Special Features

3-Channel SACD Playback


Published on December 1, 2004

Sigfried Linkwitz is a well-known speaker designer and co-developer of the Linkwitz-Reilly crossover. His latest loudspeaker is the Orion (pictured below), and on his web site he has these observations on some of the new Living Stereo 3-channel SACDs:

Siegfried Linkwitz

A few SACDs and their need for a center speaker

A number of people wrote to me about the reissue of RCA Red Seal Living Stereo recordings in SACD format and the necessity of a center channel speaker for playback. A number of the original recordings were made with 3-track analog tape equipment for playback over left, center and right front speakers. They were mixed down to two channels for LP issue and contained some wonderful classical music performances. Today the original, unprocessed three tracks of these historical recordings can be heard via SACD.
I bought three of the ten available SACD:
1 – Chopin: Ballades and Scherzos, Arthur Rubinstein
2 – Mussorgsky: Pictures at an Exhibition, Fritz Reiner, CSO
3 – Tchaikovsky: Piano Concerto #1, Rachmaninoff: Piano Concerto #2, Van Cliburn
The following are first impressions and observations from comparing playback of the 3-channel recording to the 2-channel CD down-mix which is also on the SACD. I used the center speaker that is described above and which was entered into the AV receiver setup as ‘Small’ for bass management.

1 – The CD tracks are superb on the ‘Rubinstein’. I had listened to them several times and weeks had gone by before I finally took the center speaker out of the garage and set it up again. Well, the SACD and its center channel added a real sense of solidity and body to the piano. Definitely worthwhile. This motivated me to find more of the RCA recordings and I got discs 2 and 3 from the local record store.

2 – The recording quality of the ‘Pictures’ is far below the ‘Rubinstein’. I have not listened to the whole piece. It did not promise to be enjoyable. Track 7, for example, has horrendous modulation distortion. I moved on to disc 3 with trepidation.

3 – The ‘Tchaikosky’ immediately struck me as a clean, natural recording and curiously I switched to the ‘Rachmaninoff’, which is my wife’s favorite music, thinking that I could give her a demo she would enjoy. I was surprised about the difference in sound stage. The three microphones must have been very widely spaced. The string sound is quite unnatural. On the CD cut the phantom image of the piano is swimming in space. The center speaker locks it in place and anchors the sound stage on the SACD cut. I suspect the weakness in image stability is due to small amounts of wow and flutter from the analog tape recorder. On such recordings a center speaker stabilizes the image, but also tends to draw the center stage unto itself, rather than leaving it behind the speaker. Preferably I listen with my eyes closed in order not to get my sonic mental image distorted by the visual presence of the speakers.

All three SACD benefited from using a center speaker, though in different degree. I then switched to two recent SACD recordings:
4 – Orff: Carmina Burana, Atlanta Symphony Orchestra and Chorus, on Telarc
5 – Mahler: Symphony #4, San Francisco Symphony

The first impression after the RCA recordings was one of greater stability and solidness of sound. Also the low frequency end was more realistic in its character. The center speaker seemed to contribute less to the image other than to widen somewhat the ‘sweet spot’ for listening. It also had some benefit in making the soprano in the last movement of the ‘Mahler’ more intelligible, though still not enough to follow the German text. But that is not different from a live concert. With these two recordings, though, the center speaker was visually in the way, because the sonic event was happening behind it. It is much more easy to ignore the left and right speakers as just sitting there and not being part of the sound picture when I listen to a good CD, but having three speakers looming there like a fence, though seemingly transparent, is disconcerting to me and I must close my eyes not to get distracted.

Someone suggested to me to get the Clark Terry, ‘Portraits’ recording on Chesky Records to see if the trumpet can be reproduced with a 1 inch dome tweeter crossed over at a low 1440 Hz as I do for the ORION. This 1988 recording by Bob Katz has been reissued on SACD. The center channel is not used and so in this respect there is no noticeable difference between the CD and SACD tracks. The sound stage is that of a typical studio recording as opposed to the Bucky Pizzarelli, ‘Swing Live’ SACD’s nightclub atmosphere, which to me is more pleasing. The trumpet does indeed tax the tweeter more than on most recordings. For example, playing the ‘Autumn Leaves’ selection of the ‘Portraits’, track 3, at respectably loud sound levels demands around 20 W peak from the tweeter’s dedicated power amplifier. The trumpet is firmly locked to the right speaker, the piano to the left speaker while the bass and drums are located between the speakers with some depth and separate from them. The trumpet sound seems slightly more bodied on the SACD cut. I am quite certain that the trumpet sound character is not modified by tweeter distortion. It appears level independent. Also, I have listened to many other trumpet and brass instrument recordings (e.g. Wynton Marsalis) at high levels without any suggestion of tweeter stress. A 20 W requirement for the tweeter can be quite demanding, though, if a single power amplifier must drive a loudspeaker through passive crossover networks. Then these 20 W must be delivered on top of the simultaneously occurring and usually higher power draw from midrange and woofer drivers. This can lead to clipping distortion and even destruction of the tweeter unless the power amplifier has very high power capability and headroom.

The two mentioned jazz SACD contain fun music and are well worth owning. They are good examples of surround sound without a center channel, where the main purpose of the surround channels is the creation of acoustic space and not the placement of discrete instruments to the side or rear of your room.

My overall assessment for the need of a center channel with the ORION has not changed. If I sit for my critical or fully involved listening in the stereo ‘sweet spot’, the apex of an equilateral triangle, then the contribution from the center speaker – as compared to a phantom center – is marginal. I only found it worthwhile for the historic RCA recordings. If I listen from a greater distance, then the reverberant sound in the room becomes too dominant for the center speaker to make a significant difference. If I sit off to one side, then the sound is pulled less strongly to the near speaker, but that does not turn it into a place where I would sit to listen attentively, because the sound stage is too distorted.

For the time being I will leave the center speaker in my listening room rather than returning it to the garage. I have moved it off to the right where it is mostly out of sight. I can easily place it back in the center should the need arise. But I suspect this setup will not last.

www.linkwitzlab.com




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