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Inter.View with Glenn Zelniker, President of Z-Systems

by Lucio Cadeddu

[Italian version]

LC >
The digital technology has brought so many changes into our small HiFi World. Now it seems it can help to solve one of the audiophiles' worst nightmare: room acoustics.
According to you, how much can be done to improve room acoustics without using any additional HiFi component?
In other words, may you tell us your experience about room tuning before deciding to solve these problems (room anomalies and the like) using digital technologies?

GZ >
One of the biggest problems facing high-end customers is that they might spend a fortune on speakers with a known good, fairly-flat frequency response, but when they get home and place these speakers in their room, the in-room response is dreadful.
There's still no replacement for good positioning and attention to acoustic and architectural details, and a good amount can be done by paying careful attention to these factors.
When you've done all you can do in this regard, it's often necessary to consider doing correction electronically. Until recently, there weren't many good ways to do this.
Analog equalizers have a number of serious problems.
Cables (although they can certainly have audible effects) are not the right way to go, either.
A sonically transparent parametric equalizer like ours is the most controllable, repeatable, dramatic improvement you can make.

LC >
May you tell us how and when have you decided to design a digital preamp-equalizer?
Was it a pro-studio idea turned into a home design or was it the other way around?

GZ >
The rdp-1 is a direct descendant of our professional disc mastering equalizer, the z-q1.
The z-q1 is widely used throughout the professional mastering world, and many of your compact discs were mastered with this piece of equipment.
In the professional audio world, mastering engineers are known to be very critical listeners, and many of the mastering engineers who heard the z-q1 agreed that it was the best digital equalizer they'd ever heard.
At the same time, I was frustrated for many reasons by the fact that my high-end playback had no tone controls and so were a lot of my friends and acquaintances in the high-end audio world.

As we all know, the high-end all but abandoned tone controls for a good reason -- they don't sound good, with very, very few exceptions (the Cello Audio Palette being the only one I can think of at the moment).
When done correctly, however, they put a remarkable amount of power and flexibility in the hands of the user.
I saw in the z-q1, which is our professional product, an opportunity to bring our advanced digital signal processing (DSP) technology to the high-end market.
As it turns out, a high-end dealer in the US (Mark Goldman at Sound Components, formerly with Wilson Audio Specialties) had already seen the z-q1 and had the same idea.
Mark was instrumental in convincing us to add a number of features to the z-q1, overhaul the cosmetics, and release it as a consumer product. This was nearly two years ago.
After nine months of work which actually constituted a complete overhaul, the rdp-1 was born.

LC >
Your RDP-1 is a sophisticated HiFi component and it requires some effort to be exploited at its best.
Do you think it will be possible, in the near future, to design a similar component a little bit simpler and user-friendly?
What about a test CD from Z-systems to help with room fine-tuning?

GZ >
On the one hand, the rdp-1 can be slightly complicated to use when trying to do room correction. This is where the retailer is supposed to step in. We're training our dealers to do room tuning with the rdp-1.
On the other hand, it's quite simple to use the rdp-1 as a tone control once you learn a few basics. Because it's so flexible and programmable, it can be set up to mimic simple bass and treble controls, which are easy to use.
Once the user becomes more familiar with the unit and he/she has learned to correlate changes in settings with tonal changes, it's amazing what can be accomplished.

We do have an equalization product in development which is not quite as *parametric* and is closer in operation to a six- or seven-band graphic equalizer.
That is to say, the center frequencies and bandwidths will be fixed, but the amount of boost or cut at those frequencies will be variable.
Then, all you'll have to do is reach for the correct knob and turn it. This product won't be nearly as powerful or versatile as the rdp-1, but it will be much simpler to use and will still be a great tone control.

In the future, we'll be releasing a test CD with *before and after* examples. Specifically, there will be an unequalized (or poorly equalized) track, followed by a track which has been *repaired* by the rdp-1.
The liner notes will provide the settings used to repair the tracks, as well as an explanation of why those settings were chosen.
We'll have some of our well-known mastering customers helping us make this CD, and we expect it will be very useful for our high-end customers and dealers.

LC >
Die-hard vinyl-addicts don't feel comfortable translating their analog data from their turntables into a sterile sequence of 0's and 1's.
What's your point of view on analogue HiFi reproduction?
Many audiophiles claim vinyl is coming back, how do you see the present situation?

GZ >
I think it's possible to view analog and digital playback as two separate entities.
One could take the point-of-view that our style of equalization is applicable to digital playback and that analog playback is, perhaps, best left untouched.
Before making that decision, however, I believe it's critical to have a listen to all that our technology has to offer.
For example, we make a companion analog-to-digital (A/D) converter called the radc-2. The radc-2 costs only $650 and allows analog signals to be brought into the rdp-1.
At this point, all of the rdp-1's features can be applied to the the analog signal.
Here's where critical, unbiased listening is important: is the signal produced by the radc-2 really sterile, and do the benefits of having the rdp-1 in the playback chain outweigh its sonic drawbacks, if there are indeed *any* sonic drawbacks?
I think that very, very few audiophiles have ever had the experience of running the output of their phono section into a high-quality A/D converter.
What they'll likely find is that a good A/D like our radc-2 does a fine job of preserving the character of the vinyl/tonearm/cartridge/RIAA combination.
It won't sound sterile like they're expecting.

As for my point-of-view on analog reproduction, I'm all in favor of it!
Analog does a number of things very well, and I think analog recording is still a very important part of modern-day CD production.
I've heard many phono set-ups that sounded wonderful and I do hope that vinyl continues to exist as a viable medium if for no other reason that it's pretty good, it makes a bunch of people happy, and that it's an important part of our high-end heritage.
As for my own personal preference, I don't currently own a turntable. I do, however, own a beautiful Ampex ATR102 (for the unfamiliar, this is a 1/2* two-track mastering tape deck and is one of the two or three machines that most vinyl gets cut from at the mastering house).

LC >
How do you see the future of Hi-end home audio reproduction?
Do you believe in a total audio-video integration?
Do you think we're going towards fully-automated room-adaptive HiFi systems?

GZ >
This is a difficult question for me to answer because I find myself in conflict. I like the beauty and simplicity of two-channel playback systems, but the larger consumer market is being driven toward multi-channel systems.
And yet I must admit that multi-channel has its charms.
In the lower end of the market, I think you'll certainly see more audio-video integration and you're already seeing it in the high-end with products such as the Theta Casablanca.
The only problem I see with this is that high-quality music reproduction may suffer as a consequence of having to manufacture six channels' worth of equipment at a price that's still acceptable to the consumer.

So, I certainly believe in total audio-video integration with the proviso that two-channel reproduction shouldn't be sacrificed in any way.
As for fully-automated room-adaptive systems, I don't know.
I actually hold a U.S. patent for an adaptive room correction system, but I'm not completely convinced that they're the right tool for the high-end market, especially in the multi-channel case.
I don't think there's any substitute for a well-trained professional with a good set of ears.
Analytically, it is possible to set up and solve, in real-time using DSP, an optimization problem which corresponds to the room correction problem, and this is what these adaptive systems do.
I just feel that the solution is not always robust and that it's not necessarily the solution to the right problem in the first place.
It's amazing what can be done in DSP nowadays, to be sure, but when music is involved, the front-end still needs to be human.

LC >
The new DVD is ready to invade the market. The audio standard seems reasonable (some say 96/24, others are pushing towards some SuperCD format at 100 kHz...), what's your opinion on the DVD media in general?

GZ >
I'm very, very excited about the potential DVD holds. I, for one, hope to see a real two-channel 24-bit 96 kHz PCM track. It would be nice to see a very high-quality multi-channel format, too, but that's secondary in my mind.
Remember ping-pong stereo? I can't even imagine how most mainstream recordings will utilize six channels.
Anyway, there are a number of reasons why the 24/96 standard is appealing and I think a lot of digital's detractors may have to change their opinions when they hear 24/96 done to its full potential.
I could fill several pages explaining why it's a better standard and what we all stand to gain and why, but I'll leave that for another time if anyone cares to hear what I have to say on the matter.

LC >
What's on your desk now? What about a budget-conscious RDP-1 clone?

GZ >
Guess what? We just started shipping the rdq-1, which is a budget-conscious brother (not a clone) of the rdp-1.
The rdq-1 has all of the equalization functions of the rdp-1, but is designed to be used in a system where there's already an analog preamplifier in the playback chain.
Whereas the rdp-1 has six digital inputs and three digital outputs, the rdq-1 has two of each.
The rdq-1 is missing the rdp-1's digital volume control and remote control, but it still retains the exact same equalizer section, which we call Transparent Tone Control.
The rdq-1 lists for $3,000.

I've already mentioned the $650 radc-2 A/D converter. Later this month, we'll begin shipping the rdq-6 and the rdac-6, which are a six-channel EQ and a six-channel digital-to-analog converter, respectively.

Dr. Glenn Zelniker
President and Chief Designer Z-Systems Audio Laboratories.

Courtesy Glenn Zelniker for TNT-audio.
Copyright © Lucio Cadeddu

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