fake stereo vs. mono

[steveidosound]

Don't want to stir things up too much, but I was reading an album jacket of a Capitol "Duophonic" re-processed fake stereo record which described their process as  having a "dimensional two-speaker effect" with "no (annoying) centering and none of the disappointing letdown of hearing mono discs on stereo equipment." :-)

This got me thinking again about the best way to listen to mono. There were other pieces of advertising hype at the dawn of stereo that did tout having a 2 speaker stereo system as preferable for giving mono sound from your old records "spaciousness".

On this very forum I have heard talk about some depth of image in playing the mono TP releases on a stereo system. Although this may be subjectively more pleasing in any case,  all of the above tends to fly in the face of what I  understand from a technical point of view should be correct.
 
That is to say that a mono source should, if everything is perfect, sound like a single point source of sound.  If played on 2 speakers, the best image would sound exactly as if there is a phantom point source in the center. Even better would be a single mono point source speaker in the center to prevent the variables of two different acoustic paths in the room from the speaker to the listener. and on the tape side, wouldn't tiny phase variations of two identical mono tracks played on a stereo machine be inferior to just the one track played through one amp and speaker? Obviously TP releases played on a proper machine represent the best case scenario. The worst case being something like a mono source material cassette recorded on both channels of a stereo tape with the outputs of the stereo deck combined to mono. If you have ever tried this, the flanging/combing effects from tape skew make it all but unlistenable.

So, is this another case of slight theoretical imperfections making the subjective experience better? Do we need a bit of de-correlation of our mono?

BTW the Capitol Duophonic was probably the best sounding "de-correlation" technique. Much better than the "boost the highs in one channel and lows in the other" methods used by others.

[Teeg]

  A friend of mine collects and listens mainly to mono (vinyl) recordings, claiming that there is more detail available as the needle does not have to divide its attention between two tracks of information; more resolution.  His system consists of older Marantz gear feeding Klipsch corner horns, sitting quite far apart with a tight toe-in angle...obviously 90 degrees from the listening point.
 
  I've often noticed on his system that the mono discs present an image which is definitely not point-source as you might expect, in fact I've had to ask at times if the recording currently in play was stereo or mono. This does not apply to all recordings; some offer more stereo information than others, yet there are discs where the stereo recording seems to contain little difference between tracks (or sides of the groove, whichever is correct). I don't know what it is about his setup or placement that affords the illusion of depth to his mono recordings, but it does seem to be there.

  Some time back I purchased a few boxes of tapes, blues/jazz professionally recorded on 10" reels. The seller indicated they were stereo recordings but sampling a few indicated they were mono (I do have a mono 440 deck). Perhaps its time to dig them out and have a second listen. If they are indeed mono it might be interesting to see what kind, if any, of an image the present on my stereo setup.

Tj

[docb]

The sense of stereo image from a mono recording on a stereo system is possibly influenced by timing and level balance differences between the two speakers. One should probably listen on just one channel to determine just how much the presentation changes compared to two. As a matter of fact this is a great way to hear if your stereo speakers are tonally balanced left to right and equidistant. Take it from someone who has been trying to balance a three way active system with four amps and twelve drivers for the past couple of days...

[astrotoy]

Hi folks, I don't hear a stereo image from a mono record or tape, certainly not the kind of stereo image I hear from a good stereo source. However, I do hear depth and body in the mono image that makes me forget that I am hearing a stereo image. This may be caused by slight differences in the channels or differences in the speaker responses or differences in the acoustical environments ofthe two speakers. I think that Ironbut might be able to give a perspective from listening to a mono source with a good pair of stereo headphones, where the acoustic variables of playback are minimized.  In any case, I have found several really fine mono recordings (in addition to the TP mono releases) that produce this rich depth and body. In fact, the best one so far, a mono issue of the Joan Baez "Farewell Angelina" album is better to my ear than the stereo version, in terms of depth and body. I normally switch to a mono cartridge to listen to mono records  (mine is a Lyra Helicon mono). BTW, my experience with artificial stereo has not been good. I have a few of the old Capital Duophonic and some EMI classical which were reissued in electronic stereo.  I think the standard procedure was to divided the mono signal into low and high frequencies and put the high primarily in the left channel and the low primarily in the right. This gives a stereo like spread to the sound image, but with a great artificiality.

Larry

[steveidosound]

Hi.
I typically find that a mono recording through phones sounds as if it were coming from the middle of your head.
I think the reason one would use a mono cartridge is similar to the one about listening to one track of a mono tape rather than 2 identical tracks. Less chance for any phase or frequency irregularities between what are supposed to be 2 identical sources. (groove walls / tape tracks). But that was my earlier point, some de-correlation of the single point source, whether by accident of slight differences or imperfections of the two channels electrically, mechanically or acoustically, tends to give a pleasing result and an illusion of more depth to the sound than you would get with a single track / single speaker configuration. This is what they were trying for with the various fake stereo enhancement schemes back then, though those were often so over done that each channel sounded rather awful by itself.

There may be other reasons for great mono however. In pop music , when stereo was considered more of a "novelty", more careful attention was often given to the mono mix. And with records cut with Westrex cutters, my disc mastering friend says, and I agree from informal listening tests, that their last generation mono cutter sounded better than at least their first generation stereo one.