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Building kits is a great way to save a lot of money with hi fi equipment. In particular you can build speakers which will outperform commercial models costing many times more than the cost of the kit's components. You'll also find here information to help you make up cables, amplifier kits and several other unique products.

In some cases we just describe projects, but wherever possible we will offer a kit of components you can purchase. There are also links to websites where you'll find background information on the various topics.

We are starting off with a limited range, because we like to build and test each kit before offering it for sale. And we will be concentrating on kits that do not require advanced construction techniques or tools to complete.

Hi fi is a great area to experiment, and as your ability to discern sound quality improves you'll find you can hear differences that previously went unnoticed. We've been doing this for nearly 30 years, and still are delighted when a new idea provides an improvement.

We have defined a series of projects which may match up with your own requirements.

Decibel Project 1. Home cinema setup using existing equipment.
When we purchased a DVD player that had a builtin Dolby AC3 decoder and RCA outputs for the 5.1 channels, I wanted to be able to set up a home cinema sound system using my existing collection of amplifiers and speakers. But it wasn't quite that simple - the 4 channel receiver I was using had only stereo inputs so I couldn't use the four channels and have control over the level of each of them. Or if I disconnected the 4 power amp channels from the preamp I had no volume control at all. I also needed another 2 channels of amplification. That was initially provided by an old Leak stereo amp, which does have a volume control.

What I was looking for was a 6 channel volume control, with separate control over every channel. This led to KIT 4, a simple 6 channel passive attenuator, which can be built for about $30.00.

Then I discovered that Silicon Chip magazine published a project in March and April 2002 which also provided a remote control facility. This is KIT 3 - 6-channel remote volume control.

In many cases readers may already have a good stereo amp, if a powered subwoofer is purchased that gives 3 channels, you still need a centre and rear channels. This led to the design of KIT2, basically the same amplifier as KIT1 but in a larger case which has room to include 4 channels of power.

For speakers I built the d'Appolita design published on the Audax website. This is not a cheap option, but the results are superb. The front speakers provide excellent performance for stereo music, and the large subwoofer I built adds an extra dimension to the sound. Only problem was that I needed an active subwoofer crossover to use with normal stereo music. This led me to KIT5, which I built into the 6 channel volume control (KIT 3) and installed a switch so I could switch the front channels between the front L & R signals from the DVD (with the subwoofer getting the LFE signal) or subwoofer enhanced stereo.

This now means I can change from Dolby 5.1 to subwoofer enhanced stereo with a single switch, and control the volume with the remote.

Decibel Project 2. Wireless powered speakers.
The stimulus for this project was a friend whose house construction makes it just about impossible to install wiring between various rooms. So he asked if it was possible to buy wireless speakers. That set me searching, and I found quite a few were available overseas, but almost nothing in Australia.

The original concept was to have speakers with amplifiers inbuilt, and a wireless receiver which would pick up the audio source signal from a transmitter located near the main hi fi centre. In the end I opted for separate items because it allows a great deal more flexibility in the choice of the speakers and power and facilities in the amplifier.

The combination of wireless transmitter/receiver, power amp, and speakers allows high quality music to be produced in any desired location inside, outside, upstairs, downstairs within about 20 metres of the main hi fi setup.

As part of this project I decided to build a powerful compact amplifier to drive the pair of remote speakers (KIT 1). The amp had to be powerful enough to produce a high enough sound level for a party, and clear enough for critical listening. Most power amps do not have source selection or volume controls, but I thought it would be advantageous to at least be able to control the input level. There is actually room in the case for a remote volume control, or to build in the wireless receiver, or fit multiple input sockets and a selector switch, or possibly even a subwoofer crossover (KIT 5).

The speakers for this project could be a variety of sizes. For example I built up the rear speakers of the Audax Home Theatre System and these have proved very handy to use outside, hanging from chains under the patio. Great for outdoor barbecues and parties. I also have a pair of floorstanding two way speakers which are omnidirectional because the drivers face upwards and inwards - these work very well as rear channels as well as giving a spacious room-filling sound in their own right.

For the transmitter/receiver the simplest solution is the 2.4Ghz Wireless A/V System which is one of our Innovative Products. There are now small transmitter and receiver modules available which can be built into projects.

 By the way these wireless powered speakers can also be used as the rear channels in a home theatre setup when you don't want to have the problem of speaker cables from the front to the rear.

Decibel Project 3. Versatile 2 way floorstanding speakers.
These have a number of design parameters. They are large enough to be floorstanding (ie don't need stands) and have excellent bass performance from their 8" woofer/midrange. They are also efficient enough to be coupled to a modest component mid fi system. (I used a 25W per channel Sony stereo to test this out). Construction of the cabinet is simple, requiring no special tools. The price is very reasonable for the sound they are able to produce. They also can handle the 50W RMS power output of the Decibel Stereo 50 power amp. This is a great first project for someone wanting to "get into hi fi".

This 3rd project is in limbo at present (September 2004), I hope to resurrect it over the next few months. If you have SUSCRIBEd to our mailing list you'll see an announcement via a newsletter.