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Bossobass Dave

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Everything posted by Bossobass Dave

  1. Luke, are you saying only a 1000W amp is needed to power the HS-24 because of a 10 Hz shaped burst result with a Fi 18" driver?
  2. Paul and I just tested a pair of 14000 watt amps from China. They look nice and cost less. They sported low speed, temperature triggered fans, almost silent with low output. In 4 ohms bridged they lasted less than one scene (beach scene from X-Men FC) before going into over temp protect and one of them failed catastrophically immediately thereupon. The fans just couldn't catch up with the rapid rise in heat of the output transistors in time. Single digits, +10dB L/T boost and lots of current. There's no cheap version of amp that can deal with that. As I said earlier, even if the protection circuitry kept the amp alive, what good is the amp that needs constant protection during movie playback?
  3. I imagine everyone is engaging in humorous hyperbole here, but just in case... One driver (doesn't matter which), driven by an amplifier that is capable of pushing the system to it's limit, plus some headroom equals 'x'. Add another driver so that you now have 2 of them and that equals 'x' plus 3dB. It will equal 'x' plus 6dB if you also add a second identical amplifier, assuming proper mains for 2 amps and proper placement in the room that results in only constructive reflections across the system's bandwidth (not likely, but we're playing around with numbers here). Now, add two more drivers so that we have 4 identical drivers in identical boxes and that equals 'x' plus 6dB. Again, go to 4 identical amplifiers with proper mains and the system gives an added 12dB. Double the driver/box count again and assume perfectly harmonious placement and you have 8 identical passive subs that potentially equal 'x' plus 9dB. Go to 8 identical amplifiers, each on proper mains, and you have 'x' plus 18dB. Using the HS-24, the 18dB potential increase in headroom over a single driver/amp system means eight PowerSoft K-20 amplifiers, eight dedicated 220V-50A home run outlets and eight HS-24 drivers, each in a proper size enclosure and placed perfectly in the room. If a single version of this system has a max top end of 126dB at 30 Hz, where room gain begins, and there are zero destructive reflections from eight of them in-room, you have headroom to 144dB from a system that only cost $60,000, with no signal shaping or EQ hardware. Yes... very likely.
  4. No, we won't be offering it. We looked at 3 versions of the so-called 20000Q. It doesn't give 20KW and may or may not last more than 10 seconds depending on what source and system it sits between. Zero out of 3 ain't good. But hey, it seems that Rob Mosher is the guy to ask about that sort of stuff. He claims to be able to deliver one for half the price from the Top One Chinese agent. He still apparently recommends Sanway for clones, so maybe ping JT and ask him?
  5. OK, it looks like this forum has been totally abandoned. I wish Nube would check in just so that I know he's OK.
  6. Yep, when you get more specific with the 'different subs', we'll be more able to answer the question. Bass players are a rare breed. I had a friend who used to have lots of folks over to his house 2 or 3 times a year. Drums, amps, mics, etc., were all set up. In the summer, it was in his awesome back yard and in the winter, around this time of year as a matter of fact, it was indoors. Paul and I used to go there and wail some hits. It was the best time. Sadly, he passed away suddenly at a very young age. I miss him and I definitely miss the jam sessions with musicians of all kinds.
  7. Thanks for the kind words. It means a lot after the hard work. IMO, a listening space is either one for critical listening of music or HT. They are two completely different animals. For example, one would never invite multiple listeners into a space and have them site randomly, as in a HT situation to view a movie, and suffer under the delusion that everyone in attendance will be able to critically listen to music. There is only one seat in which one can enjoy a proper sound stage. In fact, there is one very specific placement for one's head while sitting in that seat. Movie viewing at reference or near reference levels, which is assumed when the owner of the HT space is considering a 14,000 watt amplifier to power his subwoofer system alone, makes fan noise irrelevant. If I listen critically to MC SACD (I don't listen to 2 channel CDs at all, ever), I also listen at average levels of around 90dB with 100dB plus peaks. The only time fan noise is an issue is if I want to ride the end of a tune that happens to have a very slow fade to 0dB. Of course, in that case, any fan noise will override the music at some point in the fade to zero. Again, if critical listening of music were the goal, I would not need 14,000 watts of amplifier on an 8 x 15" subwoofer system. I would simply use the Stewart fanless class D 1200watt amp or similar connected to a single Blackbird module when music only listening. A Critical listening NC-15 room is a relatively rare item. It has it's place, but in a HT with state of the art sound, not so much. As Adam noted several times on these boards, a typical projector has quite audible fan noise when no media is playing.
  8. http://data-bass.ipbhost.com/index.php?/topic/22-the-data-bass-member-equipment-list/?p=9979 I sit 10 feet (3M) from the amps. When sending the multiple subs an identical mono summed signal, that is the signal that should be shaped. It makes little sense to split the signal and affect it's shape separately. Separate subs in mains towers is something I'll leave you to tell me what is best as I have no experience with the scheme.
  9. Yes, I had pics of 3 systems. Only 2 were fired up for the GTG. My actual system, which has been in the corners all along, was not connected. When you were here I had my system 3 connected. The 3 modules that were still in the room were from the shootout, one with the Raptor BHT-15 drivers, one with the LMS-R drivers and one with the HST-15s. None of those were connected. Every system I've had in the HT since 2003 has accurately reproduced what's on the disc.
  10. There is not 3 systems in there. Adam's breaking balls. There is "only" a single System 3 running. That's because one side is an original prototype stack in which I originally used D2 drivers, so it's a nominal 4 ohms. The other side is with MKII drivers that I switched to D4 VCs to get the loads right to run both systems from the same amplifier (one stack = 8 ohms nominal and wiring 2 stacks parallel is 4 ohms nominal). If I wire the existing 4 ohm stack to the 8 ohm stack in parallel it comes out to <3 ohms and I don't want to run a single bridged amp into that low a nominal impedance. Wiring the stacks in series yields 12 ohms nominal and that's not ideal either. So... I run one amp bridged into 8 ohms and the other amp bridged into 4 ohms. Honestly. I did 16 x 15" a long while back when just to test the results. At reference level, 8 x 15" had plenty of headroom, so going to 16 x 15" at reference level made no difference on the SPL meter or on SpecLab. Topping 135dB is doable with a System 3 (8 x 15"), but not in full bandwidth mode. I'd have to engage a curve that includes the 18 Hz HPF. Now, if you want to exceed 135dB at full bandwidth with the usual suspects demo scenes, you need 16 x 15" in my room. In fact, I just got around to re-calibrating the system yesterday. I set the subs to flat with the OPPO SW trim at -5dB. That way, I can run the subs as much as +5dB hot without worrying about the stupid OPPO gross distortion when exceeding '0' SW trim level. I also affected a -3dB Hi-Shelf from 4k Hz and up to trim the top end a bit. Sounding pretty darned good.
  11. Understood and thanks for the input.
  12. Firstly, we're talking about multi-KW amplifiers. The Class A/B or B output stage is 60% efficient. (Amplifier efficiency is a complex subject, so the numbers cited are a bit arbitrary. Ours is an average number based on several data inputs). Simple math shows the potential amount of heat that may be necessary to dissipate. The huge increase in heat sinks and the addition of a 5th cooling fan to the so-called "clone" platform should be telling enough regarding whether or not we think the fans can be rendered silent for a fanatic who might be known to stop listening and track down a fly whose buzzing is annoying him. Selecting the +10dB BOOST option with NO HPF option in a Raptor system gives maximum extension. That's because the native low end response of the system is altered to work with typical room gain to provide flat-to-5 Hz response at the seats. To accomplish this, the lowest frequency content of murderously difficult soundtracks like "9", X-Men First Class, Battle:LA, How To Train Your Dragon, et al, are boosted by a factor of times 10. So, imagine the playback level set to achieve peaks of 120dB. That would mean transients requiring, say, 1,000 watts. BUT, the extreme low end is boosted times 10, so they require bursts to 10,000 watts. And, those watts are being applied to amplify frequencies from the Netherworld, where audio enters another dimension previously unknown to humans. Switching from volts to amps of current at impedance minimums to reproduce incredibly dynamic source that includes single digit frequencies that are dredged up from the depths of dimension 'X' means a few things must be coped with that normally can be ignored: 1. The efficiency of the amp (that means ANY amp, class notwithstanding) drops when the impedance of the load drops. 2. The heat rises... QUICKLY. 3. The output transistors heat rating can be exceeded faster that the modified cooling apparatus (read: fan mods) can prevent the problem. Seaton mentioned in the SP amp thread that: So, "no amplifier is the perfect solution", "robust low impedance protection circuitry costs $$" and "protection is handled by a custom programmed micro-controller" that address "even some differences between those sold to the home vs pro use". We agree. The A Series amplifiers are meant to bridge the gap between three to five RU 100# plus amplifiers whose max output sits at around 5KW and the latest class D, non-bridgeable low end amplifiers that can't keep their spec while reaching into the Netherworld and the SpeakerPower/Powersoft class of amplifiers, cost-wise. If fan noise is such that you can't relocate or adequately sequester the amp and fan noise is a deal breaker for you, buy the SP/PS amps and call it a problem solved with extra $$. On the low end side, we hope that no one will buy one of those offerings and delude themselves to think they perform equally, but life is what it is and we can't influence that. Every physical operational noise reduction scheme modification we attempted to implement on the A Series amps... every one... ended in premature amplifier failure. As a results of our tests, instead of reducing the cooling efficiency, we increased it. Now, let me be clear here. Most people who build a sealed , horn or ported subwoofer do not apply the sort of signal shaping boost we and others DIYers use to mate system and room gain to achieve full bandwidth playback. This is a whole nuther ballgame, thus some other random posts about fan mods being successful. No frequency response, no signal chain data, no playback measurements, etc. We're not saying no one could mod fan noise and get away with it. We are, however, saying that any failure associated with modifications made to the A Series amplifiers is not covered by warranty. In my theater, I have 2 A-14K amsp, a Marathon MA-5050 and three QSC RMX amps, all installed in a dual-console: I always leave the doors open enough to allow adequate air flow to the amps, so they aren't actually isolated in another room, like Adam's are, but maybe Adam can chime in here and comment on the fan noise in my HT as he's been there a couple of times watching movies. I don't find it a problem and if only one A14K was running, I doubt I'd ever even think about it, but... that's me. Sorry for the long answer, but it's an important subject to address in detail.
  13. I wanted to make a post regarding amplification of a for real home theater subwoofer for those who are new to the hobby and for vets who haven't yet been introduced to a piece like Paul's new Dash V signal shaper. "XXXX" asked for one of the first Balckbird prototype dual opposed 2x15" subs as a passive solution. He said he had his own amp and wanted to add low end to his smallish system in his new open floor plan LR/DR/Kitchen. Paul set it up and the sub rendered a typical presentation of usable in-room response to around 25 Hz with roll off below that and very high output above 30 Hz. Then Paul suggested a test run of insertion of his then prototype Dash V. Of course, in-room response went from "Wow" to "OMFG!!!" with the usual suspects of demo scenes. The problem though was immediately apparent. The Crown amplifier he had tapped out immediately. The source, signal and sub were asking for more than the Crown with shared 15A mains can deliver. I've been there myself many, many times. In my naive beginnings as a full bandwidth seeker, I used the Marchand Bassis with a 1/12 octave sine tone CD with a bandwidth of 10 Hz to 120 Hz, the RS SPL meter with C weight correction file and hand-drawn graphs to measure the difference between native response and signal shaped response. Here's a scan of one of those exercises. Please note that these were done close-mic and then you'll see my ignorance of the subject. Let's stretch that to a typical REW graph scale and gee was I happy with myself... Of course, the amp shat the bed immediately. I upgraded to higher power and the drivers wrinkled and melted. I then went on to buy 100 drivers from a half dozen countries. I also began to study the awesomeness called Room Gain. I then ended up with: 8x15" Adire Tumult (4xMKI and 4xMKII), each driver powered by one QSC RMX-1450 MAX (11,600W on shared 20A mains) per driver with +12dB L/T BOOST. After a decade, the Raptor Systems are, each driver, powered by 1750W MAX (A-14K on dedicated 30A mains) with 6dB/8dB/10dB BOOST and NO/10 Hz/18 Hz HPF options. Point is, try powering a single Raptor module with "XXXX's" Crown with the 10dB BOOST, NO HPF curve selected and watch the clips lights flash all night instead of the movie. Keeping the roll off low, the response in harmony with the room gain profile, the gain matched, the noise low, the power adequate and the drivers safe equals a state of the art low end presentation. But, the choreography is specific and necessary and the amp needs to hold up its end of the deal.
  14. Sorry for the confusion. The A4-12K-TT is available in 120 and is the upgrade price check box version, so you would add the 220V up charge for the 220V version. The A4-18K-tt is 220V only, so the upgrade price obviously includes the 220V up charge. NOTE: International customers will hit a roadblock when they get to shipping. If you select, for example, Australia, you'll get a flag that says there is no option for shipping to that location with a link to contact us. As I said, we're still looking into those options and working out the bugs. If you're interested in any of the amplifiers and you live outside the CONUS, just use the main bossobass.com e-mail link to ping us with your request and we'll address it specifically for you. There is not a lot of profit built into any of these separate hardware options (as of now, the amplifiers and Dash V options, more will be added as they come on line), so we just have to look at each individual request and see if it's feasible to make both sides of the transaction agreeable.
  15. You guys are on the ball. I just launched the sites and have been working out the bugs in the shopping cart, payment gateway, shipping, e-mail response, etc. New Bossobass masthead, every page re-done, new pages added, Special Edition Raptor subs and we've been doing a lot of searching, buying, testing amplifiers. The DSP stuff is being tested and tweaked ATM. If it pans out to be good enough, we;ll add them to the cart. For the lazy browsers, we order the amps in, open them up, run a 7 step regimen, box them up and ship them. The Dash-V cases should be ready in the next 2 weeks. Not being an IT guy, my head's smoking right now. None of this stuff is intuitive at all. It takes quite a bit of work and email queries to get the job done right. I need some time off.
  16. Just because an amplifier utilizes protection circuitry that prevents catastrophic failure when driven into low impedance does not mean the amplifier is 2 ohm stable. The amp continually going into protection is the sure sign that it is unstable under those conditions and the cause should be immediately determined and remedied.
  17. Yes, the mystery of the untamed audio beast... the subwoofer bandwidth. Everyone wants the simple answer so that they can claim to have solved the mystery without the expense and the leg work. No, it isn't the sealed system.
  18. Regarding frequency response, I'm a musician first. As a bass player, I imagine a bass where each fret of each of the 4 strings has a different loudness. Into the trash can it would go. It's imperative that the dynamics come from the player and the overall level comes from the mixer. The frequency response of the instrument must be flat, meaning no hot spots and no dead spots. It's also equally important (to accuracy) that the in-room response be flat as well. In those respects, FR is everything. Regarding the tactile feel, you can attribute much of my system;s shake to the dual-opposed, up/down fining stacks in each corner. I can engage the 18 Hz HPF of the SEQSS and still feel the tactile response at the seats from 20 Hz through cross. That has little to do with being on a wood framed floor system, and that's a huge disparity in playback response. Brandon's rig is set up similar to mine in the front stage and, IMO, his system has plenty of tactile effect without the in-your-spine HST-18s. IMO, he not only doesn't need the nearfield 18s, they were actually a bit annoying to me, especially during music only playback, where they crossed the line between musical tones and completely non-musical massage tones.
  19. I agree with the philosophy and the down side of the XXXs. Well, you'll have mid bass like a volcano. That might make it difficult to run hot. Of course, you said at the GTG that you (like myself) prefer a much more balanced presentation than we heard at the GTG and at many demos by other members who seem to prefer the low end to run hot by 15dB or more. Looks like you'll just have to invite us over for a listening session.
  20. Here's Raptor with 3 boost SEQSS curves, HPF set to 'No':
  21. Check out Dave's Mariana in Josh's room:
  22. At the outset, I've never been a fan of the XXX drivers. Way too big, way too big a box requirement, way too much $$$. Looking more at the HST-18/UXL-18 is more my speed. There's not much difference as far as what EQ is required to get flat in your room. It's simple enough to project the HST-18, for example from anechoic to same placement of driver/mic you used to generate the in-room graph posted earlier: Done quickly, but I'm not gonna be too far off. A typical humped response (part inductance/part small box) is down around -7dB @ 20 Hz, whereas the low Q drivers are down more like -15dB @ 20 Hz. Pull down the hump of the long throw mid q driver or pull down the top end of the mega-motor low Q driver. A wash in the end, IMO. You're showing tons of room gain. Since the Fosgate is down -25dB from cross to 10 Hz
  23. It certainly looks cool but... As a candidate for HT, it's mounting depth is prohibitive and, as with any sub driver design, the higher the motor strength, the lower the Qts. It's Q is so low, it never achieves a 2nd order roll off. The HS-24 trounces it for 1/2 the price and has far less disparity between the bottom frequencies and cross. A quad of HST-18s in dual, dual-opposed boxes is a far better system for the same dough... Etc., etc.
  24. So, the Marantz stuff has analog inputs that would yield the following: If you input a left channel and a right channel into the stereo analog inputs, there is no output from the SW out jack? If you input 7 channels into the multichannel analog inputs, there is no output through the SW output jack?
  25. Sealed subwoofer performance is directly related to and completely dependent upon... AMPLIFICATION. I've built and operated more sealed subwoofer models in 3500 cubes over the past 15 years than anyone in this dimension of our solar system. I've used all of the QSC RMX models as well as the Crown XLS. I have the Marathon 5KW amp and the American Audio 6KW amp (100 pounds, 3RU big iron beast). I was the first AVS user of the Sanway LG copy amps and recommended them to notnyt. I've used 7KW, 9KW, 12KW and 14KW versions of that platform from a half dozen Chinese agents and manufacturers. I've tested various Class D amplifiers, with and without on board DSP, all of which have been rackmount amplifiers with commensurate cooling fans. The A Series amplifiers are the best value power for a sealed EQ'd subwoofer system I'm aware of. To our GTG, Nick brought a pair of HST-15s. Without signal shaping, they, like any other sealed subwoofer, perform well but nowhere near optimally. After dialing in a proper response using the Marchand Bassis, the in-room response was world class. We used an A-9K amplifier and played the cop car scene from HULK and progressively bumped the output power until we pushed the HST-15s to a measured 45 mm one-way throw. The measured output power was 8900 watts peak (the A-9K is rated to 9000 watts peak, bridged into a nominal 4 ohm load). The mains connection was a dedicated 120V-60Hz 30A outlet which technically will output 3600 watts continuously, but obviously peak voltage output of the A-9K on that outlet is a few decibels more. The 2x15" HST Raptor module required a +6dB low end boost in the signal to achieve the results we measured at the listening position. That means that if we run the sub at a nominal 2000 watts with content >20 Hz, we required 8000 watts for transients that include content <20 Hz, as the scene in HULK and many, many other scenes do. The HST-15 has a measured sensitivity of 85dB 1W/1M. A pair of them in a single box would yield 88dB 1W/1M. To see a peak result of 120dB at 1M would require 2000 watts input power. If you cut the power plant capability by -3dB, that would be a cruising power consumption of 1000 watts with full bandwidth peaks of 4ooo watts. That (4000 watts peak) is the minimum I would use. The A-5K would be perfect and have a dB or so headroom. You can eschew signal shaping and use a lesser amplifier but then I would recommend also buying lesser drivers and saving the money you would be wasting by applying crap power to world class drivers. That's why we call them Systems. The SP amplifiers are wonderful products from a great engineer through very cool dealers. They deliver the goods and are quiet in doing so. On the down side (every piece of hardware has one) they're butt-ugly, they're monoblock or dual bridged only and cost double the price. The rest of the choices mentioned will be the wrong choice for any system utilizing HST-class drivers and the Dayton stuff is for children under 10 years old. Just my opinion, FWIW, YMMV.
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