I actually have IBOC capability on my home receiver (the Yamaha
RX-V4600). The "mutlicasting" on FM is actually pretty nice since it
allows commercially-untenable formats to be broadcast. Here in
Detroit, we have 9 stations broadcasting "second IBOC" channels. One
(94.7) uses its second IBOC channel to broadcast "deep album rock"
from the 1960's and 70's. Another (105.1) broadcasts classical "pops"
on its second IBOC channel. Another broadcasts "live rock concerts"
on it's second IBOC channel.

The audio quality on the FM IBOC channels is about as good as a 256K
MP3. An analogue FM transmission is capable of MUCH better sound
quality (although only a few stations such as WFMT in Chicago or WQXR
in New York actually broadcast uncompressed FM analogue sound).

The big problem, reception-quality-wise, is that FM IBOC is
unreceivable unless you are in a strong, local reception condition.
For example, there's an NPR station that broadcasts classical music in
Lansing, MI (about 80 miles from me) and I can't pick up their IBOC
signal, even with a yagi directional FM antenna. Their analogue
signal comes in just fine, and my receiver reverts to analogue since
the digital IBOC signal is unreceivable.

As far as AM IBOC goes, Detroit's 950 AM and 910 AM broadcast an IBOC
signal. 950's audio quality was HORRIBLE when it first started up,
with echoey, swishy, digital artifact sound. Now, Ibiquity seems to
have fixed something and 950's signal sounds okay with nice high
frequency reproduction. It sounds about as good as a 64K MP3. 910's
IBOC signal still sounds awful (although it's in stereo).

AM IBOC though does NOT in any way, shape, or form have "FM quality
sound" as Ibiquity's advertising trumpets.

There is an AM stereo station locally (CFCO in Chatham, ON) which
indeed DOES have "audio quality approaching FM" when listened to on a
good AM stereo receiver (I have an AM stereo tuner in my Ford Escape
Hybrid which has the best sound that I've ever heard out of an AM
radio).

As far as "IBOC vs DRM" for "high fidelity AM" broadcasts, since IBOC
"shares" the allotted bandwidth with an analogue signal, it requires
an extremely strong local signal in order to receive it. There is an
AM NPR station in Lansing, MI which is UNRECEIVABLE in IBOC mode from
70 miles away, even using a Kiwa Air Core Loop which brings in the
analogue AM signal 20 dB over S9. In contrast, since DRM does not
share it's bandwidth with an analogue signal, the ability to "DX DRM"
is much greater. I can receive DRM test transmissions with perfect
decoding from stations that are inaudible in analogue mode (Deutsche
Welle and Radio Nederland quite often "switch over" from analogue to
DRM in the midst of a broadcast).

As far as "Eureka DAB" goes, it's deader than a doornail in Canada.
The foppish bureaucrats who were trying to "act European and declare
their independence from the U.S." by implementing DAB in Canada failed
miserably and wasted millions of Canadian tax dollars in the process.
Since most Canadian stations (except the CBC) are dependent on U.S.
advertising, absolutely NONE of them were about to replace AM and FM
with DAB and lose all of the U.S. advertising dollars. I spoke with
an engineer at the local CBC station in Windsor, ON and he didn't even
KNOW that there was still a DAB transmitter operating in Windsor.
The Canadians quietly abandoned their ill-conceived DAB pork-barrel
and have allowed XM and Sirius to begin service in Canada.

The above comments are based on empiricle results from my own
listening and DX'ing experiences using analogue AM Stereo, IBOC, and
DRM receivers.

Fred E. - N8UC
Detroit, MI