Home Page | About Me | Home Entertainment | Home Entertainment Blog | Politics | Australian Libertarian Society Blog | Disclosures

Home Entertainment Blog Archive

Brought to you by your friendly, opinionated, Home Entertainment and Technology writer, Stephen Dawson

Here 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, 28 October 2004

Changing servers - Saturday, 27 November 2004, 2:50 pm

This Web site is now located in the United States on the servers of Hosting Matters. Previously it was here, in Australia, with Bigpond Hosting. The service from the latter was excellent, but it is simply much, much cheaper ($US11 vs $AUS66) for much greater bandwidth (19GB vs 2GB) to go offshore. I hope that the service remains as good there.

Subwoofer or receiver crossover? - Monday, 15 November 2004, 11:43 am

Peter has written with the following question:

I bought a Yamaha RX-V450 receiver matched with Polk RM6000 speakers and Polk say to wire the speakers through the subwoofer and not use the subwoofer outlet from the receiver. Encel store say to use a subwoofer cable and set all speakers to small. What do you think?
This type of question comes up from time to time, and the answer is that it all depends on the receiver.

In general, it's best to use the home theatre receiver's crossover for bass, because this can operates at line level (and, in many cases, in the digital domain). Such crossovers are easier to implement, and are less like to audibly degrade the sound than a passive, speaker-level crossover in a subwoofer.

But there is a problem with subwoofer/satellite systems. Small satellites will often be pretty useless for producing sound below around 200 hertz. Home theatre receivers with fixed subwoofer crossovers use 80 hertz, which means that there will be low output in the octave between 100 and 200 hertz.

An increasing number of receivers allow the crossover frequency to be changed. If there's a setting of 200 hertz, this should be selected and the speakers wired up conventionally. Otherwise, wire the front two satellites through the subwoofer. When setting up the receiver, tell it that the centre and surround speakers are 'small', the front stereo speakers are 'large', and that you don't have a subwoofer.

Note, though, that even with this wiring scheme, any bass between 80 and 200 hertz that's on the centre or surround channels will not be properly reproduced. Only Bose, I think, provides crossovers for all five or six channels in its subwoofers. So, really, the best solution is to choose a receiver with a flexible bass crossover in the first place.

Digital TV bitrates in Canberra - Tuesday, 2 November 2004, 2:42 pm

Vince writes:

Could you place (or give a link) on your blog the local TV stations bit rates that I have variously seen in your articles to the Canberra times?
Why not? First, though, I should note that the following figures were derived from some ad hoc recordings I made of digital TV broadcasts between September and November this year. There's no guarantee that they'll be the same next month. Indeed, the rates could conceivably be changed on a daily basis: higher rates in the evening and so forth.

The figures were obtained simply. Just record a chunk of a broadcast using a Topfield TF5000PVRt digital TV receiver, then look at the information it provides: program length in minutes and file size in megabytes. Divide the latter by the former and make appropriate adjustments to convert to megabits per second, and you have the answer. The figure includes the audio, the subtitles and any data validation/decoding material

By way of comparison, DVD's have a top rate of just under 10 megabits per second (Mbps), and of the 500-ish titles I've measured, the average for a movie ranges from a high of 8.84Mbps (The Day the Earth Stood Still) to a low of 2.8Mbps (the Force Video version of Metropolis) The great majority are in the range of 4 to 7 Mbps.

Finally, all these come from the Tuggeranong retransmission tower in the South of Canberra. No telling what the figures may be elsewhere.

ChannelDescriptionMinutes measuredBitrate (Mbps)
ABC TV CanberraMain transmission channel for ABC TV in Canberra. Note that there are two audio streams on this station: MPEG and Dolby Digital.2436.73
ABC TV 2This, and ABC TV 3 and 4, all simply replicate ABC TV Canberra, minus the Dolby Digital audio.656.26
ABC HDTrue high definition, 1080i video.6814.2
ABC DiG RadioNo picture, just two channel MPEG audio at, seemingly, around 300kbps.130.31
PRIME CanberraMain transmission channel for Prime TV in Canberra, our Channel 7 affiliate.748.18
Prime View 2This, and Prime View 1, are only occassionally utilised. During the Olympics one of these showed the action in a statistics/info box. Right now both these stations are showing the aftermath of the Melbourne Cup horse race, exactly the same as on PRIME Canberra. Normally, though, these are simply blank, aside from some text referring viewers to the main station. These figures are for when that was the case. During the Melbourne Cup broadcast, the bitrate was the same as on the main Prime station.641.72
SBS DIGITAL 1Main transmission channel for SBS TV in Canberra. Note that there are two audio streams on this station: MPEG and Dolby Digital.804.79
SBS DIGITAL 2Secondary transmission channel for SBS TV in Canberra. Mostly carries foreign news services.1203.48
SBS EPGSo-called Electronic Program Guide. In fact, it is merely a non-interactive sequence of graphics/text stills with news headlines and information about forthcoming programs. It carries a musical accompaniment.471.87
SBS HDThis is SBS' so-called High Definition station. It meets the government legal definition by virtue of being 576p (progressive scan), but in reality is not truly high definition. It carries the same programming as SBS Digital 1587.89
SBS RADIO 1No picture, just two channel MPEG audio at, seemingly, around 160kbps.200.16
SBS RADIO 2As per SBS Radio 1270.17
SC10 CanberraMain (and only) channel for Southern Cross Capital 10, Canberra's Channel 10 affiliate.5226.22
WIN TV CanberraMain channel for WIN TV, Canberra's Channel 9 affiliate.1147.04
WIN TV HDWIN High Definition (1080i) service. Last time I checked, this was a loop demo tape.6112.16

In case you're wondering, no the Topfield won't display high definition broadcasts. But it will record the bitstream, so the figures for the three HD stations are more or less valid.

Quality Chain Store Staff - Thursday, 28 October 2004, 1:22 pm

I generally recommend that people do their home entertainment shopping at specialty stores, rather than chain or department stores. Two reasons: the former generally have more knowledgable staff, and the latter generally do not have higher end equipment.

But the former reason doesn't always hold. During my HDMI cable search I got into conversation with one of the sales guys at Harvey Norman in Philip, ACT. This fellow turns out to be an enthusiast himself, has been in sales in this field for several years, and knows rather a lot. So if you're confused and Harvey Norman stock is more in your price range than hi fi shop equipment, go there and ask for Stan.

HDMI woes resolved - Thursday, 28 October 2004, 12:46 pm

HDMI output socket That picture to the right is the HDMI output socket of the very fancy Krell Showcase DVD. A little oddly, this doesn't actually have HDMI out installed as standard. It's an option, but the distributor put it in at my request, because I suggested that it would be difficult for my review to say nice things about the picture quality if it was restricted to mere analogue output.

So the DVD player turns up, and I already have the new Panasonic PT-AE700E DVD player ($3,899 - 3 x 1,280 x 720 pixel LCD panels) which has a HDMI input. And there I am without a HDMI cable.

So the search begins, towards the end of last week. Harvey Norman at Fyshwick? No HDMI cables there. Nor at Duratone Hi-Fi. Nor at JB Hi Fi. Nor at Millennium Audio Visual. Nor at Dick Smith Powerhouse. Nor at Jaycar. Nor at S I Computer Products.

In the end, I left a call with Convoy International, the Australian distributor for Monster Cables. On Monday, before they'd called me back, I went into Harvey Norman at Philip for another reason (cheap DVDs -- Harvey Norman is getting rid of their stock at huge markdowns -- not enough money in them I was told) and checked out the cables since I happened to be there. Voila! Monster Cables galore! Including, incredibly, HDMI cables, DVI cables and even the HDMI to DVI and vice versa adaptors.

I bought an adaptor, but balked at the cable: $AUS369 for two metres. JB Hi Fi had mentioned that Pioneer Electronics here sells HDMI cables (sensible, since they sell both HDMI source and display devices), so I rang my contacts there and they sent me a beaut five metre cable.

This will all change, I expect. HDMI will take over the A/V interconnect field over the next few years. It's one cable for video and audio. Both are uncompressed digital. It will simplify connections incredibly. And the plugs themselves are wonders of design. They are compact, slide in and out easily, yet hold firmly and resist being pulled out of shape by the weight of the cable.

Of course, we still need some home theatre receivers to provide HDMI switching, but surely these can't be too far off. My prediction: in five years even cheap receivers will provide HDMI switching, and cheap HDMI cables will be easy to get ahold of.

But that's in five years. For now, HDMI is hard to find, but worth it if you do. (This different mix of equipment confirms my previous tests.)