• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

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

Not saying you blindly applied textbook filters (I have no idea how you arrived at that layout) but I think that is the point being made.

The "you" in your above sentence is pointing myself, right?

This thread is a kind of lengthy BLOGS on the progress of my PC-DSP-Based multichannel multi-SP-driver multi-amplifier fully active audio (audio-visual) project.
You would 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.

In order to properly respond to your above worry of "(I have no idea how you arrived at that layout)", I am sorry, but it would be inevitable to ask your precious time for your understandings on the prehistoric story and very early "history" (until the arrival of OKTO DAC8PRO) of this project.

I would highly appreciate, therefore, if you could spare your precious time for a while to read through page 1 to page 5 (posts #1 dated April 9 of 2020 through around #100 dated May 10, 2020); after your kind read, you will have idea how I arrived at the latest system setup (as of June 26, 2024) shared in my post #931 dated July 7, 2024.


By the way, as for very general discussion/guidance on sub-woofer to woofer crossover, I recently wrote this post #3 responding to @Smoey22's inquiry on his new thread.
 
Last edited:
Hello, I’d like to point out that here on this forum, we’re not audio engineering students but regular folks, often pressed for time and not keen on reading through numerous links that lead to even more references. I think even AI would understand and provide a straightforward answer to a simple question: what principles, specifically which acoustic filters, did you use when designing your four-way speaker system? Please, no links to other references. I know it might seem unreasonable, but could you kindly repeat the key points you’ve already mentioned? Please respond in no more than 100 sentences and under 2000 words.
 
Last edited:
In order to properly respond to your above worry of "(I have no idea how you arrived at that layout)", I am sorry, but it would be inevitable to ask your precious time for your understandings on the prehistoric story and very early "history" (until the arrival of OKTO DAC8PRO) of this project.
Yes I mean you as the designer. The part in bold was just to guard against my words being read as if you had just applied such things in that fashion. I haven't read in detail because it's not my question so I wasn't looking for an answer, I was just observing that the other poster seemed to be asking a different question to that answered.
 
I know it might seem unreasonable, but could you kindly repeat the key points you’ve already mentioned?

OK, let me try as follows in 7 sentences, with ca. 350 words.


Prior to starting this project, I already had and much enjoyed really excellent passive 3-way SP YAMAHA NS-1000 plus L&R sub-woofers YAMAHA YST-SW1000 and L&R super-tweeters FOSTEX T925A, all driven and fed by a nice integrated amplifier ACCUPHASE E-460; those were my pre-project passive audio setup.

After receiving OKTO DAC8PRO, I fully eliminated the passive LCR XO network and attenuators from NS-1000 to make it fully active 3-way, i.e. each of the three SP drivers (as well as super-tweeters FOSTEX T925A) is driven directly and dedicatedly by each of the four amplifiers; sub-woofer YST-SW1000 has its own powerful amplifier in it.

The four HiFi integrated amplifiers have been very carefully evaluated and selected according to my policy "right-person-in-right-place" on amplifier exploration; all candidate amplifiers were actually evaluated in my audio setup at my listening room in my room acoustic environment.

I essentially nicely simulated and further optimized the YAMAHA's almost miracle passive (BW, 2nd-order) LCR XO network by active PC-based DSP software EKIO's 2nd-order LR filters at 50 Hz, 500Hz, 6kHz (plus passive 1st-order capacitor filter at ca. 8.8 kHz for super-tweeter); furthermore, the super-tweeters, directly driven by dedicated amplifier, were set in wide-3D reflective-dispersion-configuration using random-surface hard heavy thick glass material.

As the result of my rather long mountain climbing-type audio exploration project, I could achieve substantially better total sound quality in DSP-based multichannel multi-SP-driver multi-amplifier fully active audio setup compared to my pre-project passive audio setup, together with optimized XO configuration with sub-woofer and with super-tweeter, in my listening acoustic environment. You can get "at-a-glance" understandings on my latest system setup by looking at a few diagrams and photos I have recently shared on July 7, 2024; one diagram or photo would worth more than 1,000 words, I believe.

During the course of my audio endeavors, I have been using my own consistent "Audio Sampler/Reference Music Playlist" consists of 60 tracks which was/is widely shared with friends and colleagues within ASR Forum.

If you would be interested in each of the details in this audio project, I will be more than happy to give you the link(s) to my relevant post(s); for your further convenience, I also prepared Hyperlink Index to this lengthy BLOG-type thread.
 
Last edited:
OK, let me try as follows in 7 sentences, with ca. 350 words.


Prior to starting this project, I already had and much enjoyed really excellent passive 3-way SP YAMAHA NS-1000 plus L&R sub-woofers YAMAHA YST-SW1000 and L&R super-tweeters FOSTEX T925A, all driven and fed by a nice integrated amplifier ACCUPHASE E-460; those were my pre-project passive audio setup.

After receiving OKTO DAC8PRO, I fully eliminated the passive LCR XO network and attenuators from NS-1000 to make it fully active 3-way, i.e. each of the three SP drivers (as well as super-tweeters FOSTEX T925A) is driven directly and dedicatedly by each of the four amplifiers; sub-woofer YST-SW1000 has its own powerful amplifier in it.

The four HiFi integrated amplifiers have been very carefully evaluated and selected according to my policy "right-person-in-right-place" on amplifier exploration; all candidate amplifiers were actually evaluated in my audio setup at my listening room in my room acoustic environment.

I essentially nicely simulated and further optimized the YAMAHA's almost miracle passive (BW, 2nd-order) LCR XO network by active PC-based DSP software EKIO's 2nd-order LR filters at 50 Hz, 500Hz, 6kHz (plus passive 1st-order capacitor filter at ca. 8.8 kHz for super-tweeter); furthermore, the super-tweeters, directly driven by dedicated amplifier, were set in wide-3D reflective-dispersion-configuration using random-surface hard heavy thick glass material.

As the result of my rather long mountain climbing-type audio exploration project, I could achieve substantially better total sound quality in DSP-based multichannel multi-SP-driver multi-amplifier fully active audio setup compared to my pre-project passive audio setup, together with optimized XO configuration with sub-woofer and with super-tweeter, in my listening acoustic environment. You can get "at-a-glance" understandings on my latest system setup by looking at a few diagrams and photos I have recently shared on July 7, 2024; one diagram or photo would worth more than 1,000 words, I believe.

During the course of my audio endeavors, I have been using my own consistent "Audio Sampler/Reference Music Playlist" consists of 60 tracks which was/is widely shared with friends and colleagues within ASR Forum.

If you would be interested in each of the details in this audio project, I will be more than happy to give you the link(s) to my relevant post(s); for your further convenience, I also prepared Hyperlink Index to this lengthy BLOG-type thread.
Ok, from your post I gather that your concept, based on your experience with the passive and original crossover of the NS1000, was implemented in such a way that by adjusting the DSP parameters – namely frequency and filter slope – you kept tweaking until you achieved a similar effect. This is one way to do it, but there are other methods as well. If you're satisfied with the outcome of your work, then so be it. However, if you'd like to see what I or another colleague might come up with, I suggest that you take measurements of each speaker using RWE without the crossover but with those capacitors protecting the beryllium drivers. Just describe the distance at which the measurement was taken and send it as a zipped file (*.ZIP) as evidence.
P.S.
You can omit the 22 ohm resistor, no one needs it here.
 
Last edited:
I suggest that you take measurements of each speaker using RWE without the crossover but with those capacitors protecting the beryllium drivers.
I checked Fq-SPL curves with and without (before and after) protection capacitors in SP-high-level signals in my post #402;
WS002120.JPG


WS002119.JPG


WS002128.JPG


WS002127.JPG


Please note that I use integrated amplifiers with which flexible on-the-fly (while playing/listening to music) relative gain control can be done; for example, in super-tweeter sound, i.e. ca. 8kHz to 20 kHz, the Fq-SPL measurement was done in SP-high-level signal and in room air sound at my listening position in my post #485;
WS002907.JPG


WS002904.JPG

I use measurement microphone BEHRINGER ECM8000 which was specially selected, and it was cross-calibrated with strictly-calibrated EARTHWORK M50 measurement microphone; my ECM8000 has acceptably flat response throughout 10 Hz to 22 kHz within +0.7 dB/-0.5 dB from flat 0.0 dB, i.e. within 1.2 dB in the whole (ref. #831).

You can omit the 22 ohm resistor, no one needs it here.
In my specific set up, the 22 Ohm fine-tuning parallel resistors give very-slightly better sound quality (low distortion) maybe due to forcing the amplifiers working a little above the zero-cross level; we have already discussed a lot on this;
- In depth insights on SP attenuators and their elimination in multichannel system: #248, #251, #99(remote thread), #100(remote thread), #101(remote thread)
You need to read carefully especially my post #248.

During the course of my amplifier selection exploration, I always compared/confirmed the total sound quality with/without the 22 Ohm fine-tuning resistors as well as with/without the protection capacitors, for example using the on-off signal path shown in my post #258;
WS00007834.JPG
 
Last edited:
Hello @LSPhil,

I assume that I have already cordially responded to your inquiries on my project, and I think it would be better to end-up our communication at least on background and my implementation "concept/policy"; these might be redundant (or well known and already fully understandable) to many people frequently visiting and following this thread.

I believe now it would be your turn to kindly respond to my specific inquiry/request #221 together with your diagrams and/or photos, on that my remote thread.;)


BTW, I essentially agree with your subjective comment shared in your post here which can be read as; "One is never done with DIY projects. But one thing is certain: combinations with large domes are acoustically really sexy."
 
Last edited:
I understand, you want me to leave you alone. If you don't want or can't answer the questions directly, there must be good reasons for it, and you don't even need to share them with us/me. Best of luck and stay healthy.
 
I understand, you want me to leave you alone. If you don't want or can't answer the questions directly, there must be good reasons for it, and you don't even need to share them with us/me. Best of luck and stay healthy.
Thank you, the same to you too!

I would like to continue our invaluable communication/discussion, however, on the remote thread which would be also much worthwhile to other people within ASR. ;)

I am not alone here on this project thread; you can find list of major 49 followers at the bottom of my very first post, and number of visits/views on this thread exceeded 305K times as of today.
 
Last edited:
As I just wrote here on the remote thread...

I received an important big news from OKTO Research today, "OKTO Reseach Autumn 2024 Newsletter".

In response to my and our intensive requests (I believe so), OKTO is announcing support for parallel operation of DAC8PRO (demonstration of three DAC8PRO), combined into a single USB device!:D

They said; "This setup delivers 24 channels of audio, supporting up to 192kHz/32-bit resolution. The clocks are synchronized via AES/EBU, ensuring zero clock drift and phase shift, while volume control is unified across all units and fully managed from the master DAC. This feature opens up many possibilities for home cinema and multichannel audio setups and will be included in the upcoming firmware release."

Since it looks the detailed information is still not yet available on OKTO's web site, I dare not to copy paste all of the contents of the Newsletter here in my post on this thread (including the diagram screen shot of the coming aggregate/combined device settings for three of DAC8PRO where the first DAC8PRO serves as master clock via AES/EBU enabling 24-Ch ins and 24-Ch outs).
 
Last edited:
An absolutely stunning setup, indeed.
Welcome onboard on this multichannel multi-SP-driver multi-amplifier audio project thread!
I assume and hope you have visited my lengthy post #931 sharing the latest system setup, have you?
 
Last edited:
I have, but a bit superficially to be honest, because I would need hours of study in order to able to comprehend all the complexities and arcana of that extraordinary system. It so happens I visited Japan with my family earlier this year and it was love at first sight and a truly unforgettable experience. A wonderful country, with a passion for excellence, in all spheres of life.
 
Back
Top Bottom