Yamaha RX-V675 Pure direct vs Straight vs DSP processing

CypZ

Novice Member
Hi guys,

I just bought a Yamaha RX-V675 connected to 5.1 Focal (700 or 800) speakers. Everything is just fine concerning digital stuff I have to do with like DTS/AC3 movies for example. DSPs are just fine and I'm happy with the sound for home cinema purposes.

But I'm also a DJ and for stereo / audiophile listening it become more complicated. I plugged the output of my mixer to the "Audio" input of the receiver, and I can't find the setting that fits my needs ! Here is the status :

1. In Pure direct mode :
+ The sound is very nice
+ There is no delay due to DSP processing
- Only the 2 front speakers works since it a stereo source*

2. In Straight mode :
+ Sound is not to bad
~ There is a small delay but I could live with it
- Only the 2 front speakers works since it a stereo source*

3. In any of the "Digital mode" with DSP :
~ Sound sucks, but I could deal with the 7Ch stereo mode even if not as cool as direct mode
- There is a huge delay which make it very hard / long to beatmatch precisely
+ All speakers works so i have a nice booth/monitor in my ears, but it's useless since it's delayed...

*No subwoofer (sucks) and no rear speakers (since I have them near the place where I mix I wanted to use them as booth/monitor speakers) which sucks even more than no sub.

I have analog gear all long (vinyls --> analog mixer --> analog / stereo output / cables --> Receiver --> Speakers) so I really don't want any DSP to interfere it, especially since this mixer (A&H Xone:92) have an incredible sound I don't want to "digitalize" just because of the receiver...

Is there any way to workaround that ? Maybe using zones (I'm only 5.1 not using 7.1 capabilities of the receiver) ?

I would be very happy with a stereo setup (not surdecoded / enhanced) but displayed on all speakers ! I can't understand why it would necessarly mean DSP !

Thanks for your help / advices !
 

dante01

Distinguished Member
The basic answer is to not use an AV receiver as a slave amp for a DJ mixer. You can't expect the RXV675 to fulfil your requirements because it was never intended to be used in such a manner. The solution is to seperate your DJ exploits from your home cinema and use the appropriate hardware for the task at hand.

Outputting 2 chaannel of audio to 5 or 7 speakers plus a sub isn't exactly the sole purpose of an AV receiver. The reasons for most wanting to power that number of speakers is to fascilitate a surround sound enviroment and not run a nightclub with a dance floor. The receiver you have is not at fault and your requirements are beyondits capabilities. You'd need at least five 2 channel slave amps plus a mono block in order to achieve what you appear to be trying to do?

Can you fascilitate 5.1 from a stereo source without the use of audio processing with an RXV675? No. The nearest you'd get to this is the multi channel stereo mode.
 

PSM1

Distinguished Member
For the receiver to convert a stereo signal to play on all speakers it needs to do some sound processing. This adds a delay and reduces sound quality which is what you are seeing with the DSP modes. Hence if you want all speakers, including the sub, to be used then you have to accept some processing delays.
Ways around this could include setting up zone 2 since this will play form analogue sources but again this may add some delay since the receiver may need to do some processing to sort it out but a test of this will confirm. As for the sub you could set the front speakers to large and if your sub has high level inputs you could wire it in parallel to the fronts so that the sub plays the low end stuff. This may compromise your surround sound system slightly though but trying to do 2 completely different things with the same system is always going to mean a compromise one way or the other. AVRs are designed for AV activities and not mixing/DJing etc. hence there is always going to be a compromise somewhere. If you are serious about mixing etc. then get a dedicated stereo mixing system.
 

CypZ

Novice Member
Hi guys,

Thanks for your answers.

Ways around this could include setting up zone 2 since this will play form analogue sources but again this may add some delay since the receiver may need to do some processing to sort it out but a test of this will confirm. As for the sub you could set the front speakers to large and if your sub has high level inputs you could wire it in parallel to the fronts so that the sub plays the low end stuff. This may compromise your surround sound system slightly though but trying to do 2 completely different things with the same system is always going to mean a compromise one way or the other.
By that you mean it would be possible to setup a second zone (with rear speakers) in pure direct mode ? Or which tests were you talking about ?
 

dante01

Distinguished Member
DSP cannot be applied to the second zone anyway and is only applicable to the main zone, but if you want audio via all the speakers from a stereo source then there's no option to not use audio processing even if using the second stereo zone because the speakers in the main zone would still not all output audio without using DSP. You may even find that the main and the second zone audio is out of sync with one another?
 

PSM1

Distinguished Member
Hi guys,

Thanks for your answers.



By that you mean it would be possible to setup a second zone (with rear speakers) in pure direct mode ? Or which tests were you talking about ?
No you would have a stereo pair in zone 2 and stereo pair in main zone.
 

CypZ

Novice Member
So what would be the solution if I want to keep my speakers and do a 2 x Stereo ? Add another 2x Stereo amplifier slave amp for controlling only rear speakers ? How to switch then between 5.1 and 2x2.0 each time without rewiring the speakers ?
 

dante01

Distinguished Member
Simply engage a stereo mode or press PURE DIRECT. You'd still get stereo output in the second zone and output via the stereo front speakers in the main eoom. You'd not get anything via the sub if dealing with content lacking a discrete LFE channel though if engaging PURE DIRECT and the bass management would only be applicable while using the stereo mode.

Simply wire an additional pair of speakers to the ZONE2/PRESENCE terminals on the receiver and engage the second zone in association with the same source as being used in the main room. The second zone will not output audio sourced via HDMI or S/PDIF.

 
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CypZ

Novice Member
Simply wire an additional pair of speakers to the ZONE2/PRESENCE terminals on the receiver and engage the second zone in association with the same source as being used in the main room. The second zone will not output audio sourced via HDMI or S/PDIF.
Sounds like a good plan (wire speakers as zone2), except I'm gonna re-use the same speakers for rear and second zone (the wires are in the walls so I won't add additional speakers). If this is working as expected I'll check to buy an audio switch or something like that to switch the rear speakers from rear to zone 2 everytime...
 

new29

Novice Member
Hello, I have a Yamaha RX-V375, this model does not have the "Pure Direct Mode" button,

1) have any way to switch to this mode in this receiver ?

2) this mode produces a bypass for the AD conversor (burr brown) ? or only disables the effects and DSPs ?,


thanks for your reply.
 
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dante01

Distinguished Member
Hello, I have a Yamaha RX-V375, this model does not have the "Pure Direct Mode" button,

1) have any way to switch to this mode in this receiver ?

2) this mode produces a bypass for the AD conversor (burr brown) ? or only disables the effects and DSPs ?,


thanks for your reply.

THere is no way to engage PURE DIRECT if using an RXV375, Even if using PURE DIRECT then a receiver would still need to utilise its onboard DACs in order to convert digital audio to analogue prior to being amplified. Use the STRAIGHT mode on the RXV375 if wanting to avoid the DSP modes. STRAIGHT will bypass DSP while still employing bass management and YPAO EQ. PURE DIRECT bypasses bass management and DSP, not the DACs!

When the straight decode mode is enabled, each speaker produces its own channel audio signal (without sound field processing). When you play back 2-channel sources, such as a CD player, stereo sound is heard from the front speakers. When you play back multichannel sources, the unit produces unprocessed multichannel sounds.
 
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new29

Novice Member
Ok, thanks for your reply,
I using the analogue "Audio 1" input via rca in the receiver,

if my input is analogue, and the output is analogue (Speakers),
i have this questions:

1) only for knowledge, in pure direct mode, uses the ADC/DAC even ?, or bypass the conversors directly ?, since i don't have this function i don' t know,

2) straight mode, uses the ADC/DAC even ?, i think that yes, since the "enhancer" mode is enable if i want,

3) ever the sound pass for the conversors even if i use analogue inputs disabling DSPs ?


I found that only in "2 channels stereo" mode and disabling treble/bass, peq, and enhanced mode i have not delay, even if the sound pass for the conversors, this is my experience,
in straight mode the delay is small as say CypZ, but stills,


thanks, regards.
 
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dante01

Distinguished Member
An analogue source would have no reason to use the receiver's DAC. A DAC is only utilised if the source is digital.

The DAC is used if and when required irrespective of the mode the receiver is in. The DAC is fundamental to the receiver when dealing with digital inputs. Without it you'd get no audio output when dealing with digital signal inputs.

Not sure what you are talking about in your 3rd question, but all digital inputs would require the DAC and this has nothing at all to do with DSP. DSP is applied post DAC in instances where the DAC is required.


You may find the following schematic of a typical AV receiver's signal path of interest:



Block Diagram (SBD) - AV Receiver - TI.com
 
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new29

Novice Member
Ok,
thanks for the schematic, i only interested in the knowledge of the signal path from an "analog input signal", only a few questions:

following this schem:
i see that "Analog Line In" pass to the ADC/DAC "Audio Codec" ever, is this correct ?


so, an analog source ever uses ADC/DAC Audio Codec: converted the analog signal to "digital" and then to "analog", there´s no problem at this point,
in the pure direct mode occurs the same, the signal uses the "Audio Code" too, is this correct ?,


at least, the ADC/DAC is no responsible for the delay produced in sound as i see,
the Audio DSP yes,


thanks for your reply, regards.
 

dante01

Distinguished Member
Analog passes through, but obviously isn't processed/converted by the DAC. Some AV receivers do convert the analogue signal to digital for their own proprietary processing, but this is not the case with Yamaha AV receivers. A signal would still need to use the DACs if digital so the DACs are always left enabled irrespective of the mode you are in. The DACs are not an ancillary processing feature, but are primary if the signal is in fact digital. If PURE DIRECT were to turn off the DACs then the receiver would then no longer be able to convert digital signals to analogue and cannot then output the amplified analogue signal to the speakers. Audio codecs are only applicable to signals in the digital domain. You do not need a codec in relation to analogue audio sources and the source is the device performing the conversion using its own decoder. This would still result in PCM digital data if the method of conveyance from the source is digital and this would still go through the DAC for conversion to analogue, but would not require decoding prior to the DAC.


Audio sync issues are usually a result of digital video processing as opposed to audio processing. Audio processing can be executed without any discernible delay and this is not CPU intensive, but video processing is a lot more processor intensive and takes longer. This can result in you getting the audio before the video because the video is being delayed by the processing it undergoes. If you are having issues with audio sync then don't assume it to be the AV receiver at fault because the most common culprit is actually the TV. Many TVs now use processing in relation to refresh rates that can delay the video significantly. Likewise, if using an AV receiver's own video processing then this can cause the video to be delayed in relation to the audio. Turn off all video processing if experiencing audio sync problems.
 
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