Mono can be subjective and unique. Mono also has unique virtues that take a little effort to experience. Mono is also enjoying a bit of a "moment" right now as collector interest has expanded to areas that were previously overlooked. Certainly ERC establishing a business model around extremely expensive mono reissues and the ever increasing prices for original Blue Note LPs have attracted a lot of attention.
By the turn of the era from mono to stereo, engineers had largely perfected the art of recording for a single channel. The best recordings of the era were captured using what we now consider as minimalist techniques- a single or just a few mics, everyone "live in the studio" instead of isolated or edited in later. Mono recordings from mid-late 50's exhibit an astonishing amount air, space and ambiance. FR of professional machines exceeded 20hz-20khz. Small groups, soloists and solo instruments sound shockingly real. A well recorded piano in mono can give you goosebumps. While the central image is mostly confined to dead center, many are surprised by the amount of depth that can be heard. There is a real sense of space and placement among musicians. My epiphany came while listening to a mono Ella Fitzgerald LP via a modest but very capable system. It seemed like the back of the studio extended to the horizon.
Stereo was a paradigm shift and engineers struggled with how to exploit the benefits of the technology vs the need to produce something realistic. Recordings of Trains, and ping pong balls moving from right to left and back again were very popular because they easily demonstrated the difference between mono and stereo. Engineers attempted to capture people and instruments in isolation- to be better equipped to enhance the stereo effect, along with mixing for extreme soundstage width- center hole be damned. Meanwhile Mono was given the left handed step child treatment relegated to kids pop, and low income adults who could not afford stereo. Too bad because mono recordings of the 60's are some of the best every. 60's British invasion in full stereo sounds phasey and surreal. Mono sounds cohesive, driving and dynamic. I've compared numerous stereo and mono rock/pop LPs from the 60s, and the mono version is the better copy about 70% of the time. Just about everyone knows that the best versions of Beatles and Beach Boys released are in Mono. Same for the Stones, Who, Kinks, Motown, Stax etc.
Reproducing mono can be as simple as pressing a mono button, our using a Y cable. You will hear a difference, but not all of the quality that is available. Stereo is a combination of vertical and horizontal LP grooves. Mono is horizontal ONLY, and anything in the vertical field is essentially noise. A stereo cartridge heard through a mono button, or Y cable still reproduces whatever is in the vertical portion of the groove. The button or cable is supposed to cancel out this content, but it does not. The presence of vertical content introduces phase anomalies that can be heard. Some don't care, some do- such is the nature of our hobby.
The next step up so to speak is using a stereo cartridge that is adapted for mono- either through internal summing of channels (internal Y cable) and in some cases combined with a rotation of the *2* coils to minimize reaction to vertical content. BUT either method still allows for vertical content to be reproduced with the audible effects mentioned earlier.
The most extreme, and IMHO the best approach, is to use a singe coil mono only cartridge. This design responds *only* to horizontal content and captures nothing from the vertical side. The sound is a revelation compared to a mono button, or even an adapted cartridge. Musicians sound like real flesh and blood. Solo instruments and musicians are reproduced with pinpoint accuracy and a sense of live verisimilitude that is shocking when first heard. True mono cartridges are available from Denon, Ortofon, Miajima and a few others. Some listeners have restored vintage GE (see previous post), Fairchild, Shure, Pickering, Elac mono only cartridges.
The question to ask is how much do you want to get involved with this segement of reproduction ? Do you have only mono reissues from the past 15yrs, do you have just a few golden age mono LPs ? If the answers are yes, then a modern mono cartridge, or the mono button may be sufficient. OTOH if you have several hundred mono LPs (picked up for pennies on the dollar from mono haters....) as well as current reissues, then a dedicated mono (single channel) cartridge may be a justifiable expense.
