Blackstar Polar 4

POLAR: Blackstar's "amp" approach applied to recording

With the POLAR series, Blackstar transfers part of its guitar amplification expertise into a desktop-format studio audio interface. The POLAR 4 is positioned as the most versatile version for those who want to multiply simultaneous recordings (multiple guitars, vocals, amp mics, synths, or drum machines) while maintaining a familiar playing feel. The goal is clear: to reduce typical friction encountered when plugging a guitar into a conventional interface by offering a responsive, "forgiving," and enjoyable input to control.

Who is it for and what studio uses?

The Blackstar POLAR 4 is aimed at guitarists recording at home as well as creators needing a complete interface for producing, streaming, or editing content. Its 4 mic preamps and 48 V phantom power allow recording vocals, acoustic guitar with a mic, miked amps, or a small multi-mic setup. The 2 headphone outputs facilitate sessions for two (musician + engineer, vocal/guitar duo, interview), while the loopback function simplifies recording system audio (streaming, app audio capture, tutorials).

Key features: playing, levels, monitoring, and control

FET inputs + "Enhance": more feel, less gain stress

The heart of the POLAR 4 lies in a FET input stage designed to handle and enhance signals from instruments, pedals, and microphones. Activating "Enhance" introduces a network of components in the signal path to emulate the behavior of a "tube"-style guitar amp input: you get more response, character, and a more natural feel under the fingers. On the instrument inputs, "Enhance" has another major benefit: digital clipping is avoided, limiting ruined takes due to unwanted saturation and allowing level adjustment as you would on an amp preamp.

"Enhance" also useful on vocals and line sources

On mic and line inputs, "Enhance" provides natural clarity and brightness, especially appreciated on vocals and acoustic guitars. This approach can also reduce the need for an external DI or additional preamp to get a guitar signal ready to use immediately in the mix.

Accurate monitoring and modern workflow

The POLAR 4 offers a monitor output and two headphone outputs with independent controls, convenient for adjusting a comfortable level without affecting speaker volume. The POLAR Control software allows management of levels, panning, and monitoring routing, enabling quick adaptation of the setup for vocal takes, guitar re-recording, or multi-source sessions. Finally, the MIDI In/Out connectivity helps centralize a master keyboard, control surface, or expander without multiplying adapters.

Technical specifications

Sampling frequency	192 kHz	Headphone outputs	Yes
Max resolution	24-bits	Nominal mode power consumption (Wh)	5 W

Type	4-channel USB audio interface (desktop format)	Line inputs	4
Simultaneous I/O	6 x 6 (including loopback inputs)	Line outputs	2
Loopback	yes	MIDI I/O	yes
A/D conversion resolution	24-bit / 192 kHz	Frequency response	20 Hz to 20 kHz +/-0.1 dB
Supported sample rates	44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz, 176.4 kHz, 192 kHz	Dynamic range	109 dB (A-weighted)
Connectivity	USB Type-C	THD+N	-101 dB (-103 dB A-weighted), 0 dB gain, 950 mVrms, bandwidth 20 Hz to 24 kHz
Protocol	USB 2.0	EIN noise	-121 dBu (A-weighted)
Bus-powered	yes (960 mA)	Maximum input level	2 dBu
Phantom power	yes, 48 V	Gain range	53 dB
Power supply	USB 960 mA; external (optional) 4.8 W	Impedance	3.3 kOhms
Accessories	USB A to DC cable, USB A to C cable	Maximum output level	12.8 dBu
Number of mic preamps	4	Maximum output power	85 mW at 33 ohms; 66 mW at 300 ohms
Mic inputs	4	Analog-to-digital converter	THD+N -100 dB; dynamic range 114 dB
Instrument inputs	4	Digital-to-analog converter	THD+N -100 dB; dynamic range 114 dB