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Showing most liked content since 02/19/2018 in Posts

  1. 2 points
    I agree with much of what you say. I've thought about this for a while. Frequency response of subwoofers should have an output rating attached with it to keep things honest. Otherwise you get things like tiny 10" powered subs claiming 14Hz extension and other nonsense like you mentioned. For subwoofers I would like to specify a "useful" range and not worry too much about +/-3dB or whatever. What I do worry about is how much output a subwoofer is capable of. In my opinion this must be attached to the FR rating. These days almost anything can be equalized flat to very low frequencies. Who cares if it gets flat down to 14Hz if it can only produce 75dB? The way this would be kept honest is by attaching a detailed output rating to the lowest useful extension claimed. Too much detail is overload, but not enough allows specsmanship, or gaming the system. Balancing the 2 is tricky. The output rating itself has to have all the details necessary to make it comparable and honest. It must note whether the output is calculated or measured, microphone distance, whether it is a peak reading and whether the environment is full, half, quarter-space, etc. Distortion such as via Don Keele's tone bursts would be nice, but not required. Also absolutely necessary is the frequency used for the output rating. This is what I would like to see used. It keeps things as simple as possible, but provides the necessary detail for some sort of quick comparison. The attached measurements are from the dual opposed 24" sealed cube with 21Ipal's and a SP1-6000 amp as an example. There is a raw FR and the distortion limited and maximum output bursts. I'm using this one as an extreme example since it is sealed and has ridiculous upper bass output which skews the raw FR by a huge margin. Clearly no one would run this system sans EQ. Almost any bass system these days will employ EQ for response shaping. Certainly any active / turn key sub system for sale. It would be quite easy to make this response shape flattish to an arbitrary low frequency. Say 20-150Hz +/-3dB for example. Let's call that the FR rating and assume that was done. There will be a limit to how loud the sub can be pushed before it starts to limit the low frequency output and the response shape is no longer maintained. In this case the all out max burst of the sub was measured at 113.7dB at 20hz. I'd like to see the output rounded to the nearest 0.5dB so as not to get into splitting data points of less than 0.5dB between units, so let's call it 113.5dB. I'd call this "minimum output" or something like that. Many subs will also define a useful frequency range which is a bit looser (sometimes +-10dB) and beyond the tighter FR spec. This being a rather high output sealed sub we could reasonably call the useful lower FR limit as 10Hz. Let's call the "useful FR" 10-150Hz. That being the case we should also specify the max output at 10Hz since it is claimed to be useful. That would be 102.2dB all out with no THD limit. Rounded down to 102dB. A maximum in band output would also be useful. as we all know it's much easier to make something really loud at 150Hz than at 15Hz. Personally I think all subwoofers should be rated at 63Hz or lower for maximum output. 63Hz is a legitimate bass frequency which will avoid cheating and using peaks in output up above 80Hz (or even an octave higher) for a "sub". If the sub has peak output at a lower frequency great, however the DB the measurements show that to be a very rare sub indeed. 63Hz is also high enough in frequency that any cab calling itself a "sub" should be able to hit it in bandwidth with power. In the case of this sub we would use the 63Hz burst which measured an even 130dB. The ratings for this sub would look like this. Frequency Response: 20-150Hz +/-3dB / Half-space / 2m (assuming after DSP of course) Minimum output with rated Frequency Response: 113.5dB SPL@20Hz / Half-space / 2m / Measured Useful Frequency Range: 10-150Hz Useful Low Frequency Output: 102dB SPL@10Hz / Half-space / 2m / Measured Maximum Output: 130dB SPL@63Hz / Half-space / 2m / Measured
  2. 2 points
    v1 is 7 years running! v2: Just fixing some bugs and coming up with a migration plan. The migration is still pretty massive but I'm happy that we have got this far! The new site is going to be a huge upgrade and I'm excited to get this launched for the community Overall, not a lot of "new" features but mostly just making everything a whole lot better and easier to go forward/change improve. This gives us a platform for another 6 or 7 years. Old site SQL / PHP / JS Custom CMS build from ground up, limited features, small images, poor scalability. Shared server, not on cloud New site Tech Non-relational database Reactjs front end w/ custom CMS build in react/redux Most UI components are built from scratch with an updated look/feel Single page web app design provides a much richer user experience Template driven graphs for better control / flexibility and standardization of data Custom services (nodejs) for document storage with reliable payload validation for easier error handling and service construction Much better UI for image management Far improved CND store for images (using Amazon S3 and Lambda for on-the-fly image scaling/caching) Server is custom Heroku Dyno (Cloud based) with a .git repo UI Far improved readability and image UI Compare feature is more full featured and you can compare up to 4 systems at once. Added max output content section (similar to CEA2010, but no THD limits) Drivers now get their own graphs too. We'll port the impedance curves over.
  3. 2 points
    Ok...Finally got time to write up a post. Went back and updated the HR sim data for the Skhorn. The original sims prior to measuring the final speaker were not such a good match. Turns out my choice of placement of S3, S4 and S5 with the limited amount of sections in HR were not all they could've been. Incorporating the air volume in the driver cones rather into S2, instead of using Vtc and Atc, was a much closer match for this design. The other big improvement was moving S3 to the smallest section, directly after the drivers and incorporating the large air volume in the final corners of the horn section into S4. Sim is much closer now. Still not perfect, but probably about as good as it will get using HR. I believe I have learned another couple of tricks to make HR sims for horns more accurate by revisiting this but I'll need to verify in a couple more cases to be sure it applies to more than just this cab. Took some more time and looked at the Edge program vs measurements and sims and it lines up very well. Looky there the math works! Here is the new HR input for the Skhorn. This is the GP measurement of the Skhorn cab at 14.1 volts (normalized back to 1.41v) compared with the same measurement with the baffle effects as calculated by Edge removed from the measurement. Here is the measured response, once again using the Edge program cal file from the above graph, compared with the improved HR sim. This is a good match. This is the same graph as above but with the original HR sim from back before the cab was measured added in as the blue line. It was not a very good match.
  4. 2 points
    Very Interesting. While nothing here constitutes definite proof, it does seem reasonable to me that the streaming version is a cinema track mix-down; whereas, the BD version is a re-EQed dedicated home mix. As I've argued before, cinema tracks need quite a bit more low frequency oomph for good impact in an X-curve calibrated cinema. That's because X-curve calibration undoes the natural in-room bass rise exhibited by an anechoic flat speaker due to boundary gain and reverb build-up. Of course a lot of people at home also have systems with less bass output, either because they calibrate to a flat curve (e.g. Audyssey) or because their speakers lack BSC or because they have boundary interference problems. Nevertheless, it appears that recent BD releases with home mixes done at Skywalker Sound Studios have re-EQ to better match systems that perform optimally for music playback. In terms of the graphs, the streaming version looks 5-7 dB hotter through much of the sub region. However, the gap may be much smaller after compensating for loudness differences in the mids and highs. In that case, it may be more accurate to say that the BD version is hotter than the streaming version in the 15-35 Hz region. Certainly the shift of balance toward deep bass could reduce the apparent level of mid-bass, even if the SPL is similar after compensating for loudness difference in the mids and highs. There's a good chance I'll buy the BD version of this film. I may be tempted to try out the streaming version to satisfy my curiosity. I could give my opinion as to whether the streaming version sounds like it is influenced by cinema EQ, for what that's worth. That UHD Atmos tracks often sound louder than BD DTS-MA is a curiosity. Almost all DTS-MA tracks have "0" dialnorm offset, and I don't believe any format supports positive offsets. It's possible that a lot of Atmos "home" tracks are just mixed hotter than the cinema versions, from which the DTS-MA may be derived from. Unfortunately, there are still no formal standards for home mixing and apparently no consistency between studios. For example, I believe (based purely on my subjective evaluation) that Skywalker Sound Studios applies re-EQ to home mixes, whereas most other studios don't. Skywalker Sound also appears to have a dedicated mix room and to use a calibration/mix level that's comparable (in terms of room size differences) to cinemas, i.e. 80-82 dBC @ 500-2kHz. Such mixes are likely to sound quieter, in addition to benefiting from more headroom and cleaner micro-dynamics than cinema mixes. OTOH, it appears that some studios monitor home mixes with calibration as low as (or maybe even lower than) 75 dBC and may still be monitoring near-field in a large room. Such tracks are likely to sound even hotter than cinema tracks and have more potential for clipping and other problems. Also under those conditions, the need for re-EQ is likely to be much less obvious for a number of reasons: (1) tonal imbalances are much less obvious and offensive at lower levels especially excess brightness; (2) lack of boundaries reduces low frequency boundary gain that boosts the bass of flat speakers / mid-field monitors in "small" rooms; and (3) per Floyd Toole, rooms with early reflections are more revealing of tonal balance flaws in a speaker, and I'd argue that this extends to soundtracks as well. From my knowledge, near-field monitoring in a large room is probably the worst environment to monitor a home mix in. Simply monitoring the mix on the dub-stage system, albeit with a Harman-like curve instead of the stupid X-curve, is likely to offer better translation than "near-field". Somehow I need to get the industry people over to my house to listen to and compare mixes.
  5. 1 point
    Both Ragnarok and Justice had mediocre surround/bass mixes theatrically and that is translated perfectly to the home versions. They make Nolan mixes seem pretty damn good in comparison.
  6. 1 point
    I found the same issue and that's why we never used it in production as most of our products are used in quiet environments, also connecting to the controls I recall being tricky. I am not surprised that they derated it, hopefully that means there are some "hardwired" protections now implemented, because you could set it up in the DSP to be able to blow traces right off the main amp board with over current . This I found out the hard way .
  7. 1 point
    I had thought that was the case. Well...Now it is confirmed.
  8. 1 point
    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.
  9. 1 point
    I watched "9" tonight. My verdict? It sounds *excellent without EQ correction*. The dialog on the film sounds very natural and well-balanced with excellent mid-range clarity and just the right amount of fullness. It also goes without saying that the bass effects on this soundtrack are tremendous. The large hits are very wide bandwidth, combining both slam and weight. The "9" soundtrack is a reference for home theater audio systems in every respect.
  10. 1 point
    I like your format. Even though the room will dominate in the actual measured response, outdoor GP is the best measure, since all devices are on an equal playing field. A 'FAQ' or frequently asked questions section on your website can answer a lot of the same repetitive questions that can tie up your time replying to inquiries. Well informed customers can then email you for additional information on your products.
  11. 1 point
    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.
  12. 1 point
    When I first heard about it, I thought wave-field synthesis (WFS) sounded like a really cool concept. I'm a lot more skeptical now. Part of the problem is that a system of immense complexity (and expense!) appears to be required to achieve a high quality realization of WFS. Second, it's not clear that its really solving the right problem. In its ideal realization, WFS can synthesize a complete, spatially consistent (or spatially-dependent, if so desired) sound field within a listening space. This is basically the Holy Grail of audio. If an entire sound field can be reproduced in the space perfectly, then the reproduction is absolutely true and correct. In reality though, WFS cannot be realized ideally with any practical configuration of existing components. As a consequence, there will be errors in the reproduction. On paper those errors may be fairly minimal, especially compared to the gross distortions to the sound field induced by the effect of acoustic boundaries in a "normal" system involving speakers playing in a room. However, it turns out that people are very well adapted to listening to sources reproduced in rooms with complicated acoustic effects; whereas, they may not be that well adapted to listening to the errors that arise from WFS. From some reading, it would seem these errors have been minimized enough for the strengths of the technology to be fully appreciated. That is encouraging, and I'd certainly like to hear a setup some day. I'm sure it has its benefits and its applications. Though I can't help but wonder how much better the tech could be if wasn't so obsessively focused on creating a perfect / anechoic sound-field replica and instead took advantage of the acoustics of the space its in to achieve a smoother, even if less "correct" sound. Edit: I forgot to add that I'm in the early planning stages of trying to build my own arrays consisting of many independently-controlled elements, to be used as surround and/or Atmos speakers that provide far more even seat-to-seat coverage than conventional speakers could achieve. I'm not sure if the approach I plan will look like WFS or not, but I have rather different objectives in mind, so who knows?
  13. 1 point
    Lots of things are spec'd to 10 or 20Hz but work pretty well lower than that. Hopefully this is one of those cases.
  14. 1 point
    NEW playlist: The Demo Tracks - Advanced: Moving into more advanced territory, with music that requires more both from you as a listener and your sound system. https://tidal.com/playlist/4337c9a0-0405-48db-94ac-7dfd5fe6e46c # Title Artist Album Time 1 Poppkorn Jøkleba Jøkleba! / Nu Jøk? 3:20 2 Shopenhauer Jøkleba Jøkleba! / Nu Jøk? 3:47 3 All Through the Night Emancipator Safe In the Steep Cliffs 4:33 4 Rattlesnakes Emancipator Safe In the Steep Cliffs 4:10 5 Kleine Dreigroschenmusik (Arr. for Chamber Ensemble) - VII. Cannon Song: Charleston-Tempo Chicago Pro Musica Medinah Sessions 2:20 6 Shamanimal (Live at Satellit Café) Hadouk Trio Utopies 7:10 7 The Golden Striker The Modern Jazz Quartet No Sun In Venice 3:41 8 Vals (En Vivo) Puente Celeste En Vivo en Cafe Vinilo 3:56 9 Buey (En Vivo) Puente Celeste En Vivo en Cafe Vinilo 7:58 10 Taquito Militar La Segunda Será Una Noche 3:35 11 La Roca La Segunda Será Una Noche 5:06 12 Ascent Lyle Mays Lyle Mays 6:59 13 Flowmotion Vestbo Trio Flowmotion 4:19 14 I Love Paris (Live) The Hot Sardines Live At Joe's Pub 5:17 15 Rainfall Daniel Herskedal Slow Eastbound Train 3:37 16 There Are Three Things You Cannot Hide Love Smoke and a Man Riding on a Camel Daniel Herskedal The Roc 5:01 17 Pink Froid Infected Mushroom Converting Vegetarians II 7:40 18 We the Dub Yore Salmonella Dub Dub for Straights (1993 Sessions) 3:44 19 Dirt Bikes And Street Vendors The Flashbulb Soundtrack to a Vacant Life 1:55 20 Swollen Trees The Flashbulb Soundtrack to a Vacant Life 2:28 21 Rose Hierarchy The Flashbulb Nothing Is Real
  15. 1 point
    Tidal playlist "The Demo Tracks Part 1": Description Assorted demo tracks, put together from the collection built while listening to Tidal in the Kvålsvoll Design Room2. This is the "popular" list - music which is easy to like. Some of these tracks are often played in showrooms and exhibitions. This is not a selection of productions with exceptional technical qualities, rather examples of diversity and variation both musically and in sound style. Some have obvious flaws - if your sound system is good, it will still present the music. Tracks on playlist 1 How It Feels (Album Version) Sophie Zelmani 2 Ticket To The World Ayo 3 Cocaine Eric Clapton 4 Tin Pan Alley (AKA Roughest Place in Town) Stevie Ray Vaughan & Double Trouble 5 Summertime (Alternate Take) Janis Joplin 6 Trampled Underfoot Vanessa Fernandez 7 When the Levee Breaks Vanessa Fernandez 8 Here I Am Now Steve Gadd 9 Be Brave My Brightest Diamond 10 Train Song Holly Cole 11 Little Things India.Arie 12 Us and Them Anne Bisson 13 I Miss My Love Anne Bisson 14 Island On An Endless Plane The Flashbulb 15 Four Women Malia 16 As Time Goes By Viktoria Tolstoy 17 Get Lucky Daft Punk 18 Royals Lorde 19 Goodbye Yellow Brick Road (Live in Atlanta) Sara Bareilles 20 September in Montreal Anne Bisson 21 Stay Yello 22 Everything I Need (Album Version) Keb'Mo' 23 Le vent souffle encore Vincent Bélanger, Anne Bisson
  16. 1 point
    Just wanted to mention a side-effect of having a true full-range system, something the typical data-bass reader can relate to; You sit down in the carefully located listening chair, put on some quite ordinary music - jazz with vocal, acoustic instruments, perhaps some classical with a small string quartet ensemble. Sounds nice, the ears warm up a little, and you increase the volume slightly, usually end up keeping it at 0dB. Then - suddenly, out of nowhere, this string quartet makes the whole world kind of shift as a very powerful pulse of ulf noise makes your heart stop. You don't really hear it, you feel the air blast and the movement . Like in a well-done action movie - except that in the movie, it is expected, appropriate and part of what makes the experience better - and you are don't get scared. It is obvious that not only movie production studios lack low frequency reproduction capability, music studios have the same limitations, and they don't need it either for the string quartet. Except when someone stomps the floor, or touches the microphone housing, and a microphone picks up this and creates an earthquake on the sound track. If the recording is processed full-range, and no one checks for sub-20hz noise using a spectrum analyzer, this will go unnoticed. Until I play it on my system. At 0dB. Lots of recordings have ulf noise that is audible, and some have these occasional potential heart-attack inducing monster transients.
  17. 1 point
  18. 1 point
  19. 0 points
    Tonight listening to music fairly loud, hitting the peak limiters in the iNuke 3000 DSP, suddenly I had red rings of death. I did have a saved preset file, and also some screen shots of the DSP settings. The amp made 6 years before it failed.