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  1. Yesterday
  2. Maximum horn compression ratio?

    Thanks for the lesson guys. The knowledge level here is amazing. I know that's pretty basic for you guys but I'm just fine with having other people design drivers for me and with knowledgeable people like all of you, can you blame me.
  3. Maximum horn compression ratio?

    The BL^2/Re is the ticket. The Qes or Qts are influenced by Kms (suspension stiffness) and Mms (effective moving mass) as well. Higher values of either parameter increase Qes and Qts while affecting efficiency at either frequency extreme. Higher Mms reduces efficiency at the high end. Higher Kms reduces efficiency at the low end, although the K of the air spring in a small sealed box can overwhelm the effects of Kms in the final product. Comparing the IPAL-18 to the HST-18mk2, the HST has approximately double Mms but only about half the Kms of the IPAL-18. So the influence of these parameters on differences in Qes/Qts is kind of a wash. The IPAL-18 will offer much more upper frequency efficiency overall. The HST-18, while having quite a bit less BL^2/Re will still hold its own pretty well below the resonance frequency in an I.B. or large sealed box. As the box size is reduced, the HST-18 loses the benefit of its more compliant suspension and the efficiency advantage of the IPAL-18 will widen. However, note that the stronger motor of the IPAL-18 has a downside, at least in a sealed box. The stronger motor will tend to increase the back EMF around the system resonance, requiring higher voltage (but not power) to drive it. This problem is substantially mitigated by its very low resistance, provided that the amp is capable of operating stably under such conditions and capable of delivering the desired amount of power within the lower impedance parts of the response within the desired bandwidth. And of course, the IPAL -18 may require some signal shaping (EQ) to achieve the desired in-room response, but this may be true for either driver depending on the room. On the other hand, a ported box will tend to increase the sensitivity of a driver for frequencies near and a ways above the port tune, which can offset much of this effect. A horn will tend to increase sensitivity (and efficiency) even further, and the higher back EMF may even be more desirable for a flatter native response.
  4. Maximum horn compression ratio?

    Dave, BL rating means nothing alone. That does not tell you the effective efficiency or "strength" of the motor /coil system. Resistance also has to be considered at minimum. BL^2/Re Or just look at Qts Technically the normalized inductance should also be considered as it effectively saps the efficiency and raises Qts. You need to include 3 parameters at minimum. BL, Dcr and Le. Or like I said just use the easy button and compare Qts, though that doesn't consider Le effects.
  5. Maximum horn compression ratio?

    How are we comparing motor force? The Bl for the HST-18 is higher than the Ipal. But you also mentioned efficiency, yep, different ball park and design goals. Sorry to take this off topic as I was just wondering. Definitely not trying to say one driver is better than another.
  6. Last week
  7. Maximum horn compression ratio?

    Compared to an 18Ipal almost everything has lower motor force / efficiency. Of course the HST 18 has like twice the displacement capability though.
  8. Maximum horn compression ratio?

    I understand the HST-18 might not work in your situation but I’m a little surprised by the comment of not enough motor force. Are you referring to the mkII driver or the original as the mkII uses the same magnet-motor as the HS-24 mkII. And the HST-18 mkII is an 80 lb driver, mostly magnet. I’m not trying to be defensive or suggest that the HST-18 is the best driver ever but I want to know what drivers you’re looking at if you consider the HST-18 MK II to have low motor force.
  9. Maximum horn compression ratio?

    Sorry, I’m using the HST (in a vented box) only as a comparison. It’s my baseline. It’s just there so I can convince myself the horn is worth the extra effort over a conventional ported box. The system I’m trying to work out is the horn, which uses a B&C iPal 18”. The HST wouldn’t work for the horn; Qts is too high and motor force is too low. At least per the numbers, 2” is enough clearance for the B&C, since it has a 20mm Xmax and folded surround. It’s not much, but it shouldn’t be hitting the other side of the chamber!
  10. Bulding the Room2 listening room

    @SME, I buy all music I know I want to hear often, everything on local disks is the only way to go. In a world where companies sees shorter lifetimes, you never know when your streaming service shuts down, and all the music is gone. Why doesn't Bandcamp work? At least you can buy and download? Tidal requires a Win pc, and it is only a coincidence that i have one in Room2 - I bought a small, white laptop because I wanted a white one, and later realize it is not possible to get linux on it. Chesky has good sound, I have some if it. I also see you like Infected Mushroom - though that is something quite different. If you have any more listening impressions, I am reading.
  11. Maximum horn compression ratio?

    In my 18” subs using the HST-18, I allow almost 4” above the mounting surface to allow for excursion before the grill.
  12. Maximum horn compression ratio?

    I see that you also have a throat depth of just over 2". Have you seen how tall the surround is on an HST? Are you sure this enough to clearance the surround at full excursion? Im not sure how a surround like that will fare in a high pressure horn loaded app. It might be fine but I have never seen it tested. Things to consider.
  13. Bulding the Room2 listening room

    I listen to all sorts of stuff, and I'd be hard pressed to identify much that's really "demo-worthy". I'm rather more inclined to demo stuff that's familiar to other people, especially if they bring their own music, and some of the few tracks I have with more significant dynamic range. For that purpose, I like a lot of the stuff done by Chesky Records. I think I already mentioned "Clark Terry - Live at the Village Gate", which I find to be a very immersive and dynamic recording of a live jazz performance. Another album I have that I routinely go to is "Ana Caram - Amazonia". IMO, it's an all-around excellent latin jazz album, and the vocalist is superb. There are other Chesky recordings of Ana Caram out there too, but I have heard them. Another one, recommended by Bob Katz is "Pacquito D'Rivera - Portraits of Cuba". The brass on that one will really test the high frequency section of your system and your ears too. All of the above are, IMO, very dynamic recordings that I typically play in the low negative single digits or even at "0" and were likely mastered 10-12 dB louder than typical loudness war stuff. They also use relatively minimalist micing techniques and deliver a very nice sound stage, if you speakers are able to recreate it. I also have a fair number of decent classical recordings, but I need more. Unfortunately, most classical (as well as most big band) just doesn't have enough dynamic range to do it justice. I've noticed a lot of more recent recordings that have moderate dynamic range (i.e., comfortable playback at "-5") but have annoying clicking artifacts from the digital limiters in use. Some are much worse than others, but being familiar with the artifact, I find myself hearing it a lot more than I want to in things that otherwise sound fantastic like the "Star Wars: TFA" score (on the BD,; no idea how the CD sounds, but it's probably way more compressed). Reference Recordings is a label that offers some fairly dynamic stuff including some organ music with real extension, but I find a lot of their stuff to be unrealistically hyped at the top end (cuz, it sounds more hi-res that way?) and often distorted in the livelier parts due to limiters that just don't sound as natural as good-ole-fashioned analog saturation. Other than that, I like a wide variety of genres: classical / symphonic of various eras, jazz (especially latin jazz), folk, rock, blues, 80s (mostly wife's stuff which is a bit more alt than pop), etc. I also love a wide variety of world music, from celtic to reggae to raga to middle eastern. Genre-crossing fusion stuff is great. I like certain kinds of EDM a lot, but am real picky. IMO, there's a lot of garbage including most of the stuff that was popular back when I was young. I really like goa/psy-trance EDM though. Once I discovered it, I kind of stopped bothering with most of the other stuff, which just sounded slow and unimaginative in comparison (IMO). I did like some DnB stuff, but I didn't really pursue it as eagerly as I did goa/psy-trance. I kind of got more into the culture of the latter, even though the "scene" was practically non-existent here in the states until Infected Mushroom and Shpongle and whatnot started making the rounds. By then, I was too busy doing grown up stuff to really party more than once or twice a year, and those parties were tending toward more of a crazy dark-psy sound with even higher BPM (compared to older psy-trance which was quite fast at 145-180 BPM+) and sometimes chaotic, glitchy rhythms. A lot of that stuff was likely from artists that never managed to publish as widespread piracy pretty much killed any potential for commercial sales. More than anything else, I listen to electronic psy/ambient/dub stuff, mostly stuff that grew out of the goa/psy-trance EDM movement, which tends to be infused with more world music influence and is more focused on structured bass beats than pure free-form space stuff. A lot of the music I have I collected back when this stuff was unheard of here in the states, but of course it was only a matter of time before these sounds branched into other forms like dub-step, which went on to influence pop music of today. The vast majority of this electronic stuff is not especially dynamic, and overall sound quality is definitely variable. On the plus side, the mixes often contain a diversity of instrumentation, both acoustic and electronic; they tend to be bass heavy or bass driven, even though extension below 30 Hz or so is pretty rare; they make ample use of phase-based panning including outside the front stage; and they use *lots of reverb*. All of these are qualities benefit from a system capable of accurate reproduction. I just don't tend to play most of this music at especially high levels. Most was probably mastered at close to "-12" or "-14" like typical pop music, and most of my listening is fairly casual in which the volume is more likely at "-20" to "-30" or less. If I'm in the mood for a more involving experience, I'll probably push things up closer to the mastered level. There are always exceptions to these things. A few odd tracks have impressive extension and/or slightly lower loudness including a lot of stuff from "Infected Mushroom". The compilation album from Interchill Records "Gathering the Tribe" has 20 Hz extension and is a bit less loud than average, and I do sometimes crank things up into the minus single digits on that one. If you find yourself liking this kind of music, try to get a copy of the BD "Shpongle - Live at Red Rocks" as it's a real gem. (I know I've already mentioned that one.) The album releases I have by that group are rather loud and a bit rough sounding in the highs, but that BD is super smooth and has excellent dynamics and very convincing replica of the ambience of the venue, which I happen to live near and have been to on several occasions. Yes. I noticed the album had a characteristic sound similar to other selections by the artist you posted. Thankfully it's a lot less offensive than it was in previous iterations of my system EQ config. At "-6", it was definitely a lot louder than I would normally listen. For a more typical but "fully-involved" listening session, I would probably choose closer to "-12" or "-14", which I presume is where it was mastered. And for more casual listening, I'd use a similar level to most of the rest of the music I "commonly" listen to. At those levels, I doubt I'd have any problem with the sound, even though its slight edginess would still be noticeable, just as it is with some other albums I own and like. Indeed. I am more confident in the accuracy of my system now than ever before, but significant differences will always persist, no matter how close to perfect our systems may get. Do keep in mind that sound quality problems are a lot more forgiving when the level is lower. On my last config, I found anything about "-13" to be pushing it a bit, so being able to push up to "-6" while keeping things mostly comfortable says a lot about how even "small refinements" can make a big difference in a system's sound quality. I'm really surprised by how loud I can play a lot of stuff now without really experiencing discomfort. I thought the trumpet had fairly significant distortion, which was probably done on purpose. Though for me it just seemed way too overbearing. Maybe my ears were just tired from the high levels they'd endured before it. After "Piety", I played the song from "Yello" and then immediately followed that by "Metallica - One (live)" from "Through the Never" on YouTube. The last selection I played at a full "0", and it was not especially harsh even at that level. However, when the music stopped, I noticed temporary threshold shift (TTS) for a few minutes afterwards, which was not apparent from the previous selections. From what I understand, TTS is a warning sign of potential damage, which suggests that sound harshness or unpleasantness does not necessarily correlate with damage. It's possible for sound to be very clean and comfortable and yet be quite damaging if listened to for long periods of time. Thanks for posting all the selections. Most of that stuff I haven't heard. Unfortunately, I don't have access to Tidal, and Bandcamp playback recently broke for me for unknown reasons. When I did my replay, I had to rely on YouTube, for better or worse. Even with YouTube, things are dicey these days as Firefox recently stopped playing well with Linux audio. It's not the fault of Linux but simply programmers who don't try to understand how the system is designed. In the case of Firefox, it's fond of opening the audio device and keeping it open, preventing other apps from using it, so I have to divert it to a fake device until I want to actually play sound with it. I'll probably resurrect my Roku some time soon, which I had disabled because it hijacked and completely broke my HDMI chain, presumably due to buggy CEC support. At least it'll do YouTube, and if the phase of the moon is right, I can ChromeCast from my phone. Alas, I don't get why the young'ns rave about the convenience of digital streaming. For me, it's nothing but inconvenient. I'm much more likely to buy a DRM-free download or even an old-fashioned redbook CD than to try to stream. Mind you, I was streaming music all the time back in the late '90s and early '00s when the protocols were open and DRM hadn't infected everything. Now everything is locked-down and walled-off and the artists still aren't making any money, except from a few services that actually care like Bandcamp. Hence, I'm real sad that Bandcamp broke. I guess people on this site can relate to the fact that almost all streaming TV/video services only offer audio in stereo. How lame is that? They're offering us 4k (albeit at bitrates that deliver quality that's still inferior to BD) but only 2 channel audio? Get real.
  14. Maximum horn compression ratio?

    EDIT: modelling with lossy Le like Ricci suggested makes a big difference. The horn compression ration to achieve an OK response becomes more reasonable, down to about 1:4. The horn flare has to get wider, though, resulting in a shorter and fatter box. I'm re-posting lossy Le results with the HST-18 vented box for comparison. These are presumably more realistic. On the bad side, the box is getting a bit wider than I'd hoped.
  15. Bulding the Room2 listening room

    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
  16. Bulding the Room2 listening room

    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
  17. Bulding the Room2 listening room

    @SME - what music do you like, perhaps you have some examples from your own collection? I listened to the tracks you describe, to try to get a better understanding of what you mean. First, in the Moderate Cinema, then in Room2. Paying attention to the properties you describe. What I do notice is that the highs has a characteristic sound - the tonality is colored. like the frequency response at higher freqs has large deviations, and the level is a little loud. I listened to several Flashbulb albums, and find that they all have this sound to them, more or less. I certainly do not think you experience this because your system has some fault, it is likely more neutral than any "high-end" system tuned by matching cables. Measurements don't tell the whole story, they are difficult to interpret an so on it goes, but a mic and rew is actually the most powerful tool we have, and used properly it results in more neutral sound, and usually better sound. And yes - the 2 systems here sound different, I would say very different - even though a simple frequency response chart shows quite similar curves. I did not find the trumpet to be harsh or strange. Now I listened at -30dB - it is very late, but tonal character tends to be quite similar regardless of volume, it just gets louder when you turn it up. And eventually it gets too loud - does not matter much how clean it sounds, when the ears overload. Some other Flashbulb albums (www.bandcamp.com if they are not on tidal): Reunion: Dynamic and powerful sound. Try "God Is Speaking". Kirlian Selections: Quite similar in sound, but perhaps more diverse and melodic. Try "Kirlian Selections III" - guitar quite close, violin to the left, deeper and further away. Soundtrack to a vacant life: Rougher, less refined sound, note full frequency range. Try "Forbidden tracks". But for judging sound quality, this may not be the best choice of music, especially if you do not know the music from before. Something like Vanessa Fernandez - Use Me has better overall sound quality, and there are less strange sounds and instruments that we really can not know how is supposed to sound. Flashbulb is because I like the music, and also the characteristic sound - it is not supposed to sound like Vanessa Fernandez.. Did you see the Tidal playlists I published? Perhaps I could post the list in text format, so that it is possible to see without using Tidal.
  18. Bulding the Room2 listening room

    I revisited this album today, after my latest system configuration using FIR filters and offering significantly smoother highs and upper mids than before. This album is definitely a lot more listen-able (at high level) than it was before, but the qualities that made it sound harsh to me are still present. It has a distinct upper-mid/high push, and many if not most HF transients are clipped. The pumping with low frequencies seems even more noticeable now. All of these are among the usual tools (or side-effects of those tools) used by mastering engineers to achieve a louder sound while preserving a subjective sense of dynamics. I listened to most of it at "-6" ("-7" really, if I were calibrated precisely with pink noise to 85 dBC), and at that level, plenty of content still exceeded my comfort threshold. I can't imagine listening at "0" except for maybe single songs on a one-off basis. At "-6", some stuff was uncomfortable. The cymbal-like sound in "Fog", while relatively clean (for the album), was more upper mid than I wanted to deal with for the full length of the song, so I turned it down. Likewise, the trumpet in the last song is just plain harsh, even at modest volume. If you're listening to this at "0", then you must either have a tilted system response or a much higher tolerance for loudness than I do. In terms of overall loudness, I perceive this album to be no less loud than the majority of content these days. I don't know if it's meaningful to ask whether or not the heavy pumping with the bass was intentional. I am fairly certain however that the bass impact in this track would not have been possible without either the pumping or a substantial drop in loudness. The bass hits by themselves likely used every bit of headroom on the track. For comparison, I also pulled up "Yello - Stay" right afterwards. The vocal on that track is definitely heavily distorted, and while I thought it sounded "bad", it did not induce discomfort to my ear. I would say that the vocal distortion intentional or else it was a terrible recording (or both). The rest of the sound was quite smooth and, in some ways, a tad less loud than the Flashbulb album. The transients were not clipped as aggressively if they were clipped at all. So other than the vocal, I did not find it to be an especially harsh track. The issue (if there is one) is in the vocal recording or processing. By comparison, "Piety" has harshness in the mix/master. "Piety", of course, had no shortage of highly distorted samples as well, but these were almost certainly made to sound that way on purpose. With that said, it's OK if we disagree on these things. Every system sounds a bit different, and I know this probably better than most, having heard my own system with easily hundreds of different EQ configurations. What one hears is a consequence of the source material and the system linear (and to some extent non-linear) response combined. Flaws in the reproduction system can either enhance or suppress flaws in the source material. Though, I'd also add that flaws are more likely to enhance one another than suppress one another. Clipping is perhaps among the most egregious flaws because it introduces a broad spectrum of high frequency energy, which tends to emphasize every HF linear response flaw in the downstream system and often cascades to cause more clipping. It's something audio engineers should go out of their way to avoid because its' effects on the sound are so unpredictable from one system to the next and are typically worse on less capable systems. Anyway, I do like the powerful and extended bass on "Piety" and wish more content was done this way, albeit with more headroom and less pumping. Musically speaking, it's not quite a style I prefer, but I do listen to a lot of stuff that's similar. It's pretty rare to hear this kind of music with any extension beyond 30 Hz or so, and it really does make a big difference, even at more modest levels, IMO.
  19. Maximum horn compression ratio?

    No worries! I have considered the thickness of the main panels but I haven't yet included the bracing. That will cut down the area further, of course (or expand the box). Thanks for the tip on particle velocity. Audio folklore is that velocities should be below 10 m/s, and this gives a good rationale for this horn, I think. I had been struggling to justify all this extra carpentry versus my first design, a Stereo Integrity HST18 low-tuned vented box. Why do all the work and have a larger box if I can get the same SPL at low frequencies just by getting a bigger amp and using a conventional low-Fs, large-Xmax driver? Well, if port velocity is the measure of distortion we care about, the horn wins. I modeled both at the same RMS voltage, and at the voltage where the horn throat is hitting 10 m/s at its peaks at the horn mouth, the vented box is hitting 20 m/s at port tune at the mouth and and is over 10 m/s over most of its range. If we look at SPL, the numbers are less benign. I'm not sure what a bad value threshold is here, but we do see high pressures over more of the range at the horn throat, while the vented box is bad at resonance but much lower overall. Any ideas what SPL limit the throat should be limited to? Maybe a throat adapter could mitigate this? Yes, the fold was key to the design. I did a good bit of math to get the fold sorted. The idea was to use the expanding radius of the accordion fold to create the flare, rather than tilt the wood panels at precise angles and struggle to crumple the fold into the box. This allows a very long horn path to be crammed into a not-completely-insane box in a fairly simple-to-construct way, i.e., via a sort of matroyshka-doll structure. I'm not sure if there's a penalty to pay for the fact that the fold only really flares as it rounds the corners; I was planning on a more detailed Akabak model to capture this if it works out in Hornresp. If this thing goes anywhere, I think it needs to be called the Longhorn. No connection to Texas, but it seems pretty obvious given the length of the fold.
  20. Maximum horn compression ratio?

    I will look at this when I get a chance. Very busy at the moment getting some more tests ready to upload. Off hand. Interesting fold. Have you considered weight of the cab and internal pressures at high output? Bracing of the panels etc? Check the particle velocities, acceleration forces and pressures at the throat and exit. They will likely be extremely high with such a high compression ratio. Also absolutely model with the Le option checked which derates motor force some.
  21. Maximum horn compression ratio?

    Here's the hornresp parameters, the frequency response, and a 1/4 cutaway view of the box with the accordion-fold layout I intend to use to get enough path length to get down to 10Hz. The frequency response isn't audiophile flat, but I only intend to run this up to 60 Hz, so I should avoid most of the really choppy stuff. Below that, it doesn't strike me as unreasonable, especially with some room gain and EQ shaping. Feel free to critique! This is my first horn, so if there's any obvious blunders I'm making (besides maybe a too-small compression ratio?), I'd be glad to hear about it.
  22. Thank you for your kind words. This process has been enormously challenging and time consuming, but results (so far) are immensely rewarding. I never imagined sound of this level of quality was possible, in this space or otherwise. I remember when I first moved into this house in December 2012 and set my system in the living room for the first time. The sound was so disappointing. My original plan was to try to finish part of the basement for a dedicated room, as soon as I could afford it. However, the basement options were full of ugly compromises. In one area, I would have 14 feet of width but would have to deal with ceiling obstructions with only 6 feet overhead clearance. The other part offered a full 7 feet of headroom but only 10 feet of available width. I had to come to terms with the fact that the basement options would be suboptimal regardless and decided to try to make the best of the living room space instead. Today, I could claim to have a set up that approaches "world class" performance, all while leaving the living room largely functional, albeit with lots of weird looking panels and diffusers. Thankfully, my wife has been very accommodating. Her skepticism toward acoustic treatments melted away once she heard the difference. She also happens to be quite the bass lover, lucky me! ... Some day I need to update the first posts on this thread to describe my "current" configuration. Right before @lowerFE's visit, I migrated my speaker DSP configs to use FIR filters almost entirely. I also modified the crossover to 850 Hz LR8 (acoustic). The FIR filters are much cleaner and more precise than the mess of biquads I was having to maintain. The horn/woofer crossover is also linear phase, which I opted for not so much for sound quality improvement but to eliminate group delay that confounded my tonal balance calibration method using short FDWs. The result provided a significant improvement, albeit not as dramatic as some changes in the past. Still, it was worthwhile enough for me to demo with the FIR filters, despite the fact that the bass still needed work. So @lowerFE was able to hear the speakers sounding as good as they ever have, but the bass was not as good as I think it could have been. In fact, I ended up making substantial changes on Saturday night, between his visits. On Saturday, the main/sub XO was linear phase, and I ended up redoing everything to minimum phase XOs and less aggressive shaping to reduce pre-ringing. That was kind of a hard lesson for me, which is that pre-ringing really does bad things to bass transient response and tactile sensation. The problem was most obvious to me when listening to the Danley fireworks. I could actually perceive the pressurization before the bang happened. Even with those changes, some pre-ringing persisted and is present in my current config. I don't know how perceptually important that is though. Since @lowerFE left I've EQed down the 70-100 Hz range a bit, as it was subjectively too strong, but the bigger change was to move my bass boost from being centered at 70 Hz to being centered at 155 Hz instead. I decided to try to better mimic the floor gain from a "typical floor standing speaker". I had tried bass shelves at higher frequencies like that before, but it seemed to work a lot better this time. The extra mid bass really brought more punch and overall loudness to the table. Now I'm trying to figure out how to reduce pre-ringing further while maintaining smooth frequency response, keeping excess group delay in check, ensuring coherent summing across multiple channels, and doing all of this at every seat location. It's a remarkably complicated problem, and while I have powerful DSP to attack it with, it's not at all obvious how best to apply this capability. I also have a problem of a rattling window pane (at around 60 Hz, unfortunately), so I am trying to reduce the bass build-up in that corner to keep it from rattling as much. I intend to eventually try to optimize using an automated algorithm, but automation is useless without a precisely defined objective. And in the long run, I expect I won't be able to get the results I want with the equipment I have. I still intend to replace the MBMs I have. The open question is *where* I'm going to put the new MBMs. I can put some of them behind the sofa like the old ones. I can also put some of them on top of the subs, between the subs and left/right mains. (The "pseudo-line" approach.) And I can put some up on the shelve above the TV, adjacent to the center channel. The locations behind the sofa are starting to fall out of favor with me because it's difficult to avoid pre-ringing problems. In fact, I can't really avoid pre-ringing in the dining room and kitchen areas when using behind-the-sofa MBMs without using multiple switchable DSP configs, which I'd like to avoid. So I'm curious if I can get away with MBMs on the front stage only. I think the approach has potential, given how the center channel measures. That is something I will investigate in due time. Some time, I might start a thread about bass phase response / group delay. It seems to be a substantially neglected issue with regard to system optimization and may have a strong bearing on tactile response performance. While it seems counter-intuitive that minimum phase crossovers may (often) be superior for mains/sub crossovers, minimum phase systems actually appear to have the properties we want most. We want as much energy as possible to arrive at the start of the impulse. Too much positive excess group delay, and energy does not arrive until too late to contribute to perceived impact. (Post-temporal masking effect.) But any pre-ringing has the effect of shifting the perceptual reference point, the "start of the impulse", to a place where there's very little energy at all. (Pre-temporal masking is very weak.) So what achieves these goals? For a particular magnitude response, the minimum phase response maximizes the amount of energy in the initial impulse. I suspect that this is what's needed for the best tactile "kick".
  23. Maximum horn compression ratio?

    I have, and the numbers look good with high compression ratios for sure. That’s why I’m curious if I’m missing anything. I’m more worried about what hornresp doesn’t model than what it does. For instance, it’s not going to model driver failure! It doesn’t know anything about the strength of the cone or the surround glue or whatever. On the other hand, if it does model distortion, I’d be interested to know about it. I haven’t seen that, only frequency response, max SPL, etc. Nothing about distortion.
  24. Maximum horn compression ratio?

    Depends on the driver and the horn design. Driver diaphragm will limit the load it can handle, shape of the horn close to the driver affects how large pressure and flow creates distortion. Huge motor force is good in a horn, and - as you experience - you end up with larger ratios. The problem is not so much the high velocity at the throat, because it is large pressure gradients - pressure changing rapidly - together with large velocity that creates problems first. This causes flow separation and then turbulence, which means distortion, noise and efficiency lost. Too high pressure at the throat causes nonlinearities due to the nonlinear properties of air. Model it, simulate, and look at the numbers.
  25. Maximum horn compression ratio?

    Hi, I’m planning to build a tapped horn subwoofer around the BC iPal 18, which models very well in hornresp due to its extremely low q (0.14!) and high motor strength. There’s something magical about this driver; nothing else I’ve modeled manage to get as low with as reasonable a response curve in a not-too-absurdly-huge box. VERY low: I’m planning on scraping 10 Hz if I can! One problem I’ve run into, though, is that the horn compression ratio wants to be quite high, for both response curve smoothness and to keep the box size reasonable. Something in the range of 1:6 all the way up to 1:10 works best. Now this is far outside what is typically quoted for subwoofers, which are supposedly recommended to be held around 1:2, with 1:4 a typically quoted maximum. I’ve read two reasons for this maximum: avoiding excessive horn air velocity and thus distortion, and avoiding simply overstressing and blowing the woofer cone itself. However, I haven’t heard a good *quantitative* reason why the recommended ratios are chosen. If there are any. Since this is databass, I hoped I could get a data-driven discussion on the real limits of horn compression ratios for subwoofers. Is the old 1:2 ratio just based on wimpy older drivers, and is outmoded by the new generation of crazy motor force neodymium magnet woofers, or are there some very good reasons to avoid going too high? How high, exactly, could you go, before you run into problems? Is 1:6 ok? What about 1:10? I’m thinking of something like Ricci’s dual opposed 21 iPal build, which clearly ignored the typical rules of sealed box design and overwhelmed the limits of the tiny air volume with the iPals’ high motor force. If this can be done for sealed boxes, maybe something similar can be done to create mini-horn subs.
  26. Had not got T5 yet on video but will eventually. People love to poop on Michael Bay and T5 has serious issues but in a hobby for A/V..... T5 brings it. Interested in the Atmos track and if it is (better be) a remarkable improvement from T4's barely-Atmos track. And yes... let's bring back the days when 20hz was cool cuz it still is, imho.
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