Monday, 25 February 2013

MEASUREMENTS: Behringer DEQ2496.

<Originally posted Feb 17, 2013 on Squeezebox Forum>

This weekend, I decided to hookup the Behringer DEQ2496 digital EQ processor to the test gear and see how this measures. Normally, this unit is set up to provide room EQ via a digital loop with the Transporter so I've rarely had a listen to the analogue outputs.

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Internal DAC is the AKM AK4393, the little brother of the Transporter's AK4396. About 6 months ago I actually hooked the DEQ4396 to the main system to have a listen and I must say that I had a difficult time telling the difference AB'ing it with the Transporter (when I normalized the volume on both) so I have some idea that it likely measures quite well.

The set up for this: Transporter --> TosLink --> Behringer DEQ2496 --> XLR --> E-MU 0404USB --> AMD Phenom X4 laptop. All plugged in to the Belkin PureAV PF60 power conditioner.

Here are the RightMark results (the DEQ2496 only has XLR output):
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Not bad. The DEQ is capable of ~18-bit dynamic range. As you can see, the Transporter measures better with an extra (literal) "bit" of dynamic range. Here's the DR graph:
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I noticed that for the 24/96 test condition, the Transporter's frequency response is significantly flatter than the DEQ2496. Differences are essentially ultrasonic in any case.
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Finally, the jitter FFT plot (24/48 signal)...
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This is where I'm "disappointed" with the DEQ2496. It appears to have poor jitter rejection at least with the TosLink interface. The reality of course is that in real music, I still can't say I can hear this.

Conclusion:
For a product that costs ~$300, the DEQ2496 remains a great bargain. The RightMark results are good but it's prone to (TosLink) jitter. Subjectively, it sounds good on my system compared to the Transporter despite the Transporter's much better jitter results (again, does jitter really matter in a perceptible way unless it's crazy high?). Nonetheless anyone buying this unit is in it for the digital EQ, not likely the DAC quality...

BTW, the DSP chips are dual Analogue Devices ADSP-21065L 32-bit SHARC chips (66MHz, ~200MFLOPS). ADC chip: AKM AK5393VS.

2 comments:

  1. Have you ever written about noise spectrum level versus bit depth, dither waveform, FFT points and window?
    Thank you very much.

    ReplyDelete