The HPS-4000® systems do basically sound the same (they have similar tone) and they sound as natural as I can make them. Since I have done each and every one, there is an advantage of consistency if nothing else. I believe that the article you refer to said that all screen channels should have the same equalization settings, provided they are the same speakers. This is the only way that the three channels will sound the same. It is also the best way to ensure the widest and deepest stereo image. I don't recall ever saying anything about swapping cards.

The far field measurements have little relevance to anything. Blauert refers to the reverberation repression done by our brains in filtering out later arrivals of a sound for a period of time after we hear the direct sound. I like to use the speaker phone analogy. We hear an echo of the room when someone speaks to us on a speakerphone, but we cannot hear that reverberation when we are standing next to the person speaking. Our brains won't permit it. Since microphones don't have brains, we need to try to trick our measurements to behave more like our hearing system and focus on what our hearing focuses on. The far field measurement doesn't work and should be abandoned.

Equalization of movie theatre sound systems is a double edged sword. Properly applied, it can solve problems. But since it is almost never properly applied, I fear that, in most instances, it introduces more problems that it solves.

I have not claimed that only HPS-4000® sound systems have the output required to do their job. I have said that all of them do.

Rooms the size of most movie theatre are not large enough to have reverberation time problems with good loudspeakers. If you can understand a person talking from the front of the theatre, but not the sound system, it's not the acoustics that are to blame. What I do pay attention to are the surface treatments, where they are applied and not applied. The noise spec has always been NC-25.

Good to hear from you!

 |  IP: Logged

May I suggest that you and Brad visit the Preferred Theatres section of the HPS-4000® web site: http://www.hps4000.com

I did this page as a list of theatres where I am reasonably comfortable, if not absolutely certain, that they are properly maintained.

Should you wish to visit the Boston area, the General Cinema Framingham complex has 13 systems installed. Theatre #6 is my reference theatre. It is outfitted with our four-way screen speakers, eight channels and has superior amplifiers. The new theatre #1 also has superior amplifiers as well as our four-way screen speakers.

Regarding Brad's comment about different theatres sounding different: Of course they will. However, our systems do have far more consistent tone from one theatre to another than any other sound system I have ever heard.

I notice that all speakers must be Klipsch. Why is that? Is it a personal preference? Also, why do the speakers have to be so close to the screen? Ever thought of using baffle walls or bafflettes? (I'm sorry, I don't get BoxOffice magazine at my current theatre, and these topics may have been covered by you in there since I stopped getting it).

For professional purposes, the definition I have used to describe good sound is that which sounds like the original. While we must be honest and admit that it is not possible to reproduce what went into the microphone(s), we can do a satisfactory job at creating the illusion of auditory perspective and tone. Judging how well this is accomplished is a matter of training and years of experience, as much as personal taste. The experience and training is necessary to be able to listen beyond what we like and may not like. Some people listen primarily to the strings of an orchestra, for instance, when there is a great deal more going on.

So, indeed, we all have the right to our tastes, prejudices and levels of experience. I would caution anyone, however, not to expect to gain much proficiency by listing to loudspeakers, any loudspeakers -- even ours.

As to your question about the speakers: Klipsch made all my speakers until 1986. At that time the SR-70 surround speaker became available and our customers started to use it as well. By 1995, the Klipsch professional division had been sold twice. The company I was left with (which was not Klipsch) was not satisfactory. Since then I have had all my speakers built by the original inventor of our large 545 system and the SR-70. The other firm that had been unsatisfactory in 1995, ultimately went out of business. Today, I would have no objection to having speakers built by Klipsch again. In fact, I fully expect that to occur. The reason for using them initially in 1979, was that they were they best source for fully horn loaded loudspeakers.

The speakers must be close to the screen to eliminate behind-the-screen reflections. Our speakers have been designed for this. This has the advantage of eliminating any need for sound absorptive materials to be installed behind the screen. I do use baffle walls in certain cases where there is an exit corridor under the screen, forcing me to place the woofers above the HF sections, which I want to remain at their optimum height.

 |  IP: Logged

Does the sound retain it's characteristics as it travels around the room? The only place where I have heard the sound do this accurately was at a theatre which used the exact same speaker for surround purposes as the stage speakers. There really isn't any way that a tiny surround speaker (even in multiple numbers) can match the tonal balance of a giant horn loaded quadruple bass bin speaker. If it can, why not just use the tiny surrounds behind the screen as well and save tons of money?

Ten of our surrounds equal the output and radiating area of one of our large screen speakers. That's one of the reasons that our surrounds match the output of one of our screen channels. The matching of tone is accomplished by using horn loaded midrange and tweeter sections in the surround speakers, driven with the same drivers that are used in the screen speakers. My Allen Surround Array™ speaker placement formulas provide the surround locations required to achieve extremely uniform coverage, typically ±1/2 dB throughout the surrounded area.

Deep bass is non directional when it is playing continuously. For instance, if you walked into a hall when a 32 foot organ pipe was playing, you will probably not be able to discern its direction. However, when a low frequency sound begins, you can almost always tell where its coming from. Also, a loud bass transient will produce a wave front. You can always tell the direction of the wind in that situation.

My surround arrays are not equalized at all. They produce a uniform field with a very smooth and flat frequency response on their own. Because the speakers have a relatively high directional characteristic, we are never in what I call the far field. We are always effectively in the near field of the speakers. They aren't that far away after all.

The comb filtering effect is taken care of by the multitude of speakers and their distance from each other, not to mention the advantages of stereo surrounds. Even if there was a comb filtering problem, one would only detect it by walking around and no one is walking around when they are watching a film unless they get up to go somewhere. When I do walk around a theatre while the surrounds are playing, as I did today, I hear no comb filtering effects at all.

The surround speakers have 12 inch woofers in a well tuned sealed box. There are usually 10 or 12 of them. They can produce a fair amount of bass. (You should have heard TWISTER.) One of them is always placed in each of the rear corners. (There is a special formula for the rear corner units.) The corner placement provides many benefits. One of them is better bass.

It's interesting: Showscan used to use two identical speakers for the left and right rear speakers rather than a full set of surrounds. I told them that with my system, they would hear both directional and non-directional effects beautifully as well as full dynamics. When they heard their films on the HPS-4000® system installed at their headquarters on a 45 day trial, they believed me. The "trial" was over in 45 minutes and the system is still there.

Yes, the theatres around the Chicago are owned by Mr. Johnson. You should pay him a visit sometime.

Second, how do you handle the pulling of certification to theatres who do not keep it maintained properly? Many THX theatres will be left to turn to shit and yet they continue to have certification so long as the checks keep going to Lucasfilm. Then again, many THX theatres are maintained extraordinarily well and provide an amazing sound experience. How strict are you on your certification and how do you keep track since you are the only tech? Also, what do you allow techs to do to your systems in your absense without getting their certification pulled.

You said you have different levels of the system. Can you give a brief rundown on them? Please include facts such as speaker sensitivity and amplifier power.

I've read your articles in Box Office magazine on how to get a better eq and such. You have very non-standardized methods as opposed to the rest of the industry. I'm not saying that they aren't superior, just very different. How does this affect the playback of a film in an HPS-4000 auditorium that was mixed in an auditorium that was equalized using the standard methods the rest of the industry has adopted?

You like Klipsch speakers obviously. Do you allow any other brands for use in HPS-4000 installations, or is it a monopoly situation where all HPS-4000 theatres absolutely must purchase the Klipsch system? And do you own stock in Klipsch?

Since you insist on Klipsch, do you insist on a certain digital format for playback? Do you have a preference? Also, what is your analog processor of choice? I've never heard a mention of this. Does it matter?

How about home HPS-4000 systems? Is this strictly a cinema system? I think the home THX systems are a complete joke and have never been impressed with one to date. Have you tapped into that market yet? If so, do you personally go into every person's home and perform the equalization?

To answer your last question first, the "®" is required to be used by trademark owners should they ever find themselves having to defend their registration against someone who might want to say that the owner didn't maintain it and no longer should be entitled to it. In short, my lawyers recommend it and if you must know, I think it's kind of a pain. The keystroke is "option-r", at least on my machine, if you wish to try one for yourself.

I believe that I explained that not all my systems have been done with Klipsch-built speakers. I do not own stock in Klipsch or any speaker company except my own, and of that I own 100 percent.

The HPS-4000® system is priced very competitively. When pricing is compared with other systems designed to have an equal acoustic output, our system is about 30 to 50 percent less expensive. This is due to the efficiency of the speakers. The speakers cost more, but that allows everything else to cost so much less that the entire package becomes very economical.

I personally train the technicians that service HPS-4000® systems. Most of them have the same equipment I have. I calibrate their equipment or provide them with a B&K 4231 microphone calibrator referenced to my own. The equalization is never changed, so all one needs to do is maintain the "A" chain and correct for level drifting once or twice a year. That's not a lot to do. I have a fairly close relationship with my clients, so I can be pretty certain as to whether I can list a theatre on the preferred list.

The four systems all have the same surround speakers and subwoofer cabinets. Only the screen speakers are different. They are matched to theatres by the size of the room. While the largest speakers can be used in any theatre, I make sure that our smaller screen speakers do not get placed in theatres that are too large for them.

Presently, I am using Dolby processors for analog.

The speaker sensitivity of our large 545 three-way and four-way systems as well as our 545-W subwoofer is 109 dB per watt per meter. This is the wide-band sensitivity, not just the middle frequencies. The two smaller systems are 106 dB per watt per meter. The SR-70 surround speakers are 98 dB. The amplifier power is specified to ensure that when the first arrival of the loudest sound a film can produce is delivered to the center of the theatre, the amplifier will be at no more than 25 percent of its output. This is true for all channels including the subwoofer.

I have done two home HPS® (another trademark, sorry) systems. (I actually did my first home-theatre installation in 1974. It was not HPS® at the time.) The HPS-4000® system will only be sold to theatres. This allows the exhibitors to have something you can't get at home. The home HPS® systems have used similar approaches but were only done because I knew the people involved and wanted to help them. Beyond that, I do not have time to do retail.

One last point: Producers have always told me that their movies sound better in my theatres than they do at the studios. Sir David Lean personally told me (while literally shaking me in excitement) that the Dolby "A" optical soundtrack print of A PASSAGE TO INDIA sounded better at the Century Plaza Theatre than the masters did on the rerecording stage. Producers are amazed at the sounds they can hear that do not get delivered anywhere else they have heard their film.