Q&A with Steve Nugent of Empirical Audio

Steve Nugent is the founder of Empirical Audio and if you frequent Audio Asylum or AudioCircle, you'll have undoubtedly seen his posts as audioengr. Empirical Audio makes a number of products including the Overdrive® SE USB DAC/Pre, Synchro-Mesh Reclocker, Off-Ramp USB Converter, and the Short Block USB Filter. As you can surmise from this list, external clocking speaks to a certain design approach and focus on among things the elimination of jitter. We talk about this approach and lots more in this Q&A and I'd like to thank Steve Nugent for his time and for participating in this Q&A. Enjoy!

What got you started in Computer Audio?
In the early years of Empirical Audio I modified other manufacturers gear for customers, mostly DACs and transports. During this period TI developed the first USB interface chips for audio and the M-Audio Transit, which utilized these became available. The Transit was one of the first inexpensive USB digital audio interfaces. There were several customers that asked me to do mods to the Transit to improve the sound quality, so I improved the clock and the power delivery etc. I like the results so much that I offered my own hot-rodded Transit called the Off-Ramp that used the Transit board.

"...I realized that this was the perfect melding of my 25-year digital design background in the computer industry (Intel and Sperry Unisys) with my passion for music and stereo playback."

After doing this, I realized that this was the perfect melding of my 25-year digital design background in the computer industry (Intel and Sperry Unisys) with my passion for music and stereo playback.

After much prodding from my customers, I finally stopped modding things in 2009 and launched my own product designs. I knew there would always be limitations in other manufacturers designs that mods would not rectify. I could finally have full control of the hardware designs, enabling me to optimize everything.

What do you think sets you apart from other designers?
Several things set me apart. My extensive experience in the computer industry as a digital designer gives me a leg-up on most high-end audio companies. I have designed everything from massively parallel supercomputers to portions of the Pentium 2. In addition to the digital design experience, I was fortunate in my computer career to learn about many of the more esoteric areas of design, such as grounding, shielding, EMI, ESD, power delivery and transmission-lines. I apply all of this knowledge in every design.

Modding other manufacturers products for almost 10 years was extremely beneficial. I learned what not to do, as well as how to do it right. I was frankly disappointed to see so many design mistakes repeated over and over. Modding also allowed me to identify quality parts like op-amps, capacitors, resistors and inductors that can make a substantial difference in performance. Most designers don’t have time to experiment with these to determine the best ones and how to use them effectively.

My experience designing digital and analog cables in the early years of Empirical Audio is also helpful. I used to have a full-line of cables with several patents issued on the technology. It is striking how much of my cable technology actually goes into my component products. Most audiophiles focus on cabling outside of their components, but the cabling inside is every bit as important.

"Most audiophiles focus on cabling outside of their components, but the cabling inside is every bit as important."

Another thing that sets me apart is my design philosophy. I learned by modding so many devices that more is not less. More is bad. What I mean is that signal paths, both digital and analog should be minimized as much as possible. It is tempting in a DAC for instance to use an active stage, whether Op-Amp, tube or discrete, for each function including I/V conversion, filtering, gain, volume and output drive. Separating these functions makes the designing easier, but ultimately adds distortion, noise and most of all compression. If you want to suck the life out of the music, compression is the way to do it.

I am also one of the engineers that you hear about that must be taken out back behind the shed and shot in order to actually ship the product. I never really stop engineering and optimizing it. It's a blessing and a curse. But since my company is small and nimble, it allows me to take advantage of the latest technology and technical breakthroughs, offering the best performance to my customers.

After so many years on this planet I have also learned another important lesson, and that is to leave the ego outside and leverage the best minds on the planet whenever possible. Most designers are reluctant to incorporate other third-party designs into their own, but I freely admit that I am not an expert in every single area of the design. I would rather leverage others that are experts in these areas. That way, I can combine my strengths with theirs to make a fully optimized product.

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COMMENTS
Steven Plaskin's picture

Thanks for the interesting interview Steve. 

As a side note:

I tested 2 different DACs made by the same manufacturer last week both with the same USB interface. The $4K DAC did not come close to the sound quaility of the $9K DAC.

Would using an Off-Ramp change the results? I honestly don't think so. But I do have a great deal of respect for you and your products. You have done a great deal to advance computer audio.

Best regards.

Steve

labjr's picture

"The final leg of this stool is the loudspeaker crossover, which should be eliminated. This is only possible IMO with digital technology. "

Sigfried Linkwitz thinks otherwise. Sends the signal through many opamps and passive components. Supposedly the speakers sound good. I don't see why he can't do this with DSP and make it sound even better. Digital is the future.

Empirical's picture

"Sigfried Linkwitz thinks otherwise. Sends the signal through many opamps and passive components. Supposedly the speakers sound good. I don't see why he can't do this with DSP and make it sound even better. Digital is the future."

Linkwitz filters are very good because of the low phase-shift.  The problem is that all hardware filters are flawed because the components; caps, resistors and inductors are flawed.  None of these are text-book perfect, so the behavior is not ideal.  Also, op-amps are anything but perfect.  They are taught as perfect gain-blocks to the engineers, but they also have their share of flaws as well. 

Any kind of active stage, whether op-amp, discrete transistor or tube has the disadvantage of adding noise, distortion and compression.  The more the stages, the more of all of these.  Filters and crossovers usually have several stages.  Even with really low distortion and noise stages, the compression thing adds-up.

This is why DSP is the ultimate answer.  DSP can have zero phase shift.  Not all DSP codes are perfect either.  I have used a DSP crossover in a show system that was good, but anything but transparent.  Even at flat response, it added compression and noise.

On the other hand I have had really good experiences with Amarra EQ, so I know that it is possible to have ultra-transparent crossover DSP code.  The Amarra EQ is like adding nothing at all.  Sweet!!!

Steve N.

Empirical's picture

"I tested 2 different DACs made by the same manufacturer last week both with the same USB interface. The $4K DAC did not come close to the sound quaility of the $9K DAC.

Would using an Off-Ramp change the results?"

 

The power regulation to these interfaces makes all the difference, as well as what happens to the signals after they leave the USB interface.  I've seen lots of things that are unoptimal, such as driving a D/A chip with 3.3V signaling on I2S when the D/A chip is a 5V chip...

If you had an Off-Ramp 5 with S/PDIF Hynes Reg driving these DACs with a good 1.5m S/PDIF cable I think it could best either interface.  The two DACs would likely both sound a lot better and more like each other.

Steven Stones series of reviews in TAS using the Off-Ramp 4 and 5 clearly demonstrate that even a $1500 DAC can sound almost identical to a $8K DAC when driven from a low-jitter digital source.

 

Steve N.

Rob McCance's picture

I can add a little personal experience to this as well.

I use the Audiophilleo USB2SPDIF device. 

I've had all these DACs in the room at the same time and A/B'd them all ad-nauseum:

--NAD M51 
--Metrum Octave (NOS)
--Musical Fidelity VDAC II
--HRT Music Streamer PRO

I play 99.9% 44.1k (Redbook CDs) Non-Upsampled files from a MAC running Pure Music / iTunes. I use wave file format to rip. (storage is cheap)

Withouth the Audiophilleo, these DACs sound worlds apart. Each has it's own distinct signature.

With the Audiophilleo, they all sound orders of magnitude better and even the lowly VDAC and HRT sound pretty darn good. Telling the differences in blind listening tests would be a challenge.

One exception, the one I kept, was the Metrum Octave NOS DAC. With the Audiophilleo in line with that one, it is clearly superior to the others in every way. So it's been my DAC for nearly a year now. 

It's sub $1k and I find it hard to believe that a $10k DAC fed with the Audiophilleo would sound 10x better, or even 2x better.

In short, I completely agree with Steve, based on my own tests.

Rob in Atlanta area

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