Accuphase DG-68 Digital Voicing Equalizer Associated Equipment

Sidebar 2: Associated Equipment

Digital sources: dCS Rossini SACD/CD transport, Rossini DAC, and Rossini Clock; EMM Labs DV2 Integrated DAC; Synology 5-bay NAS 1019+; Roon Nucleus+ music server with HDPlex 200 linear power supply; Uptone Audio etherRegen, Small Green Computer Sonore opticalModule, TP-Link gigabit Ethernet media converters plus multimode duplex fiberoptic cable (2), Linksys routers (2); Small Green Computer linear power supply & Small Green Computer/ HDPlex four-component, 200W linear power supply (3); external hard drives, SSD USB sticks, iPad Pro; Apple 2017 Macbook Pro computer with 2.8 GHz Intel i7, SSD, 16GB RAM. Preamplifier: Dan D'Agostino Momentum HD.
Power amplifiers: Dan D'Agostino Progression monoblocks.
Loudspeakers: Wilson Audio Specialties Alexia 2.
Cables: Digital: Nordost Odin 1 & Odin 2 & Valhalla 2 (USB) & Frey 2 (USB adapter), Wireworld Platinum Starlight Cat8 (Ethernet), and OM1 62.5/125 multimode duplex fiberoptic cables. Interconnect: Nordost Odin 2. Speaker: Nordost Odin 2. AC: Nordost Odin 2; AudioQuest Dragon, Dragon HC and Thunderbird.
Accessories: Grand Prix Monza 8-shelf double rack & amp stands, 1.5" Formula platform, Apex footers; Nordost QB8, QX4 (2), QK1, and QV2 AC power accessories, QKore 1, 3, and 6 with QKore Wires, Titanium and Bronze Sort Kones, Sort Lifts; AudioQuest Niagara 5000 power conditioner & NRG Edison outlets & JitterBugs; Tweek Geek Dark Matter Stealth power conditioner with High Fidelity and Furutech options; GreenWave AC filter; Ansuz Darkz T2S resonance support feet; Wilson Audio Pedestals; IsoAcoustics Orea footers; Stillpoints Aperture panels; Resolution Acoustics room treatment; Stein Music Super Naturals, Blue Suns/Diamonds, Quantum Organizer; Bybee Room Neutralizers; Absolare Stabilians; Symposium Ultra Platform; Marigo Aida CD mat.
Room: 20' L × 16' W × 9' H.—Jason Victor Serinus

Accuphase Laboratory Inc.
US distributor: Axiss Distribution Inc.
17800 South Main St., Ste 109
Gardena CA, 90248
(310) 329-0187

Anton's picture

I would think your room has to be OK for it to be able to produce a decent room curve to begin with.

Your idea of continuing to tweak your room while you have the toy is genius.

It would be cool to have a "mother module" to use to set the room, and then a much less expensive "servant module" or chip that could talk to your DAC that you could then plug in to keep 1-3 curves while allowing the mother ship to continue her sonic journey.

Archimago's picture

Nice to see audiophilia using (at least not afraid of) EQ and finding benefit in "room correction" techniques.

So, basically, from a technical perspective is this performing 2-channel 35-band parametric EQ (settings up to 50kHz)?

Is there any time-domain correction being done when fed with room information (doesn't look like it?)?

teched58's picture

$24,000 seems a̶ ̶l̶o̶t̶ ̶o̶f̶ ̶m̶o̶n̶e̶y̶ very affordable for a 35-band parametric equalizer!

Anton's picture

Wow, what a great addition that would be.

RichT's picture

Something very unexpected here - the flat response curve is incredibly flat, I would estimate -3dB +1dB. This is a flatter response than most professional studios achieve, even the best. It’s totally flat 30Hz to 90Hz, which is absolutely remarkable. This Is very special room.

Kal Rubinson's picture

And not everyone wants flat. ;-)

MatthewT's picture

Perfect is boring.

Kal Rubinson's picture

And, under some conditions, undesirable.

MatthewT's picture

Is the sum of its flaws, and I love them all.

latinaudio's picture

are a necessity. What is certain is that the sound perceiver must be taken into account: the brain. And since no two human beings are alike, it will ALWAYS be necessary to adjust the bass, treble, midrange to each person... in order to have a pleasant experience. Tone controls ARE an unavoidable necessity, and hifi manufacturers builders would be arrogants if they don't accept it. So remember: it´s not only the room, are the persons, specially the owner of the equipment :)

Ortofan's picture

... published in the November 1973 issue of Audio magazine.

It includes a description of the then new Altec 729 Acousta-Voicette one-third octave equalizer and the Altec/HP 8050 real-time analyzer.

Presented is a rationale as to why the corrected frequency response should not be flat over the entire audible range.
The proposed optimum frequency response is flat up to 2kHz, followed by a roll-off above than point at the rate of 3dB/octave.

Kal Rubinson's picture

Good stuff at the time but acoustical science and audio componentry have moved on.........................

Ortofan's picture

... the latest developments in acoustical science (and audio componentry) suggest is ideal?

Kal Rubinson's picture

Toole's book is a good place to start.

Ortofan's picture

... those under the Harman umbrella, agree with Dr. Toole's findings and implement them in their products?

Kal Rubinson's picture

I suspect that all the current AVRs and prepros incorporate them in their EQ options.

zuman's picture

I've been listening seriously and buying good gear for over 40 years, and I firmly believe that the effects of some "tweaks" CAN be measured while we haven't yet discovered how to measure other audible tweak results. However, I also believe that many tweaks are placebos. Is the DG-68 sufficiently sensitive to identify/quantify/adapt to some of the supposed "night-and-day" effects of some of these tweaks?

Anton's picture

Of course, no matter the outcome no minds would be changed.

We are audiophiles, after all. ;-D

pbarach's picture

I wonder how this unit's results would compare to some of the other (much less expensive) room correction systems, e.g., Audyssey, ARC, Trinnov.

Kal Rubinson's picture

Hard to compare correction systems which reside in different hardware.

georgehifi's picture

Love to have this thing, but I would have liked to have heard the comparison of what Rossini Ring/Dac was like from the Accuphase's digital outputs compared to it's own ESS dac (never been a lover of the ESS converters). (was it done???)

Cheers George

AudioBang's picture

Back in the late 90s I bought a Sigtech for $7,300 which, in addition to room EQ, performed time alignment, cancellation of late arriving ceiling, floor and wall reflections out to 50mS, and had the ability to compensate for spectral build up [from room corners, etc].
I owned a pair of Dunlavy Vs at the time, later upgrading to the SC VI.
Since the Dunlavy's are all time-aligned to begin with, as expected, the impulse response did not visually change after a correction filter was applied. I too found it easy to get caught up in jumping from correction filter to correction filter and being distracted from the music. The Dunlavy recommended listening position was against the long wall so the speakers could be placed with a wide listening angle - up to 120 degrees! [per the manual] and obtain the smoothest bass response by eliminating room nulls. I liked mine at about 100 degrees as there was a level of psychoacoustic wonder at hearing a phantom center image with the speakers 12 feet apart while still presenting a reasonably proportioned soundstage. I later learned from the SigTech measurements, that with the listening position against the rear wall, the room buildup in the bass was enormous! A significant contribution in my system that the Sigtech made I felt, was ameliorating the room build up against the rear wall as well as smoothing a 12dB delta from 30hz to 90hz - I suspect from the interactions between the bass drivers positioned at the floor and the top of the cabinet. The low frequency measurements of my speakers from Dunlavy's very large anechoic chamber showed a similar 12dB peak to null although at slightly different frequencies from my room. Also, I recall, not all of that 12dB difference could be flattened as you wouldn't want to add unprecedented gain at high listening levels at the null which could blow the drivers. In a nutshell, in my room, taming the bass [overhang] was a significant factor in arriving at more transparency and I felt that manually treating the room [absorption in my case] for first sidewall reflections worked better than relying on the Sigtech's ability to cancel them out - even though these reflections were eliminated on the filtered impulse response. The measurement capability of these reflections was instrumental in confirming the before and after effects of midrange smearing that was eliminated after applying absorption from first reflections. I was not successful attempting to fix bass problems with corner traps.
The 2khz -3dB/octave rolloff was the recommended default filter. The flat filter sounded dry and sterile and was not pleasurable to listen to although I look back and wonder if part of the reason was that the recommended rolloff starting at 2khz may have masked the sub-par 90s digital in my system [Wadia 270 Transport/27ix DAC]. For what it's worth...

John Atkinson's picture
AudioBang wrote:
Back in the late 90s I bought a Sigtech for $7,300 which, in addition to room EQ, performed time alignment, cancellation of late arriving ceiling, floor and wall reflections out to 50mS, and the ability to compensate for spectral build up [from room corners, etc].

Stereophile's December 1996 review of the SigTech system will be posted to the website the week starting August 9.

John Atkinson
Technical Editor, Stereophile

tonykaz's picture

I recall setting up our Listening Rooms at Esoteric Audio in the 1980s.

We ended up with a Semi-Anechoic type result that needed the Largest Mono Amps pushing thick MH-750 Music Hose Speaker Cabling.

Do our brains re-calibrate room accoustics for us ( to some extent ) ?

I suspect that Room Problems are exasperated by Loudspeakers with too-powerful Bass circuits and no balancing electronic circuits..

B&O make that gigantic Beolab 90 that features built-in Room Correction.

Full Range Loudspeaker Manufacturers should include some sort of Bass management system as an included component. ( Genelec )

Leaving Accoustic Engineering in the hands of purchasing Consumers seems irresponsible.

Accuphase Gear is Georgous

Tony in Venice Florida

AudioBang's picture

I concur that our brains recalibrate room acoustics for us - to some extent....
Interestingly, per MF and other Stereophile reviews on the ISO Acoustics speaker isolators, I tried three sets on my Dunlavy SC VIs [650 lbs each] and they completely altered the bass. On the one hand, I agree with one of the reviewer's comments that they were "different" and on the other, the bass overhang that I am used to [assuming] from room modes, was reduced an order of magnitude as if "where did it all go?" But the transparency, depth and expanded soundstaging these footers offered was unexpected and unprecedented. I'd take these results 10X over any EQ solution. Because the rebuilt 4-way crossovers reside outside the speaker, while I was contemplating trialing the footers, I had disconnected the bass completely out of the picture to test whether the vibrational bass coupling to the floor made any difference to the midrange/treble. I didn't hear any difference. But after installing the footers everything transformed at the magnitude that MF stated in his review. I can only assume that even with just midrange and tweeter operating, something vibrationally is happening to/within the 650lb cabinet causing blurring to occur. My brain can not connect how that happens. BTW Stereophile, thanks for your value-add here. This was one of the most profound improvements I've experienced.

tonykaz's picture

Can we hear from the Loudspeaker Manufacturer on these devices.? Why don't they include these with every speaker?

I probably consider them to be like Engine Mounts for a vibratingly harsh Car, Truck, Boat Engines.

NoiseVibrationHarshness is a science, we should be able to explain these phenomenons and bring about consistant effects/affects.

In the 1980s I sold large quantities of Audio related do-dads, Audiophiles love to tinker around with this stuff.

Tony in Venice Florida

Kal Rubinson's picture

Can we hear from the Loudspeaker Manufacturer on these devices.? Why don't they include these with every speaker?

Good questions and there are a couple of speakers with them on their way to market The general answer is that it will increase the price of the speaker and manufacturers have to compete on price in the real world.

It evokes the memory of an amp manufacturer who told me that I could not realize the full potential of his product without a particular after-market power cord. I was surprised at that and asked why he would not just include it. He replied that it was a matter of price. I bought one anyway (who would not want his new amp to sound its best) but I found it was absolutely not audibly different from the stock cord. He should not have opened his mouth.

Ortofan's picture

... is including shock-mount feet.
Speaker prices range from $1,850 to $4,250 each.

Kal Rubinson's picture

PSB, too.

tonykaz's picture

Good Better Best has been a Sales Standard in all sorts of Product types..

I'd expect better from the Full Range Transducer System manufacturers, just as we've come to expect ( and rely on ) Stereophile Reviewing and Editorial Standards.


Audiophiles are typically DIY kinds of folks.

I'm a Fan of Meridian type of Music Systems approach from Manufacturers. I can enjoy a high performance designed full System from one Company.

Still Tweaking one's music systems can be a nice little distraction from the World problems crushing our shoulders.

Big Fat Stiff Power Cords are visually impressive, you could say "those power cords alone cost Thou$$$$$$and$$$ of Dollars!! ( even toss a handful of hundred dollar bills on the floor behind the speakers ( to show off even more )

Audio stuff can still be fun! I think

Tony in Venice Florida

tonykaz's picture

I just heard that the NY Auto Show is cancelled.!!!

We're not out of this China Plague yet

Tony in Venice Florida where masks are still optional

Kal Rubinson's picture

But what about the NY Audio Show?

tonykaz's picture

It seems that we are entering a new phase of China Pandemic hysteria with this Fresh Strain that can be understood but isn't..

So, we might usefully predict that Big Shows will set the pace for all the little Shows like Audio and/or things like Tool Shows.

CDC is predicting the New Strain will take the rest of this year to run it's course ( in USA that has less than 100% Vaccinations depth ).

Global Vaccination percentages have barely scratched the surface so we are a looooooonnnnnnnngggggg way from Herd Immunity!

Will it predictably take the Standard 3 to 4 years for this blight to run it's course ???

Will the politicians and media continue to foster Health condition Panic among the innocent polis ?

I have the feeling that Streaming and DACs like the dcs Bartok will have overwhelmed HighEnd Audio by the time this Virus is tamed.

It's time to sell off my Koetsu & Vinyl collections

Tony in Venice Florida

AudioBang's picture

I think you would be a very cool neighbor to have Tony :)
I enjoy your industry stories and commentaries from your experiences.