Denon AVR-X6400H Receiver Review
By Chris Heinonen on
The Denon AVR-X6400H is the best receiver for powering 11 channels without the need of an external amplifier or spending a small fortune. Beyond that, the AVR-X6400H includes Audyssey XT32 room correction, integrated HEOS streaming for Spotify, Tidal, Alexa control, and a plethora of HDMI inputs. For a single-box 11-channel solution, the Denon X6400H covers every base and sound great doing it.
Easy, Intuitive Setup
Every time we use a receiver from Denon we come away with how impressive their setup routine is. A bright, colorful on-screen GUI walks you through every aspect of your system setup, from connecting wires to the position of your speakers. It helps you dial in the level of the subwoofer correctly before you calibrate, which many systems don’t do correctly and ensures that your inputs are correctly assigned. The one task it didn’t do well in my case is renaming all the inputs to what their devices are, but I usually handle that through the web interface you can access for Denon receivers. This can be done with the iOS app as well, and then you get to use a keyboard.
Unfortunately, the web interface isn’t available at this time, but Denon has said it will be with a firmware update in the future. Once available, you can use a web browser to access all your settings, rename inputs, and otherwise setup the receiver. Even without this, setting up the Denon X6400H took me under an hour, including connecting devices, connecting speakers, and running Audyssey XT32 for my room. With a 5.1.4 system with 8 HDMI devices, that is easily a record and shows how well designed the Denon AVR setup routine is.
While many companies have moved to using room correction systems that come for free with chipsets, Denon has continued to use Audyssey. The performance of XT32 has continued to improve, and the addition of the Audyssey app has made it far better. Previously to customize the XT32 calibration you needed to have access to the expensive calibration kit but now a $20 app can serve the same role. You can set your EQ range, so it only works up to a certain frequency range. For my use, I chose an upper-limit of 500Hz which lets the Denon correct for bass issues but not change the midrange sound of my KEF speakers.
The app also lets you save and upload multiple profiles, so you can compare different setups without needing to redo the calibration. The one feature I wasn’t impressed with from Audyssey is the LFC or low-frequency containment. When enabled, it’s designed to keep bass energy from leaving your room. In practice, this just sounds like there is no bass in your system at all. I found myself disabling it and leaving it off when the X6400H was in my system.
Fantastic Sound Quality
Over a couple of months, I put the Denon through its paces with a huge number of Atmos 4K discs, along with the Dolby Atmos releases of REM’s Automatic for the People and INXS’s Kick. Since most people will be watching more Atmos films than audio, I’ll begin with my focus there. Watching The Dark Tower or War for the Planet of the Apes, the quality of the X6400H is quickly apparent. Sounds move seamlessly between channels, from surrounds to heights to fronts, without shifts in volume or tone. During intense battle scenes with bullets flying around or quiet scenes with ambient sounds, the Denon perfectly places you in the center of the sound environment.
The Atmos discs for music are even more impressive. The artists have gone back and placed sounds for two of my favorite albums in discrete channels. The engineers have taken different approaches, with Automatic for the People being a bit more subtle, perhaps as they’ve had a previous DVD-Audio release to try to offer a different experience from. The Kick release is more aggressive with placing instruments all around you, but also offers a deeper look into the album than Automatic for the People does. The distinct elements of the album are easier to hear and details you didn’t hear on the original CD are easier to pick out now.
Playing these classic albums as loud as I wanted, with every channel being used for dynamic music and not just some ambient sound effects in a film the Denon never strains. My KEF in-wall speakers are THX-certified and have a nominal impedance of 4 ohms. They aren’t electrostatics but they aren’t a horn driver either, and the Denon pushed them quite easily.
Moving back to films, the integration between the in-wall KEF speakers and the subwoofer is fantastic. While Dunkirk might lack a Dolby Atmos soundtrack, the soundtrack is as good as you can get for 5.1. The opening scenes are filled with intense gunfire and a beach bombing that echo in the room but draws no attention to the subwoofer. There is no overhang or excess energy as SubEQ on the X6400H has done a wonderful job of eliminating those room modes.
Having Spotify and Tidal integrated, along with AirPlay and Bluetooth to handle any other streaming services, makes it easy to listen to music on the Denon. Some receivers make you use an on-screen interface to stream, which is both unnecessary and something I don’t like doing with my OLED or plasma displays. With the HEOS app, it is easy to stream to the Denon, and Spotify Connect makes it even easier. You can control the volume directly from your app, something you can’t do when using an external streaming device like an AppleTV.
Of course, most content isn’t mixed in Dolby Atmos or DTS:X yet. Even the recent 4K Blu-ray releases for Christopher Nolan films, including Interstellar, only pack 5.1 channel soundtracks. Played back on the Denon X6400H using DTS Neural:X however, it uses all of the additional channels on your home theater and does a great job. When there is a dust storm during the baseball game early in the film, the Denon manages to place you in the center of it with winds moving all around you. While doing this it keeps the vocals clear and anchored in the center of the room, making it almost as good as having been mixed in DTS:X or Atmos from the start. While I consider myself a purist when it comes to audio and video, I leave Neutral:X enabled for all movies and TV that I watch as it does such an effective job.
Denon has also added an Alexa skill for their networked receivers this year. For listening to music, it works well as a simple “Alexa, play Radiohead on Theater” lets me start it in my system. Given that I use Alexa all the time to listen while cooking or doing other things around the house, this is one feature I’d take advantage of a lot. Since my theater room is also my office, I listen to music on the system constantly, but this wouldn’t be as useful for people that have a theater they only watch movies in.
Nits to Pick
Usually, I have a few clear issues with products that I’m reviewing and it’s easy to write this section. On the Denon AVR-X6400H, I don’t have any that stand out. The web interface issue would be one that I’d like to see fixed, but that only affects the setup which is already ahead of the competition. I also was less impressed with Audyssey LFC in-use, but that’s easy to disable and could be useful for those in apartment or condo settings where bass traveling into adjacent units is a large issue (we’ve all been there).
I guess it’s also a bit annoying to have to adjust everything on a per-input version sometimes. Once I realized that I didn’t want Audyssey LFC enabled, I had to go to each input manually and disable it. It’s the same with video processing and other features, but in most cases, this is a good thing so your music sources can have different settings than your video ones.
The only thing I couldn’t test with the Denon was the multi-sub calibration in XT32, which is one thing I hope to remedy soon.
Denon AVR-X6400H Conclusions
At the end of two months using the Denon AVR-X6400H, I would be quite happy to leave it in my system permanently. It offers every feature you need today and sounds just fantastic in use. It performs superbly with Atmos and DTS:X soundtracks, but also does a wonderful job with stereo music or remixing your 5.1 and 7.1 soundtracks to take advantage of height channels.
One of my fellow Reference Home Theater writers is looking to update his receiver now as he just bought an OLED and needs HDMI 2.0 support, and the Denon AVR-X6400H is the one I’m recommending to him. I highly recommend the Denon AVR-X6400H for anyone that has a home theater with height channels and wants to avoid the hassle and expense of running separate amplifiers for them. Never did I feel I was lacking in power, and I always fully enjoyed my time with it.
Easy setup, great sound, plenty of inputs and streaming support for almost anyone.
Web setup isn't working quite yet, Audyssey LFC wasn't effective in use.
The Denon AVR-X6400H packs everything you need for a top-end home theater into a single box. You can power, and optimize, a 7.2.4 channel system without any external amplifiers. If you want a Dolby Atmos/DTS:X system that sounds great without needing to run external amplifiers, the X6400H does the job easily while sounding fantastic.