Home Entertainment Blog Archive
Brought to you by your friendly, opinionated, Home Entertainment and Technology writer, Stephen DawsonHere I report, discuss, whinge or argue on matters related to high fidelity, home entertainment equipment and the discs and signals that feed them. Since this Blog is hand-coded (I like TextPad), there are no comments facilities. But feel free to email me at scdawson [at] hifi-writer.com. I will try to respond, either personally or by posting here emails I consider of interest. I shall assume that emails sent to me here can be freely posted by me unless you state otherwise.
This archive is for an uncertain period commencing Thursday, 19 February 2004
Many pieces have been written by many people attempting to explain, in terms accessible to the non-technical, what anamorphic widescreen is all about. I've had a bash at it myself here and here and, to some extent, here.
But this slide show Web site offers an exceptionally accessible explanation, well illustrated, that ought to be clear to anyone.
Thanks to my brother Mark, whose own Web site is full of excellent photographs of Canberra.
Rod, mentioned in the post below, has also suggested I include 'dialog normalization' in the Dictionary of Home Entertainment. Good point, and it was something I shouldn't have overlooked, so here it is. Naturally this required some other additions, so in went metadata and dynamic range control. Plus I've added slightly to Dolby Digital, and corrected a mistake (I had said it was originally developed for film, but of course it was originally developed for digital TV, but became famous through film).
My treatments of these subjects in the dictionary are necessarily short, but there's some interesting Webbed stuff. In particular, this Secrets of Home Theater and High Fidelity piece is excellent while this SMR Home Theatre A/V Magazine piece also provides useful background, and raises the interesting issue of calibration.
If you read formal treatments of setting up home theatre systems, you will find that they always ask you set the channel levels using the test tone for an indicated 75dB on your SPL meter. This is something I never do. I usually use 70dB or 80dB. Why? Because the good old Radio Shack meter has +6dB on the extreme right of the scale, so if you set the dial to 70 and try to get everything at 75, the meter needle will spend a lot of its time pushed against the stop on the right hand side. I suppose it can take it, but I believe in respecting equipment (I have two of these meters, the first one I purchased some time in the 1970s and it still works fine!)
Also, because I don't think that calibration to an absolute volume level is especially useful. For me the important thing is to have the channels calibrated properly relative to each other. What level I actually watch a movie on depends upon my mood, the circumstances and the equipment I'm using. If properly calibrated to an absolute level then, as the SMR piece makes clear, program peaks may reach 105dB. Actually, that's 105dB per channel! Let's do some arithmetic. If I'm reviewing some DynAudio speakers (which, as a rule, I simply love for their sound), I have to take into account their lower than average sensitivity. They typically come in around 85dBSPL (1 metre, 2.83 volts average pink noise bandwidth limited to 500-2,000Hz). Let's say that the receiver I'm using can deliver 100 watts per channel. At my listening position of 2.7 metres from the front speakers, the volume for one watt (which is what 2.83 volts into eight ohms is) is actually less than 85dB. One hundred watts is 20dB more than one watt. So there's no way that this system can reach the 105dB peak. Absolute calibration is not a good idea in such cases.
Or I might be watching a movie with gear that has plenty of headroom (say some Klipsch speakers with a sensitivity of 96dB driven by a Sony digital receiver producing 170 watts per channel), and the guy next door is mowing the lawn. So I turn it up louder than the absolute calibration level. Or I might be watching late at night and I need to have it down (two of my daughters came rushing out to my backyard office the other night from their rooms on the other side of the house, worried about the shooting and screaming they heard -- but it was just me playing the start of Runaway Jury).
The SMR piece also mentions some calibration problems with some test DVDs. I did a quick check on some of mine. I agree with the piece that all calibration tracks really ought to be set for the official calibration level of -31dBFS (0dB dialog normalization). Here's what I found:
- Video Essentials: -27dBFS (-4dB)
- The Ultimate DVD Platinum: -31dBFS (0dB)
- DVD Spectacular (both program and test tones): -31dBFS (0dB)
- Pearl Harbor (Region 4) THX Optimizer and program: -31dBFS (0dB)
- Alien (from the new Quadrilogy set) (Region 4) THX Optimizer: -31dBFS (0dB), but -27dBFS (-4dB) for the movie
- Manhunter (R1) THX Optimode and program: -27dBFS (-4dB)
Rod, the chap who maintains the extremely useful
Chopping List Web site (on movie censorship), asks:
The question relates to video switching. I currently use a Marantz AV9000
HT pre-amp as a processor.
It has video switching for various formats, including composite, S-video
and component. I've learnt that video switching may reduce audio
performance, due to those circuits running at "higher frequencies".
While reading your informative A/V blog yet again, I was reminded of a
question which you may be able to help me with. I have done some web
searches but have not found any comprehensive info.
Ah hah, here is where I get to be heretical again. If the equipment manufacturer is not entirely incompetent, it matters not a whit that the A/V processor or receiver has video switching in the same box.
What damage can the video signal do to the audio signal? The transit of the signal could generate high frequency fields that in turn induce currents in the audio circuits. Solution: shield these sections of the circuits from each other. Could there be interference back through the common power supply? Sure. There certainly is (except where the switching is passive). As there is if the boxes are completely separate with their own power supplies. The important question is the level. Totally insignificant. Not measurable, not audible.
Marantz is most certainly not totally incompetent.
The video circuits do indeed run at higher frequencies. The bandwidth of a PAL or NTSC composite video signal is around 5MHz or a bit more (it's considerably higher for high definition video). I haven't checked out the power vs frequency spectrum of such signals, but let us assume that it is roughly even (ie. it's very wide bandwidth pink noise), then the fact that it is high frequency is good. A video signal runs from virtually DC up to that 5-ish megahertz, so only a tiny proportion of it is in the audio bandwidth. Even if you take the audiobandwidth to extend to 100kHz, that still means that only 2% of the low voltage (1 volt p-p) low current video signal could map over onto the audio circuits.
In any case, there are other high frequency signals within an A/V processor -- necessarily. The incoming digital audio signal, the DSPs, the DACs all run at greater than 1MHz. Once again, this isn't a matter of concern, just careful design.
Sony Australia says that it has stopped importing and selling CRT computer monitors. From now on, it's LCD all the way. The reason?
Compared year on year, value-wise the LCD market has grown by 73% whilst the CRT market has decreased by 38%.
According to GfK independent research statistics, in Australia the LCD market has grown by 183% by volume (2003:2002), at the same time as the CRT market has decreased by 11%.
In other words, they are selling a lot more LCD monitors and fewer CRT monitors. And while the retail prices of both are falling, those of CRT monitors are falling faster than those of LCD monitors.
It may take another couple of years, but I suspect that the big players in TVs will be shifting this way too (although the replacements for CRTs will be both LCDs and Plasmas).
Having just read this Blog entry from the erudite 2Blowhards on the wonder of black and white cinema, I feel rather inadequate. I prefer colour in general, and clearly I haven't educated myself enough about the mood differences generated by different cinematic techniques. But part of the reason for that is that for me they frequently don't bite. Issues of tone and texture do not make a lasting impression on me, whether on screen or in music. It seems that they do for others.
For me the main game is what is being represented: the characters, the plot. (In the case of music, it's the melody, harmony, rhythm and dynamics, not the texture of the orchestration -- Just yesterday I listened to Glenn Gould's rendition of Liszt's piano transcription of Beethoven's 5th Symphony, even though I have a couple of orchestral versions. The piano, and Gould's idiosynchratic style, bring out much for me.)
In any case, a great deal of black and white movie making prior to, say, the mid-50s was not for artistic reasons but for commercial. Colour was more expensive, and so wasn't used unless the producers judged that there would be a reasonable return on investment (Rebel Without a Cause, for example, commenced shooting in black and white, but then was re-shot in colour when the producers decided that it was going to be bigger than they had anticipated.)
That, of course, is a far cry from recent movies where black and white has been chosen on purpose.
Australia is an odd market for home entertainment equipment. We are small (20 million) but the market here has mixed and matched the standards used in the US and Europe, each of which are huge (300-ish million). One example is that we use the PAL TV system that is widespread in Europe, rather than the NTSC system. But the majority of DVD players sold here have component video outputs rather than the SCART RGB outputs common in Europe.
With new products we often get the Europeanised versions. So most standard definition digital receivers have SCART outputs, and quite a few DVD recorders are also European oriented.
The big players, like Panasonic, Pioneer and Philips, usually perform some localisation of their products, but many others don't. So when I was recently reviewing some DVD recorders, I applauded the inclusion of the somewhat user-friendly G-Code* timer recording system on models from Panasonic and Pioneer, and was slightly critical of its absence on the Toshiba D-R1.
Only slightly, because I personally don't find using G-Code much more convenient than simply keying in the time, date and channel for timer recordings. I prefer to allow a little slack at the top and tail of a programmed recording, just in case the TV station isn't running exactly to schedule.
However, my criticism of the Toshiba was wrong it turns out. It has a European timer recording convenience called Showview, and I am now informed that Showview and G-Code are one and the same, differing only in name. So if you're a G-Code fan, don't let the absence of the G-Code logo put you off. Just enter the same code into Showview.
* In the G-Code system, rather than entering the start and stop times and channel for the program you want to record, you just key in a seven digital number printed in the TV program guide. This maps across to these parameters, entering them for you. You must, of course, have your TV stations numbered in accordance with the way the G-Code system expects.
Yesterday I received the most recent edition of Sound and Image which, as usual, contains a number of my articles. Amongst others it has my rave review of the Harman Kardon DVD 30 DVD video/audio player. I like this player very much. So much I bought the review unit.
But, I find long term use reveals weaknesses in my review methodology. It would be nice to use each piece of equipment in a leisurely way for a couple of months, but then the throughput of work would be a tiny fraction of what it is and the living I make, such as it is, would tip over into true pauperhood. So I go for the main game: checking the things it is supposed to do, with an emphasis on those things that separate it from the pack.
In this case, my focus was on the DVD 30's sub-$1,000 price and real, honest-to-goodness ability to properly process DVD Audio surround tracks. This it does superbly, providing real
bass management (complete with a somewhat adjustable
crossover frequency) and real
time alignment). Since the few other DVD Audio players on the market that provide both these essential capabilities cost at least twice as much, you can see why I was impressed.
However daily use has revealed two problems. One is minor, and is to do with the programming of the unit. It seems that it does not always check the disc identifier when you switch it on. So let's say you're playing a CD one evening and decide, half way through, it's time to go to bed. Being lazy, rather than pressing Stop twice and then putting the unit in standby, you just put it straight into standby. Next morning, you decide you're in the mood for something different. So you start up the unit by pressing the Open button, change to a different CD, and press Play. The unit starts playing the CD at the point (ie. the time from the beginning of the disc) it was up to the previous night on the other CD. In other words, it doesn't recognise that the CD is different and reset its counters accordingly.
Far more important is the sound quality of CDs from the analogue output. Something is wrong with it. When you play back CDs using the analogue outputs, every 17 to 19 seconds it produces a short noise, like a digital hiccup (ie. it seems to skip a few samples or something, producing this noise). This noise is quite loud enough to be clearly audible on most CDs. Yet it does not do this if you feed out the PCM signal to an external decoder.
I've asked the distributor about this, but there has been no reply yet. If anyone else has experienced this, I'd be interested in hearing from you.
As an aside, when I was recently reviewing new all-digital Sony STR-DA5000ES home theatre receiver, I failed to notice a useful feature: the composite video input signal is converted and made available on both the S-Video and component video outputs, and the S-Video input signal is likewise made available on component video. Saves a lot of TV input switching. This feature is becoming increasingly wide-spread, now also available in models from Onkyo and Yamaha.