What are the major differences between Logitech Z906, 2010 and 2016 revisions?

[Ferather]

Not so sure we are on the same page at the moment. When for example THD is measured on amps, they send a sine wave and compare to see how much of it changed.
You can literally do the same to almost any hardware, even compare before and after a SPDIF transmitter to determine which parts are better.

Amplifier specs will normally show at what Hz or kHz the sine wave was sent, and then the total THD added at that frequency.
The sine wave is not a recording from a microphone, its generated by hardware as far as I know.

So now lets take a CD, with pre-recorded audio, and play it through different AVRs, we will get different results, but not if it where kept as PCM (same as the CD).
As you said a correct bitstream-passthrough scenario will have no loss or change to the audio, but when it hits a traditional DAC and amp, it will.

So now we have audio change at the AVR and audio change at the speaker, which is what I am trying to avoid.

#305: Measuring Total Harmonic Distortion THD using an FFT on an oscilloscope - YouTube
THD and THD+N – Similar, but not the same - Audio Precision (ap.com)

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If you want more data on the older V2 headphones PowerDAC, note, apparently uses SPDIF over USB:

E1DA PowerDAC V2 - (wow/wtf/gtfoh) intro - YouTube
E1DA PowerDAC V2 is a very weird DAC! - YouTube

Some extra data on Windows audio (additional to that mentioned in video 2).

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The price of each speaker will go up by around $30-$60, but the price of the main unit will drop by hundreds maybe more.

 

[Bill_Bright]

Not so sure we are on the same page at the moment.

We definitely are not. You made it clear, you don't care about the recording process. You care about the "final file".

I say one cannot be serious about "high fidelity", "audiophile quality", or "true sound" by only caring about the second part of the process. That is, without knowing the original source "sound", or ensuring the original source sound was recorded properly in the first place.

You want to make sure the singer's voice is not altered during the final stages of amplification. I agree with that 100%.

But without knowing what the singer's voice sounded like when she was singing her song up on that stage or in that studio is just ignoring half the process. If Adele sounds like Ann Wilson, that is NOT true sound - even though Ann Wilson is arguably one of the best singers, ever.

If Adele's voice is all distorted during the recording process, "faithfully" reproducing her voice along with all that distortion during the playback is NOT high fidelity, audiophile quality, or "true" sound.

Sure, when it comes to recorded sounds, we, as the listener have to assume the original sound was meticulously recorded to ensure it is not distorted, has not had extra "information" added, or removed. But that does not mean we should ignore the source either.

FTR, it does not matter the sample rate used during the analog to digital conversion. It can be in the terahertz range. Some information will still be lost from the original analog sound. Whether we can hear that or not, or whether or not new information (distortion) is introduced during that process (and back to analog again) is the issue.

Regardless, you can't start in the middle - which is what you want to do.

Again, I totally agree with you and from the "file" to our ears, there should be no change to the sound (other than amplification/attenuation). I am just saying that is half the aural picture.

Now, I think I've made my point. Time to move on.

 

[Ferather]

Very true, but this is a playback system not a recording system, you are 100% right ofc. But I don't record music, I play it back, so that's why I am about the final file on a playback system.
A CD for example is already mastered, and should already sound how the artist intended on release, the last thing I want to do is undo all that with a bad playback system.

Yes lets move on lol.

 

[Calenhad]

Think I will stay out of the whole amplifier/sound quality debate. There are about as many opinions as there are audio listeners in the world. But I will say this, I enjoy the sound I get from my second gen Z906. I have 2-3 headphones that sound better (imho) from the amplified output on my ZxR. But for surround sound in games and otherwise the Z906 is excellent. I also use the analogue outputs from the ZxR to the Z906. DD/DTS encoding adds enough latency to bother me in high intensity gaming. And it is loud enough that I will prefer to leave the room before there are any audible distortion/clipping.

also noticed the site specs for the optical ports specifies up to 1080p, which can only be for HDMI passthrough (1080p applies to HDMI).

That is one proper typo. Optical ports do not transfer image at all. For reference HDMI is not optical

Would be nice to have a 2023 version, with 6 channel SPDIF PCM support

Well, 6-channel PCM support is not possible via SPDIF. It is bandwidth limited to 2-channel PCM or 6-channel encoded audio (Dolby/DTS)

 

[Bill_Bright]

I also use the analogue outputs

I find it interesting and fascinating how interest in analog is coming back. I note the sale of vinyl records has risen each of the last 17 years! Of course, very few of them are truly analog from start to finish, but still, analog is far from dead.

 

[Calenhad]

I find it interesting and fascinating how interest in analog is coming back. I note the sale of vinyl records has risen each of the last 17 years! Of course, very few of them are truly analog from start to finish, but still, analog is far from dead.

I never stopped. Or rather, I tested the DD and DTS encoder via optical and there is a 0.5-1 sec lag. In certain games (the pew pew kind) that will get me killed from time to time. For other content such as streaming it is no more than the brain can re-sync. But when you listen for a reload complete sound or similar, that is enough to cause trouble sometimes.

And the ZxR have well spec'd analogue outputs. I am sure the DACs beat whatever the Z906 got.

 

[Bill_Bright]

Well, I have over 600 LP vinyl albums, as well as my dad's collection of another 300 going back to the late 50s and 60s. And while I have an equal number of CD, I still like the vinyl sound too - pops and scratches and all.

 

[Ferather]

'Well, 6-channel PCM support is not possible via SPDIF. It is bandwidth limited to 2-channel PCM or 6-channel encoded audio (Dolby/DTS)'

Not true, not even a bandwidth issue, SPDIF has no set bandwidth, wish people would stop saying that, TOSLink has been 125mbs for years.
Sure in 1983 when TOSLink was only capable of 3mbps then you can indeed only do 2 channels with that much.



15 channels with don't care mode, which I translate to any number. 8 channel SPDIF receiver (Cirrus Logic).
Just to point out the only bottleneck is HDA with a max of ~37mbps, inc HDMI.

 

[Calenhad]

The original design spec for SPDIF was like that, and every piece of hardware I own with optical out follow this limitation. So I presume you need higher spec hardware at both ends to exceed that, or for the right hardware I am sure you can override any driver settings. All I can say is that the last time I tried optical out on any device, I was still limited to said spec. I would be interested in what consumer products actually support this extended bandwidth without a "hack" or two. I have a couple year old oled tv, PS3 and 4, and couple pcs with optical outputs and none of them have given me the option to output more than 2 channels of pure PCM. 6 channel DD/DTS is never a problem, that is still per spec though. Honestly I don't bother with it anymore anyway. I find other options are easier, and for a digital signal it does not matter if it is transferred optically or electrically. As long as it get to the other end intact.

My chosen outputs are HDMI ARC for the home theater, since there is no potential issues with amount of PCM channels and it got automatic audio<->video sync. No need to fiddle with the audio latency settings. And as said above, I use the analogue outputs from my computer.

 

[Ferather]

Yes indeed that's the issue these days, nearly all OEMs place a 2 channel transmitter for output, and 2 channel receiver for input. Its not actually a limitation of SPDIF, but the OEM's decision.
There is hardware that accepts 6 channel 48k 24b over SPDIF, as PCM (LPCM), no compression. I also have a HDMI to TOSLink converter that does 8 channels transmit.

Lets take Realtek as an example SPDIF provider, they absolutely can replace the 2 channel transmitter they use, to a 15+ channel transmitter.
In terms of for example the Z906 (which wont be a Z906, a newer model instead), can then have a 15+ channel receiver.

BOTH, HDMI and SPDIF are connected to HDA (HD Audio, 2004), which can only put out a maximum of ~37mbps, regardless of SPDIF-HDMI and interconnect bandwidth.


Now we got close to the maximum bandwidth of TOSLink, but not SPDIF, SPDIF is limited by hardware and implementation, there are no bandwidth specs.
Even with HDMI the OEM can opt for just a 2 channel receiver and DAC, even if it accepts compressed formats, over 2 is optional.

Another way we can express that HDA is the limiting factor, while current consumer SPDIF will do 15 x 192k, that's too much for HDA.
However, we can do 15 x 96k which is just under 35mbps, where 15 x 192 is just under 70mbps. 108 x 48k 24b = 124.4.

 

[Calenhad]

That was my point. It is the hardware at both ends that matter. And it is for those the spec is set. We both know that the fiber optical cable can handle alot more. E.g. 16 channels of 48k 24b LPCM audio will use about 20mbps, assuming my lazy internet search found a credible source. Meaning you can fit about 29 channels in said 37mbps. Given the "proper" optical transmitter/receiver pair this is possible. There are long range HDMI cables that use higher bandwidth optical transmitter/receiver pairs for a similar task.

So yes, hypothetically we could have hardware that solved the problem of transferring x channels of LPCM via TOSLINK. But we are stuck with the basics, and due to the ease of using HDMI I don't think we will see that improve in the future. The current trend, as I see it, is to replace optical out with HDMI out. I have a modern 4K blu-ray player that even have two HDMI out. One video/audio. And a dedicated audio only HDMI out if you need that. But no optical out.

 

[Ferather]

And then in comes optical HDMI cables, hehe (got 4x for around £20 each). Still regardless its not a SPDIF or TOSLink issue, or a bandwidth one.
The SPDIF topic has come up a few times, but people still reference false (out of date), information, which annoys me, lol.

HDMI certainly has its uses at the consumer level, that said, I have not seen many DAW's using HDMI.
Overtime I have seen posts about lag with HDMI, but not with optical, but that can vary.

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A side note, SPDIF gets updates in the same way as HDMI and DisplayPort gets updates, new versions.
SPDIF however does not define a version, not that I know of, just current specs.

I can understand to some degree why things get confusing without a defined version to specify.


We could refer to the legacy specs as SPDIF v1.0, and current as SPDIF v2.0. (Like HDMI 1.0/2.1).
I also forgot to say SPDIF professional seems to be using AES18 not AES3.

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Forgot to mention, the current 15+ SPDIF transmitters are programmable, so speaker config can be used (same as Analogue/HDMI).
Unfortunately Windows and most apps do not support more than 8 channels in a standard layout (no height).



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(Extract from my post in another thread)

First image below, I created a bi-directional optical system for HDMI-DP. Single specific lanes of single fiber, a multi-fiber cable.

The video lane could start at 100 Gbps (NRZ-PAM2), and later move to 200Gbps (other encoding, example PAM4).
The audio and data lane can-will also have their own bandwidth, 125Mbps audio 10Gbps data.

This would require a new version, due to the built in optical transmitters-receivers (not in the cable or connector).
Blanking periods for audio-other are not required (data island period).

 

[Ferather]

GitHub - Nomis/Logitech-Z906: Unofficial Documentation for Logitech® Z906 Surround Sound Speakers (2022)

Speaker Test Mode: While on, hold the "input" button on the remote control for 5 seconds.
Enable/Disable Automatic Standby: While on, hold the "level" button for 5 seconds.
Factory Reset: While off, hold down the "input" button for 8 seconds (Note: Pops).

Fingers crossed for a Logitech D-01 (DMAS 1), SPDIF > PowerDAC, 8 channels is fine for now.

 

[Lucky8]

Sound is analog. Period. Full stop. There is NO SUCH THING as digital sound

Sound is information , as anything else in this universe. If we start discussing facts, mater does not exist. Sound exist in the digital domain is just that you happen to born a primate that can only decode information in analogical domain. Although, even that is not true. You brain works by processing data, interpreting electrical signals . If you put a speaker in you chest and you're deft, you still can get the information it just won't be converted to what you call "sound" which a very limited domain you live in . When you have a dream that involves taking with a person, in your dream, the sound exist although , there is no vibration. You got the end product. In that same way, sound does not need a "physical" medium to exist. But again, there is no such thing as something physically real. So we create -concepts - made of forms and name them according to the method of interpretation used to assimilate that information. That's why is perfectly acceptable to call sound to any digital information that contain vibratory data.

@Ferather I'm experimenting with restoring sound spatialisation to some older computer games . damn it is interesting. Using a crappy pair of headphones getting higher order ambisonics. The sound is immersive enough to make me want to buy speakers to really experience it in a non-cheap way. I meant that figuratively cause I'm on a budget . so here I am coming for wisdom . Any suggestion on building a starter 7.1 setup?

 

[Bill_Bright]

Sound exist in the digital domain

LOL

No it doesn't.

Please explain to us what a 1 (high voltage) or 0 (low voltage) "sounds" like. Or what it "feels" like.

If you put a speaker on your chest, what you now perceive as sound is still "vibrations" caused by the speaker's "analog" movement, pushing air in an "analog" way.

It is not digital, and neither is sound.

 

[Lucky8]

LOL

No it doesn't.

Please explain to us what a 1 (high voltage) or 0 (low voltage) "sounds" like. Or what it "feels" like.

If you put a speaker on your chest, what you now perceive as sound is still "vibrations" caused by the speaker's "analog" movement, pushing air in an "analog" way.

It is not digital, and neither is sound.

Then explain to me why you're not even in front of me and I can hear you voice ? It is information. And what changes is the way you transport it.

 

[Bill_Bright]

Then explain to me why you're not even in front of me and I can hear you voice ?

Wow. If you don't understand the answer to that, then you need to take a basic, 7th grade Physical Science class so you can learn a little how sound "waves" travel through a medium, such as air, before you say more and dig yourself deeper into this silly hole.

"Sound" is not information. It is energy. It may contain information, but it is not information any more than an electron or photon is information. But just because something is information, that does not mean it is digital, or analog. For example, the word "STOP" on a Stop sign is information.

What is sound?

 

[Lucky8]

Wow. If you don't understand the answer to that, then you need to take a basic, 7th grade Physical Science class so you can learn a little how sound "waves" travel through a medium, such as air, before you say more and dig yourself deeper into this silly hole.

"Sound" is not information. It is energy. It may contain information, but it is not information any more than an electron or photon is information. But just because something is information, that does not mean it is digital, or analog. For example, the word "STOP" on a Stop sign is information.

What is sound?

Yes, you - read - "stop" . Using your eyes. Meaning you convert light impulses that permeate your retina to information ( more electric impulses ) that you brain decodes. Same way it decodes vibratory information. So your senses are information interpreters.
Now, video-call your mom and tell that you've to stop communicating that way cause you have realised she is being replaced by a malign digital version of hers.
About that 7th grade class regarding "waves" . Do you know why photons can move as waves or particles regardless the medium they are in ? Because they are like me. They don't give a crap about anecdotal limitations

 

[Bill_Bright]

Nothing anecdotal about what I said. Just the facts.

Not one thing you said above has anything to do with digital. Our brains do not interpret light impulses digitally. Same with sound "waves" that hit our ears. Sorry you don't understand that - but your lack of understanding (or agreement) is no excuse for you degrading the thread with puerile insults.

And for the record, my mom has been dead for over 25 years. So I would appreciate you keep your crass, childish and insensitive comments out of these technical discussions.

Time to move on.

 

[Ferather]

Lightly off topic you two, but I am ok with that. We certainly hear analogue that is 100% true, waves passing through air (which is what a speaker mimics).
However, device waves are produced via power, whereas for example talking, does use energy, but not electricity to produce the waves.

Life does not use electricity to produce sounds, that would be so funny to see (running around with analogue amps).

In terms of storing sound, that's a bit different. For digital audio you can't get better than PCM, you can reduce the bitrate via compression though.
Even FLAC is compressed PCM, its not like a utterly new format has been produced, its decoded-uncompressed to PCM for playback.

Also not to sound offensive but its not logical to convert digital to power early in the system, you want conversion at the speaker.

 

[Ferather]

Stop being rude both of you. Not achieving better speakers. Also the Logitech Z906 is Class D, makes me wonder if it has a DAC at all (maybe for headphones).
The power stage needs improvements, 10% THD at 500w RMS is high, 0.1% THD at 500w RMS would be a massive upgrade.

 

[Bill_Bright]

However, device waves are produced via power, whereas for example talking, does use energy, but not electricity to produce the waves.

Exactly. That is why I said above sound is energy. In terms of voice, it is the energy produced by air being expelled through muscle action across our vocal cords, causing them to vibrate.

Also not to sound offensive but its not logical to convert digital to power early in the system, you want conversion at the speaker.

Not sure who that might offend. It does not me because that makes perfect sense. In fact, because moving and storing (and even manipulating) digital information consumes so little power (and space), that is one reason (out of many) digital has proliferated over analog.

Not trying to be rude. Just stating facts. Sorry if it sounded that way. Physical Science was, in fact, a 7th grade topic when I went to school - and not an elective either. So no rude intentions meant. And in Physical Science is where we learned many of the basic principles of physics, including soundwaves and how they move through different mediums like gases, liquids and solids (but not a vacuum). So again, just the facts.

 

[Ferather]

We are now on the same page, xD.

When it comes to direct digital transmission, there is only SPDIF, HDMI or USB. Although I think USB mimics an interface, not 100% sure.
I did notice the USB side of the PowerDAC listed at the top of page 2, was SPDIF over USB, opposed to Headphones.

You can argue wireless methods, but they are a double negative, direct loss, and impact on other equipment (as EMI-RFI).

 

[Mindweaver]

This is a warning, If you feel like you need to resort to name calling then please step away from the thread.

 

[Bill_Bright]

Although I think USB mimics an interface, not 100% sure.

Well, it is an interface. There are, USB headphones, for example, as you noted. Though USB is not something I would probably recommend for a serious home theater setup.

As for wireless, don't discount them just yet. I would suspect the Formation Duo speakers for $5000/pair sound pretty darn nice - and without any loss or EMI/RFI "artifacts".