MidSide Enc Dec question

[abbey road d enfer]

attached a better res schem

and input vs encoding vs out

Your voltage sources make no sense. The signal amplitude is 1.228Vx2, which is +7dBu.
Spice voltage sources use the peak Amplitude, not the rms value.
So there's a double mistake.
A balanced +4dBu (1.736Vp source can be represented with two -2dBu (0.868Vpk) sources in series.

 

[richiyobs]

Thanks again for precious infos

 

[Jen]

Hi folks
trying to have a mid side encoder decoder with insert points to use with external devices....

is this a possible way?

thanx a lot for your attention
best

Why reinvent the wheel. Wayne Kirkwood has had a board available for years, designed with THAT chips, that has all the features you need, works fantastic, and is very moderately priced. It has send/receive functions. I have one and it works just fine, has for several years. I also have other MS systems built with transformer matrix by both Jensen and Cinemag and customs by PEARL ( Bill Perkins) up in Canada. They all have a slightly different sound, and in several of them I have selectable High Pass in the matrix, and level controls, to adjust image width of pre existing stereo recordings. Strongly suggest the Kirkwood boards, easy build and proven fault free.

 

[abbey road d enfer]

Why reinvent the wheel. Wayne Kirkwood has had a board available for years, designed with THAT chips, that has all the features you need, works fantastic, and is very moderately priced.

I would tend to agree, if the ultimate PO's goal was to produce a better or cheaper solution, but actually I think the OP is enjoying the journey more than the destination.
Of course, he's treading trodden paths and doing the mistakes many have done before. At the end he will have learnt something.
I believe it's the most important virtue of DIY.

 

[MidnightArrakis]

Hi folks
trying to have a mid side encoder decoder with insert points to use with external devices....

is this a possible way?

thanx a lot for your attention
best

GREETINGS!!! -- I just accidentally came across this website this evening and since I have seen this thread about your M/S Encoder/Decoder idea, I just thought that I would include and paste this information here for you to check out.....

https://www.waynekirkwood.com/forum/php/viewtopic.php?t=1272&sid=e1cf592a7def74085db6cc0f58c9d589



Best of luck to you on your project!!!

JBW

/

 

[MidnightArrakis]

OOPS!!! -- I just noticed that the information I have just found is the SAME information that JEN was referencing to!!! My bad!!!

/

 

[richiyobs]

Thanks for all your info...
I won t reinvent wheel, just tried to apply concepts in electronic...
And a place to do this is this great forum
I know my way to do stuff is rude and insane but I ve got no basic knowledge....
I move faders... I m a soundman
It s only few time I can use Ltspice and read and trying to understand what s going into a schematic
Electronic has become my new hobby!

Best
Richi

 

[Jen]

Thanks for all your info...
I won t reinvent wheel, just tried to apply concepts in electronic...
And a place to do this is this great forum
I know my way to do stuff is rude and insane but I ve got no basic knowledge....
I move faders... I m a soundman
It s only few time I can use Ltspice and read and trying to understand what s going into a schematic
Electronic has become my new hobby!

Best
Richi

Very cool! Welcome to the hobby. Lots to learn for sure, a lifetime experience building is ahead of you. Many here will gladly help and teach.

 

[richiyobs]

About KA projects...
The stereo widht control is a great device... I rebuild one few days ago... The image is very coherent without missing energy at the center when totally spread ... I believe the crosstalk is well done and blended within channels... But not so expert to say it s true....
Anyway a good tool to have

 

[richiyobs]

Of course no That IC... But using standard ones.... Tl084
I ve got lots of them from old dismissed console... Why not use them!

 

[RuudNL]

Because with 'normal' components you will never get the channel separation you can get with the laser trimmed THAT ICs. (It is all a result of the tolerance of the surrounding components.)
I have tried this before, but when I had got the L->R crosstalk optimal, the R -> L crosstalk suffered and v.v.
The Wayne Kirkwood design works great and as far as I know is even used in some commercial products.

I use this principle in the Vinylmaster (a pre-vinyl mastering unit). It has a combination of a L/R to M/S encoder, a M/S to L/R decoder, with inserts in the M/S channels. Also there are steep low-cut and high-cut filters and a elliptic equalizer. (To avoid phase difference at low frequencies.)

 

[richiyobs]

Because with 'normal' components you will never get the channel separation you can get with the laser trimmed THAT ICs. (It is all a result of the tolerance of the surrounding components.)
I have tried this before, but when I had got the L->R crosstalk optimal, the R -> L crosstalk suffered and v.v.

Fine... Good to know!
Thanks

 

[abbey road d enfer]

Because with 'normal' components you will never get the channel separation you can get with the laser trimmed THAT ICs. (It is all a result of the tolerance of the surrounding components.)
I have tried this before, but when I had got the L->R crosstalk optimal, the R -> L crosstalk suffered and v.v.

Is that such a big issue? It's been shown times and times again that, for normal listening conditions, 40dB separation is indiscernible from near infinite (100dB) separation.
That excludes experiments done with single-tones on headphones.
40dB is the typical separation achieved by FM tuners. Several designers burnt the midnight oil improving this figure. IIRC they achieved about 60+dB, but the perceived improvement was elusive.

 

[RuudNL]

For some people -40 dB crosstalk may be enough. But not for me though...

 

[abbey road d enfer]

For some people -40 dB crosstalk may be enough. But not for me though...

In what circumstances? The only circumstance I know of that requires more than 40dB separation is broadcast game clean feeds, where a candidate receives a specific program where crosstalk from unwanted sources is proscribed. The Radio France specs in that case is more than 70dB 20Hz-20kHz.
For typical music listening, the level of separation achieved in FM and vinyl records of about 40dB has never been a problem.
I don't know a record that didn't sell because it had excessive X-talk.
In the case of headphone listening, it is well known that almost infinite separation is not welcome; that's the reason why HRTF coders are used.
An audiologist may certainly vouch for the need of extreme separation, though.

 

[alphasnk]

You guys are great, thank you

 

[richiyobs]

If I don t go wrong Xtalk in a certain percentage was a secret weapon for Plugin developers when introduced.. But it s another story and world...

Best