Accuphase DG58 Necessity or Novelty

[Mattia]

Speaking about analog,
how do you set the sampling frequency of the Analog In of the DG-58?

I wonder why Accuphase gives the 3 choices (44.1, 88.2 and 176.4 KHz) and the pro and contra of the 3.

I expected to have only one AD sampling frequency, that gave the best digital signal to the DSP to work on without having to reconvert it.

[meltemi]

Originally Posted by Mattia

Speaking about analog,
how do you set the sampling frequency of the Analog In of the DG-58?

I wonder why Accuphase gives the 3 choices (44.1, 88.2 and 176.4 KHz) and the pro and contra of the 3.

I expected to have only one AD sampling frequency, that gave the best digital signal to the DSP to work on without having to reconvert it.

All sampling frequencies are multiples of 44.1kHz.
The higher the sampling frequency, the better the impulse response. Use the highest you can.

Martin

[Mattia]

Tnx Martin!

But why Accuphase put the choice there if 176.4 kHz is the best choice?

Why not simply default the machine to sample the analog-in at 176.4 kHz?

[Mattia]

Still experimenting with my DG-58.

From what I understood looking and comparing voicing results, the "Smooth" voicing uses the lowest "Compensation level" while the "Flat" voicing uses the maximum Compensation Level (I am referring to the settings menu in manual voicing procedure).

In my case, neither of the two is optimal.

The "smooth" leaves to much of my big 40 Hz modal peak, the "flat" is good dealing with the modal but tries to raise to much the valley that I have towards the mid-end of the woofers range (crossover with mid is 380 Hz in the 801 S3) and then if I don't lower that range with the equalizer gives me some distorsion, I still am inclined to think because the woofers often have to work to much out of their comfort zone (I now use auto Gain so the distorsion in that zone is surely not caused by saturation of the input).

The "Mid" level of compensation, found in the "Setting" voicing menu, is the one that gives me the best compromise and the best sound. The 40 Hz peak is sufficiently smoothed and the valley is raised but not too much, so I don't have the distorsion problem, that by the way is easily noticeable because it corresponds often to lower male voices frequency.

Then I can enjoy a good sound even without using the equalizer, or with much less tweaking.

In the end, the DG-58 confirms to be a wonderful machine and a joy to use and experiment with


(now if only RPG will finally send me the 40Hz Modex panels I ordered... ).

[meltemi]

Mattia...The automatic compensation gives usable results, but there is still considerable room for optimization. And, for this, you should take your time.

You might also start to get close to the sonic limits of your Matrix 801 S3.
(I did reach such a point years ago, when I had optimized room correction with my then Tact RCS 2.0.)

BTW, I used Matrix 801 S2 from 1989 - 1993 and Matrix 801 S3 from 1993 - 2011.
The jump to 800 Diamonds was huge, but also required a complete rethinking of the electronics chain, to get the best out of it.

Martin

[Mattia]

Originally Posted by meltemi

Mattia...The automatic compensation gives usable results, but there is still considerable room for optimization.

Absolutely, and for that I really like the user friendliness of the DG-58. It is a pleasure to use, much much better than having to connect and use a computer every time I wanted to tweak and experiment

Regarding the 801 S3, I too think that with the room almost perfectly treated (save for the 40 Hz peak, but in next weeks I'll solve also that problem), with good electronics, maybe I've reached the plateau of what they can offer. Let's also not forget that they are 20 years old, so maybe they are not anymore perfectly in spec.

I was thinking to upgrade them with 800 or 802 Diamonds, but I am incapable of choosing because of one simple fact: the room.
The electronics could always be upgraded in the future to extract the best that the 800 could offer, but my audio room is only 3.6x4.6 meters. As I said it is well acoustically treated and dedicated to audio, but the size is that.

Do you think that the 800 will anyway be better than the 802 in a room this size at the same pressure level?
Sadly here in Ticino the only hi-fi store doesn't provide a try in my room, so really I cannot judge.

[meltemi]

Originally Posted by Mattia

Regarding the 801 S3, I too think that with the room almost perfectly treated (save for the 40 Hz peak, but in next weeks I'll solve also that problem), with good electronics, maybe I've reached the plateau of what they can offer. Let's also not forget that they are 20 years old, so maybe they are not anymore perfectly in spec.

Just carefully tighten the bass chassis screws and occasionally use a demagnetizing sweep for the low frequencies.
I think they are still perfectly in spec, but since 1991, when they were launched, the B&W team did a lot of development (original Nautilus, Nautilus 800 series, 800D and 800 Diamond).

Originally Posted by Mattia

...but my audio room is only 3.6x4.6 meters...Do you think that the 800 will anyway be better than the 802 in a room this size at the same pressure level?

I run my 800 Diamond in 4.14x5.0 meters room, only slightly lager than yours. Since the 800 Diamond are higher than the Matrix 801 S3, you'll probably have to use the spikes, and tilt the speakers forward, so that your listening position is within the 10 degree vertical arc.
You also might need to carefully turn them inward (up to about 15 degrees), so that direct lines from the speakers cross behind your head but before the back wall (not the front wall of course).

Martin

[Mattia]

Martin,
you described almost perfectly my current situation: 801 turned inward and about a month ago I tightened all the woofer and midrange screws that effectively were in need. Glad to ear I did not wrong

I am waiting for the 40Hz RPG Modex panels, curious to see how the woofers would react when I'll lower the room response in that frequency.

I'm also waiting for the Diamond series successor, that if B&W keeps the recent progression rate and series introductions, should be announced in the near future. Then I'll decide.

[Mattia]

A quick question for those who have knowledge of Accuphase products non-public specs.

Does the DG-58 apply a specific calibration curve for the AM-48 microphone?

Because I think it is somewhat improbable that such a "cheapish" microphone would otherwise have a perfect 20 Hz - 20 KHz frequency response as shown here in page 2:
http://www.accuphase.com/cat/dg-58_e.pdf

Problem is that if the DG-58 is expecting an AM-48 in the mic input, and applying specific calibration curve for this mic model, that would preclude me the use of a better mic.

Someone knows the facts?



P.S. Finally I have decided for a preamplifier (mainly for the convenience of a proper, fine grained, volume control). This turn I opted for a C-2420 that I bought as a "transition" pre waiting for the new generation of Accuphase pre's. Still waiting for it.
And now the DG-58 is connected to an old DP-75, that for the PCM 16/44 music I listen to has a simply a SUBLIME DAC section (16x PCM-1702) as far as I am concerned and I prefer it to DP-510 and to DG-58 for CD and 16/44 material Digital to Analog conversion.

[meltemi]

Originally Posted by Mattia

A quick question for those who have knowledge of Accuphase products non-public specs.

Does the DG-58 apply a specific calibration curve for the AM-48 microphone?

Because I think it is somewhat improbable that such a "cheapish" microphone would otherwise have a perfect 20 Hz - 20 KHz frequency response as shown here in page 2:
http://www.accuphase.com/cat/dg-58_e.pdf

Problem is that if the DG-58 is expecting an AM-48 in the mic input, and applying specific calibration curve for this mic model, that would preclude me the use of a better mic.

Someone knows the facts?

Accuphase give the frequency response but no other data.
If you manage to rigorously select mics, you might get close to the published frequency response.

Using a 'better' microphone would also require to know about how Accuphase powers the mic and what the mic's sensitivity is.
All I can say so far is, the mic is not phantom powered (not 48VDC) and the input does not seem to be balanced (verified with a NTI-Audio MR-PRO; NTi Audio Analyzer, Sound Level Meter).

One way of verifying your settings would be to use the free REW (Room EQ Wizard) software together with an inexpensive SPL meter or an inexpensive measurement mic (calibrated by this software; REW - Room EQ Wizard Room Acoustics Software).

Martin