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Q&A # 197 - September 16, 2000

Staff

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Q Do anamorphic camera lenses put more picture on the film than regular lenses?

A Anamorphic lenses have two parts, one being the prime lens, and the other being the anamorphic lens (at least that is the way they started out). A 100mm anamorphic lens has a 100mm prime lens and a 50mm anamorphic lens, but that is simply the label it is given. It has a focal length of 100mm vertically and 50mm horizontally. You could just as easily call it a 50mm lens because it has a focal length of 50mm side to side. The two focal lengths make the lens very astigmatic, and as a result, focus is critical. The anamorphic properties fill the frame on the movie film, which produces more light on the screen than if the image were simply cropped to give the long horizontal rectangle in widescreen movies. So, if you leave the 100mm anamorphic lens label as is, it produces twice as much field of view, onto the film, as a regular 100mm lens. If you call it a 50mm lens, it produces half as much field of view, onto the film, as a regular 50mm lens. For a conventional lens, a circle is produced when light from a scene goes through it. For the most field of view, the complete circle would have to go onto the film. That is not very aesthetic, though, so the image is framed by rectangles. The original one had an aspect ratio of 4:3. As the image is framed by higher and higher aspect ratios, such as 16:9 and 2.35:1, more and more of the image coming through the lens is tossed out. Even a 100mm anamorphic lens, with its 50mm anamorphic lens portion, is recording onto the film only half of what it would have if it were a regular 50mm lens, due to the prime lens being 100mm.

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Q I saw a device that lets you spin a CD on it, and this is supposed to improve the sound. Do you know what it is, and does it work?

A You are thinking of the Bedini Clarifier. It is supposed to do something to the molecules in the plastic substrate of the CD through a demagnetizing process. However, here is how I think it really works: CDs, because they are plastic, can get an electrostatic charge on their surface of probably several hundred or thousand volts. When they are spinning, the charge rotates past the laser lens and associated parts. Some of these parts consist of fine electric wires involved in the pickup circuit. My guess is that the spinning electrostatic charge induces small transients in the wiring, and these transients interfere with the bitstream (the musical signal being collected by the laser through the lens). The Bedini Clarifier, in my estimation, may be eliminating or reducing the electrostatic charge. Here is a close-up photo of my top-loading CD transport, showing the CD spindle, the nearby lens, and some fine copper wires (red arrows). The wires are exposed to the spinning electrostatic charge on the CD. I think you might also be able to achieve similar results by cleaning both sides of the CD with a moist cotton ball before playing, and also perhaps with one of the static guns that several websites sell, but I have not tried them. I do have a Bedini, and it does seem to improve the sound quality, although in a subtle way. I wish transport designers would include complete electrical shielding around the pickup circuit, but the total mass may be part of the concern, because servo feedback makes constant adjustments in the tracking.


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Q You said in the Perpetual Technologies review that three 1As could be used to handle the digital outputs from a DD source. How would this be done? There is only one bitstream coming out of the processor isn't there?

A All Meridian processors offer digital outputs.  Once DD has been decoded by the processor, the digital outputs will output a 2-channel S/PDIF. There are 4 S/PDIFs:

1 - Left and Right Front

2 - Center and Sub

3 - Left Surround and Right Surround

4 - Left Side and Right Side

Each S/PDIF is like the output of a DVD or CD player (an RCA digital coax jack for example).  You would connect one P-1A to each S/PDIF. The Meridian processor decodes the compressed bitsream (DD or DTS) and then breaks them out into four pairs of PCM audio data (it would be three pairs in the case of a processor that doesn't have side channels). So, you end up with three digital jacks, each outputting a pair of channels from the 5.1 DD or DTS original, in PCM format. Each Perpetual Techologies P-1A would treat its pair as if it were just a stereo signal coming off your CD player. S/PDIF can handle a maximum of two channels in PCM, up to 96/24. If you want 192/24, then PCM can handle one channel in the bitstream instead of two. For something like a mass market receiver, the decoded digital information is passed to the DACs inside the receiver and then output as 5.1 channels of analog audio. In the Meridian, besides having the analog outputs, the signal is also taken after decoding but before digital-to-analog conversion, and fed to S/PDIF jacks for use with DACs outside the processor (they have digital speakers with DACs inside for use with these outputs).

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Q I would like to ask a question about choosing a digital receiver. Actually, I'm searching for a value receiver which would cost around $400. The nearest that I found is the Pioneer VSX-D509 ($279) with 5.1 channel inputs, Technics SF-DX7 ($388) with 6-Channel Discrete Inputs, and Technics SA-DX940 ($219) with 5.1 channel inputs. I heard from someone that its better to have receivers with 6 digital inputs to enjoy the best DTS and DD surround from DVDs. I don't understand the 5.1 channel inputs and  6-Channel Discrete Inputs very well. Could you please explain it and recommend one of the three receivers above or another one taking into consideration my price range?

A Having a set of 5.1 is the same thing as 6-Channel Discrete Inputs, because 5.1 means five full range channels and the 0.1 channel being the subwoofer, for a total of six channels. The reason your friends suggest having a receiver with the 5.1 inputs is that this will let you play DVD-Audio discs when and if you get a DVD-Audio player, because they will all have a set of 5.1 output jacks to connect to the 5.1 input jacks on your receiver. It won't affect DD and DTS unless you get a receiver that does not have DD or DTS decoding built-in, in which case, you would need an outboard DD/DTS decoder. However, all new receivers these days have DD and DTS decoding. What you might consider is getting a receiver that has a set of 5.1 pre-out jacks, which will allow you to connect an outboard five-channel power amplifier. This will indeed give you better DD and DTS experiences. Make sure the receiver has at least one subwoofer output jack on the rear panel as well. Subwoofers are critical in movies, especially action films. All the receivers in your price range tend to have a similar sound quality. So, just pick one that has an easy to deal with set of controls, including the remote control, and look on the back to see if it has the 5.1 inputs and 5.1 pre-outs I mentioned.

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Q I am inquiring on installing a home theater system for my commercial real estate company here in NYC. Your group was recommended by a consultant here in NY. I need three different systems to choose from. Each should consists of the whole complete theater system including a digital camcorder. Can you recommend where I may obtain these whole package system, as oppose to researching all the necessary components separately? Each package containing total price and warranty info. If you need additional info. let me know.

A The camcorder suggests this will be used to show and sell homes and commercial properties. Wow, this is a far cry from the printed photos I saw when I bought my home. Here are three sets (the warranties differ from company to company, but are about a year in most cases, sometimes several years):

(System 1)

Video: Computer with at least a 500 MHz processor, 128 MB RAM, 18 GB SCSI Hard Drive, and 0.25mm pitch 17" monitor. You probably already have one. A Pinnacle DV-500 Video Capture Card ($900) goes in one of the computer PCI slots. It has Firewire jacks to connect with a digital camcorder, such as the Canon Optura ($1,400). You will need Non-Linear Editing (NLE) software to edit your videos. A good one is ULead MediaStudio Pro 6.0 ($500). If your real estate company wants to have models walking around talking several feet in front of the camera, then get a wireless FM microphone such as the Azden 400 Series (about $600). This will allow your model or spokesperson to wear the wireless microphone as a beltback with a lavalier mic clipped to his or her collar. The receiver plugs into the camcorder. You can get a stereo microphone setup if you like, as well. You can probably show the videos from the computer, including a laptop if it is a fast one. Otherwise, you will want to have a digital VCR to play your video tapes, such as Sony ($2,000). You could convert them to a regular VHS tape or S-VHS tape, but neither of these will be as good as the original Digital Video tape. For a TV monitor, go to Price Club and get a 32" model that has at least one S-Video jack on the back. Different stores have different models, but you should be able to find one for about $700. Use the S-Video connection when playing DVDs, or from the computer, or directly from the camera.

Audio: Toshiba SD-6200 DVD Player ($700), Yamaha RX-V995 Receiver ($1,000), Four B&W DM-602 Speakers ($1,200 for the set), B&W CC-6 Center Speaker ($400), and Velodyne CT-150 Subwoofer ($800).

(System 2)

Video: Same as above.

Audio: Toshiba SD-6200 DVD Player ($700), Onkyo TX-DS989 Receiver ($3,200), Paradigm Reference Series Speakers ($4,000).

(System 3)

Video: Same as above, except substitute High Definition TV such as Toshiba, Sony, Philips, or Panasonic. Size will depend on the room in your office. Price will be about $5,000 to $7,000. This will let you have a non-interlaced video image, and in this case, you should select the non-interlaced feature on the Canon Digital Video Camera when you are taking your videos. It will also let you watch DVDs in a non-interlaced mode, and of course, watch High Definition TV broadcasts.

Audio:  Toshiba SD-6200 DVD Player ($700), Meridian 861 Surround Processor ($10,000), Sunfire Cinema Grand Signature Five-Channel Power Amplifier ($3,500), Four Krix Esoterix I Mark II Speakers ($7,000), Krix Centrix Center Speaker ($700), and Velodyne HGS-18 Subwoofer ($3,000) or M&K MX-5000 Subwoofer ($2,500).

 

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Q First, I wanted you to know I find your website to be one of the best sources for home theatre information anywhere.  I have a couple of questions I hope you can help me with.

For my front speakers in my home theatre I have a pair B&W 604s and a B&W CC6.  I decided to purchase the 602S2 speaker for my surrounds because I was not impressed with the limited frequency response of the DS6 dipole surround (85 Hz to 8 kHz).  I felt full range speakers would take better advantage of the wider frequency range from DD and DTS.  Then the other day I heard that the lowest frequency sent to the surrounds is in the 65 Hz range.  Is this correct and what do you think of full range speakers for surrounds?  

Also, what is your recommendation for speaker placement of monopole surrounds?  The majority of literature I've read deals with dipoles.  What I have seen for monopoles suggests they should be placed in the rear corners of the room.  I am also not sure how high they should be and whether or not they should be tilted down towards the main listening position.  I have a lot of flexibility with speaker location since my theatre is in the basement, and I have plenty of room, so I could put them just about anywhere.  My basement is basically rectangular.

A Most speakers that I have seen for use in the surround positions are full range in the high frequencies (i.e., 20 kHz). It is just that, with old Pro Logic, 8 kHz was about the upper limit for what got sent there. However, with DD and DTS, all the channels, except the LFE (subwoofer), get full range sounds, including low frequencies. Whether or not a particular movie uses that full range depends on the director, but they all are capable of full spectrum sound. So, if you have the room, then get full range speakers all the way around. Obviously, the center channel speaker is limited only by how large a speaker you can fit on top of your TV. The CC-6 is superb, by the way. For the rear, there are so many variables, the only way to really tell is to try various locations out. But, if your speakers are full range, then the corner might not be the best place, since you will get some bass loading there. I would suggest putting them to the sides of your couch and slightly behind, pointing towards the center of the room. After trying that out, you should move things around to see if you like something else better. You are lucky to have so much flexibility, and you should take advantage of that by spending an entire day moving the speakers and trying different locations.

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Q I have an Onkyo Integra M-502 Dual Mono amp which supplies 260 wrms to each channel @ 4 Ohms (safely).  I want to power a sub with it, and am thinking of using a car sub.  I don't think I'm the first.  Subs in mind are the Infinity Kappa Perfect 12 as a set or the Eclipse 88150 DVC 15".  So now to the question.  Are 12" subs really going to be more accurate than the 15"?  There seems to be no end of conflicting info on the matter.  I want to use them for music as well as HT.  Both of the above models are supposed to be very accurate in properly constructed sealed enclosures.

A The differences between car sub drivers and home sub drivers are that the car drivers are usually 4 Ohms impedance and are designed to be put into small enclosures. So, the ones you mentioned should be fine. The smaller the driver, the more easily it can be controlled, because the smaller cone has less mass. However, the smaller the driver, the less air it will move, and if you want loud, deep bass, you want big drivers. On the other hand, if you are going to use two 12" drivers, they should give you all the bass you want. For myself, I would probably use very high quality 18" drivers, such as this one http://www.audioc.com/subs/ACI_drivers/SV18.htm .

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Q I have a 4 year old Sherwin Pro Logic receiver.  Recently, it has begun to turn itself off if the volume is increased beyond a certain point, and I have to tell you this cut-off point is at only very moderate levels (my daughter is getting very frustrated not being able to listen to "Do you know the Muffin Man" and sing along).  Do you have any ideas on what might be causing this?  Also, I have a couple of questions about "clipping" - what is it, how do I know I have it, and at what point do I run the risk of permanently damaging my speakers?

A My guess is that the inside of your receiver is very dirty, and the heat sinks are being prevented from doing their job. So, just take the chassis cover off (don't forget to unplug it first), and dust everything with a vacuum cleaner and the dust brush. Make sure your receiver is in a spot that has plenty of air circulation too. Clipping usually sounds like loud pops or crackles during the music. It is always a danger to speakers, and your tweeter will be the first driver to go if you damage them with clipping. But, I don't think that is what is occurring in your system. You appear to have a heat problem.


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