Focusrite Clarett+ 8Pre review and test – professional rackmount recording interface

Maxim Liadov

Readers have already met the smaller Focusrite Clarett+ 2Pre from the professional Clarett range updated in 2021. The plus sign marks new electronics, a change needed by almost every manufacturer relying on AKM converters. Britain's Focusrite now uses Cirrus Logic converters, from its Crystal Semiconductor division. Specifications have improved, and sound reaches a very high professional studio level.

Here are the specification changes. Figures are identical for the 2Pre, 4Pre and 8Pre:

Parameter	Clarett USB	Clarett+
Input dynamic range	118 dB	118 dB
Input THD+N	-107 dB	-110 dB
Output dynamic range	118 dB	124 dB
Output THD+N	-103 dB	-106 dB
Headphone output dynamic range	115 dB	118 dB
Headphone output THD+N	-101 dB	-104 dB

Owners of the earlier non-plus interfaces have little reason to replace them. New buyers choosing between generations can confidently select Clarett+. Can these official figures be trusted? Our measurements confirm them. More importantly, subjective sound quality is very high. The attractive price makes Clarett+ accessible to many musicians. Choose by channel count because electronics and sound are the same across the range. The larger 8Pre does add a few useful details.

First, rack mounting keeps most cabling behind the unit. Smaller models place microphone sockets on the front, creating more visible cables. Second, only the 8Pre has multi-segment input meters; the 2Pre and 4Pre have green/red gain-knob LEDs. Both 4Pre and 8Pre provide two headphone outputs. Front combo sockets serve microphone/guitar/line channels 1/2. Hardware buttons activate phantom power in groups of 4 inputs. The mixer selects line/guitar mode and AIR processing. Focusrite says the ISA preamp-emulation mode has improved in Clarett+.

Monitor volume for outputs 1/2 uses a digital encoder with an absolute knob position. The knob has a position mark and end stops, while level changes digitally over a 128 dB range in 1 dB steps. Adjustment was easy. The mixer slider follows the knob and cannot be moved with a mouse. Physical position preserves the chosen level without storing it in non-volatile memory, even after unexpected power loss. This excellent design is absent from budget interfaces.

The rear has analogue I/O: 10 balanced TRS outputs and combo XLR/TRS microphone/line inputs. Digital connections include optical and coaxial S/PDIF, with ADAT operation available. MIDI I/O is also present. USB-C connects to any USB 2.0/3.0 computer port. Supplied Focusrite cables include a long standard USB 2.0 cable and a short USB-C cable for laptops.

The attractive red aluminium case is a Focusrite trademark. Metal knobs have non-slip texture and turn smoothly with light resistance. Everything is functional and well considered. The Clarett+ 8Pre has an internal 30 W power supply, more convenient than the smaller models' external adapters. It accepts 100–240 V AC.

The digital section is unchanged. A separate digital board with two XMOS chips handles USB and channel mixing. This separation helps measurements and sound quality.

High-quality integrated microphone preamps use American THAT 1583 chips, offering low -129 dBu EIN and a wide low-distortion gain range.

New two-channel Cirrus Logic CS5381 ADCs specify 120 dB dynamic range and -110 dB THD+N. These converters often appear in high-end studio equipment.

New two-channel CS43198 DACs have impressive 130 dBA dynamic range and -115 dB THD+N. The chip datasheet gives more precise limits: guaranteed dynamic range is 124 dBA, with 130 dBA typical; guaranteed THD+N is -109 dB, with -115 dB typical. Even so, the figures exceed the earlier Clarett converters. Numbers alone do not prove better sound, but the combined changes bring progress. NJM4556AL headphone amplifiers are sufficient for sending a backing track to performers.

Drivers work well in Windows 10 and Windows 11. We tested the latest Windows 11 version.

All Clarett models share the same control panel. It offers a hardware mixer and the useful option to bypass it entirely for direct playback. Alongside analogue inputs, the mix can include 8 ADAT channels, each with metering and volume control. Unneeded channels can be hidden with the cross button.

The buffer-size panel also switches internal/external synchronization and shows clock status. This, together with digital channel expansion, supports studio integration.

Measured round-trip latency at a 64-sample buffer and 44 kHz is 7.9 ms, typical of XMOS devices. The Clarett buffer panel reports exactly the same value.

ASIO diagnostics

RMAA measurements

Device under test	[ASIO] Focusrite USB ASIO
Operating mode	24-bit, 44 kHz
Audio interface	ASIO
Signal path	Line output
RMAA version	6.4.5 PRO
20 Hz–20 kHz filter	YES
Signal normalization	YES
Level change	0.0 dB / 0.0 dB
MONO mode	NO
Calibration signal frequency, Hz	1000
Polarity	Correct/correct

Frequency response variation (40 Hz–15 kHz), dB	+0.01, -0.03	Excellent
Noise level, dB(A)	-120.0	Excellent
Dynamic range, dB(A)	120.0	Excellent
Harmonic distortion, %	0.00049	Excellent
Harmonic distortion + noise, dB(A)	-102.1	Excellent
Intermodulation distortion + noise, %	0.00079	Excellent
Stereo crosstalk, dB	-120.2	Excellent
Intermodulation at 10 kHz, %	0.00174	Excellent
Overall rating		Excellent

Detailed RMAA results at 24-bit/44 kHz.

The 8Pre measures slightly better than the smaller models. We did not reach the published figures because that requires the same unusual 6.2 V RMS (+18 dBu) signal level. We measured at 4 V RMS, producing slightly lower figures. Results are excellent nevertheless.

Sound

We liked the new Clarett's line-output sound very much. It is significantly better than budget Scarlett models and comparable with top-level rackmount recording interfaces. The headphone amplifier is a possible criticism: it is decent but simpler than the excellent line outputs. It is suitable for sending a backing track to performers.

We connected a Neumann TLM 103 condenser to assess preamp recording quality and Air. Focusrite redesigned Air for Clarett+. It switches input impedance to 2.2 kohms and adds a 4 dB treble lift. Air uses hardware to emulate classic ISA 110 microphone preamps from Focusrite studio consoles used on thousands of hits.

Recording quality proved very high. The first three passages in the illustration have no processing; the next three use Air. Gain remained unchanged. Air significantly increases signal level and EQs the recording, making it brighter, as the spectrogram shows. Hardware processing is useful for immediate output without plug-ins, such as live work or streaming.

For further processing, included software offers Antares Auto-Tune, Brainworx bx_console Focusrite SC to emulate the classic ISA 110 module, and Red Plug-in Suite models of the Red 2 EQ and Red 3 compressor.

Conclusions

The Focusrite Clarett+ 8Pre suits a permanent commercial studio needing 8 rackmount microphone preamps. Electronics and sound meet a high professional standard. ADAT expansion allows integration with existing equipment. Its price per channel is among the best on the market. For fewer channels, consider Clarett+ 2Pre or 4Pre, which have equivalent electronics and sound quality.

Note. This is an adapted machine translation into English. It follows the “In simple terms” approach. Read the original article at https://prosound.ixbt.com/interfaces/focusrite-clarett-8pre-plus.shtml.