1 (edited by grizaudio 2020-11-21 13:23:11)

Topic: RME ADI-2 DAC user looking to build an active speaker (DSP Crossover)

This might not be in the most appropriate thread and I apologise.

I currently use an RME ADI-2 DAC FS as a digital preamp and D/A converter for my RPI4, running Ropieee XL. My system utilises the ADI’s on board PEQ and DSP to equalise room acoustic effects. I find the on board PEQ of excellent quality. Its dead silent, which has not been my experience with other alternate consumer “small” DSP products. 

ATM I am investigating designing/making an active DSP speaker. Either a 2way Econowave or maybe even a three way.

I am so happy with the RME ADI 2's DSP performance, sound quality, and dead silent operation, that I am considering using a USB 2.0 to multi channel RME interface, with software crossovers via Roon (PEQ and convolution filters).

To my knowledge RME doesn’t offer a DSP speaker manager (Am I wrong? this would be awesome), so my thinking is an RME interface using Roon for filters is the next best thing.

Setup requirements are:
-    Physical Master volume for easy in room volume control
-    Roon volume control via hardware mixer would be nice
-    At least 6 channels of output
-    At least as good or better performance/sound quality V’s RME ADI 2
-    Native Linux and windows support, standard class 2 drivers for 6-8 channels
-    Asio support
-    As cost effective as possible

In the same vain as:
https://www.oktoresearch.com/dac8pro.htm

1. What would forum users suggest is the best RME product for this application?
From my googling it appears the Fireface UC/UCX is the cheapest match.
2. Would the DA conversion be on par with the RME ADI 2?
3. Does anyone have any experience with a similar setup?

Thanks for your time.

Re: RME ADI-2 DAC user looking to build an active speaker (DSP Crossover)

It can be done using RME's "Totalmix" software with a Totalmix compatible RME interface.
Will it be easy and flexible to use? No!
Use will be locked to the PC the Totalmix is running on.


I'd have a look in the Pro-Audio market for dedicated digital X-overs, or multichannel amp solutions with built in x-overs.

E.g. I'm running a pair of Electro-Voice Sentry III through an active X-over with 2 stereo power amps.
Once set up it's "Plug And Play" with any source I like.

3 (edited by grizaudio 2020-11-22 07:54:14)

Re: RME ADI-2 DAC user looking to build an active speaker (DSP Crossover)

KaiS wrote:

It can be done using RME's "Totalmix" software with a Totalmix compatible RME interface.
Will it be easy and flexible to use? No!
Use will be locked to the PC the Totalmix is running on.


I'd have a look in the Pro-Audio market for dedicated digital X-overs, or multichannel amp solutions with built in x-overs.

E.g. I'm running a pair of Electro-Voice Sentry III through an active X-over with 2 stereo power amps.
Once set up it's "Plug And Play" with any source I like.

Thanks

I have considered using pro DSP, but noise/hiss can be an issue with some pro DSP/crossover gear.
With wholesale access to most major pro brands (Powersoft, Biamp, Symetrix, Qsys etc) this is not a limitation for me. 
My concern is creating a transparent and idle/self noise free solution.
Roon is my only source.

My opinion/thinking is a multiway USB dac using high quality amplifiers will provide a better SINAD, lower self noise and improved sound quality. There are users on the Roon forum doing this without issue. They typical use Focusrite and Motu interfaces.

ATM, I use a Firstwatt F7, connected to my RME (as DAC/PRE). At full volume, on 92db drivers I have absolutely no self noise/hiss. I would like to maintain this performance. 

I have explored Pro gear, and considered using DSP amps, and hardware based digital processing.
But my experience over many years is these products are not optimised for noise/hiss and nearfield listening.
DSP multiway amplifiers are also typically class D, and although I have nothing against class D, its not my favourite choice.

I would have thought any RME USB interface would be suitable, I.e. the Fireface UXC (which is class compliant).
Many users are using Motu8, Focusrite units without issue.

4 (edited by pschelbert 2020-11-22 00:27:17)

Re: RME ADI-2 DAC user looking to build an active speaker (DSP Crossover)

Hi

I assume
-you want to have Stereo and 2...4way =4...8 channels
-analog output (with digital ouptut into digital amps its another story)

I use for this RME UFX or UFX II, both are 12xAD and 12xDA.

The way I run it:

HD (flac)-PC with Jriver-acourateconvolver (crossover 2x4way+2xStereo headphones)-multichannel poweramp-speakerchassis

acourateconvolver is a FIR multichannel filter, crossover, see: www.audiovero.com

Note: crossover can be done in JRiver (IIR and FIR), but acourateconvolver is better.

Roon: may be the crossover can be done in Roon, but I dont know Roon.


Although ADI-2 pro is slightly better than RME UFX, UFX II (measured values), ADI-2 Pro is as far as I understand primarly a stereo device whereas the UFX and UFX II are multichannel devices.

I have no noise or hiss problems of the setup itself. The musicfiles are the problem smile

P.S. I used to have Motu (Motu823mkII hybrid), works as well however I was not happy with the software stability of the drivers and the audio quality, Focusrite I do not know personally.

Peter

5 (edited by grizaudio 2020-11-22 01:02:38)

Re: RME ADI-2 DAC user looking to build an active speaker (DSP Crossover)

Great to know.
I suspect any USB interface with adequate outputs will work fine.
But as you highlighted, software stability is important.

Roon can perform all crossover duties.
It offers up to 8 channels of DSP, with PEQ, and convolution filters in the time domain.

Another piece of software I am considering is:
https://juicehifi.com/

I plan to utilise Smaart to develop my crossovers, room correction, and align for time.

Do you know if the Fireface UXC run's the latest RME Dac technology?
Is it AKM based?

Thanks for your feedback.

6 (edited by KaiS 2020-11-22 02:49:33)

Re: RME ADI-2 DAC user looking to build an active speaker (DSP Crossover)

Noise is always a sign of a wrong gain structure.

If the final stage - power amp + speaker - has too much gain, the DSP and DAC stages work on too low level and do not use their full S/N ratio potential.

Every current multichannel RME interface has a S/N ratio of 30 dB beyond CD quality, which can be considered noise-free.

Input level controls or passive attenuators on the power amps are the tools to adapt the available dynamic range to the listening level demands and dynamic range of speakers.

7 (edited by grizaudio 2020-11-22 04:48:45)

Re: RME ADI-2 DAC user looking to build an active speaker (DSP Crossover)

KaiS wrote:

Noise is always a sign of a wrong gain structure.

If the final stage - power amp + speaker - has too much gain, the DSP and DAC stages work on too low level and do not use their full S/N ratio potential.

Every current multichannel RME interface has a S/N ratio of 30 dB beyond CD quality, which can be considered noise-free.

Input level controls or passive attenuators on the power amps are the tools to adapt the available dynamic range to the listening level demands and dynamic range of speakers.


I agree with this in theory, and I understand gain structure.

My current F7 has 14db gain, and I would be looking to match this with additional amplifiers.. Ie pro amps with adjustable gain, or minimal gain options like Purifis 1ET400a, etc.

But.... many amplifiers, DSPs and active speakers for that matter have self noise.
Genelec actually provide this SPL measurement.

8 (edited by KaiS 2020-11-22 14:46:28)

Re: RME ADI-2 DAC user looking to build an active speaker (DSP Crossover)

Some figures to bring the above into relationship:

Everything has a self noise, even a short piece of wire - albeit this one is almost impossible to measure and absolute inaudible by multiple magnitudes.


With current RME products you have a dynamic range of about 120dB.
This range can be spent to 0 - 120 dBSPL, or 20 - 140 dBSPL, or whatever you like.

0 dBSPL equals the threshold of hearing for a young, perfectly healthy ear.
Practically the threshold of hearing is very individual, and can vary by 40dB and more from person to person.

120dBSPL is the so called "threshold of pain" and permanently damages the hearing apparatus within minutes of exposure.

A typical living room in a quiet environment has a "self noise" of at least 20-30 dBSPL.

9 (edited by pschelbert 2020-11-23 00:18:34)

Re: RME ADI-2 DAC user looking to build an active speaker (DSP Crossover)

grizaudio wrote:

Great to know.
I suspect any USB interface with adequate outputs will work fine.
But as you highlighted, software stability is important.

Roon can perform all crossover duties.
It offers up to 8 channels of DSP, with PEQ, and convolution filters in the time domain.

Another piece of software I am considering is:
https://juicehifi.com/

I plan to utilise Smaart to develop my crossovers, room correction, and align for time.

Do you know if the Fireface UXC run's the latest RME Dac technology?
Is it AKM based?

Thanks for your feedback.

Hi

I didn't try nor with Roon nor with Audiolense.
I tried only with Jriver, works but not flexible and acourateconvolver which I use now.
For FIR design and also measurement, room-correction I use acourate-pro.

UCX: I don't know about the chips inside. What I know form advertisment of RME that the UFX II uses AKM chips.

I can say UFX and UFX II are way beyond audible noise. UCX I heard at a friends house, also a fine product if you don't need  the additional channels which UFX and UFX II provide.
My experience: you can never have too much channels smile

Peter

Re: RME ADI-2 DAC user looking to build an active speaker (DSP Crossover)

Following, i too am interested in using my ADI-2 Pro for either an active 2/3 way speaker build
https://community.klipsch.com/index.php … ntry-horn/
grizaudio - keep us up to to date on what you end up doing