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Author Topic: Altec 802 and power handling math session Michael Schaffer "Where is the Boardwalk Hotel?" Posts: 4143 From: Boston, MA Registered: Apr 2002 posted 12-16-2002 09:51 PM                        Actually I just wanted to point to the articles on John`s website which are very good reading and some of them address the same subject that Steve wrote about, I didn`t want to set you people to fight each other again! I noticed from earlier topics that there seem to be some enmities and emotionally laden subjects. But since it happened now, I can`t resist saying that the HPS-4000 systems that I have heard are BY FAR the best cinema sound systems I have heard yet. On this subject, my opinion weighs very heavily because I am also a professionally trained classical musician. Maybe there are better ones somewhere, but I haven`t found them yet.  |  IP: Logged John F. Allen Film Handler Posts: 54 From: Newton, MA Registered: Nov 1999 posted 12-17-2002 12:12 AM                     Well, here we go I guess. Please believe me when I say that I had not intended to add anything more to this thread -- a thread that started with a most intriguing and learned discussion of Altec drivers. However, Steve Kraus raises a question that I have tried to answer before but was stopped. At the risk of being a bit long winded, I would like to answer. First, however, I have to say that Mark's experiences and his opinions of the installations we worked on together in the 80s, are his, and do not reflect the findings of virtually everyone else I have worked with. Nor are they consistent with the continued success of my business -- a business that has allowed me to accumulate over 1.2 million miles flying all over the place doing what I'd do for free if I could. But, I also need to say that I do agree (to a point) with some of his comments. As Mark points out, things have evolved since the 80's. We have improved every aspect of our loudspeaker designs and their construction techniques. The smoothness of the woofers has certainly been improved. So has the way my systems are tuned. The other thing that has improved, perhaps even more than my speaker systems, are the power amplifiers that BGW builds especially for the HPS-4000® sound systems. In fact, we are now working on the next generation of amplifiers that, incredible as it is, sound even better than the Millennium 3-HPS® units that we are using today. How they keep doing it, I don't know. As for Steve's question regarding my setup methods, the short answer is yes, anyone with good ears and some training could do what I do. Also, yes, there is a way to measure what's going on. I use a measurement technique that is far far better at "measuring" what we need to know than the steady state pink noise based methods that remain the standard in this industry. However, it is still limited in its accuracy, particularly in the mid bass region. In fact, I have yet to see a measurement method that is really usable in these frequencies. It remains as true as ever that there is no system available that can measure what something sounds like. As Don and Carolyn Davis have always insisted, it is the "analyzer between the ears that is most important." Therefore, my methods have gone beyond mere measurements and knob turning because they have had to. My good fortune is that I have "calibrated my ears" in Boston's Symphony Hall listening to live music. The Boston Hall, as I have verified by listening to other halls all over the world, is the best I have heard. It is the hall every acoustical consultant hopes to duplicate and every orchestra loves to play in. I would add that earlier this year, I discovered the incredible Konzerthaus in Berlin that sounds as beautiful, though, being smaller, cannot sound as big as the Boston hall. By being so totally familiar with Symphony Hall and its sound, a sound that reaches the greatest potential available in symphonic music, I can bring this knowledge and experience to my work in motion picture auditoriums. Anyone with such a background will have a distinct advantage when attempting to build sound systems to reproduce recorded music as well as movie soundtracks. It is also with this experience that I have learned that direct radiator woofers cannot reproduce music. Neither, for that matter, can horn loaded woofers, nor can any loudspeaker. However, a well designed horn -- and there are few -- comes the closest. As many may know, I serve as the sound director for the Boston Ballet. The Boston Ballet is a live company. There is a live symphony orchestra playing in a large pit that was actually designed by the Ballet's music director Jonathan McPhee. The only reason they need a sound director is that the theatre's acoustics do not provide a way to direct sufficient sound into the main floor areas under the balcony. The theatre is huge, with some 3800 seats and a balcony that bisects the rear two-thirds of the room. I have designed and setup a nine channel method of not only directing the sound into the weak areas, but also reinforcing the acoustics of the room to create a more concert hall environment and effect -- all while maintaining the auditory perspective of the orchestra throughout the theatre. What we have then, is a sound system that coexists with a live symphony orchestra. If there is a more demanding challenge in this profession, I don't know what it could possibly be. The pit and sound system have proven so successful that both Jonathan and I were virtually commanded to appear at a special symposium convened at MIT by the Acoustical Society of America, honoring the centennial of Wallace Sabine. We had a standing room only crowd from around the world, lots of questions and even one virtual confrontation. However, the conference chairman and others who had heard the results of our work stood behind us. There are many reasons why the audience doesn't know that the system is on, but one of the most important is that the horn loaded woofers don't color the bass the way direct radiators do. Not only do horns have an advantage with much larger radiating areas, the benefits in the way horns couple to the room, the amount of air they move, their inherently lower distortion and the shape of the planer waves they produce cannot be found with direct radiator systems in anywhere near the same space. Furthermore, to suggest that our horn loaded woofers can't do much below 60 Hz is pure baloney. Getting back to tuning: One of the problems we face in the absence of a competent measuring system, is the tone of speech when played through sound systems. Because the mid bass region is so critical to this tone, and since this region remains the most impossible to measure, I do listen with known reference materials. I do make adjustments as required to achieve natural tone. This must be done. Typically these adjustments are in the one or two dB range. Until I began doing this, I found that too many of my systems could sound heavy in these frequencies, and could even create the "honky" sound mentioned by Mark that movie theatre systems are still so famous for. Happily, this problem has been solved for a long time. Finding the best reference materials took years. This is one of the reasons the SMPTE review noted the dramatic improvement in clarity and presence. But the review also said that the audience could hear elements in the sound with the HPS® tuning that were not present when listening to the results of industry-standard tuning methods. This is no joke and should not be ignored. John F. Allen PS: Thanks Michael!  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 12-17-2002 12:17 AM                     John said"Indeed the SMPTE review of one such demonstration said "John explained and audibly demonstrated why these conventional formulae [tuning methods] may be flawed, resulting in unreliable and unnatural acoustic results. Several 2-3 minute scenes from recently released popular movies were screened, each with the system tuned to various industry-standard configurations. The final screening for each segment was tuned using John Allen's approach, yielding dramatic improvement in audible clarity, bass response and presence. In most cases, the audience heard sound elements such as birds, wind or rain which had not been discernible in the previous screenings. Audience reaction to this demonstration was enthusiastic." If memory serves me correct that was a section review not a statment endorsed by any enginering comitee or the board of governors of SMPTE The SMPTE standard still recomends a minimum of 4 mics placed in the reverberant field of the room in question not in the near field. This is still the standard endorsed by almost every equipment manufacturer and studio recording factility  |  IP: Logged Michael Schaffer "Where is the Boardwalk Hotel?" Posts: 4143 From: Boston, MA Registered: Apr 2002 posted 12-17-2002 03:19 AM                        You are right Gordon, and that practice should also be generally adhered to since very few people even have the ability to fine-tune a sound system by ear. It takes a very, very long time and a lot of practice to learn to hear analytically and the vast majority of people simply can not hear well enough. However, if somebody has cultivated that ability then coupled with a technical understanding of a given system it can be a very satisfying method.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 12-17-2002 08:37 AM                     John, Air miles hardly translate into how someone feels about how anything sounds, or how well a buisness is doing or not, but if ya want to know about air miles just ask any THX Technician, and many independent techs like Gord, or Richard. I think they blew right past you on the last flight. I'm fortunate enough to have left the airlines behind after traveling on them for many years so directors could watch their film at their location. I now drive around the mountain states servicing theatres and enjoying the incredible scenery and the wonderful people that live around here. As far as your customers liking your systems that is good. They bought them because they like them and the sound. But I will bring up a major point here again in that what if something happened to John, or his hearing. Who would tune his systems? Kindest regards, Mark  |  IP: Logged Michael Schaffer "Where is the Boardwalk Hotel?" Posts: 4143 From: Boston, MA Registered: Apr 2002 posted 12-17-2002 10:49 AM                        People who have the advanced hearing ability I described above. For instance, a really good recording engineer or a well-trained musician. It may be difficult to imagine, but it is actually possible to learn to hear so precisely that sound has a very defined "shape" and characteristics which are evident to the trained ear. But as I said, it takes a very long time and a lot of practice to obtain that ability. But this kind of fine-tuning is something good musicians do every day when they play. It is one of the reasons why specific symphony orchestras have a particularly good sound.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 12-17-2002 02:38 PM                     Michael, You hit the nail on the head and have only reinforced what I said. After talking to three Academy Award winning lead mixers at Todd-AO who have VERY golden ears, plus what I hear with my own ears thats why I went the route of direct radiators. That is what the films are mixed with these days and its the only way to hear what the Director intended. These and all other "Golden Eared" mixers are using Direct radiator systems of one sort or another. There was and may still be a stage at Goldwyn that was set up with Klipsch stuff but not sure if that is still there or not. John could confirm this one way or the other though. Mark  |  IP: Logged Scott Norwood Film God Posts: 8146 From: Boston, MA. USA (1774.21 miles northeast of Dallas) Registered: Jun 99 posted 12-17-2002 03:05 PM                        On the topic of the subjective nature of sound quality: does anyone know what equipment was in place at the Cinerama Dome in LA as of January, 2000 (pre-renovation)? This was by far the best sounding (to my ears) movie theatre I have ever heard, which is especially impressive considering the odd shape of the auditorium (I was sitting dead center in the front section). Picture quality there was sorely lacking, but the sound blew me away. Oddly, the THX-certified Chinese theatre nearby (also pre-renovation) had one of the worst-sounding systems I've heard. The Uptown in DC is probably my second-favorite theatre for sound quality, but it's not quite in the same league as the Cinerama Dome.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 12-17-2002 06:48 PM                     Don't know what was in there but years ago I saw Rodger Rannit there and it was amazing to say the least. The original Chineese never had good sound, thats one of the reasons they had the chineese 2 and 3 next door. They were excellent. For those thata re not aware the reason that it sounds as good as it does out there is cause the mix engineers actually go into the theatre and fine tune the EQ themselves before the opening of a major film. They try to get it as close to how it sounded in the mix down stage. Indeed this is a good tribute to how JA does his EQ'ing but he always hated them tampering with his settings for his systems....... Mark  |  IP: Logged Paul G. Thompson The Weenie Man Posts: 4718 From: Mount Vernon WA USA Registered: Nov 2000 posted 12-17-2002 08:01 PM                     Michael, I, too have nothing but great comments about the HPS-4000 system. I ran a theatre that had two of John's systems, one in the SR"D" format and the other in DTS. They were are awesome! They were smoooooooth sounding, powerful (very, I might add) with absolutely no "Booming" on the low end. I'll never forget the launch scene in the movie "Apollo 13" - It felt like shook the floors, seats, you name it! I was so proud of the beautiful tuning job John did on that system, everytime for every movie on the nights I worked, the crew of the theatre knew where I was - in the auditorium "proofing" the sound of that particular sequence. I was proud that I was the one who installed it, and John was the one who tuned it. When Kevin Bacon said in the movie "Now that was a jolt" on separation of the booster, his voice was clear and distinct, at a perfect mix. Great job by the sound track mixing engineers, the cast, and of course, John Allen! At some commercial screenings, (including Sho-West last year) the sound was good. Nice and loud, but it had an "edge" and some minor "booming" in it and was hard for me to listen to. John's system had no edge or booming on any part of the audio spectrum in the two HPS houses he tuned for me. In short, I am very impressed with the HPS-4000 system. If I owned a theatre that was capable of running the SRD, SRA, or DTS formats, I would have nothing but HPS-4000 systems. There was one more screening room I have been in that the sound was superior. It was, by far, the very best I have heard among the non-HPS-4000 houses. Although it was not a HPS 4000 system, I would rank it in the same ballpark as the HPS-4000 system. It was perfectly tuned. End of enthusiastic Rave...  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 12-17-2002 08:51 PM                     Might I ask what any of this HPS or John Allen versus whatever or whomever else has to do with Altec Lansing the 802 driver or its power handling? A new thread or a beaten to death old thread (on the very same HPS or John Allen's methods) could have been revived. Now everyone...get out of the pool! Steve  |  IP: Logged Paul G. Thompson The Weenie Man Posts: 4718 From: Mount Vernon WA USA Registered: Nov 2000 posted 12-17-2002 09:01 PM                     Good question, Steve. I was wondering that, too. But in all honesty, John showed me the RTA readout, and invited me to look at the EQ pots in the CP-55. I could not believe what I saw. When we built that theatre, John asked us for the auditorium specs, which we provided. He jammed all of this into his computer, and it spit out where to place the surround speakers and stage speakers, (at precise locations and angles down to the inch and degree, practically) and where to put BAT material in the auditoruim and where NOT to put it. Also, John indicated a few "tricks" we could use to build the speaker platforms to prevent them from becoming "resonant" to audio frequencies. We followed John's suggestions to the letter. It worked! Jeeze, those systems were nice.... I don't know, but is there a possibility that the booming Mark and others mentioned were due to fixed parameters of the auditorium that could not be changed? We did ours from new construction, and not an upgrade. I recall absolutely NO complaints from our customers whatsoever about the sound quality in those two houses unless we had an equipment failure. However, we had sound complaints from time to time in the other four houses and many of those complaints were justified according to my ears. The majority of the complaints were the levels were too high, or too low, or the mix was just "not quite right..It does not sound near as good as the bigger houses."  |  IP: Logged Michael Schaffer "Where is the Boardwalk Hotel?" Posts: 4143 From: Boston, MA Registered: Apr 2002 posted 12-17-2002 10:09 PM                        Mark, what kind of systems are these (I mean what components, which manufacturers)? Steve, sorry, it is my fault, but I had just pointed to some articles on John`s website where further reading about the actual topic can be found.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 12-17-2002 11:25 PM                     Back then they were mainly JBL. or EV components. That was back in the mid 80's at Todd-AO.I had a friend that worked at Todd-AO as a lead mixer, so I had a sort of an in there. Saul Zaentz's big mix theatre where they did Amadeus was using A-4's with the latest Altec drivers in them. Sorry Steve G. but they didn't begin to compare to the sound at Todd-AO. The Altecs had difficulty doing some of the stuff at higher levels. Dolby Labs took us to Zaentz in 84. Todd-AO used a variety of different systems but were not unlike the larger systems found in better theatres of the time. At the Lucasfilm Stag Theatre they had(may still have)JBL bass cabinets with E-V horns using JBL hf drivers. They claimed that made for the best dialog reproduction that could be had. Since I have seen/heard a couple of films there I will definately agree with them. Later on I did a number of similar systems back in the Midwest also with excellent results. In the last couple of years direct radiator systems have both gotten much better and far worse since those days. The cheapo direct radiators of both JBL, and EV are pretty bad(raw response). However the good old 2 way(4675 JBL), and the better 3 way JBL systems such as the 5672 and 5674 are amazing to say the least and I have been lucky enough to have used both of these amazing systems in new installations. Raw R-2 response readings on these systems generally only require some simple cut only eq'ing in several bands as long as room acoustics are applied properly. Similar to Johns systems. Attached is a photo of one of the three way systems....... Mark  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 12-18-2002 07:49 AM                     I have yet to hear a theatre that could not be outdone by what I have heard out of an Altec A-4...including the STAG. The STAG no longer has the JBL/EV system you spoke of Mark G (they don't have Altecs either). I'll put an Altec A-4/MR94 up against any large system or an Altec A-5/MR94 up against any smaller system any day. And as to medium horns...the MRII594 is unbeatable in my book. I do desire to hear the JBL 5000 series stuff...on the surface, it looks very well designed and has the makings of a great system based on the choice of components and construction. One curiousity is in the HF section...there appears to be a notch in the HF response (based on the specs) right above 10KHz. The JBL4675 is the best sounding JBL speaker I have personally heard I still prefer the sound of Altec and hence why I started this thread over a year ago...to show what the little drivers can and can not do in this digital age. Steve  |  IP: Logged

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