Ralf11 Posted October 8, 2018 Share Posted October 8, 2018 doesn't BXT increase SPLs at lower freq.s? (despite no extra bass extension) Link to comment
TheStupidOne Posted October 9, 2018 Share Posted October 9, 2018 Yes, but unless you play loud enough to draw advantage of that spl capability it doesn't matter. On some tracks where there's information below 30 hz you might trigger the first standing wave enough to become audible with Bxt and not with Kii alone, but most likely it's not a big issue in reality. Link to comment
Emlin Posted October 10, 2018 Share Posted October 10, 2018 Has anyone seen any proper and full specs for the BXT? Kii promised them for Q3 when they launched them back in May but there is still nothing more on their site, where say that even the footplates are still not finalised. Link to comment
TheStupidOne Posted October 10, 2018 Share Posted October 10, 2018 Other than that Bxt plays up to 250 hz, I haven't seen any specs. I want to know how loud they can play at 20 hz continuously and how hot they get at, say, sustained 85 dB over a period of time. I'm not overly confident that passive cooling is sufficient when the top plate is covered by another heat source (Kiis) and I'm certainly not confident that my living room will be survivable when another 8-16 amps start throwing heat around. Link to comment
barrows Posted October 10, 2018 Share Posted October 10, 2018 8 hours ago, TheStupidOne said: Other than that Bxt plays up to 250 hz, I haven't seen any specs. I want to know how loud they can play at 20 hz continuously and how hot they get at, say, sustained 85 dB over a period of time. I'm not overly confident that passive cooling is sufficient when the top plate is covered by another heat source (Kiis) and I'm certainly not confident that my living room will be survivable when another 8-16 amps start throwing heat around. Hmmm? Do you listen to music with a constant 20 Hz drone at 85 dB? This is a really weird request. Indeed it would take some energy to produce that level at 20 Hz, constantly, in room, but consider that the class D amps used are around 85 % efficient. Now, consider that if you wanted to create that same level using class A/B amps, which are around 50% efficient at best, you can see that the class A/B amps in a conventional system would heat up your room much more than the Kiis, so I am not understanding what your concern really is? Just because Kii uses many small amps to produce the SPLs does make them produce more heat, many small amps will work no harder (total output watts) to produce a given SPL than one big amp. On the other hand, it sounds like you might be looking for a PA system rather than an audio system: are you looking to DJ with them for dance parties in convention halls or something? Then get a PA. SO/ROON/HQPe: DSD 512-Sonore opticalModuleDeluxe-Signature Rendu optical with Well Tempered Clock--DIY DSC-2 DAC with SC Pure Clock--DIY Purifi Amplifier-Focus Audio FS888 speakers-JL E 112 sub-Nordost Tyr USB, DIY EventHorizon AC cables, Iconoclast XLR & speaker cables, Synergistic Purple Fuses, Spacetime system clarifiers. ISOAcoustics Oreas footers. SONORE computer audio | opticalRendu | ultraRendu | microRendu | Signature Rendu SE | Accessories | Software | Link to comment
Emlin Posted October 11, 2018 Share Posted October 11, 2018 I've emailed Kii about the BXT specs. We'll see what they come back with, as I'll post it here. Link to comment
TheStupidOne Posted October 11, 2018 Share Posted October 11, 2018 On 10/10/2018 at 5:07 PM, barrows said: Hmmm? Do you listen to music with a constant 20 Hz drone at 85 dB? This is a really weird request. Indeed it would take some energy to produce that level at 20 Hz, constantly, in room, but consider that the class D amps used are around 85 % efficient. Now, consider that if you wanted to create that same level using class A/B amps, which are around 50% efficient at best, you can see that the class A/B amps in a conventional system would heat up your room much more than the Kiis, so I am not understanding what your concern really is? Just because Kii uses many small amps to produce the SPLs does make them produce more heat, many small amps will work no harder (total output watts) to produce a given SPL than one big amp. On the other hand, it sounds like you might be looking for a PA system rather than an audio system: are you looking to DJ with them for dance parties in convention halls or something? Then get a PA. No, I don't listen to a constant 20 hz drone at 85 dB. What a weird question. ? I want to know what output they can do at 20 hz because I want to know if BXT can replace the need for subwoofers in a dedicated room; tilted room-curve, ear sensitivity and headroom all taken into consideration. Why continuous output? Because I want to know the real-world performance; thermal compression, thermal distortion and heat protection included, not the hypothetical best-case scenario. Why continuous 85 dB sound level? Because I listen to music mostly around 70 dB on average, maybe 75 dB when I get frisky. Taking the tilted room-curve I like (roughly +6 dB from 200-20 hz) into account and allowing for some headroom for electronic music and movies where there can be sustained low frequency output, I'd say 85 dB for reference level is quite reasonable for a bass system. You can actually barely hear 20 hz at 85 dB. Why worry about temperature? Because Class D amplifiers, although efficient, still emits about 2-3 % of their rated power output as heat - at idle. I don't know if there will be 4 or 8 amplifiers per side, but there will nevertheless be quite a few heat-sources within a confined cabinet without active cooling. Heat will not be dissipated as quickly through passive cooling inside that cabinet as it would be if the amplifiers were out in free air, so heat will build up to a certain extent and - disregarding concerns about over-heating - will act as two more ovens in the room. Of course, this issue is no different from the Kii Threes themselves, but I'm concerned it could be one of those things that builds up to become a problem. With more heat emitting from the surrounding airspace, passive cooling will become less effective, which will lead to more heat build-up which will lead to even less efficient heat dissipation which will... possibly make it damn hot in a room. So that's the practical part of the equation, the theoretical part has to do with thermal distortion. Considering the price, I need to compare BXT to other solutions which may or may not give more for less and I need to do it by getting some facts I can work with. Link to comment
Emlin Posted October 11, 2018 Share Posted October 11, 2018 Kii were quick at getting back to me with this: you are absolutely right that we are a bit late with this.We will post this on the website in the coming days.Its a bit busy right now with about three trade shows every weekend.I am sure you will understand.The serial base plates are in production and will ship with the serial production models of course - with spikes and all.I hope you can find the chance to give the Kii THREE BXT System a listen on one of our many occasions.All the best and thanks a lot for your interest. Chris Reichardt Link to comment
sapporo Posted October 11, 2018 Share Posted October 11, 2018 Attempting a continuous 20hz signal with some power on those little dinky drivers is a good way to drive them beyond mechanical limits. Link to comment
TheStupidOne Posted October 12, 2018 Share Posted October 12, 2018 There's a self-protective circuit on board protecting the drivers from exceeding their limits, so that shouldn't really be a concern. Link to comment
sapporo Posted October 12, 2018 Share Posted October 12, 2018 So it's enough to know the parameters of the protective circuit, no need for tests. Link to comment
TheStupidOne Posted October 12, 2018 Share Posted October 12, 2018 If you only want to know the maximum driver excursion possible, then you can calculate the maximum output at any given frequency from the parameters of that circuitry, yes. But I didn't ask for theoretical best-case scenario, so that doesn't really help me. Link to comment
sapporo Posted October 12, 2018 Share Posted October 12, 2018 Kii Audio says that BXT is 16 drivers with 7000 watts of amplification. Probably half of those drivers are working to create the cardioid forward pattern and don't contribute to the final sound pressure*. 8x 6 inch drivers have the area equivalent to 3 x 10 inch drivers. Without knowing the excursion it's difficult to compare displacement. Let's assume it is similar. The 7000 watts is obviously the peak power of n-core amplification. The continuous thermal limited power will be max. 1000 watts (see nc-500oem data). The cooling is through the aluminum driver membranes. By comparison a Geddes style distributed sub system (eg. Audiokinesis Swarm) will deliver at least the same total SPL (probably more) for a quarter of the price. It goes down to real 20Hz too. Quality-wise I bet on 4 distributed subs along the walls vs two cardioid ones. I tested Kii Three in that respect and if BXT is more of the same thing, distributed subs win for me. *obvious oversimplification Link to comment
sapporo Posted October 12, 2018 Share Posted October 12, 2018 PS the cardioid pattern is limited to some frequency, can’t find the exact figure now. Link to comment
Kal Rubinson Posted October 12, 2018 Share Posted October 12, 2018 2 hours ago, sapporo said: PS the cardioid pattern is limited to some frequency, can’t find the exact figure now. The Kii controls the relative phase and timing between its rear and front drivers and between its side and front drivers to create a cardioid dispersion pattern from 1kHz down to below 80Hz. Above 1kHz, the directivity of the front-firing drivers, due to their size and location, dominates. Below 80Hz, as boundary gain dominates, the Kii becomes increasingly omnidirectional, but that can be dealt with by a relatively simple adjustment of output level in that passband.Read more at https://www.stereophile.com/content/kii-audio-three-loudspeaker#EBiRuAEorp7LvYMm.99 Kal Rubinson Senior Contributing Editor, Stereophile Link to comment
sapporo Posted October 12, 2018 Share Posted October 12, 2018 So if under 80hz BXT is omnidirectional this becomes a very expensive pair of subs with typical sub issues. Except they aren’t meant to be moved around. Link to comment
Emlin Posted October 12, 2018 Share Posted October 12, 2018 Bruno Putzeys has made it clear that they are not subs. Line array and increased headroom are what they bring to the party. Link to comment
TheStupidOne Posted October 12, 2018 Share Posted October 12, 2018 There's no question that several distributed subwoofers will outperform BXT in out-and-out bass performance with the added benefit of dealing effectively with the room modes, so that in itself shouldn't come as a surprise. I've already shown in this thread how much better two cheap subwoofers + Minidsp placed on opposite walls perform in-room vs Kii Three alone, but I don't think I mentioned that a single 15" sub far outperforms them in sheer output and physicality because it kind of goes without saying. If you are considering BXT then you should consider the benefits (better sound due to less floor-bounce reflections, more punch and more dynamic capability) against potential downsides (might vary depending on perspective) and price. Link to comment
Ralf11 Posted October 12, 2018 Share Posted October 12, 2018 18 minutes ago, Emlin said: Bruno Putzeys has made it clear that they are not subs. Line array and increased headroom are what they bring to the party. a lot more than that - did you read Kal's post? or his review? BTW, bdy gain is often called bdy loading Nonetheless, they are very expensive and have some other 'relative detriments' so some of use will just have to hobble along with Maggies for awhile... Link to comment
Emlin Posted October 12, 2018 Share Posted October 12, 2018 2 minutes ago, Ralf11 said: a lot more than that - did you read Kal's post? or his review? BTW, bdy gain is often called bdy loading Nonetheless, they are very expensive and have some other 'relative detriments' so some of use will just have to hobble along with Maggies for awhile... I was talking about the bxt only. Link to comment
sapporo Posted October 12, 2018 Share Posted October 12, 2018 30 minutes ago, Emlin said: Bruno Putzeys has made it clear that they are not subs. Line array and increased headroom are what they bring to the party. Can you point to this quote from Bruno? I am curious what the constructor says about BXTs. Link to comment
Emlin Posted October 12, 2018 Share Posted October 12, 2018 Not this second, but it's in Johnny Darko interview with him on YouTube. Should be easy to find. Link to comment
Popular Post Emlin Posted October 13, 2018 Popular Post Share Posted October 13, 2018 5 hours ago, sapporo said: Can you point to this quote from Bruno? I am curious what the constructor says about BXTs. Here it is: PorkChop and hvbias 2 Link to comment
Popular Post atletico Posted October 13, 2018 Popular Post Share Posted October 13, 2018 Feeding my Kii Threes with some high class vinyl...sounds great in my living room. Video and sound from my iPhone 8. I will soon be audition the BXT system but I'm not sure how this could take my already great sounding system to a higher level, but I'm really curious what the BXT could do... IMG_0014.m4v hvbias and TheStupidOne 1 1 Auralic Aries G2 - Kii Control - Kii Three active speakers - OPPO BDP 95 - Clearaudio Concept turtable / AT-33 PTG II pu /Clearaudio Maestro Wood pu - Rega Fono MC riaa / Musical Surrondings riaa Head-fi: Beyerdynamic DT 1770 Pro - Shure SE846w/Silver Dragon - Chord Mojo Link to comment
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