Principles: Time of Arrival Delays, vs Phase tuning ?

[Sigberg Audio]

@john61ct

I'm so confused that I get FOMO about figuring out what you're really asking here, so I'm diving back in.

I suggest you ask a single question at a time, and then pursue that to completion (until you fully understand the answer), before asking another.

I will start with one of my own. It appears you are planning on designing a multiway speaker, where not all the ways (hm) are in the same enclosure, and potentially not even colocated with the additional enclosure(s). Is that correct?

 

[-Matt-]

Schiit SYN to start...

What a strange device the Schiit SYN is!
I hadn't paid any attention to it before but here is Amir's review:

https://www.audiosciencereview.com/...ds/schiit-syn-dac-preamp-hp-amp-review.68198/

Amir makes the following observation:

I did not expect a product introduced in 2023 to be already discontinued but I can see why: few if anyone wants an analog stereo to 5.1 upmixer. There is no reason to not perform proper Dolby Digital 5.1 decoding as a minimum.

I can see now why you are following this 5.1 upmixing but not surround decoding path. It is tailored to the capabilities of this peculiar device.

 

[john61ct]

Thanks

I suggest you ask a single question at a time, and then pursue that to completion (until you fully understand the answer), before asking another.

That is not possible, sorry. My learning curve is progressing along dozens of topics, when one is stalled, later on coming back I often understand better.

.

> It appears you are planning on designing a multiway speaker.

No, those passive enclosures are purchased.

The DIYs are single driver boxen, all lower frequencies, different ranges.

Colocated and stacked, the sum of these parts emulate FR floorstanders.

Additional passband subs in mono, freely placed.

Just as an example, say one "sub1" set are 20-50Hz, "sub2" set are 50-80Hz. Total count TBD, start with 3 each for Front LRC.

Plus an MBM coupler pair just for reinforcing LS50 at F-L/R, say 80-175Hz, obviously must be fed Stereo. The sub1 + sub2 instances in the F-L/R stacks will likely be stereo, but possibly mono, to be managed possibly as groups with their freely placed brothers, by MSO.

If not then those latter may become Stereo out with Surrounds, not so freely placed.

All these decisions based of course on testing, listening not just REW graphs.

 

[john61ct]

What a strange device the Schiit SYN is!

I do like it, very much suits my preferences, can easily flip between A. 5ch simulated surround, B. 3ch stereo, and C. OG 2ch stereo

The Presence and Width adjustments are secondary to me, depends on content. My son loves those for gaming.

No real bass management afaic, hence splitting the bed channels after SYN's 5ch outputs

Center bass being a different signal from the two F-L/R bass in both A&B modes.

In C mode I still want the "non bed" additional mono freely placed subs active for tackling room effects (MSO handling all, plus maybe collocated ones if those go mono as well )

...

However as I said above, I am open to other upmixing options, testing the OG Hafler boxen, maybe even DSP-based stuff later on.

But nothing costing thousands, unless I win a lottery or my kids strike gold

 

[-Matt-]

How do you feel about pre-HDMI era AVRs?

These can be picked up second hand very cheaply (<100 moneys). If you go for a sufficiently high end one it will give you decent amps, 5.1 of even 7.1 pre-outs, proper bass management, surround decoding and proper upmixing. (You might even find one that has spdif input).

Given your aims, you would likely want to use such an AVR just as a pre amp. (You could also look for AV processors, however these are rarer and therefore more expensive). Connect your analogue DSP inputs to the pre-outs of the AVR. Set the AVR to pure direct mode if you want to disable the ancient internal DSP.

Note that the aim of the above would be to give you convenient access to stereo, 5.1 or 7.1 input streams for your DSP system but would also get you bass management (a proper subwoofer pre-out) and lots of analogue (and maybe digital) inputs. (And video switching for free if you ever want that later).

You could even consider using additional AVRs as power amps. You could do this by plugging the output signals from your DSP into the multichannel inputs and taking the amplified output from the relevant speaker terminals. (Note that you usually can't use the pre-outs and multichannel inputs simultaneously, hence why at least two AVRs would be needed in this scenario). Again use pure direct mode to disable internal DSP.

If the above sounds a bit Frankenstein, it is! However, it would still be a bit more normal that the Shiit SYN approach.


Obviously the active crossover part of your plan is another kettle of fish. MiniDSP devices hanging off the AVR pre-outs would likely be the place to start really.

 

[john61ct]

Nope. Power amps must be separate.

Running off DC not grid power.

Bass management and DSP should be as "open" as possible, as modular as possible.

I don't want to decode, but I did I's want that in a separate cheap line level device I could slip in my pocket.

I am familiar with the category, just not interested in it. I recognize you are trying to be helpful and thank you for that intention

How do you feel about pre-HDMI era AVRs?

...

If the above sounds a bit Frankenstein, it is! However, it would still be a bit more normal that the Shiit SYN approach.

Normal is a negative to me.

 

[Sigberg Audio]

Thanks
That is not possible, sorry. My learning curve is progressing along dozens of topics, when one is stalled, later on coming back I often understand better.

.

> It appears you are planning on designing a multiway speaker.

No, those passive enclosures are purchased.

The DIYs are single driver boxen, all lower frequencies, different ranges.

Colocated and stacked, the sum of these parts emulate FR floorstanders.

Additional passband subs in mono, freely placed.

Just as an example, say one "sub1" set are 20-50Hz, "sub2" set are 50-80Hz. Total count TBD, start with 3 each for Front LRC.

Plus an MBM coupler pair just for reinforcing LS50 at F-L/R, say 80-175Hz, obviously must be fed Stereo. The sub1 + sub2 instances in the F-L/R stacks will likely be stereo, but possibly mono, to be managed possibly as groups with their freely placed brothers, by MSO.

If not then those latter may become Stereo out with Surrounds, not so freely placed.

All these decisions based of course on testing, listening not just REW graphs.

OK, I will continue to ask questions (as opposed to answering) until I'm reasonably sure I understand the setup.

So my new understanding is now that you will be using Kef LS50 as left + right channel. In addition to this you have a number of subwoofers/bass modules that are all 1-way devices, and will be crossed over at various frequencies (for some reason)? And in addition to that you have some midbass modules that will be overlapping with the Kef LS50s?

Summarizing briefly from your post:

Sub set 1: 20-50hz (driven externally by something or other)
Sub set 2: 50-80hz (driven externally by something or other)
Midbass set: 80-175hz (driven externally by something or other)
Kef LS50: 80/175(?)-20,000hz? (active)

So essentially a 5-way system? With potentially independent DSP for all channels?

How (and why?) have you arrived at such a complicated solution? It feels a bit like you are intentionally designing it to be as complicated as possible to integrate?

 

[JanRSmit]

Interesting, 67 posts to explain just the time domain of music reproduction.

 

[-Matt-]

Interesting, 67 posts to explain just the time domain of music reproduction.

It doesn't achieve anything as worthwhile as that!

 

[john61ct]

midbass modules that will be overlapping with the Kef LS50s?

How much overlapping, or not TBD.

Amps are amps, the lower ones need more power.

> So essentially a 5-way system?

The F-L/R, LS50 are OG passive, so from crossover POV 4-way.

Center maybe only three.

Surrounds choices above.

> With potentially independent DSP for all channels?

Potentially, but only as needed, maybe none.

> How (and why?)

Again, the learning journey is all, the destination "success vs failure" less relevant.

As I gain experience and refine my desires then it may get simplified

 

[Waveform Fidelity]

Running off DC power and concerned about clock drifts at <5ppm - I find entertaining too

 

[john61ct]

What is ppm?

I do not know for sure what I should be concerned about or not, that is the point of the thread.

I don't see how AC vs DC power makes a difference. For thirsty gear quality inverters are pricey and drain the storage bank faster, but for small draws NP so long as clean sine-wave type.

 

[Waveform Fidelity]

What is ppm?

I do not know for sure what I should be concerned about or not, that is the point of the thread.

I don't see how AC vs DC power makes a difference. For thirsty gear quality inverters are pricey and drain the storage bank faster, but for small draws NP so long as clean sine-wave type.

PPM = parts per million a common why to specify oscillator drift.

AC vs DC doesn't make a difference, in your scenario. The power supply inside your amp converts AC/DC and filters the incoming AC to remove noise and transients and has to be designed to meet strict regulator emissions. Going off grid, means you are generating your own inverter AC (inferior to main supply) which is the converted to back to DC by your amplifier supply anyway ps o you are not running on DC as your said ^^
Instead of trying to fix a non-problem, my recommendation is to look at your amplifier specs and look for output residual noise, this will contain amongst other things like power supply noise. See how many volts it is. Modern class D amps have noise in the microvolts region and are insignificant compared with the “volts” of the music signal.

Just my 2 cents in the spirit of forum education

 

[Sigberg Audio]

That is not possible, sorry. My learning curve is progressing along dozens of topics, when one is stalled, later on coming back I often understand better.

I can appreciate that, but currently you are asking so many questions and not necessarily very clearly, so it is difficult to assist with your learning journey. By making it easier for those trying to help you, it may speed up your learning journey - as you may actually receive some clear answers.

I understand you have many questions and topics in your head at once, so I'm not necessarily asking you to forget all of them except one, but possibly try to articulate only one of them in each post.

 

[MaxwellsEq]

I'm finding it very tricky to keep track across all your posts @john61ct such that if you aren't confusing yourself, you are certainly confusing me.

You have a project in mind and you want to learn, both of which are great. You have un-costed access to deeply knowledgeable and experienced people here are willing to try and help, but you've got to help them a bit in return by not shooting off in hundreds of directions as questions arise in your mind.

I always find a drawing is a great starting place. At this point, you don't really need component or a functional drawing, but a labelled black-box type sketch would probably help us all!

 

[thcdru2k]

I think he might be confusing absolute delay with relative delay

 

[john61ct]

AC vs DC doesn't make a difference
...
Instead of trying to fix a non-problem

The only problem DC fixes for me is there is no AC power when I am off grid, by definition.

My preference is to choose components designed to plug into DC directly, especially thirsty ones, rather than having to run everything through inverters.

I have no need to discuss all these off-topic issues further here, other than answering specific questions y'all may think are relevant to the OP.

Principles: Time of Arrival Delays, vs Phase tuning ?

@john61ct Then then the next step I suspect is to differentiate between the issue of building a single speaker, and the issue of making the whole system work coherently together. Since you are going multichannel, the latter is probably easiest to do by simply purchasing an AVR that have all of...

www.audiosciencereview.com

Principles: Time of Arrival Delays, vs Phase tuning ?

@john61ct Then then the next step I suspect is to differentiate between the issue of building a single speaker, and the issue of making the whole system work coherently together. Since you are going multichannel, the latter is probably easiest to do by simply purchasing an AVR that have all of...

www.audiosciencereview.com

...

I will when ready be trying to see if this is a possible way forward

is this a valid way of synchronizing two USB DACs?

It has been discussed here millions of times: you can't just use various USB DACs simultaneously to have a multichannel system because they are not synchronized and will drift apart. But yesterday watching the last video at eevblog, where he talks about crystal oscillators, he mentions what...

www.audiosciencereview.com

Not just for AES, but SPDIF, the sender (dumb splitter hub say) controls the master clock, slave DACs are actually controlled by the timing signals inherent in the music content stream?

 

[john61ct]

I think he might be confusing absolute delay with relative delay

He?

AFAICT all the delays I am investigating are concerning to me in practice, only when they impact overall SQ.

Overall latency is not an issue for me, so for example if a given pressing time domain problem is more easily solved just by using FIR filters from the beginning then I may do that, fully replacing my initial crossover approach.

...

I think relevant questions here

SMSL SU-2: a dumb, wasted opportunity

I have to believe the network based AoIP protocols that ensure clock sync are used for good reason in pro environments SMPTE ST 2110, Ravenna, AES67, Dante, Q-LAN My quandary (besides cost) is that I want RPi being fed 6 (or more) **different** analog signals to stay in sync. I'm starting to...

www.audiosciencereview.com

 

[Keith_W]

I think he might be confusing absolute delay with relative delay

I am confused what the difference is. All delay is relative, i.e. it has to have a delay reference. For e.g. delay relative to what time we agreed to start the meeting, or delay relative to a tweeter, or delay relative to when the starter's gun in a race went off. What is absolute delay?

 

[john61ct]

I am confused what the difference is. All delay is relative. What is absolute delay?

I interpreted it as overall system latency?

But also, some types of delay affect the music signal as a whole, all frequencies equally?