Introducing DSPi | A powerful, user friendly and open source DSP for less than a cup of coffee

[Weeb Labs]

Thanks.

I ran the downgrade, shows successful:

View attachment 514027

The console still shows the 'no usb devices' message.

I checked Device Manager and the DSPi USB driver remains at the previous version.

View attachment 514026

What am I doing wrong?

You may need to disconnect and reconnect the DSPi or reboot. If neither solves the problem, please try the Update Driver function, choose Select from list and then select the 6.X version.

 

[bogdansrb]

Ok, full codecs with analog in. Even the DAC section is mid-fi at best, especially in the AK4619: 91 dB SINAD typ., 80 dB min at 48 kHz, worse at 96 kHz. Commercial gear with those kind of codecs is never audibly transparent in my experience. How about AK4458? It plays in a different league at 107 dB SINAD per spec sheet. I have seen distortion measurements of the Aurora DSP, harmonics AFAIR were all in the < - 100 dB range, and that is with output stages that were not particularly optimized. This is also the family of DACs used in the Hypex plate amps. You would need to use a AK5552 or 5558 ADC, depending on number of input channels needed, that plays in the same league as the DAC.

Yes the 4458/5552 is probably the best combo you can get, but AKM had some stock issues and I couldn't find them back then. Not sure now.

 

[Rocky Maine]

OK, driver is updated :

But console still not happy. I've rebooted a few times.

 

[Kingsnake]

Troy, Are there any plans to add dynamic loudness compensation to DSPi in the future?
Ideally something gain-linked, where bass boost scales automatically with master volume, similar to RME’s loudness implementation, rather than fixed presets.
Would that be feasible within the current DSP architecture?

 

[Wesseling Audio Lab]

@Rocky Maine - you could try turning off Enhanced Protection in Smart App Control

 

[Rocky Maine]

@Rocky Maine - you could try turning off Enhanced Protection in Smart App Control

It's defaulted OFF, I believe due to my security app. Thanks for the suggestion tho.

 

[Weeb Labs]

We now have working SPDIF input.

This is currently experimental but a production ready implementation is never too far away.

 

[olieb]

We now have working SPDIF input.

Great!
The input format is PCM16 or PCM24?

 

[Weeb Labs]

Great!
The input format is PCM16 or PCM24?

Both are supported.

 

[Sonic-Wall]

Let me check when I’m back home. Can you also tell me the sampling rate as well?

It‘s 48kHz. I also notice under the „Stats for Nerbs“, that the clock frequency of the Pico was 307MHz.

 

[giubeppe]

It‘s 48kHz. I also notice under the „Stats for Nerbs“, that the clock frequency of the Pico was 307MHz.

@Sonic-Wall, I tested all frequencies and bitrates with success (44,48,96 at both 16 and 24 bit), but everything seems to work fine my side. Clock frequency is set at 307.2 MHz on my side. What IIS DAC are you using and what pins are you using? On my side I have: DIN: GPIO22, BCLK: GPIO 26, LRCLK/WS: GPIO 27.
In the interim I'm working on building an IIS analyzer to validate bitrate and check for any errors.

 

[TurtlePaul]

Troy, Are there any plans to add dynamic loudness compensation to DSPi in the future?
Ideally something gain-linked, where bass boost scales automatically with master volume, similar to RME’s loudness implementation, rather than fixed presets.
Would that be feasible within the current DSP architecture?

It has had this from the start?

 

[nullpointerninja]

We now have working SPDIF input.

View attachment 514041

This is currently experimental but a production ready implementation is never too far away.

Are you able to read the SPDIF control bits? I want to check if I’m able to parse the LG Sound Sync status and volume with the SPDIF input. That would make volume directly controllable with the remote when connected to an LG TV

 

[TurtlePaul]

Thank you very much for the measurements!

I believe your observations are a result of the current USB feedback implementation. I mentioned previously that my design latency is around 10ms but it can vary depending upon buffer fill and drain levels. Crucially, samples are never dropped.

When I have more free time this weekend (after SPDIF input is working), I will spend some time investigating the USB feedback to see if we can tighten a few screws.

Don’t know if this helps (I was a comp sci minor 20 years ago, so my programming ability is nil). Here is a USB audio timing implementation that seems to call intermittent +1 sample count frames when the queue is running low (and -1 when buffer is full). It is only 48khz code, but demonstrates the idea.

This may make latency lower and stable.

zephyr/samples/subsys/usb/uac2_explicit_feedback/src/main.c at main · zephyrproject-rtos/zephyr

Primary Git Repository for the Zephyr Project. Zephyr is a new generation, scalable, optimized, secure RTOS for multiple hardware architectures. - zephyrproject-rtos/zephyr

github.com

 

[Roland301]

That's the word I was looking for! Standalone!

All the other DSP's I'm aware of that are used with hifi are programmed, disconnected, and used, standalone. Like a DAC, or the WiimPro or a phono preamp.

Once the software is on, you just plug and play.

It's a bit more cost than a cup of coffee, to be fair, and a bit more time, which has value in its own right. It's still in Alpha stage IMO.

MiniDSP is complete, which may well be what many seek, just something that works.

Credit to the developer but it's a LOT of effort if you don't have a RaspberryPi of *any* flavour set up. I don't.

I just want something that works!

GB

For the $20 I spent on a Pico 2W and breakout board, plus the 5-10 minutes needed to flash the firmware (drag and drop a file) and wire in an RCA connector, I would say this very much "just works". Just a tiny bit of assembly required.

The software is user friendly, setup is minimal, and more features are being added at a very quick pace. Once the SPDIF input support is released, DSPi would satisfy my own use case for which I was previously considering the digital version of MiniDSP Flex ($500).

It doesn't come in a pretty case, sure, but you would need to spend hundreds of dollars for a similar feature set in a commercially available product, to my knowledge.

 

[bmc0]

the "reverse IIR" algorithm described in this paper may be feasible.

I've managed to figure out how to extend this algorithm to any (stable) biquad and arbitrary cascades thereof with minimum latency. I'm no math wizard and have no formal background in digital filters, so it took me a while . @Weeb Labs: If you're interested in adding this to DSPi at some point, I can probably help.

 

[capslock]

Yes the 4458/5552 is probably the best combo you can get, but AKM had some stock issues and I couldn't find them back then. Not sure now.

In stock now and both of them together are a lot cheaper than the AD1938

 

[bogdansrb]

I'm having the same issue as @Rocky Maine , but I don't see the 6.1 version in the Update Driver list.

In stock now and both of them together are a lot cheaper than the AD1938

AK4456/8 and AK5534 are in stock at Mouser. AK5552 has 0 stock. The only major difference I see is that 5534 has 4 ADCs.

 

[Turboscienziato]

I wanted to report a problem with the process of saving and loading equalizer data. Saving works fine, but loading them doesn't restore the decimal point. I'm use console 1.1.0 for Windows and firmware 1.1.1.

 

[IVX]

Exactly what I was beginning to mull. Which codec were you thinking of? I was pondering stereo DACs, either AK4493S, which is cheap and capable of very good performance, certainly better than most codecs I'm aware of, or ES9039QN, which is still reasonably priced, has I2S and SPDIF in and excellent performance, better even than the 8 channel 9039PRO, which has an issue with 10 kHz THD according to @IVX.

It is not really a problem, just a cheaper one ES9039Q2M has 10x times lower H3 of 10kHz. I have doubts if AK4493 H3@10k would be lower than 9039Pro, rather 9039Q2M is phenomenal, that's it.