Can DSP fill in woofer dips?

July 25, 2022
 by Paul McGowan

16 comments on “Can DSP fill in woofer dips?”

  1. Having raved recently about near-field subs, Paul, the question arises if these measured peaks in the bass region need a similar damping too? Having the walls reflecting the bass sound wave now far away (and the floor quite close (down fire) and music being characterized by more or less steep transients (even bass drums) our ears might ignore the delayed waves??? Again a situation where „simplistic“ measurements might not help a lot!?

    1. ps,
      With regard to today’s ‘Paul’s Posts’…I approach home-audio from a more ‘practical’ view-point, probably brought about by my years in home-audio retail, whereas you tend to come more from the theoretical side of home-audio…well, more theoretical than me anyway.
      I just wanted to clear that up ✌ 😉

      1. You can be sure, FR, that my approach to stereo is based on two solid columns: theory & practice. I have a degree in gas dynamics & fluid mechanics and a long term experience in wind tunnel research. I am also aware of the omnipresent problem of cognitive bias especially authority bias. I have never met a retailer or sales guy who didn’t try to “convince/persuade” customers using the tool of “authority bias”; however nobody ever could explain why a specific design or technology should yield in a better sound! 🙂 And I am pretty sure you are most familiar with the fact that authority bias is a most powerful marketing tool. I trust my own ears and always ask for feedback from my audiophile buddies who are often shocked by the effects and sound-improvements of my tweaks often developed from theoretical facts! 🙂

          1. Don’t please pigeonhole me as an authority unless you have made clear which type of authority you mean: rational, irrational, epistemic, deontic, ….! I would never ever claim being an authority. And in fact I have never met a person in my life I would have accepted as an authority. However shouldn’t everybody who predicate something also should be able to give a substantial proof based on proven and reproducible facts? 🙂

            1. Firstly, I’m pleased that we can joust humorously 😀
              Secondly, my comments, if I’m being serious, are from my own personal experience in home-audio & there are no expectations from me that others must agree with my experiences or my views.
              Thirdly, I have never pressed anyone to buy anything that they didn’t want to buy during my years of selling in Hi-Fi retail & therefore I reject your assertion that I used the tool of “authority bias” to persuade any prospective customer to buy anything that they did not agree suited their home-audio needs.
              My mantra & my advice to prospective customers has always been, “Trust your ears”.

              Squirrels & Rats should be able to live together harmoniously 😉

              1. Did I really impute to you having practiced selling methods based on authority bias tricks or didn’t I rather assume that you know how these methods are used by many resellers and sales guys but also by reviewers? 😉 I have attended several audio demos performed by famous reviewers from renowned audio magazines and they all operated using proven methods of “suggestion” putting into the listener’s mind what he will hear and additionally perceive in the next demo step. And by the way: rat are very social and caring animals. 🙂

                1. Yes, I have encountered some really arrogant so & so’s in the Hi-Fi trade over the decades who took great pride in telling their customers exactly what they should buy.
                  I’ve been away from it for 12 years now.
                  Making your hobby your business can often backfire.
                  These days, for me, life’s a breeze ✌

                  The only time that a salesman should assist in making a decision for the customer is when (s)he is asked by said customer to do so.

  2. My 14′ x 16′ listening room has standing wave issues. My system features open baffle cabs with 15″ Acoustic Elegance woofers. Fortunately, at my listening position, there are no major dips and my DEQX HDP4 flattened out the peaks. Low frequencies sound great in my small almost-square room.

  3. I remember many years ago I purchased (2) 12″ RH Labs subs for about $ 800.00 apiece. I asked the salesman why I never heard of the brand before He replied the company did not advertise to save money and build a better product. I always wanted a Veledyne servo but couldn’t afford them. I Was never happy with the sound of the RH labs and ended up selling them at a loss. I Learned a valuable lesson I guess in sales tricks. Sub sounded rubbery and disappointing. Also I don’t believe a crossover was provided. I later purchased one but only 12 db down did not reduce enough midrange. 3rd or 4th octave would be a better option. Also I was sitting in a chair in the middle of the room with the subs to the left and right of my armrests. couldn’t understand why not much bass. Years later I discovered the middle of the room is a Null hence most of reason for being disappointed. ahhhh. If only I would have purchased Paul’s Audophile Guide but am sure it was not avalaible back then.

  4. If the dips at certain low frequencies are due to the speakers or subwoofers themselves and not the room you can fill it in through equalization. But you will be using extra amplifier power to do this. I have a bass equalizer and graphic equalizer with spectrum analyzers and room microphones so I can pinpoint the problem frequencies and fix it preferably without any equalization at all. I also have an analog device with Mic that shows me the frequencies.

      1. Yes I mean electronically reverse the phase at the point it’s canceling so it’s a peak that can be equalized down to flat and not a dip cancellation that cannot be equalized up no matter how much energy is used.

  5. Joe nice job. You were really paying attention and formulated an hypothesis to boot!
    Okay Paul, let’s let the kids do this. They’ll figure it out.

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