Installer Guide
70V vs. 8-Ohm Commercial Audio: which one belongs in your facility?
If you're specifying background music for a spa, salon, dental office, or any small-to-medium commercial space, you'll run into two distribution standards: 70V constant-voltage and 8-ohm low-impedance. They were designed for different jobs. Picking the wrong one costs you fidelity, install time, and money.
The short version
When each system makes sense.
70V constant-voltage
Built for very long cable runs and large speaker counts — stadiums, warehouses, paging systems in big-box retail. A central amp steps the signal up to 70 volts; a transformer on each speaker steps it back down.
- Best when runs exceed ~150–200 ft per speaker.
- Best when you need 30+ speakers on a single line.
- Trades fidelity for reach — the transformers roll off bass and clarity.
8-ohm low-impedance
The same standard a home stereo uses, scaled for commercial distribution. No transformers in the signal path — the amplifier drives the speakers directly through a distribution module.
- Ideal for spas, salons, dental offices, small clinics, restaurants.
- Cleaner, fuller sound — full-range music, not just intelligible paging.
- Simple 4-wire install. A capable owner can run it without a low-voltage contractor.
Head to head
Five things that matter in the real world.
| Factor | 70V constant-voltage | 8-ohm (Fundamental Audio) |
|---|---|---|
| Audio fidelity | Transformers roll off low end; designed around speech intelligibility. | Full-range music reproduction — what guests actually hear in a treatment room. |
| Install complexity | Each speaker needs a matching transformer tap; mis-tapping cooks the amp. | Four conductors from the head unit to each speaker. No tapping math. |
| Best for cable runs | Long runs — 200 ft and beyond, dozens of zones. | Short-to-medium runs typical of a 1,500–15,000 sq ft facility. |
| Scalability per channel | Engineered for 30–60+ speakers on one line. | Up to 20 amp/speaker sets per zone on the Fundamental system — sized for the buildings we serve. |
| Total installed cost | Amp + per-speaker transformers + skilled labor. | Lower hardware cost, simpler labor — often DIY-able. |
Why we build 8-ohm
Most commercial spaces don't need 70V — they need music that sounds good.
70V systems exist for a reason — paging a 200,000 sq ft warehouse is a real problem. But that's not what's happening in a day spa, a tanning salon, or a dental practice. Those rooms are 200–2,000 sq ft each, and guests are paying for an experience. Thin, transformer-coupled audio undermines it.
The Fundamental Audio Distribution System is our single-channel 8-ohm head unit. Class-D amplification, 4-wire distribution, up to 20 amp/speaker sets per zone. For multi-zone facilities, the ADS family adds independent volume control per room while keeping the same low-impedance signal path.
We've been shipping these from Gilbert, AZ since 2002. They're in salons and spas you've walked into without knowing — which is the point.
Common questions
FAQ
- Can I retrofit an existing 70V install to 8-ohm?
- Usually yes — the speaker wire is the same; you remove the transformers and add a distribution head unit. We've done it for facilities that wanted better music without re-pulling cable.
- What about really long cable runs?
- For runs over ~200 ft per speaker, 70V is still the right tool. For a typical spa or dental office where the head unit lives in a closet and rooms are within 100–150 ft, 8-ohm is the better answer.
- Is 8-ohm loud enough for a commercial space?
- Yes. The Fundamental System drives up to 20 speaker pairs at background-music levels appropriate for treatment rooms, waiting areas, and retail floors. It's not designed to fill a stadium — and shouldn't be.