Denon AVR-X6700H Home Theater AVR Review

[hmt]

Hi Amir,

love the work you are doing here, so many thanks.

I have one question, that I had asked in another review, but wasn’t has answered (I believe), so I dare to ask it gain.

Currently, I am using a Denon 6500, and are about to switch to the 6700 for the amp disconnect feature, as I am (since recently) using a dedicated 2CH amp for the mains.

Now, it was said that the Denons have a gain of 29dB. My external amp has a gain (according to the spec) of 30,5 +-0,5dB. I am using a separate preamp/amp for 2channel listening, and connect the Denon via a home theatre input pass thru when watching movies (lucky me the manual says that it has sensitivity of 1.3V, so I guess it reaches max. power at that voltage, which is below the range where things get worse with amps connected (which I cannot disconnect anyway with the 6500).

So my question is: What exactly does it mean that the AVR has a lower gain than my external amp. From the spec, I have a deviation of between 1 (30,5-0,5) and 2 dB (30,5+0,5).

My best guess is that at reference level (measured and set through Audyssey) all is fine, but when I turn down the volume, the relative volume changes between the speakers connected to the external and internal amps respectively. How I understand gain would mean that my L/R, since the external amp has a higher gain, would play (significantly?) lower in relation to speakers connected to the internal amps.

How significant is this really becoming at let’s say -5db and -10db reference level.
(I have the luxury to actually being able to view a movie in this range, revLevel to -10dB...)

Many thanks,
Christoph

No, the difference does not change. If your external amp had a gain of 31 db and a sensitivity of 1.2V it would always be 2 db louder. In your case I would expect only a small difference.

 

[Timbo2]

Fair point, it may depend on if I were the head of the marketing, finance or engineering department..

I realize this is tongue in cheek, but you realize that marketing, engineering and finance are all necessary to bring everyone the products that they want at prices they are willing to pay.

Give engineering unconstrained time and resources and they can come up with amazing products. Give marketing unlimited features and low price and they can sell the heck out of the product. Finance are the poor folk that track and allocate the scarce resources.

The C-Suite is responsible for the balancing act between these parts of the company.. Also, they are responsible for the culture and how an organization responds to its customers when there are issues and problems.

 

[DrewMcG]

Since you seem to be referring to my post, it was a response to the comments earlier on why can’t AVR manufacturers build AVRs with as good a performance as stereo amp and preferably at or less than the price of a stereo amp (and throw the rest of the AVR in for free) and if they are not doing that, is it because they are deliberately exploiting the customers?

On that point I agree with you its an unreasonable expectation. I was more confused by raising "diminishing returns" in the context of the x6700h deficiency Amir's testing revealed. Not a diminishing return issue whatsoever.

 

[peng]

Hi Amir,

love the work you are doing here, so many thanks.

I have one question, that I had asked in another review, but wasn’t has answered (I believe), so I dare to ask it gain.

Currently, I am using a Denon 6500, and are about to switch to the 6700 for the amp disconnect feature, as I am (since recently) using a dedicated 2CH amp for the mains.

Now, it was said that the Denons have a gain of 29dB. My external amp has a gain (according to the spec) of 30,5 +-0,5dB. I am using a separate preamp/amp for 2channel listening, and connect the Denon via a home theatre input pass thru when watching movies (lucky me the manual says that it has sensitivity of 1.3V, so I guess it reaches max. power at that voltage, which is below the range where things get worse with amps connected (which I cannot disconnect anyway with the 6500).

So my question is: What exactly does it mean that the AVR has a lower gain than my external amp. From the spec, I have a deviation of between 1 (30,5-0,5) and 2 dB (30,5+0,5).

My best guess is that at reference level (measured and set through Audyssey) all is fine, but when I turn down the volume, the relative volume changes between the speakers connected to the external and internal amps respectively. How I understand gain would mean that my L/R, since the external amp has a higher gain, would play (significantly?) lower in relation to speakers connected to the internal amps.

How significant is this really becoming at let’s say -5db and -10db reference level.
(I have the luxury to actually being able to view a movie in this range, revLevel to -10dB...)

Many thanks,
Christoph

It doesn't matter where you set the volume, if you run auto setup/Audyssey, it would level match all channels whether the speakers are connected to the internal amps or external amps, it will all be adjusted so they will sound equally loud at any volume level.

If you don't run auto setup for whatever reasons, then you should use your own spl (sound pressure level) meter and use the AVR's internally generated tone to adjust the level of each channel so that they will all sound equally loud.

 

[Chriz]

It doesn't matter where you set the volume, if you run auto setup/Audyssey, it would level match all channels whether the speakers are connected to the internal amps or external amps, it will all be adjusted so they will sound equally loud at any volume level.

If you don't run auto setup for whatever reasons, then you should use your own spl (sound pressure level) meter and use the AVR's internally generated tone to adjust the level of each channel so that they will all sound equally loud.

Thanks Peng and hmt....

 

[Anterantz]

Okay I thought you meant measurements of the power amp output, so it is about pre-out, thank you for the clarification, but what is midio?

Anyway, take a look again of the graph below and it may answer your question whatever it is.
The dark blue and red lines were measured SINAD with the internal amps disconnected.
The dark and light green lines were measured SINAD with the internal amps connected.

Since Amir has indicated this graph will now be standard for AVRs/AVPs, so you should be able to see one for the 8500 in a couple of weeks, I guess.

The 8500 has a better DAC IC but it has the same volume control IC that appears to be the bottom neck for pre-out SINAD so my bet is on it measured similarly well/or bad as the X3600H and X4700H. I doubt it would have suffered from the substituted cap like the 6700 had because there were no C-19 or anything else at the time that caused shortages. It may do a little better in noise as it evidently has better power supplies, general layout but then the even better layout/shielding scheme of the Marantz AV8805 that is blood related, did not do as good as the little AVR-X3600H or the X4700H, so I would be prepared to get surprised and disappointed, have to wait and see..




View attachment 75228

hello peng sorry my english I am Spanish and I communicate with you via google translator!

I do not expect much from the measurements of the 8500h I am the first to think that the brands deceive us as they want ... surely it has a sinad equal to or less than the 3600h and the truth does not take away my sleep!

It is my 4 avr having marantz sr7010 / 7013 arcam avr 390 and 8500h ... being the latter the one that has sounded the best in my room.



I refuse to think that a 3600h sounds better than an 8500h or an arcam avr850 ... the final performance that an avr provides is not just its dac there is a lot of technology, research inside a box that turns out to be the final sound.


if it were all so easy ... we would all buy a mid / low range model and add a stage and voila!

regards

 

[AudioJester]

... we would all buy a mid / low range model and add a stage and voila!

Nailed it!

 

[jomark911]

Denon execs must be wetting their bedsheets ...

Is that so?

 

[amirm]

This is a serious issue, and I bet the person who signed off on the substitution (albeit evidently temporary)believed users would not be able to hear the difference between the batch with the substitute cap and the batch that has the originally specified cap in the BOM. That is, the difference between 87 and 97 dB SINAD at 2 V, and about the same 10 dB difference in the other tests, a little less in imd,, about 5-8 dB difference from what I could see.

I don't think they knew the replacement capacitor degraded performance until I ran my tests and they verified the same. It was a straight part substitution which would be common for a capacitor (being a generic part). There is something seriously out of spec with the cap to cause this problem though.

My hope is that from here on companies run the same tests I do so that they catch the problems themselves, rather than me.

 

[Vasr]

My hope is that from here on companies run the same tests I do so that they catch the problems themselves, rather than me.

Wouldn't this particular problem with the "bad" cap be caught in the measurement ANY OF THEM do for harmonic distortion (or S/N or whichever they normally do that would cover this, I am not an expert on these measurements)? Unless, they never ran their usual test suite on a unit with the substitute part which would be a QC issue rather than deciding which tests to run. Or they did measure it, knew the degradation and had decided it was acceptable. They just took some time to formulate the response in the latter case.

The down-mixing problem in the 4700 was an edge case from a specific configuration which understandably may not have been part of their normal test suite (it isn't for you either since you didn't do that test on this unit). So they would need to run it.

Is there a special measurement you had to do here to expose this problem rather than a standard test any of them would/should do to arrive at their publish spec or to judge QC acceptance?

 

[amirm]

Wouldn't this particular problem with the "bad" cap be caught in the measurement ANY OF THEM do for harmonic distortion (or S/N or whichever they normally do that would cover this, I am not an expert on these measurements)?

Good point. Just about any audio analyzer would be able to measure it.

 

[amirm]

Is there a special measurement you had to do here to expose this problem rather than a standard test any of them would/should do to arrive at their publish spec or to judge QC acceptance?

Per above, there is nothing special here. Just a simple THD+N measurement. Hook up two cables, press a button and you see the degraded numbers.

 

[theory]

Or they did measure it, knew the degradation and had decided it was acceptable. They just took some time to formulate the response in the latter case.

I wouldn’t know either but I’m pretty sure if I had to guess it was tested with the replacement caps but was probably deemed within their acceptable range. All of us here are comparing it to the X3600H which is our standard. But we have no clue what their benchmark standard is or if they even have one. I am curious how well another x3600 or any of these would measure, not sure how tight their tolaerances are.

 

[Vasr]

I wouldn’t know either but I’m pretty sure if I had to guess it was tested with the replacement caps but was probably deemed within their acceptable range. All of us here are comparing it to the X3600H which is our standard. But we have no clue what their benchmark standard is or if they even have one. I am curious how well another x3600 or any of these would measure, not sure how tight their tolaerances are.

Agree. Nothing was "needed to be done" if it wasn't for this gadfly called Amir who gives them a PR black eye by making the measurements public so they cannot hide the fact that a newer and/or higher end unit measures worse even if inaudible.

You have a valid point that without knowing the tolerances of QC acceptability at Denon when component substitutions happen over time whether that X3600h you rush to buy now will have the same superlative performance as measured for that one or will be way down that list at 10db less cleaner. This applies to all things measured here and ranking them with 1 dB resolution.

 

[bigguyca]

Agree. Nothing was "needed to be done" if it wasn't for this gadfly called Amir who gives them a PR black eye by making the measurements public so they cannot hide the fact that a newer and/or higher end unit measures worse even if inaudible.

You have a valid point that without knowing the tolerances of QC acceptability at Denon when component substitutions happen over time whether that X3600h you rush to buy now will have the same superlative performance as measured for that one or will be way down that list at 10db less cleaner. This applies to all things measured here and ranking them with 1 dB resolution.

Please provide valid experimental evidence that these differences in measurements between Denon units are inaudible. That sounds like a pure opinion.

 

[Vasr]

Please provide valid experimental evidence that these differences in measurements between Denon units are inaudible. That sounds like a pure opinion.

 

[bigguyca]

- Omitted -

The 8500 has a better DAC IC but it has the same volume control IC that appears to be the bottom neck for pre-out SINAD so my bet is on it measured similarly well/or bad as the X3600H and X4700H. I doubt it would have suffered from the substituted cap like the 6700 had because there were no C-19 or anything else at the time that caused shortages. It may do a little better in noise as it evidently has better power supplies, general layout but then the even better layout/shielding scheme of the Marantz AV8805 that is blood related, did not do as good as the little AVR-X3600H or the X4700H, so I would be prepared to get surprised and disappointed, have to wait and see..

- Omitted -

Agreed with your concept, but would add; the X8500H will also have the same mediocre IC opamp in the filter circuitry that follows the DAC IC, and the same NJR CMOS switches to go along with the NJR volume control. The medium and upper level models have a lot of the same parts.

It appears that the use of one more 8-channel volume control IC would eliminate the need for the switches with perhaps a 6dB improvement in THD performance. A few stereo RCA inputs might have to go.

C-19 makes a handy scapegoat. Ship the units in the 2nd quarter to make numbers. Blame one-time recall costs as a special item in a following quarter and blame it on C-19.

A manufacturer would have tested the unit with the different part, and actually would have fully characterized the unit. AVR's are a complex product.

I still wonder if there are software issues as well. The ultimate attenuation level of the reconstruction filter seems hard to blame on a capacitor. This is especially true when, as I remember, a software fix improved a similar measurement of an Emotiva unit as well as other measurements.

A related/unrelated question: Is there an engineer on the payroll of Sound United (SU) in the U.S. who understands the D/M products at the schematic/component/software design level. A chief engineer sort of person. It seems all technical questions to Europe or back to Japan. It isn't clear that Sound United in San Diego County (Vista/) is involved in these technical questions or understands them. Many of these problems may come as a surprise to SU, but that is hardly an excuse. SU may not want to pay for the fulltime resource or for AP type equipment. Remember SU is owned by a private equity firm and is a miniscule part of that firm.

 

[amirm]

All of us here are comparing it to the X3600H which is our standard. But we have no clue what their benchmark standard is or if they even have one. I am curious how well another x3600 or any of these would measure, not sure how tight their tolaerances are.

Denon is supposed to send me a 3600H if they can ever find one. We also get another shot with 3700 which should have a similar circuit topology.

 

[theory]

Denon is supposed to send me a 3600H if they can ever find one. We also get another shot with 3700 which should have a similar circuit topology.

Looks like some vendors are still getting shipments of X3600H but I would think the X3700H should be very similar circuit wise.

 

[man10]

Denon is supposed to send me a 3600H if they can ever find one. We also get another shot with 3700 which should have a similar circuit topology.

Amirm, thanks for your incredible work! Do you have a forecast for the timing of your 3700 review?