Installation
Common AV Installation Mistakes
Most AV failures are not caused by faulty equipment, they are caused by installation shortcuts. This guide covers the mistakes we most often find when called to repair or upgrade someone else's work, so you can avoid them on your next project.
Mistake 1: Ignoring power quality
Kenyan mains supply can carry surges, brownouts and phase imbalance, particularly in older buildings or areas with unstable grid connections. Installing amplifiers, mixers or LED processors directly onto unprotected mains without a surge protector or automatic voltage regulator is one of the fastest ways to destroy equipment. A single surge event can burn out an amplifier's power supply, a repair that often costs more than the protection would have.
Rule of thumb
Any installation over 200,000 KES in equipment value should include line conditioning or a UPS, even if the budget was not planned for it. The cost of one damaged amplifier usually exceeds the price of protection.
Mistake 2: Undersized or mismatched cabling
Speaker cable gauge
Using thin speaker cable over long runs causes voltage drop, reducing power delivered to the speaker and increasing amplifier strain. As a general guide, runs over 15 metres for 4-ohm loads should use at least 2.5mm² cable, and runs over 30 metres should step up to 4mm².
Signal cable routing
Running unbalanced audio cable alongside mains power cable in the same conduit introduces hum and interference. Balanced XLR cable resists this far better, but even balanced runs should keep at least 30cm separation from power cabling wherever possible, more where cables must cross at right angles rather than parallel.
| Issue | Symptom | Fix |
|---|---|---|
| Thin speaker cable | Weak bass, distorted highs on long runs | Upsize gauge based on run length and load |
| Power/signal cables bundled | Audible hum or buzz | Separate conduits, cross at right angles |
| No strain relief | Intermittent connection, connector failure | Cable clamps and service loops at termination |
| Mixed cable brands/impedance | Inconsistent tonal response | Match cable spec to system design |
Mistake 3: Mounting without load calculation
Speakers, projectors and LED panels are frequently hung using whatever bracket was in stock rather than one rated for the actual weight plus a safety margin. Industry practice requires a minimum 10:1 safety factor for suspended loads above people. Skipping this calculation has led to serious accidents in venues that cut corners on rigging.
Mistake 4: Ignoring room acoustics
Installing a technically excellent sound system in a room with hard, parallel, reflective surfaces guarantees poor intelligibility regardless of equipment quality. Basic acoustic treatment, or simply angling speakers to avoid direct reflection off glass and tile, is often skipped because it is not a line item on the equipment quote.
Mistake 5: Poor DMX and control wiring
Lighting installations often fail because DMX cable is confused with standard microphone cable, which lacks the correct 110-ohm impedance for reliable data transmission over longer runs. Daisy-chaining more than 32 fixtures on one DMX universe without a splitter also causes signal degradation and flickering fixtures.
Mistake 6: No labelling or documentation
An installation without labelled cables, a rack diagram and a settings backup becomes very expensive to service later. Technicians end up tracing cables blind, adding hours of billable time to even simple repairs.
Mistake 7: Skipping commissioning and testing
Walking away after physical installation without running the system at full load, testing every input and checking coverage across the room leaves problems for the client to discover during their first real event. Commissioning should include a signal test on every channel and a walk-around listening or viewing test.
A basic quality checklist
- Surge protection or UPS installed on all sensitive equipment
- Cable gauge matched to run length and load
- Signal and power cables separated
- Rigging load-calculated with adequate safety factor
- DMX runs use proper 110-ohm cable with termination
- All cables labelled at both ends
- Full system tested under load before handover
Why hiring qualified installers matters
Many of these mistakes come from treating AV installation as pure wiring work rather than a discipline that combines electrical safety, acoustics, rigging and signal theory. Tiffy G Supplies installation teams follow documented commissioning checklists on every project, precisely to avoid the failures described above.
Frequently asked questions
Why did my speakers stop working after a power outage returned?+
Sudden voltage spikes when power is restored after an outage can damage amplifier power supplies. Installing a surge protector or automatic voltage regulator prevents this and is a common gap in budget installations.
Can I run speaker cable and mains cable in the same trunking?+
It is not recommended. Running them together increases the risk of audible hum from electromagnetic interference. Use separate conduits or maintain physical separation where they must run in parallel.
How do I know if my rigging is safe for a hanging speaker?+
Check that the bracket, chain and mounting point are each rated for at least ten times the suspended weight, and have the installation inspected by a qualified rigger before the speaker is used over an audience area.
What causes flickering DMX-controlled lights?+
Flickering is usually caused by using the wrong cable type, exceeding the recommended fixture count per DMX universe, or missing termination at the end of the data line. A DMX splitter and proper termination resolve most cases.
Is professional installation worth the extra cost over DIY?+
For systems above roughly 300,000 KES in equipment value, professional installation protects that investment through correct load calculation, cabling and commissioning, and it typically pays for itself by avoiding early equipment failure.