Yamaha Home Theater mind boggling

Electronic News, Feb 17, 1997 by Joyce Putscher

There were many great products at the Consumer Electronics Show last month, but the product that was the most memorable to me and "blew my hair back" was the Home Theater from Yamaha. The Yamaha Dolby Digital receiver featured in this home theater, model RX-V2092, was priced at $1,599.

Previously, I didn't think in terms of semiconductors whenever I came across the name Yamaha. Instead I thought of a musical keyboard, a stereo receiver...or my Yamaha 125 street bike from many years ago.

Now that's changed. Instrumentally behind this receiver's technology is Yamaha's own DSP chipset that performs Dolby Digital, Cinema DSP and Digital Sound Field Processing. Although Yamaha's microprocessors are sold to a variety of manufacturers for use in electronic components, the company primarily supplies its chips for its own products. Although I normally follow the merchant market, I found this chipset very compelling.

This chipset consists of their 24-bit Dolby Digital decoder YSS243 ASIC-DSP, and their Cinema DSP with Tri-field processing, the YSS245. Tri-field processing simply translates to three sound fields in a room--the front (left, center and right speakers), left back and right back. Yamaha's YSS245 also takes care of Pro-Logic decoding and Digital Sound Field Processing (Cinema Sound Field Processing, or CSFP). CSFP enables the listener to hear an artist perform in his/her favorite venue, with the associated sound-field characteristics of each--such as live performances in the Roxy Theater, Anaheim Stadium or a cathedral. The YSS243 is available for licensing (Yamaha Systems Technology in San Jose, Calif.), but the YSS245 is for internal Yamaha use only.

Two major goals in AC-3 Dolby Digital signal processing are to preserve the placement of sounds of the recording engineer, and to acoustically enlarge the size of the room to simulate a theater. The Dolby Digital chip preserves the placement of the sounds, while the Cinema DSP chip performs the acoustic enlargement function.

Yamaha developed their own chipset rather than use general-purpose digital signal processors. (Yamaha fabricates their DSP chips at their own facilities.) The company maintains that general-purpose chips do not perform certain audio functions as well, since they are not tweaked for high-end audio. They state that general-purpose chips waste chip space for functions not used, resulting in lower performance than could be achieved by a chip focused on only high-end audio processing. The YSS243 only needs a 20MHz clock for high-performance throughput and is designed for low power consumption. This view could, of course, be argued--pointing out that there are single-chip programmable DSP family derivatives that are specifically targeted toward Dolby Digital for home theater, like Motorola's DSP56009 and Zoran's ZR38500.

Dolby Pro-Logic offers mono surround sound while Dolby Digital offers stereo surround sound. Right now, Dolby Digital (AC-3 digital surround sound) is confined to laser disks and digital versatile discs (DVDs). However, a myriad of video tapes currently provide Dolby Surround, which is decoded as Dolby Pro-Logic (if your receiver is Dolby Pro-Logic capable). In the future, support will hopefully expand to include Dolby Digital within the signals received from Digital Satellite Systems.

This chipset enables Yamaha's home theater to virtually create a movie theater experience while you enjoy the comfort of your own sofa. I actually got goosebumps when I listened to their movie clip demo (seven speakers were used). This demo I am describing did not take place in their secluded demo room; it was out on the show floor in their mock living room set-up. Now I'm the type that would not normally even consider spending more than $500-$600 on a good TV, let alone amass a home theater. But I must admit that the experience has stayed with me since the show. When I think of all the movies my family rents instead of going to the theater, this could be a possibility after all. Depending on the price of a complete speaker setup and when the receiver price comes down a little, I just might have to get serious about it.