WMcD

I can appreciate the problem of geometry. My best advice is to not put speakers, particularly surrounds, close to the listener. Please do get a long length of cheap wire and experiment with placement. When faced with a constraint on room geometry and decorating, be creative. You might find that an oddball placement for a surround speaker, like under a coffee table, near the ceiling overhead, could work well enough in a compromise without being technically perfect. Gil

Aww Shucks. What can I say. It is tough to gauge when one's own input to the debate is worthwhile, or just running at the mouth. Sometimes I wonder if I write too much or too little. I do work at clarity and accuracy. So I'll take your comments as a reason to continue. Actually, you'll note that Phil H. had many of the same comments stated in a different, perhaps better, way. HornEd, you're a remarkable guy to find a creative way to keep your mom enjoining life via your hobby and enjoy it together. I'm sure it is challenging and rewarding. God bless. My motive was to give some explanation of the entire system of hardware and software which ultimately delivers sound to our ears. It came out a bit backwardly. When my boss says, "let's go back to basics", I cringe. We know this stuff. But such discussion can isolate the real basis for points of debate without getting lost in the jargon. I'm setting out things below to integrate some technical matters discussed above, and trying to put everything on one sheet of paper for the benefit of new readers. Going through the chain we have: (A) Mixing by the engineer. What the studio engineer can accomplish at the distant home end is determined by all that follows. ( How many channels are available for storage/transmission on tape, CD, DVD, radio, TV, even vinyl. © How much processing power is available in the receiver. How can it extract information given (. (D) How many speakers are available in the listening room. How do they interact with the room itself, and where the listener is sitting. The overall challenge is that (, ©, and (D) are variables in a given hardware situation at the consumer level. I think it is fair to say this an ongoing "problem" or "issue". Borrowing from the computer industry, how can all systems be made backward and forward compatible, in all platforms? What is "best" today (nothing is best for all things), and how did we get into this mess? At the beginning of the surround sound era, there were few channels ( and elementry processors ©. So wide dispersal speakers or dipoles (D) were envisioned to make up for shortcomings. Later the trend was to better processors (e.g. pro-logic and decorrelation). Then there came to be more discrete channels available in the storage media (DTS). So there was not as much reliance on electronic processing at the home end © and dispersal (D), it could be done at (A). However, as Phil H points out, not everyone has DTS or wants it. Also, we have "heritage" types of media. So, advanced home hardware HAS to simulate old types of hardware which was assumed by the engineer when the mix was put down. Better yet, let's just admit (quietly) that five or ten year old software technology IS what we listen to for the most part. - - - - - STL, correctly, points out a faux pas on my part. It is a problem of nomenclature which is vexing. Some months ago I proposed that "5.1" is, strictly, a speaker set up, (D) above. We have, counting, left surround, left main, center main, right main, right surround (that makes 5) and a subwoofer, which is the 0.1. I got some flack and dropped it. But I'll stick with it here. When we have a 6.1 system, the added integer is for the center surround speaker. This speaker nomenclature doesn't suppose to tell us about the storage/transmission channels (. That is another issue. - - - - Whoops, so what is that issue? As correctly pointed out by STL, VHS tapes have only 2 discrete channels (B above). From that, the processor (C above), creates 4 "matrix" channels. Phil H. points out that this is the majority of our listening, so let's review. The process is: and , and , . The information is further processed with a delay and other stuff, like Dolby noise reduction, frequency limiting, and then sent to both Left and Right surrounds. Therefore, the L-R signal is sent to two surrounds. This is how 4 channel matrix turns into 5 speaker outputs. We're doubling up on the rear speakers. The remaining processing is to the subwoofer. Not a matrix of adding or subtracting. It gets simply the bass from the two inputs. Again, this is the 0.1. - - - - - - Please forgive the redundancy and restatement in a different organization. Now I feel a bit more comfortable that things are set out as one grand theory in one place. Regards, Gil

I may venture a guess at the way things are going. Let's look at the "surround" situation as being just a situation on the front wall, rather than the rear. This is just for the thought experiment. Situation One: You have a mono signal. This is what early Dolby was as far as a source of the surround signal. You want to make it sound like a wall of sound from everywhere: Having two widely spaced speakers which have wide dispersion pattern fed with that mono signal would work fairly well. There would be reflections around the room. Situation One is the "old" 5.1 Dolby. It only had a single source of surround sound. It was up to the speaker wide dispersal to spread sound around the room. There is not too much to play with given a single source of program material. Situation Two: You now have three signal sources for "surround" to work with, and three speakers. Now there is a lot that the mixing engineer can do. Playing with amplitude, phase, and delay, the apparent sound source we hear can be fixed at from center, right, left, or from no localized position. We hear such effects in a "actual" three channels in front system. Situation Two is the newer surround systems with discrete multi channel surround. In Situation Two, the wide range of effects are accomplished in the mix. It would be best if the corresponding surround speakers are not wide dispersion. Rather, the same tight focus which allows best performance in the front three channels can, and perhaps should, be used. The job of creating "ambiance" or (on the other hand) discrete sources is up to the mixing engineer. The engineer can accomplish either. However, while ambiance can be accomplished with multi channel feed and narrow dispersal speakers, single apparent sources can not be as well accomplished with wide dispersal speakers, even if there are multi channels of source material. This may be why narrow dispersal speakers are better for multi channel surround. It is the same as why they they are better for the front. Now I have a question. Suppose you have a 6.1 receiver with three surround but fed by a 5.1 source, like a VHS tape. Does the receiver have a setting to compensate so that the mono surround is synthesized into ambiance across the three rear channels? Gil This message has been edited by William F. Gil McDermott on 05-29-2001 at 01:19 AM

The Speakerlab K kits used stuffing. From pictures, it seemed to be about two square feet of 3 inch thick fiberglass. Also, the plans showed that they used the top and bottom "ramps" to enlarge the back chamber. However, the instructions I've seen said to not make the cut out to communicate with the ramps. It may be that Klipsch experimented with the same and then backed away. Speakerlab rotely followed the original "improvement" and then backed away too. I'd agree. Different is sometimes only different. Gil

To my knowledge there has not been a single horn version. The design is that each horn handles about 90 degrees of arc and the two cover 180 degrees together. There was a dual woofer version. I don't think it is a question of whether they will work on a back wall, they certainly will. A better question is where any "surround" speaker set should be placed. Particularly when the size and shape of the room comes into play. Very generally, surround sound theory put the two surround speakers to the listener's left and right flank. 90 degrees from forward. They can be moved about 20 degrees forward or back from there. Not really a quad set up. Exprimentation with placement is often required for best results in a given room. This is because of acoustics or just where you might have a wall. There is a trend to 6.1 channel sound. That puts a third surround speaker someplace between the flanking surrounds to fill up the gap. So it is usually going to be on a rear wall. Would it be "better" to use the same speaker type as the front units? Conventional theory is no. Theory ONE is that the "surround" speakers should have a design so that the sound can not be localized. I.e. seem to come from a specific location. The WDST design spreads the sound around so that it seems to come from everywhere. Therefore it is "ambiance." Theory TWO is that the frequency output of the surrounds should match that of the front units. This is because a lot of sound effects is not ambiance, but a real source (car, jet) which pans from front to back or back to front. As you might imagine, this is a bit contradicatory to Theory ONE. But Klipsh uses the same or similar horns in the mains and surrounds. So things work pretty well. People have reported good results having identical speakers all around. This may be working better when you're thinking of the panning versus ambiance types of effects. From my reading, no one has ever said there is a single optimum solution. Gil

Well, you've got a 4.1 system (5 speakers), so that is a start on your knowledge. Excuse me if the following is obvious, or too general. It seems you're looking for the very basics. The standard HT system has 6 speakers. This makes it a 5.1 system. (The subwoofer is the .1, there are 5 others) The first speakers to consider are left and right main. These are basically equivalent to a 'stereo' set up. Just like the fronts of your 4.1. I'll point out that if you are going to get a subwoofer, these don't have be the top of the line. The sub is going to be doing most of the work. Then you add a center channel speaker. It is smaller than the mains. It sits in the center on top or below your TV. This is good for localizing sound in a wide stage. Often speech in a movie which is centered. There is no analogy in your 4.1 system. Then there are the surround speakers which are placed to the side and back. These are just like your rear speakers on the 4.1 system. The elementry system uses two. These again are small in size but different in construction from the center. In Klipsch HT speakers they each have two horns set 90 degrees from each other to send treble over a wide lateral direction. There is a small bass driver between them in the cabinet. Then you need a subwoofer which will be similar to the one in your 4.1 system, but bigger. It sits on the floor someplace near a corner, usually. You can play with placement, but it is not critical at first. You might play with it. You should be able to go to your Klipsch dealer. He'll recommend the full set of speakers from the same family. This is important. The 5 speakers should come from the same family which are thus designed to work together. Choice of the sub depends on your ambition. Obviously, it makes sense to get a Klipsch. Typically there will be a small, medium, and large, in graduated price too. Then you need an HT receiver and video source (VHS, DVD). You see the favorite brands of the many folks on the bbs here. I'll go out on a limb and say that you can't go far wrong with the major manufacturers from Japan: Sony, Denon, Yamaha, Mitsubishi. Again, the midpriced stuff is probably a good choice. The HT receiver will have the connections to drive the 6 speakers. I don't know if you're set with a VCR or DVD player. To my way of thinking, it makes sense to get the same brand as the HT receiver. At least the remote controls are likely to function better, together. Everyone has thoughts on the wire you'll need to connect all this. I think zip cord is good enough for speaker connections. At least it is a cheap start and you can upgrade later. You'll need something to connect the DVD or VHS. Cheap is good enough for now. That is the basics. Like buying anything, you might be worried about making a bad choice. Am I being sold an overpriced econobox, a Corvette, a old Cadillac, a Pentium 2 when the Pentium 7 is coming out soon, or what? Normal fear. Essentially, you will probabably always be well served with the midrange price and size in a current model. A good dealer can be a big help. All this equipment is a big investment; you deserve serious treatment. Make it clear that you want something close to a turn key system (if that is true) which is similar to a mid range car. Not a luxury model, and not an economy model. Of course, the above depends a bit on your personal situation. I think the mid-priced stuff is darn good and gives best bang for the buck. Others on the forum might come forward with specific choices. Regards, Gil

Ya know, this whole phase shift thing is poorly explained in the technical area. It is really that in a capacitor, the current is the slope of the voltage, hence current is a cosine as compaired to a sinusoidal voltage. Whoops, I wandered into the wrong chat room. Sorry. You're talking economics and politics. =8^o Gil

James, I really don't have any easy solutions to suggest. But a few more observations. Does anyone mind a long post? Everyone has a theory. Real scientific evidence is hard to come by. Talk is cheap. Take it all with a grain of salt. I certainly don't want to lead you astray. I doubt the probem is a simple reflection off the wall behind the Belle. The distance of 18 inches, or 36 inches in path length is just not long enough to create a bass problem. When there is a problem with the bounce off the wall just behind, it is called an Allison (sp?, the guy who described it) dip. It is usually in the midrange or upper bass. Not 50 Hz. People solve it by moving the speaker a bit away from the wall. I suppose there is some chance you've formed a cavity resonator in the space behind the Belle. Pulling the Belle out a bit might be an experiment. The room dimensions sound dangerous. They are close to 1:2:2. That is very suspect. Not as bad as a cube with 1:1:1, but almost as bad. You've got half a cube. I'll send you, and anyone else, a copy of the Dope from Hope on room dimensions if you e-mail me your postal address. Some folks seem to think you should have 1: 1.6 : (1.6 x 1.6) ratio. Golden mean, progression. I've read of some software which will predict problems with room modes. Perhaps someone on the forum can suggest a source. The present problem seems to be that you're not going to be able to move the speaker location, you can't move the walls, equalization doesn't work. What is left to do? Maybe absorptive material as suggested, but one must be realistic. I've read that even anechoic test chambers used by the manufacturers don't absorb perfectly well below 200 Hz. Of course what is perfectly without echos is not what is necessary to solve a given problem. The issue with absorbing bass is that the absorber has be almost as big as the wavelength of the sound in free space. Therefore, even a 4' x 8' panel might not be enough. Measured results of sound absorbing material show that they work well in the treble, and not very much at all in the bass. I think the problem is that even if they are relatively wide and tall, they are not deep. So they don't absorb bass frequencies. One technique which I've read of, and not experimented with, are "tube traps" placed in corners. These are essentially columns of fiberglass roughtly 1 or 1.5 foot diameter. Usually hollow. The fiberglass batting can be trapped between coaxial cylinders of wire mesh. So you have a maybe a 1.5 foot diameter outside cylinder and a 1 foot inside cylinder, with fiberglass in between. Then these are placed in the corner. How tall? Maybe 4 feet. Floor to ceiling would be better. This is almost silly because it is like building the Great Wall of China with no guarantee of success. But interesting to talk about. There is some good reasons to think these would work even in view of the wave mechanics. They are sort of like absorbing K-Horns in the corner (for you the back corners). Just as corner placement of the K-Horn magnifies it's apparent size by 8 (in theory), here the absorbers are 8 times bigger when placed in a corner. If they are up to the ceiling, you're putting in two at either corner of the room. Clearly only a fanatic would do something like this. Would a couple of over stuffed Lazy Boy recliners in the corners absorb as well? I dunno. Hard data is difficult to come by. I've had my own interesting failures. I had a three channel set up in a garage. I made sweeps with the mike at four positions using an LMS system, and averaged them. Then I opened the garage door to remove the sixth wall. Ran the sweeps again. This was going to be real dramatic. The change was almost nothing. Cue the Therimin music and Outer Limits theme. Either my set up was all wrong, my understanding was all wrong, or the garage door had never been substantial enough to serve as a wall for the bass in the first place. Probably a lot of all three. Amateur acoustics is a bear. Gil This message has been edited by William F. Gil McDermott on 05-15-2001 at 09:12 PM

If I may comment on James' issue. Mostly theory here. (Am I being a prig?) Suppose you have a reference level of 90 dB. If a relection is equal and out of phase by 180 degrees, then you can have a null down to nothing at that location. (Call it 0 dB.) Obviously a perfect reflection is impossible except in a tube. However, roughly speaking, it could cause a null (cancellation) down to absolute silence. Certainly a 20 dB "loss" at a node in a room is more than possible. On the other hand, a perfect reflection could lead to a +3 dB or so peak at a location where it in phase. About double power. But that is all. You can't get a 20 dB peak from an in phase reflection. The conclusion is that the peaks are limited to about +3 dB. But nulls really are deep holes. It's not too far off to say that you wind up with 93 dB at a peak and 70 dB at a null). I used a tone generator putting out about 50 Hz and walked around as an experiment. At one spot, you'd think the speaker wasn't working at all. At other spots a few steps away, the sound is more than healthy. The problem with equalization is that you can crank up the source, but the out of phase reflection goes up by the same relative amount and cancels by the same strength! So the hole is still there. In short, James' observations are certainly well based in physics. The math works out that the mountains are not so high, but the valley are really low, and there is little you can do about them with equalization. Of course the real "problem" is that if you shift the frequency up or down by a few notes, the peaks and nulls move to other locations in the room. Gil

Like Bose, they too deliver plain vanilla ice cream by the bucket for the price of premium Haagen-Dazs. Wow, such a turn of phrase. Nicely done. TM mark too. How do you do that? With the Alt Key ? No, I'm not being sarcastic. It is interesting to read a passionate statement well crafted. I'm in agreement with some of the above, but coming from a different angle. It seems to me that Bach and Beethoven were as much bass fanatics are we are. JSB's organ pieces and LvB's symphonies certainly show it. Unfortunately, most consumers have not hear such works "live". It is understandable that consumers will accept a stylish small system to listen to music just like they've always heard it. And think this is good. About once a year I visit the CSO to hear a big work at Orchestra Hall. Like PWK says, calibrate your ears. Never does the experience bring to mind small speakers, like a Bose cube. Even with a sub. Always a K-Horn. Styling aside. If someone wants ALL of JSB or LvB in their living room, the reproducer is going to have to be of a large size. The average consumer might not like that, but tough. Some blue nose might have said to JSB that they like the music, but couldn't you make the organ smaller. Nope, can't be done. Regards, Gil This message has been edited by William F. Gil McDermott on 05-13-2001 at 10:10 AM

Regarding the book. Check audioxpress.com It is listed there as being on sale. Your local library can probably get it on interlibrary loan for your, if they can find a copy. It was supposed to be at DePaul University Chicago but was missing from the shelf, and evidently has been for some time. I finally found a copy at Illinois Institute of Technology Galvin Library, Chicago. Wonder of wonders, it had markings of DePaul Library. Guess it got sold somehow. Gil

Yeah, it certainly should. I must admit I've never seen the specifics of back loading versus front loading discussed. I'll talk about technical stuff and math. Some people like it. My own form of rant. - - - The closest I've seen about the strucure is in some old midrange drivers. They are front loaded with the horn on the opposite side of the diphragm from the the magnet structure. However, there is a vent at the rear which seems to be open to the air except for some wool. The latter probably acts like an accousic resistence. Even with this, no one is questioning that the basic engineering applies. - - - - There are several electrical analogies to the combination of the rear box, the driver components, the chamber in front of the driver, and the connected to the horn. As you can imagine, the back loaded horn is very similar to the front loaded horn (the horn is at the back side rather than the front). The difference is that there is no back box, in front. Rather the diaphragm radiates. This way there is mid range frequency sound radiated directly. The Klipsch Rebel (original ones) and Short Horn, were back loaded, but had a box between the driver and the horn. Otherwise similar to the Imperial in concept. There was radiation off the front of the driver. - - - - This is the math and electrical engineering stuff. It took me quite a while to realize how an increase in overall resistance could lead to a system which is more efficient. I pass it along. The following is more complicated than some readers need, and more simplified than others need. There is a simplified electrical analogy to the direct radiating diaphragm and the horn loaded diaphragm. Both are same in structure of the analogy. Only the numbers change. The implications are grand. It is important to realize that in a speaker, some of the electrical energy is used to just heat up the voice coil of the motor (VC), some of it makes sound because it is being delivered into an abstraction called, by me, radiation resistance (RR). I'll plug in some values which are just for example. The RR value is something I pick out of the air to make math easy. For the direct radiating diaphragm: (+)----------(-) I'm showing the plus (+) and minus (-) electrical input to the speaker as a whole. That is what the amplifier is driving or "sees". The "VC" is the voice coil resistance which I'm assuming is 8 ohms. The "RR" is the radiation resistance of the diaphragm. The air load is not resisting movement of the diaphragm. So it is given a low resistance. Essentially, the power into the voice coil resistance results just in heat. The power into the radiation resisance results in sound. In the above circuit, the total resistance is 8.8 ohms. There is not much power absorbed by the RR because it is only 0.8 ohms. The voice coil resistace is absorbing most of the power. Let me be honest and do the math. If there are 1.1 volts applied, the voltage across the VC is 1.0 volt. The voltage across the RR is 0.1 volts. (Classic voltage divider.) We know that Power (watts) = V x V / R. So for the power to the Radiation Resistance we calculate 0.1 x 0.1 / 0.8 = 0.00125 watts. That is the analogy to the acoustic sound output from the direct radiator. Putting the diaphragm of the the same driver up against a horn alters things. Now the diaphragm has to pump air into the throat of the horn. It resists mechanical movement more. The circuit values for an optimized horn looks like this: (+)----------(-) Please note that the RR value is now equal to the VC value. Otherwise, the circuit is the same. The total resistance is now 16 ohms. And you might wonder . . . . The overall resistance load has gone up! In comparison to the first example, we're drawing about half the current with the same voltage. (P = volts x current.) So the electrical power delivered overall must be about half. That is absolutely correct. However, lets look at the power being delivered into the altered radiation resistance. Again we apply the same 1.1 volt at the the (+) and (-). Now there is an equal voltage drop across each resister of the analogy. Therefore we have a voltage across RR of 0.55 volts, and its resistance is 8.0 ohms. Let's do the power calculation for RR. We know that Power = V x V / R. Plugging in the numbers: 0.55 x 0.55 / 8.0 = 0.037 watts into RR. Wow! Even though the overall resistance seen by the amplifier has doubled, the power into the radiation resistance has increased. The ratio of the increase of power to the RR (horn loading versus direct radiation) is: 0.037 watts / 0.00125 watts = 29.6 We can calcuate that in dB. 10 x Log(10) of 29.6 = +14.7 dB. Also, the overall power drawn from the amp is about half. Call that another 3 dB of power gain. - - - - I can't crawl into PWK's head, but you can imagine the implications of horn loading to any engineer. There is a grand increase of power transfer, even though the amplifier is being asked to deliver less power! Regards, Gil

Edit problem. Gil

I'm in the situation of having deferred all purchases for Audio and Visual while prices come down and standards get consolidated, while my personal funds go up. Eventually there will be a big purchase. I'd never buy any other speaker brand than K. I'd probably buy the same brand audio electronics and video monitor unless something changes. However, maybe Klipsch will come out with an electronics line, and I'd go for that. Recent acquisitions by Klipsch are headed that way. This is somewhat a tip off to the Klipsch corporate marketing people. In years past I'd consider an oriental source for everything except speakers, with speakers being Klipsch. However, maybe Klipsch will start eating their way up the stream of components. The first stop is clearly electronics. Would they ever be able to get into video including display and DVD? I can't caluculate. Maybe they'd go into parnership with someone. There have been some unkind remarks about non-Heritage speakers and what is obviously a matter of reaching lower price points and a rare QC problem. These I can understand, and tolerate. I'd dislike a situation where the Klipsch name becomes just a marketing tool for the mass market without superior technology. E.g. I see "RCA" high definition speaker wire at Home Depot. Gil

It is unlikely that a driver with other parameters is going to yield improved results. In an automobile, you can install a more powerful engine, and get more acceleration. However, it doesn't work like that with speakers. There are interactions between the speaker T-S parameters (Qts, Vas, Fs) and the box volume and port. The trick is to get them all working together correctly. It ain't simple. Putting in a different speaker is very likely to make things overall different. But "different" is unlikely to be "better" without a lot of calculations. This is pretty much engineering fact. - - - A lot of people endorse cross bracing. The theory is that the box is flexing, and should not. Whether the Cornwall has such a problem to any significant extent is a matter of conjecture. "Tighter" bass is often reported by tweekers applying bracing to any project. In this matter, engineering theory favors bracing and I'm not telling you theory is not in your favor. On the other hand, the magnitude of the problem, and solution, may be more imagined than real. Regards, Gil

My brother in law has a Yamaha "Natural Sound" amp. It has Dolby Surround. Is that your situation? You're writing about surround speakers, so it raises the question. - - - - - Returning to the "ohms" stuff. A lot of receivers have A and B switches for speakers. Sometimes called main and remote. However, it is not a matter that the amp is intelligent and sends half its power to each and will throttle back to make itself happy. This is because the switches just hook up the speakers, in parallel, to the same amplifier output. It can run it self into distruction. This is like hooking up two appliances to the same outlet through an extension cord. Or even connecting the two appliances into the same wall box. If you turn on both appliances at the same time, they get the same voltage, and draw current according to their resistance in "ohms". If you connect too many appliances they draw too much current and the fuse blows. In the case of the amp, the output circuit will either, (1) start distorting, (2) trip out a current limiting circuit, or (3) burn itself out. Some amps can take two speaker in parallel. But three is pushing it. Resistance is really describing the relation between the voltage delivered to the speaker (V) and the current (I) it will draw. Resistance (Ohms) = V / I So if you apply 8 volts to an 8 ohm speaker, the speaker draws 1 ampere of current. 8 = 8/1 Lets take a look at two 8 ohm speakers attached in parallel to the same amplifier (like the two appliances). Again we assume that 8 volts is applied. Each speaker draws 1 ampere, for a total of 2 amperes being demanded from the amp. What is the effective resistance? We use the same equation, kinda backards. 8 volts/2 amperes = 4 ohms. You can use the same principle assuming three speakers in parallel. Now there are 3 amperes drawn, total. 8 volts / 3 amperes = 2.66 ohms. Now you can see how parallel circuits reduce the effective resistance. In fact, 8 volts is pretty high to deliver to home speakers. You often see speaker sensitivity tested at 2.83 volts into a presumed 8 ohm speaker. That is pretty realistic and equates to 1 watt. Lets use the same form of the equation. 8 (ohms) = 2.83 (volts) / I Doing some algebra 2.83/8.0 = 0.35 = I or current. We also read that voltage time current equals power in watts. V x I = power. Lets plug in the numbers. 2.83 x 0.35 = 1 watt. That is why the number of 2.83 volts is used. The above is just to show you a simple way of calculating how parallel resitances can be calculated. The real equation is that 1/Rt = 1/R(a) + 1/R( + 1/R© But what I've shown above is the same and makes more sense. - - - - So, is this a surround system? The surround channels use an additional amplifier. Regards, Gil

Forgive me if I asked too many dumb questions. I was also thinking that B&O headquarters is a lot closer to the Benelux countries than Nebraska. I would enjoy hearing about the solution. BTW there is a B&O showroom on LaSalle Street, just about three blocks from where I work. Someday I'll not be able to resist the call. Regards, Gil

John, You should be ashamed of yourself! Give them a chance. Gil

I'd certainly suggest you read all the books and consult with experts. However, a few observations. The main theory is that they problably will write about wall to wall transmission, rather than ceiling to floor transmission. So be wary of how the principles are applied in your circumstances. One main means of isolation between rooms involves having massive walls -- actually so the walls don't act like light weight speaker diaphragms and re-transmit the sound. It may be that the floor of the room above is massive enough simply because it has to support structural weight. It'll be more massive than most thicknesses of sheetrock. Therefore you already have a massive wall in the form of a floor. Another means to isolate rooms is to have the walls on different studs. That way the studs don't transmit the sound from one piece of sheetrock to the the next. Making a basement ceiling of any significant mass which is not supported by the floor above seems complicated. Perhaps un-necessary. You will probably also read that the transmission of sound is often through holes which communicate between the two room. Therefore people suggest that gaps in electrical outlets, HVAC ducts, and doors, be sealed. This might be a major problem because the basement is often used as the space where such utilities are routed to the rooms above. You might take a survey right now in the reverse direction. Is sound from the ground floor being transmitted into the basement? If you can figure out what is allowing that, you might have a better idea of what needs to be cured. Yeah, really, if you play Pink Floyd on a boom box in the kitchen (while mom and the kid are shopping) perhaps you can identify the problem areas. There is a Dope From Hope on isolation which I don't have here. (I can send you a copy if you give me your postal address.) Essentially, PWK was trying to isolate a band room at U of Ak. He used maliable sheet lead to seal off chinks in the HVAC system. Some less toxic material could be used these days. Weather stipping on the door down to the basement could be a big factor! It is probable that you have tons of concrete in the basement walls, and lots of wood or concrete in the ceiling / floor. Yet the door to the basement is made of very light weight material and is not sealing against the doorframe. My impression is that it is possible to build a Mageaneu Line (sp??? very) and the sound makes an end run. Regards, Gil

This is a shot in the dark. I don't have a clue about the actual design of the mechanism. It seems that something was altered when you installed the new electronic equipment. So, threes suggestions of where to look. It is tough to do without picures. 1) Can you put things back the way they were before, electronically. I doubt it is an electronic problem but . . . Maybe a grounding situation, noise getting into the electronic? 2) Regarding the platter. The fact that the belt is at a different position sets off alarms in my head. Is this something that has an outside ring which you lift off, and then you see an inside ring which is driven by the belt? The old AR's were like this. Also, does the inside ring "float" on springs? There might be some procedure where you have to hold down the inner ring while it is running to get the belt to ride up to the old position. Then stop the motor and put the heavy outside ring into position. The other way the design might work is with the belt driving the outer rim of a one piece platter. If you can see where the belt comes off the driven platter, you might coax it up to the old position so that it feeds on the drive pulley at the correct position. Sort of like a bicycle derailer. This might also apply to a situation of an inner and outer ring. 3) It might be that the mechanical mechanism is okay and the motor speed controls everything. There must be a switch to switch between 45 and 33. Does that seem to mechanically actuate properly? Silly last question. You're in "ne". Neitherlands or Nebraska, or someplace else? Sorry I can't tell you more. Gil

Can you help us a bit here? Looking at it, can you tell us whether the change in speed is normally accomplished electrically, or on the other hand, mechanically. I mean in normal operation. If it is a mechanical system, there is some mechanism which shifts the belt to a smaller diameter drum on the drive motor for 33 rpm. Maybe that is the problem. It might make some sense if you're seeing the belt running at a lower line on the "drum". This is to say, some mechanical mis alignment. But, Mr. R., which drum? The one on the turntable? Even if you have a system where the speed of the drive motor is the control, if the belt shifts, it could be the cause. If everything is normal, a loose belt would normally cause slippage, and therefore a slower speed, not higher. So, that is probably not the simple answer. Gil

I'm very intersested in how the new video systems work. Some discussion of the "old system" is warranted. The "pull down" is interesting. I recall it is to allow a 24 frame per second film be shown on a 30 frame per second video system. Neat trick. (Bear with me, the video is actually 60 field per second.) I set out the following of what I understand. It might be a little off. I tend to recall what I inferred, rather than the raw data. Okay, we know that motion pictures are made up of a sucession of still pictures (frames) and they change every 1/24th of a second. We see 24 every second in the movie theater. Video is said to be 30 still pictures every second. But we know they are painted line by line. The video frame is interlaced, which is to say it is repeated in the video signal as two "fields." In a way, the transmission is 60 "fields" (which are sort of half video frames) every second. Odd numbered lines are traced in the first 1/60 of second then even lines, in the second 1/60th of a second. (Or maybe even then odd.) This is the "interlacing." Line 1 (painted first sweep) Line 2 (we'll come back after we're through with all the odd lines, in 1/60th of second) Line 3 (painted in the second sweep) Line 4 (painted after line 2, when we get to it, after 1/60 second) Line 5 (painted in the third sweep). It is a bit confusing without diagrams . . . however an appreciation of the tele-cine system is something else. In real time, the video signal is really a 60 fields per second system. Yup there is the potential of painting 60 different pictures every second under the NTSC video system. They are "interlaced" together (per the above). None the less, how to make the rates work together? This is the tele-cine system used to convert film (24 still pictures per second) to video (60 still pictures per second). Smart cookies came up with this half a century ago. The conversion into video is" Video Frame 1, Field 1 = Show Film Frame 1 (1/60th of a second, cumulative time.) Video Frame 1, Field 2 = Show Film Frame 1 (2/60th of a second, cumulative time.) Video Frame 2, Field 1 = Show Film Frame 1 (3/60th of a second, cumulative time.) Video Frame 2, Field 2 = Show Film Frame 2 4/60th of a second, cumulative time.) Video Frame 3, Field 1 = Show Film Frame 2 5/60th of a second, cumulative time.) Wow. Look at the 5/60th second cumulative time figure. That is 1/12th of a second. We've displayed 2 of the 24 frames per second film frames which each last 1/24th of a second. (1/12th second). We've done that in 5 fields of video, or 2.5 frames of video. 2.5 x 1/30 = 1/12th second. (Same for 5 x 1/60 seconds.) The next transmission is Video Frame 3, Field 2 = Show Film Frame 3 6/60th of a second, cumulative time.) Video Frame 4, Field 1 = Show Film Frame 3 7/60th of a second, cumulative time.) Video Frame 4, Field 2 = Show Film Frame 3 8/60th of a second, cumulative time.) Video Frame 5, Field 1 = Show Film Frame 4 (9/60th of a second, cumulative time.) Video Frame 5, Field 2 = Show Film Frame 4 (10/60th of a second, cumulative time.) Okay let's check timing again. 10/60ths of a second is 1/6 second cumulative time. We've sampled 4 frames of film each lasting 1/24th of a second. (4 x 1/24 = 1/6) The samples have been put into 10 video fields or 5 video frames. 5 x 1/30 = 1/6 second. Confused by these fractions? Me too, and I wrote them. Let's look at the conversion in terms of film frames 1/24th second and video fields (half frames) 1/60th second. I'm going to sequentially number the film frames and video fields (half frames). This is the same information expressed above. Video (half frame) <=Input from Film 1 < = 1 2 < = 1 3 < = 1 4 < = 2 5 < = 2 This is where we made our first break to look at the numbers. (Hey, look at the 3:2 ratio of film frames used as input!) We continued: 6 < = 3 7 < = 3 8 < = 3 9 < = 4 10 < = 4 Hmm, we can conclude that the film frames are being sampled, but even numbered film frames are not being represented as much as odd ones. (Note, this is not interlacing.) It seems to me that the video card is undoing the "pull down" system. Am I correct that the monitor is then running at 24 frames per second, or maybe 48 frames? I'd be happy to have some input. Why is it called pull down? It may come from the mechanical mechanism in the film projector which pulls down the length of film to put a new little picture into position. As we can see, the new film frames are pulled down at at 3:2 ratio. All comments, discussion, corrections, are more than welcome. Regards, Gil

Well, I say the hobby can be defended as being less expensive and time consuming than duck hunting. And it keeps the man home. Assuming that is a plus for the woman. On the other hand, living rooms are sometimes the jurisdiction of the female. Yeah, your right. We can't win. Bachelor Gil

Yeah. Good work John. That was a picture of the one in the Klipsch museum. I thought the styling was a nice variation on the standard types. Gil

This does sound like a connection problem. At high volume levels, the signal breaks through the insulation or bad connection. I'd cycle all switches and volume controls and plug and unplug all connecting wires. You seem to have eliminated the speaker wires by monitoring with headphones. Excuse me if this is intuitively obvious. Gil