Kvalsvoll

Members
  • Content count

    384
  • Joined

  • Last visited

  • Days Won

    19

Everything posted by Kvalsvoll

  1. I guess we are up for a surprise here, because I have not watched it yet, just did the bass-eq with a nice ulf boost.
  2. Always a risc of blowing something when you develop and test new equipment. This scene is fine on the horns, you can see the cones moving, but you don't hear a thing, and nothing is overloaded. It is very possible that they did not know it was there, because the spectrum analyzers are set up to show from typically 20hz and up.
  3. I agree about the feeling-part for low freq - hearing is focused on the higher frequencies, so the lows knid of add power and weight to it all. Commercial subwoofers use to have limiters to avoid possible damage, because most people do not scan content with a spectrum analyzer before watching, actrually, most people do not know what spectrum analyzer is, and neither should they need to. The Amaze demo is great, but not for the bass, the "powerful bass" moment is only a distorted, rumbling mess. And if the system can not handle the lows on this one, something with heavy low content will be a disaster.
  4. I can start a new thread on this, the distortion experiment can also be included there. I will then explain how the experiments were done, the results make no sense without knowing the procedure and limitations.
  5. Subjectively, it is more feeling, because the higher harmonics mask the fundamental. The distortion test was only down to 80hz. I did a different test for detecting threshold of hearing, and found that you always hear the tone before you feel it, even well below 20hz. I tested down to 10hz. If there is interest in it, I can find the results and notes and post them here.
  6. When viewing the results plotted in a fr chart, it becomes obvious and simple - there is masking around the fundamental, and the rest is audible as if the distortion components played by their own, with no fundamental. A strange observation on thew 2h is that the phase of the harmonic affects perception, and it is possible to find combinations of level and phase that actually makes the tone seem more clean.
  7. Would it not be great if you could bring back the lost bass in you favourite movies? Well, perhaps you can. By applying equalization customized for each movie during playback, it is possible to dig out some of the low bass lost due to filtering and processing in the studio. Why Bass EQ How to Bass EQ How to recognize good candidates for Bass EQ and what to fix How to submit Movies with Bass EQ Movies improving with Bass EQ This is the list of movies that can be improved by applying Bass EQ: A Space Odyssey Alien Aliens Alien3 Avatar Avengers Avengers: Age of Ultron Battleship Bølgen (The Wave) Ender's Game Eyes Wide Shut Full Metal Jacket Godzilla Gravity Guardians of the Galaxy Iron Man Iron Man 2 Iron Man 3 Man of Steel Oblivion Pacific Rim Scott Pilgrim vs the World Shining Star Wars: The Force Awakens Super 8 The Matrix The Matrix Reloaded Thor Thor: The Dark World Transformers Transformers:Revenge of the Fallen Transformers:Dark of the Moon Transformers:Age of Extinction coming soon: Master & Commander BluRay Tron:Legacy Batman Begins The Dark Knight Fight Club Star Wars: The Phantom Menace Star Wars: Attack of the Clones Saving Private Ryan Wreck-It Ralph Top Gun Alien Resurrection The No Hope Movies Some movies can not be improved: The Hobbit: An Unexpected Journey Update sep 16 2014: Changed Bass EQ implementation and description method, updated movie entries. Update jan 11 2015: Filter parameters for early entries updated to match new MiniDSP implementation.
  8. The Room2 is a test and demo room, but it is also where I listen to music most. So I want to share with you what music I played in a short listening session this evening, music examples are something I always find very interesting and useful, so perhaps someone finds inspiration for new things to listen to. I suspect many of you have never heard about none of these. 1. Voices of Music - La Folia. The long 10 min one, with the dancers. The F2 speakers allow for a little louder master (-3dB) than you would experience in a live performance for this sort of music, but that makes the realism better, especially when the dancers stomp the scene floor - the recording is full-frequency-range, so you actually feel the scene floor moving. 2. Voices of Music - La Folia. A different version. 3. Flashbulb - Piety of Ashes. New release, only one track available as preview. Excellent, this is something quite different from the baroque ensembles. Master 0dB. 4. Flashbulb - Soundtrack To A Vacant Life, tracks 4, 5, 6. Excellent music, excellent production. This is electronic music, with a complex and detailed sound landscape. Bass is physical and tight. Master 0dB. 5. Jøkleba - Jøkleba! Nu jøk - Girl, Firefly. Jazz. Very dynamic recording, heavy and tight punch from the large drum, trumpet so present and rendered with such clarity you can see the fingerprints on the brass. Master +3dB. 6. Daniel Herskedal - The Roc - 07 The Afrit, and 08 There Are Three Things You Cannot Hide; Love, Smoke And A Man Riding On A Camel. Jazz. Herskedal experiments with his tuba and creates a musical journey. Again - bass is physical, and the drums has this realism you otherwise only get at a live concert. Master +3dB. 7. Hadouk Trio - Utopies, Shamanimal Live. Jazz. Here the V80 horns excel in rendering the deep, powerful bass tones. Master +3dB. 8. Jøkleba - Jøkleba! Nu jøk - 16 - Schopenhauer. One last jazz track. Master up to +6dB for a truly visceral experience on this relaxing masterpiece. The music can be found on Bandcamp and Tidal. Voices of Music on youtube unfortunately, make sure to get the best possible quality on the audio stream. Current equipment in Room2: F2 main speakers and 2x V80 compact horn bass-system.
  9. I have posted about the new Room2 in the bass punch threshold thread, and announced that I would start a thread on the building of this room. I plan to present a complete article describing what the acoustic improvements do for the sound, from start to finish, and I also have measurements form all stages of the build process. Here is how the room looked initially, after removing subwoofers and audiophile mains, and some furniture, including the table, which will be replaced: Preview of the process:
  10. Or, there may not be that much research done on this at all. If the subject has little interest outside audio/hifi - because audio research has always had a tendency to focus on technical properties that may not be very relevant, and less on hearing perception mechanisms. I did a test to find audibility limits for distortion not long ago. Look at these numbers. 440hz: 60dB 2h -34dB 2% 3h -50dB 0.32% 4h -50dB 0.32% 5h -53dB 0.22% 6h -50dB 0.32% 8h -58dB 0.13% 70dB 2h -34dB 2% 3h -50dB 0.32% 4h -54dB 0.2% 5h -65dB 0.056% 6h -64dB 0.063% 8h -72dB 0.025% 80dB 2h -34dB 2% 3h -34dB 2% 4h -43dB 0.71% 5h -65dB 0.056% 6h -72dB 0.025% 8h -76dB 0.016% This data suggests that the presence of a 80dB tone does not reduce hearing threshold when the frequency of the other low-level signal is sufficiently far away in frequency. Because you can see that detection level for higher order harmonics is lower in percentage as the volume increases, and if you plot this data into a frequency response chart, you can see that the detection level remains constant at threshold of hearing around 0dB, with a masking around the fundamental tone. The masking follows the level of the fundamental tone, but far away the detection level remains the same, regardless of fundamental tone loudness. The 80dB fundamental does not reduce hearing threshold, it only masks around the tone. Then we understand 2 things: - Dynamic range is at least 80dB for 80dB sound - Louder means more detail and more revealing to faults in the audio chain So, why did I not test for even louder fundamentals, say up to 120dB? That data could be interesting to have. When I did the test, it was for a different purpose, and 60 to 80dB was sufficient. Louder presents some challenges - more difficult to ensure that the only distortion present is what is being tested for, and listening to tones louder than 80dB up into the midrange is actually so loud it is quite unpleasant.
  11. Different subwoofers up front gives a different result. Swapping the V80 units for very small V6 shows no significant reduction in velocity when the sound source now is half the size acoustically. The difference in response (spl) and velocity are mostly caused by different location of the sub units, and the smaller ones roll of much earlier. At louder spl levels it is obvious there will be a difference where the larger V80 has the advantage, but the V80 system also sounds better at low volume. Having a large system makes sense even if the capacity is never put to use.
  12. That may be true, but that 140dB range does not apply for short time spans, because the ear has a built-in compressor that adjusts sensitivity according to exposed sound pressure level. If a very loud 140dB peak occurs, the sensitivity is immediately reduced, so that sound at very low spl can not be heard until the ears recalibrate, and that takes some time. Purpose of this mechanism can be to protect hearing, and also is the mechanism that actually makes it possible to have such a wide dynamic range. How large is the actual dynamic range, at a given moment, for a given spl exposure? Perhaps someone knows, I am sure there has been lots of research conducted on this. This relationship has attack time, hold delay, depends on peak vs rms level. This has consequences. We see that hearing is not a time-invariant system, because the output (what we hear) depends on what happened before in time.
  13. Seems I have posted too much, there is a limit to attachment uploads so I can not post the graphs. Solved by hosting images on my web.
  14. System 2 with subwoofers units located behind - spl is more flat, it does not extend very low, velocity is very different. V6030 is tuned much higher, so it is limited to around 25hz, and the placement is very bad for low bass. We see the v at low freq is much better, overall the v is higher in the bass range. This is expected, the units are quite large acoustically, so you are actually in nearfield in the listening position. We observe the same vertical 70hz resonance, so moving the subwoofers did not change the room. Some effects are due to the room-listening position interaction - will not change, others are caused by speaker boundary - changes when speakers/subs are moved. 100-200hz there is a dip in v, this would have to be investigated further to make this into a resonably good sounding system. First would be to find out what cause this, a new meas with fronts off would reveal if it is the interaction between front and subs causing the problem. It is not spl, phase, timing related (which you would see if you have the .mdat). This system does not sound good. You can easily hear bass coming from behind, and even though the tactile is quite strong, it does not feel right, something is missing, and it does not sound well integrated and coherent. Can you hear direction of bass? No, not below around 100hz, but the subs on cf 120hz will emit sound much higher up in frequency. Can you feel direction of sound? No, and yes. Very close to the sound source you can feel it, and I conclude due to the velocity and intensity being higher on the side of your body facing the sound source - now we are talking about sound that has so large velocity that it actually feels like wind on your body. Direction in itself is not perceivable, and once you get reasonably far from the source, you can not detect direction. (image hosted on my web)
  15. Looking at v in 0 (on-axis), 90 (sideways) and h (vertical) directions gives information about the direction of the sound. Direction reveals where reflections come from, and indicates the intensity of the sound. High intensity sound is directive. Here we can see that the 70hz spl dip is caused by reflection from the ceiling, because h direction v has a top in this same range. Up through lower midrange the sound field becomes more directional and resembles the outdoor free-field situation. Above 1K the measurement device is no longer valid. At low freqs the velocity drops, and that is not a good thing. But there is not much that can be done with that, unless one is prepared to do structural changes to the listening room - moving walls, closing off the open side wall door. For music it does not matter that much, and the low bass (<20-30hz) is experienced as airy, powerful, tactile. Sound intensity is the vector product of velocity and pressure, and there is plenty of energy to move the floor enough to create the necessary tactile feel. Sound intensity is what drives tactile feel, and vibration of objects. If we eq this spl response to flat - such as removing the 70hz dip, it will not sound more flat and balanced, because we induce too much velocity and intensity in the sound field in the range that already has a velocity resonance.
  16. What can we see from the velocity measurements. In addition to the normal spl we can get more information about what is going on when measuring the velocity. We can see the direction of the sound, resonances that does not appear on spl, cancellations of sound intensity. Ideally, the v should match the spl across the whole frequency range. If we measure outdoor, we see that this is the case when there are no reflections or standing waves or room modes present. In a room and with multiple sound sources, this changes dramatically. Here are 2 examples from the same room, 2 FL FR + bass system cf 120hz. System with 2 V80 bass horns up front, spl and velocity in on-axis direction: System with 2x V6030 behind, almost nearfield: We can see that the velocity does not follow spl at low and low-mid frequencies. This is caused by room acoustics and subwoofer locations. The 2. has better v at very low freqs, and there is less v around 100-200hz. This may actually be due to the sound waves from the front main speakers meeting the same phase sound from the subwoofers located behind, causing v to cancel out while spl looks good.
  17. Wanted to see Titanic, never saw it before. Watching the opening scenes reveals something is missing, and from what I can hear - such a pity. Can this be improved.. And it can. There is a steep 25hz high-pass, and doing the bass-eq magic retrieves some of the weight and natural balance that was lost in the studio because they had mediocre monitoring speakers. The exact numbers are on a different computer, but something like this: L,C,R: 2x sfm 22hz q=2.2 gain=+9dB, + eq to adjust for the inevitable midbass dip. LFE: 2x sfm 22hz q=2.2 gain=+9dB, 1x sfm 22hz q=2.2 gain +6dB + eq to adjust for the inevitable midbass dip. Much better, the helicopter in an early scene now sounds great, you can sense your hair moving as it comes around to land.
  18. One day I may elaborate some more on the velocity measurements - what is it useful for, what can you see and what is still missing.
  19. @dgage, I sent you a pm several days ago with this, I saw today you may not have read it yet, you should be able to see it in your Inbox.
  20. Exactly. The question is not IF the larger driver sound different, the question is WHY. Once that is established, we can move on and try to learn and find out what is going on. I think there is at least two different causes at play here. One is size of radiating area - the larger couples better to the air and creates sound with more intensity. But capacity is also important. Even if they play at same spl, the smaller driver can be at its limits, causing dynamic compression of transients. This will not be audible as distortion before you turn it up much , much louder. But the peak level of the transients are missing. I believe size is important from mid-bass and up into the midrange. At very low frequencies the size of one radiator is very small whether it is a 6" or a 24". But if you have 2 subwoofer units, they combine, and create a very large radiator together. If each of those units are very small, that does not matter.
  21. http://data-bass.ipbhost.com/index.php?/topic/404-understanding-and-optimizing-tactile-feedback/ I can send you a description on pm, the one that several others already have received. I just do not want to put it out in the open. Don't worry about OT, that decent audio forums are dying is far worse. And this is on-topic enough, just today I have set up, calibrated, measured and listened to 4 different bass system configurations in Room2.
  22. There is a thread about sub calibration & setup, actually two, search for the one with "tactile" in the title. You already have pressure measurement, but of course you already knew that. Velocity measurements are useful to see what you ended up with, if you have sub units both up front and back, it is also possible - to some degree - to change things with calibration.
  23. 8 sealed units makes a much larger radiator compared to 2 horns, it also depends on the horn, the drivers. Differences in capacity will also affect preception of the bass, and often at lower volume levels than you first assume. What you definitely can measure with the v meter is the direction of the sound - when everything is perfect, the direction will be along the normal axis from the front speaker system. At low freq the level has significance, but higher up in the mid and upper bass, intensity may be more important. v measurement can give you an idea of intensity because the intensity will be highest in a directional sound field. Timing and phase response also has significance. If I understand you correct - adding bass traps improved, and moving all sub units to the front wall improved. The bass traps improves everything, and especially the time domain, so that makes sense. Having all subs up front, close to the main speakers, should make it easier to integrate properly. And easier to achieve a good transient response. Subs all over the place has some very real problems with achieving a good time impulse response, and at the same time preserve sound field velocity and intensity.
  24. Much of this is already known - "it is known". We know delay and crossover must be right, we have an idea for how to do this, we know the frequency response must be reasonable. The interesting parts start after all this is roughly adjusted. Such as the character of the bass - a big system sounds better, even at low volume. How is that - certainly more than capacity comes to play here, because the difference is present at low volume, when a small 8" sealed sub should sound similar - according to simple theory. It does not. The difference is transient response and sound field properties - how the bass couples to the air. A large radiating surface couples better, and creates a sound field with more power and tactile feel, for the same spl. We have also experienced that a ported box has more impact than a sealed. In the new subwoofers I created a larger radiating surface, with high velocity output. It is narrow in one direction - giving the high velocity - and long in the other direction - acoustically large radiator. The horn loading makes it possible to make this in a practical subwoofer. A horn is different from a direct radiator, in that the sound has a higher velocity at the output, and kind of already has turned into a sound wave inside the horn path. The port in a ported box works in a similar way, the difference is in the tuning and that the horn port outputs sound across a much wider frequency range. The horn output works better even when the radiating area is smaller. This means it is possible to make a smaller subwoofer with the large sound. The smallest of the new designs measures 22cm x 22cm x 68cm (divide by 30 to get feet). Very small, and output capacity is also limited. At reasonable listening levels, you get that lively, realistic punchy character of the bass. Which of course makes you want more, so you turn it up, but that doesn't work so well, because you soon reach the capacity limit, the bass does not sound distorted or bad, but you don't get more of that addictive, powerful punch. Jøkleba - album Nu Jøk!, track Popcorn (Can be found on Tidal). When the bass drum comes in, it hits with a massive, powerful impact. Of course, at low volume you don't experience a hard, physical impact, but you can hear it is there. On the larger horns it certainly is very real and present when you turn up the volume, because they have more than 10dB more output, and wider frequency range. One of the largest surprises was the V6030 unit - a larger horn tuned to 30hz, for massive output. Here, the bass drum on Popcorn is very dynamic and powerful, and it does not fade off when you turn it up - loud.
  25. I have used this room to test a new series of compact horn subwoofers for some time now. Several new designs and many configurations, from very small subwoofer systems up to something that approaches the real thing. Part from the fun in testing and listening to all-new designs, here are some more general thoughts around bass in small rooms: - Subwoofers do not sound the same. Even with same type - horn - and the same driver, the tuning affects sound character. - Calibrating for a perfect and smooth frequency response is not the most important to get decent bass, time related problems are far worse. - Tactile feel is different from different subwoofers. Placement and calibration also affects this, but the subwoofer itself has huge significance. - A very small subwoofer can have a sound similar to a larger system if they are designed properly and the volume is kept reasonably low. - Subwoofers both up front and in the back (4 or more) gives much more flexibility for calibration, but is difficult to set up properly, it is easy to end up with worse performance compared to 2 up front only, and just forget doing this without measurements. - When you think you have heard it all, and think there is no more to achieve, you set up a new design and realize you were wrong.