Accuphase DG58 Necessity or Novelty

[apdoc2004]

Hi everyone,
This is my first post on audioaficionado. I have been following the Accuphase thread with keen interest. I am very intrigued by the Accuphase DG-58 digital voicing equaliser. I would love to know the results when it is used as a room correction device. I did read earlier that Masterlu (Ivan) was experimenting with it. Any updates?
I would love to hear from anyone who has experience with the DG-58 or the previous generation DG-48. How does it compare to the DEQX or McIntosh MEN220 products. Is it easy to use and are the results sonically impressive?
Many thanks

[Mattia]

Hi apdoc2004,
I am currently waiting for the DG-58 I ordered some weeks ago. Hope to have it in a month or two.

When I'll receive it, I'll compare the Accuphase correction to my current Dirac Live correction (in a humble miniDSP 22D).
I think some comparisons with other products are needed for the DG-58. I am sure it is a wonderful piece of hardware, but it would be nice to put it a bit in perspective.

I will also compare the DAC section of the DG-58 to the DC-37 I am also waiting for. In case the DC-37 proves markedly superior (blind test oblige) I'll keep it, if not, I have a friend interested in buying it, so no problem

[Masterlu]

Anshul... Welcome!

[apdoc2004]

Hi Mattia,
I eagerly await your comparison of Accuphase DG-58 with other solutions such as Dirac live.
Hi Ivan,
Thanks for the warm welcome!
Anshul

[nvp]

Hi Matia, I have actually compared the Minidsp DDRC-22D with the DG-48 in my system a few months ago. The dutch importer has demonstrated the unit in my home. However, I do not quite know what to make of the results.

First, the guy has come with two very dubious RCA digital coaxial cables, i.e. one was 3-4 meters long while the other cable was half a meter (or less) long. I do not think either of the two cables was a dedicated digital cable. (I specifically told the guy to bring two dedicated digital coax cables as I do not have such cables but he did not considered that it is important...)

Second, some of his measurements seemed very sloppy. During one of the (side) measurement his body was blocking the sound coming from one of the speakers, while for a different (side) measurement he litteraly placed the mic behind my coach - again there was no direct path between speakers and mic. (When I have pointed this out to him he said that the side measurements are less important...)

Now regarding the obtained "results", IMO the two correction algorithms did a similar good job. They both have improved significantly the quality of the bass and also the soundstage and stereo image. I have preferred the DG-48 as it sounded a bit fuller. Dirac live produced a thinner sound (i.e. less bass and slightly more details) even when the guy tried to replicate in Dirac the correction curve I use in Accuphase.

I was rather proud (and relieved at the same time) to hear that the DG-48 was slightly better, but I was also happy to hear that my extremely sensitive (and thus revealing UNO) did not picked up any noise whatsoever from the MiniDSP unit (which was connected into the PS-1220 unit).

I hope you can provide some feed-back Matia. Do the results yielded by Dirac Live depend on the quality of the side measurements and coaxial digital cables?

[Mattia]

Hi nvp,
thank you for your input!

First of all, I too confirm that the miniDSP 22D doesn't pick up any RF noise and has a very, very low noise floor.

The 22A was another story, quite worse, in that regard. Evidently working with low level analog signal and keep it clean is much harder than working only digitally.
Even buying a linear, perfectly shielded and 5V calibrated PSU for it didn't solve the problem.

Do the results yielded by Dirac Live depend on the quality of the side measurements and coaxial digital cables?

After reading your description of the measuring stage, I'm inclined to say that the sloppy technique used has surely influenced the results for the worse.
After many, many trials I've found out that for really top results is best to be perfectly R/L symmetrical during the 8 additional points. And obviously better not to be between speakers and mic, hehe.

To limit variables as much as possible, I even exit the room during each measure and work remotely and I've put some faux fur on the mic tripod to avoid reflections

I've also found that Dirac tends to produce a somewhat thin sound if in one or more lateral points pick-up too much bass (typically the lateral high or low point is in a much more modal bass reinforced position than listening position OR if the points are not spread enough (so it somewhat overcorrects in the listening position).
For my taste, my room and equipment, with Dirac my best results are obtained with the program in "chair" mode and with measures done in a square of 100 cm W/L and 50cm H with the listening position in the center.

Surely using bad cables doesn't help, but the measure stage is very important with Dirac.


I'm really waiting for the DG-58 now to do a stress comparison test

I think it should be easier regarding the measures, with less things that can go wrong (only 1 measure point) and I don't have to use the computer for it, that is sure.

[meltemi]

Originally Posted by nvp

Hi Matia, I have actually compared the Minidsp DDRC-22D with the DG-48 in my system a few months ago. The dutch importer has demonstrated the unit in my home. However, I do not quite know what to make of the results.

First, the guy has come with two very dubious RCA digital coaxial cables, i.e. one was 3-4 meters long while the other cable was half a meter (or less) long. I do not think either of the two cables was a dedicated digital cable. (I specifically told the guy to bring two dedicated digital coax cables as I do not have such cable but he did not considered that it is important...)

Second, some of his measurements seemed very sloppy. During one of the (side) measurement his body was blocking the sound coming from one of the speakers, while for a different (side) measurement he litteraly placed the mic behind my coach - again there was no direct path between speakers and mic. (When I have pointed this out to him he said that the side measurements are less important...)

Now regarding the obtained "results", IMO the two correction algorithms did a similar good job. They both have improved significantly the quality of the bass and also the soundstage and stereo image. I have preferred the DG-48 as it sounded a bit fuller. Dirac live produced a thinner sound (i.e. less bass and slightly more details) even when the guy tried to replicate in Dirac the correction curve I use in Accuphase.

I was rather proud (and relieved at the same time) to hear that the DG-48 was slightly better, but I was also happy to hear that my extremely sensitive (and thus revealing UNO) did not picked up any noise whatsoever from the MiniDSP unit (which was connected into the PS-12290 unit).

I hope you can provide some feed-back Matia. Do the results yielded by Dirac Live depend on the quality of the side measurements and coaxial digital cables?

Real ugly ! The importer obviously doesn't have any idea about digital technology nor room correction nor the products he imports, but nevertheless wants to make money with them, brrrr...

SPDIF cables (RCA digital cables) should be 75 Ohms coax, and I'd recommend to keep their length as short as possible, because of SPDIF's relatively low signal level (0.5V).

There should be no obstacles between speakers and mic. Additional side measurements help to sort out single spot vs. general characteristics of the room.
(You can find some basic thoughts about correction under "room correction" in B&W's DB1 white paper downloadable from here: B&W Group North America Service & Support - Reference Materials)

Accuphase DG-48 or DG-58 will do no harm to the typical Accuphase sound, even in bypassed (uncorrected) mode, but my Tact RCS 2.0 did. Should be a good idea to first check for changes in the Sound, when equipment is inserted into the signal path without correction.

[meltemi]

Originally Posted by Mattia

I will also compare the DAC section of the DG-58 to the DC-37 I am also waiting for.

Mattia...please make sure that both will be at the same output level, which in practice is not as easy to achieve as it seems. And sorry for not having answered your PM regarding the Swiss dealer's address; I could not answer, since I'm not a subscriber.

Martin

[Mattia]

Hi Martin,
why you say that the same output level is not easy? Usually when I set levels I use a pink noise and a quite precise, calibrated, sound meter that averages X seconds of sampling.
Is there an hidden trap in that approach?


No problem for the PM, I succeed in finding the way to spend my money anyway

[meltemi]

Originally Posted by Mattia

Hi Martin,
why you say that the same output level is not easy? Usually when I set levels I use a pink noise and a quite precise, calibrated, sound meter that averages X seconds of sampling.
Is there an hidden trap in that approach?

I was thinking about using the DG-58 room correction features and then comparing it's analog outputs with the ones of the external DAC (DC-37) fed by a digital output of the DG-58.

In my configuration (with DC-901) the analog output level of the DG-58 is considerably higher than that of the external DAC.
Attenuating the DG-58 output level by manually adjusting the gain in the DG-58 not only affects the analog outputs but also the digital outputs. The level difference between DG-58 and external DAC cannot be compensated this way.

Comparing the DACs only by feeding them with the same (split) signal from a digital source will work, though without being able to profit from DG-58 room correction features.