REVIEW: Topping D90SE DAC - Part III: Subjective Impressions, AMPT, and Summary. A few words about "warmth" and "accuracy" in sound systems.

This is the final part of my trilogy review/evaluation of the Topping D90SE DAC (see Part I, and Part II for the objective testing results).

As we end off, let's close with a discussion of subjective impressions developed over many evenings of listening (about a month or so). I've described the soundroom previously in some detail and for the two channel system, the main amplifier is my home-assembled Hypex nCore NC252MP, main front speakers are the Paradigm Reference Signature S8 v3, and dual subs (main Paradigm SUB1 with the little Polk PSW111). The Topping D90SE feeds my Emotiva XSP-1 preamp. All cabling is balanced XLR from DAC to amplifier (no need to fret, inexpensive Monoprice Stage Right XLR runs are all ya need, feel free to spend more on cables if you see fit of course).

I listened both with and without DSP room correction activated; generally I prefer with DSP. Knowing the frequency response characteristics (flat to 20kHz) and setting to "Fast Roll-off Linear" (Filter 5) allows me to use the same DSP settings for my room interchangeably with the RME ADI-2 Pro FS Black Edition without need to remeasure (equivalent frequency and time-domain performance). As discussed before, one of the benefits of a high quality DAC is that we can have even more headrooom with DSP processing whether it be full room correction or applying volume normalization like ReplayGain.

MEASUREMENTS: USB Isolation with Nobsound ADuM4160 device and hi-res DAC. The world these days, and the audiophile microcosm.

 

After writing about very high resolution measurements with the E1DA Cosmos ADC last week and touching on basically "state of the art" fidelity like the Topping D90SE, for this week's post, I thought it would be good to talk about something more "fundamental". Often spoken of among audiophile tweakers but rarely have I seen evidence of actual value/effect for many of these devices.

Before I begin with this post or even show you anything, let me just say that I do not believe audiophiles need USB isolation for use with devices like DACs unless you know you have noise issues. I think we've all see indiscriminate suggestions that audiophiles need all kinds of noise filters and isolators (like this, or this). Sometimes these things cost quite a significant chunk of change compared to the downstream device (like DAC) itself!

Over the years, I have tried out a number of USB DACs with computers and simple streamer devices like the Raspberry Pi. With a normal set-up, I cannot say I have ever heard an issue with any of the various decent DACs I've tried. Likewise, measurements already suggest that in general there are no major noise issues with at least reasonable modern devices.

However, there are times when the system is complex enough where indeed you do see ground loops and noise like the 8kHz USB PHY noise pop through. A couple months back, I showed you some of this when we took the rather useless AudioQuest JitterBug FMJ for a spin in some of these situations! Today, let's look at the effect of that little inexpensive Nobsound ADuM4160 USB Isolator (typically can be purchased for <US$25) you see in the picture above.

PREVIEW: Oppo Sonica DAC (Thanks Oppo for making it right... On the rationale for technical perfection.)

Usually, I don't post many "preview" type articles, preferring to give you guys "the goods" when I've had an adequate amount of time with a device (usually at least a month or so) including measurements and such. I'll discuss why I'm posting this earlier as we go along...

Well, this is what showed up at my door last week:

That's of course the recently released Oppo Sonica DAC. A "hi-fi" USB, S/PDIF, ethernet, WiFi, Bluetooth digital player with DLNA streaming capability, part of the Oppo Sonica "family" of audio devices. The only other device with this moniker currently being the Sonica Wi-Fi Speaker, capable of 24/192 streaming. Coming later this year apparently is the larger Sonica Grand.

Let's have a peek inside the box...

Updated Room MEASUREMENTS & MUSINGS on Importance of Sonic "Accuracy" and the Audiophile.

Chapter I: Another Round of Room Measurements...

Recently, I acquired some more LP's, got a few more IKEA Kallax storage units for said LP's and put up some art as well. Here are front and rear shots of the sound room the other day...

With the physical changes and reviewing my post from last year regarding the use of (((acourate))) along with suggestions made by Dr. Uli Brueggemann and Mitch Barnett (aka Mitchco), I decided that it was time to re-do the room measurements and see if I can incorporate the important suggestions - 48kHz sampling rate for the measurements, sweep range of 10-24kHz, and incorporation of the subsonic filtering at 15Hz. If you're wondering, the dimensions of the room are ~20' x 15' x 8' with a slight frontal tapering as shown; not a huge room by any means and not ideal dimensions but at least it's not squarish/cubish (here's a study on room dimensions and acoustics). It's in the basement of my house, built as a family media room with extra thick walls to reduce sound leakage when the kids are asleep at night (I pretty well can run the sub at reference levels with kids asleep upstairs at night so long as I close the door to the basement). The main speakers - Paradigm Signature S8v3's - are 7.5' apart up front, and the sweet spot is approximately 9' from the speakers arranged like an isosceles triangle. I make sure there is decent amount of space between the couch and the rear LP storage (>3'). [As you can see, I have the ~15-year old rear full-range Paradigm Studio 80v3's back there.]