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Denon AVR-X4700H 2020 AVR Review

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amirm

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This is a review and detailed measurements of the newly announced Denon AVR-X4700H 9.2 channel AVR. It was kindly purchased by a member and drop shipped to me for testing. It costs US $1,700 on Amazon including Prime shipping.

NOTE: post publication of this review, Denon Engineering kindly contacted me to analyze the results and together we discovered an operational issue that has now been resolved, resulting in much better measured performance for this AVR. An updated set of measurements and new thread for discussion of the same is here: https://www.audiosciencereview.com/forum/index.php?threads/denon-avr-x4700-avr-review-updated.14493/ As such, please ignore the test results in this thread.

There is nothing to write home about as far as industrial design as it looks like many other AVRs:

Denon AVR-X4700H 8K Home Theater Receiver AVR Dolby Atmos Surround Review 2020.jpg

We have the typical back connections:
Denon AVR-X4700H 8K Home Theater Receiver AVR Dolby Atmos Surround Review Back Panel Inputs Ou...jpg

In use, the unit was robust, never shutting down in 2-channel testing. However, the right side of the unit where I think the front left and right channels exist, got very hot. It was so hot that it was uncomfortable to touch the top of the case even though it is 1 inch or more removed from the heatsink. There is a fan under them but it did not come on. I worry about long term reliability of this unit so I suggest assisted cooling if you are going to use it anywhere near full power.

For testing, I turned off the eco mode and operated the unit with just two large front right and left speakers. For some of the tests, I selected the 11 channel mode which allowed me to reassign them to "external amp" which provides better performance in that configuration. Alas, there is no way to do the same for the center channel which is a miss. In this regard, there is no improvement over the last generation AVRs. Why Denon doesn't recognize that the center channel in movies carries most of the content and hence requires strong amplification is beyond me.

Testing these AVRs is a bit of a nightmare as features that should be orthogonal (independent) of each other, aren't as you will see in testing. To avoid literally hundreds of combination of modes, I weave my way through the unit switching configurations back and forth as necessary to get through it. So please stay with me and pay attention to the notations on the graphs and review on what configuration is being tested.

There is a nice diagnostic mode to show you the HDMI signal being received and transmitted to the TV. Sadly, it only shows video settings and not audio! What a shame. Why not state the bit depth and sampling rate of the audio as well?

NOTE: Denon engineering has been in contact with me and has shared their measurements with me. Their data does NOT show a regression from AVR-X3600H. We are investigating the differences between our setups hoping to get more insight as to why we are getting different results. Some progress has been made but more work is needed. Appreciate everyone's patience until we get to the bottom of this.

AVR DAC Measurements
The heart of the audio subsystem in an AVR or processor is conversion of digital audio samples to analog. So we always start there by tapping the "pre-out" from the back of the unit instead of using speakers (to eliminate the effect of amplifiers). Let's start with HDMI input and leaving the unit as shipped (i.e. front amps connected):

Denon AVR-X4700H 8K Home Theater Receiver AVR Dolby Atmos Surround HDMI Audio Measurements.png


We see the typical high harmonic distortion due to internal amplifier stressing the power supply causing the DAC to underperform. Fortunately in this amplifier we can turn them off for the fronts as mentioned and this gets us an improvement:

Denon AVR-X4700H 8K Home Theater Receiver AVR Dolby Atmos Surround HDMI External Left and Righ...png


Notice how much cleaner the FFT spectrum is. Actually, that is a lie because it looks clean because the noise floor is quite a bit higher than it should be. This is why, despite distortions being below -100 dB (which is good), our SINAD which is a combination of noise and distortion is still quite lackluster:

Best Home Theater AVR Processor Review 2020.png


And among all products tested with DACs in them:

Best stereo surround DAC 2020 review.png


Here is where things get strange. If I switch to Toslink optical input, noise level goes down and performance increase substantially:

Denon AVR-X4700H 8K Home Theater Receiver AVR Dolby Atmos Surround CD Toslink Optical Audio Me...png


Clearly the HDMI subsystem is spitting noise into the sensitive DAC circuits, polluting them. Even now though, the 4700H underpeforms the AVR-X3600H I reviewed recently which clocked at SINAD of 99 dB. And that was with HDMI which is the most common use case for an AVR.

We can see the effect of HDMI high noise floor in our dynamic range test:

Denon AVR-X4700H 8K Home Theater Receiver AVR Dolby Atmos Surround HDMI External Left and Righ...png


This is truly shameful seeing how much worse it is than the 3600H. We can't even clear 16 bits of dynamic range for CD. 40 Years after introduction of the format, it seems we have to struggle just to get to that level of performance!

High noise floor plagues 4700H's performance in IMD distortion test relative to level: (ignore the label on right: red should be Denon AVR-X4700H)

Denon AVR-X4700H 8K Home Theater Receiver AVR Dolby Atmos Surround HDMI External Left and Righ...png


A little phone dongle connected to a noisy computer does better than this AVR! And this is with all the wiz bang modes on such as Pure Direct which even turns off the front panel. It made no difference anyway as it is not turning off the true sources of the noise. It aims to appease your imagination rather than reality of noise in the unit.

We can see the contrast between HDMI and Toslink when we run our jitter test:

Denon AVR-X4700H 8K Home Theater Receiver AVR Dolby Atmos Surround HDMI External Left and Righ...png


One note about this test: the AVR went crazy when I told it to play this standard test signal (J-test). It produced a totally garbage output with level shooting way up to around 3.5 volt. It would only produce the right output if I turned the volume way down. Clearly the signal processing inside the unit is getting confused, overflowing or whatever with J-test input. This indicates to me no jitter test was ever run or this problem would have been caught and fixed.

High noise floor masks low level signals naturally in 24-bit PCM audio samples:

Denon AVR-X4700H 8K Home Theater Receiver AVR Dolby Atmos Surround HDMI External Left and Righ...png


As a way of reference, this is Denon's last year AVR-X3600H on the same test:

index.php


There is a common processing library these companies are using that causes multi-tone test to also be reproduced horribly:

Denon AVR-X4700H 8K Home Theater Receiver AVR Dolby Atmos Surround HDMI External Left and Righ...png


Notice how the peaks don't line up either indicating level errors versus frequency. This industry seemingly knows nothing about proper unit/corner case testing.

Filter response is the typical, rather slow filter but now with high noise floor:

Denon AVR-X4700H 8K Home Theater Receiver AVR Dolby Atmos Surround HDMI External Left and Righ...png


THD+N versus frequency shows very high levels due to high noise across wide spectrum:

Denon AVR-X4700H 8K Home Theater Receiver AVR Dolby Atmos Surround HDMI External Left and Righ...png


Running the same sweep but relative to level with the amps on we get:

Denon AVR-X4700H 8K Home Theater Receiver AVR Dolby Atmos Surround HDMI THD+N vs Level Amps On...png


As you see, even at lower output levels, you get rather poor performance struggling to get above SINAD of just 90 dB.

Shutting off the amps helps as reported earlier but not a whole lot:

Denon AVR-X4700H 8K Home Theater Receiver AVR Dolby Atmos Surround HDMI External Left and Righ...png


Analog Pre-amp Measurements
I always test to see if analog input works better or as good as digital in AVR as that allows me to then compare the amplifier in them to output amps. Here is that performance:

Denon AVR-X4700H 8K Home Theater Receiver AVR Dolby Atmos Surround CD Analog In Audio Measurem...png


We see that performance is a couple of dBs better than Toslink indicating the ultimate limit of the analog buffer/volume control/gain stage. Not a great news but does allow us to run the amplifier tests with analog input, telling us its best case performance.

AVR Amplifier Measurements
As usual, we start with our dashboard of 1 kHz tone, 5 watts output into 4 ohm load:

Denon AVR-X4700H 8K Home Theater Receiver AVR Dolby Atmos Surround CD Analog In Amplifier Audi...png


This is actually above average for an amplifier:

Best stereo amplifier reviewed 2020.png


And among AVRs:
Best Home Theater Amplifier in AVR Review 2020.png


Notice that it is sitting very close to the 3600H indicating the same design with none of the screw ups that exist in the digital/HDMI subsystem.

Frequency response is identical in all CD modes which surprised me:
Denon AVR-X4700H 8K Home Theater Receiver AVR Dolby Atmos Surround CD Analog In Amplifier Freq...png


Maybe it never digitizes this input? Anyway, it is good to see such wide bandwidth and dead flat response in audible band.

Crosstalk is not that great but fortunately that is not a huge audible thing:
Denon AVR-X4700H 8K Home Theater Receiver AVR Dolby Atmos Surround CD Analog In Amplifier Cros...png


Dynamic range is nearly as good as 3600H:

Denon AVR-X4700H 8K Home Theater Receiver AVR Dolby Atmos Surround CD Analog In Amplifier SNR ...png


We have a bit more power than 3600H:
Denon AVR-X4700H 8K Home Theater Receiver AVR Dolby Atmos Surround CD Analog In Amplifier Powe...png


Denon AVR-X4700H 8K Home Theater Receiver AVR Dolby Atmos Surround CD Analog In Amplifier Powe...png


And into 8 ohm:

Denon AVR-X4700H 8K Home Theater Receiver AVR Dolby Atmos Surround CD Analog In Amplifier Powe...png


Finally testing to see frequency dependency on power and distortion+noise:
Denon AVR-X4700H 8K Home Theater Receiver AVR Dolby Atmos Surround CD Analog In Amplifier 4 oh...png


Performance at lower power levels and frequencies is not as good as 3600H due to high noise level. Luckily our hearing threshold is pretty high at low frequencies so this is more of an engineering issue than audibility.

Conclusions
If you don't have any goals, you are likely to miss them! -- Amir when reviewing Denon AVR-X4700H

Someone asked me in the review thread of Denon AVR-X3600H if the good performance of that AVR was by design. My answer was that it had equal odds of being an accident seeing how these companies have no design specifications/metrics. That sadly seems to be true. Modification of that architecture with new digital subsystem has sharply raised the noise level of the AVR-X4700H, reducing its performance across the board. Clearly there was no noise specifications for the unit to meet.

We could argue average person can't hear distortion but noise is easy to hear (and measure). It is a shame the company has not tried even modestly to keep that under control.

Instead of chasing the next logo ("8K" here), I wish AV companies would go back to putting engineering design targets in place and produce a proper, performant product. Don't these engineers want to be proud of their work? I mean, we are not holding them to high standards -- just meet or beat your own, last generation product!

Part of this blame goes to a press/blogging industry that pays little to no attention to the audio performance of these products. A frequency response test and and a power curve or two is all they seem to do. So naturally when Denon wanted to announce the new products, they ran to these outlets. Maybe we don't matter. But maybe we do with over a million visitors per month coming here. I sure hope parent company of these products (Sound United) honors the tradition of these companies to build high performance audio products and set some standards of performance.

Now, there is some good news here in the form of amplification. If the heat doesn't kill it, the amps at least in 2-channel mode provide a lot of power. And Audyssey Room EQ if used correctly, will add a lot of subjective goodness.

Anyway, I am so unhappy with the state of product development in these companies and despite some good traits, I cannot recommend the Denon AVR-X4700H.

My deepest thanks for the member that stepped up to get this unit for us to test this early in its sale cycle.

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As always, questions, comments, recommendations, etc. are welcome.

I am hungry. Ran through every fast food app but none has $2 sandwiches anymore! Can you all donate more money so I can afford full price fast food? https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 
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GXAlan

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Great review. So sad for Denon. This would suggest that DDSC-HD and AL32 may be detrimental. (loss of 5 dB comparing x3600 hdmi versus x4700 optical)

Or alternatively, the new 8K HDMI receiver May not be as good as the mature 4K HDMI receiver.
 

SDX-LV

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What a monumental disappointment in Denon! I was literally planning to buy X3700, but now... I need to think and wait for something better to come along. Maybe MiniDSP produces something? anyone?
 

RichB

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These products either lack performance requirements or don't hold engineering to them.

I was considering replacing an older Onkyo used as a preamp with the X3700H. That is now on-hold.

Thanks for another great review.

- Rich
 

GXAlan

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@amirm
Let me ask our now mutual friend about getting in a X3700H or a X8500H (which would let us see the effects of the 8K HDMI chip versus the DDSC-HD/AL32/Auro CPU). Do you have either in the queue?
 
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pozz

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I wonder what level of an analyzer they are using, they state analog out with 1kHz @2Vrms is 0.008%, yet you measured down below 0.002% with Toslink.
Maybe they just a use a wider bandwidth.
 

BsdKurt

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The 2020 Denon's have a full pre-amp mode where all internal amplifiers are disconnected. It would be interesting to see if that helps with the DAC performance with HDMI input.
 
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amirm

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@amirm
Let me ask our now mutual friend about getting in a X3700H or a X8500H (which would let us see the effects of the 8K HDMI chip versus the DDSC-HD/AL32/Auro CPU). Do you have either in the queue?
I do not.
 

capt.s

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Someone asked me in the review thread of Denon AVR-X3600H if the good performance of that AVR was by design. My answer was that it had equal odds of being an accident seeing how these companies have no design specifications/metrics.
I think you're right Amir. I hope so actually as I have a 2017 X4400H I run in 11.2 mode with the amps disconnected and up until now I assumed it likely had the same performance as the X3600H you tested. How a higher priced newer model can perform worse than the X3600H is straight up embarrassing for Sound United! Who knows what the X4400H measures as it seems up to a lucky chance how they turn out.
 

Deeluik

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Hmmm I thought that clock jitter reducer which is not present in the x3600h would make a difference... so it seems it does but not in a positive way :rolleyes:
 
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amirm

amirm

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Can you test the headphone amp? Someone recently asked if they should use their AVR or go out and buy a HP amp/DAC, and I don’t know how they perform so I just said “Hey, if it sounds fine, don’t worry”.
Usually they have very high impedance as they simply tap into the amplifier with an inline resistor. That makes them anemic on high impedance headphones and changes their frequency response.
 
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