DEQX PreMate D/A processor/digital equalizer Manufacturer's Comment

Editor: DEQX Speaker calibration requires anechoic (no reflection) measurements often made in listening rooms for convenience. But room effects must be removed to allow the speaker's own phase and frequency response to be calculated and adjusted.

The DEQX speaker and measurement microphone is positioned to maximize the time before the microphone picks up the first reflected sound occurring after the speaker's direct sound. DEQX-Cal software then removes the reflected sounds at the operator's discretion.

Since every installation is unique, the process is usually performed by our experienced on-line DEQXpert installers, so no manual is required. Kal used the manual with little or no help from us and we applaud him for the effort. We agree with Kal that the nearly 200-page software installation manual takes some getting used to, but really, in most cases you won't need to look at it. Even if you're as capable and technically minded as Kal, we urge our customers to use free DEQXpert support.

BTW, the PreMate provides two kinds of room calibration and Kal used the ParaEQ described in the manual. Convolution-based room calibration is also available in certain configurations that can be implemented by a DEQXpert installer or dealer.

With regard to JA's comment regarding very low level noise (-110 dB) at around 11kHz, we don't believe its effects are now audible as we've added an additional power supply regulator to reduce it further towards low noise limits.

Thanks again—Kim Ryrie, DEQX

COMPANY INFO
DEQX Production
4/18 Lexington Drive
Bella Vista, NSW 2153
Australia
(61) 2-9905-6277
ARTICLE CONTENTS

COMMENTS
JR_Audio's picture

Hi Kal

Great review and description how to work on the Speaker and the Room Optimization separately with DEQX PreMate. I know it is a bit difficult to validate, but this point make a bit difference between different “room optimization” hard- / soft-ware.

Lately I have done also some measurements on different room optimization hardware (2 of the 4 based partly on your recommendations over the last years) and separation speaker from room optimization separates the men from the boys.

With the MLSSA measurement system you can chose different lengths of the adaptive time window (where the lengths changes with time (and so the resolution over frequency)) and so you can differentiate between the results of the speaker optimization from those of the room “optimization”.

Looking forward seeing you at the CES.

Juergen

Timbo in Oz's picture

Does it have a simple switch option for that?

DEQX's picture

Yes - There is a simple software switch that allows each of the four outputs (2 x main speakers and 1 or 2 optional subwoofers) to be individually phase inverted and auditioned in real-time.

corrective_unconscious's picture

"However, the DEQX Calibration app (v.2.93), running on a Windows XP machine, indicated that 192kHz data were downsampled to 96kHz, and 176.4 down to 88.2."

"(I haven't shown the 192kHz response, as it was identical to that at 96kHz, which suggests that the DSP signal path operates at a maximum rate of 96kHz.)"

Does this mean only the signal processing part of the component downsamples, or is this indicating that the DAC downsamples also? (Or you don't really have a true bypass option, do you?)

In either case, assuming I have understood this at a basic level, I am surprised that such an expensive component would be doing this in any of its modules. The specs seem to claim the unit accepts high resolution recordings through at least some of its digital inputs. Are those claims misleading?

John Atkinson's picture
Quote:
Does this mean only the signal processing part of the component downsamples, or is this indicating that the DAC downsamples also? (Or you don't really have a true bypass option, do you?)

Though the PreMate will accept 176.4 and 192kHz datastreams, it appears that it downsamples them to half those rates before the data are presented to the DSP section, then finally the DAC. So no, there is no true bypass.

Quote:
In either case, assuming I have understood this at a basic level, I am surprised that such an expensive component would be doing this in any of its modules.

Running powerful DSP at 4Fs sample rates is very consuming of resources, so this compromise is not uncommon. It is likely that the benefits of the DSP correction outweigh the potential drop in sound quality due to the downsampling.

John Atkinson
Editor, Stereophile

corrective_unconscious's picture

Good thing the high end consumer is getting more and more choices of hi rez music. And hi rez formats!

It is hilarious, benefits of DSP or not, imo.

(Thanks for the clear explanation and confirmation.)

lhissink's picture

Life becomes more interesting when the speaker system is a Larsen 8 that are specifically designed to work with the floor and rear wall. My system is in a temporary location but DEQX did a preliminary speaker correction limiting the correction window from 20 to 800 Hz. But I have to wait until May or June 2015 before any more comments can be made.

And great review, and agree with the documentation - it requires deep study and time to fully utilise the software.

w1000i's picture

If possible I hope to see a review for wyred4sound DAC-2 DSDse :)

X