Direct, Pure Direct & Stereo with Audyssey by-pass

[tparm]

Like many of you here I am a constant tweaker. Thanks to @amirm and @walt99 I am using an A110 with a Node 2 via coax to Gustard X16 analog to the A110. I've been listening to 2CH via Tidal and NAS in Pure Direct through my LSiM 707s and it is remarkable. I'll spare you all the subjective superlatives to describe what I am hearing, but lets just say it sounds really good.....

Soon I'll be in a much larger dedicated space and I'm thinking I may wish to engage two PB-3000s in sealed mode for some (or all) music. Can I do this without digitizing the signal and therefore making my X16 redundant?

Information I've found on 2CH Stereo Mode set to Large for LR, SW to yes, LFE+Main and Audyssey bypass for LR is pretty vague, and many of you have a much deeper understanding of listening modes and how the processor responds than I, would this arrangement achieve what I am going after? Bass management would be nice without digitizing the playback in the LR channels, but that doesn't seem possible in my brain.

Please advise. Thanks.

 

[Golfx]

I found SVS tech/sales guidance for speaker setup to be spot on for me. They will advise you to set LR to small though. I am curious if you have tried Denon’s HEOS App via wifi straight to your Denon at 24/192. It doesn’t do MQA but does do tidal and amazon music hd.

 

[peng]

Information I've found on 2CH Stereo Mode set to Large for LR, SW to yes, LFE+Main and Audyssey bypass for LR is pretty vague, and many of you have a much deeper understanding of listening modes and how the processor responds than I, would this arrangement achieve what I am going after? Bass management would be nice without digitizing the playback in the LR channels, but that doesn't seem possible in my brain.

Please advise. Thanks.

The only sure ways for the signal to remain analog all the way are:

- Use the 2 channel analog input and direct or pure direct model.
- Use the 7.1 analog inputs.

If you use the 2 channel analog inputs and stereo mode, speakers set to large, leave bass management alone, then if would appear the signal would remain analog too based on Amir's tests. Any deviation from that may result in the signal being digitized again, and to get a definitive answer you would have to get your particular scenario tested by Amir, or contact D+M support for an official answer.

 

[tparm]

I found SVS tech/sales guidance for speaker setup to be spot on for me. They will advise you to set LR to small though. I am curious if you have tried Denon’s HEOS App via wifi straight to your Denon at 24/192. It doesn’t do MQA but does do tidal and amazon music hd.

I agree 100% on LR being set to small in every instance except critical listening to two channel music (in Direct or Pure Direct). I did use HEOS when I had Amazon HD but I got rid of Amazon as the user experience for me was lacking compared to Tidal. I wanted to not like Tidal but ends up its the favorite of the streaming services I've used so far and now because of access to the military discount it is just as affordable as all the others. Then I went down the rabbit hole; the Gustard has a superior DAC (and measurements) to both the Node and A110 but you can't stream directly to it except for wifi; all my gear is running via Ethernet and using the Node 2 s the front end UI and the Gustard as the DAC in D/PD modes has produced excellent results. The Polks go deep and sound very good, but initially I bought the PB-3000s based on their ability to play music in sealed mode with accuracy and very low distortion so it's a bummer to not be able to engage them unless I bypass the Gustard DAC.

Now, this was more important when I owned the X4700, now that I have the A110 I suppose I should listen again in Stereo with fronts set to small, with subs, and see what I think. I haven't done so since I implemented the A110. As I ramble on.....

 

[tparm]

The only sure ways for the signal to remain analog all the way are:

- Use the 2 channel analog input and direct or pure direct model.
- Use the 7.1 analog inputs.

If you use the 2 channel analog inputs and stereo mode, speakers set to large, leave bass management alone, then if would appear the signal would remain analog too based on Amir's tests. Any deviation from that may result in the signal being digitized again, and to get a definitive answer you would have to get your particular scenario tested by Amir, or contact D+M support for an official answer.

Thanks @peng

 

[AdamG]

Like many of you here I am a constant tweaker. Thanks to @amirm and @walt99 I am using an A110 with a Node 2 via coax to Gustard X16 analog to the A110. I've been listening to 2CH via Tidal and NAS in Pure Direct through my LSiM 707s and it is remarkable. I'll spare you all the subjective superlatives to describe what I am hearing, but lets just say it sounds really good.....

Soon I'll be in a much larger dedicated space and I'm thinking I may wish to engage two PB-3000s in sealed mode for some (or all) music. Can I do this without digitizing the signal and therefore making my X16 redundant?

Information I've found on 2CH Stereo Mode set to Large for LR, SW to yes, LFE+Main and Audyssey bypass for LR is pretty vague, and many of you have a much deeper understanding of listening modes and how the processor responds than I, would this arrangement achieve what I am going after? Bass management would be nice without digitizing the playback in the LR channels, but that doesn't seem possible in my brain.

Please advise. Thanks.

Check Setup, Audio, Audyssey, MultEQ XT32, here you should be able to switch from Reference to L/R Bypass, or Flat, and Off. L/R Bypass might work for what you are trying to do. I use L/R Bypass when playing 2 channel music but I want to engage my subs and Audyssey only on the bass,

 

[zuli]

This is my current understanding of the different settings:

| Source                  | Mode                | Front LR set  | Signal        | Front LR output         | Sub output (Bass LFE) | Sub output (Bass LFE + Mains)      |
|-------------------------|---------------------|---------------|---------------|-------------------------|-----------------------|------------------------------------|
| Analog / Digital stereo | Stereo              | Large         | (A/D) DSP D/A | Full                    | NA                    | <LPF xo                            |
| Analog / Digital stereo | Stereo              | Small         | (A/D) DSP D/A | >xo, or Full if sub off | <xo                   | <xo                                |
| Analog                  | Direct, Pure Direct | Large / Small | Analog source | Full                    | NA                    | ? if small: <xo, if large: <LPF xo |
| Digital stereo          | Direct, Pure Direct | Large / Small | D/A           | Full                    | NA                    | ? if small: <xo, if large: <LPF xo |

>xo, <xo means above or below the crossover set

 

[peng]

On my Denon 4700, if 2-Channel mode is setup with full range on the fronts then the subs are turned off. Peng, are you saying using 2-Channel mode with the fronts set in full range while using Direct or Pure Direct is the only way to stay in analog mode with the Denon receiver?

Thank you!

Sort of, before I asked Amir to do the test on Stereo mode (he usually use the CD input) analog input, I always thought direct/pure direct mode, analog input would by pass the ADC/DAC path based on the block diagrams. So I email Denon/Marantz support and they confirm I was correct.

I also challenged Marantz about if that was the case then how come in direct mode I could still select speaker small, set XO and the sub would still work. On that, I don't remember their exact wording in the response but basically they still maintained ADC/DAC would be bypassed in DM/PDM analog inputs. As well, Gene** also mentioned that some bass management would still be available even in such mode/analog input.

Now the following:
1) Amir did the test and clarified that in fact if analog input (again he uses CD input, but I know it is the same for any analog inputs) is used, then even in stereo mode ADC/DAC would be bypassed as long as you set speakers to large, no sub, no bass management.

2) I have used REW to find out what happened to the frequency response if I use analog input and direct mode with the sub on but XO set to whatever. I don't remember the results but can likely find them.

I can find Gene's(reference ** above) remark on the Denon (one of the high end model way back), and my test results (as mentioned in 2) and post them, but if will be later today, have to go out now.

For now, to summarize:

You can bypass the ADC/DAC path in the following combinations:

- Stereo mode, speakers large, no bass management DSP used.
- Direct or Pure Direct mode.

- In the older D+M models (such as my AV8801), in direct mode you cannot have the sub on unless you set bass to LFE+Main.
- In the newer models, 2017 and newer for sure, likely 2016 too, you can have the sub on in direct mode without setting the bass setting to LFE+Main.

 

[tparm]

@peng This is good stuff and the additional info you mentioned, if you can find it, would be helpful. " In the newer models, 2017 and newer for sure, likely 2016 too, you can have the sub on in direct mode without setting the bass setting to LFE+Main." - how so?

"As well, Gene** also mentioned that some bass management would still be available even in such mode/analog input." - Interesting

 

[peng]

@peng This is good stuff and the additional info you mentioned, if you can find it, would be helpful. " In the newer models, 2017 and newer for sure, likely 2016 too, you can have the sub on in direct mode without setting the bass setting to LFE+Main." - how so?

As follow:

Owner's manual page 244-245:

Note that the above applies to both Direct and Stereo modes.

 

[peng]

@peng This is good stuff and the additional info you mentioned, if you can find it, would be helpful. "
"As well, Gene** also mentioned that some bass management would still be available even in such mode/analog input." - Interesting

As I mentioned, it was a high end model from way back, did a search and found it was the AVR-5805.
Denon AVR-5805: Measurements and Analysis: Preamp Section | Audioholics

Denon Advanced AL24 Processing Benefits (according to Denon)​

• Frequency response expansion
• In addition to the bit extension by conventional AL24, the amount of information of music reproduction is expanded by performing interpolation on a real-time axis with original high-speed signal processing technology.
• Real time variable filter
• In order to perform reproduction optimal to high sound quality, Advanced AL24 detects signal changes in real time, where a trigger is generated to change dynamic filtering

​

The light blue trace represents analog output frequency response of the main channels via analog input signal with no bass management applied. The green trace represents the bass management applied with a crossover setting of 80Hz. Notice that no A/D to D/A conversion stage took place to apply bass management as indicated by the lack of brickwall filter response at high frequencies. At first, I didn't understand this until I pinged Denon and they informed me of a completely independent bass management system done in the analog domain to ensure a true analog signal path was maintained. Audiophiles and fanatics can rejoice. Now you can have a true analog bypass with proper bass management (if needed). This is a truly incredible and thoughtful feature.

Note About Pure Direct Mode​

When configuring Pure Direct mode, I recommend setting it to the "Basic" bass management option first so it copies the front channel distances that were established during auto setup. Afterwards, you can select "Custom" if you desire to change the crossover setting or even the distance compensation. Note however that distance compensation in Pure Direct mode and all modes for that matter can be fine tuned to 0.1ft increments if you enable this accuracy in the main speaker distance set-up menus, otherwise it will default to 1ft resolution (the typical limit of most costlier processors).​

I don't know if the AVR-X8500H has something similar to do the basic bass management when in direct mode, when the ADC/DAC and DSP blocks are bypassed. I think it probably does.

Also as mentioned, when I asked Marantz on whether Direct mode would bypass ADC/DAC/DSP, I was told the following:

Hello,

Looking at the Analog Audio Block in the 7705's service manual it appears that an analog input signal while in Direct or Pure Direct mode does bypass the DSP and there's no ADC / DAC at that point. The signal is sent to 2 independent switches, then to the Volume IC and finally to the HDAM module before it goes to the pre-out section.

To purchase any of our service manuals, please see the following link. https://www.service-manual.net/?download=69229-marantz-av7705-service-manual


Thanks,
Marantz NA

When challenge them, if that's case, how come there is still some basic bass management such as selecting speaker small and subwoofer "yes", and "LFE+Main" etc., their response was:

Looking at the end of the Volume IC trace, I do see there's a Tone Control (crossover) which would explain the low frequency output to the sub in Direct Mode.

Thanks,
Marantz NA

Those are responses from Marantz but I remember reading similar stuff from Denon too, but I don't remember if it was from their support, FAQ or something else. Rest assure if this applies to the AV7705, it obviously should apply to the SR7015, AVR-X4400H and later models.

I think that's all I have promised to find for you. If I missed something, let me know and I'll see if I have the information.

Edit: Found the Denon response (note obviously he made a typo, he must have meant Direct or Pure Direct):

Thank you for contacting Denon Support, we value you as a customer and appreciate the opportunity to be of assistance!

Setting the unit to PURE or PURE DIRECT will bypass the internal DAC allowing your source to process the sound.


If you have any further questions please feel free to contact us again.

Thank you for contacting Denon Customer Support. Have a great day!


Warm Regards,

Anthony
Tier II Technical Support Lead
Sound United North America
Denon | Marantz | Polk | HEOS | Definitive Technology

Anyway, Amir's test certainly confirmed D+M's claims for the most part.

 

[tparm]

@peng Above and beyond as always. Thank you.

I can confirm via the Denon app when set up as shown Audyssey is off which leads me to believe this is a true analog path. I have to get back to work and this was a quick and dirty test but by all appearances this proves the points above. I have no idea how bass management is handled however. I may actually turn LR bypass back to off to see if it affects playback in Direct/Pure Direct.

 

[AdamG]

Check Setup, Audio, Audyssey, MultEQ XT32, here you should be able to switch from Reference to L/R Bypass, or Flat, and Off. L/R Bypass might work for what you are trying to do. I use L/R Bypass when playing 2 channel music but I want to engage my subs and Audyssey only on the bass,

OK guess I will say it again. Maybe it was lost in traffic, but this is how to disable Audyssey processing for the front left and right but keep the processing for subs.

 

[peng]

OK guess I will say it again. Maybe it was lost in traffic, but this is how to disable Audyssey processing for the front left and right but keep the processing for subs.

I don't think it got lost in traffic, but if I understand him right, he seems to want to know even with Audyssey set to to L/R bypass, would the signal still get digitized.

 

[tparm]

I don't think it got lost in traffic, but if I understand him right, he seems to want to know even with Audyssey set to to L/R bypass, would the signal still get digitized.

@AdamG247 Peng is is correct in understanding my question.

 

[AdamG]

I don't think it got lost in traffic, but if I understand him right, he seems to want to know even with Audyssey set to to L/R bypass, would the signal still get digitized.

The only way to completely bypass the internal DAC is to use the 7.1 channel analog input on the back. He does not need to use them all. Just the L,R and Sub. I don’t know of any other method. But my original suggestion will produce the minimum amount of processing using eitther “Pure” or “Direct” like you outlined.

 

[peng]

The only way to completely bypass the internal DAC is to use the 7.1 channel analog input on the back. He does not need to use them all. Just the L,R and Sub. I don’t know of any other method. But my original suggestion will produce the minimum amount of processing using eitther “Pure” or “Direct” like you outlined.

Yes, I listed that (7.1 multichannel input) option in my post#3.

But the Direct/Pure Direct mode option I also listed does work too as confirmed by D+M and verified by Amir.

The L/R bypass option may not work. I suspect as soon as you engage Audyssey, even with L/R bypass, the whole signal including L/R will likely be routed through the ADC, but I am not 100% sure about that, someone should ask D+M.

 

[peng]

@peng
I can confirm via the Denon app when set up as shown Audyssey is off which leads me to believe this is a true analog path. I have to get back to work and this was a quick and dirty test but by all appearances this proves the points above. I have no idea how bass management is handled however. I may actually turn LR bypass back to off to see if it affects playback in Direct/Pure Direct.

One question for you about the L/R bypass option, that is, if you configure your speakers for 2.1, would it even give you the option (that is L/R bypass)?

My X4400H won't let me do it, but obviously I can just leave speaker config in 11.1. It is not a problem even for 3.1, just not 2.1. So it really doesn't matter I think, just curious that's all.

 

[tparm]

One question for you about the L/R bypass option, that is, if you configure your speakers for 2.1, would it even give you the option (that is L/R bypass)?

My X4400H won't let me do it, but obviously I can just leave speaker config in 11.1. It is not a problem even for 3.1, just not 2.1. So it really doesn't matter I think, just curious that's all.

Sorry Peng, I have been out of town. I can try to check this out sometime this week.

 

[peng]

@peng - The Denon 4700 lets me setup Stereo with Audyssey L/R bypass. I used that configuration along with "Pre-amp" mode to test the Revel F328Be yesterday.

Thank you, but did you try that with the speakers configured for 2.1 only? My 4400 allows me to use L/R bypass too, but not if the speakers are configured for just 2.1, in other words, if I select all other speakers to none, then I would lose the L/R bypass option, just wonder if the 4700 works the same way.