Monaural Hi-Fi Musings

[mashaffer]

Since most of us here are kinda retro I thought I might post some thoughts on this topic and see whether we can get an interesting discussion going. I hope this is not too far off topic (don't want to cause any trouble).

I have been working on a couple of simple mono SS amps to use up some parts that I have laying around and to brush up on electronics. One project is a simple class A My Class A thread that I plan to use later on for some experimentation with horns. In any case a side effect of all this was to get me thinking about mono music systems.

Up until about 40 or 50 years ago all Hi-Fi's were mono. Being a young whipper-snapper I have never known anything but stereo. I was wondering if any of you have enough experience with mono-hi-fi to comment on it's relative merits.

Here are a few random thoughts to get things going.
[list=1][*]To a certain degree stereo reproduction is somewhat artificial at least as it is currently practiced. Multi-mixdown and panning from single mics gives an illusion of aural space but does not actually capture it. Also I have never seen anyone with their ears six feet apart.[*]In practice many live music events seem to be essentially single point sources. This is not true of chamber music in a small room but it seems valid in regard to a rock concert or orchestra concert.[*]Many SE Class A tube amps and amps without global feedback are said to present a much better sound stage. I wonder what such an amp does to the sound of a mono system. Does the mono system benefit from the increased detail from such amps or does the improvement strictly relate to stereo reproduction? Has anyone done any listening tests of this type?[*]When I speak of mono I mean a single loudspeaker system not a stereo with the same signal fed to both channels. I would think the clarity would be better with single speaker system.[*]When I have listened to mono systems I have noticed that I still get some ambiance from the listening room acoustics so that the sound is not as one dimensional as I would have expected.[*]I wonder if there is any difference between older mono recordings v.s. stereo recordings when played through a mono system. In other words does the stereo recording process muddy the waters when played back on a mono system?[*]I wonder if the home theater folks might have it backward (stereo main channels and a center channel to fill in action directly in front). Maybe the better approach would be a very high quality center channel (L+R) as the main source with smaller stereo channels to optionally add some ambience. The stereo channels would be at a much lower level much like rear speakers in typical home theater applications. In this layout the main source would seem to come from the stage (center) with room characteristics added by the outer stereo channels rather than speading the main sound image across the entire room.[*]It just seems to me that all advances have good and bad aspects and certainly I would expect stereo to be the same way. I bet that a "you are there" feeling is possible with single channel equipment. I may just experiment with this by setting up a mono system in the music room once I get the speaker cabinet for my utility amp made up.[/list=1]
So let's here it. What are your thoughts and experiences with minimalist (1 channel) hi-fi? I would especially like to here from those of you with enough life experience to have grown up with mono (the sound not the disease).

[Eli Duttman]

Moose,

I'm old enough to remember the arrival of stereo. I'll make a few remarks in no particular order.

A mono phono cart. responds only to motion in the horizontal plane. A stereo LP is made with the sum of the 2 channels recorded in the horizontal plane and the difference between the 2 channels recorded in the vertical plane. That system allows a mono cart. equipped with an appropriate stylus to play a stereo LP and a stereo cart. to play a mono LP.

You are correct about mono capturing ambiance info. I own a Mercury LP of Marcel Dupree playing a church pipe organ. The notes on the dust jacket explain the care that was taken in placing the single "mike" to ensure that the church's reverberation was captured.

A you are there experience is best achieved when small ensembles are recorded with minimal miking. That way, ambiance cues are not fouled up and the size of the reproduction venue approximates that of the performance venue.

[sreten]

JMO but mono sounds far better through 2 speakers
optimally placed for stereo then a single speaker.

There is a difference between mono and stereo recordings.

If you mono a stereo recording you generally lose a lot of
the top end due to minor phase differences between the
two channels, ambience in particular suffers a lot.

This is easy to confirm with a tuner on a good signal set to mono.

IMO you will not get too far with good stereo recordings played
over a mono system, conversely some of the older "stereo"
recordings sound better in mono, or better still using a stereo
blend (ambience) circuit (also known as a shuffler) to reduce
channel separation.

There is quite a lot of info in older books of how to cope with
the "evils" of stereo (really actually poor stereo recording
practises) such as vocals in the left channel, guitars in the right.
(Mono recordings "reprocessed" for stereo are particulary evil).

This basically involves a pre-amp that converts stereo to mono
plus a sum+difference channel, being able to seperately process
the two signals, and then recombining them back to stereo.

sreten.

[pinkmouse]

I have moved your thread to EE, it may get you a wider audience here

[mashaffer]

Thanks for the move. I wasn't entirely sure where the best spot was.