Denon AVR-X4700 AVR Review (Updated)

[KMO]

Just to revise my last post - one thing I didn't take into account was that subwoofers are likely to be higher sensitivity than normal speakers, and you will get back some or all of the necessary level difference there, rather than in amplifier gain.

Normal speakers are often in the 85-90dB range. Subwoofers are generally 90dB or higher.

The Dynaudio Sub RCC mentioned above is 92dB. So the combination of a 36dB power amp with the higher sensitivity would provide the required overall +15dB level increase over typical 87dB main speakers with a 26dB power amp.

 

[ZgSTar]

The subwoofer preout on an AVR is typically 15dB down on other channels, to provide extra headroom for LFE and bass redirection. This can be adjusted somewhat with the level trims, but even at +12dB trim - the highest adjustment - it may not be as high as the other channels.

The subwoofer amplifier is expected to have at least 10dB more gain than the amplifiers on other channels. If you're using a standard amp like a Purifi 1ET400A to drive a passive subwoofer (why?) it probably won't have enough gain. You would want about +44dB to match the internal +29dB main channel amps, but could maybe get away with a bit less. A typical 26dB power amp would be nowhere near enough.

To be clear, when I say "15dB down", I mean for a given target output level. A -20dBFS tone on a main channel would be 85dB SPL. When redirected to the subwoofer, it's equivalent to -30dBFS on LFE, and then there's another 5dB or so fudge.


I'm not sure they have enough power - 500W or more is more typical for a subwoofer. Although if you're only doing music, not films with LFE, then maybe you're fine?

I looked up the Audio Control RS500 and RS1000, which seem to be suggested amps for the DynAudio sub, and their manual says they have 36dB gain - a tad on the low side for the Denon's RCA output, but workable.

Thank you KMO. This is very helpful. I am driving the subs with a purify because I have it and only while I am deciding what to get. Rs500 and rs1000 can drive two subs but from one output and I wanted to keep it simpler and use Audissey to adjust the two subs. I am now leaning towards something icepower 1200 based which should be both powerful enough and cost effective. Your indication on the needed level of gain comes very handy. I owe you.
May I ask you what would you but as an amplifier for the subwoofers if your were me?

 

[KMO]

May I ask you what would you but as an amplifier for the subwoofers if your were me?

I've never done anything other than active subwoofers where the manufacturer's already put an amp in, so not really an expert.

Currently using a single KEF KF92, which has two 500W class D amplifiers in it, one for each driver (and DSP control meaning it can manage the power to get that extension down to 11Hz safely).

You don't really need a super "hi-fi" amplifier for a sub - being at the left-hand end of Amir's SINAD chart isn't really going to buy you anything. I'd primarily worry about gain, auto-wake functionality, and being well-wired and -earthed enough to not pick up mains noise at high gain.

I can see ICEpower-derived modules are popular, for example MiniDSP's amp+DSP backplate.

If I had to guess, that one seems to have selected the ICEpower 250ASX2 because when put into bridged mono mode it's got the sort of high gain you'd want for a sub - 34.4dB. An ICEpower 1200AS doesn't do more than 25.8dB.

 

[HarmonicTHD]

My 2 cents….

The x4700/3700 in pre-amp mode puts out 2V RMS on its RCAs (at ca 97dB THD+N). This it puts out in Direct Mode with the volume knob set to -6dB as I just confirmed over the weekend with both my voltmeter and my osci using a 1kHz sine signal at 0dBFS.

If you use passive subs a power amp with a sensitivity of 26dB turn the 2V RMS into ((2x20))squared / 8) 200W output power. Assuming a weak (worst case) sub sensitivity of 85dB/1W/m gives you ca 100dBSPL at 8ft listening position.

Given the above rough calc one can optimize for their listening preferences. For example you could decide to only operate the X4700 up to its sweet spot of 1.1VRMS out (ca 101dB THD+N). So if you have a very clean power amp you might decide to increase gain of the power amp provided the manufacturer gives you that option). Or you decide for usually better noise performance to go with lower output and max SPL level. Is it audible - doubtful but if the amp can do it it is for free so to speak.

All this of course is no problem for the usual and well engineered active subs which allow to adjust the gain. (I use a Neumann KH750 on my x3700 with plenty of oomph for my room size and listening preferences).

 

[ZgSTar]

My 2 cents….

The x4700/3700 in pre-amp mode puts out 2V RMS on its RCAs (at ca 97dB THD+N). This it puts out in Direct Mode with the volume knob set to -6dB as I just confirmed over the weekend with both my voltmeter and my osci using a 1kHz sine signal at 0dBFS.

If you use passive subs a power amp with a sensitivity of 26dB turn the 2V RMS into ((2x20))squared / 8) 200W output power. Assuming a weak (worst case) sub sensitivity of 85dB/1W/m gives you ca 100dBSPL at 8ft listening position.

Given the above rough calc one can optimize for their listening preferences. For example you could decide to only operate the X4700 up to its sweet spot of 1.1VRMS out (ca 101dB THD+N). So if you have a very clean power amp you might decide to increase gain of the power amp provided the manufacturer gives you that option). Or you decide for usually better noise performance to go with lower output and max SPL level. Is it audible - doubtful but if the amp can do it it is for free so to speak.

All this of course is no problem for the usual and well engineered active subs which allow to adjust the gain. (I use a Neumann KH750 on my x3700 with plenty of oomph for my room size and listening preferences).

Thank you HarmonicTHD, this is very helpful too and much more than 2c of value!

The specifications of the SUB RCC are 92db and it is power rated at 160W continuous with a 400W at peak. This makes me lean now towards the ICEpower 250ASX2 perhaps two to in bridged mode. Looking at the Sabaj a8 it seems like a good choice with full power at 280mv when the volume knob is at max. I am not sure one would be enough but definitely two in a bridged setup? I see a lot of people using those little babies to power passive subwoofers. The good thing is that they sell on Amazon here so I can return them if they don't deliver what I need.

On the other side, I have a desire to always go pre-mode (I now switch it on when listening to music as I only have L+R+sub1+sub2 on external amps) and have asked Rouge audio for a quote and they advised using ICEpower 1200 with a buffer (STUDIO N6) for the subwoofers. I would then go Hypex for all other channels, 252 for the satellites, and 502 for L+R.

 

[KMO]

The x4700/3700 in pre-amp mode puts out 2V RMS on its RCAs (at ca 97dB THD+N). This it puts out in Direct Mode with the volume knob set to -6dB as I just confirmed over the weekend with both my voltmeter and my osci using a 1kHz sine signal at 0dBFS.

But that would have been on a non-subwoofer channel, right? (Given the 1kHz.) The gain structure is quite different for the sub channel. I'd expect you to see maybe 1V RMS on the RCA with a 0dBFS LFE signal - much less with a 0dBFS redirected main channel bass signal. You'd need bass management summing those to get up to 2V RMS.

 

[HarmonicTHD]

Thank you HarmonicTHD, this is very helpful too and much more than 2c of value!

The specifications of the SUB RCC are 92db and it is power rated at 160W continuous with a 400W at peak. This makes me lean now towards the ICEpower 250ASX2 perhaps two to in bridged mode. Looking at the Sabaj a8 it seems like a good choice with full power at 280mv when the volume knob is at max. I am not sure one would be enough but definitely two in a bridged setup? I see a lot of people using those little babies to power passive subwoofers. The good thing is that they sell on Amazon here so I can return them if they don't deliver what I need.

On the other side, I have a desire to always go pre-mode (I now switch it on when listening to music as I only have L+R+sub1+sub2 on external amps) and have asked Rouge audio for a quote and they advised using ICEpower 1200 with a buffer (STUDIO N6) for the subwoofers. I would then go Hypex for all other channels, 252 for the satellites, and 502 for L+R.

Got it.

With the 92dB Sub driven at its max continues power rating of 160W you get ca 106dB SPL (ear shattering). So the 1200icepower is pretty much an overkill for this sub and assuming a domestic listing application and the 250 icepower more suited. Also consider that higher gain amps of similar composition usually exhibit a slightly higher noise level (yes again at a non audible level, but if the solution fits both aspects why not).

For the satellites you need much less power, probably even 50 to 100W more than suffices for living room 5.x systems.

I also use my x3700 in preamp only and configured my Neurochrome power amps (Mod686 for LR, Mod268 for satellites) for only 20dB gain. It allows me to drive the x3700 closer to its THD+N sweetspot and still give me the SPL I listen to maximally. (I get „for free“ some ca 3dB lower noise from the power amps to ca 126dB dynamic range - again not audible).

 

[HarmonicTHD]

But that would have been on a non-subwoofer channel, right? (Given the 1kHz.) The gain structure is quite different for the sub channel. I'd expect you to see maybe 1V RMS on the RCA with a 0dBFS LFE signal - much less with a 0dBFS redirected main channel bass signal. You'd need bass management summing those to get up to 2V RMS.

Correct, I measured the non sub outs not the LFE out. Thanks for the clarification …
So assuming a 1VRMS sub out a ca 32dB gain for a power amp would be needed to arrive at the above mentioned 200W out into 8 ohms (hope I didn’t made an error in my math here on the fly).

 

[samstar]

Hi Guys,
I'm new to ASR and have been reading thru a lot of posts recently as I'm in the market for a new AVR. I'm looking at the Denon 4700H but have a question about the 11.2 processing vs 9.2 channel amp.

From what I understand, I can connect an external 2ch amp to the AVR to process 11.2 (I'm looking to set-up 7.1.4 - currently on 7.1)). However, I also believe that the Front L/R are not assignable and so the external 2ch amp cannot be used to drive the fronts - is my understanding correct?
I'd have to use the Denon's internal amps to drive the fronts and assign the external amp to other channels. Ditto if I was to buy a 3ch amp, it could not be used to drive L/C/R? At least not without the internal amps all being switched off and relying solely on external amps for all channels in which case it defeats the purpose of the internal amps !?!
If correct, then the 2ch external amp connecetd to the pre-out is really only good for 2 of the rears or atmos - in which case in a 7.1.4 set-up, which would/should be driven by the external 2ch amp? In either case, 2 of the rears or 2 of the ceilings will be driven by the external and 2 by the internal amps? That's doesn't sound (no pun intended) like a good recipe.

Is my reading correct or am I missing something?

 

[amper42]

Welcome to ASR.
Your thoughts are not correct.
1. You can assign the Fronts to an external amp. You can do that in Amp Assign while configuring a 7.1.4 configuration. Select "Pre-outs" for front to do so.
2. You can also set the Denon 4700 in full "Pre-out mode" and assign the two channel external amp to the fronts that way. The beauty of this is you can save it as a preset and always go back to it for stereo while having a second preset for 7.1.4. Many users like this option.

The full pre-out option of the Denon 4700 is awesome. I use it for 7.2.4 with all external amps. But using it for stereo in another great way to setup the Denon and maximize SINAD performance. The key will be using an amp that reaches 97dB SINAD measurements or better. The chain is only as good as the weakest link.

 

[samstar]

Well that's weird. I remember reading somewhere that Denon specifically stated that the fronts are not assignable (or maybe that was on the 3700H? - now I've confused myself).
At least that's good news. I'm liking that option 2 you mentioned. Sounds perfect for music listening and HT viewing. But what about the sub in 2ch mode?
I assume I can also assign the front 3 L/C/R if I buy a 3 ch ext amp?

 

[amper42]

Well that's weird. I remember reading somewhere that Denon specifically stated that the fronts are not assignable (or maybe that was on the 3700H? - now I've confused myself).
At least that's good news. I'm liking that option 2 you mentioned. Sounds perfect for music listening and HT viewing. But what about the sub in 2ch mode?
I assume I can also assign the front 3 L/C/R if I buy a 3 ch ext amp?

1. Denon 4700 only allows the Fronts to be assigned to pre-out while setting up in 7.1.4 mode.
2. The "Pre-outs" are always live on the Denon 4700. You could connect an amp to the Center pre-out but the internal amp will also be "live" so the sound quality will be impacted by that.
3. Of course, you can get around this limitation by using full pre-out mode in amp assign. In this mode NONE of the internal amps will feed speakers.

You have to determine what's best for you and whether you can notice a difference. When I connected the Monolith 7x200 and used full pre-out mode the sound was crisper to me and the action movies sounded amazingly crystal clear. With the internal Denon amps it didn't offer the same sound to me. Some swear the internal amps are enough. You have to decide what you believe. Sometimes that is hard to do until you have actually tried a quality amp. So making sure you have good return terms makes sense.

 

[Destroid]

^^^ what he said ^^^

Amp assign/disable is one of the better new features on the Denons. (Hopefully the 8500 fully independent assignments trickle down).

I think there is still confusion. You can always use as many external amps as you want via preouts. (I run a 3 ch for the LCR)
Amp assign mode repurposes the internal LR amps to drive a pair of heights (If connected)

Only in pre-out mode are all the internal amps off.

 

[samstar]

1. Denon 4700 only allows the Fronts to be assigned to pre-out while setting up in 7.1.4 mode.
2. The "Pre-outs" are always live on the Denon 4700. You could connect an amp to the Center pre-out but the internal amp will also be "live" so the sound quality will be impacted by that.
3. Of course, you can get around this limitation by using full pre-out mode in amp assign. In this mode NONE of the internal amps will feed speakers.

You have to determine what's best for you and whether you can notice a difference. When I connected the Monolith 7x200 and used full pre-out mode the sound was crisper to me and the action movies sounded amazingly crystal clear. With the internal Denon amps it didn't offer the same sound to me. Some swear the internal amps are enough. You have to decide what you believe. Sometimes that is hard to do until you have actually tried a quality amp. So making sure you have good return terms makes sense.

To be clear, the assignable amps are for the front L/R only?
If the pre-outs are always 'live' doesn't this apply to the front L/R as well as the center?
Or are you saying that with the 'live' front L/R, we can bi-amp?

^^^ what he said ^^^

Amp assign/disable is one of the better new features on the Denons. (Hopefully the 8500 fully independent assignments trickle down).

I think there is still confusion. You can always use as many external amps as you want via preouts. (I run a 3 ch for the LCR)
Amp assign mode repurposes the internal LR amps to drive a pair of heights (If connected)

Only in pre-out mode are all the internal amps off.

Now I am confused. If an external amp can be assigend to the front L/C/R via pre-out, then these 3 inboard amps are disabled. But I thought only 2 channels could be diabled (or all of them for full pre=out)? How many can actually be assigned/diabled then?

 

[amper42]

To be clear, the assignable amps are for the front L/R only?
If the pre-outs are always 'live' doesn't this apply to the front L/R as well as the center?
Or are you saying that with the 'live' front L/R, we can bi-amp?

Now I am confused. If an external amp can be assigend to the front L/C/R via pre-out, then these 3 inboard amps are disabled. But I thought only 2 channels could be diabled (or all of them for full pre=out)? How many can actually be assigned/diabled then?

You may be trying to make this more complicated than it is?
1. The first point you need to decide is if the sound quality with internal amps engaged is different than with a higher quality 97dB SINAD amp connected in full pre-out mode. Measurements indicate the internal amps offer lower SINAD than in full pre-out mode and above 1.4V internal amp performance drops quickly.

2. If #1 above doesn't matter to you then you can use any Denon 4700 pre-out and not be concerned about the internal amp activity. There is no "assign" or "reassign" function. You simply plug the amp into the pre-out you want to use. The pre-outs are always live.

3. If you want to optimize the performance of the Denon 4700 you can use one of the methods discussed above using external amp(s). In this example you have two options. A. Assign fronts to "pre-outs" or B. Disable all internal amps from playing music and use external amps instead.

If you try to superimpose another theory on top of the examples above you will confuse yourself.

 

[Destroid]

Those of us with 10 years with these receivers tend up to use the Denon jargon. Last try, then you need to DYOR.

The 4700/6700 can be run in many ways. Crutchfield has a good breakdown in the details section https://www.crutchfield.com/p_033AVX4700/Denon-AVR-X4700H.html#pane-C

1. Just hook up speakers to all internal amps. Works well with a subwoofer and bookshelf speakers.

2. Use the pre out connections to hook up 2 or more channels of external amplification (Typically LR) Some speakers are using the internal amps.

3. Only use external amplification via the pre out connections.

None of the above requires any special setting and will work with older models.

Newer Denons have special modes that support higher quality by disabling the internal amps. These models have 2 options:
"amp assign" that repurposes the LR internal amp for height2. (Use with option 2 above)
"preamp mode" that disables all the internal amps (Option 3 above)

Only the high end 8500 lets you pick and choose individual amp assignments and if they are on or off.

 

[samstar]

If i hook up an ext amp to the front LCR if the pre-outs are live, does this disable those LCR internal amps?
What's the sound quality like (to those that have done this) compared to te int amps (I know it depends on the amp purchased like a Parasound)?

 

[HarmonicTHD]

If i hook up an ext amp to the front LCR if the pre-outs are live, does this disable those LCR internal amps?
What's the sound quality like (to those that have done this) compared to te int amps (I know it depends on the amp purchased like a Parasound)?

Look at the Sinad measurements on page 1 At best an improvement from about 85dB to about 95dB. Very very unlikely one will hear any difference for music reproduction.

 

[Sonic icons]

Are there any measurements showing how high the preamp output voltage can go before clipping, in "preamp" or "internal amp off" mode? I see the figure showing the pre-outs clip at 1.4 V rms with internal amps on. But this figure stops at 2 V rms, and shows the pre-out signal is still clean (very low distortion) at that voltage.

 

[peng]

I see the figure showing the pre-outs clip at 1.4 V rms with internal amps on.

I posted many times that pre out did not really clip at 1.4 Vrms and I think I know the reason why people keep saying that it did. So just for my curiosity, can you tell me where did you see that it clip at 1.4 V? Would it be from the following graph:

Are there any measurements showing how high the preamp output voltage can go before clipping, in "preamp" or "internal amp off" mode?

Amir did it for the AVR-X6700H, but only in preamp mode. When not in preamp mode, you should be able to get similar output voltage, but at much lower SINAD. The AVR-X4700H likely have basically the same preamp/DAC circuitry and parts (based on the similarity I have seen between the X4500H and X6500H. So I think the X4700H may have basically the same preamp/DAC circuitry and parts as the X6700H too, fewer channels obviously. If so, I would expect the X4700H to do at least 3 V, likely 4 V, before clipping.