Does a real existential threat exist to Quadraphonic?

[Steve Bruzonsky]

I'd say for the majority of members here, the name QQ Quad is just a name. It's pride. Yet, the tagline says; Quadraphonic Quad, Multi-Channel Sound, Past, Present, Future.

Quadraphonic in the mid-seventies is the start of immersive sound. All modern immersive sound started with Quadraphonic. Quadraphonic like Vinyl is here to stay!

 

[Doug G.]

AI - "Joni Mitchell Sings Liberace"!



Doug

 

[furui_suterioo]

I have gotten interesting results running mono recordings through a small hint of artificial reverb and then to a QS decoder. Its as if somehow the reverb allows the decoder to pick out some directionality and doesn't ruin the sound.

 

[MidiMagic]

Going OT...MidiMagic - how about designing a Hafler/DynaQuad passive speaker matrix decoder circuit that rolls off the treble in the surround channel at about 7kHz and also somehow simulates the modified Dolly B NR decoding (perhaps a mild fixed shelf filter that's an average of sliding band frequency range of Dolby B and a cut that's an average of low level treble boost of Dolby B)?


Kirk Bayne

I already have one of those. Width and depth controls vary matrix parameters, switchable back channel treble rolloff. Also has center and subwoofer outputs and autovary logic. Schematic below. Built it in 1995.

I am thinking more about playing SQ, BMX. H and UHJ.

 

[MidiMagic]

I have gotten interesting results running mono recordings through a small hint of artificial reverb and then to a QS decoder. Its as if somehow the reverb allows the decoder to pick out some directionality and doesn't ruin the sound.

It works better if you have a reverb you can pan to a back position in RM. I do this with my mixer, its built-in effects, and my bus 3-4 back encoder. I also have a reverb with two independent channels, so I can spread reverbs set differently to LB, CB, and RB simultaneously.

 

[sjcorne]

There must not be much of an "existential threat" if we're talking about building new quad matrix decoders in 2024

 

[kfbkfb]

I already have one of those. Width and depth controls vary matrix parameters, switchable back channel treble rolloff. Also has center and subwoofer outputs and autovary logic. Schematic below. Built it in 1995.

I'm mainly interested in getting close to proper Dolby Surround decoding with a passive (Hafler) speaker matrix decoder- 7kHz rolloff (I don't see a need to have a 100Hz rolloff too) + a fixed shelf filter to simulate the modified Dolby B NR decoding (used only in the surround channel, IIRC, only 5dB NR instead of 10dB), the starting frequency of the shelf filter would need to be based on the starting and ending frequencies of the Dolby B NR sliding band.

IMHO, the Hafler based circuit to implement good Dolby Surround decoding with the speaker matrix concept should be as simple as possible and only for the surround "channel", L and R signals to the L and R speakers would be unchanged.

Such a circuit design could be very useful since there's so much DS encoded content and no new DS decoders (since 2014).


Kirk Bayne

 

[Stupy]

I'm moderately excited about the potential for AI to extract out stems from mono/stereo recordings. That opens up so many possibilities with loved recordings where the multitracks are either lost or we would otherwise never be able to access anyway.

From there, I figure the ideal would be AI rendering into multichannel configurations (in real time?). But I perceive that defining an ideal quad/5.1/Atmos mix is far from simple. It can and must vary by not only the speaker configuration but the song itself, the album it is from, the artist/s and good luck with personal taste variances.

In other words. The technology will change but I reckon we will be mucking around with this stuff for the forseeable future. Should be fun.

 

[somethingcleveridunno]

Quadraphonic in the mid-seventies is the start of immersive sound. All modern immersive sound started with Quadraphonic. Quadraphonic like Vinyl is here to stay!

Especially as long as those quad mixes continue to be more discrete and adventurous than most newer attempts.

The days when engineers were tripping balls at the console, and the band was too stoned to stop them from panning a Hammond organ solo all the way around the room.

Probably a room-temperature take, but "remaining faithful to the stereo mix" is no virtue at all when you have 2, 3 or 9 more speakers to play with.

 

[somethingcleveridunno]

I'm moderately excited about the potential for AI to extract out stems from mono/stereo recordings. That opens up so many possibilities with loved recordings where the multitracks are either lost or we would otherwise never be able to access anyway.

From there, I figure the ideal would be AI rendering into multichannel configurations (in real time?). But I perceive that defining an ideal quad/5.1/Atmos mix is far from simple. It can and must vary by not only the speaker configuration but the song itself, the album it is from, the artist/s and good luck with personal taste variances.

In other words. The technology will change but I reckon we will be mucking around with this stuff for the forseeable future. Should be fun.

AI stem separation is one of the best uses of machine learning, by far.

But automated upmixing is all gonna sound the same, you can hear the result already by listening to the lesser Atmos mixes out there.

The surround mixing engineer is woefully undervalued by the industry right now, and the use of uninspired lowest bidders who'll knock out multiple mixes in a day probably IS the biggest threat to spatial audio, as enough of those will leave new listeners wondering why they spent money on a surround system.

 

[jimfisheye]

I'm moderately excited about the potential for AI to extract out stems from mono/stereo recordings. That opens up so many possibilities with loved recordings where the multitracks are either lost or we would otherwise never be able to access anyway.

From there, I figure the ideal would be AI rendering into multichannel configurations (in real time?). But I perceive that defining an ideal quad/5.1/Atmos mix is far from simple. It can and must vary by not only the speaker configuration but the song itself, the album it is from, the artist/s and good luck with personal taste variances.

In other words. The technology will change but I reckon we will be mucking around with this stuff for the forseeable future. Should be fun.

There are so many subjective elements in a mix! Sometimes mistakes happen and sound cool and then there it is. Just like a band playing together morphs and builds on material beyond any script as a unit more than any of the individuals. Mixes often evolve the same way. AI will just sound like another cut/pasted <insert name of current pop star> album. Humans using this stuff as tools might get interestingly dangerous though!

I think the stem separation will evolve though! It's very crude right now and the artifacts are glaring. I mean the best efforts too. You can get away with "partial" stuff now though. And I mean cleanly and it would get past audio experts in court. You can boost or attenuate mix elements using separation techniques. Full separation and exposure in a new surround with no artifacts is a tall order. I think that's a least around two more corners.

 

[jimfisheye]

Is there an existential threat to quad?

Are you kidding? We just started hanging full quad systems from the ceiling to extend our 7.1 array!

 

[Electric Moo]

I’ve processed 100 albums through Penteo and thrilled with the results. Fubar 2000 through a surface pro tablet and Asus USB interface into six channel amps.

Current view during playback

You drive an EV & have figured out how to tap into the power grid?

Nice view, waiting for the charge

 

[kfbkfb]

Regarding a threat to quad/surround - Sadly (IMHO), due to listeners listening to stereo songs in mono on their smartphone speakers, the sound of new stereo mixes downmixed to mono takes on increasing importance.

Perhaps, in addition to monitoring the stereo mix in mono, it could also be monitored in fake surround sound (maybe Hafler, maybe one of the DTS systems, maybe using the DSU system).

With surround sound pretty much the norm in movies, TV shows and video games, mixing stereo mixes in such a way as to have more out of phase content than the typical stereo mix (and thus provide something for a matrix decoder to latch on to to create fake surround sound) would be a way to have the best of 3 worlds (mono, stereo, surround) in a single mix.


Kirk Bayne