Inconsistent Delay or Latency in Audio on Conjoined Speaker Pairs

[SoonToBeRetired]

I live in a small apartment in Brooklyn (most apartments in Brooklyn are small). But I still manage to have two “Main Listening Positions” in my office/dining room/living room kitchen area, which is really one space but for psychological reasons I like to believe are different spaces. I have one audio source, an iMac computer on which I also do all my other computer activities such as writing and web surfing (with no audible ill effects). I mostly listen to streaming classical radio stations (WQXR in NYC) and Qobuz. The computer sits on a desk on which I have a pair of Kali LP UNF speakers fed directly from a USB on the iMac. When doing work on the desk, I have these speakers play exclusively.

In the “Living Room” i have a pair of floor standing speakers with my listening position set at the corner of a small Isosceles Triangle. They are powered by a Rotel power amplifier fed by a pre-amp fed by a Cambridge Audio Dacmagic 200m in DAC mode. The DAC is fed from another USB port on the iMac.

I select the sources using SoundSource. I have created a “Multi Output Device” with Apple's MIDI utility, and when I want to have both sources playing—when I’m going back and forth to the Kitchen, etc., so I can theoretically have a decent stereo sound throughout my apartment and while sitting at my desk or chair. (I know its crazy).

Here is the problem. Some days when I select the Multi Output Device, the pairs of speakers are synchronized to my ears—the announcers on WQXR speak without any echoing. Other days, there is a distinct echo which I believe is caused by a delay in one of the speaker systems. I guess I could accept the reasoning that the longer signal chain for the floor standing speakers cause them to be slightly behind the Kalis, but why are they in synch on SOME days? Any ideas? I've tried switching the DAC on both before and after I switch on the Kalis in the morning, but that doesn't seem to change things one way or another.

 

[Roland68]

I live in a small apartment in Brooklyn (most apartments in Brooklyn are small). But I still manage to have two “Main Listening Positions” in my office/dining room/living room kitchen area, which is really one space but for psychological reasons I like to believe are different spaces. I have one audio source, an iMac computer on which I also do all my other computer activities such as writing and web surfing (with no audible ill effects). I mostly listen to streaming classical radio stations (WQXR in NYC) and Qobuz. The computer sits on a desk on which I have a pair of Kali LP UNF speakers fed directly from a USB on the iMac. When doing work on the desk, I have these speakers play exclusively.

In the “Living Room” i have a pair of floor standing speakers with my listening position set at the corner of a small Isosceles Triangle. They are powered by a Rotel power amplifier fed by a pre-amp fed by a Cambridge Audio Dacmagic 200m in DAC mode. The DAC is fed from another USB port on the iMac.

I select the sources using SoundSource. I have created a “Multi Output Device” with Apple's MIDI utility, and when I want to have both sources playing—when I’m going back and forth to the Kitchen, etc., so I can theoretically have a decent stereo sound throughout my apartment and while sitting at my desk or chair. (I know its crazy).

Here is the problem. Some days when I select the Multi Output Device, the pairs of speakers are synchronized to my ears—the announcers on WQXR speak without any echoing. Other days, there is a distinct echo which I believe is caused by a delay in one of the speaker systems. I guess I could accept the reasoning that the longer signal chain for the floor standing speakers cause them to be slightly behind the Kalis, but why are they in synch on SOME days? Any ideas? I've tried switching the DAC on both before and after I switch on the Kalis in the morning, but that doesn't seem to change things one way or another.

First of all, before investigating anything else, I would turn off SoundSource or better yet, uninstall it and then test it again for a few days.
Otherwise you're chasing a white rabbit that may not even exist.

 

[Dimitri]

Kali LP UNF speakers fed directly from a USB on the iMac.

Rotel power amplifier fed by a pre-amp fed by a Cambridge Audio Dacmagic 200m in DAC mode. The DAC is fed from another USB port on the iMac.

but why are they in synch on SOME days?

If I understand correctly, one DAC is feeding the Kali speakers and another DAC is feeding the Rotel.
Any "sync" is by coincidence since one DAC is doing it's own converting independently and unsyncronized fromeach other.
Same effect when going into a store and on the "wall of TVs" they have more than one TV sound on;

Sure, there are ways to keep digital signals in sync, but that's a solution of a different magnitude.

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You best bet is to "share" the audio using the analog side. Either feed the kali from the the rotel, or skip the dacmagic and use the mac's audio output that feeds the kali, to also feed the preamp.

 

[SoonToBeRetired]

Update is that the "delay" has been greatly reduced or eliminated when I removed "SoundSource" from the "signal chain". It seems to have caused the delay, albeit inconsistently which is kind of puzzling. As far as "sharing" the audio on the analog side of things, that's not possible with the Kalis as I understand them in that if one choses to feed them with an analog signal via the RCA connections, the signal is converted to digital so that it can be processed by the internal DSP--the DAC in the Kalis is always used.

 

[DWPress]

If you have created an aggregate device for multiple outputs within AudioMidi Setup that is probably the problem. Even though Mac handles it better than other OS's there will be a clock drift between the DACs in the Kalis and Cambridge. Presuming you don't have any DSP going on the stereo pairs, which can also introduce latency, the only way you're going to get around this is with a 4ch DAC. Might as well get a 6ch DAC so you can integrate a subwoofer at some point as well. SoundSource shouldn't be introducing any latency unless you're using FIR or other plugins in the effects chain.

The other option is to split the analog output and just accept the extra A/D conversion as you'll probably not hear a difference anyway.