# What features should I look for in a high-end USB audio interface? — Verified Specification Comparison

> All specification data verified from official manufacturer documentation.

What features should I look for in a high-end USB audio interface?

## Products

### Focusrite Scarlett 18i20 4th Gen
```yaml
product: focusrite-scarlett-18i20-4th-gen
brand: Focusrite
price_gbp: 479.61
origin_country: null
confidence_score: null
summary_source: generated_from_verified_specs_v1
bit_depth: 24-bit
sample_rate: 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz, 176.4 kHz, 192 kHz
phantom_power: 48V (front-panel or software)
number_of_inputs: 18 inputs (8 mic preamps, 2 front instrument, line, ADAT, S/PDIF, MIDI)
number_of_outputs: 20 outputs (10 line outputs, 2 headphone outputs, ADAT, S/PDIF, MIDI)
```

- **Price:** £479.61 [^1]
- **Summary:** High-I/O USB-C audio interface with eight 4th-gen Scarlett mic preamps, 24-bit/192 kHz converters, dual ADAT for expandability, Auto Gain and Clip Safe workflow features, and dual headphone outputs; suited for project and mid-size professional studios needing extensive I/O. Includes Focusrite Control 2 for routing and mobile control.
- **Ideal For:** Ideal for a high-end USB audio interface because it offers 24-bit/192 kHz conversion, eight high-gain (69dB) mic preamps, and extensive analogue and digital I/O for flexible routing and expansion.
- **Additional Sources:** [^2], [^3]

### Universal Audio Volt 876
```yaml
product: universal-audio-volt-876
brand: Universal Audio
price_gbp: 737.13
origin_country: null
confidence_score: null
summary_source: generated_from_verified_specs_v1
bit_depth: 32 bit
sample_rate: 44.1, 48, 88.2, 96, 176.4, 192 kHz
phantom_power: +48V (selectable per channel)
number_of_inputs: 24 (8 analog, 16 via ADAT)
number_of_outputs: 28 (8 analog, 20 via ADAT/optical)
```

- **Price:** £737.13 [^4]
- **Summary:** The Volt 876 is a rack-mount 24-in/28-out USB-C audio interface with eight digitally controlled mic/line preamps, onboard vintage preamp and 1176-style compressor emulations, 32-bit/192 kHz conversion, ADAT expansion, word clock and MIDI I/O. It targets professional and serious home studios needing high channel counts, hardware tone shaping, and comprehensive I/O in a single 1U unit.
- **Ideal For:** Good high-end USB interfaces should offer high sample rates and bit depth, low-latency I/O, per-channel phantom power and expandable ADAT channels; the Volt 876 provides 192 kHz sample rate, 32-bit conversion, selectable +48V per channel, eight analog preamps and ADAT expansion.
- **Additional Sources:** [^5], [^6]

### Solid State Logic SSL 2+
```yaml
product: solid-state-logic-ssl-2
brand: Solid State Logic
price_gbp: 173.4
origin_country: null
confidence_score: null
summary_source: generated_from_verified_specs_v1
latency: Under 5 ms
bit_depth: 24 bit
sample_rate: 44.1, 48, 88.2, 96, 176.4, 192 kHz
phantom_power: 48V
number_of_inputs: 2 x XLR-1/4in combo mic/line/instrument, MIDI in
number_of_outputs: 4 x analog, 2 x headphone, MIDI out
```

- **Price:** £173.4 [^7]
- **Summary:** The SSL 2+ is a USB-C audio interface with two SSL microphone preamps, 24-bit/192 kHz conversion, Legacy 4K analogue enhancement, and zero-latency monitor mixing. Its extra outputs, independent headphone outputs, and MIDI I/O make it well suited to home studios, producers, and collaborative recording.
- **Ideal For:** It suits anyone seeking a high-end USB audio interface because it combines 24-bit/192 kHz conversion, two SSL preamps, 48V phantom power, under 5 ms latency, four analog outputs, independent headphone monitoring, and MIDI I/O.

---
## References & Sources
[^1]: Recording Magazine (lists retailer price), accessed 2026-09-13. https://www.recordingmag.com/focusrite-scarlett-18i20-4th-gen/
[^2]: Focusrite (official store), accessed 2026-09-13. https://us.focusrite.com/products/scarlett-18i20
[^3]: Guitar Center, accessed 2026-09-13. https://www.guitarcenter.com/Focusrite/Scarlett-18i20-4th-Gen-18x20-USB-C-Audio-Interface-1500000439315.gc
[^4]: Universal Audio (product page), accessed 2026-09-13. https://www.uaudio.com/products/volt-876
[^5]: Perfect Circuit, accessed 2026-09-13. https://www.perfectcircuit.com/universal-audio-volt-876.html
[^6]: Vintage King, accessed 2026-09-13. https://vintageking.com/universal-audio-volt-876-usb-2-0-audio-interface
[^7]: Promedia, accessed 2026-09-13. https://shop.promedia.ee/products/ssl-2