Multi-Channel, Multi-Amplifier Audio System Using Software Crossover and Multichannel-DAC

[dualazmak]

Edit: Please find here (on this thread) and here (remote independent thread post) the Hyperlink Index of this thread and some of my related posts in remote threads

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Edit on July 7, 2024
Just for your reference,,,
The latest system setup of my DSP-based multichannel multi-SP-driver multi-amplifier fully active audio rig, including updated startup/ignition sequences and shutdown sequences: as of June 26, 2024: #931
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I moved to Member Area to start this new thread after having very nice discussion and info exchange at;
https://www.audiosciencereview.com/...d-measurements-of-okto-dac8-8ch-dac-amp.7064/
where I joined on February 29, and participated on page 62 through 68, and sometimes thereafter.

In this new thread entitled "Multi-Channel, Multi-Amplifier Audio System Using Software Crossover and Multichannel-DAC", I would like to share and discuss any topic related to "software crossover" plus "multichannel-DAC" based multi-channel, multi-amplifier audio system.

Since I already found and confirmed that several "software crossover" solutions are also very much interesting and useful even for single DAC plus single amplifier system driving speaker units through LC (coils and capacitors) crossover network, any topic or discussion on "software crossover" for "single-DAC plus single amplifier" will be very much welcome.

Edited to add on April 28, 2020:
In this thread, I also would like to share and discuss these major issues always associating with Multi-Channel, Multi-Amplifier Audio System;
- Digital I/O for software crossover within PC
- Delay, latency and synchronization issues
- Phase issues
- Master volume and gain issues
As you may well aware, these issues are somewhat interdependent with each other.


Just to start this new thread, let me share with you all, who may have interests, my current on-going project using,
software crossover EKIO (LUPISOFT);
http://www.lupisoft.com/ekio/index.htm
Edited to add on May 26, 2020:
"EKIO uses IIR filters. The processing is done using a cascade of second order transposed direct form II biquad sections. Every calculation is done using 64 bit floating point numbers."
(please refer to post #139 and #140)

and 8-channel multichannel-DAC DAC8PRO (OKTO RESEARCH);
https://www.oktoresearch.com/dac8pro.htm
as illustrated in this scheme;

Please refer to my post #84 for the differences between YAMAHA NS-1000 and NS-1000M.

I have not yet fully decided the choices of the multi-amplifiers, i.e. Amplifier-1, -2, -3 and -4 in the above scheme.

While still waiting for the arrival of my DAC8PRO, I have fully tested the software crossover EKIO simulating the planned stereo 5-way 10-channel multi-channel audio system now with single DAC (OPPO SONICA DAC) plus single integrated amplifier (ACCUPHASE E-460).

In the following a few posts, I would like to share my current simulation trials with EKIO including the establishment of full ASIO I/O into and from EKIO.

You would please be patient and hold your posts, therefore, until I will write "welcome your posts" message hopefully within 2 - 3 days. Of course, your push of "Like" here will be always much appreciated....

 

[dualazmak]

Although I can write a lot about the reasons and pros of software crossover EKIO, I would like to reserve such discussion for future posts. Here, I just only suggest you all to visit EKIO's simple but informative web site and links there;
http://www.lupisoft.com/ekio/index.htm

Before sharing details of my establishment of full ASIO I/O routing with EKIO, let me first show you my current stereo 5-way 10-channel configurations of EKIO, designed for simulation of my targeting stereo 5-way 10-channel multi-amp system.

I believe that, to start trials with any crossover software (and hardware), we should use -12 dB/Oct slope BW (Butterworth) or LR (Linkwiz-Riley) filters because of rather flat crossover, flat total outputs, and also simple "phase" features. I just prefer LR filters, like shown below;

SL: Super Low, LO: Low, MD: Mid, HI: High, SH: Super High

SL: Super Low, LO: Low, MD: Mid, HI: High, SH: Super High

Using these typical crossover settings/configurations (with no delay setting here), we can allocate all of the 10 channels into single-DAC plus single-amplifier so that we may easily compare the total sound quality of EKIO vs. non-EKIO (non-crossover) sound.

We can also listen each of the 10 channels, and any combination of 10 channels, by using EKIO's Mute and/or Solo button for R-L balance check, phase check, gain check/control, etc. (Later on, I will share and discuss about "Super Audio Check CD" having very useful check tracks for ear listening tests and measurement microphone tests.)

We may change any of the crossover settings while EKIO is playing the sound/music given by JRiver MC, Roon, YouTube, Streaming Radio, etc.

In the next post, I will show details of the establishment of full ASIO I/O routing into/from EKIO using JRiver MC26 as music player on Windows 10 Pro 64bit OS.

 

[dwkdnvr]

I would advise against trying to run 2 different USB interfaces together. Or at least certainly do a lot of testing before committing to it. USB devices almost always run asynchronous these days, which means that each DAC has it's own master clock and there is a definite risk that these will drift out of sync over time.
In this specific case, I'd consider running a passive xover between the tweeter and super-tweeter resulting in a 4-way system which can run entirely from the Okto.

I hadn't seen Eiko before - might have to take a closer look. I suspect you could do this entirely in JRiver, but there is probably some value in factoring the xover out into an independent module.

 

[dualazmak]

I would advise against trying to run 2 different USB interfaces together. Or at least certainly do a lot of testing before committing to it. USB devices almost always run asynchronous these days, which means that each DAC has it's own master clock and there is a definite risk that these will drift out of sync over time.
In this specific case, I'd consider running a passive xover between the tweeter and super-tweeter resulting in a 4-way system which can run entirely from the Okto.

I hadn't seen Eiko before - might have to take a closer look. I suspect you could do this entirely in JRiver, but there is probably some value in factoring the xover out into an independent module.

I already got your point. This was also already discussed at;
https://www.audiosciencereview.com/...rements-of-okto-dac8-8ch-dac-amp.7064/page-65
https://www.audiosciencereview.com/...rements-of-okto-dac8-8ch-dac-amp.7064/page-66
and
https://www.audiosciencereview.com/...rements-of-okto-dac8-8ch-dac-amp.7064/page-67

You would please look very carefully the scheme, especially the speaker cable connection boards. I do not, will not, use the two USB lines simultaneously. The "OPPO Sonical DAC --> Accuphase E-460" is current conventional single-DAC single-amp operation, and after having DAC8PRO, I will use only another USB input to DAC8PRO for multi-amplifier system.

Since DAC8PRO is 8-channel DAC, I am planning to drive my sub-woofers by pre-out (line-out) RCA connections from the "Integrated Amplifier-1" in my scheme which will also drive woofers.

The SP cabling boards were prepared for easy switch back to my current, still very nice, single-DAC single-amp system;

 

[dualazmak]

In this specific case, I'd consider running a passive xover between the tweeter and super-tweeter resulting in a 4-way system which can run entirely from the Okto.

Yes, that is one possible option, I agree. I would like, however, first to avoid/eliminate any LC network and also attenuator for tweeter and super-tweeter.

Each of my sub-woofers have their own powerful amplifier, variable hi-cut, phase inversion switch and variable volume in it all controllable with remote IR controller. They are really heavy stuffs, but I can easily move them back and forth for precise delay tuning; I already placed Teflon sliding spacer under them. I will discuss later about the "delay" settings and measurements using REW-Wavelet analysis tool.

The unique physical alignment of the super tweeters, i.e. positioned under the woofers as described in my post here, is really one of the critical factors in my system in terms of the 3D sound perspective (3D sound stage).

Please refer to my post #84 for the differences between YAMAHA NS-1000 and NS-1000M.

 

[dualazmak]

Let me go back to the full ASIO I/O with EKIO.

Edit on October 29, 2021 adding one sentence:
I also summarized the contents of this post at here for easier understandings.

Since EKIO does not have its own ASIO driver (but DePhonica has it), we need to install these three before EKIO;

VB-Audio Virtual Cable;
VBCABLE_Driver_Pack43.zip (1.09 MB - OCT 2015), Donationware
https://www.vb-audio.com/Cable/index.htm

VB-Audio Hi-Fi CABLE & ASIO Bridge;
HiFiCableAsioBridgeSetup_v1007.zip (3.82 MB - MAR 2014) , Donationware
https://www.vb-audio.com/Cable/#DownloadASIOBridge

ASIO4ALL 2.14;
ASIO4ALL_2_14_English.exe (452 KB - MAY 2017)
http://www.asio4all.org/

I recommend you to install these three in this order, and just for sure, you may reboot your Windows 10 PC three times after each installation.

Then finally you need to install EKIO;
Ekio-1.0.6.0-install.exe (6.5MB, now Version 1.0.6.0, US$149 Net Price for one license)
http://www.lupisoft.com/ekio/

You can install EKIO in multiple PCs, and the purchased one license can activate only one PC's EKIO at one time.
Again, I recommend you to reboot your PC after installing EKIO.

VB-Audio Virtual Cable, VB-Audio Hi-Fi CABLE & ASIO Bridge and ASIO4ALL automatically start-up with Windows 10 boot, but it takes a little while, ca. 10 - 20 sec, to fully start-up and sit behind all the sound features. You should not, therefore, be in a hurry to start Roon, Jriver MC, etc., as well as EKIO before the complete sitting of VB-Audio Virtual Cable, VB-Audio Hi-Fi CABLE & ASIO Bridge and ASIO4ALL.

We should understand that ASIO4ALL is not only a universal ASIO driver but also a dominating software sitting in front of all the available ASIO and WDM audio devices.

Edit on October 29, 2021 adding this one additional diagram:

Like many other currently available crossover solutions, EKIO is a software crossover handling and processing all the sound in 24bit 192kHz, we should be careful enough to configure all the I/O in 24bit 192kHz. I will discuss the total sound quality of EKIO later on; here I just inform you that EKIO's sound quality is really nice even in 24bit 192kHz processing.

Now let me show you the full ASIO I/O establishment into/from EKIO with using JRiver MC26 as music player.

For your first trial, I would suggest to start and configure JRiver before the start-up of EKIO. Now you can select ASIO4ALL v2 (ASIO) driver as Audio Device for JRiver;

In the ... DSP & out put format (DSP Studio), all should be set in 192kHz;

and "Bitstreaming" should be "None" to make sure all the DSD music should be also down-sampled into 192 kHz 24bit.

Now you may start playing a music track, and ASIO4ALLv2 - Media Center26 icon appears in task bar, click it. You can see ASIO4ALL is dominating all the sound devices;

If not selected, just select only "VB-Audio Hi-Fi Cable" - Out: 8x8-384kHz, 24Bits. And for the first time, set the Latency Compesation and ASIO Buffer size as sown above. The change of the setting forces JRiver to stop playing, then you may again direct JRiver to play a music track; now the ASIO4ALL - Media Center panel is in all OK status as shown above.

Now in the backyard, VB-Audio Hi-Fi CABLE & ASIO Bridge is allocating/bridging the music signal into "VB-Audio Hi-Fi Cable in:" for EKIO's processing.

OK, while JRiver is playing a music track, you may start EKIO and open one of your EKIO configuration files, like the one example for my 10-channel simulation configuration, then go to Settings to select 192000 Sampling Rate and ASIO4ALL driver with 5120 buffer size;

Now the second ASIO4ALL icon of "ASIO4ALL v2 - Ekio" appears in task bar, click it;

Select only "VB Audio Hi-Fi Cable" - "In: 8x8-384kHz, 24Bits" and your DAC ASIO driver to which you would like to send the crossover channels, in this example I use "OPPO Sonica DAC USB AUDIO2.0 ASIO". For the first time, also set the Latency Compensation and ASIO Buffer Size as shown above. In order to reflect these ASIO4ALL setting for EKIO, you do need to go back to EKIO's "Settings", select "None" at the Driver selection, and then select "ASIO4ALL" again. Please check the ASIO4ALL -EKIO is OK now as shown in the above image.

Then we may go to Inputs/Outputs panel, where you can select VB-Audio Hi-Fi Cable 1 for INPUT-L channel, and VB-Audio Hi-Fi Cable 2 for INPUT-R channel;

Also now you may allocate each of the output channels into your DAC. In this example, I allocated all the channels into my OPPO SONICA DAC appearing as "DAC USB AUDIO 2.0 DAC1" for L channels, and "DAC USB AUDIO 2.0 DAC2" for R channels.

Go to the Routing panel to check and confirm the proper routing;

Finally, you would go back to the Inputs/Outputs panel, and please push the "STOPPED" button at the upper right corner to change into "PLAYING". Now you can see and hear that EKIO is playing by sending all the channels into your selected DAC;

You may see and check that ASIO BRIDGE is working in the backyard by clicking the ASIO BRIDGE icon in the task bar;

You may also go to the Windows Kernel Mixer, and check the all the devices in Sound-Off but still you can see and hear the music through EKIO without using Windows WASAPI and Kernel Mixer;

This is what I could establish full ASIO I/O into/from EKIO, and we can do essentially the same with Roon.

In case you would like to hear YouTube, streaming radio, etc. using your preferred web browser, just select Hi-Fi Cable Input as default audio device and configure it in 24bit 192kHz so that EKIO can process it; sorry about my Windows is in Japanese but it should be well understandable for you all;

I hope some of you would join me in trying EKIO, and share, as well as discuss, about it in this thread.

 

[Senior NEET Engineer]

Why not just use a A/V processor?

 

[dualazmak]

I also purchased one license of DePhonica;
https://dephonica.com/
but so far I could not find enough time to test it, especially the I/O routing. I know DePhonica provides its own ASIO driver for input of any sound into it, so the input routing should be easier than the that for EKIO. I would highly appreciate if some of you using DePhonica may join in this thread and share the configurations including how we can allocate output channels of DePhonica (max. 8 channels) into single DAC, and also into multichannel DAC like DAC8PRO.

Now I am very happy to invite any post fit for the thread title of "Multi-Channel, Multi-Amplifier Audio System Using Software Crossover and Multichannel-DAC".

 

[dualazmak]

Why not just use a A/V processor?

Just for my interest and enjoyment, I stick to pure Hi-Fi audio project aiming towards better sound quality over my current nice single-DAC plus single-amp Hi-Fi audio system. Many people would agree with me by posting their thoughts, enthusiasm and experiences with multi-channel multi-amp pure Hi-Fi audio system apart from A/V system, I hope.

 

[dualazmak]

As for the multi-amplifiers to be connected to DAC8PRO and my speaker units, I am also considering the possibilities of these "configurable, reasonable price digital multi-amplifiers" capable for 8-channel in one box;
https://www.kjfaudio.com/product/ma-01-flexible-amplifier/#slot-1
and
https://www.nordacoustics.co.uk/pro...w-custom-configurable-channel-amplifier-black
Hopefully, these topics will be also shared and discussed in this thread.

 

[dualazmak]

Just for your reference and info, current frequency (Fq) response of my system with single-DAC plus single-amp through LC network measured by ECM8000 microphone;

Please refer to my post #84 for the differences between YAMAHA NS-1000 and NS-1000M.

 

[dualazmak]

Consequently, in my project plan after the arrival of DAC8PRO for multi-channel multi-amp system of;

my tentative channel allocation plan would be;

The main reason for still keeping super low SL-L and SL-R channels here is that, in some great but rather old music sources ripped from CD or digitized from LP records, unpleasant small volume super low Fq noises around 20 - 35Hz caused by hall air conditioning or by LP records' bending are deteriorating the total sound quality which can be mute off by the Mute buttons of SL-L and SL-R channel panels.

Typical example of such a case is John William's great and wonderful guitar performance of guitar music by Augustin Barrios "From the Jungles of Paraguay: John Williams Plays Barrios";
https://www.amazon.com/Jungles-Para...s=John+Williams+barrios&qid=1586515533&sr=8-1
really wonderful performance and excellent recording quality, but unfortunately containing unpleasant low Fq air conditioning noises.

Except for these very rare cases, of course I definitely need the high quality super low sound around 15 - 45 Hz covered by SL-L and SL-R (and partly by LO-L and LO-R).

 

[maxxevv]

It should even more interesting once you get everything hooked up !

 

[dualazmak]

It should even more interesting once you get everything hooked up !

Yes, I fully agree with you. Hopefully I will receive my DAC8PRO in 3 - 4 weeks if it would come through airline delivery, but the domestic logistics here in Japan looks somewhat affected by current COVID-19 pandemic/epidemic. It should be quite OK for me to wait for a while.... as I can further test and simulate EKIO and others, as well as I can spend time for web research and investigation on possible multi-amplifiers.

Now I am very much interested in NORD Acoustics' configurable 8-channel amplifier;
https://www.nordacoustics.co.uk/pro...w-custom-configurable-channel-amplifier-black
for my project, with
Channels 1-2: NC252MP (2x250W 4Ohm, 2x200W 8Ohm）
Channels 3-4: NC122MP (2x125W 4Ohm, 2x75W 8Ohm）
Channels 5-6: NC122MP (2x125W 4Ohm, 2x75W 8Ohm）
Channels 7-8: NC122MP (2x125W 4Ohm, 2x75W 8Ohm）

and now gathering various info on Hypex Ncore amp modules, NCxxxMP series.

 

[dualazmak]

Although the contents of following a few posts by myself would be somewhat overlapped with my dispersed posts on page 62 - 67 of;
https://www.nordacoustics.co.uk/pro...w-custom-configurable-channel-amplifier-black
I hope it should be allowed and worthwhile to summarize again here...

 

[dualazmak]

I checked frequency (Fq) response of EKIO's multichannel outputs in line level (i.e. without using amp and speakers);

 

[dualazmak]

Then I checked "cleanliness" of EKIO's outputs in line level using REW-Wavelet analysis;

 

[dualazmak]

After the arrival of DAC8PRO, I would like to use, if needed, the group delay function of EKIO. I should check, therefore, the capabilities and accuracy of EKIO's delay control as well as sensitivity of REW-Wavelet analysis for delay measurements. I could confirm these in line level;

 

[dualazmak]

Then I measured the real EKIO sound with my current single-amp system in my listening environment using BHERINGER ECM8000 measurement microphone;

 

[dualazmak]

I also measured "delay features" of the real EKIO sound using REW-Wavelt analysis;