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Adjusting room sound using DSP (not damping)

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  • #31
    Re: "KRK Ergo" - inexpensive room correction that works?

    Hi Rob
    no it doesn't.
    I'm not sure what to say to you. All I can report is my (very positive) experiences.
    I understand the Lyngdorf/TacT is quite sophisticated in it's correction algorithms. Perhaps you might like to try one and report.
    Best Wishes
    Andrew

    Comment


    • #32
      Re: "KRK Ergo" - inexpensive room correction that works?

      I had my friend Ian over last night. He came over to hear what I had been raving about.

      We demo'd Glenn Gould's Goldberg Variations, Mahler's No 2 with Ivan Fisher and the BFO, A little Clare Martin and Diana Krall and a touch of LTJ Bukem for drum and bass.

      It was very disappointing at first - tons of mid resonance and flabby bass - highs were far from what I had heard previously. In fact the whole system sounded very average to me. My "Eureka" moment felt like a fraud.

      The effect of battery vs SMPS on the KRK was non existent.

      "Oh dear" thought I "what little credibility I retain has just departed".

      Well lots of shaking of my head, muttering about apartment power supply vagaries, enumerable set up and cable changes and lots of "f*#king hi fi" later Ian suggested another room cal. He asked - had I moved the speakers? yes by about 14 cm and toed them out abit. Plus sat them on Auralex Gramma Platforms. Surely those minute changes wouldn't have made much difference.

      Room cal was run -(4 readings 94% room knowledge) and again a reported 4 on the room correction scale (whatever that means - not sure if it is % or out of 10). For reference Ian's 7 with a sub.

      The result?

      We both instantly heard considerable improvement - the bass was tidied up a great deal and the mids, while they still had the resonance, had much less. Ian, who being a classical pianist has a much better ear than me for tone, postulated it was around the 400-500Hz mark (which is quite a high pitch "A" is usually 440Hz) ie on the limit of what the Ergo can cope with. The highs were the biggest change - being clean and clear like someone had lifted a veil. "Aha - that is what I heard when I raved about the KRK" says I - some semblance of credibility returning coupled with a great sense of relief.

      So the moral of the story - if you move your speakers be prepared to re-cal. Second moral - it is not a substitute for all room tx but certainly doesn't hurt. Moreover I wonder about the accuracy of the room cal - it seems to vary depending on where you take your readings.

      We were running late so we didn't get a chance to a/b battery vs smps for the dac. Ian took his home and will report if there is any benefit in his system or not.

      I was beginning to think that what I may have been hearing was the properly cal room and not the dac being swapped from smps to battery. Later I did some a/b's and found little difference with the battery to smps - perhaps a slightly better delineation and imaging but there wasn't much in it.

      This hobby can be frustrating sometimes he he.

      Audio Nervosa began to set in so having a period of just listening to the music and forgetting my system.

      Cheers
      Andrew

      Comment


      • #33
        Re: "KRK Ergo" - inexpensive room correction that works?

        Originally posted by tricka View Post
        ... So the moral of the story - if you move your speakers be prepared to re-cal. Second moral - it is not a substitute for all room tx but certainly doesn't hurt. Moreover I wonder about the accuracy of the room cal - it seems to vary depending on where you take your readings....
        Neither of these should be a surprise. Move the speakers, move the microphone or move your head will generate a soundfield that is sufficiently different that the correction appropriate to another position of speakers, microphone or head will be completely inappropriate. Could make the resulting sound (as you've found) worse, not better.

        You have hit upon the fundamental reason that room correction has not really caught-on; it may work well if everything is carefully optimised but it can really only work properly for one solitary listener with his head in a vice sitting still in the sweet spot where presumably the reference microphone took it's measurements.

        In my view, it's always proved better to invest in room treatment and to increase the amount of material absorption which would give a balanced sonic experience to a group of listeners spread throughout he room not just one single enthusiast at the hot-spot. I note that professional studios of my experience never use room correction - they damp the room with wall lagging.
        Alan A. Shaw
        Designer, owner
        Harbeth Audio UK

        Comment


        • #34
          Re: "KRK Ergo" - inexpensive room correction that works?

          Alan, that is also my experience.

          I think EQ can be of great use but should be used sparingly once the room has been optimised as you outline above.

          Often this can be achieved with subtle correction as offered via amplifier tone controls but if using a more complex solution such as graphic or parametric EQ, take the predicted correction curve provided as a guide only. Using these devices can be an interesting and useful window onto what the room is doing (mainly at LF) but some intelligent interpretation of the results is required.

          A practical example may help:

          I once installed a Pro auto eq device into my system and let it auto calibrate for best in-room response. The result was frightening because it put 15db of boost in at 20kHz and 12db down at 30Hz. Such levels of EQ can be catastrophic in practice. The system couldn't differentiate between room issues and speaker limitations so it tried compensating for the tweeter's rapid fall off above 18kHz and the lack of LF extension below the speaker's natural roll-off. An extreme example perhaps but it highlights the need to apply some logic, common sense and real world experience when using these powerful devices.

          Comment


          • #35
            Re: "KRK Ergo" - inexpensive room correction that works?

            Originally posted by RobHolt View Post
            ... The [correction] system couldn't differentiate between room issues and speaker limitations ...
            Again, this is exactly what I'd expect if you let the correction system 'do its own thinking' and you have no means of interpreting or overriding whatever correction it intends to apply.

            The human ear is really remarkably good at hearing through room problems of too much or too little energy (humps and bumps in the frequency response) in-room and can permit a decent sound to be achieved in most rooms. However, the ears temporal abilities can't be fooled so easily - that's to say, those sounds that linger long after the note has ceased, due to the room especially in the mid and upper frequencies. They're really irritating. We'd call those frequencies ringy because of their time domain effects ringing-on. It's relatively straightforward to correct frequency response lumps and bumps (by applying a graphic equaliser in software or hardware) but I'm not so sure how effectively hard, ringy rooms (or speakers) can be negated in software.

            As you say, it really is far, far better to solve mechanical problems mechanically (rooms, speakers, turntables, microphones etc.) rather than by layering electronic technical wizardry (such as DSP) on top of a fundamentally flawed mechanical design. Once the basic mechanics (such as room damping) really have been taken as far as possible then's a good time to consider electronic solutions for the last few percent of perfection.
            Alan A. Shaw
            Designer, owner
            Harbeth Audio UK

            Comment


            • #36
              Re: "KRK Ergo" - inexpensive room correction that works?

              it may work well if everything is carefully optimized but it can really only work properly for one solitary listener with his head in a vice sitting still in the sweet spot where presumably the reference microphone took it's measurements.
              I agree with you both and so does the manufacturer - it was never a substitute for proper room treatments and may be entirely unnecc if those are suitably applied.

              FYI the Ergo has "Focus" and "Global" settings. The Focus gives you a 3 ft cube around your primary listening spot and the Global is the best interpretation of the correction for out of Focus position. I run it in Global 90% of the time to very good effect.

              The ergo also takes many readings not just one to build a "3D Image" of your room. How it does this with math I do not know.

              It certainly doesn't change the character of the speakers to turn them into 2 inch wide sweet spot electrostatic panels or some such.

              I think also that a distinction needs be drawn between pro and domestic environs. The former has no restrictions on treatments while the latter frequently will - certainly my wife wasn't enamored with the foam I had up. And I might say that I prefer the 'life" I have in the music now the foam is down. Every recording room I have been in which measured flat sounded accurate but boring.

              Anyway it's an interesting low cost product that has helped in my domestic listening area which I have had fun playing around with. Not suggesting it is the next coming or anything like that.

              Comment


              • #37
                Re: "KRK Ergo" - inexpensive room correction that works?

                Originally posted by tricka View Post
                ... it was never a substitute for proper room treatments ... certainly my wife wasn't enamoured with the foam I had up ...
                That I understand! Damping the reflective surfaces in the room (floor, ceiling, walls) is a very contentious issue at home (and even in modern, all-glass see-through studios) because more damping always means more absorptive material must be applied to those surfaces. And that in turn means the room will be darker (absorptive materials tend to absorb light too), more difficult to keep clean (absorptive materials tend to have a furry surface which attracts and holds dust particles) .... and absorbers do look distracting in the normal home. So for all those reasons, I agree that an electronic solution is obviously very appealing - if it can be made to work.
                Alan A. Shaw
                Designer, owner
                Harbeth Audio UK

                Comment


                • #38
                  Re: "KRK Ergo" - inexpensive room correction that works?

                  I can report a positive influence in my listening space with this wee device.
                  With respect I don't think you can really comment beyond conjecture unless you have tried one out yourself.
                  Cheers
                  Andrew

                  Comment


                  • #39
                    Lyngdorf room correction + C7ES3 = eclipses any other upgrade

                    A belated contribution--I'm using a Lyngdorf TDAI 2200 with a pair of Compact 7-3s and the results are wonderful. I also use a McIntosh MEN 220 (which is the Lyngdorf system) in another room with a pair of McIntosh XR-200s, which is also wonderful in a slightly different way from the Harbeth setup.

                    My experience with the Lyngdorf products makes me feel that after 48 years of listening to recorded music, I can't imagine doing it without such correction. The differences completely eclipse issues like cabling, power amp differences, etc.

                    Comment


                    • #40
                      TDAI 2200 room correction?

                      Hi Wally, I have a piar of C7ES3's and I'm looking at the TDAI 2200 and other dsp room correction options. Could you describe your room and setup? What amp did you use before the TDAI and what would you say the differences are with and without using room perfect?

                      Thanks

                      Mike

                      Comment


                      • #41
                        Dpa

                        hi,

                        yes, i use the lyngdorf DPA-1 preamp (including room perfect) feeding an electrocomapniet AW250-R amp and my M40.1. for me the room correction is simply the BEST tuning device in hifi-business. you will no longer think about cables or other negligibilities. in my (somewhat difficult) room the lyngdorf allows for 31 Hz (-2dB) without any frequency artifacts.
                        given the very cheap prices for lyngdorf stuff it is simply a must for any critical room.
                        btw: i just saw that mc intosh now released a room equalizer with lyngdorf technology (costing double the price as lyngdorf here in germany)...

                        the only "problem" with the lyngdorf i can think of is: if you are a hardcore analogue user you might (more psycologically) have a problem with the d/a conversion of analogue signals.

                        best,
                        delgesu
                        Harbeth M40.1-Naim NAC52-Supercap-NAP 135-CDS2-XPS

                        Comment


                        • #42
                          TACT room correction & how to interpret graphs

                          I have just purchased a second hand Tact 2.0 RCS and am about to start on trying to use this in my room with my Harbeth Compact II units. I appreciate what Alan says about the rigour when using any RCS set up and that it is based on a single postion but looking at the TAct at least this does not need to be the case. There is a facility to take average measurement for the main listening position but you can also combine doing measurements from a number of positions then combing them and getting a filter option that optimises the sound averaged for all the positions. Now of course this will be a compromise but as I view using this as something to help with room problems then it should be effective.

                          There is also the option on the Tact to set up to 20 different filter / adjustment memory settings so you could have one set up for just solo listening one for when there are two sat next to each other and another for when there are a number of people listening (probably not that critically) . each could then be used as needed.
                          I am not expecting the Tact to solve all my problems nothing ever does but if I can get it to let the Harbeths just get on with their job then it will be worth it.

                          If anyone knows of any primer (or even simpler) articles on how to read a signal frequency graph then add some links as I have no problem in admitting I am not that knowledgeable in this area .

                          Comment


                          • #43
                            Fiddling with inter-channel phase ....

                            A newly joined member says that he has had good results with this DSP room correction system here: http://www.audiovero.de/en/

                            It seems that they have a demo version?

                            One thing I have to report about a DSP system I've been experimenting with: the system calculates and introduces an inter-channel time delay of a few thousandths of a second. This significantly changes the quality of voice, 'cleaning it up' etc. etc.. However, if the DPS remains in circuit but this delay is overwritten and set to zero, voice returns to its normal characteristic, and even though the overall speaker/room response remains a flat line (or whatever line you program).

                            The worrying thing is that the magic effect and definitely audible change is seemingly related to nothing more than the inter-channel phase difference, the ear being astonishingly tolerant of all the normal room's usual sonic lumps and bumps. Was I disappointed ....
                            Alan A. Shaw
                            Designer, owner
                            Harbeth Audio UK

                            Comment


                            • #44
                              It really works - free trial

                              Originally posted by A.S. View Post
                              A newly joined member says that he has had good results with this DSP room correction system here: http://www.audiovero.de/en/

                              It seems that they have a demo version?

                              One thing I have to report about a DSP system I've been experimenting with: the system calculates and introduces an inter-channel time delay of a few thousandths of a second. This significantly changes the quality of voice, 'cleaning it up' etc. etc.. However, if the DPS remains in circuit but this delay is overwritten and set to zero, voice returns to its normal characteristic, and even though the overall speaker/room response remains a flat line (or whatever line you program).

                              The worrying thing is that the magic effect and definitely audible change is seemingly related to nothing more than the inter-channel phase difference, the ear being astonishingly tolerant of all the normal room's usual sonic lumps and bumps. Was I disappointed ....
                              Alan,

                              I've known Uli Brüggemann for a number of years and his software is not a sham at all.

                              The easiest way to get an impression is to measure your system in room with the SW you can download for free. Then you send him a couple of pieces of music of your own own choice and he will convolve them for you and them back. You can then compare as you like.

                              I understand your careful approach to this issue, but beyond the reality that you must re-measure when you make changes in your room I can only say that I find the results I have heard with acourate very impressive.

                              I have heard acourate applied in a room that was totally unacceptable with lots of hard surfaces and I would not have thought that possible.

                              I have no financial or other interests in these products except as an enthusiast of good sound.

                              Greetings from Brussels

                              Robert

                              Comment


                              • #45
                                Audiolense DSP system

                                Alan,

                                I had been used Harbeth M40 for about two years and found its bass was too much in my 20" x 16" listening environment. Eventually, I solved the bass problem by using another room correction software called Audiolense which is very similar to Acourate.
                                The sound is still Harbeth sound but the bass problem disappeared and did not bother me anymore. Moreover, the sound is really transparent and has no electronic signature at all.
                                It also has time domain correction which makes the sound image very stable and well defined.

                                I am very happy with the result.

                                Link: http://www.juicehifi.com/index.html

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