Denon AVR-X3700H AVR Review

[Chromatischism]

I ran REW with Audyssey EQ and without (DEQ turned off). Those two settings are considerably different on my Denon 4700 with the F328Be in stereo. In the chart below the green line shows how Audyssey reduced the built-in bass boost of the F328 and elevated the treble significantly starting at 1.8khz. The reduction of room modes in Audyssey can be beneficial so the EQ below 200Hz makes sense to me. Even though most will probably go back in and use bass boost to get the bass levels back after Audyssey does its thing.

That's not a "built in bass boost" from the F328's. That is your room.

 

[amper42]

I agree that it tends to make neutral speakers brighter, however I don't agree that it "trims the bass". That is not my experience at all and that includes lots of listening and measurements over many years. The only way you get there is if you turned off Dynamic EQ, which defeats the design and target of the bass region.

Denon DEQ and the various RLO settings offer an additional layer of bass boost EQ on Denon receivers.
It's another way to further impact the speakers original design curve. It does NOT help with room modes but it can give your speakers a bass boost especially in frequencies below 80Hz with RLO 15 having the least impact and RLO 0 setting offering the largest boost. I found a speakers with substantial low frequency capability don't typically need DEQ, in fact it may induce unwanted room vibrations. But if you are suffering from lack of bass especially at low volume levels it's another option.

However, if you have great speakers the listener can decide if they love Denon's various built-in EQ options or the natural sound of the speaker. If you don't critically listen to both you'll never know the difference. AND if you can take the speaker off the Denon AVR and listen to it with a high quality DAC it will offer another performance point to decide between. EQ is not always your friend - especially with Audyssey and DEQ totally changing the FR of your high quality speakers. In addition, the signal processing of the AVR adds distortion. You don't really notice it until you bypass the AVR completely and use a high quality DAC like the ADI-2 instead. It's a different level of clarity compared to my Denon 4700.

 

[Chromatischism]

However, if you have great speakers the listener can decide if they love Denon's various built-in EQ options or the natural sound of the speaker. If you don't critically listen to both you'll never know the difference.

I have great speakers and I do plenty of critical listening with them. I know very well the differences.

The flaw in your reasoning is that you will not hear the "natural sound of the speaker" (or subwoofer) in the bass region in your room. Further, if you insist that flattening the response with Audyssey yet not using Dynamic EQ, then complaining that it "cuts the bass", you are missing the design goal of the system. Those two features are meant to go hand in hand to get you to a target, which is variable based on volume level. It's not perfect, but it's the closest any AVR gets from my experience. I hope they further refine it with the upcoming software.

 

[Chromatischism]

AND if you can take the speaker off the Denon AVR and listen to it with a high quality DAC it will offer another performance point to decide between. EQ is not always your friend - especially with Audyssey and DEQ totally changing the FR of your high quality speakers. In addition, the signal processing of the AVR adds distortion. You don't really notice it until you bypass the AVR completely and use a high quality DAC like the ADI-2 instead. It's a different level of clarity compared to my Denon 4700.

External DACs don't add anything you don't already get from a Denon AVR, meanwhile you most often lose bass management which ends up being a losing proposition if you use subs.

As to your claims of "signal processing distortion", that will need to be proven to be worth anything on this site. And that includes whether any such distortion is audible over the immense benefits of room EQ.

 

[Acerun]

You can try the reference curve that offers two roll offs. You may like the 2nd one (not the default one) as it has a steeper roll off. Or ypu can limit the eq range to below 2K.

Thanks for the idea, peng. I tried the 2k cutoff and it's my favorite so far. Much appreciated.

 

[amper42]

As to your claims of "signal processing distortion", that will need to be proven to be worth anything on this site. And that includes whether any such distortion is audible over the immense benefits of room EQ.

If you look at @amirm measurements of Denon 4700 you see a drop in SINAD DAC performance by 22dB just from the strain of using the internal Denon amp (75.885dB). By placing the AVR in pre-out mode and using an external amp the DAC performance improves to 97.287dB. That's a sizable measurable difference that the RME ADI-2 does not confront with it's 114.63dB SINAD DAC performance.

The Denon 4700 review uses Pure Direct Mode with amps off for testing to achieve the best possible measurements but we all know that's NOT the normal operation by most users of this AVR. In all categories the DAC, internal amps can't compete with the SINAD results of the Purifi/RME ADI-2 DAC combination. I would love to see the Denon AVRs measured in their normal operating mode with Audyssey and DEQ engaged and internal amps on with an HDMI source. If the unit measured above 70dB SINAD with digital processing engaged I would be very surprised.

There is no way the Denon 3700/4700 AVR can offer as clean a sound as today's quality DACs but it offers a home theatre experience that our stereo DAC's lack. So, if I need 7.2.4 or 5.1.2 or any other combination I settle for the performance of the Denon 4700 AVR. But I don't kid myself into believing it's an equal in stereo performance to the RME ADI-2 DAC FS or other high performing DAC/amp combinations.

Denon AVR-X4700 AVR Review (Updated)

This is a second review of the Denon AVR-X4700 AVR. It was kindly purchased by a member and drop shipped to me. It costs US $1,700 from Amazon including free shipping. I will explain the reason for the revision in a bit. For now, I will cut and paste some of the information from the first...

www.audiosciencereview.com

RME ADI-2 FS Version 2 DAC and Headphone Amp Review

This is a review and detailed measurements of the updated version 2 of the RME ADI-2 FS DAC and headphone amplifier. It was kindly sent to me by the company. The cost us US $1,149. The ADI-2 looks very nice in black with a bright, super responsive display (doesn't come out as well in the...

www.audiosciencereview.com

 

[Chromatischism]

If you look at @amirm measurements of Denon 4700 you see a drop in SINAD DAC performance by 22dB just from the strain of using the internal Denon amp (75.885dB). By placing the AVR in pre-out mode and using an external amp the DAC performance improves to 97.287dB. That's a sizable measurable difference that the RME ADI-2 does not confront with it's 114.63dB SINAD DAC performance.

But the claim was "signal processing distortion", that being that the FIR equalization is causing distortion. So we aren't talking about amp or DAC performance but the Audyssey algorithms.

 

[Chromatischism]

Even still, I bet even a 70 SINAD with room correction sounds far better than 120 SINAD without.

 

[mauian]

Just did some simple tests. As expected, if I went back to the speaker menu and set the SB, Height/Atmos to none, then when playing an Atmos movie, I could still select the downmix options such as Dolby Digital+Neural:X. Mine is X4400H but if I would think the X3700H would behave the same way. Have you tired it? If that's how it work then I wouldn't consider it "...that channel information is lost.." As Galz said, if you set it (amp assign) to 5.1, then all you would get will be 5.1 and an Atmos, or 7.1 track would be downmixed to 5.1 as well, so I don't see a difference, but I could be wrong.

Thanks, Peng! I had no idea I could select downmix options...haha. I'll take a look tonight. Thanks again.

 

[Roland]

Even still, I bet even a 70 SINAD with room correction sounds far better than 120 SINAD without.

We'll never know, though, will we? One could equally bet that it sounds worse.

 

[Chromatischism]

We'll never know, though, will we? One could equally bet that it sounds worse.

If I were a betting man, I wouldn't bet on those odds.

 

[notabenem]

If you look at @amirm measurements of Denon 4700 you see a drop in SINAD DAC performance by 22dB just from the strain of using the internal Denon amp (75.885dB). By placing the AVR in pre-out mode and using an external amp the DAC performance improves to 97.287dB. That's a sizable measurable difference that the RME ADI-2 does not confront with it's 114.63dB SINAD DAC performance.

Reading the first post: Peak performance at 1.1V - 101dB SINAD, and it's still excellent up to 1.4V, AMPS on. That 'abysmal' -75dB was at 2V.
I wonder at what listening levels do we reach 1.4V? Because If I never reach that during regular operation, then -100dB is more than enough for me!

 

[peng]

Reading the first post: Peak performance at 1.1V - 101dB SINAD, and it's still excellent up to 1.4V, AMPS on. That 'abysmal' -75dB was at 2V.
I wonder at what listening levels do we reach 1.4V? Because If I never reach that during regular operation, then -100dB is more than enough for me!

You can estimate it if you know your speaker's sensitivity, nominal impedance, and distances.
For example, assume sensitivity of 88 dB/2.83V/m, 8 ohm nominal impedance, 11 ft from the left or right speakers, at 1.4 Vrms, the power output should be about 195 W average, or 390 W peak, SPL (assume that's what you meant by listening levels.) would be about 100 dB average, or 103 dB peak. Keep in mind at 1.4 V, the internal amps of the AVR-X3700H should be well into clipping already, and that's why the preamp/DAC's SINAD would start to drop, reaching about 75 dB (still as good as the AV7705 though lol..) as at that point the internal amps would be heavily clipping.

Note that the preamp/DAC isn't really "clipping" as such at 1.4 V or even 2.0 V output, just that its SINAD would drop from the "contamination" of the internal power amps that are actually clipping, heavily.

Edit: the above estimated numbers (SPL) are based on 1 speaker only, and no room gain assumed.

 

[notabenem]

@peng Would you please be so kind and also drop the formulas used? I want to recalculate that to 2x 4ohm speakers (JBL A130, 86dB sensitivity) and me sitting ~4m distance from the speakers with AMP volume mostly below 70dB to see if I am in the clipping region or not.

 

[peng]

@peng Would you please be so kind and also drop the formulas used? I want to recalculate that to 2x 4ohm speakers (JBL A130, 86dB sensitivity) and me sitting ~4m distance from the speakers with AMP volume mostly below 70dB to see if I am in the clipping region or not.

The easy first step could be to simply use an online calculator such as the following:

Peak SPL Calculator

Crown Audio - Professional Power Amplifiers

www.crownaudio.com

For the speaker's sensitivity, 86 dB/2.83V/m is equivalent to 83 dB/Watt/m, that's because Power = (V^2)/R, so for a 4 ohm load, the power output into 4 ohm will be double that into an 8 ohm load.

Now use the calculator in the first link above, if you input 83 dB for sensitivity, 4 meters for distance, that is about 13 ft, and 2 speakers as you wish, you will see that 105 W (the rated output of the AVR-X3700H) you will get about 94.3 dB, assuming no room gain. 105 W average means the peak will be 2X105 W = 210 W so the peak SPL will be 94.3+3 = 97.3 dB.

To the 2nd part of your question, that is, with the AVR volume at 70 dB, to see if you are in the clipping region or not it gets a little more complicated:

First of all, you will have to know the trim level setting if you did run auto setup/Audyssey, because it will affect the overall "volume". Let's assume the trim levels for all channels are 0, then from Amir's measurements, the Pre out voltage would be about 2 V at volume setting of 82.5.

We know the gain of the Denon's internal amps is about 29 dB, to calculate the Vo (power amp output) from Vi (preamp output = Power amp input), you can use the formula:

Vo = Vin X V gain factor,
V gain factor = 10^( Voltage gain in dB/20) = 10^(29/20) = 28.18, so Vo = 2 X 28.18 = 56.36 V
Power output, Po = (Vo^2)/R = 56.36 X 56.36/4 = 822 W for a 4 ohm resistor load.

Remember that would be at volume 82.2. If you turn it down to 70, you can calculate the corresponding output voltage using the formula below:

Po = 822 X 10^(70-82.2)/10 = 46.24 W into 4 ohms or 23.12 W into 8 ohms

You can see that at volume setting 70 you won't be clipping because Amir's tests were based on the input signal at 0 dBFS, whereas for movies, if you go by THX standard, 0 dBFS already assume a 20 dB peak for movies that are recorded to -20 dBFS average.

Note: The results obviously depends on the input voltage that in turn would depend on the recording levels of the media contents, the calculations shown above are based on using digital input signal at the so called dBFS level.

dBFS - Wikipedia

en.wikipedia.org

Are you getting the "THX Reference Level" in the listening position? Do we really need such an output level in our home-theater rooms?

I've seen several threads on Internet forums about measuring THX Reference Level on our domestic audio equipment from home. A very good article about the THX Reference Level would be http://www.acousticfrontiers.com/2013314thx-reference-level/. A very good read would be...

www.audiosciencereview.com

Keep in mind, every time you turn the volume up by 3 dB you will be doubling the output power so if you set the volume to say 77, or -3 on the relative scale, you will be clipping for sure during peaks.

I am not good in presentation unless I get to spend some hours preparing, if you want to see all the related formula online, the website linked below is probably one of the best:

dB calculator for amplification gain and damping (loss) factor of an audio amplifier calculation decibel dB ratio - sengpielaudio Sengpiel Berlin

Calculator damping loss and dB amplification factor gain decibel amplifier audio engineering microphone recordings calculation ratio - sengpielaudio Eberhard Sengpiel

www.sengpielaudio.com

 

[notabenem]

Thanks @peng for the links and explanation.

So if I understood all this, then at Volume 70, I need 46W per channel, which translates to Vin=SQRT(46.24W*4Ohm)/Vgain = ~0.5V
Volume up to 79 => 46.24*2^3 => 1.36Vin
That seems to be still before the clipping of 1.4 with AMPS on. Happy camper? I think I am.

Is there going to be any change if i turn on 2 more speakers (surround channels)?

 

[peng]

Thanks @peng for the links and explanation.

So if I understood all this, then at Volume 70, I need 46W per channel, which translates to Vin=SQRT(46.24W*4Ohm)/Vgain = ~0.5V
Volume up to 79 => 46.24*2^3 => 1.36Vin
That seems to be still before the clipping of 1.4 with AMPS on. Happy camper? I think I am.

Is there going to be any change if i turn on the 2 more speakers (surround channels)?

If you turn it up to 79 you will risk overloading the amp. I think 70 t0 73 should be safe if it is well ventilated, but you should still use an extern fan to help cool the unit.

More speakers wont matter for the pre out but will obviously put more load on the power supply. Again, get a couple of fans if you want the avr to last and go easy on the volume.

 

[notabenem]

If you turn it up to 79 you will risk overloading the amp. I think 70 t0 73 should be safe if it is well ventilated, but you should still use an extern fan to help cool the unit.

More speakers wont matter for the pre out but will obviously put more load on the power supply. Again, get a couple of fans if you want the avr to last and go easy on the volume.

That surprises me. Obviously must something I am not aware of. My previous marantz AVR served me 12 years and still as good as new, yet it was operating also around 40C. Now I do have a sub as well. Why do we think higher temps (40-50) will damage the unit?

 

[peng]

That surprises me. Obviously must something I am not aware of. My previous marantz AVR served me 12 years and still as good as new, yet it was operating also around 40C. Now I do have a sub as well. Why do we think higher temps (40-50) will damage the unit?

I think you are referring to the temperature on top of the unit. Even 50 deg C on top is not going to cause immediate damage but I would longevity would suffer as the inside temperature at some locations such as the output device and their heatsinks could be much higher.

Regarding your point about having volume at 79, that just seems too high for me especially for 4 ohm speakers. You are not missing anything though, I guess I am just being overly cautious. The fact is, depending on the media contents, assuming you are using HDMI, the average voltage, current and power when watching say a THX Star War movies would be well within the limits, but during certain peaks, voltage will clip and current may approach or exceed the output devices limits.

For example, if your 4 ohm nominal speakers have dips to 2.5 ohm or lower, at 40 V output 40 V/2.5 = 16 A, that's just rms values. Then there is also the potential issues of the extra heat dissipation in the output devices if there are high phase angles that coincide with the impedance dips.

But again, you are right, there may not be any issues as it really depends a lot on the contents, among other things. It's not just the volume setting, but also the input signal level too. If the signal is high enough, even volume 70 could be a problem. Blue ray movies would likely follow standards but not all contents do. For multiple channel use, if the content has a lot of simultaneous peaks in more than 2 or 3 channel, that again could overload the power supply, albeit not on continuous basis.

I have never had my volume at more than -10, or 70 and I use external amps. So okay, if you are not concern, but I would not go higher than 73 if I had the 3700.

 

[Ekkoville]

Gentlemen, I hope you can help me understand the impedance compatibility. I wish to buy a Denon AVR-X4700H and use it as a pre-amp with my Rotel RMB-1095 Amp. The Rotel manual says the following on Input Impedance/Sensitivity: 33k Ohms/1.5 volt (unbalanced).
Will this Denon pair correctly with this Rotel Amp? Thanks for your help.

Great question, I have the same amp and am wondering the same thing!