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The Bose Lifestyle™ Music System The end of conventional hifi systems? By LEO SIMPSON For quite a few years now, more or less since the advent of the compact disc player, the design of hifi systems has been pretty static. Whether large or small, they have always seemed complicated to the uninitiated and even to those familiar with them. Now that has all changed, with the coming of the Bose Lifestyle Music System. Not only have hifi systems always had lots of controls, for the last 15 years or so they have been ugly black monoliths. And the loudspeakers have been big, or small, black rectangles. No wonder most women don't like hifi systems , even though most like music. Let's face it, most hifi systems are ugly monstrosities. They don't blend with rooms, they dominate them. Now there is the Bose Lifestyle Musi c System, a system that doesn't look like a hifi system at all. In fa ct, it doesn't look like any electronic appliance previously available. As our pictures show, it is a slim polished aluminium case. It opens to reveal a compact disc player and an AM/FM stereo tuner. Having no knobs at all, it is meant to be controlled by the remote handpiece. An RF device rather than using infrared light, it works from anywhere in the home or outside it, with a range of about 30 metres from the music centre. Nor do the loudspeakers look like loudspeakers. They are so small and insignificant that they can be virtually invisible or even completely hidden in most rooms. Yet the loudspeaker system is driven by Is this what you'll be listening to in the future? This is the complete Bose system, to suit two listening zones. The Acoustimass powered woofer and "twiddlers" serve one area while the smaller Roommate-styled speakers would serve another room. 20 SILICON CHIP amplifiers with a total power of 200 watts - loud enough for anyone but seeming to come almost out of thin air. Hifi without controls So this is the Bose Music System, a highly flexible system but lacking many of the controls we have come to expect on hifi systems . For example, there are no tone controls, no loudness switch, no balance control, no source and mode selector switches, no fancy flashing lights - not even a volume control knob. And what about the speakers? How can they get away with such insignificant little stacked cubes? And for that matter, how do they cram 200 watts of power amplifiers into the music centre? They don't. The speakers are a powered version of the Bose Acoustimass 5 this is a satellite cum superwoofer system. We've already stated that the system is meant to be controlled by the remote handpiece but even there it does not have any user facilities for adjusting the tone (bass , treble or loudness) or balance. Instead, the Bose system incorporates automatic loudness compensation, continuously adjusting the bass response according to the sound level. As well, there are preset bass and treble controls on the Acoustimass enclosure. These are set and forget controls which are not meant to be used in everyday listening. In practice, they would be set when the system was installed and then not touched. Twiddlers The satellite speakers are the little stacked cubes. Because they can be angled to alter the sound dispersion and because they handle mostly treble, Bose calls them "twiddlers''. They handle all the signal Spot the speakers in this room. They're up behind the greenery on the room divider. That's the beauty of the Bose system which allows the speakers to be completely concealed if you want. above about 200Hz and are driven by 50 watt per channel amplifiers. The Acoustimass superwoofer is Bose 's double tuned resonant system active equalised and fed by a 100 watt amplifier. The 50 watt amplifiers and 100 watt amplifier are all in the woofer box and it can be hidden almost anywhere in the room. All the sound seems to emanate from the twiddlers, provided you can spot them, and that creates a dramatic impression, especially to anyone familiar with conventional loudspeakers. Different zones A big drawback of current hifi systems is that they only allow one source to be used at one time. So if SEPTEMB EH1990 21 The Bose Music System is intended to be fully integrated with video systems. In this photo, the Bose "twiddlers" are visible but not obtrusive. the compact disc player is being used, the tuner or tape deck can't play. With the Bose system, not only is it possible to listen to two program sources at one time, it is possi- ble to listen to them in different parts of the house. For example, you could listen to the compact disc player in the lounge room while someone else could listen to the AM/FM tuner or watch a video in another part of the house. Both sources in the music centre can be separately controlled with separate or the same RF remote handpiece. This is possible because the Bose system uses powered loudspeakers, either the Acoustimass system already referred to , or smaller powered Bose Roommate style speakers. Any number of powered loudspeakers can be run from the music system, although with two program Bose's remote control can be used from any part of the house or even outside. An RF device, it controls all the facilities on the Music Centre. 22 SILICON CHIP zones, only two program sources can be listened to at one time. Besides the inbuilt compact disc player and tuner, the Bose music system has phono sockets for tape monitor loop, auxiliary and video stereo inputs. The source that most people will note is missing is a conventional turntable. That can still be used but it means connecting a conventional hifi system to the music centre via the auxiliary inputs. First impressions We first saw the Bose Music System at the Australian release on July 19th. Everyone who saw the system came away impressed with the concept. It will radically change hifi systems as we have come to know them. No longer will people be willing to accept a large wall unit or a rack of hifi equipment in their listening rooms. They will not want to look at the gear - it will have to be virtually invisible. So that's the concept of the radical new Bose system. People will love it and it is sure to be imitated on a wide scale by other manufacturers. But is it hifi? You will have to wait till the next continued on page 121 to confirm that the memory chips in the XT or AT were identical, not only in type number but in access time, before you could do any substitutions. Autotransformer convention My thanks to Steve Payor for his clever tip in the June issue [Circuit Notebook) about reconfiguring a power transformer to give a 220 volt AC supply. It has made life easier for my computer monitor. However, I have always understood that the common connection of a step-down autotransformer should be on tlie neutral side. Should not this circuit be revised so that the output voltage is reduced with respect to earth, rather than by raising its neutral above earth? [D. M., Yorkeys Knob, Qld). • It is true that it is customary to wire a step-down autotransformer with the common connection on the neutral side [as shown in Fig.1). However, in this case, Steve Payor has connected the transformer so that the normal secondary winding will be connected to the neutral side and this will reduce the voltage stress on it. This is a good idea because, normally, a transformer has lower rated insulation for the secondary winding. In practice though, the insulation on modern transformers is so good that you could connect the circuit either way without problems. High energy ignition circuit change I want to build the high energy ignition circuit published in the May 1988 issue of SILICON CHIP. Have there been any alterations to the circuit since the time it was printed? (J. S., Preston, Vic). • We do have one recommended change. We suggest that the four 1N4761 75V 1W zener diodes be Increasing the gain of the bowtie array I would like to ask you if you can give me any information in regard to increasing the gain of the Bow Tie UHF Antenna (SILICON CHIP, January 1988), either by increasing the size or by stacking; if by stacking whether vertical or horizontal and how far apart and method of coupling etc. (R. G., Forster Keys, NSW). • Unfortunately, we have no information on increasing the gain of the bowtie array, either by increasing the size or by stacking. That is not to say you can't increase the gain by increasing the size but to do so would mean a complete re-design. You can also increase the gain of bow tie arrays by stacking. In both cases the gain will be increased by the same amount, but changed to 1N5374 75V 5W zeners. There have been a number of instances where the 1W zeners have failed when spark plug leads have been dislodged. Longer messages on Digital Voice Board Recently we purchased a Digital Voice Recorder board as featured in SILICON CHIP. The magazine article implies that the four individual 30 second recorded messages can be chained into one continuous two minute message. The printed matter we have with the kit does not mention any modifications or what needs to be done. How do you do it? (J. P., Shepparton, Vic). • The Digital Voice Recorder board can be chained to provide a continuous message from the four separate memories by closing Sl, S3, S5 and S7 of the DIP switch. This will set the board to playback all four memories in sequence. To record in each memory, press the memory catch switch when LED 1 is on and then the record button. As soon as the record LED extinguishes, the next memory will be if you horizontally stack, the horizontal acceptance angle will be reduced which can be handy in reducing ghost reception. Similarly, if you vertically stack, the vertical acceptance angle will be reduced which can be handy in reducing ghost reflections from aeroplanes (ie, aircraft flutter). The way to connect two stacked antennas is by means of equal length cables which, ideally, should be a multiple of half a wavelength long at the approved frequency of reception. That is about as much as most texts say on the subject but if you stack two high gain antennas [such as our UHF bow-tie array) close together, you won't get much increase in gain. They have to be several wavelengths apart if your are to achieve close to the theoretical increase in gain of 3dB (ie, a power gain of 2). accessed and by again pressing the record button recording can continue. Do this for each memory. When in playback, it will be one long message. Note that there will be a slight sound gap between memories. To fix this, disconnect diode D12 and connect it to pin 8 [the record pin of IC7) instead of pin 9 when recording and back to pin 9 when under playback, using a changeover (SPDT) switch. This will trigger record on each memory automatically in one switch position and automatic playback in the other.~ Bose Lifestyle Music System - from p.22 issue to know all the answers to that question. By that time we will have put a Bose Lifestyle Music System through a battery of tests, objective and subjective. In the meantime, do you want to know the price? It's a lot more than you may have considered paying for a system in the past; around $4600 for the basic system described here. We'll give you the full rundown next month. [.ffl SEPTEMBER1990 121