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#41
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On Thu, 24 Feb 2005 04:26:07 GMT, Joseph Oberlander
wrote: different design. Now, I would think that mounting small Maggies perpendicular to the side walls as satellites would be cool, since dipoles seem to work well as satellites. Of course, it would look a little weird, plus you might have to tinker with the angle and not have them 90 degrees from the wall. You'll get used to them quickly. They make them with off-white fabric. I would mount them so that the edges are directly facing your listening position(slightly off of 90 degrees from the wall) If I didn't think that it would impact the sound, I'd do some sort of slik-screen arty thing on the screens. Then they would cease being speakers and become a design component of the room. One thing that a lot of people don't consider is that you can do a similar thing with wall treatments as well. You can take a neat thick and rough fabric with a nice design and stretch it over a frame. I made such a 3 1/2 ft square hanging stretched fabric that worked well as a absorber that I would hang on the speakers' opposite wall. Sort of a mild LEDE arrangement. It seemed to make a slight difference, AND it looked like an expensive art piece, whereas it cost me about $5 for the wood and about $15 - 20 for the fabric. |
#42
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Joseph Oberlander wrote:
Ferstler posted the chart below: 31.5 Hz 20 Hz TN1220 113 dB 106 dB VTF-3 (20 Hz plug) 112 dB 100 dB VTF-2 (25 Hz plug) 106 dB 90 dB STF-1 103 dB 80 dB Velodyne F1800 114 dB 110 dB Velodyne HGS-15 110 dB 104 dB Velodyne FSR-12 104 dB 97 dB Paradigm Servo 15 112 dB 110 dB Nice chart - thanks This is but a small fraction of what I have on subwoofer max-ouput measurements. 20hz @ 80db just isn't going to compete with the five other speakers, IMO. I'd want 100db or better in order to handle movie effects with somewhat decent SPL. But, I guess I'm really into impact in movies. Well, Hsu makes no claims for the 20-Hz performance of the sub. It is essentially rated by him down to only 30 Hz. I did the 20-Hz measurement as a matter of policy. Actually, there are a number of bigger and/or more expensive subs out there that do worse. Sometimes considerably worse. Most movies do not have much bass energy below 30 Hz, although there are exceptions. The real expert on the dynamics of movie bass sound is Tom Nousaine. Tom helped to edit my third book (my second on AV), by the way. There are also quite a few other models I have measured, but these are ones that might interest you. I still like the VTF-3 for the price. It gets the job done and is a lot less expensive(and not a sluggish 15 incher) than the Velodynes. I have reviewed the HGS-15, as indicated above, and also reviewed the HGS-12 and several more conventional Velodyne models. Trust me, the Velodyne servo units are anything but "sluggish." Indeed, the fast-bass issue continues to mystify me, because a sub is designed to only handle frequencies below maybe 100 Hz (or lower, of course) and the device does not need to be "fast" to do that. The attack part of most low-bass signals will be handled by the midrange driver, anyway, with the sub (or woofers) just dealing with the tail attached to that attack transient. As for the need to taper off the bass "fast" and how some subs cannot do that, well, most musical bass from acoustic instruments are not particularly fast when it comes to the taper off, anyway. Most subs seem sluggish, because they have a substantial amount of harmonic distortion that makes them sound bloated, or possibly the higher harmonics generated makes the signals sound not quite so full, rich, or low. If the distortion harmonics are high enough, they will also have an impact on sub localization. Ironically, in some cases a sub sounds slow, because the listening room allows a standing wave to pile up at the listening position. Movies, well, certainly some bass transients might taper off fast, but the attack transients will again be handled by the midrange drivers in the satellites. That is how the Franssen Effect allows for those satellites to make it sound like the bass is coming from them and not the sub. Well, the precedence effect can also play a part, and long wavelengths tend to not be directional, anyway, even when heard in isolation without attack-transient clues. In a head to head music face off, I doubt if anyone could hear the difference between the VTF-2 and a Velodyne servo FSR-12. See my comments on Velodyne $1000+ for a sub is silly. While the FSR-12 and VTF-2 sound really similar down to 25 Hz (certainly with music and even with test tones to a degree), below that frequency the Velodyne pulls away. With test tones you can slightly hear differences at just about any bass frequency below about 40 Hz when comparing a servo Velodyne to any other good sub that is not servo controlled. With music and movie material this really does not matter much, but some people like the idea of really low distortion. I certainly would not want to give up the F1800RII in my main system, but if it went belly up I would probably replace it with a Hsu or SVS model. Still, the latest super Velodyne (digital drive) models have built in equalization to help smooth out room resonances. A good idea. Of course, a very fine performing SVS 20-39PC Ultra I recently reviewed in The Sensible Sound had an on-board parametric equalizer that could null out any single peak between 20 and 80 Hz. (One would need to be careful doing this, needless to say.) Not bad for a unit in the price category you noted. However, I think that the Velodyne models that have on-board equalization also include a microphone to help the user get the best results. So go the subwoofer wars. Howard Ferstler |
#43
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Joseph Oberlander wrote:
Howard Ferstler wrote: Room size should not have an impact on bass directional clues. You could tell if the sub was quite close to the listener, but that is only the case if it is either generating harmonics that would be high enough in frequency to provide localization clues or if artifacts (knick knacks, lamps etc.) close to the sub were vibrating in sympathy. IIRC, the O.P. said he had a huge room, so beyond 30 ft long, or so, 50-60hz or so is still directional. The systems also probably had the crossover improperly adjusted(and/or bad positioning), and were getting the overamped "boomy" effect. The best way to see if bass is directional is to disconnect the satellites and play some bass-strong recordings. See if the location of the sub can be pinpointed with a variety of crossover points when at the primary listening position. At higher frequencies (100 Hz, say) it might be possible, but in some cases the reason is that the sub is generating harmonics (at 200 Hz or higher with a 100-Hz primary input) that would make localization possible. This is one rationale for the Velodyne servo approach, which reduces such harmonic artifacts to inaudibility. Of course, as I noted elsewhere, if the sub is near some kind of item in the room (figurines on shelves, a lamp or lamp shade) the resonance of that item would also provide localization clues. Lamps sitting on subs can cause problems like that. However, even if slight localization clues are possible, in most cases, once the satellites are reconnected the Franssen Effect or the precedence effect will render them inaudible. Howard Ferstler |
#44
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On Fri, 25 Feb 2005 12:51:05 -0500, Howard Ferstler wrote:
Joseph Oberlander wrote: Howard Ferstler wrote: Room size should not have an impact on bass directional clues. You could tell if the sub was quite close to the listener, but that is only the case if it is either generating harmonics that would be high enough in frequency to provide localization clues or if artifacts (knick knacks, lamps etc.) close to the sub were vibrating in sympathy. IIRC, the O.P. said he had a huge room, so beyond 30 ft long, or so, 50-60hz or so is still directional. The systems also probably had the crossover improperly adjusted(and/or bad positioning), and were getting the overamped "boomy" effect. The best way to see if bass is directional is to disconnect the satellites and play some bass-strong recordings. See if the location of the sub can be pinpointed with a variety of crossover points when at the primary listening position. That's a *terrible* way. All you'll accomplish is being able to locate the harmonics of the sub -- it's distortion components. The way to test if bass is direction is just listen to the damn thing, setup the way it is designed. Listen to some music (you do remember what music is, right?), preferable some chamber music with a single bass player. See if all the bass seems to be coming from where you hear the bass player. duh. |
#45
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TCS wrote:
On Fri, 25 Feb 2005 12:51:05 -0500, Howard Ferstler wrote: The best way to see if bass is directional is to disconnect the satellites and play some bass-strong recordings. See if the location of the sub can be pinpointed with a variety of crossover points when at the primary listening position. That's a *terrible* way. All you'll accomplish is being able to locate the harmonics of the sub -- it's distortion components. The way to test if bass is direction is just listen to the damn thing, setup the way it is designed. Listen to some music (you do remember what music is, right?), preferable some chamber music with a single bass player. See if all the bass seems to be coming from where you hear the bass player. duh. Right. However, doing it with the satellites disconnected will greatly highlight any directional information the sub might be generating, because there will be no satellite signals masking the low-range soundfield. If you cannot hear the sub's location with the satellites not operating you certainly will not hear it when they are in operation. Incidentally, Nico Franssen (whom I biographically profiled in the second edition of The Encyclopedia of Recorded Sound) proved that way back in the 1960s. With the satellites reconnected, the precedence effect (assuming the sub is further from the listener than the satellites, which is often the case), will make the location-related masking even more effective. It is also in the very nature of long wavelengths for the source to be difficult to locate. Regarding those long wavelengths, harmonic overtones generated by a subwoofer and riding on the fundamentals (or artifacts sitting close to the sub and vibrating sympathetically) most definitely can generate location clues that would be mistaken for directional clues in the low bass. This is one reason that setting a lamp or some other hard object on top of a sub can cause problems, and it is also one reason why one should try to purchase a sub that has very low harmonic distortion. In any case, my guess is that what you think you are hearing involves the fact that you *know* that the sub is "over there" and generating sound. Regarding music listening, I have published two books of record reviews (one published by McFarland and the other published by A-R Editions) and have reviewed hundreds of recordings for The Sensible Sound. How many have you reviewed? Howard Ferstler |
#46
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On Sun, 27 Feb 2005 14:56:59 -0500, Howard Ferstler wrote:
TCS wrote: On Fri, 25 Feb 2005 12:51:05 -0500, Howard Ferstler wrote: The best way to see if bass is directional is to disconnect the satellites and play some bass-strong recordings. See if the location of the sub can be pinpointed with a variety of crossover points when at the primary listening position. That's a *terrible* way. All you'll accomplish is being able to locate the harmonics of the sub -- it's distortion components. The way to test if bass is direction is just listen to the damn thing, setup the way it is designed. Listen to some music (you do remember what music is, right?), preferable some chamber music with a single bass player. See if all the bass seems to be coming from where you hear the bass player. duh. Right. However, doing it with the satellites disconnected will greatly highlight any directional information the sub might be generating, because there will be no satellite All it'll do is let you hear what would be otherwise masked. signals masking the low-range soundfield. If you cannot hear the sub's location with the satellites not operating you certainly will not hear it when they are in operation. And if you can hear the sub's location then you've learned nothing and certainly nothing about what the best crossover frequency is. Incidentally, Nico Franssen (whom I biographically profiled in the second edition of The Encyclopedia of Recorded Sound) proved that way back in the 1960s. With the satellites reconnected, the precedence effect (assuming the sub is further from the listener than the satellites, which is often the case), will make the location-related masking even more effective. It is also in the very nature of long wavelengths for the source to be difficult to locate. Regarding those long wavelengths, harmonic overtones generated by a subwoofer and riding on the fundamentals (or artifacts sitting close to the sub and vibrating sympathetically) most definitely can generate location clues that would be mistaken for directional clues in the low bass. This is one reason that setting a lamp or some other hard object on top of a sub can cause problems, and it is also one reason why one should try to purchase a sub that has very low harmonic distortion. In any case, my guess is that what you think you are hearing involves the fact that you *know* that the sub is "over there" and generating sound. Regarding music listening, I have published two books of record reviews (one published by McFarland and the other published by A-R Editions) and have reviewed hundreds of recordings for The Sensible Sound. How many have you reviewed? Howard Ferstler |
#47
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TCS wrote:
On Sun, 27 Feb 2005 14:56:59 -0500, Howard Ferstler wrote: Right. However, doing it with the satellites disconnected will greatly highlight any directional information the sub might be generating, because there will be no satellite All it'll do is let you hear what would be otherwise masked. Right. It basically is the acid test for localizing a subwoofer. It works far more effectively than trying to do it with the satellites hooked up. signals masking the low-range soundfield. If you cannot hear the sub's location with the satellites not operating you certainly will not hear it when they are in operation. And if you can hear the sub's location then you've learned nothing and certainly nothing about what the best crossover frequency is. Of course. However, you then work downward with those crossover frequencies and find a point where the directional clues disappear. Of course, if the sub is generating spurious harmonics, it may not be possible to ever go low enough. The harmonics will always make the sub's location detectable. In any case, I have found that 90 Hz, provided the sub is low-pass filtered at 24 dB per octave and is not generating audible harmonics, will work just fine. The THX people probably would agree, but they decided to work at 80 Hz, just to make sure. Once you get down below about 70 Hz, you begin to run the risk of the spaced satellite woofer systems (particularly the left and right mains) generating suckout artifacts between them that will cause unwanted nulls. Those quarter-wavelength cancellations can produce the same havoc as boundary-related suckout cancellations. One advantage of any sub/sat configuration (aside from obvious soundstaging advantages with the satellites and the ability of good subwoofers to go lower than most full-range systems) is that some of the bass suckout artifacts we get with paired speakers playing full-bandwidth down into the low bass will have some of those in the 50-70 Hz range eliminated. Howard Ferstler |
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