High end all digital dsp crossover ? - Page 8 - diyAudio
Go Back   Home > Forums > Source & Line > Digital Line Level

Digital Line Level DACs, Digital Crossovers, Equalizers, etc.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 31st October 2012, 12:26 AM   #71
diyAudio Member
 
Join Date: Jan 2005
Location: Sweden
Quote:
Originally Posted by Tordenguden View Post
Might one ask what the rest of your system consist of - and what your reference and goal is. Or is it only the theoretically optimal DSP that you want to discuss?
Ok lets go then, source first:
Mac mini/audirvana or Sony scd 777es-with separate dac.
Turntable, a Verdier rip-of and tube riaa "Tubecad".
Preamp also tube based from "Broskie" with Stevens & Billington
tvc's for volume attenuation.
Speakers are 6 feet long ribbons of own construction 95bd 350-20000hz
12 8inch woofers (Seas) / channel 30-350.
Tapped horns for subs (Beyma 12L60).
Crossover 2order, passive for the ribbons (Duelund VSF cu) and dsp/active
for the woofers and subs (4th order).

I will have to leave goal and reference for tomorrow, need some sleep now.
  Reply With Quote
Old 31st October 2012, 07:48 AM   #72
diyAudio Member
 
Join Date: Feb 2011
Fair enough - sleep is important

Reason for asking is to get an idear of what you are seeking. I have listened to alot of different system with both passive, FIR and IIR filters. And my experience is that it all can work to a high degree of realism. But the active solution gives a more flexible way of controlling precisely what you want the system to do.
I use active DSP filtering (IIR) for all drivers in my system, and heard others use it for their systems as well, also ribbons and panels, with no problems.
Does my memory serve me right - or is it you that are seeking a DSP with enough dealy, to meet your large horn-subs?
  Reply With Quote
Old 31st October 2012, 08:50 AM   #73
diyAudio Member
 
Join Date: Jan 2005
Location: Sweden
Yes, that's me.
Forgot the amps:
There will be a pair of SET monoblocks ready in a few weeks (C3m/kr300b xls/LL1623) to drive the ribbons. I'm using abletec alc0300 for all other sections.

And for now this is a theoretical disscusion that hopefully will inspier someone more qualified to actually build something.
The flexibility of "Chaparks" filter is what brougth the idea to life.
  Reply With Quote
Old 31st October 2012, 12:44 PM   #74
diyAudio Member
 
Join Date: Jan 2008
Quote:
Originally Posted by twest820 View Post
For example, I've gone through that exercise with CS4272s (one of Cirrus's -100dB/114dB DNR parts) and amps ranging from 0dB to 28dB gain (all of comparable THD, slew rate, and so on) and the results were kind of surprising. In the test configuration the ~27dB gain amps measured around -50dB acoustic THD for conversational listenling levels due to hitting the DAC floor. Switching to amps with around 10dB gain resolved the speakers -55 to -60dB THD but the ABX results from critical listening were 100% for the lower gain amps. Not by a small margin either; it was more like "why are we bothering to test this?"
DSP is math, DSP chips are calculators built for convolution. Data in data out. Latency is dependent on sample rate, filter length, and specifics of how convolution is calculated, and limitations of how calculation may be performed.

For example, PC based convolution with Sourceforge Convolver for audio has partitioning that allows filter to broken down into blocks resulting in dividing down pass through latency. Throughput is optimized based on computational processing power and balancing partition number v filter length. Similar parallels exist with DSP chips, taking advantage of long word lengths and parallelism of architecture. In the end it is all about multiply, add, and carry. Getting output data to a bank of DACs is wheel that has been spinning nicely for quite some time.

Convolver on inexpensive PC can do 65k filter on 8ch at faster than real time using 32bit floating point math. Way more than enough resolution for 24bit integer sources.

24bit integer dynamic range exceeds noise floor of a resistor at room temperature.

Quote:
In the test configuration the ~27dB gain amps measured around -50dB acoustic THD for conversational listenling levels due to hitting the DAC floor.
This is nonsense. Drivers and measurement setup are limiting factors here. Floor of DAC must be measured at its outputs.

Regards,

Andrew
  Reply With Quote
Old 3rd November 2012, 09:15 PM   #75
diyAudio Member
 
Join Date: Jan 2005
Location: Sweden
After some conversation with "Chapark" (thanks again) it has come to my
attention that the master clock should be included in the dsp package. That
was my interpretation anyway. Of cource this should also be of the best
possible standard.
  Reply With Quote
Old 3rd November 2012, 09:29 PM   #76
diyAudio Member
 
Join Date: Jan 2008
End user DACs should be of high enough quality to regenerate low jitter clock from any relatively decent clock. Likewise board should be able to work with clock of any digital source.

Regards,

Andrew
  Reply With Quote
Old 3rd November 2012, 10:19 PM   #77
diyAudio Member
 
Join Date: Jan 2005
Location: Sweden
If someone with the knowledge time and drive to complete something like this is hesitant thinking that no one would be interested in buying such a device I beg to differ.
"Chapark" is charging 375usd incl chipping for his device and I belive that's cheap. I would gladly pay two or maybe even three times that for this (for now) imaginary "High end device".
And there is no need to supply dac's,analog outputs, volumecontrol, connectors (other than u.fl) and so on. A decent adc might actually be what's most interessting if something actually should be included (there are not many external to chose from).

Now don't read me wrong here I'm not dissing "Chaparks" work at all and I will be among the first in line to get my hands on one of his devices. And maybe he will prove me wrong and then there is no real need for this project. On the other hand there will always be evolution and it's fun to search for the next "pot of gold".

I would be very surprised if me and "qusp" where the only two ones in the whole world that think that this is an interessting idea worth to spend a few bucks on.

I'm thinking something quite simular to "Loriens" Wave IO in build quality (it's a piece of art actually ).

That was my Saturday night ramblings
  Reply With Quote
Old 3rd November 2012, 10:47 PM   #78
TNT is offline TNT  Sweden
diyAudio Member
 
TNT's Avatar
 
Join Date: Apr 2003
Location: Sweden
"The idea is to supply ones own digital reciver (usb), favorite
dac's and analog output stages."

The "DSP" is not the challenge. Nor is the software. Whats left, taking Your prerequisites into account, is oscillator, clock and clock distribution.

Is it the clocks your are not satisfied with in Chaparks XO? Or is it to low cost ?
  Reply With Quote
Old 3rd November 2012, 11:39 PM   #79
diyAudio Member
 
Join Date: Jan 2005
Location: Sweden
I actually have no idea how "Chaparks" XO is put together other than two
parts, he has been quite secretive with how it's put together (and thats
actually allright by me even if I'm a little bit curious).

So clock and other stuff is still a bit of a mystery.

Yes maybe I'm just looking for the absolute best parts available combined into
an all digital dsp with a build quality of "Loriens" Wave IO

Last edited by dahlberg; 3rd November 2012 at 11:41 PM.
  Reply With Quote
Old 4th November 2012, 12:07 AM   #80
diyAudio Member
 
Join Date: Jun 2009
Quote:
Originally Posted by TNT View Post
"The idea is to supply ones own digital reciver (usb), favorite
dac's and analog output stages."

The "DSP" is not the challenge. Nor is the software. Whats left, taking Your prerequisites into account, is oscillator, clock and clock distribution.

Is it the clocks your are not satisfied with in Chaparks XO? Or is it to low cost ?
I don't see too many here building dsp boards and writing dsp software do you ?? DAC boards are a dime a dozen on ebay
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
DSP StudioX: active/digital crossover simulator with features... Under construction. s3tup PC Based 11 22nd November 2012 06:03 PM
High End digital 50W amplifier board sunlight009 Vendor's Bazaar 0 19th March 2012 03:12 AM
High quality DSP crossover setup on a budget? Thunau Multi-Way 2 2nd November 2007 10:55 AM
A high-end digital amplifier for everyone DAXgroup Digital Source 82 30th June 2007 03:16 PM
High end digital cable MichaelJHuman Everything Else 1 30th August 2005 02:41 AM


New To Site? Need Help?

All times are GMT. The time now is 05:27 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2