Anyone else excited for this Borresen subwoofer?!!!
It seems quite unique...(as one might expect from Michael B).
Borresen Subwoofer - Michael Borresen Interview
"Subwoofer speed"? Can't wait to see the speed o meter measurements. Their design reminds me of a small version of the Danley Labs Matterhorn semi truck trailer subwoofer project they made some time ago. https://www.youtube.com/watch?v=o36Kp6veJ6c Their middle of the room positioning suggest -6dB sub-bass speakers? Sensibly priced low frequency innovation is always welcome. All the best to the folks at Borresen.
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The DSL Matterhorn, as per the video, is actually a very large tapped horn which means both sides of the woofer cones are used for pressurization, so that the back wave of the cones build up down through the expanding horn path to the bottom of the container, and from there the horn path goes into a 180 degree turn to continue back towards to the container opening where the combined wave from both sides synchronizes with the front wave of the woofers at the "mouth." This is not what the Borresen sub is doing (i.e.: it only uses the front wave of the cone, added to the fact that it’s not horn-loaded), and the "velocity" rethorics to me reads more into merely creating a combined pressurization through the slot at the front. Lot of yada yada and hifi sensationalism if you ask me, but I actually like the approach being the multitude of smaller woofers will combine and act like a single, larger woofer, which to me is preferred route vs. several smaller, and spread out woofers. |
It is a copy of the Sonos subwoofer and its very low end response below 30Hz will be limited although digital signal processing can improve this a little. The person speaking made one large mistake. He called the speaker a dipole. It is not a dipole, it is a bipole. With dipoles the rear wave is 180 degrees out of phase with the front wave. with Bipoles the rear wave is in phase with the front wave. Slot loading the drivers can produce impressive results. The problem with these enclosures is the four large side panels and the top and bottom will be difficult to control and will tend to resonate. It is certainly a design worth listening to. Like any subwoofer a 2 way crossover is required. I do not like smaller drivers trying to make low bass. They tend to have higher resonance frequencies which cuts off their response below and they are not in any way "faster" than larger drivers that do not have to work nearly as hard producing very low frequencies. The smaller driver tends to have higher distortion levels. There is no replacement for displacement. Subwoofers never fair better in the middle of the room. This is where their efficiency is lowest. Up against a wall you get 3dB better efficiency. In a corner 6dB better. This means lower levels of distortion. Some will say this increases room interaction, not if you use two or more subwoofers. If you form a line array with subwoofers you can minimize room interaction. My own feelings about the subject are here https://imgur.com/user/mijostyn/posts |
@deep_333 Not at all! Many units out there give you the ability to adjust delay. The Aussies call it launch time. These include units by DEQX, Anthem, MiniDSP and Trinnov. It is an absolute necessity for sub integration. |
@mijostyn Are all your sources digitized? @phusis I had one of Tom's tinnitus inducing Tech 7 ServoDrive belt drive horns with the band for a few weeks. Brought it in the house and ran the source through the Velodyne's Rap EQ preset, OMG! I hate to criticize anything I haven't actually listened to at home or at least on a familiar system. On the other hand there were some phrases coming from Mr. Borresen that triggered my yada whada? too. As a Double Bassist a single or 6 pack of -6dB sub-bass systems just don't go low. |
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Correction: presumably I was incorrect about the Borresen sub principle and it only utilizing the front wave of the woofer cones. They look to be mounted in a folded-baffle design (a so-called "RiPol" after Alex Ridtahler, short for Ridtahler Dipole) that radiates both front and aft in a directional pattern - i.e.: the backside of the cones "shoot" into the open-to-the-back dual chambers - and thus necessitates a free-standing position. Inherently low efficient, but by all accounts (very much dependent it seems on accurate positioning) delivering a very clean "coming from nowhere" bass, also very suitable it appears in conjunction with planar/ESL main speakers. Interesting principle for a number of reasons, but less so for my requirements in particular. Sorry about the confusion. @deep_333 wrote:
The buzzwords here are "purist hifi" and "analog," but as poster @mijostyn points to delay can be done in the digital domain (the non-purist approach, god forbid), even more accurately and expansively with a separate, quality DSP unit that can also be more sonically transparent than most analog solutions (not least omitting the passive crossover), and if the same DSP section affects the whole frequency range actively the inherent delay of the unit affects the different driver sections equally. What’s considered "purist" in the Borresen way or general sense of audiophilia is usually only so in a limited context (i.e.: analog vs. digital), and so I’ll glad incorporate quality digital where it makes a lot of sense, apply a purist oriented approach elsewhere and try and see the forest for the trees more clearly. @m-db wrote:
I read of those, allegedly they were SPL-beast (and then some) but according to sources also somewhat unreliable?
Good point.
Yeah, the sub principle at hand at its core certainly isn’t unique, it appears, though hardly widespread in use either. I’ve heard similar rhetorics from Borresen and others with more or less grandstanding notions, and yet the physical framework where speakers go, as usual, is stunted. One can only do so much from a restricted outset.
Perhaps a physically more all-out open baffle tower sub system would be the way to go (multiple 12" woofers or bigger), albeit taking up more space into the heights and without being SPL- or extension-monsters all the same.. |
@m-db Yes, every last one. The phono stage is run balanced into a Lynx Hilo, a studio ADC/DAC/switcher/digital gain controller type thing. The Hilo is then connected to a DEQX Pre8 by an AES EBU cable. The DEQX is a new digital processor/preamp with a 4 way digital crossover, bass management, parametric EQ, room control and streaming via a Volumio processor. I use Qobuz. @phusis If you want accurate bass open baffle subwoofers are the last thing you want to do. You do need multiple drivers to get anywhere, but in a sealed system preferable arrayed as a line source. Line sources project power and minimize room interaction. The problem as always with subwoofers is putting the drivers into enclosures that are not musical instruments. |
The Rythmik Audio plate amps include a ’Delay/Phase" control, providing continuously-variable adjustment of from zero milliseconds delay / zero degrees phase rotation up to 16 milliseconds delay / 180 degrees phase rotation. Such a control makes aligning a sub with a loudspeaker far easier than moving the sub physically. Increasing the amount of time delay / phase rotation does exactly the same thing as does physically moving the sub further away from the loudspeaker. So you can find a good location for a sub in terms of room modes, then use the delay/phase control to align the outputs of the sub and loudspeaker.
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@mijostyn , Most of these brands you cited are used by the multichannel guys and the ones who tinker with pro hardware primarily (no stranger to those). I was referring to more purist brands like, say..Esoteric, D’Agostino, Denafrips, Luxman, Schiit, etc who have a inability to provide an independent channel delay on their dacs/linestage or whatever... to delay any channel by how much ever the hell i want. They are so pure that everything will get executed magically for the guys who bought it apparently. |
@m-db For example, a servo controlled driver will be forced to slam STOP quicker than some floppy/sloppy driver. It will result in the perception of FAST BASS! There may be other ways to do it as well. What is so hard about this to comprehend? |
@deep_333 What you just stated to @m-db is marketing hyperbole without any basis in reality. The right term is powerful bass. Powerful bass requires the ability to move a large volume of air in a controlled fashion. This generally means large or multiple drivers with powerful amplifiers that have extremely low output impedances. Most importantly it takes enclosures that do not resonate, rattle or shake. Servo drives are an excuse for poor and undersized drivers in crappy enclosures. Digital Room control and EQ are far more important features for bass management. Next, all of the brands I mentioned also make 4 channel preamps for stereo systems, 2 main speakers and 2 subwoofers. DEQX only makes preamps for stereo systems. All those brands you mentioned do not have the engineering capability to pull off preamps like the DEQX Pre8, the Trinnov Amethyst, the Anthem STR and the MiniDSP SHD series. Digital Bass Management is critical for adequate subwoofer performance. Without it you are living in the stone age. |
Borrensen is, and correct me if I'm wrong. the Rolex of hifi the biggest difference being Rolex keeps time while letting everyone know you've got money to burn. The company offers no reason to think they are better equipped to build subs than the co's already vested in providing sub bass solutions, likely for a fraction of the cost. |
@mijostyn , I think the nay saying is propagated by some competitor brands who are disgruntled because they can't step over a patent (making you all believe it's mostly marketing hyperbole). In the world of control systems, there is something called a free lunch. In this audio world, it could compensate for a poor driver/enclosure design. But, if the latter is not compromised, it can rise above the rest. Call Rythmik's founder (he's a EE) and have a nerd talk with him. He'll put the EE slant on it and describe it to you. Get this book off amazon if you would like to read a bit. If it looks like hieroglyphics from time to time, it could mean that you are missing some pre-requisite.
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@deep_333 I am deep into control systems. I have been using room control and digital bass management since 1996 not to mention I design and build my own subwoofers. One of today's excellent low distortion subwoofer drivers 12" and larger, used in adequate quantities for the environment have no need for servo anything. |
Paul McGowan of PS Audio on dismissing servo-feedback in his custom upgraded IRS V bass towers: https://youtu.be/1OdkRiwmYbE?t=101 Subwoofers from the outset of what are actually physically accommodating designs is the purist approach audiophiles don't want or know how to talk about, because it's inconvenient from the perspective of interior decoration and spousal approval, i.e.: the sheer size of such designs, as well as an area relegated to lesser importance - also in regards to the use of amplifiers and DSP section. What's so hard to comprehend about that? |
@mijostyn Get the highest quality low distortion driver you want...It is still unrelated to the principles behind servo control. You are still asking an accelerated mass to stop passively/ring down without it, which may be good enough with a high quality driver. You are actively stopping it with servo control by letting it constantly track a setpoint. @phusis Paul’s vid describes the free lunch that he got with initial use of crappy drivers. How about this....Get the low distortion high excursion bells and whistles driver. Now, stack/integrate several of them so they don’t have to move as much for said spl level. Now, add servo control on top of it...it is incremental. It could all be overkill at normal listening levels, but, maybe not, because it is still the highest distortion component in the chain, relatively speaking. On a related note, I have some coupled cavity speakers, i.e. the physical bass drivers sit inside and are cavity coupled to external radiators (Acoustic filter/ clean bass). One might argue that it is a unnecessarily complicated design. But, the free-er lunch there was that you didn’t need very expensive drivers trying to hit a price point (the expensive driver that may or may not hit a performance requirement just because you kept spending up the wrong tree). I know because i also owned a cost no object conventional speaker design from that same designer...a few different ways to do these things/clean it up, i suppose.
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@deep_333 You are not understanding the physics of the situation deep. A powerful amp with a very low output impedance completely controls to motion of a well designed subwoofer driver. Music (sound) is not a series of stop and go traffic lights. It is a conglomeration of sine waves. As soon as the cone passes the equilibrium point it starts decelerating gradually until it passes the zenith then it accelerates toward the equilibrium point again. The cone never stops, it just changes direction all under control of the amplifier and powerful magnets. Subwoofers do need help in other areas to provide that "you are there" intensity of a live performance, but servo control is not one of them. I owned a pair of Velodynes once. One of them is serving as a base for a fish tank. |
@mijostyn , We can actually obtain high fidelity measurements (track the driver) and compare with instrumentation used typically in other fields of engg ....how well it was controlled or not....any driver+amp or a servo based system (LVDT, or a series of high sensitivity mini accels, conditioners and a DAQuisition system). Until then, you could never be sure... |
Oops, I didn't mean to criticize the ability of servo control rather the basic premise of the term subwoofer speed. I write poorly, my bad. "sloppy / floppy" that I'm going to use, thanks.
I replaced the Octavium with my first servo sub in the late 70's from Jonas Miller and Ken Kreisel at their Wilshire Blvd store. They had a stunning with and without demonstration setup there. Now that I understood I was listening for I heard an even better presentation when I brought home Velodyne's ULD servo design and currently use two DD Plus. That David Hall, smart guy. I believe the sub in my large Bag End ELF-M / S18E-D Bass rig has some control associated. |
@deep_333 wrote:
It’s interesting to note that, with the knowledge and experience of being a servo-feedback designer himself (for the bass system of the IRS V’s), Paul is expressing how "everything is a compromise," and that - it follows - includes the servo-feedback circuit itself. What’s entailed in this specifically isn’t made clear, but it touches upon the aspect of a more purist oriented approach where, with a physically more all-out sub system, one can avoid "compensating measures" like servo-feedback, EQ-boosting and other. With the scenario you’re suggesting (i.e.: low distortion high excursion bells and whistles driver in stacks) the need for servo-feedback circuit will by all accounts be lessened, and so when will the insertion of such a circuit itself be deemed a larger, negative influence than the positive ditto it’s supposed to create? From my chair it appears that what Paul implies is that this is the very reason for them having omitted servo-feedback in their driver and amp upgraded sub towers, because servo-feedback wouldn’t have the desired, positive effect here when all is said and done. As to the negatives of larger subs and the compromises that may or may not be involved here, structural integrity/enclosure resonances is the one area that is usually addressed. The important question to ask then, to me at least, would be to which degree subwoofer enclosure resonances of a certain magnitude would be an actual impediment in the reproduction of music, not least compared to the contribution of mechanical noise/distortion coming from smaller, direct radiating and inefficient woofers working much harder; would you rather have a capacity strained* small sub setup with more or less inert enclosures, or a capacity unlimited, larger ditto with what is still structurally sound cabs (i.e.: built with interlocked, CNC-machined and Baltic Birch multi-layer plywood, and heavily braced)? From experience I can say with absolute certainty that, in each and every case, I would choose (and have chosen) the latter option. It’s no contest, period. How many have actually made an informed decision based on experience with both options? Close to none, because the by far most common scenario is that few even considers large, efficient subs for reasons we know all too well, and thus the only frame of reference to go by for most is that of smaller, inefficient subs.
My quip would be: there’s no free lunch with smaller sub designs. The good thing working with large, efficient sub designs is that of being dictated design appropriate woofers. Either you use them, or performance will be severely impacted (and who’d want that?) - that’s the deal. With tapped horns, like I use, there are very specific woofer requirements and a relative small specs-"window" to accommodate, or else the design won’t perform as intended. Like, too little motor/magnet force and the horn isn’t properly resonated; too much and the air pressure will be too compressed at the throat section and thus also not resonate the horn properly. Too light and non-rigid a cone is an issue as well, also because a cone too flimsy would simply be ripped to pieces with the uneven pressure built-up at the front side of the cone in the throat of such a design. Build and board material quality is also important here. When the woofer cone really starts moving in tapped horns (and it takes a lot in domestic milieus) the pressure built-up inside the horn path can be so severe that the enclosure cracks open due to the immenses air pressure forces created inside (remember: the single 15" woofer per cab of my tapped horns is force multiplied at the mouth into the equivalent of two 18" direct radiating woofers). In reality such sub designs are built to withstand SPL’s at full tilt, why they’re rigidly built for that very reason - i.e.: design dictated. *When are subs capacity strained? When there’s not enough if any notable headroom to speak of at the max. SPL one desires. What’s sufficient headroom? From my chair, no less than 10-15dB’s, preferably +20dB’s. |
@deep_333 In many rooms you don't need it, owing to the fact that the best way to do subs is with multiple subs so as to break up standing waves in the room. Below 80Hz in most rooms (unless they are very large) the bass has bounced all over the room before your ear can sort out what the bass note actually is. This is because at 80Hz the wavelength is 14 feet. So its had time to bounce off the wall behind you and pass by you again before your ear can even tell the note. If the note is cancelling the incoming bass note when it bounces, that is called a Standing Wave and no amount of EQ can fix it because the power you put into that result gets cancelled- you simply eat up amplifier power. That is why multiple subs works so well- because if placed asymmetrically, they can break up standing waves so you get evenly distributed bass at the listening position as well as everywhere in the room. So a time delay doesn't win you a whole lot in this situation. Audiokinesis has a sub called the Swarm which is 4 subs each using a 10" driver. Because 4 subs might seem a lot to many people, they are designed to sit against wall to take advantage of the room boundary effect @mijostyn mentioned earlier. The subs are designed to roll off at 3dB/octave starting at 100Hz to compensate. This allows them to be flat to 20Hz in a compact package (1' square, 2' high). Because there are four 10" drivers, they don't need to have to have a lot of excursion unless the room is quite large. Because they are meant to be placed against the wall, they tend to be more innocuous; very easy to live with, not just in terms of space but also very easy to integrate into a system!
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@phusis and @atmasphere are making a lot of sense here. Most of the distortion created by subwoofers is not coming from their drivers, but from their enclosures, the room and poor integration. Using large and or multiple drivers that have well designed, well ventilated motors is the best way to eliminate distortion on the part of the drivers by minimizing excursions, keeping the driver's suspension well within its linear zone. After that it is all about enclosure design and construction, the layout of the room, the use of multiple units against walls and in corners and proper (digital) bass management. It is difficult to determine what crossover and slope are going to sound best in any given system. It is a trial and error process. You have to have an assortment of choices to find the right solution. This is next to impossible in the analog domain and no problem in the digital domain. In my current setup I tried 5 different solutions before finding the right one, 120Hz @ 84 dB/oct. both high and low pass filters. 120Hz works for me because the subs I use are clean up to 200Hz, they are stereo, taking 120Hz and under away from my main speakers, full range ESLs, cleans them up dramatically and increases headroom by at least 10dB. I get away with it because I can utilize a very steep digital filters which keeps the subs out of the midrange. I did not know this was going to work until I tried it. There are multiple methods to integrate subwoofers. Most of them I would characterize as unfortunate. Subwoofers still have a terrible reputation in some circles because of this problem. Using analog bass management, it is easier to make a system sound worse with subwoofers than better. |
OK thx was watching the YT videos about the Borenson subs and learning
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@quickjack1234 Check out Magico's Titan subwoofer, then check out Martin Logan's Balanced Force 212 and 210. These three are the best commercial subs out there. They all still need a proper active crossover. |
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oh i agree we should use all the control we can/ want to NO reason not to! audioholics talked about delay in that 1 hr + YT video but i bet the dual gr open baffle servo sub DIY flat pack kit @ $1.7 K is just as good or better. i am watching/ watched all these. |
