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Everything posted by Kvalsvoll

  1. Bulding the Room2 listening room

    Posted this eminent solution on FB. It is basically useless for its intended purpose, but some will find it cool to use the phone to calibrate the stereo. Some phones will work, some will not. There are no speccs available, so you just need to try a phone and see what happens. If you have my horns, you can place the phone in the horn mouth, and see if you get a reasonably flat graph down to below 20hz - if you don't, the phone is useless.
  2. Bulding the Room2 listening room

    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:
  3. Bulding the Room2 listening room

    @SME, I only tested with a HTC, and that one looks good below around 1-2K, and down to at least 10hz. I have observed the SPL meter apps are popular, and they look nice and advanced, but I have always had my doubts regarding accuracy of those. Even a decent measurement mic needs to be calibrated, so what can you expect from a very cheap mic inside a mobile.. Dynamic range should be a concern for spl meter app, but for pink noise freq response can be assumed that the level is kept fairly low. I noticed there was not much correlation above around 5-8k, but below say 1k the response matched REW very well. Those spectrum apps must be set up properly, to show a graph with stable and correct response. This complicates the use. If I write my own app, it can be tailored specifically for this purpose, no settings or tweaking needed. If many phones have significant deviation from flat below 1K, that is actually a show-stopper for any app for speaker calibration. There is a point here were total complexity and cost becomes higher than the simplest REW + mic system - which actually works.
  4. Bulding the Room2 listening room

    How can you set up a bass-system if you have no measurement rig. Believe it or not, most people actually does not have acoustic measurement equipment. Here is how: 1. Download and install a spectrum analyzer app on mobile. 2. Download the <don't remember the name> full frequency range spectrum pink noise file from my web site. 3. Play the file on repeat and monitor what happens to the sound using the spectrum app. What can be fixed using this approach: - Setting level for bass system. - Adjust delay for main speakers. - Add custom parametric filters for horrible and obvious resonances. Very far from REW or similar, but compared to going totally blind this can fix integration and calibration to a level where many will be happy with the results.
  5. Bulding the Room2 listening room

    Just to continue, in between measuring the V110 in detail.. Frequency response is useful, as a tool - when used right. Tonal balance, potential resonances, getting the relative levels correct. It is also good for presenting a nice, smooth graph, after some heavy smoothing. Impulse is nice to look at, I use step response for bass. But it doesn't tell much about the sound. There is little correlation between perceived sound and the shape of the curve. Decay is important. Here the peaks that shows in freq can be analyzed, if they are resonances those will stand out as ridges, easy to see. Waterfall is great for show-off. Spectrogram is the other important graph. It shows how the sound start and stop, and reveals problematic reflections and decay.
  6. Bulding the Room2 listening room

    @SME, more knowledge often reveals that things are more complicated than you once believed, and you realize you don't have a simple answer anymore. Frequency response is always the first we look at, and its destroys the day as we see it is not completely smooth, there are obvious flaws that needs to be corrected. As we learn more, gain more knowledge and experience, we realize this is just one visualization of what goes on, and reading a frequency response graph to actually get useful information out of it is not that easy. It is a steady-state visualization, and most of the signals we want to reproduce are transient in nature. Right now I am working on bass-systems. Trying to find universally applicable methods and rules to set up the subwoofers. Does not help with a very good subwoofer, if it is not set up and calibrated properly. And in most practical cases, room acoustics efficiently destroys the possibility to achieve perfect sound in a simple and predictable way. Measurements are accurate and very useful as a tool to compare before and after when doing changes on the system. But to be able to say exactly how it sounds, by merely looking at the measurements, that is not easy. When I observe something about the sound, I try to find a way to objectively measure and quantify what I hear. Then perhaps i can be better at predicting how it sounds, and find ways to improve faults. The first thing, though, is to verify what I think I hear - not as easy as one might believe. Often it is necessary to rig experiments.
  7. Bulding the Room2 listening room

    @maxmercy, I have never heard one with drivers mounted across the whole wall. There are practical problems with SBA/DBA solutions - obviously. And - I may be scolded for saying this - I am not convinced they add so much more than a more conventional system can do, when properly set up and calibrated, and you can manage to somehow get rid of the cancellation reflections. From the experiments when I first found that velocity has significant impact for low bass perception - especially in the 20 - 50hz range - I also had a set-up with very much of that powerful wall-of-sound feel, and part of this has to do with getting more velocity than you get in the steady-state free-field condition. Similar to what you can achieve with near-field subs. A DBA done right will get predictable and very good results. Other solutions often end up with one part of the freq range having some special and very good performance, but then there are faults in other places. The trick is to achieve that special part, but at the same time be able to fix the bad parts.
  8. Bulding the Room2 listening room

    @maxmercy, yes, now, that is the question to ask. Fact is, I did not notice any huge difference. Even the 1x is as good as should be expected, and the 2x and 4x does not really have that much more, though they sound a little bit more tight and immediate, 2x a little better, and 4x even a little more. But I can not say there was a difference large enough in tactile experience to really differentiate the systems. The 1x hold up with bass-heavy music up to +3dB, enough for some tactile feel. But the larger ones can do much louder, and THAT makes a huge difference. ULF below 20-25hz is similar, as long as kept within limits. I still have 2x V110, so I can test some more, perhaps find a way to measure and get objective information.
  9. Bulding the Room2 listening room

    This is the tricky part. If the solution is to just eq to flat, it would be easy. But it isn't. Especially in the bass range, velocity and intensity matters. And you have to measure at different locations, at least cover different locations in height where the listener is located. Decay is important. Resonances will affect perceived tonal balance.
  10. Bulding the Room2 listening room

    Velocity measurements now available: Sideways velocity (90 degrees): Green is 1x configuration. Vertical (h): Red is 4X. Normal to front wall (0 degrees): Frequency response has a huge, narrow dip around 60-70hz. This must be caused by reflection from the back wall corners. This dip becomes progressively more deep and narrow as the sound field from the source gets closer to plane wave.
  11. Bulding the Room2 listening room

    @SME, inside a room the situation is complex, because boundaries are not rigid, there are windows, and sometimes openings, such as in Room2. These velocity measurements are only another tool to try to get more information, to get a better understanding of what is going on. Sound intensity and sound field properties affect perception of sound, we know that now. But velocity alone is only one part of this, and especially for higher bass frequencies - where chest slam occurs - it looks like intensity pressure is more important, due to the acoustic impedance properties of our body. To feel the sound moving your clothes, you need velocity. Also, frequency response and phase behavior have huge significance for perception, both what we hear and tactile. Just finished testing the V110 in the Moderate Cinema, to find out if it is suitable for movies. It is. But compared to the original T138 horn, it drops off a little below 20hz, above 15hz the V110 has more output, and should sound cleaner and more defined because there are no resonances left around the crossover, where the T138 no longer performs well in the time domain. I didn't bother doing a proper calibration, did not even use the default dsp settings, but the freq response looked reasonably similar to the T138, so I just left it like that. And does it sound better? Is it better to have this vertically large sound source? Does the effort put into the advanced design pay off in better sound quality? It does sound different, but not necessarily better. I suspect my lazy calibration approach comes to play here. The sub bass is experienced as similar, the level drop in the 10-15hz range does not seem to have much significance. The airplane-flyover-scene from Hanna sounds similar, Oblivion works fine, the storm in Kon-Tiki moves the whole house. Mid-bass is stronger and more powerful. Nice punch, and there is capacity available to turn it up, bass-heavy music at +6dB works fine, and then you add another +6dB on the bass system for that visceral feeling. Transients with large bandwidth lacks some of the precision and sudden impact. I blame this on my lazy calibration. Example - the cannons in Hunger Games. All in all, my conclusion is that the V110 works for movies. Same powerful bass transients with impact, like you are hit by a small shock-wave. Now I will look at the measurements to see if it is possible to see something there that corresponds with what I think I hear.
  12. Bulding the Room2 listening room

    @maxmercy There is not much correlation between velocity and spl. For the 1x config the spl looks like it follows the sideways velocity to some degree in the range where the 1x config partly fills in the cancellation dip. Velocity in 0 direction (normal to front wall) has a small dip where the cancellation occurs, but this dip in velocity does not follow the spl exactly. Especially in the 4x config the velocity is present where the spl drops off to 0. This shows that velocity and spl must be out of phase here. Just measured 3 V110 units. They are reasonably consistent, and matches the design sim quite well. Nearfield measurements at different locations in the horn mouth, and inside the horn path. I don't have any useful outdoor measurements, tried to measure the first one while moving it from the workshop, but with temp below freezing and windy conditions this was hopeless. It is also difficult to measure properly, due to the size of the radiating horn mouth - it is too long for 1m measurements, and the outdoor space is not large enough for good measurements at longer distances, may have to go up to around 4m to get correct results on the V110. Nice to see the smooth response across this wide frequency range, the rather complex internal construction with 4 damping chambers actually works.
  13. Bulding the Room2 listening room

    Yes, with 4x the measurements show that most of the velocity is head-on, as in a plane wave. It is also interesting to observe that the magnitude in the 0-direction (head-on, normal to the front wall plane) is the SAME for all configurations - it does not increase when sideways and up-down velocity decreases.
  14. Bulding the Room2 listening room

    Front wall has been like this since the room was built, it is 20cm Rockwool A with some slats, designed to work from around 100hz and up, which it does. There is a correlation, yes, but in this room, for this set-up, the frequency response is very similar for all those configurations. This is because the huge cancellation problem is a LENGTH reflection, it must come from the corners on the back wall. I did not believe that was the case, as there is a very large opening on the back wall, but those measurements show that a more plane wavefront from the front actually causes the cancellation dip at 60hz to be larger.
  15. Bulding the Room2 listening room

    3.35m wide, around 4.6m length - before adding the 20cm front wall absorption. So this is a small and quite narrow room. It doesn't feel cramped, there are openings on back wall and right wall, and having all walls white i suppose helps. But sound doesn't care about wall color, especially the width is challenging - little room for treatment to fix it, and since it is narrow, the side wall reflections hardly do anything good. Turned out quite nice, sounds reasonably good, but this small space requires treatment to work for high quality sound reproduction. Mind that quite many will find themselves in a quite small room, or constricted to a smaller part of a larger living room, for the music and sound. It is often better to use the longer wall as front wall - turn it 90 degrees - in a small room of such proportions. Then you would sit close to the back wall, which causes its problems, but also the advantage of not having to deal with back wall reflection in the bass range. There are some pictures earlier in this thread, showing the acoustic treatment with absorption and hard back with poly diffusors.
  16. Bulding the Room2 listening room

    @maxmercy, 4 units stacked (2 units stacked) near corners on front wall, so you get these systems: 1x: FL 2x: FL FR 4x: 2xFL 2xFR Let's see if it is possible to get a picture: I managed to take a full set of measurements before taking down the system. And they show that the systems have different sound field properties - but which one is better.. The 1x is all over the place, the 2x removes sideways velocity, the 4x removes both sideways and up-down. Yes, the 4x is better, but at any sane volume, it is hard to justify the double cost compared to 2 units. In a different room, or larger room, the situation may be very different. The 1x holds up surprisingly well, but it does not have enough capacity for that wall-of-sound feel that the 2x and 4x certainly has.
  17. Bulding the Room2 listening room

    @Ricci, I should comment on your excellent post, just too busy with the new subwoofers. If all subwoofers were specified the way you suggest, it would be possible to see and compare models, and decide whether capacity and extension meets requirements. Set up a system with 4x V110 in Room2, to test it, pictures on facebook (kvalsvolldesign). Easy to compare going from 1 to 2 to 4 units, with dsp presets ensuring similar frequency response and level - only capacity and sound field intensity/velocity are different. Interesting.
  18. Bulding the Room2 listening room

    FAQ is a good idea. Easy to add subjects. Those interested enough to consider buying use email. For questions and comments people can use the facebook page, it has both personal conversations and public comments. The blog posts has a comment option. I am now making a blog post on those specifications, basically the same text as above here, and I will add some examples and measurements to show how this works in practical situations.
  19. Bulding the Room2 listening room

    What are relevant and useful specifications for a subwoofer. A complete set of measurements, showing frequency response, capacity and distortion, is sufficient to tell how a subwoofer will perform. Then you can see how loud it can play at different frequencies, which is what you need to know for system design, you can see how low it can play and how loud. The graph also gives an indication of usable frequency range upwards. However, most customers don't really want to see lots of measurements, they do not understand what those graphs mean, and they acknowledge that fact. For the new Compact Horn subwoofers I did this: The output capacity number and the frequency range gives the necessary information. You want to know the output capacity to be able to dimension your bass-system, and you want to know the usable frequency range to see if it reaches low enough and covers all the range up to the desired crossover. The less tech-oriented customer still does not make much sense of the numbers, and is more likely to go by what I recommend. That's fine. The tech-experts needs to be educated on the meaning of those numbers, because they make no sense to them since they are different from what other manufacturers typically publishes. They don't recognize the meaning of Output capacity, and the frequency range is not the same as frequency response with specified tolerance limits. This is labor-intensive - requires lots of time and effort to educate and show. Perhaps these customers should be ignored - it's really a question of effort vs. value. One solution could be to make additional specifications and measurements available, so they can see exactly what the performance of the subwoofer is. The graphs still require some explanation. (The real experts usually get it, so they don't need any more education. They may ask for measurements, if they want more exact information.) Typical subwoofer specifications are useless. They say nothing about capacity, frequency range specifications are at best unreliable. One English manufacturer speccs a small egg-shaped subwoofer with two 8" drivers as "7.5Hz" - clearly very, very far off from reality. Another manufacturer makes a hairdryer with two 6" or close to that drivers, claiming "14Hz" - I have heard it, and there is no way to get anything useful out of it at that frequency, from what i heard, it struggled hard to do normal bass frequencies. Capacity is important to know because this tells how loud the subwoofer can play in the room. This is the number you use to determine how many units you need to achieve your desired spl at the listening position. Frequency range is the usable range - how low it can play at still somewhat useful output level, and how high up you can set the crossover. For a subwoofer, the frequency response is largely irrelevant, you only want to know the range, and as long as the subwoofer is designed for high sound quality the response will be smooth between lower and upper limit. If the curve is flat or tilted or in some other shape does not matter, because the in-room frequency response will be dominated by the room, and will need adjustments in dsp for optimum performance. ---------------------------- Since the real experts are on data-bass, this is the place to ask for opinions on this - how to specify subwoofer performance.
  20. The Bass EQ for Movies Thread

    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.
  21. The Bass EQ for Movies Thread

    I see you are one step ahead, you already know it works. And this system should give nice performance with BEQ movies. If you rip the movies to HD you can continue to use JRiver for eq.
  22. The Bass EQ for Movies Thread

    Yes, of course you need massive capacity and processing of individual channels. To explore the full potential. BUT. Quite many will claim that this subwoofer already is top-of-the-line, and most people does not have capacity and extension that this subwoofer can give. If BEQ is usesless on this system, then BEQ is really only for a very limited exclusive set of enthusiasts. Many of the moderately filtered movies can improve a lot with simple filters applied. And you don't need an extreme system to benefit from fixing the low end extension, it will sound better if there is extension down to below 20Hz and enough capacity to make it audible.
  23. The Bass EQ for Movies Thread

    I suggest checking out what is possible with the eq in the SVS sub. If there are suitable parametric filters available, you can try it on some movies, to experience and then decide whether BEQ is for you. You need a parametric low-shelf filter, with adjustable gain an frequency and q. Try some of the moderate movies, Oblivion is a one that only need a moderate lift at the lowest frequencies. If you find that this improves the experience, then you can start researching what equipment to buy.
  24. The Bass EQ for Movies Thread

    I don't know the Nanoavr products, but checking the mindsp web pages it seems the HD can do the job. Since it is digital in-out on hdmi, it will not have any negative impact on sound quality, part from the user setting up bad eq points. But check that you can actually use it, I believe it does not process TrueHD or DTS. We usually do BEQ by applying eq on the sound track in the movie file directly, which means it can be played back just like any other movie. But this requires equipment and knowledge do do it. If your bass-system has a dsp with parametric eq, you can use this to accomplish much - if not most - of the improvements. If the system has presets, you can program one or two presets with ulf bass boost, and select the most suitable one for the movie you want to watch. A simple approach, much more user-friendly. This will work very good on movies that requires modest bass eq, such as Oblivion, The later Star-Wars.
  25. The case againts subwoofers

    Don't read articles like this. The information presented is plain wrong and misleading. Some statements from the article: "music rarely has extremely deep, under-50Hz bass": Wrong. Most music has essential information below 50hz, and some music has content in the sub range below 20hz. In the 2-ch article I presented spectrograms taken from various music samples, which shows there is lots of low frequency information in various types of music. " most speakers with 5-inch (127mm) or larger woofers can muster 50Hz bass": No, a 5" driver can not even reproduce 200hz properly, if a realistic sound presentation is the goal. " Achieving the perfect blend isn't always possible -- subwoofer crossover tweaking isn't an exact science": Actually the integration part is science, and a manageable set of rules solves it. But you need the equipment and the knowledge to do it properly. If the sound does not improve after adding a subwoofer/bass-system, you did not do it right.