Though BMInt and its readers have for some time rued the loss of the live Friday afternoon broadcasts of the Boston Symphony Orchestra, we are very happy to acknowledge that WCRB and Classical New England as well as the BSO itself have greatly expanded the possibilities for listening to the BSO’s Saturday night performances. There are now 12 different ways to tune in, and Classical New England is about to announce a 13th. BMInt is very curious about this plethora of signals. So we began by asking the BSO’s Director of Public Relations Bernadette Horgan why the BSO and Classical New England offer exactly the same on-demand concerts on their respective sites and what the BSO is planning for the web.
Since WGBH and the BSO each have their own online visitor base, it makes sense to offer the broadcasts through both sites in order to capture the greatest number of listeners most passionate about the BSO’s online concert recordings. At present, this makes the most sense, but since the possibilities for disseminating content are always changing, we’re regularly reviewing the options on how to best reach both our actual and potential audience for recorded online concert content.
It was only last April when the BSO announced that it would offer online streaming of BSO, Pops, and Tanglewood concerts on its site, www.bso.org., in partnership with 99.5 Classical New England—a big step for any performing arts organization. Following on that success, we’re now in the planning stages of defining the BSO’s next step in providing additional online performance content, though we won’t have anything new to announce on this subject until we’ve completed that process. That being said, any further steps in online content need to be carefully considered in relationship to the orchestra’s primary focus on the live concert experience, the cost-profit ratio involved in providing additional online content, and any additional fundraising measures that might be needed to support any possible new offerings.
Classical New England’s Managing Director of Classical Services Benjamin Roe responded:
As far as I’m concerned, the more opportunities that listeners have to access BSO broadcasts, the better it is for both organizations. One thing we’ve learned in the world of digital media is that it’s not a zero-sum game, e.g., one organization’s success is not another one’s loss. Opening pathways to experiencing the excellence of the Boston Symphony Orchestra in a live performance setting—which, in my view, includes the quality of the broadcast recording, production, and commentary—is also why we’ve revived a syndication network of public radio stations around New England, and actively pursued the occasional opportunities to share these concerts on both a national and international basis with NPR, American Public Media, and such European broadcasters as the BBC, France Musique, and ORF (Austrian Radio).
To help our readers navigate our dozen local choices, we enlisted the help of the Boston Audio Society (BAS), an independent nonprofit member-supported organization promoting the highest quality of music reproduction and home theater as well as high standards in recording and transmission. Longterm BAS members Stephen Owades (who happens also to be a 43-year veteran of the Tanglewood Festival Chorus) and John S. Allen prepared the following report based on their and fellow members’ exhaustive analyses. [FLE]
BAS members identified, digitally recorded, auditioned, measured and reviewed 11 different transmissions of the Boston Symphony concert from October 13 th, Mendelssohn’s Violin Concerto and Shostakovich’s 4th Symphony. Owades collected the different versions and analyzed them for dynamic range and frequency content.
The 11 sources are as follows:
- live (Saturday night) via WCRB-FM 99.5 (analog FM stereo)
- live (Saturday night) via WCRB-HD 99.5 (96kbps Ibiquity digital)
- live (Saturday night) via WGBH-HD2 89.7 (48kbps Ibiquity digital)
- live (Saturday night) via WGBH web stream (128kbps MP3)
- delayed (Sunday afternoon, following weekend) via WCRB-FM 99.5 (analog FM stereo)
- delayed (Sunday afternoon, the following weekend) via WCRB-HD 99.5 (96kbps Ibiquity digital)
- delayed (Sunday afternoon, the following weekend) via WGBH-HD2 89.7 (48kbps Ibiquity digital)
- delayed (Sunday afternoon, the following weekend) via WGBH web stream (128kbps MP3)
- on-demand (beginning a day or two after the concert) via WGBH on-demand stream (128kbps MP3) Boston Symphony in Concert
- identical to above except via BSO Media Center (128kbps MP3) ((not part of test but cited as duplicate—more elegant interface than above))
- on the “continuous loop” BSO Concert Channel via WGBH stream (192kbps MP3)
- and the master recording, kindly furnished by WGBH for comparison purposes (PCM digital)
At the December meeting of the BAS in the spacious listening room of a member who has high-quality, smooth and wideband playback equipment, we listened in stereo, using only one speaker each for the right and left channels, plus a subwoofer. Owades played the same excerpt from each version, and asked attendees to write down comments without knowing which was which. Following the listening session, Owades revealed the sources of the excerpts and showed graphic displays of waveforms and frequency spectra. He also showed a table comparing the dynamic range of the different versions. His clear conclusion, supported by the comments, was that the on-demand and Concert Channel streams were both substantially better-sounding than any of the live or delayed broadcasts and streams. The latter suffer the dynamic compression used for everything that goes through the main signal path at WGBH. Owades’s measurements in fact showed that the WCRB analog signal, for whatever reason, had substantially less compression than the other broadcast signals.
Owades and many other BAS members don’t necessarily fault WGBH for its choice to compress certain broadcast signals, since many people listening casually or in noisy environments may well prefer the compressed version (which is done pretty well). But if you want to hear these concerts at their best, the on-demand and Concert Channel streams are definitely the way to go. These streams have the same dynamics as the master recording, and sound essentially identical to it.
The HD broadcasts appear to suffer some further audible degradation due to their low data rate, especially the WGBH HD2 broadcast, which shares digital bandwidth with the main WGBH program and has half the data rate of the WCRB HD signal.
The usual way to reduce the data rate of digital audio is to omit frequency bands which are quiet enough that sounds in other bands are judged to mask them, also to adjust the precision of encoding in bands which are transmitted. HD radio uses another, extraordinary method: all frequencies above 8 kHz are synthesized. This was obvious in the spectral displays, where they had a different appearance from lower frequencies. The encoding and synthesis apparently resulted in a treble rolloff, noticeable in the WGBH HD2 signal—though that remains to be confirmed: it also could possibly have resulted from the tuner and recorder which captured that signal.
An important feature of the digital signals, however, is that they are noise-free, and that the WGBH HD2 signal is strong in areas south of Boston and behind hills, where the WCRB signals—both digital and analog—are weak. Digital signals never distort due to multiple signal paths, and can bridge noise pulses and short signal dropouts without audible loss. Digital reception, of course, requires a digital receiver, and it is also very much an “all or nothing” proposition. As an analog signal weakens, it gets noisy in stereo, must be switched to mono to quiet the noise, and then finally turns noisy even in mono. A digital signal is either received well or not at all. In a moving vehicle, or with a marginal signal, digital reception may be intermittent. On WCRB HD or WGBH HD1, a tuner will switch to the analog signal if the digital signal becomes too weak; there may be some audible glitching as it switches. On WGBH HD2, the tuner will go silent, because there is no analog backup for the second HD signal.
Analog FM stereo is bandwidth-limited to 15 kHz, to maintain a guardband between the baseband mono signal and stereo separation signals. Somewhat to Owades’s surprise, all of the Internet streams also were lowpassed at 15 kHz, though there is no technical need for this. The bandwidth restriction would not be noticeable to listeners. Only the master recording preserved signals up to the limit of (unimpaired) human hearing.
The on-demand channel has a lower data rate than the Concert Channel, and so, at least theoretically, is less faithful to the master, but it is far more user-friendly. Brian McCreath of WGBH has told Owades that WGBH has “re-architected” the BSO Concert Channel. It is still a continuous loop of one concert after another, but it now contains only the music portion of each BSO program: no announcements, extended applause, or features. There is metadata identifying and elucidating the performances embedded in the stream, but most players and apps can’t read this metadata, and thus, since one can’t identify what one is hearing, the Concert Channel is suited chiefly for background music even though it’s the best-sounding option of all. An iPhone app called “TuneIn” is able to display a portion of the metadata for that channel (the work and composer), but not the performers or performance date. So if you want to listen to a particular piece from a particular concert, the BSO Concert Channel will be of little help.
BAS members have also recorded all the live and delayed broadcast versions of the Verdi Requiem broadcast of January 19, 2013. These will be reviewed along with the master, on-demand and Concert Channel recordings at the society’s upcoming meeting at the WGBH Fraser Performance Studio. Multiple recordings were made of WGBH HD2, so it will be possible to determine the reason for the treble rolloff. A detailed summary of both meetings will be published in the quarterly BAS newsletter, the BAS Speaker, available to members in print or electronically (selected back issues are electronically available to the public).
More information about the Boston Audio Society, including dues and times and location of upcoming meetings, is here.