Announcement

Collapse
No announcement yet.

Need help understanding passive crossovers power distribution ratios

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • #46
    Here's a picture that shows baffle step, and the correction for it. This is the same speaker that I posted previously. The step is the rise in spl from 300hz to 1k. You don't have to remove all of it. It sounds slightly different depending on how much you adjust it.

    Comment


    • #47
      Originally posted by STIchris722 View Post

      I see. Is that why some people talk about the rounding or shaping of the baffle face?
      The rounding is to smooth out the baffle step curve. Otherwise you often have peaks and dips as well as the 6dB rise. Rounding edges will not eliminate baffle step, only smooth the curve somewhat.
      Francis

      Comment


      • #48
        Baffle-step is the 6dB shift around the freq. where the baffle width relates to sound either being directed forward (shorter wavelengths - higher freqs.) or wrapping around the box to the rear (lower bass freqs. - longer wavelengths).

        Diffraction is a different matter. It's caused by (generally) higher freqs. reacting to disturbances as the waves move out from the driver's edge out across the baffle. Kinda like a car hitting a pothole and then bouncing a bit (on bad shocks). Drivers mounted on a board that's then mounted "in-wall" won't show any baffle-step loss, but can still have diffraction artifacts, esp. when the drivers aren't flush mounted.

        Comment


        • #49
          Originally posted by Serpentus View Post
          You know how you hear about subwoofers being omnidirectional? That's because the low frequencies tend to wrap around the baffle. The wider the baffle, the lower the frequency that wraps around baffle as the baffle can reflect sound. So you're losing about half the bass under a defined frequency, unless you place the speakers on a wall or corner.

          The three options are either have a naturally db louder woofer and cross at baffle step, lower the frequency above the baffle step, or a combination of the two e.g. 3 db hot woofer and -3 db above the baffle step frequency.
          When he says the lows "wrap around the baffle" what that means is that effectively the lows are radiating into a larger space than the highs and mids are. They don't have any extra energy to do so, so the effect is that the lows seem to be less prominent (compared to the upper ranges) unless that is compensated for by BSC, which raises the low end level up.

          Comment


          • #50
            Yes, exactly.

            Comment


            • #51
              Originally posted by Chris Roemer View Post
              Baffle-step is the 6dB shift around the freq. where the baffle width relates to sound either being directed forward (shorter wavelengths - higher freqs.) or wrapping around the box to the rear (lower bass freqs. - longer wavelengths).

              Diffraction is a different matter. It's caused by (generally) higher freqs. reacting to disturbances as the waves move out from the driver's edge out across the baffle. Kinda like a car hitting a pothole and then bouncing a bit (on bad shocks). Drivers mounted on a board that's then mounted "in-wall" won't show any baffle-step loss, but can still have diffraction artifacts, esp. when the drivers aren't flush mounted.
              When explained in the example of wall mounted speakers, everything clicked for me. It is really interesting that software doesn't tell the full story until the speakers are built, placed in a room, and then measured. I would have never guessed this 'phenomenon' existed.

              So when it comes to building a passive x-over, you really need to trial the build and compensate as needed? Am I correct here?
              "I don't know everything and do not claim to. I continue to learn and that is what makes me human."

              Comment


              • #52
                My sims don't give me accurate x-overs. Most likely due to small details. However, I can get good results as long as I can measure the responses. Even then, a dB here, and a dB there make a difference, and deciding which you like the best is sometimes a challenge. I can do this without sims! Usually do. For 3-ways, you need to really be willing to tweak things, or live with less than your best efforts. This process is simply fun, but can eat up some time. A hobby needs to waste some time, and distract you from day to day problems.

                Comment

                Working...
                X