The onscreen menus offer myriad setup options, yet we never got in so deep that we lost our way. For a receiver as well-endowed with features as the TX-SR604, everything is exactly where it ought to be, except for one thing: the onscreen menus don't appear over the HDMI. You can either connect another cable (component, S-Video, composite) to navigate through the setup chores or navigate using the LCD display on the receiver--which can look pretty small if you're sitting far away. Yes, the speaker setup and calibration are handled by the Audyssey 2EQ, but you still have to navigate the menus to assign inputs and deal with minutiae (the receiver's factory default HDMI audio is Off, requiring you to search through the menu to activate it). Of course, if you're not using the HDMI output this won't be a problem, but if that's the case, you should probably save some money and opt for the step-down model, the Onkyo TX-SR574.
The Audyssey 2EQ automatic auto-speaker-calibration system is the best ever offered by Onkyo, but it requires the user to run the setup program from three different positions in the room. It's easy enough to do--just plug in the supplied microphone, then respond to the onscreen prompts. After the Audyssey finishes sending test tones, the receiver automatically adjusts the speaker size settings, the subwoofer crossover points, the channel volume level, and the time delay settings for each speaker. The system is accurate, so we'd recommend using it. The Onkyo TX-SR604 is a 7.1-channel receiver that dishes out 90 watts per channel and offers the usual assortment of Dolby Digital, Dolby EX, Pro Logic IIx, DTS, DTS-ES, DTS Neo:6, DTS 96/24, and Neural surround processing modes. There's a total of five A/V inputs with S-Video (including the front panel set), plus three component video and two HDMI inputs. The HDMI connection carries Dolby Digital, DTS, CD, DVD-Audio, and uncompressed PCM audio--as well as high-def video--between the source and the receiver, so you won't need to hook up a digital audio cable. While the TX-SR604 will convert composite and S-Video sources to component video output, it will not do analog-to-HDMI video conversion. Thus, as mentioned above, HDTV owners will need to run component and HDMI cables to their set.
We counted six digital audio inputs (two coaxials and three opticals on the back panel, one optical up front), and one optical digital output. Compatibility with Blu-ray, HD DVD, or SACD/DVD-A players should be guaranteed, thanks to the HDMI inputs and 7.1-channel analog inputs. Like every receiver currently available, it cannot decode the new highest-resolution soundtracks (Dolby TrueHD and DTS-HD Master) on Blu-ray and HD DVD discs, so make sure your high-def disc player can decode these formats internally, if that's important to you. There's also one stereo analog input, plus a tape in/out set for use with a cassette or CD recorder. XM Satellite Radio, including XM's Neural Surround, is available with the addition of an XM Mini Tuner/antenna and a subscription. The RI (Remote Interactive) jack can be used with Onkyo's DS-A1 or DS-A2 iPod docking units. There are also high-quality speaker binding posts for seven amplifier channels. One final note for analog purists: there's no phono jack, so you'll most likely need to invest in an external preamp to enjoy your record collection.
The TX-SR604 doesn't offer switching for a set of B stereo speakers, but if you're using only five of the receiver's seven channels, you can hook up a set of stereo speakers to the Zone 2 speaker connections. The arrangement is actually better than B speakers because you can listen to a different source--say, the XM radio in Zone 2--while someone else is watching a DVD in the main room. Other multiroom connectivity options include stereo audio outputs, as well as infrared and 12-volt trigger outputs.
One important note to prospective buyers of this receiver: it's also available as part of the Onkyo HT-S907 home-theater-in-a-box kit. For an extra $500 ($1,000 total), you get the Onkyo SKS-HT740 7.1-channel speaker package and the Onkyo DV-CP704 DVD changer. For anybody looking to start a home theater from scratch without spending a fortune, it's a pretty great deal. Auditioning the Onkyo TX-SR604 reminded us again that Moulin Rouge is one of the best sounding DVDs we've ever heard. The sound is remarkably transparent and clear, with thrilling musical dynamics--the dialog is natural and then--wham!--the music swells up and up as the orchestra plays. Onkyo's sound is pretty neutral and well suited to bring out the best from a wide range of speakers. CD sound was also first-rate; the bass was powerful, and the midrange and treble were pure.
We also took a listen to the TX-SR604 as part of the aforementioned HT-S907 home-theater-in-a-box system. The TX-SR604 continued its strong performance when we fired up the Mission: Impossible III DVD. The helicopter chase sequence in the field of windmills--with rockets firing and things blowing up every minute--places enormous demands on the system, so sure, we detected the satellites straining to keep up, but that doesn't mean the TX-SR604 wasn't up to the task. When the action level scaled back in the scene where Tom Cruise enters Vatican City, the Onkyo system sounded full-bodied with impressive dynamic range, and dialog was beautifully balanced and natural.
The TX-SR604 also sounded good as part of the HT-S907 on music. The HT-S907 did a great job on Led Zeppelin's eponymous DVD; the huge surround mix filled our home theater, and the front three speakers' soundstage had a nice sense of depth. Jimmy Page's raw guitar distortion sounded great, as did Robert Plant's vocals. We changed over to CDs--where many HTIB receivers struggle--but again, the TX-SR604 shined. The receiver did a fine job with CD audio, as the satellites' sound was certainly crisp and clear on jazz pianist Hank Jones' West of 5th CD. The subwoofer provided musical bass that was free of boom or bloat. With larger speakers, it's a safe bet the TX-SR604 would sound even better.