is the 1990s "WIDE MODE" setting the 'soundstage' of today, and a gimmick?

 Could be.  

A trick you can use in the studio to get a faux wide soundfield is to place a delay on either the left OR right channel (not both) and set a small MS delay. Probably some derivative of whats happening. Easy enough to implement in budget gear.

I've been using a Caver C9 sonic hologram in my system since I bought it in the late 80s. A few years back I had it rebuilt and modified to a higher standard. I'm sure a lot of people here would  poo poo it but unless you hear it in a system that has a good sound stage already it can be amazing. The soundstage opens up in every way and the instruments and vocals  become way more singular. I've used it since the late 80s and I hope to still be using it when I'm in my late 80s lol

@fai_v 

No. High end gear has not implemented this stuff as a trick. High Fidelity reproduction is really difficult and those most successful at good reproduction have spent incredible time and effort simplifying and choosing the highest quality parts to touch things less in order to better capture the real thing. 
 

Play with the signal and the hi fidelity goes away. It’s not a thing.

One of the reason I'm not a big fan of speaker crossovers being potted. I can't see or fix the silly things, usually. I don't like it when the speakers are wired out of phase to get a flatter response, either. OB you almost can't help it but in a box, yuk..

Regards

Electronic gimmickry like that is fine on less expensive gear, like a a boom box. But it is a detriment on higher end gear. 

Yes but i wonder if any current high end gear is secretly implementing these tricks?  Throw in a couple of capacitors/resistors whatever in one of the channels, throw off the phase and increase the soundstage?  Perhaps a little sleight of hand with a microchip or two?

I don't know i'm just speculating, but I agree with you it would be a detriment and a crime for a company to do that without letting buyers know.

Electronic gimmickry like that is fine on less expensive gear, like a a boom box. But it is a detriment on higher end gear. 

IFI 3D Holographic. 

I a BBE 25 years ago but it wore out.

Implementing a processed signal to imitate a big sound field as you point out is not new. It has been done on low FI stuff for a long time. Actually the iPad does an amazing job of creating a big sound stage.

‘But a new high fidelity piece of equipment has to do it by great fidelity. Fooling sound with the signal always creates fundamental sonic problems.

One piece of effective tech that created nearly a 360 degree sound field is Q Sound. But this is processing done in the recording. Roger Waters, Banco de Gaja and a few others have used it. In Amused To Death you can hear a dog bark behind you… among other amazing tricks. This technology allows you to keep fidelity. In some of the Banco da Gaia… Maya (I think)… the strongly low frequency music moves out from the the sound stage all the way to one’s side. Amazing really.

You can google Q Sound Recordings to get a list of albums using it.

I had an EQ that had an "Expander" button, or some such thing on it.

Sounded awful then, and I'm sure it still sounds awful.

:)

There were a couple of versions of this. Some used comb filters, others simply blended in the anti-signal from the other side, and some reversed polarity completely. 

 

When i read reviews of someone swapping in a new device, and is experiencing a new breathtaking soundstage,

I literally had a thread devoted to the topic of reviewers claiming that the new device is so revolutionary they have to listen to their entire music collection all over again, and IMHO it's bullocks.  Just the reviewer trying to justify their existence.

Dream on.