Pioneer VSX-LX505 AVR Review

[MbphotoX]

The primary design flaw I am talking about, is not having some form of front panel notification, if it goes into protect mode...

Right now the only way to identify that it is in protect mode, is via the web interface (or lab test gear).

As far as I know, this "protect mode" hasn't been triggered by anyone using the device as intended, within manufacturer specification, etc.


If you had a real-life scenario where you did draw the insane amounts of power that Amir did in his ludicrous stress test, and the receiver DID go into "limp mode"..
Are you gonna tell me that you wouldn't notice that without the receiver telling you so?

After all, we're talking about a decrease in output voltage of nearly 9 dB PER SPEAKER! (dropping from 140W per channel down to 20W per channel.. that's halving the power nearly 3 times (140 : 2 = 70 : 2 = 35 : 2 = 17.5W) and everytime you half the power, output drops by 3dB..)

If you cannot hear the volume of your system getting CUT IN HALF (because a decrease in output by 10dB is perceived as "half as loud", and having multiple speakers getting 8+ dB quieter will definitely be an overall SPL reduction of 10dB), then that's clearly on you and not the manufacturer..


Again, the relays switching to the lower voltage rail is NOT the same as what Amir described as the "limp mode" that the Receiver goes into when stressed beyond its capabilities..
The voltage rail switch does not require a power cycle and reverses as soon as the power is needed to reach higher SPL. (when you turn up the volume again)



It's time to stop whining about an issue that's not an issue at all.

 

[kyuu]

As far as I know, this "protect mode" hasn't been triggered by anyone using the device as intended, within manufacturer specification, etc.


If you had a real-life scenario where you did draw the insane amounts of power that Amir did in his ludicrous stress test, and the receiver DID go into "limp mode"..

Ludicrous? Gimme a break. Why do other AVRs handle his test without triggering an undisclosed, stealth limp mode? Hmm.

Are you gonna tell me that you wouldn't notice that without the receiver telling you so?

Yes, it's quite likely many people wouldn't notice. Their dynamic peaks when listening at decently loud volumes would probably be clipped, depending on the specifics of someone's setup, but that might be difficult for many people to detect.

If you cannot hear the volume of your system getting CUT IN HALF (because a decrease in output by 10dB is perceived as "half as loud", and having multiple speakers getting 8+ dB quieter will definitely be an overall SPL reduction of 10dB), then that's clearly on you and not the manufacturer..

No, it's on the manufacturer not to engage a mode that severely limits the output of the amp section to well below the rated specifications, particularly without any indication to the end user that this mode has been triggered and without any documentation as to how to clear it.

It's time to stop whining about an issue that's not an issue at all.

It'd be nice if people defending Voxx over their lousy engineering would stop whining about people not liking said lousy engineering.

As I've said before, individuals can make their own value judgements and decide what this issue means to them. It's totally legitimate to say that the low sale price (MSRP is not competitive IMO) and other features are bigger concerns. It's not legitimate to pretend that this issue is anything but the result of sloppy engineering, or that it's somehow wrong to expect better from an expensive electronic component, particularly when other brands in the category do not have this issue.

 

[himey]

stop whining about people not liking said lousy engineering.

Your whining is equally annoying.

 

[kyuu]

Your whining is equally annoying.

Extremely useful contribution. Thank you.

 

[ryanmh1]

It'd be nice if people defending Voxx over their lousy engineering would stop whining about people not liking said lousy engineering.

Unless you are an amplifier designer experienced in protection circuitry in consumer products, let's not call this "lousy engineering" unless it can demonstrably occur somewhere outside of a test bench. Many "audiophile" products are designed with inadequate protection circuitry merely to avoid problems on a test bench or to provide mysterious almost immeasurable sonic benefits. That's lousy engineering.

Note the comment in the review of the VSX-LX303 waaaay back in 2019, when all this seems to have kicked off here: "I plan to hook it up to our living room TV system and listen. Maybe in real use the thermal cut-out doesn't occur. If so, I might keep it." I do not see where any follow-up on that was ever done. All the testing has ever shown is that the amplifiers have a protection circuit and a handful of conditions which engage it. None of them have ever demonstrated an actual technical problem, period. Given that Onkyo has sold millions of these things, it is highly likely they have set the time constants in the comparator with more than adequate margin for dynamic loading conditions. What the circuit does not deal with is high, constant "static" loading, which for the product category should occur only under a fault condition, imminent failure, or on a bench test.

Now, if someone hooks this receiver up to a pair of reasonable speakers that costs less than $2500 and actually manages to trip this without putting the speakers under obvious audible stress, I'll eat every word I've said on this subject. If you don't like the protection circuit, fine. Don't buy the thing. But until you understand how it works and whether it actually is improperly designed, or trips during actual use under dynamic conditions, stop griping about "lousy engineering". You have zero evidence of that, just like everyone else. All you know is one condition that will actuate it under static conditions on a bench.

 

[dlaloum]

As far as I know, this "protect mode" hasn't been triggered by anyone using the device as intended, within manufacturer specification, etc.


If you had a real-life scenario where you did draw the insane amounts of power that Amir did in his ludicrous stress test, and the receiver DID go into "limp mode"..
Are you gonna tell me that you wouldn't notice that without the receiver telling you so?

After all, we're talking about a decrease in output voltage of nearly 9 dB PER SPEAKER! (dropping from 140W per channel down to 20W per channel.. that's halving the power nearly 3 times (140 : 2 = 70 : 2 = 35 : 2 = 17.5W) and everytime you half the power, output drops by 3dB..)

If you cannot hear the volume of your system getting CUT IN HALF (because a decrease in output by 10dB is perceived as "half as loud", and having multiple speakers getting 8+ dB quieter will definitely be an overall SPL reduction of 10dB), then that's clearly on you and not the manufacturer..


Again, the relays switching to the lower voltage rail is NOT the same as what Amir described as the "limp mode" that the Receiver goes into when stressed beyond its capabilities..
The voltage rail switch does not require a power cycle and reverses as soon as the power is needed to reach higher SPL. (when you turn up the volume again)



It's time to stop whining about an issue that's not an issue at all.

I agree with you ( as I have said repeatedly) - but...

The "limp mode" still has between 20W and 40W - for most normal household purposes, that covers all needs!

(back in the day, the recommended power for high fidelity sound in a relatively small room was 25W )

With my 86db sensitivity speakers - 20W stereo provides more than 95db....

My normal listening levels are 75db - so I have a full 20db for peaks (well beyond the dynamic range of 99% of recordings!)

So yes - most users, in most use cases, would be completely unaware that the AVR was running in protect mode.

Also if you check the tests AmirM did, it was not "insane amounts of power" it was 5W continuous into a 4ohm load.

But yes there have been no reports of this happening "in the field" ... and 5W continuous stereo, is a continuous level of 89db through my speakers - I don't ever do that, it is way (!) too loud. Which is why it probably has never been encountered in real life.

 

[EWL5]

I agree with you ( as I have said repeatedly) - but...

The "limp mode" still has between 20W and 40W - for most normal household purposes, that covers all needs!

(back in the day, the recommended power for high fidelity sound in a relatively small room was 25W )

With my 86db sensitivity speakers - 20W stereo provides more than 95db....

My normal listening levels are 75db - so I have a full 20db for peaks (well beyond the dynamic range of 99% of recordings!)

So yes - most users, in most use cases, would be completely unaware that the AVR was running in protect mode.

Also if you check the tests AmirM did, it was not "insane amounts of power" it was 5W continuous into a 4ohm load.

But yes there have been no reports of this happening "in the field" ... and 5W continuous stereo, is a continuous level of 89db through my speakers - I don't ever do that, it is way (!) too loud. Which is why it probably has never been encountered in real life.

Additionally, why would the Onkyo RZ70 behave differently for the "audiophile" segment (according to Audioholics confirmed bench test)? If this was a conscious decision to make it consistent across the product line, then the RZ70/805/DRX8.4 would have the same "limp mode" as the RZ50/505/DRX5.4, etc!

 

[ban25]

Additionally, why would the Onkyo RZ70 behave differently for the "audiophile" segment (according to Audioholics confirmed bench test)? If this was a conscious decision to make it consistent across the product line, then the RZ70/805/DRX8.4 would have the same "limp mode" as the RZ50/505/DRX5.4, etc!

The RZ50 is a 2021 model. The RZ70 is a 2023 model and it is a completely new architecture.

 

[EWL5]

The RZ50 is a 2021 model. The RZ70 is a 2023 model and it is a completely new architecture.

True. However, the much nicer audiophile grade ESS DACs tells me the RZ70/805 was always going to cater to a different crowd than the RZ50/505!

 

[dlaloum]

Additionally, why would the Onkyo RZ70 behave differently for the "audiophile" segment (according to Audioholics confirmed bench test)? If this was a conscious decision to make it consistent across the product line, then the RZ70/805/DRX8.4 would have the same "limp mode" as the RZ50/505/DRX5.4, etc!

I'm betting it does have the same protect mode, but due to its much higher power and current capabilities, the trigger point is also set higher - and none of the standard lab tests have triggered it.

 

[dlaloum]

The RZ50 is a 2021 model. The RZ70 is a 2023 model and it is a completely new architecture.

In release timeline terms yes, but in development and hardware terms - they were both on the certification lists as having been tested and certified for DTS PlayFi and WiFi at the same time in 2021 (along with another unreleased model series... the RZ90).

So the hardware had already been finalised, and sent off for certification...

When it was released, was a manufacturing and marketing decision.

 

[ban25]

I'm betting it does have the same protect mode, but due to its much higher power and current capabilities, the trigger point is also set higher - and none of the standard lab tests have triggered it.

Sorry, but that makes no sense.

Let's review what Audioholics said about the new protection mechanism:

Onkyo TX-RZ70 11.2CH AV Receiver Review

The Onkyo TX-RZ70 11.2CH AV receiver boasts 140 watts/ch, 8K HDMI inputs, Auro 3D, FREE Dirac Live and the BEST bench test results we’ve seen in its price class. Is this the best AVR at under $3k?

www.audioholics.com

I’m pleased to see Onkyo addressed the issue we discovered in prior models tested (including Integra) that would go into a low power mode after fault protection occurred, which could only be reset by unplugging the unit from the wall rather than a simple power toggle. Instead, if a fault condition occurs with the TX-RZ70, the unit checks the amplifier channels one by one when turned back on. It takes a couple of minutes, but it is probably a good measure to help troubleshoot fault conditions beyond overdriving in a bench test scenario.

Given the unit shuts down, reboots, and enters an amplifier check routine when driven into protection, what would be the point of also having some secret limp mode that only activates *beyond* the point where the unit shuts down? Likewise, if there was a secret limp mode that activates before that point, we would see it in the bench test results.

 

[dlaloum]

Sorry, but that makes no sense.

Let's review what Audioholics said about the new protection mechanism:

Onkyo TX-RZ70 11.2CH AV Receiver Review

The Onkyo TX-RZ70 11.2CH AV receiver boasts 140 watts/ch, 8K HDMI inputs, Auro 3D, FREE Dirac Live and the BEST bench test results we’ve seen in its price class. Is this the best AVR at under $3k?

www.audioholics.com

Given the unit shuts down, reboots, and enters an amplifier check routine when driven into protection, what would be the point of also having some secret limp mode that only activates *beyond* the point where the unit shuts down? Likewise, if there was a secret limp mode that activates before that point, we would see it in the bench test results.

There is consistent confusion around the Onkyo family's protection modes... at least on the RZ50 and down, there is a "short circuit" type (protect from releasing the smoke) protection mode - which places the AVR into a complete shutdown.

The RZ70 equivalent, is more sophisticated, and appears to be what is described in the Audioholics review. (my interpretation)

Then there is a different mode, that appears designed to keep the AVR from overdriving the power supply and amps through high current requirements - this is the one that was triggered by AmirM's test of 5W continuous into 4ohm (not triggered by 5W continous into 8 ohm!). - this is the lower power "nanny" mode - the mode that can be identified on the web interface as "protect"

Given the far higher capacity of the RZ70 (and siblings) power supply, as well as amp circuits and heatsinks, one assumes that any protection mode of the type used on the RZ50, would be set with its trigger point, at a level where the power supply or amps circuits would start to be stressed.... I don't know what that level would be, but looking at the PSU and the heatsinks, it would logically be substantially higher (maybe double the current).

The self test protection described for the RZ70 in the Audioholics review, was not identified as having triggered/set the protect identifier on the web interface.... so it appears that there are two different protect modes on the RZ70 too...

It would be nice to have a service manual so we could confirm what these really do, rather than trying to deduce things from the limited testing and the interface.

 

[popej]

this is the one that was triggered by AmirM's test of 5W continuous into 4ohm

Precisely, this was triggered after SNR test at full power and was repeated during a test with 44W continuous. The later probably reveals the real parameters of protection trigger.

 

[EWL5]

Then there is a different mode, that appears designed to keep the AVR from overdriving the power supply and amps through high current requirements - this is the one that was triggered by AmirM's test of 5W continuous into 4ohm (not triggered by 5W continous into 8 ohm!). - this is the lower power "nanny" mode - the mode that can be identified on the web interface as "protect"

Back in the day, we were trained only to sell AVRs that were "high current" to low impedance speaker customers. I guess this disqualifies the 505/RZ50 (and its siblings) as "high current design"!

 

[peng]

It would be nice to have a service manual so we could confirm what these really do, rather than trying to deduce things from the limited testing and the interface.

In the service manual of the 2017 model, RZ820, you can see that it detects voltage (DC), current, and thermal but it provides no details of how the protective schemes work. Since it does detects current, it could then in theory offer overcurrent protection that is time based, and/or short circuit, ie instantaneous overcurrent, or both. Thermal, could be temperature and time based, using heat sensors, or again, might also be based on current and time though it likely is temperature sensor (on heat sinks), and probably also time based. That's 2017, the 2022-23 models may have more sophisticated designs though I think that is unlikely.

 

[dlaloum]

Back in the day, we were trained only to sell AVRs that were "high current" to low impedance speaker customers. I guess this disqualifies the 505/RZ50 (and its siblings) as "high current design"!

Yes - they are definitely NOT high current designs!!! - The RZ70 and siblings is a very different beast, and is indeed a high current design.

 

[RoedeBaer]

As far as I know, this "protect mode" hasn't been triggered by anyone using the device as intended, within manufacturer specification, etc.


If you had a real-life scenario where you did draw the insane amounts of power that Amir did in his ludicrous stress test, and the receiver DID go into "limp mode"..
Are you gonna tell me that you wouldn't notice that without the receiver telling you so?

I've had the LX 505 for a couple of weeks, but sent it back in the end because of mainly two reasons:

1. It sounded too harsh in the higher mids for my taste. At least on my speakers.

2. Playing music with higher volume levels the music became more and more less dynamic the higher the volume plus the AVR seemed to reduce the volume by itself. It was not possible to break through a certain loudness level even when pushed the AVRs volume up to 0 dB. This didn't only affect the built in amps but also the pre out levels. My main speakers are active and yet they wouldn't play at high volumes.

I encountered this behaviour mainly when listening to music, because when this happend vieweing films I was never sure if the lesser dynamic came from the Pioneer or from the movie's mix.

My old AVR is a Marantz SR6007 from 2013, so it is quite old by now and also far less powerful than the pioneer. But still it plays much more dynamic and powerful with my speaker setup.

I wasn't sure about the Pioneer's behaviour, but reading this test's conclusion seems to deliver a reasonable explanation.

 

[Drunkinho]

It sounded too harsh in the higher mids for my taste. At least on my speakers.

What speakers you have?

 

[RoedeBaer]

What speakers you have?

I have the Piega Premium 701 Wireless/Active

My old Marantz SR6007 sounds way smoother. Almost too smooth again, that's why I'm looking for something new right now.