In this blog post I review the SB Audience Nero-12MWN400D 12" Mid-Bass Woofer. This new series from SB Acoustics includes an extensive feature list:
- Proprietary cone paper material with manila pulp
- Strong neodymium motor
- 3" voice coil with APC (Advanced Polymer Coating)
- Interleaved Sandwich Voice Coil technology
- Cast aluminum chassis
- Minimum damping fiber glass voice coil former
- Copper sleeve for low inductance and reduced distortion
I'm using this woofer is a custom mono speakers for a customer which I featured here.
I also did a close up video of the driver here.
Here are some additional photos on this driver.
Test Setup
I setup the measurement outside to eliminate the affects of the room. Show below is my close mic setup for distortion, burst decay, step response. All other measurements were done at 1m mic distance. All measurements are ungated.
Here are some other details related to my test setup.
- Hypex FA501 plate amp (no filtering)
- Chord Mojo DAC
- Dayton UMM-6 USB Mic
- Dayton DATS V2 Tester and software
- ARTA 1.9.4 measurement software
- Generic Decibel meter for setting levels
- Laptop
Measurements
Frequency Response
The below frequency response was take at 1m. The drivers were mounted in my No.1432 bass enclosure which is reflex tuned to 58Hz. The enclosure is very heavily constructed from 24mm thick baltic birch plywood. The slot ports help to structurally reinforce the cabinet. The resulting F3 is 50Hz.
Below is the frequency response near field (ground plane).
Impedance
Below is the resulting impedance curve in my reflex cabinet.
Step Response
The SB Audience Nero-12MWN400D shows a very fast step response at 6.7ms with a very steep rise time (almost vertical).
Burst Decay
The burst decay shows a very clean result from 50Hz-2kHz where the normal breakup occurs.
Distortion
Below is the harmonic distortion at 90dB at 1 meter mic distance. 
Below is the harmonic distortion at 100dB at 1 meter mic distance.
ARTA introduced new functionality with their latest software version 1.9.4. Specifically the multitone intermodulation distortion test has improved visibility by creating overlay curves that follow the test results. Fixed Overlay 1 (FOV1) follows the top of the multitone peaks. Fixed Overlay 2 (FOV2) follows the distortion side band products. You can create multiple overlays as you increase SPL. Below is the screen capture that shows the green multitone signal along with the green distortion products -50 to -60dB below the fundamental tones. The three sweeps represent my three SPL levels of 80dB, 90dB, and 100dB. 
ARTA now allows you to remove the green spectrum results and simply show the overlays (see below). As you can see IMD starts to rise in a non-linear fashion when I jump from 90dB to 100dB.
As you can see from the test results the driver is -60dB down at 200Hz at 80dB SPL. This is a very good result. IMD remains low even at 90dB SPL however it starts to rise at 100dB (-46dB down). So essentially this driver rewards in a domestic listening (audiophile) setting by at least have the capacity to provide transparent sound quality at normal listening levels.
Group Delay
Phase Response
Subjective Listening
Playing Daft Punk 'Get Lucky' outdoors provided extremely detailed and powerful bass. This is an impressive driver. Switching to John Mayer's live performance at Crossroads Tour provided very snappy bass. This is not a gentle or soft sounding driver. I delivers exceptional dynamics when called on. Overall I would recommend this driver for your future project.