what's the difference?

i'm looking at specs for the new Emu 1820m.

below are the specs. the common mode rejection always seems to be
many db less than the crosstalk db. i don't think i understand
"common mode rejection".

to my slightly-trained eyes, the overall specs look nice. would an
experienced person agree?


Sample Rates: 44.1, 48, 96, and 192 kHz, from internal crystal or
externally supplied clock (no sample rate conversion).

Bit Depth: 16 or 24 bits

PCI Bus-Mastering DMA subsystem reduces CPU usage

Zero-latency direct hardware monitoring w/effects

Analogue line inputs-6

Type: servo-balanced, DC-coupled, low-noise input circuitry

Level (software selectable):

* Professional: +4dBu nominal, 20dBu maximum (balanced)
* Consumer: -10dBV nominal, 6dBV maximum (unbalanced)

Frequency Response: +/- .05dB, 20Hz – 20 kHz

THD+N (1 kHz at -1dBFS): -110dB (.0003%)

SNR (A-weighted): 120dB

Dynamic Range (1 kHz, A-weighted): 120dB

Stereo Crosstalk (1kHz at -1dBFS): -115dB

Common-Mode Rejection (60Hz): 40dB

Analogue line outputs-8

Type: balanced, low-noise, 3-pole low-pass differential filter

Level (software selectable):

* Professional: +4dBu nominal, 20dBu maximum (balanced)
* Consumer: -10dBV nominal, 6dBV maximum (unbalanced)

Frequency Response: 0.0/-.35dB, 20Hz – 20 kHz

THD+N (1 kHz at -1dBFS): -105dB (.0006%)

SNR (A-weighted): 120dB

Dynamic Range (1 kHz, A-weighted): 120dB

Stereo Crosstalk (1 kHz at -1dBFS) -115dB

Mic pre and line inputs-2

Type: TFPro™ combination microphone preamp and line input

Frequency Response: +0.8/-0.1dB, 20Hz – 20 kHz

Stereo Crosstalk (1 kHz min gain, -1dBFS): -120dB

Line Input:

* Gain Range: -12 to +28dB
* Max Level: +17dBV (19.2dBu)
* THD+N (1 kHz at -1dBFS, min gain): -94dB (.002%)
* Dynamic Range (A-weighted, 1kHz min gain): 100dB
* SNR (A-weighted, min gain): 100dB

Microphone Preamplifier

* Gain Range: +10 to +50dB
* Max Level: -12dBV (-9.8dBu)
* THD+N (1 kHz at -1dBFS, min gain): -95dB (.0018%)
* SNR (A-weighted, min gain): 100dB
* Input Impedance: 330 ohms
* Common-mode Rejection Ratio (60Hz): 80dB

Phone input stereo

Type: RIAA equalized phono input

Frequency Response: +/-0.5dB, 50Hz – 20 kHz

THD+N (1 kHz, 10mV RMS unbalanced input): -76dB (.015%)

SNR (10mV RMS unbalanced input, A-weighted): 90dB

Stereo Crosstalk (1kHz at -1dBFS) : -80dB

Maximum level:

* Professional: 80mV RMS
* Consumer: 20mV RMS

Input capacitance: 220 pF

Input impedance: 47K ohm

Digital I/O

S/PDIF:

* 2 in/2 out coaxial (transformer coupled)
* 2 in/3 out optical (software switched with ADAT)
* AES/EBU or S/PDIF format, switchable under software control

ADAT:

* 8 channels, 24-bit @ 44.1/48kHz
* 4 channels, 24-bit @ 96kHz (S-MUX compatible
* 2 channels, 24-bit @ 192kHz

Firewi

* 400 Mbps 1394a port (6-pin)
* Compatible with DV cameras, storage peripherals, etc

Midi:

2 in, 2 out