• Qoke
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Topic: Async SRC Recommendation

Hi there, I am looking at a high quality asynchronous SRC solution.

The workflow configuration here would be:

Digital Source (SPDIF out) - > ((SRC Solution)) -> (SPDIF or ADAT in) DSP (SPDIF or ADAT out) -> ADI-2 DAC FS -> Analog

Based on recommendations on here and other forums, I have been looking at:

1. ADI-2 Pro FS BE
- My top pick, but has an understandably much higher price tag given the huge amount of other included functionality (AD/DAC/USB interface) that wouldn't be used in this use case

2. RME ADI-192 DD
- More cost effective that the ADI-2 solution (esp if sourced 2nd hand), however also an older solution, so I'm not sure how it compares in terms of SRC quality to the ADI-2, so if anyone from RME has any input on these 2 it would be much appreciated.

3. TI SRC4392 or AKM 4137EQ based boards
- Some "DIY audio experts" swear by these boards, but I haven't found many commercial audio expert opinions on the TI SRC4392 or AKM 4137EQ, apart from one statement on here that suggested the software based SRCs like HQPlayer produce better results than the AK4137
- Unfortunately not all the content I need to SRC is PC based, so I can't rely (solely) on a software solution, I do need a hardware based SRC
- Is the TI SRC4392 any better than the AKM 4137EQ ?
- Will I get any discernible quality improvement going with the ADI-2 Pro or ADI-192 DD over a SRC board?

  • ning
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Re: Async SRC Recommendation

If you want SRC and DSP between your digital source and DAC, why not consider getting a raspberry pi4 (with spdif head)? It's within $70, and can do the work fairly well, in realtime up to the highest sample rate ADI-2 DAC supports.

All other hardware solutions do have their own benefits (almost no latency, for instance), but none have the flexibility DSP and SRC software offers. With SRC/DSP solutions such as CamillaDSP, you can configure almost anything, including which SRC algorithm to use, the buffer size, the oversampling ratio, cut off frequency, and many others.

3 Reply by KaiS (edited by KaiS 2022-05-02 07:28:18)

  • KaiS
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Re: Async SRC Recommendation

Qoke wrote:

- Unfortunately not all the content I need to SRC is PC based, so I can't rely (solely) on a software solution, I do need a hardware based SRC

If your application doesn‘t need realtime (like a live broadcast situation), I suggest to rethink about copying the source material to your PC and do the SRC in there.

In my studio I do use ADI-8 DD’s SCR for live tracking from time to time, with good results.

ADI-2 Pro’s SRC sounds transparent too, I don’t hear any difference to the source.

Take these results with a grain of salt - due to the different sample rates a true blind A/B comparison is not possible.
The DA-filter comes across.

For offline SRC I use r8brain if a precise time/SR matching is necessary, like in audio for video work, as r8brain allows arbitrary sample rate ratios.

For more simple adaptions my Sequoia DAW has top notch offline SRC built in, even with batch processing.

KaiS's Website

4 Reply by Qoke (edited by Qoke 2022-05-02 07:14:49)

  • Qoke
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Re: Async SRC Recommendation

ning wrote:

If you want SRC and DSP between your digital source and DAC, why not consider getting a raspberry pi4 (with spdif head)? It's within $70, and can do the work fairly well, in realtime up to the highest sample rate ADI-2 DAC supports.

Thanks for the heads up.

I probably should have mentioned in the original posting that another reason I want to avoid a software solution is latency introduction, especially if the latency offset is different for different input sample rates on the SRC, which is the case on some realtime software-based SRC solutions. This is because it will cause A/V offset / lipsync issues.

I will look into the solution you are suggesting though, and see it handles buffers/latencies for various input sample rates.

  • Qoke
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Re: Async SRC Recommendation

KaiS wrote:

If your application doesn‘t need realtime (like a live broadcast situation), I suggest to rethink about copying the source material to your PC and do the SRC in there.

Yes, this is for live broadcast, with a 96k multitrack recording and 2 mixdown recordings as well (one in 48k which is the program/broadcast audio, and one in 96k for archive and VIP listeners). The 96k mixdown track is also distributed to the channel VIPs who are "discerning listeners" for review of the live audio comparisons, and who provide their input/feedback, which is why the quality of the SRC is so important.

KaiS wrote:

In my studio I do use ADI-8 DD’s SCR for live tracking from time to time, with good results.
ADI-2 Pro’s SRC sounds transparent too, I don’t hear any difference to the source.

Thanks, I'm still leaning towards the ADI-2 Pro or ADI-8 DD as my SRC solution, so its great to hear you've had great results on both of these.

  • ning
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Re: Async SRC Recommendation

If latency is a concern, spending $2000 on an ADI-2 Pro is a wise solution.

7 Reply by MC

  • MC
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Re: Async SRC Recommendation

The SRC of the ADI-192DD (TI SRC4192) is on par with the AK4137, just lmited to 192 kHz, no DSD etc. It outperforms the AK4127 used in the Pro by a few dB. So if you can get a 192 DD used it would be a perfect solution, plus gives you some more features that might be useful.

> 3. TI SRC4392 or AKM 4137EQ based boards

The 'boards' that you mentioned - I know these from AliExpress, but they are not available due to no chips available...

Regards
Matthias Carstens
RME

MC's Website

  • Qoke
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Re: Async SRC Recommendation

Thanks @MC . I appreciate the time you took to explain the details here, this has certainly sealed the deal for me - I will go with the ADI-192DD.

I also wanted to thank you for your continued amazing engagement with the community on here, it's nothing short of outstanding.

  • Registered: 2019-01-07
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Re: Async SRC Recommendation

Qoke,

I've nothing to add to the discussion beyond my own interests in hearing an on-line broadcast!   I'm totally addicted to Internet Radio, and absolutely love my Global Jukebox!   Never at a loss for material.

For whatever it's worth, WDR2 (DE) has one of the more desirable streams...  Very Clean.

If you have something?   I would be completely willing to add it to my Favorites!

Thanks in advance.

Curt

Vintage 2018 ADI-2 DAC. "Classic AKM4490 Edition"
Cables:  Red, and White Ones.
Speakers:  Yes
  • Qoke
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Re: Async SRC Recommendation

@Curt962 - Sadly whilst the broadcast is a "live" stream, it is only "live" inside the bounds of the University VPN and campus due to content licensing rights. It started off as nothing more than a basement science project by a few guys in the Music and CompSci departments, but thanks to COVID it turned into a platform that brought people together, so much so that they had scaling/capacity issues.

I was asked by a friend to help them with their playout scaling issues (it's all unicast, and the VPN concentrators became a bottleneck), and then I got roped into helping rebuild the studio workflow, which is where the SRC conversation started. This is also the reason I was looking for something "good" but also not too costly, because the SRC is being donated.

I managed to get an ADI-192DD on eBay last night and I'm actually really interested to hear how good it is, I might even add one to my own studio because I don't actually have a SRC myself, I've always just used offline conversion.

11 Reply by Curt962 (edited by Curt962 2022-05-03 15:54:34)

  • Registered: 2019-01-07
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Re: Async SRC Recommendation

Qoke,

Thanks for your kind consideration!   Wishing you the best with your exciting project, and do trust that your new RME acquisition will most certainly help you to accomplish your objectives.

Best Regards for a fine result.

Curt

Vintage 2018 ADI-2 DAC. "Classic AKM4490 Edition"
Cables:  Red, and White Ones.
Speakers:  Yes