New York - iBiquity Digital vows to improve the AM-band performance of its PAC audio codec in time for digital-radio receiver launches planned for later this year, but that timeframe might be overly optimistic.
That's because iBiquity had been upgrading its PAC codec for almost year when AM broadcasters raised another round of concerns in late April during an iBiquity-sponsored demonstration for broadcasters, receiver makers and trade associations.
Before the April demo at NPR studios, Kenwood planned August shipments of a car receiver, Audiovox planned '03 aftermarket car radio shipments, and Delphi was ready for calendar 2003 shipments of an OEM radio for 2004 model-year-vehicles. Home radio shipments were planned by Kenwood, Harman Kardon and Yamaha for this year.
iBiquity's latest effort to improve AM PAC's performance started after the April demo and after the National Radio Systems Committee (NRSC) temporarily suspended standard-setting efforts for iBiquity's digital AM/FM technology.
The NRSC decision followed complaints by select AM broadcasters about the sound quality of the in-band on-channel (IBOC) technology's audio codec at a 36kbps bit rate. That bit rate is needed to squeeze a stereo audio program into an AM station's constricted bandwidth. PAC's FM-band bitrate, in contrast, is 96kbps.
The previous effort to improve AM PAC began more than a year ago after April 2002's NAB show, where AM PAC was demonstrated to the industry at large for the first time and was criticized by AM broadcasters. At the time, iBiquity had just integrated PAC into its field-tested RF technology for the first time and knew that PAC improvements were needed, said iBiquity marketing VP Dave Salemi. "There have been tremendous improvements since then," he said.
iBiquity made codec improvements between April and August of last year, conducted subjective listening tests in August, and handed over the results to the NRSC on Oct. 15 for review, Salemi continued. On February 6, the NRSC's evaluation working group met for the first time to consider the results. At that meeting, however, iBiquity withdrew the report, contending that it had advanced the codec four to five generations beyond what was tested for the report, said David Lehrer, NAB's advanced engineering director.
In early April, iBiquity staged demonstrations at the NAB convention of its latest generation codec, then in late April, the company held demonstrations at NPR facilities. At the NPR demo, said Lehrer, broadcasters still voiced concerns over 36kbps PAC. Broadcasters, he added, still haven't heard AM PAC at a 20kbps rate. That's the data rate at which radios would receive digital AM mono in challenging signal conditions.
"We've always been told we must make it better," but select broadcasters "say we're still not quite there yet," iBiquity president Robert Struble said. "Our hope is that any change will be compatible with the current [receiver] rollout schedule."
In early June, Salemi told TWICE that a PAC upgrade could be completed over the next two to three months to meet that schedule. He said he was optimistic because "we're a codec-technology company." iBiquity, he noted, provided Sirius Satellite Radio's compression technology and developed several studio-level enhancements during the past 18 months without making Sirius receivers obsolete.
Hardware compatibility: A timely PAC-enhancement decision would be compatible with Kenwood's receiver schedule because a PAC upgrade would require no software or hardware changes to existing receiver designs, Kenwood senior VP Bob Law said. If the codec is changed to a completely different codec, however, new receiver hardware will be required, postponing Kenwood's car audio shipments until next year.
At this point, Yamaha said it doesn't know if it will be able to go through with plans for fall shipments of a home receiver.
At Audiovox, Prestige-brand national sales manager Fred Roetker contended that any decision occurring "much later than 3 months [from now] could certainly jeopardize us getting product out on the market before 2004." If the decision is made in a timely manner, he said, Audiovox could ship either a PAC- or AAC-equipped head unit late this year.
Other suppliers who announced 2003 shipment intentions couldn't be reached for comment.
If the upgrade process drags on too long, aftermarket autosound production cycles could push the first car receiver shipments into 2005, Kenwood's Law warned. A codec decision must be made soon so that autosound suppliers can introduce their 2004 lines at next January's CES, he explained. Introductions postponed until 2005, he contended, could give digital satellite broadcasters another year to year and a half of momentum, and by that time, "digital AM and FM might not have much meaning to consumers, dealers or suppliers."
Alpine marketing VP Steve Witt said he needs a codec decision by August in order to ship Alpine car receivers in time for next year's aftermarket selling season, which begins in April. A decision that drags out longer would push back shipments until late 2004, if Alpine wanted to ship at all during off-season, he said.
Broadcaster rollout: While iBiquity tweaks, rollouts of digital broadcast equipment continue, the company said. That's because software upgrades at the station level can be made to enhance the PAC codec or potentially replace it with the AAC codec, said iBiquity senior VP Jeff Jury explained.
Although Struble stressed that "our intent is to improve PAC, not to switch to AAC," he also admitted that the company is "pushing the limits of science" by implementing PAC at 36kbps.
iBiquity stressed that not all AM broadcasters have questioned the AM PAC codec and that no other attributes of its IBOC technology are in question. Those include AM/FM coverage, FM sound quality, and AM/FM reception performance, including the virtual elimination of multipath, static, hissing, popping and fading.
Kenwood's Law said some AM broadcasters complained of digital artifacts, such as ringing or edginess, in some circumstances. Some broadcasters thought AM audio sounded "warbly" on occasion, Struble said.
Nonetheless, some AM stations are going online with its IBOC technology, which in its current form is still far superior to today's analog AM, according to Salemi, Law and Yamaha sales VP Steve Caldero. Law said he has heard PAC AM on many occasions in different parts of the country and said it delivers near-FM quality, although the technology's advocates promised FM quality.
Broadcast interests, however, said they'd prefer to wait. Milford Smith, chairman of the NRSC's DAB subcommittee, "There is something pretty close to unanimity among those [broadcasters] who have heard it." The concerns come from modest broadcasts groups of 20-30 stations and from the largest groups, including Clear Channel and Infinity, he said.
During the demos at NPR studios, he noted, the AAC codec over AM was demonstrated, "and speaking for myself, AAC was rather significantly better."
Said NAB's Lehrer, "The real danger is getting something out there that consumers won't accept."