NRDC-Ambisonic Surround Sound Decoder

[bigbillquad]

I came across this on eBay I have never seen one before...

( https://www.ebay.com/itm/NRDC-Ambis...119735?hash=item262564cab7:g:QYQAAOSwDYVdWBWx )

 

[jefe1]

Hey it does everything! But when you look inside all the buttons close the same circuit.
Reminds me of the trash cans at Costco. The lids have three openings labeled food waste trash and recycle so you are careful which slot you toss your trash into. But when you look at the can with the lid off its just one barrel with a trash bag nothing separate. Someone has a sense of humor.

 

[Mark Anderson]

I came across this on eBay I have never seen one before...

( https://www.ebay.com/itm/NRDC-Ambis...119735?hash=item262564cab7:g:QYQAAOSwDYVdWBWx )

Too cool, my dream machine back in the day because it did B-Format and matrix decode

 

[Sonik Wiz]

I came across this on eBay I have never seen one before...

( https://www.ebay.com/itm/NRDC-Ambis...119735?hash=item262564cab7:g:QYQAAOSwDYVdWBWx )

View attachment 42888

Yup, got one of those retired to my Closet of Quad:

Originally available as a kit published in Wireless World & supplied by Integrex. A hundred years ago I honeymooned in the UK & bought assembled at the Integrex factory. It did a whole lot of stuff, not very well in my opinion.

 

[par4ken]

Yup, got one of those retired to my Closet of Quad:
View attachment 42894

Originally available as a kit published in Wireless World & supplied by Integrex. A hundred years ago I honeymooned in the UK & bought assembled at the Integrex factory. It did a whole lot of stuff, not very well in my opinion.

I remember how Bill Sommerwerck (in MCS Review) used to rave about Ambisonics, everything else was just wrong. I've been looking for a decoder on and off for some time now and they seldom show up. Back in the day I never bothered with Ambisonics as ther just wasn't any worthwhile programm material available. Being a non-logic type decoder it relies on phase as much as amplitude to image sounds I would think that it would sound best in a small room with closely spaced speakers.
The Sansui QS-1 with it's weird phase modulation of the rear channels sounds very nice in a small room, but does almost nothing in a large room with farther spaced speakers, could be the same case here?

 

[Sonik Wiz]

Too cool, my dream machine back in the day because it did B-Format and matrix decode

In those days I did everything I could to experience all the different formats of surround sound. The only one I couldn't reach my own personal consensus on was Ambisonics. Mainly for 2 reasons being I never had the chance to hear a B format recording and secondly all the rerecords I did hear was quite unimpressive jazz/classical/cheesy demo.

Technically B format should have been very good but was unavailable just being an intermediate format between a microphone & UHJ. And UHJ was a mess not sounding all that different to me from basic RM decoding. Ambisonics never had Pink Floyd or even Blue Oyster Cult to show off what (maybe) could be done using popular music.

I see a couple Ambisonic B format microphones on ebay ranging from $300 to $900. Are these actually being used anywhere today? In commercial or just personal interest recording?

Edit. I do have Parson's Stereotomy which is UHJ encoded. As far as I know that's as close to big time popular musician that Ambisonics had. Ironically it sounds best played in 2 ch stereo. UHJ makes the width very wide , a bit beyond 180 deg & the instruments/sounds seem to be placed even at an identifiable distance from the listener. But move your head a few inches & the effect is gone.

 

[Sonik Wiz]

I remember how Bill Sommerwerck (in MCS Review) used to rave about Ambisonics, everything else was just wrong. I've been looking for a decoder on and off for some time now and they seldom show up. Back in the day I never bothered with Ambisonics as ther just wasn't any worthwhile programm material available. Being a non-logic type decoder it relies on phase as much as amplitude to image sounds I would think that it would sound best in a small room with closely spaced speakers.
The Sansui QS-1 with it's weird phase modulation of the rear channels sounds very nice in a small room, but does almost nothing in a large room with farther spaced speakers, could be the same case here?

Thanks for the reply Ken.
I would have to agree with Sommerwerck at least in theory. B format could have sounded quite good who had a chance to hear that? Your right about the Intgegrex non-logic decoding. Pushing buttons down the row didn't seem to make much diffence. I couldn't say on any of the decoding modes Aha! That's it. Sounds great. The Stereo & Super Stereo was the simplest of stereo enhancement no different to my ears than a simple Hafler or original EV decode. And Ambisonics used a very complex way to do a simple thing.

I had the Sansui QS-1 also! My 1st piece of real quad equipment. Very classy looking. The odd phase modulation in the rear channels was dropped as soon as Variomatrix evolved. Still I maintain to this day I have never heard Garfunkel's Angel Clare in SQ sound as good as it did on the QS-1.

 

[DuncanS]

Yup, got one of those retired to my Closet of Quad:
View attachment 42894

Originally available as a kit published in Wireless World & supplied by Integrex. A hundred years ago I honeymooned in the UK & bought assembled at the Integrex factory. It did a whole lot of stuff, not very well in my opinion.

It was on my wish list, but at the time I was a student and I didn't have the money so I eventually built an non-logic SQ decoder using the Motorola IC, and knocked together a Quad system by adding my father's cast off stereo to mine!

 

[Mark Anderson]

I see a couple Ambisonic B format microphones on ebay ranging from $300 to $900. Are these actually being used anywhere today? In commercial or just personal interest recording?

Edit. I do have Parson's Stereotomy which is UHJ encoded. As far as I know that's as close to big time popular musician that Ambisonics had. Ironically it sounds best played in 2 ch stereo. UHJ makes the width very wide , a bit beyond 180 deg & the instruments/sounds seem to be placed even at an identifiable distance from the listener. But move your head a few inches & the effect is gone.

I know a lot of folks that still use a calrec or similar soundfield mike and too this day most Nimbus classical recordings use them and encode to UHJ. I find the Nimbus titles enjoyable to listen to.

I have to say that I enjoy Stereotomy decoded in UHJ. You really need to get used to the sound but once I do the speaker locations and the walls in my room disappear. That is what I really enjoy about Ambisonics is sound location is not merely made by volume but also phase which is what happens in real life and eliminates speaker pull where the sound is emanating from the surface of my speaker box.

B-format is what Dolby Atmos and Auro-3D are trying to be but unfortunatley they are still only volume based localization.

 

[tryphon]

A peek inside the one I built.

 

[Sonik Wiz]

A peek inside the one I built.

That is pretty cool! 10 million resistors but a silver panel with black buttons? What is that blue knob in upper left? Maybe it's there in mine but so long ago.
What you think of the music reproduction?

 

[tryphon]

That is pretty cool! 10 million resistors but a silver panel with black buttons? What is that blue knob in upper left? Maybe it's there in mine but so long ago.
What you think of the music reproduction?

The panel is actually black. I built this from scratch, with premium components and mil spec capacitors. I only had the bare PCB from Integrex. It was the last one they had in stock. The board has been upgraded with better op-amps. It sounds very clean and the new op-amps have a very good slew rate. The knob adjusts the input sensitivity.

 

[Soundfield]

I've found a picture of the one I built. I think the photo dates from about 1979 and shows a pile of equipment in the corner of my bedroom. I thought it was an awful decoder. Looks from this photo that it had already been edged out of the system and was just idly sitting on top of my graphic equaliser-

And by the time a year or so later when I'd had a cabinet built to tidy up the equipment it had obviously been discarded altogether-

Not that it was something I ever missed (unlike that Revox tuner which I foolishly sold when a bit short of cash). The cabinet still exists though - my 95 year old Dad uses it for books!

 

[tryphon]

I've found a picture of the one I built. I think the photo dates from about 1979 and shows a pile of equipment in the corner of my bedroom. I thought it was an awful decoder. Looks from this photo that it had already been edged out of the system and was just idly siting on top of my graphic equaliser-
View attachment 78896
And by the time a year or so later when I'd had a cabinet built to tidy up the equipment it had obviously been discarded altogether-
View attachment 78897
Not that it was something I ever missed (unlike that Revox tuner which I foolishly sold when a bit short of cash). The cabinet still exists though - my 95 year old Dad uses it for books!

It needed better op-amps and a better power supply. With those mods, it sounds great.

 

[Soundfield]

It needed better op-amps and a better power supply. With those mods, it sounds great.

I think what it really needed was a better circuit!
You might have improved the ‘sound’ of the thing but it just couldn’t decode quad very well. It was quite expensive even in kit form and I was very disappointed in its performance. It was so poor in positioning and separation (even compared to the el-cheapo decoders I’d heard until then) that I thought it wasn’t working properly and spent ages fault finding on it only to conclude there was no fault. My experience of using it was pretty much the same as Sonik's.....

Pushing buttons down the row didn't seem to make much difference. I couldn't say on any of the decoding modes Aha! That's it. Sounds great. The Stereo & Super Stereo was the simplest of stereo enhancement no different to my ears than a simple Hafler or original EV decode. And Ambisonics used a very complex way to do a simple thing.

 

[par4ken]

Just doing a bit of listening with my Troy Ambisonic Processor and it sounds very good on UHJ but not so great on stereo enhance. So without an Ambisonic source I guess that results may vary. I didn't notice a lot of difference adjusting the width control either but my listening tests have just started. I just wish that there were some good popular music titles in UHJ!

 

[LuvMyQuad]

Just doing a bit of listening with my Troy Ambisonic Processor and it sounds very good on UHJ but not so great on stereo enhance. So without an Ambisonic source I guess that results may vary. I didn't notice a lot of difference adjusting the width control either but my listening tests have just started. I just wish that there were some good popular music titles in UHJ!

There is the Alan Parsons Project...

Stereotomy - Wikipedia

 

[Sonik Wiz]

Just doing a bit of listening with my Troy Ambisonic Processor and it sounds very good on UHJ but not so great on stereo enhance. So without an Ambisonic source I guess that results may vary. I didn't notice a lot of difference adjusting the width control either but my listening tests have just started. I just wish that there were some good popular music titles in UHJ!

Thanks for the update! What UHJ music are you listening to?
I notice that Ambisonics seems to be the new thing among indie bands among various (legit) download sites. Poke around a bit. Maybe you will find a hidden gem to rock out to.

 

[LuvMyQuad]

There is the Alan Parsons Project...

Stereotomy - Wikipedia

Edit: here is an idea, you can even compare a live decode of AAP with the very good software decoded transfers that are "out there".

 

[par4ken]

Thanks for the update! What UHJ music are you listening to?
I notice that Ambisonics seems to be the new thing among indie bands among various (legit) download sites. Poke around a bit. Maybe you will find a hidden gem to rock out to.

"The Sounds Of Canterbury" supplied by a very nice person here! I don't think that I have anything else UHJ. I'm currently listening via the little speakers surrounding my work bench.