If you're planning hotel audio infrastructure and have heard the terms "70V" and "8-ohm" without clear context, this guide gives you the practical decision framework. We compare the two systems on the dimensions that matter for hospitality: cable run distance, cost at scale, audio quality, and operational flexibility.
The guide is vendor-neutral. Rafilis makes Rafilis Multizone, which works with either speaker system because the choice is made at the amplifier and speaker level, not in the software. We have no commercial preference; we'll give you the honest comparison.
The technical difference
70V/100V line systems (also called "distributed audio" or "constant voltage" systems) use small audio transformers built into each speaker. The amplifier output is at a high voltage (70V in the US, 100V in Europe — the names are interchangeable in practice for hospitality use). Each speaker's built-in transformer steps the high voltage down to drive the speaker at the appropriate impedance for its power rating.
The result: many speakers can be wired in parallel on a single amplifier line, over long distances, using standard wire.
8-ohm systems (also "low impedance" or "direct-drive") have no transformers. The amplifier directly drives the speaker's natural 8-ohm impedance. The amplifier and speaker are matched directly without intermediate voltage step-down.
The result: very high fidelity at short distances, but distance and parallel speaker count are limited.
What this means for hotels
70V advantages for hospitality
1. Long cable runs without quality loss. A 70V amplifier can drive speakers over 200+ meters of cable without meaningful loss. An 8-ohm amplifier loses signal quickly past 30-40 meters. For hotels where speakers are far from the AV equipment room (beach club, pool deck, distant function space), 70V is the only practical option.
2. Many speakers per amplifier output. A 70V amplifier can drive 30-50 speakers in parallel on a single output. An 8-ohm amplifier typically drives 2-8 speakers per output before impedance becomes a problem.
3. Easy expansion. Adding speakers to a 70V line is straightforward — just connect them in parallel. Adding speakers to an 8-ohm line requires more careful impedance calculation.
4. Simpler wiring. Standard, inexpensive speaker wire works for 70V over long distances. 8-ohm requires increasingly thick wire over distance to maintain low resistance.
8-ohm advantages for hospitality
1. Audio fidelity. No transformer in the signal path means slightly better audio quality, especially in the very low and very high frequencies. Audible? In carefully controlled listening conditions, yes. In a busy restaurant with background music? No.
2. Simpler short installations. A small café with two speakers near the amplifier doesn't need 70V's complexity. 8-ohm is appropriate.
3. Lower per-speaker cost. Commercial 8-ohm speakers don't have built-in transformers, making them slightly cheaper individually.
4. Off-the-shelf consumer compatibility. 8-ohm is the standard for hi-fi and consumer audio. More speaker brands and models are available at 8-ohm.
Where 70V is the right choice for hotels
Almost always. The specific scenarios:
- Multi-zone audio installations spanning more than 50m of cable
- Resort properties with outdoor pool decks, beach clubs, distant restaurants
- Conference centres with many small rooms, each needing audio
- Large hotels where amplifier room is centralised
- Properties where future expansion is likely
This covers ~90% of hotel and venue installations above 30 rooms.
Where 8-ohm is the right choice
- Boutique hotels with 2-4 zones, all within 30m of the amplifier
- Small restaurants with a single zone
- High-end residential-style installations where fidelity matters and distances are short
- Specialty audio rooms (sound check rooms, audiophile lounges)
This covers ~10% of hospitality installations.
Cost comparison at scale
For a 100-speaker installation (typical mid-sized hotel):
| Item | 70V system | 8-ohm system |
|---|---|---|
| Speakers (100 × 6" ceiling) | 100 × €120 = €12,000 | 100 × €90 = €9,000 |
| Amplifiers (need fewer at 70V) | €1,500-3,000 | €4,000-8,000 |
| Speaker cable | €1,500 | €4,500 (heavier gauge) |
| Installation labor | Standard | +20-30% (more complex impedance management) |
| Total | €15,000-17,500 | €17,500-21,500 |
Despite higher per-speaker cost, 70V wins on total system cost for installations over ~30 speakers, primarily through cable and amplifier savings.
Practical considerations
Speaker tap settings
70V speakers have selectable wattage taps (often 0.5W, 1W, 2W, 4W, 8W, 16W). The tap determines how much power that speaker draws from the line. Hotel installations typically use 2-4W taps for ceiling speakers in background music applications.
The math: total wattage of all speakers on a line must not exceed the amplifier's rated 70V output. If you have a 250W amplifier and 50 speakers at 4W each, you're at the limit (200W with safety margin).
8-ohm impedance management
8-ohm installations require careful impedance calculation when wiring multiple speakers. Three 8-ohm speakers wired in parallel present 2.67 ohms to the amplifier — most amplifiers cannot safely drive this. Mixing series and parallel wiring schemes (e.g., 4 speakers in two series pairs, paired in parallel = 8 ohms) is required to maintain safe impedance.
This is why 8-ohm is typically limited to 2-4 speakers per amplifier output in practice.
Mixing 70V and 8-ohm in one property
Some hotels use both systems:
- 8-ohm for the bar (high quality, short distance, 2-3 speakers)
- 70V for the rest of the property
This requires separate amplifiers or amplifier outputs for each system, and clear labelling at the equipment rack. Doable but adds complexity. Most properties pick one system and stick with it.
Recommendation by property type
| Property | Recommended system |
|---|---|
| Café / small restaurant (1 zone, <30m cables) | 8-ohm |
| Boutique hotel (30-50 rooms, 4-6 zones) | 70V (default) or mixed if short distances |
| Mid hotel (50-150 rooms, 8-12 zones) | 70V |
| Large hotel / resort (150+ rooms, 15+ zones) | 70V |
| Outdoor venues (beach club, terrace, pool deck) | 70V (mandatory for distance) |
| Conference centres | 70V |
| Audiophile listening room | 8-ohm |
What software DOES NOT determine
Worth emphasising: your choice of audio control software (Rafilis Multizone or competitors) does NOT determine 70V vs 8-ohm. The software outputs balanced audio to the amplifier; the amplifier and speaker system handle the rest. You can run Rafilis Multizone with either 70V or 8-ohm speaker infrastructure equally well.
Common installation mistakes
1. Underpowering 70V lines. Using a 100W amplifier on 60 speakers at 4W each (240W total) — undercapacity, amplifier overheats and shuts down.
2. Mixing 70V and 8-ohm on the same line. Damages the amplifier or speakers. Always separate the systems.
3. Wrong tap setting per zone. Each speaker can be set to different wattages. Background music ceiling speakers don't need 8W taps — 2-4W is plenty.
4. Too long cable runs on 8-ohm. 50m of standard speaker cable on 8-ohm loses ~3dB of high frequency. Audible. Use 70V for any run over 30m.
5. Not labelling the system at the rack. "Amplifier 3" without indication of 70V or 8-ohm leads to dangerous mistakes during maintenance.
Related reading
- How to plan audio zones for a 100-room hotel — zone planning
- Multi-zone audio for hotels: how it works — full architecture
- Software vs Hardware DSP for hotels — DSP decision
- The complete guide to hotel background music systems — strategic context
The 70V vs 8-ohm question is one of those technical decisions that seems intimidating but resolves cleanly once you know your property profile. For hotels above 30 rooms with multiple zones, 70V is the answer almost always. For very small or very fidelity-focused setups, 8-ohm can win.