Why are the requirements for AES higher than those for DMX?

Why are the requirements for AES higher than those for DMX?

1. Higher Operating Frequency

The operating frequency of AES is significantly higher than DMX512. This requires faster signal rise and fall times, which must be paired with low capacitance.

2. Strict Capacitance Metrics

Capacitance is a strict, hard metric. AES requires much lower capacitance than DMX512.

National standard specifies is 43 pF/m (Though this is somewhat conservative; in practice, below 56 pF/m typically works perfectly).

3. Characteristic Impedance

Although the recommended impedance for DMX512 is 120 Ω, it offers high tolerance—110 Ω cables can readily be used as a substitute. (Furthermore, the equipment itself often does not strictly measure at 120 Ω).

AES3 and DMX512 Technical Specifications:

To achieve 50 Mbps/6 MHz, or long-distance 250 kbps transmission, it must be used of Polyethylene (PE) or Foamed Polyethylene (FPE) as insulation.

Thus, once a digital cable achieves a capacitance below 56 pF/m, it becomes broadly compatible with all three standards.

To the extent permitted by a reasonable budget, maximize backward compatibility up to AES-grade in our future product development.

On cable specification sheet and marketing labels, products should be named in a way that:

1. Performance compliance.   2. Well-known to the public.   3. Effectively enhances the value of the product.

Most people associate AES with high quality, leading to a higher perceived value.

It is highly recommended to standardize the product label as "AES/DMX DIGITAL CABLE" .

Forbidden to label as standard microphone cables or analog signal cables.

Q: Why the technical requirements of AES (Digital Audio) are higher than DMX512 (Lighting Control)?

A: While AES and DMX512 cables look very similar and both use a 110-ohm impedance standard, digital audio requires much higher signal quality than lighting control.

Core Differences

• Bandwidth and Speed: AES/EBU carries high-resolution digital audio, requiring a high bandwidth of 6MHz or more. On the other hand, DMX512 runs at a fixed speed of 250kbps, which requires very little bandwidth.

• Error Tolerance: DMX512 is highly error tolerance. If a tiny bit of data is lost, it only causes a tiny flicker in the lights that the human eye can barely notice. However, if an AES signal error, it immediately causes loud pops, clicks, or a complete loss of sound.

• Interference and Jitter: AES is extremely sensitive to timing errors (Jitter). Because of this, AES cables must have very low capacitance to keep the digital signal sharp and clean. DMX512 is much more relaxed when it comes to perfect timing.

Usage Recommendations

• Using AES cables for DMX512: Yes. They are fully compatible and work perfectly.

• Using DMX512 cables for AES: Not recommended. Some cheap DMX cables do not have precise impedance control. Using them for audio can easily cause noise, clicks, or audio dropouts.