Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature may not be available in some browsers.
Welcome to ASR. There are many reviews of audio hardware and expert members to help answer your questions.
Click here to have your audio equipment measured for free!
Do you have suggestions for an audio interface to sync both the analog mic and Okto, or can I use the Motu for that (in addition to trying it as a dac)?
I use a MOTU Ultralite Mk5 or RME Fireface 800, I purchased those interfaces for other reasons, but they have plenty of I/O functionality for acoustic measurements. There are a lot of interfaces that will work, they just need SPDIF output, mic input and analog (line) input.
Hello, just a quick update from my side as we are in the middle of the summer (well in some part of the world), things are progressing on the upcoming dsp version and I m continuing extensive tests and some optimisations. If you are interested in receiving this future version (more Mips, more functions) for crossover, equalisation, bass management up to 192k, just drop a PM or email to avdspproject at gmail describing your project and serial number and you will be entitled to receive it free of charge. After septembre, the business model may change for the new commers lets see
Enjoy the summer and the music!
Hello
we are August 31th and I was able to release the V162 documentation and all the tools for all OS on avdsp_dac8 GitHub, but unfortunately I m not able to release the firmware V162 on time as I still need to continue some testing... now need some time offf/vacation. So I plan to deliver V162 end of September
in the meantime if you are curious, you can browse the GitHub, look at the V162 pdf, even download the dspcreate utility (folder version 162) and compile some of the new examples stored in folder examples162. you can also install the vscode plugin for code highlighting which becomes a must to edit avdsp files
FYI do not use dspcreate 162 for generating bin files for your V161 firmware. Not compatible. so rename it or put it in separate folder!
here we are, will keep you posted end of September, in the mean time don't hesitate to share your findings or ideas. cheers
Hi Fabriceo. First I would like to thank you for your work on this dsp feature. While I use Jriver for dsp at the moment I see the advantage of getting rid of PC in many cases. However lack of GUI makes this product strcictly usable for technical geeks. I am pretty sure the vast majority of Okto users wont even try this out, not to mention countless time for you to explain the commands. I sugest to work on GUI first and add new features later even if it means a paid option like Dirac in AVRs.
Hi Dziemian
Thanks for your feedback. You have a good point about the GUI.
The lack of GUI and the inherent complexity (write a program, convert it , upload it , test it, flash it ...) is the reason why this feature was not released officially on the Okto research catalog, since I shared it 5 years ago.
Now they are studying the possibility to make something around it. But still the technical limitation of the XU216 (small FIR, spread of the program on multiple cores) remains a constrains.
Finally another difficulty is about the real time modification of some parameters (delays , cutoff frequencies, filter shape) that cannot realistically be handled on the front panel display with a single rotary button (once the device is set in the living room).
if I had more time, I would try to create an html/java application, communicating in REST api with a local socket connected in usb to the dac... this is a topic I m exploring for another project, may be I ll leverage the experience for DAC8PRO, one day...
don't hesitate to try the solution as it is , there is a learning curve of course but it worth it
fabriceo
Hoping not to be "banned" p) by the original poster, I'm writing here for help, as I believe this is the most probable place to get a good answer/solution. So @fabriceo please don't kill me!
I'm having intermittent audio dropouts (short "skips" or silences lasting about 0.5 seconds) with my Okto DAC8 PRO in a setup where I'm converting optical S/PDIF from a Samsung Smart TV to AES/EBU input. I'd appreciate any advice or similar experiences from the community—I've been troubleshooting for a while and made some progress, but it's not fully resolved.
My Setup:
Source: Samsung Smart TV (with One Connect box, running at 220V/50Hz) outputting digital audio via optical Toslink (S/PDIF). Content is mostly YouTube videos, set to PCM stereo output in the TV's expert sound settings (no Dolby/DTS, no effects enabled).
Converter: Hosa ODL-312 (optical S/PDIF to AES/EBU XLR), powered by a 9VDC/50mA adapter originally designed for 110V/60Hz, but I'm using a step-down transformer from 220V/50Hz to 110V/60Hz. (I've also tested with a direct 9VDC/1A adapter at 220V/50Hz—no difference.)
Connection: Toslink cable from TV to Hosa, then XLR cable (claims 110 ohms) from Hosa to DAC8 PRO AES input 1.
DAC8 PRO: Running latest firmware (v1.61), in Pure AES mode. Sample rate auto-detected as 48kHz (matches YouTube output). No USB involved.
The Problem:
Audio plays fine most of the time, but randomly drops out for ~0.5 seconds, like the DAC loses sync/lock. The lock indicator on the DAC flickers or goes off briefly during these skips.
I believe this happens more often with variable-content sources like YouTube (buffering/streaming?), but less with stable test signals.
I suspect high jitter from the TV's S/PDIF output, passed through the Hosa (which doesn't reclock), causing the DAC's AES receiver or Sabre ES9028 DPLL to lose lock intermittently.
What I've Tried and Current Status:
Configured TV audio to PCM stereo, disabled all sound enhancements—helped a bit but not fully.
Cleaned Toslink connectors, checked all cables for damage—everything seems fine.
Power supply tweaks: Switched to a 9VDC/1A linear adapter (direct 220V/50Hz, no step-down)—slightly more stable, but skips still happen.
DAC8 PRO settings: In Advanced Menu, increasing DPLL BW AES from default 8 to 13-15 usually fixes the lock for a while (audio plays smoothly), but sometimes it fails even at 15 (max value). Lock is intermittent—works 80% of the time now, but not reliable.
Other tests: Tried different content (Netflix vs. YouTube), and even a different S/PDIF source (Blu-ray player)—skips are worse with the TV, so pointing to jitter from the Smart TV.
No issues with USB input —problem isolated to this optical-to-AES chain.
Next Steps:
I'm buying a higher-quality 110-ohm AES/EBU XLR cable (BJC Belden 1800F) to rule out impedance mismatch/reflections—current one claims spec but might be subpar, as well as a better Toslink cable (BJC Optical).
So........ has anyone here run into similar dropout/lock issues with optical S/PDIF sources converted to AES on the DAC8 PRO? Any tips on pushing DPLL BW AES further (is there a hidden setting?), or any other recommendations that could play nice with Samsung TVs? Thanks in advance!
I'm having intermittent audio dropouts (short "skips" or silences lasting about 0.5 seconds) with my Okto DAC8 PRO in a setup where I'm converting optical S/PDIF from a Samsung Smart TV to AES/EBU input. I'd appreciate any advice or similar experiences from the community—I've been troubleshooting for a while and made some progress, but it's not fully resolved.
My Setup:
Source: Samsung Smart TV (with One Connect box, running at 220V/50Hz) outputting digital audio via optical Toslink (S/PDIF). Content is mostly YouTube videos, set to PCM stereo output in the TV's expert sound settings (no Dolby/DTS, no effects enabled).
Converter: Hosa ODL-312 (optical S/PDIF to AES/EBU XLR), powered by a 9VDC/50mA adapter originally designed for 110V/60Hz, but I'm using a step-down transformer from 220V/50Hz to 110V/60Hz. (I've also tested with a direct 9VDC/1A adapter at 220V/50Hz—no difference.)
Connection: Toslink cable from TV to Hosa, then XLR cable (claims 110 ohms) from Hosa to DAC8 PRO AES input 1.
DAC8 PRO: Running latest firmware (v1.61), in Pure AES mode. Sample rate auto-detected as 48kHz (matches YouTube output). No USB involved.
Hi. I don't know what the problem is, but just to report success with a similar set up:
I use a ~10yo Samsung TV with OneConnect box -- Toslink to Behringer SRC2496, AES over XLR to Okto dac8. I use a non-110ohm XLR cable, but it is short. I have never experienced dropouts like you describe. I don't use the TV's built-in apps, but digital broadcast and HDMI sources work flawlessly.
I considered the same Hosa format converter, but the price was unreasonable so I found a used SRC2496. It is ugly but a lot more versatile. A Mutec MC1.1+ would be a step up, but very expensive. Previously I experimented with an HDMI audio-to-SPDIF extractor and using ARC, but this was unnecessarily complex.
Hi There !
with firmware 1.61 you have only a stereo AES input (no multichannel), so the AES signal from any connector (1..4) always go directly to the spdif receiver AK4118 which is a very good device in term of clock recovery and jitter .
as you pointed, the DPLL BW AES is still an important factor and should be set to the maximum.
It is difficult to think about a software solution in your case.
still would be good to qualify what's happen in the dac.
if you remove the cover you will see 4 LEDs
the one on the left is the XMOS status (always green), the middle is the AKM lock status and on the right (on the analog board) is the DAC status.
When an AES signal is recognised the AKM will lock and lit green permanently.
if sometime the LED is not lit then it means it cannot lock reliably on the signal.
if this is your case then the only solution is to try improving the hardware connection till the AKM is happy.
if the AKM is always lit and the DAC status is "blinking" or unlit for say half a second time to time then it means its DPLL cannot lock reliably on the I2S signal... this is where the DPLL BW AES comes into play and may find some limit.
Always be careful when removing the top cover has you have the Mains plug on the left.
Also don't touch anything inside as you may propagate Electrostaticic charges, especially in winter time
Thank you so much once again @fabriceo. You're very kind!
I'm looking at the naked board as I write this post. And using the source that "fails" the most: Spotify on my Samsung smarttv - PureAES 48 kHz PCM.
- left led is permanently ON
- center led is permanently ON
- two leds on the right: last on the far right is permanently ON; but the left one blinks for that half a second with the music skipping
What should I try then?
THD h2 and h3 are set to zero. PCM filter is set to FRMP. DSD filter to auto.
Weird symptom: watching a movie on Netflix last night DPLL was on 15 and sound started skipping almost right away; moved it to 14 and the problem was solved!
MO, thanks for your test so this is not a problem of SPDIF/AES LOCK but a problem of sensitivity of the Sabre ES9028 to a jittered I2S signal.
I have no turnkey solution for this At The Moment but will discuss this with Pavel shortly. No promise for a solution.
Dziemian, thanks for your interest on coupling 2 devices, this is possible to some extend on Mac OS with the aggregate feature.
I have recently given the V1.62 firmware to Oktoresearch including some modification in the USB fifo handling which I think will enable this. Still there might be some timing difference between the aggregated devices (like one usb frame difference = 125us). But as long as the potential difference is stable in time (not seen as a jitter) then this would be ok if each device is used for different loud speakers. Then the delay would represent a very small length difference between the listener and the loudspeaker (about 4 centimetre) and would not be a problem. Let see, I will ask Pavel what result he gets and will report here once we are clear on this.
Hoping not to be "banned" p) by the original poster, I'm writing here for help, as I believe this is the most probable place to get a good answer/solution. So @fabriceo please don't kill me!
I'm having intermittent audio dropouts (short "skips" or silences lasting about 0.5 seconds) with my Okto DAC8 PRO in a setup where I'm converting optical S/PDIF from a Samsung Smart TV to AES/EBU input. I'd appreciate any advice or similar experiences from the community—I've been troubleshooting for a while and made some progress, but it's not fully resolved.
My Setup:
Source: Samsung Smart TV (with One Connect box, running at 220V/50Hz) outputting digital audio via optical Toslink (S/PDIF). Content is mostly YouTube videos, set to PCM stereo output in the TV's expert sound settings (no Dolby/DTS, no effects enabled).
Converter: Hosa ODL-312 (optical S/PDIF to AES/EBU XLR), powered by a 9VDC/50mA adapter originally designed for 110V/60Hz, but I'm using a step-down transformer from 220V/50Hz to 110V/60Hz. (I've also tested with a direct 9VDC/1A adapter at 220V/50Hz—no difference.)
Connection: Toslink cable from TV to Hosa, then XLR cable (claims 110 ohms) from Hosa to DAC8 PRO AES input 1.
DAC8 PRO: Running latest firmware (v1.61), in Pure AES mode. Sample rate auto-detected as 48kHz (matches YouTube output). No USB involved.
The Problem:
Audio plays fine most of the time, but randomly drops out for ~0.5 seconds, like the DAC loses sync/lock. The lock indicator on the DAC flickers or goes off briefly during these skips.
I believe this happens more often with variable-content sources like YouTube (buffering/streaming?), but less with stable test signals.
I suspect high jitter from the TV's S/PDIF output, passed through the Hosa (which doesn't reclock), causing the DAC's AES receiver or Sabre ES9028 DPLL to lose lock intermittently.
What I've Tried and Current Status:
Configured TV audio to PCM stereo, disabled all sound enhancements—helped a bit but not fully.
Cleaned Toslink connectors, checked all cables for damage—everything seems fine.
Power supply tweaks: Switched to a 9VDC/1A linear adapter (direct 220V/50Hz, no step-down)—slightly more stable, but skips still happen.
DAC8 PRO settings: In Advanced Menu, increasing DPLL BW AES from default 8 to 13-15 usually fixes the lock for a while (audio plays smoothly), but sometimes it fails even at 15 (max value). Lock is intermittent—works 80% of the time now, but not reliable.
Other tests: Tried different content (Netflix vs. YouTube), and even a different S/PDIF source (Blu-ray player)—skips are worse with the TV, so pointing to jitter from the Smart TV.
No issues with USB input —problem isolated to this optical-to-AES chain.
Next Steps:
I'm buying a higher-quality 110-ohm AES/EBU XLR cable (BJC Belden 1800F) to rule out impedance mismatch/reflections—current one claims spec but might be subpar, as well as a better Toslink cable (BJC Optical).
So........ has anyone here run into similar dropout/lock issues with optical S/PDIF sources converted to AES on the DAC8 PRO? Any tips on pushing DPLL BW AES further (is there a hidden setting?), or any other recommendations that could play nice with Samsung TVs? Thanks in advance!
Have you tried USB audio out from your Samsung TV? That's what I use with my S95C, and it works perfect (allowing volume control with the TV remote) to my stereo DAC USB input. For some reason, USB audio out is locked at 44.1 khz. I suspect that my tv can even output multichannel through USB, but I am not certain.
Dziemian, thanks for your interest on coupling 2 devices, this is possible to some extend on Mac OS with the aggregate feature.
I have recently given the V1.62 firmware to Oktoresearch including some modification in the USB fifo handling which I think will enable this. Still there might be some timing difference between the aggregated devices (like one usb frame difference = 125us). But as long as the potential difference is stable in time (not seen as a jitter) then this would be ok if each device is used for different loud speakers. Then the delay would represent a very small length difference between the listener and the loudspeaker (about 4 centimetre) and would not be a problem. Let see, I will ask Pavel what result he gets and will report here once we are clear on this.
I too am interested in sync-aggregation of two OKTO DAC8PRO connected to a Windows PC, not Mac OS in my case, in pure USB mode.
I understand that each of the two DAC8PRO should be connected to one PC using a USB cable, right?
Can I expect that the sync mechanism and user's utilization would be similar to USB sync aggregation of two (or three) of RME Fireface UFX III which I referred and shared here #842 on my project thread?
With your mentioned firmware v1.62 (or later), how the OKTO USB ASIO driver recognize the two DAC8PRO; will it automatically recognize them as 16-channel DAC, I mean all of the OKTO CH-01, CH-02,,,,, CH-15, CH-16 will be automatically available through ASIO?
What would be the sync mechanism, I mean trigger (start-up/kick-off) sync and clock sync thereafter during playback of music, between the two?
Do we still need AES/EBU connection between the two for synchronization even for pure sync USB 16-Ch utilization? I mean the first DAC8PRO would be Sync-Master and the second DAC8RO would be Sync-Slave via AES/EBU sync-timing mechanism?
What would be the sync reset mechanism and its timing, if any? There would be any "sync reset" audible noise, or not?
You said that "Still there might be some timing difference between the aggregated devices (like one usb frame difference = 125us, 125 micro-second)." The maximum (inevitable) trigger (or sync clock) time lag of 125 uSec, which is 0.125 mSec, would be a little bit larger than my requirement of 0.1 mSec precision time alignment (ref. here #504 using DSP "EKIO" and DAC8PRO), but it should be almost OK, at least in my setup.
Is my understanding of "maximum time lag of 0.125 mSec attributable to USB sync time frame" OK in your possible two DAC8PRO sync aggregation on a Windows PC?
Can such maximum time lag of 0.125 mSec be considerably reduced/minimized if DAC8PRO and its ASIO driver will become fully compatible with USB 3.x or higher USB specifications by using USB 3.x USB cable to PC's USB 3.x ports?
Just for your possible reference and interest, I dared objectively measured/observed "trigger timing lags" among multiple USB-DAC units (each has its own ASIO and/or WDM-WASAPI driver) connected to one Windows PC using ASIO4ALL or VB-AUDIO MATRIX 1.2.0.5 as systemwide VASIO (virtual ASIO) routing center; on my project thread, ref. #783 and #804 (both using ASIO4ALL), ref. #1,021 (using VB-AUDIO MATRIX 1.0.2.5).
Have you tried USB audio out from your Samsung TV? That's what I use with my S95C, and it works perfect (allowing volume control with the TV remote) to my stereo DAC USB input. For some reason, USB audio out is locked at 44.1 khz. I suspect that my tv can even output multichannel through USB, but I am not certain.
My Samsung S95C tv certainly works as a USB audio out source. I simply connect one of its USB ports (in the OneConnect box) to the USB input of my DAC. The TV detects the DAC and this is shown as an option in the sound output menu. I never turn off my DAC, by the way.
My Samsung S95C tv certainly works as a USB audio out source. I simply connect one of its USB ports (in the OneConnect box) to the USB input of my DAC. The TV detects the DAC and this is shown as an option in the sound output menu. I never turn off my DAC, by the way.
MO, thanks for your test so this is not a problem of SPDIF/AES LOCK but a problem of sensitivity of the Sabre ES9028 to a jittered I2S signal.
I have no turnkey solution for this At The Moment but will discuss this with Pavel shortly. No promise for a solution.
Hi Dualazmak,
As far as I m aware, the question of supporting multiple USB Audio device with the Thesycon Asio driver was raised to them and they have no plan to make this happen. So the only solution is to use a MAC Os. may be something on linux exists which I m not aware of. Therefore I cannot answer all your subsequent questions.
One technical solution which I have been thinking some time ago was to configure a master dac8pro in 16 channel (max 96k) and extract 8 of them to send them to a slave dac8pro over the xmos Xlink channel which is available on the cpu board inside dac8pro. But that requires some code and some hardware connection between them. Also the length of the cable would be critical and then we never really worked on this scenario, but that would be possible (but limited to 96k). Recently XMOS delivered a new version of their USB Stack able to support 16channels at 192k but this requires the new chips version and a 800mhz clock, so not compatible with dac8pro.
Here we are
lets see
