Moore's Law, postulated in 1965 by Gordon Moore, co-founder of Intel, suggested that the rate of advance and complexity of semiconductors would double every 18 months. Stated another way, rapidly advancing technology would lead to more affordable electronics. Moore's Law has certainly been proven true in personal computers and wireless communications and I would suggest that home theater has benefited from the same theory, even though home theater didn't even exist in 1965. It seems that each new product cycle brings components, such as A/V receivers, with better features, more power and greater capabilities than the previous generation at a lower price. There is almost no reasonable comparison between the A/V receivers offered ten years ago and models available today. You get a lot more for your money today. When asked to review the Onkyo TX-SR503 receiver, I guessed that the retail price was probably in the $400-500 price range. I was wrong: It has a suggested retail price of $299! With 75 watts for each of the seven channels, most of the decoding formats you'll need, and other features, it begs the question: How well does it perform and how good does it sound?
I had no particular expectations prior to listening to the TX-SR503, but after connecting it to my 5.1-channel system and playing a few of my favorite selections I was pleasantly surprised. The overall stereo sound quality was well balanced with bass response that was full, although it lacked a tight, punchy quality that bass ought to have, and it exhibited a very warm and open midrange, especially with vocals, and reproducing high frequency details cleanly. On first impression it was a good sounding receiver, capable of driving my Paradigm Reference Studio 100 front speakers.
Further listening did reveal a weakness, specifically in the lower frequencies. Rod Stewart's stereo rendition of "'Till There Was You," from As Time Goes By… The Great American Songbook: Volume II [J Records] includes several passages with an octave of bass that extends very low (probably below 30-40Hz). The Onkyo did its best to reach the bottom, but missed the mark. When the same selection was played with the receiver's crossover frequency set to 100Hz (instead of 60Hz) and while using a subwoofer, the system reproduced the lowest bass frequencies. Very deep bass can really tax a receiver's power supply and, with only 75Wpc, it's probably best to use a sub to reach the lowest frequencies and let the receiver handle the rest, which it does very well.
At the other end of the frequency spectrum, the Onkyo receiver really delivered. Midrange and high frequency reproduction had characteristics usually found in more expensive electronics. At low and moderate volume levels the receiver exhibited a very clean and open sound quality with distinct imaging and soundstaging as well as crisp highs. The Onkyo revealed many subtle vocal and instrumental details on Nickel Creek's "Speak" from This Side [Sugarhill Records, SACD]. Perhaps this is due to Onkyo's WRAT (Wide Range Amplifier Technology) design, which has frequency response ranging from 10Hz to 100kHz (+1dB, -3dB). The Onkyo TX-SR503 was also very good at separating the various elements of complex music, as it demonstrated with Nickel Creek's "Out of the Woods" from the band's eponymous Nickel Creek [Sugarhill Records, SACD]. This Irish folk group combines several string instruments with multiple harmonic vocals that can become smeared into one image by some receivers. Not the TX-SR503—the receiver maintained a stable image and soundstage, even during complex passages. This was the case when using the receiver's own DACs (digital to analog converters) or the DACs built into my reference universal player (Yamaha's award-winning DVDS2300). In fact, the receiver's DACs seemed to rival the quality of those built into the player (which is saying a lot, given that the player cost more than three times the price of the receiver).
The receiver proved to be very capable in reproducing multichannel audio as well, creating soundfields that were full and enveloping with pinpoint positioning of various musical elements. Spyro Gyra's "The River Between" from In Modern Times [Telarc SACD], sounded very good with exceptional detail and clarity.
The Onkyo performed equally well with multichannel film soundtracks. One of the best tests of a receiver's surround sound capabilities is the film Master and Commander - The Far Side of the World [Universal], where the music is enveloping, enhancing the mystery and suspense in the story, and the sound from the battle scenes is very realistic. The receiver did a good job of separating the music from the effects, even during complex parts of the action. But the best test of realism is the scene filmed in the ship's hold, where you can hear the creaking of the ship's hull and the crew's boots stomping on the deck overhead. The receiver accurately positioned the sound of the crew above as if someone were running on my roof.