysis developments, but is a little thin in
  2. The last major category of loudspeaker acoustic requirements (as opposed to non-acoustic requirements) is directivity: The biggest issues that I see with directivity requirements/capabilities can be grouped under the three major subheadings above: directivity at higher frequencies (generally above 1-2 kHz, but this can extend down to ~500 Hz), and low frequency directivity (below the higher frequency directivity regime). Additionally, there are issues with coverage: 90 degrees horizontally (-6 dB) above the room's Schroeder frequency--typically taken to be
  3. I'm really not sure what your needs are, but I'm pretty sure that what you intend and what I'm currently working on are not coincident. I would recommend that you start a separate thread on the exact subject (which looks like random measurements). (As the OP) this thread is clearly focused on something other than your expectations. Chris
  4. Expanding the distortion hierarchy... (We'll get to directivity next after the distortion hierarchy is discussed.) Here, the story begins to get a little more interesting-in my view. Notice that I've "double dipped" on phase/impulse distortion here vs. the transfer function hierarchy, but perhaps choosing one place or the other would be the next step in finalizing the rolled-up hierarchy. The light blue background indicates that these performance capabilities are correctable using signal processing. There have been a few attempts to using DSP to correct harmonic and
  5. Note that I own no stock in Danley and have no other financial interests with them, nor do I own any stock in any other loudspeaker company or have any financial interests in any of them. I sell no products and charge no one for my services. Chris
  6. That's fine with the Dutch & Dutch approach, but note that the technique that is used is diffraction--the same approach used by line arrays (see the Danley paper on this subject). To be honest, line arrays only work well if you're sitting in a certain place in the audience, and they really suck if you're not sitting in the right areas... Danley is systematically replacing line array technologies and gaining significant market share in that market (i.e., when there was a fixed installation PA market before SARS-CoV-II hit the scene). There's a reason why they are.
  7. Moving on to the next level of aggregation of requirements/characteristics, expanding on the transfer function: The above next-level hierarchy is from the same two-year-old file I created to notionally talk about the type of transfer function-related characteristics (i.e., SPL and phase response...and group delay--the first derivative of phase). Here you will begin to see some of the lower level characteristics that affect acoustic performance. It pulls in the box stiffness/resonances and "baffle step" (otherwise known as "flat-horn gain") that a gentleman inquired ab
  8. The one in the middle in the picture above is my prototype: it's a full-range multiple entry horn (MEH) with 90x60 degree coverage from 100-20000 Hz, and SPL response is 18-20000 Hz, and has phase and group delay response that beats most non-FIR-filtered studio monitors (i.e., the one in the above picture doesn't use FIR filtering--just IIR filters). It was created from a midbass module from a behind-the-screen cinema setup, reusing only the horn and box. There have been a few others of this configuration built by others based on this design. I'll talk more about my designs (if
  9. Patience, grasshopper. All will be revealed in its time... 🙏 Continuing on, now taking up the more well-known/advertised design capabilities of transfer function response and time-based response (impulse, decays, etc.), these capabilities are more easily shown in a hierarchical format... I created this notional loudspeaker capabilities/defects hierarchy a couple of years ago for talking purposes in another thread, and some of the naming and placement of the quantities would likely change a bit, but for the purposes of this thread it's good enough for now,
  10. Rigid box--no flexing is the goal (same for the waveguides). This of course must be traded against weight and material cost, but in general, the trend over time has been toward stiffer boxes. Remember the goal of a loudspeaker discussed above: it's not a "maker of music" but rather a "reproducer". Chris
  11. No worries. I hope that you will find something here that you can use. However, it might take a little while to fully develop the topic, so patience might be a good characteristic to have extra helpings of here... 😉 Some of this is probably going to be a bit subtle for those not into loudspeaker engineering. Chris
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