I think we see things from a similar perspective. I used to be outraged by the 5 digit prices of the high end AVPs, and wondered if you could achieve the same thing with a big pile of individual hardware and software elements, properly integrated together. I concluded it was possible but difficult. The components would add up to about £4000.
This line of thinking led to two things:
Firstly, an audio system could be considered to have a layered architecture, and separating the functions could be more efficient than an integrated solution.
Secondly, those high end AVPs actually did do more than cheaper processors. The DRC filtering was better, and they could also correct phase and speaker errors.
An AV system typically has the following key processes. These can all be performed in one box, but they can also be broken out:
- Dolby / DTS decoding
- Immersive rendering
- Amplitude correction
- Phase correction
- Reconstruction Filtering
- D A Conversion
- Gain control
- Buffering
- Amplification
I figured that an ideal audio system architecture would have one layer and one unit for each process or set of similar processes, each connected by non-proprietary, industry-standard interfaces, and each unit would be the optimum performance/cost solution for each function. Each layer could be exchanged or upgraded without upsetting the architecture, which would look something like this, and have the following advantages:
I started out looking for a cheaper solution to the megabucks processors, but learned this:
- Expensive processors do sound better than cheaper processors
- Digital decoder outputs do allow better amplitude linearity
- Both amplitude-frequency and phase-frequency linearity need equalisation
- A good system needs an open, scalable, non-proprietary architecture
- Layered architectures work effectively with complex systems
- One layer - one function - one unit - one input - one output
- Every unit is high performance, moderate cost and available off the shelf
- Each layer interfaces using open standards and connections
- A good preamp can help avoid the volume control bottleneck
- A good preamp can help improve DAC and power amp performance
- Good performance is needed, across the whole envelope, across every layer
My preferred solution is separate layers for playback, decode, process, convert, levels and amplification, and has the following advantages:
View attachment 525617
- High processing power
- Relatively low cost
- Compact and quiet
- Easy upgrading route
- Open, flexible, scalable, non-proprietary architecture
- Physical separation of playback & processing & conversion & amplification
- Opportunity to use DSP for speaker cross-overs
- Opportunity to use any source
- Opportunity to use any interfaces
- Opportunity to use any hardware
- Opportunity to use any software
- Opportunity to use any speakers
The open, flexible, scalable architecture matters, because it allows you to start small, add channels, upgrade or downgrade, and mitigate obsolescence.
You can see what works for you, without any heavy commitment to a single proprietary solution, which is a leap of faith if the sonic benefits are in any doubt.
EDIT 1: I think our difference is that I plan to do the DSP in a PC or Mac, and you plan to use an RPi (about which I have got no further than keen curiosity).
EDIT 2: The Tide16 does all of the above (except I believe digital domain volume control) in one box -
but should achieve similar cost & performance.