2xWAU used as crossovers

[John61CT]

I am planning a stereo system with

"full-range" OG LS50s main pair, HPF'd somewhere between 170-300Hz

stereo MBM pair, bandpassed between LPF blending with the above, and an HPF between 70-90Hz

then mono sub(s) below that.

My idea is to use two WAU for handling the crossovers, the "top one" driving the main pair and just not using its mono sub output,

and the bottom one, where the MBM need their LPF "manual blending" at the top with the main pair's HPF

but the mono sub output can be used as is.

I was thinking, use one WAU for each L/R side but now I see no advantage to that.

I would need to use MR grouping of course for interconnects, when going to 5.x for HT, adding an Ultra (feeding Schiit SYN) to act as the "master" streamer.

At that point the WAUs are acting like those car amps with built-in DSP, just higher SQ and better flexibility for future repurposing.

Any feedback welcome but rather than just general "why?" "too pricey" or "better ways with other amps" I'd appreciate specifics on how / why this idea itself would not work, as in major flaws in my understanding of how Wiim works.

TIA

Side issue, not just for @harkpabst the WAU should deliver plenty of power/current right? Pretty close to 3e A7 mono...

 

[mrehorst]

If I understand what you're trying to do, that setup requires very accurate synchronization of the two Wiim amps right at mid bass frequencies. I wouldn't bet on the sync capability being accurate enough.

 

[John61CT]

If I understand what you're trying to do, that setup requires very accurate synchronization of the two Wiim amps right at mid bass frequencies.

That is correct.Over wired Ethernet of course.

Maybe that would be a reason for using them for Left vs Right, although that would mean all crossovers are manually adjusted.

> I wouldn't bet on the sync capability being accurate enough.

Is that just defaulting to skepticism? Or based on evidence or at least past reports?

 

[Mr Ee]

I ran two wiims as a left / right pair for a morning once, just as a test.
iirc it was a wiim amp pro to one speaker and a wiim mini/dac/marantz amp to the other speaker, both on wifi.

I only noticed an 'echo' / issue when I manually adjusted the mini's sync to be a few millisecs off centre.

However, should you want / need to delay one of the amps you can't - there is no Sync Audio menu option for amps.

Slighty off topic - the Sounds don't have Sync Audio either, so you can't adjust the sync when using them either as a stereo pair (not that I found I needed to in this scenario) nor if you have two of them in different places.
It would seem that only the 'streamer' devices have the sync audio menu option.

Oh, and if it bothers you, (currently) wiim groups are capped at 48khz.

 

[John61CT]

> only the 'streamer' devices have the sync audio menu option

Better to say, none of the AMPs have it, since the WAU has Streaming.

That seems like something that should be fixed!

So if I do have any Synch issue, seems like I could fix it by getting the (non-Amp) Ultra early and use that as Master?

I suppose I could just do that from the get go, the stereo MBM pair likely will not need as much power/current as the LS50s, FOSI v3 with a 10A psu should be plenty.

 

[Mr Ee]

Better to say, none of the AMPs have it, since the WAU has Streaming.

Yeah, I was struggling on the description.
But the Sounds are streamers too, and they don't have it.
I was thinking of writing wimis that either are speakers or connected to speakers, but that brought me back to 'streamers'.
So...

It would seem that only the 'streamer only' devices have the sync audio menu option.

 

[mrehorst]

> I wouldn't bet on the sync capability being accurate enough.

Is that just defaulting to skepticism? Or based on evidence or at least past reports?

If the mid bass xover point is 200 Hz, the period at that frequency is 5 ms. I think that would mean that unless you can sync within 1 ms, you're going to create audible problems around the crossover frequency. Syncing two devices within 1 ms of each other seems like a stretch, even for Wiim.

Of course, I could be wrong.

 

[John61CT]

Actually multiple milliseconds is a very big window, I think even with old unimpressive DSP 0.02ms is a normal increment.

I plan to use placement to start with anyway, in this case have a lot of flexibility

 

[slartibartfast]

Actually multiple milliseconds is a very big window, I think even with old unimpressive DSP 0.02ms is a normal increment.

Maybe but WiiM can't do less than 1ms yet.

 

[EddNog]

I am planning a stereo system with

"full-range" OG LS50s main pair, HPF'd somewhere between 170-300Hz

stereo MBM pair, bandpassed between LPF blending with the above, and an HPF between 70-90Hz

then mono sub(s) below that.

My idea is to use two WAU for handling the crossovers, the "top one" driving the main pair and just not using its mono sub output,

and the bottom one, where the MBM need their LPF "manual blending" at the top with the main pair's HPF

but the mono sub output can be used as is.

I was thinking, use one WAU for each L/R side but now I see no advantage to that.

I would need to use MR grouping of course for interconnects, when going to 5.x for HT, adding an Ultra (feeding Schiit SYN) to act as the "master" streamer.

At that point the WAUs are acting like those car amps with built-in DSP, just higher SQ and better flexibility for future repurposing.

Any feedback welcome but rather than just general "why?" "too pricey" or "better ways with other amps" I'd appreciate specifics on how / why this idea itself would not work, as in major flaws in my understanding of how Wiim works.

TIA

Side issue, not just for @harkpabst the WAU should deliver plenty of power/current right? Pretty close to 3e A7 mono...

I tried this using a WiiM Ultra for the speakers (a pair of LS50 Metas), a WiiM Pro Plus for the upper bass (a pair of SVS 3000 Micros), and an SVS PC-2000 Pro (sealed mode) attached to that for low bass. The upper crossover between the WiiM Ultra and the WiiM Pro Plus was 160Hz. The PC-2000 Pro was crossed in at 70Hz.

I will tell you now, it was a fool's errand because the delay between the two WiiMs was never consistent. You might get it calibrated one day and the next time you listen, it is now off by some milliseconds, throwing everything off. At 160Hz, this was already bad. At 300Hz, you can absolutely forget about it. THIS is the main problem.

Use forum search for the term 2.2.1 and posts from me and you'll find details. Just what is it about KEF LS50s that make us want to do these crazy things?!

-Ed

 

[John61CT]

OK great data points, thanks.

The LS50 has such a crazy great sound, but start distorting below 200Hz at high SPL.

A good audiophile quality DSP with enough channels costs as much as I'm investing in the whole rest of the system

I guess I might experiment with DC-powered amps designed for automotive audio, or even dedicated crossovers. Good stuff there isn't cheap either...

 

[John61CT]

> one WAU for each L/R side

I wonder if timing issues are less critical going that way?

 

[EddNog]

> one WAU for each L/R side

I wonder if timing issues are less critical going that way?

This is probably even worse. Your image will destabilize terribly.

OK great data points, thanks.

The LS50 has such a crazy great sound, but start distorting below 200Hz at high SPL.

A good audiophile quality DSP with enough channels costs as much as I'm investing in the whole rest of the system

I guess I might experiment with DC-powered amps designed for automotive audio, or even dedicated crossovers. Good stuff there isn't cheap either...

Honestly? My best advice is to try to find a miniDSP Flex. Use it for handling the crossover of the two top tiers (use digital output from WiiM to the miniDSP) and then use the WiiM itself to handle blending in the sub.

-Ed

 

[John61CT]

If I do go standalone D$P I'd want enough output channels to handle the whole system, maybe do Dirac one day.

ADAU1452 based boards might be worth learning about, but the simplicity of the automotive stuff is attractive.

AudioControl with their plugin modules seem to offer good SQ

 

[EddNog]

If I do go standalone D$P I'd want enough output channels to handle the whole system, maybe do Dirac one day.

ADAU1452 based boards might be worth learning about, but the simplicity of the automotive stuff is attractive.

AudioControl with their plugin modules seem to offer good SQ

The new miniDSP Tide16 looks delicious...too bad I'm not rich!

-Ed