DSPi users (and prospects) projects discussions

[john61ct]

As requested, to keep the main dev thread less cluttered for their internal more techie topics

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

For the longest time, I have been in search of the “perfect” inexpensive audio DSP device. Something with user friendly control software that could accept a USB input, apply PEQ, delays and other essential processing and then produce a digital output. Over the holidays, I was (un)fortunate...

www.audiosciencereview.com

I'm starting this for more user-oriented discussions.

I have evolving ideas about a system, centered on the Schiit SYN processor / preamp which only outputs analog RCA.

Which I will at some point dedicate its own thread.

But here I'll stick to DSPi related questions and issues, or generally around DSP at least.

 

[Ktacos]

I hope someone makes a DAC companion board for it.

 

[Thierry-FR]

Hi, DSPi console should take into account dot and comma for decimale numbers when filters are imported from REW that uses dot and not comma .

 

[john61ct]

OK, my first issue topic has to do with USB input, currently the only path in is from a USB host device

Interfaces and "capture cards" do not work.

Apparently the Pico "could" switch to USB host mode itself but maybe that's difficult or problematic

The only devices I plan to use that are USB hosts, already do filtering / convolving, so I find that puzzling.

In any case, S/PDIF input coming soon, apparently both inputs concurrently to enable DSPi to add multi source mixing capability.

Meantime I found this DDC I think will work

HiFiMeDIY UR23 Optical TOSlink to USB Converter

16-bit/44.1kHz up to 24-bit/96kHz

yes acts as USB host and each handles a pair if audii channels

not necessarily stereo - SYN RCA analog output channels are 2x stereo pairs - Main front L/R and Surround, plus 2x one pair in Mono, Front Center and the LFE sub, fixed 80Hz LPF

but I think that does not matter, 3x those HiFiMeDIY UR23 will just feed each channel via TOSlink to the 6x DSPi units needed.

However, what my use case really requires (and likely many others) is

So now the issue is ADC, how to get ANALOG inputs cheaply converted to TOSlink?

So far my best answer is miniDSP's PocketADC which takes RCA analog input, and outputs digital via S/PDIF TOSlink optical at 24-bit / 96kHz

Again, 3x units needed, no matter if 2x mono or a stereo pair.

Any feedback welcome, especially on whether you think these specific gizmos will work, or if you can suggest a cheaper per-channel way that still offers clean SQ.

And yes, the HiFiMeDIY becomes redundant once S/PDIF input is working...

 

[john61ct]

Hi, DSPi console should take into account dot and comma for decimale numbers when filters are imported from REW that uses dot and not comma .

this should go to the OG development thread

 

[bogdansrb]

I hope someone makes a DAC companion board for it.

I'm working on this. For now with the AK4619, but I'll be doing boards with AD1938 and AK4456/AK5534.
The goal is to have audio in - audio out and possibly spdif in - audio out. I'm waiting for I2S functionality to be "official".

 

[Red_Red]

For my part, I have several objectives/projects:

First, managing the active crossover of my DIY 3-way speakers (I'll get around to writing a separate post about it someday).

To this end, I'm thinking of going for a sort of hybrid between the MiniDSP NanoDigi and the Flex 8 (I own both), but I regret that MiniDSP has somewhat abandoned DSPs with purely digital outputs (especially in this case, four digital stereo outputs like the NanoDigi).

So basically, my idea is to more or less replicate the NanoDigi's connections, meaning at least two digital inputs, plus a USB input and four digital outputs, all with Toslink connections (except, of course, the USB input).

All of this housed in a box with a clickable dial (for source selection/volume adjustment), a screen to display these values, an IR receiver—in short, just like the Flex 8. Everything controllable via IR, the dial, and the Wi-Fi/Bluetooth integrated into the Pico.



Secondly, I'm developing other DIY speakers (for family and friends), and here again, I'd like to stick with active crossovers, but this time with analog outputs for practicality. However, I'm uncompromising on the intrinsic quality of the DAC or ADC expansion modules that could be used for this purpose. Currently, I'm researching, but I haven't found anything truly simple, with reliable data, and above all : inexpensive. Alternatively, I could always implement passive crossovers and use the DSPi as described below...



Finally, a simple PEQ interface for headphones or room correction for a 2.0 or 2.1 system. But that's already possible with the current state of the DSPi. In fact, that's the most brilliant point I find: for, say, 35-40 euros/dollars max, you can get a small device that allows you to do this quite easily if - for now - you stick to USB to Tolsink (+ DAC) ! Of course, when you can add more inputs it will be even better.

 

[Ktacos]

I'm working on this. For now with the AK4619, but I'll be doing boards with AD1938 and AK4456/AK5534.
The goal is to have audio in - audio out and possibly spdif in - audio out. I'm waiting for I2S functionality to be "official".

Excellent! Hoping this goes smooth and makes it to reality.

 

[john61ct]

Yes, miniDSP put in a lot of "general preamp" functionality I personally do not want.

What I do need is DSP of LOTS of channels for overall system management

and DSPi can deliver that, two at a time

While I could never afford ANY of the all-in-one-box proprietary boxen.

So modularity is the key, I may want analog-only control of my main L/R three-way pair, and nothing at all needed for the rear surround pair

but LOTS of DSP management for midbass couplers and subs, bass management in general especially phase / timing management.

Of course if it's the main front channels that need delaying, then a couple more DSPi's are needed...

 

[Red_Red]

Yes, miniDSP put in a lot of "general preamp" functionality I personally do not want.

But that's also the principle of a DSP: to serve as a preamp in addition to its filtering/EQ capabilities.
All professional DSPs (Behringer and others) are a kind of digital preamp, as are the "MiniDSPs," but even simple DACs act as preamps with various external sources. In short, the purely analog preamp (inputs as well as outputs) is losing ground (very quickly) and is, in a way, destined to disappear...

 

[john61ct]

I am looking at using rPi 5 as a player node. How best to send its output direct to DSPi for when I do not want the Schiit SYN in between?

Could someone link to a good HowTo for noobs with a complete BoM list, ideally with purchase links?

 

[john61ct]

But that's also the principle of a DSP: to serve as a preamp in addition to its filtering/EQ capabilities.

I prefer modularity.

In short, the purely analog preamp (inputs as well as outputs) is losing ground (very quickly) and is, in a way, destined to disappear...

Even setting analog aside, if I used say a Wiim Ultra as preamp, I need a lot more bass management and DSP than it offers. I can output via USB already, or via S/PDIF in future, but need to SPLIT that output via intermediate devices in order to get six channels processed by DSPi's separately.

 

[Red_Red]

I prefer modularity.

Modularity you will have!

The question of volume management at the DSPi level or not has already been mentioned in the main thread a few weeks ago. In any case, the choice will be left to the end user. Troy is working incredibly hard to offer us a whole host of flexible options, to make the DSPi, as he says, "a Swiss Army knife."

But before considering advanced uses, we just need to wait a little while for development to progress further.

Be patient.

I am looking at using rPi 5 as a player node. How best to send its output direct to DSPi for when I do not want the Schiit SYN in between?

Could someone link to a good HowTo for noobs with a complete BoM list, ideally with purchase links?

It all depends on your Raspberry Pi 5's configuration :

- Without an expansion board (digital or analog) on your Raspberry Pi 5, the simplest way is to connect the DSPi via USB – which already works – or via I2S (once the firmware/console has been updated).

- With a digital expansion board: a Toslink cable.

- With an analog expansion board: an ADC + Toslink cable (but that's not the smartest solution).

 

[john61ct]

I never touched anything rPi, have bought nothing so far, so I am free to go with any / all of the above.

Let's say both Ethernet in for when I get the NAS going, and local storage of a few GB of FLAC files

both USB out and TOSlink will be useful to SYN

I don't mind buying from different sellers, want to avoid both tariff issues and giving money to Amazon.

Could someone link to a good HowTo for noobs with a complete BoM list, ideally with purchase links?

 

[somebodyelse]

I never touched anything rPi, have bought nothing so far, so I am free to go with any / all of the above.

Let's say both Ethernet in for when I get the NAS going, and local storage of a few GB of FLAC files

both USB out and TOSlink will be useful to SYN

I don't mind buying from different sellers, want to avoid both tariff issues and giving money to Amazon.

Unless you can be a lot more specific about what you need the Pi to do, it's going to be difficult to narrow down the options - and there are a LOT. There are a load of pre-built software options that essentially turn it into a streamer, each with their own take on what features it should have and how you should interact with it. The usual suspects are piCorePlayer, Volumio, Moode and Ropieee, but I can think of several more and still would have missed some options. They're an easy way to get started if you've never used a Pi before. I'm assuming you're not a linux user - if you are then you can treat the Pi as just another small linux box and install your preferred distro on there. There are a number of threads here about adding CamillaDSP to Ububtu and use it as a DSP system, active crossover etc.

 

[john61ct]

Sorry I was not clear, I am indeed a Linux guy, used to sysadmin server racks from CLI - in fact UNIX flavours before Linus was out of short pants.

I am NOT asking about software at all, but yes doing convolver processing not just playing.

BoM = hardware only, links to good sources

Just want to order everything complete all at once for those connections I listed, get reco's on HATs, accessories, power, whatever,

even cases which I'll order last.

I do have cables and SD cards.

 

[somebodyelse]

Still none the wiser what your requirements are, and without that it's hard to provide BoM. Things like wired or wireless networking, display requirements (if any), what inputs and outputs etc. It's not even clear whether the DSPi would be required since CamillaDSP is generally more capable (except maybe loudness?)

 

[john61ct]

It's not even clear whether the DSPi would be required since CamillaDSP is generally more capable (except maybe loudness?)

The point of the rPi 5 is testing the DSPi's

to be the stereo Renderer, the player hardware, feeding multiple DSPi out to the multi-channel amps.

Yes I will also be checking out CamillaDSP at some point - also full PC renderers + convolvers, also miniDSP boxen, also analog bass management - but none of that is being discussed ATM. I'm not asking for general advice on the overall testing project, that will evolve based on my results.


Here is what I wrote:

> I am looking at using rPi 5 as a player node. How best to send its output direct to DSPi

> Could someone link to a good HowTo for noobs with a complete BoM list, ideally with purchase links?

> Let's say both Ethernet in for when I get the NAS going, and local storage of a few GB of FLAC files

> both USB out and TOSlink will be useful to SYN

> I don't mind buying from different sellers, want to avoid both tariff issues and giving money to Amazon.


I have HDMI based monitors so leave out other display options. No wireless.

 

[somebodyelse]

Again really not helping narrow down the options. I'm out.

 

[Red_Red]

Could someone link to a good HowTo for noobs with a complete BoM list, ideally with purchase links?

In case it wasn't clear: We're not a concierge service!

We can point you in the right direction (if we can even understand what you really want, because, well, it's all over the place, one day it's this, another day it's that...), but we can't give you a ready-made shopping list.

Also, while we wait for DSPi development to progress further, you have plenty of time to research everything you've asked us about... And you can always create a dedicated thread with a diagram of your setup, explaining what you want to do with it, and if it's clear enough, people will probably reply!

I'm out too.