Has anyone tried a Hafler circuit for surround sound?

[guussie]

Has anyone ever tried a Hafler circuit with an Expert Pro?

A Hafler circuit is used to create a surround sound effect:

Hafler Circuit

I am interested in trying this but if anyone has tried this (with or without SAM), it would great to read your experience.

[David A]

A long time ago, pre Devialet. Not pre my Devialet, I mean back in the days when the company Devialet was not even a twinkle in anyone's eye, not even the eyes of its founders.

I think it was back in the days of quadraphonic LPs that I tried it and that was back in the days when digital audio didn't exist.

Back then it was touted as the poor man's way into quadraphonics when quadraphonics, the first real attempt at surround sound, was the cutting edge. Quadraphonics fell way short of the performance of current surround sound techniques.

What I remember it delivering was more of a sense of sound around and behind the listening position than a sense of the actual performers being placed around the listening position. In other words it delivered more of a sense of ambience than of an actual soundstage surrounding the listening position. If what you want is to have a soundstage in which performers and/or sound effects if this is for home theatre purposes are clearly located around and behind you it's probably going to fall short of what you're looking for.

I'm digging into 40 year old memories here. If you've got the extra pair of speakers and the speaker cables to do it then try it for yourself but definitely do not expect to get the kind of results you get from discrete multi-channel surround sound source material. You still only have 2 discrete channels of information, you're playing with the out of phase info in the 2 stereo channels to deliver a different presentation to the sides and rear than you get from the acoustics of your room with normal stereo. It will not deliver the kind of localisation of sound sources to your sides and rear that you get from a modern discrete 5 or more channel soundtrack on a video disc or the 5 channels of surround sound on some SACDs.

[BoyScout]

Has anyone ever tried a Hafler circuit with an Expert Pro?

A Hafler circuit is used to create a surround sound effect:

Hafler Circuit

I am interested in trying this but if anyone has tried this (with or without SAM), it would great to read your experience.

That´s completly new for me, and very interesting to know about just from a technical and historic point of view.

[guussie]

A long time ago, pre Devialet. Not pre my Devialet, I mean back in the days when the company Devialet was not even a twinkle in anyone's eye, not even the eyes of its founders.

I think it was back in the days of quadraphonic LPs that I tried it and that was back in the days when digital audio didn't exist.

Back then it was touted as the poor man's way into quadraphonics when quadraphonics, the first real attempt at surround sound, was the cutting edge. Quadraphonics fell way short of the performance of current surround sound techniques.

What I remember it delivering was more of a sense of sound around and behind the listening position than a sense of the actual performers being placed around the listening position. In other words it delivered more of a sense of ambience than of an actual soundstage surrounding the listening position. If what you want is to have a soundstage in which performers and/or sound effects if this is for home theatre purposes are clearly located around and behind you it's probably going to fall short of what you're looking for.

I'm digging into 40 year old memories here. If you've got the extra pair of speakers and the speaker cables to do it then try it for yourself but definitely do not expect to get the kind of results you get from discrete multi-channel surround sound source material. You still only have 2 discrete channels of information, you're playing with the out of phase info in the 2 stereo channels to deliver a different presentation to the sides and rear than you get from the acoustics of your room with normal stereo. It will not deliver the kind of localisation of sound sources to your sides and rear that you get from a modern discrete 5 or more channel soundtrack on a video disc or the 5 channels of surround sound on some SACDs.

Interesting perspective!

I indeed have a pair of extra/spare speakers and would like to try.

I obviously forgot to mention that I am most concerned about damaging my Devialet Expert, so any input on that would be highly appreciated.

I am extremely happy with the Devialet's performance in just stereo mode, so this would only be used for video/Netflix/AppleTV+ type of applications.

Thanks for your write-up!

[Jean-Marie]

A long time ago, pre Devialet. Not pre my Devialet, I mean back in the days when the company Devialet was not even a twinkle in anyone's eye, not even the eyes of its founders.

I think it was back in the days of quadraphonic LPs that I tried it and that was back in the days when digital audio didn't exist.

Back then it was touted as the poor man's way into quadraphonics when quadraphonics, the first real attempt at surround sound, was the cutting edge. Quadraphonics fell way short of the performance of current surround sound techniques.

What I remember it delivering was more of a sense of sound around and behind the listening position than a sense of the actual performers being placed around the listening position. In other words it delivered more of a sense of ambience than of an actual soundstage surrounding the listening position. If what you want is to have a soundstage in which performers and/or sound effects if this is for home theatre purposes are clearly located around and behind you it's probably going to fall short of what you're looking for.

I'm digging into 40 year old memories here. If you've got the extra pair of speakers and the speaker cables to do it then try it for yourself but definitely do not expect to get the kind of results you get from discrete multi-channel surround sound source material. You still only have 2 discrete channels of information, you're playing with the out of phase info in the 2 stereo channels to deliver a different presentation to the sides and rear than you get from the acoustics of your room with normal stereo. It will not deliver the kind of localisation of sound sources to your sides and rear that you get from a modern discrete 5 or more channel soundtrack on a video disc or the 5 channels of surround sound on some SACDs.

Interesting perspective!

I indeed have a pair of extra/spare speakers and would like to try.

I obviously forgot to mention that I am most concerned about damaging my Devialet Expert, so any input on that would be highly appreciated.

I am extremely happy with the Devialet's performance in just stereo mode, so this would only be used for video/Netflix/AppleTV+ type of applications.

Thanks for your write-up!

I doubt that you risk damaging your Devialet Expert for the following two reasons:

1. The expert is very efficiently protected against shorts and any over current drawing etc... I have seen demonstrations by the creator of the amplifier where he was unplugging the cable from the speakers and shorting them while he was playing at full power with no other effect than the display showing that there was an issue with one speaker and the shorted side shutting down itself. And the moment it was no longer shorted, everything back into normal.
   
2. The rear speakers will behave like a 16 ohms (assuming individual ones are 8, of 8 ohms if you start with 4 ohms speakers) and the way that '16 ohms speaker) is connected to the amplifier is exactly how speakers are connected to an Expert in Mono mode.
   

My two cents,

Jean-Marie