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KUVO Builds All-Digital Jazz Oasis

Public radio listeners in Denver get something most of us don’t: a lot of live jazz music on the radio, thanks to KUVO(FM).

(click thumbnail)Public radio listeners in Denver get something most of us don’t: a lot of live jazz music on the radio, thanks to KUVO(FM).

Mike Pappas, chief engineer at the Denver station, said KUVO is one of very few stations in the country airing live jazz performances.

The station, which calls itself “The Oasis in the City,” prides itself on the live music it offers under the banner “Performance Studio” – as many as 11 performances in as many days during a recent pledge drive. Even during a nonfundraising period, KUVO’s 26-by-38-foot performance space under a 17-foot ceiling plays host to three live concerts each month.

The format includes jazz, R&B, blues, Latin jazz and specialty programming.
KUVO Equipment InventoryAir/Production Studios

Each studio contains the following components:

Logitek Numix console and digital routing system

(3) Neumann KMS-105 mics

(6) Symetrix 528e mic processors

(3) Denon DN-C680 CD players

(2) Sony MD player/recorders

Otari DTR-8 DAT machine (production)

Panasonic SV-3700 DAT machine (air)

Tascam 122 MKII cassette deck

Technics SL-1200 MKII turntable with Ortofon cartridge

(4) Benchmark Media System headphone amps

Telos Systems Telos One phone hybrid

(2) Genelec 1029A speakers with subwoofer

Mogami eight-pair digital cable and 105-strand mic cable

Live Performance Studio and Control Room

(2) Sennheiser MKH800s, sequential serial number, matched pair

(2) Neumann TLM-103 black monoliths

Neumann U-87

(4) Neumann KMS-105

(2) Neumann KM-184

Neumann KM-100 (Fritz the dummy head)

(2) each Sennheiser MKH-20, 40, 60 and 70

Z-Systems 16×16 Digital Detangler

Benchmark Media Systems A-D converter

Lexicon PCM-80 digital reverb

RTS Systems intercom and IFB system

DAS Model 6 Nearfield Monitors

Baldwin 6’2″conservatory grand piano

Mackie 24×8 8-Bus mixing board

Telos Zephyr ISDN codec

32 channel Alesis ADAT multitrack recorder

Sony Direct Stream Digital recorder with Meitner A-D and D-A converters

Grace Design 801R remote controlled 8-channel mic preamp

RF Chain

Harris CD-Link digital STL

Omnia FM Veris processor

Nautel NE-50 exciter

Nautel FM-10 transmitter

Shively 6810BR eight-bay antenna

Bird wattmeter with 3-inch line section

Myat 3-inch hard line

Sage Endec EAS

Sine Systems remote monitoring and control system

Beta Bright Displays
Weakest link

When Pappas arrived at KUVO six years ago, the station’s equipment didn’t live up to the quality of the music, especially in the air studio and production room.

“We were running on 12-year-old analog boards that were literally falling apart. Howe, the manufacturer of the consoles, had gone out of business, so the boards were basically unsupportable,” Pappas said.

Things weren’t much better up on Lookout Mountain, where KUVO’s transmitter site is shared with public radio KCFR(FM) and public TV’s KRMA. KUVO was using a Wilkinson transmitter that was causing Pappas plenty of trouble.

“On average, it would go off the air about three times a week,” he said, occasionally forcing a trip up the mountain to coax the transmitter back on– “usually at 2 a.m. or during snowstorms,” he said.

Pappas, who has been in the audio industry for more than 25 years and has worked on live TV events including the Democratic National Convention, the 1999 Super Bowl and numerous sporting events, knew it was time for a facility rebuild.

Further, he wanted to go digital.

“There are a couple of ways you can approach a digital upgrade,” he said, “from buying a standalone digital console to a full router-based system.”

With the station’s commitment to live music in mind, Pappas preferred the versatility of a router approach. After looking at several options, he decided on a Logitek Numix.

“The system behaves like a giant router in the sense that every input is available to every control surface and every output,” he said. “Because it is software-driven, we can reconfigure it via software. We never have to move an input or output physically.”

The system has 40 digital inputs and outputs and 24 analog I/Os. All are run to a central rack room, where the Numix routing takes place. The control surface “mix boards” run the router via a four-pair CAT-5 cable.

Buying quality

In all of its hardware decisions, Pappas said the station made a conscious decision to buy quality. Even though KUVO, which is licensed to Denver Educational Broadcasting, is a small standalone with only 7,000 members, Pappas wanted to have the best equipment.

“We didn’t want to be shortsighted and outgrow the stuff in four years,” he said. “The directive from management was, buy the best quality and not cut any corners.”

The station’s general manager is Florence Hernandez-Ramos; the program director is Carlos Lando.

“Obviously, you have to have the support of station management. Everyone has to be on the same page working towards the same goal,” Pappas said.

For a station that gets 60 percent of its annual budget from its listeners, this required some patience.

“We spent a couple of years raising funds to put this together. For instance, we evaluated board vendors for over a year before selecting Logitek. We had to make the right choice right from the start, and we used this approach with every item we purchased.”

The overall project budget was approximately $300,000.

The first phase of the rebuild began in 1999 in what had been KUVO’s production room. Pappas and his assistant, John Mikity, moved the old analog production gear to a corner of the live performance studio’s control room while they began building a new studio in the production space.

In addition to the Logitek Numix controller, the new studio space gave KUVO’s on-air personalities a room full of new gear to learn.

“There isn’t anything in the plant that’s older than a year and a half,” Pappas said, from Denon CD players, which play most of the music, to Sony MD players for station promotional announcements, to the Tascam cassette deck for skimmer use.

There is no hard-disk automation system.

“We’re still spinning CDs because I haven’t found an automation system that I liked that actually sounded good,” Pappas said.

The attention to detail extended to the monitors in the new studio.

“You don’t hear about many radio stations using Genelec in their on-air studios,” Pappas said (although Genelecs also were chosen for the recent massive digital buildout at XM Satellite Radio in Washington).

KUVO’s studios each have a pair of Genelec 1029A speakers and a matching subwoofer, “so our on-air people can hear exactly what’s going out over the air.”

Simple switchover

Once the production room had been rebuilt for digital use, it was put into service as the new main air studio, freeing Pappas and his staff to gut the old air studio and rebuild it as a duplicate of the production studio – thus allowing KUVO to switch from one to the other with a simple software download to the Logitek system.

While that task was underway, Pappas turned his attention to the other end of the air chain.

Up at the Lookout Mountain site, the old tube transmitter gave way to a solid-state Nautel FM-10 with NE-50 exciter. The station’s effective radiated power is 22.5 kW, with a transmitter power output of 5.8 kW.

In contrast to the old tube gear, Pappas says he’s been thrilled with the reliability of the Nautel.

“We used to go up to the transmitter site once a week,” he said. “Now I go up once a month, just so I don’t feel guilty, just to knock the dust out of the air filter.”

An additional benefit to using Nautel equipment, Pappas said, is its wide usage in the Denver market. At least six other FM stations are using Nautel, he said, making it easier for engineers in the Mile High City to borrow parts in an emergency.

A Shively 6810BR eight-bay 3/4-wave spaced unilobe antenna was put in place on the KUVO tower. To get the audio from the studios five blocks north of downtown to the transmitter site high in the Front Range, Pappas picked a Harris CD-Link digital microwave system, which KUVO runs uncompressed.

Indeed, Pappas said the plant has little digital data reduction.

“The MiniDisc machines (Sony aand Otari) use compression, and the sat feeds from National Public Radio are compressed,” he said. “We don’t compress anything else, because it kills the audio quality and I can hear it. And that’s all that counts.”

The final touch in the air chain is an Omnia processor, loaded with FM Veris software originally developed by the supplier for Swedish Radio’s classical FM network.

“We don’t need to be the loudest guys on the dial,” Pappas said, “but we do want to have the cleanest signal.”
Fact FileStation: KUVO(FM)

Frequency: 89.3 MHz

Power: 22.5 kW

Format: Jazz

Owner: Denver Educational Broadcasting

Licensed: Aug. 29, 1985

Information: (303) 480-9272 or


President/GM: Florence Hernandez-Ramos

Program Director: Carlos Lando

Chief Engineer: Mike Pappas

Assistant Engineer: John Mikity
Live room

The rebuild of the main on-air studio was finished last September, and Pappas says “about 40 or 50” listeners called to compliment the station for its improved audio quality after the studio and transmitter upgrades.

As for the huge live-performance space, Pappas said he filled it with the best technology he could afford. For microphones, KUVO uses a variety of Neumann and Sennheiser products, including a matched pair of Sennheiser MKH800s (“with 50 kHz response,” Pappas said with pride) and a Neumann KM-100 dummy head for recording percussion.

While the Neumann KMS105 mics in the air studios are fed through Symetrix 528e processors, Pappas prefers to use little equalization on the live-performance mics, instead choosing “just the right mic” from his stable for each instrument or performer.

“We decided to spend our money on the best microphones we could afford instead of buying outboard Band-Aids to try to ‘fix’ lesser-grade microphones.”

Are there special considerations of miking in this kind of radio environment, where live musical performance is common?

“We use a minimalist approch to miking performances,” Pappas said. “For example, we only use three microphones on drum kits – two Sennheiser MKH-20 omnis and a MHK-20 low in the kit. It took us about two years’ worth of experimenting to come up with this configuration. It works so much better than trying to stuff eight or more mics in a drum kit.

“We have also been experimenting with using the Neumann KM-100 on congas and Latin percussion, and it is amazing. We have also been experimenting with using Sennheiser MKH-70 shotgun microphones on reed instruments. You can place them farther from the musician and you get more of the sound from the whole instrument than if you just stick a mic in the bell.

“Almost all microphones we use are condensers, mostly Sennheiser and Neumann. We recently broadcast a live performance of Grammy Award-winning jazz vocalist Dianne Reeves. We hooked her on the Neumann KMS-105. We used a matched pair of Neumann KM-184s on her guitar player’s Romero Lubambo guitar.”

A 24-channel Mackie 8-Bus board is used for mixing live performances, which are recorded on an Alesis ADAT multitrack recorder for eventual use on CDs. KUVO offers the CDs as membership premiums.

Recently, Pappas has been experimenting with Sony’s Direct Stream Digital format, which offers 100 kHz bandwidth, thanks to a unit Sony loaned to KUVO for testing.

“Direct Stream Digital is a 1-bit format that runs a sample frequency 64 times greater than that of a standard CD. It offers wide bandwidth and very high dynamic range of about 120 dB. It records to either hard disk or MO disk.

“We use it to record all of our live performances. We will eventually release a compilation of live performances on the consumer playback format of DSD, which is called Super Audio Compact Disc (SACD). The reason we are recording on this is that it offers the highest fidelity of any digital format and it is perfectly in line with our goal of uncompromising quality.”

Vendor support

Planning and execution of this project were done in-house.

“We did all of the design, purchasing, wiring (the plant is wired with Mogami analog and digital cable) and installation ourselves.”

Pappas said he received “world-class support” from his vendors.

“For example, we got dumb with the Logitek Numix and programmed it wrong the weekend before it was to go on the air. We called Tag Borland, the president, at home and he bailed us out of our self-inflicted problem. Bob Surette at Shively went way over and above the call of duty. John Lynch at Broadcast Supply Worldwide was a huge help when we figured out we were short some critical component and we needed it the next day.

“We had a snag with the Nautel transmitter (again self-inflicted) during the installation, and we called their 24-hour support line at 3:30 a.m. our time on a Sunday morning and got a call back in under 25 minutes.

“And of course the folks at Sennheiser and Neumann who have supported our quest for the best live performance sound.”

The real test of KUVO’s new equipment happens 24 hours a day in the hands of its large staff of air personalities, mostly volunteers.

“We basically went from stone tablets to – as my program director said – the starship Enterprise,” Pappas said.

That required training sessions for the staff, four people at a time, as they learned what they could accomplish in their new studios – for instance, assigning each of the last four faders on the Logitek console to any of 15 audio sources.

Pappas was worried about the reaction, especially from some of the station’s older volunteers, but he learned his fears were misplaced as soon as he heard from “J.C., The Senior Citizen of the Airwaves,” who hosts KUVO’s Friday night blues show.

“She came out and she goes, ‘I can’t wait to get on this thing,’” Pappas said.