diy tacT ambiophonic processor on the cheap. Can it be done?

[durwood]

Originally Posted by Elias

This can be done perfectly with simple analog electronics with a few opams!

- Elias

Yep, opamps can be used to invert, sum, filter. Adjustable all pass filter for delay for example.

In the car audio world, Audiocontrol made an analog 2 channel processor that I believe is fairly close to this concept (stereo widening). It was called an ESP-2. They also had an ESP-3 that added a center channel which would not be needed. This was a long time ago. The patent was issued to someone who later started SRS labs if memory serves me right.

Here are a couple places to start:
http://www.google.com/patents/about?...J&dq=4,748,669
http://www.google.com/patents/about?...J&dq=5,892,830

[poldus]

I own a Hughes Sound Retrieval box that´s probably similar in concept to those patents. What they do is different to this.They are not recursive ambiophonics crosstalk cancellation. In RACE the added cancelling signals are have to be cancelled themselves ad infinitum so to speak. Hence the [I]recursive[I]. I figure that would take a fairly large number of opamps to achieve. For some reason it has never been implemented in the past until software power has increased exponentially.

[gooki]

Originally Posted by durwood

Another option...Maybe someone should ask the minidsp guys nicely if they would develop an ambio plugin.

Already asked - not possible at this stage.

[durwood]

Originally Posted by gooki

Already asked - not possible at this stage.

Bummer, it shouldn't be that difficult to implement but they probably have other priorities...maybe if or when it's slower for them.

Originally Posted by poldus

I own a Hughes Sound Retrieval box that´s probably similar in concept to those patents. What they do is different to this.They are not recursive ambiophonics crosstalk cancellation. In RACE the added cancelling signals are have to be cancelled themselves ad infinitum so to speak. Hence the [I]recursive[I]. I figure that would take a fairly large number of opamps to achieve. For some reason it has never been implemented in the past until software power has increased exponentially.

The recursion is too much for me. I prefer the simple method shown at this link

electro-music.com :: View topic - Mosc's Ambio VST

and with the newest version give you more degrees of adjustment for matching your tastes, including recursion.

electro-music.com :: View topic - AmbiophonicDSP VST Plugin Now Available

-but to each their own.

You can also experiment with varying levels of recursion with the crosstalk cancelation plugin on this page.

Christian’s Blog Spacial Plugins

All of these can be used with foobar or winamp player by loading it into the VST-bridge plugin for each player. You might even be able to use line-in to pass 2 channel audio through the winamp player.

[gooki]

Originally Posted by durwood

Bummer, it shouldn't be that difficult to implement but they probably have other priorities...maybe if or when it's slower for them.

I believe it requires low level reprogramming of the DSP, something they probably
don't have to do with the current filters.

But the more people request it the greater chance someone will make it.

[poldus]

Let´s see if anybody can shed some light on this: I´m running a digital path from cd to laptop to my yamaha AX1 which does the DA conversion. As the volume knob is turned up higher-but within my usual listening level-a noticeable and annoying hiss is present in the tweeters from my listening position.
The culprit is either the computer or the edirol ua-1d adapters. It dissapears when virtual audio cable´s output device repeater is stopped, returns when started. The ambiophonic transcoder aplication makes no difference in this regard, since bypassing it or closing the application has no effect on it.

I have searched the net but found no mention of the issue of hiss in a purely digital chain. All usb/spdif adapter reviews contain the usual audiophile ¨stage width- realism-musicality¨ nonsense but no mention of hiss. Anybody? I will start a new thread if there is no input here.