Digital Consumer Audio System

Jed Margolin

I want a Digital Consumer Audio System (DCAS) that has the following:

1. Hard Drive (80 GByte or higher)

2. CPU/RAM/etc. No x86s, please. They come with too much baggage.

3. CD-ROM Drive

4. AM/FM Tuner

5. Flash Memory Slots (Compact Flash, SD Flash, etc.)

6. Two 50 Watt Audio Amplifiers

7. Wireless Networking built-in

8. Inexpensive display screen (such as Liquid Paper)

9. Remote Control (with display) using the Wireless Networking protocol.

This is what I want it to do:

1. Play CDs (CD-ROM, CD-R, CD-RW) with the following formats: CD Audio, WAV, MP3, OGG, etc.

2. Play files from the Hard Drive.

3. Transfer files from the CDs while they are playing.

4. Convert files between formats.

5. Record from the AM/FM Tuner (with a Timer) onto the Hard Drive.

6. Record from Line-in and Microphone inputs.

7. Transfer files from Hard Drive to Flash Memory.

        a. You can rip CDs for your portable MP3 player.

        b. You can record Coast-to-Coast AM at night,  transfer it to Flash Memory,
            and listen to it during the day at work.

8. You can program the Timer as an Alarm Clock to wake you up at a selected time with an alarm sound, a musical selection, by turning on the radio, or by playing a selected message. Possibly, a market will develop for wake-up messages similar to ringer tones for cell phones.

9. The Wireless Networking capability allows you to transfer music files between your PC and your DCAS.

10. The Wireless Networking capability allows you to use the DCAS hard drive as Network Attached Storage (NAS) for backing up your PC.

11. The Wireless Networking capability allows you to transfer all your files to your next DCAS unit when your current DCAS unit becomes obsolete in 18 months.

Other Requirements:

1. It must be small enough for a bedroom.

2. During operation, It must be quiet. One way is to have enough internal memory to keep 1 hour of material, so that the hard drive can be powered down most of the time.

3. No Microsoft software of any kind. (Linux is probably ok.)

4. All User Interfaces must be easy to use and not require PC-like skills.

For example:

a. In Tape Recorder mode it should be as easy to use as an old reel-to-reel tape recorder.

b. In Tape Recorder mode there must be a rotary knob (such as an opto pot with no stops) for selecting edit points in the sound file.

In old reel-to-reel tape recorders editing was done by manually moving the tape past the playback heads. The user was able to control the tape speed and find the desired edit point. Then the tape was marked with a grease pencil to indicate where the tape would be cut with a razor blade after being moved to the editing block. (If you have never edited a tape this way, it is a lot more precise than you might think.) I want an electronic version of this. An advantage of an electronic version is that a number of edit points and be marked and the final result auditioned before making anything final.

5. Because it has Wireless Networking capability, Security is a critical concern.

a. You want to protect the data files used as Network Attached Storage.

b. You want to protect the music files because of copyright issues.

c. You also have to protect the User Programmed data.

You don't want malicious code to turn the unit on at 3 am and start swearing at you. (If that's what you really want, you can always program it to do that yourself.)

To this end, the unit must be made so that System Files cannot be modified, even if it means putting the OS in ROM (Masked ROM or EPROM; not Flash ROM.) This means that the software must be fully debugged before the unit is shipped. None of this "Ship it now and have the customers download the working version from the Internet as soon as they take the unit out of the box" crap.

Protecting the User Programmed Data means that it cannot be modified through the Wireless Network. If that requires special hardware, then so be it.


1. An external AM/FM Tuner (with suitable antennas) that can be mounted outside the house. The advantage of being outside is that it can be located to receive radio stations more effectively. It will also be away from all the interference-generating equipment that is becoming so prevalent inside houses.

It would be controlled through the WIreless Networking protocol.

It would use solar cells to recharge a rechargeable battery so that it would be completely wireless. Alternatively, the battery can be recharged with a small wind generator using non-conductive blades so it does not interfere with the RF signals. The wind-generator can be designed as decorative lawn art.

2. An external satellite radio receiver similar to the AM/FM radio described above.

3. A Multi-track Recording Console that uses the Wireless Network protocol to use the DCAS for storage, editing, and playback. It will also be able to use the DCAS processing power.

4. The Flat Panel DIsplay can use a touch screen for the User Interface.

5. The Flat Panel Display can be used to display the audio being played back in several formats, such as:

    a. WaveForm (oscilloscope mode)

    b. Volume bars

    c. Spectrum Analyzer

    d. Old style analog VU meters (for us old guys)

6. CD Burner

7. DVD Drive/Burner for audio CDs and data storage.

8. Additional amplified speakers (using Wireless Network protocols) to support 5.1 sound, etc.

9. Headphones that access the DCAS through the Wireless Networking protocol.

10. Phono Preamp inputs for people who want to preserve the material on their old records.

11. The unit can be made to look like an Old-Time Radio (OTR) and implement the methods taught in U.S. Patent 5,978,488  Simulated AM Radio. ("A realistic illusion of listening to an actual AM radio is produced by providing a number of audio program signals and by simulating the process of tuning across the radio dial where each station is playing a different program".) The User specifies which audio files to use as the programs. Alternately, an OTR pod can be made that uses Wireless Networking to access the DCAS's storage and computing  resources.

Here is a Replica Radio that has been modified to send its dial position to a PC using an RS-232 interface. (A simple counter measures the frequency of the Local Oscillator.) Audio from the PC is sent to the Radio's amplifier so it is controlled by the Radio's volume control and comes out the speaker.


Instead of the RS-232 interface it would use the Wireless Network protocol.

A number of Radio Pods (OTR or modern) can be used independently.

And Finally

The DCAS must not require PC skills because when it comes to doing pleasant useful things, PCs really suck.

Jed Margolin
San Jose, CA
April 25, 2004

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Copyright 2004 Jed Margolin