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Reading Art's notes on mono in the December issue got me to thinking; how would you go about building a decent, dedicated mono system in 2008?

Obviously you can still buy mono phono cartridges, but what would you do next?

The main purpose of such a system would obviously be to play mono lps...

Scott A.
Watertown NY

Buy a true dual mono integrated stereo amplifier with separate power leads for each channel then cut the damned thing down the middle with a hacksaw and attach the spare side panel from the other amp half.............

When I think of modern mono, I still think two speakers.

Typically, it seems even mono enthusiasts enjoy the effect of two speakers imaging.

You will often see them talk about how the sound is all center fill, but fleshed out and even three dimensional in some regard.

Listening to mono in true mono (one speaker,) strikes me as a far inferior experience.

Even the revered Beatles mono recordings are best enjoyed on a two channel system.

Stereo mono is better than mono mono, to me.

So, for a modern mono system, I'd say hit your turntable with a mono cartridge and enjoy the sound!

Listening to mono is making a choice. Do you want to hear the sound mainly as it was when it was recorded? This would in many ways be the way the artists "intended" the music to be heard. For that, a single speaker placed appropriately in the room would be the best solution. Corners were typical locations for speakers due to the limited low frequency response of the systems of earlier times. How much of the original sound do you want to hear? Pre amps in a goodly chunk of the later mono days often had switchable filters designed for the specific roll off characteristics of the major record labels which would replace the standard RIAA curve in a modern pre amp. Do you want a vintage speaker or a contemporary speaker? Both have their advantages and trade offs. Of course, playing 78's is quite different than playing mono LP's and while one mono system can do double duty a dedicated system for both would be best.

If you do not want a true vintage sound, then, of course, you start with a mono cartridge or a stereo cartridge wired for mono. Stereo record grooves and mono grooves are not the same. Many mono discs have a groove that is too wide for a modern elliptical stylus. Mono discs also only deal with horizontal movement of the stylus where stereo adds the 45/45 vertical ingredient of two channel reproduction.

To minimize groove noise a mono cartridge will work better here than a stereo wired as mono. Look for a pre amplifier with a "mono" button. This lowers the noise floor of any system when playing mono discs. Realize that with the modern RIAA pre emphasis/contour in a contemporary pre amp, the tonal balance you hear will not be exactly as it was intended by the original recording engineer. In the days of mono as the only source available, the typical system had a frequency response that rolled off far sooner than a modern system. To reach 50Hz to 10-12kHz in the days of mono recordings was a very good system. That should easily be surpassed by today's components. With that improvement in response along with a lower noise floor will come some additional information that may not always be desireable. The point of a good mono system today is to play the music and not the noises.

However, a good mono recording is a well made piece of source material. Many of the jazz, pop and blues artists that are so well respected today began their recording careers while everyone still had only mono players. A 78 of Muddy Waters or John Lee Hooker is quite a thing to hear. Miles Davis and Charlie Parker began their recording career before stereo became the norm. In this case, the spatial interplay of those performers can be a very important piece of the recording and a well done mono system today should have a degree of stage width, depth and particularly height. One thing stereo does poorly by comparison to mono is height.

There were no multi-mic/multi-track recordings for the most part until Les Paul began overdubbing in the mid 1950's. Multi-track recordings still didn't catch on for years after that. Still the recordings were made with all the performers together in one room playing together. Often an omni-directional microphone captured both performers and room ambience giving the music a quite "alive" feel when played back on a high quality mono system of today. A good mono system brings back this sense of life that is missing in many of today's recordings and certainly from the "classic rock" days of experimentation with recording techniques.

it is quite sad that more engineers do not check for mono compatibility when engineering/mixing. It is one of the first things I learned apprenticing as a newbie tonmeister, and is the thing that has had the largest impact on the quality of my work..

as for the two speaker-mono thing...the biggest difference is in the perceived balance of the LF information. you get the phantom image and all, but as both loudspeakers are contributing, one gets an exaggerated sense of bass energy. The only way, in my opinion, to listen to mono , is in its native form.. one speaker, baby.. I have a special speaker in an enclosure for this very purpose. nothing ever leaves the studio without first being checked for mono compatibility...if I check/sum to mono and the damn thing collapses..back to the drawing board it is..

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Quote:
Reading Art's notes on mono in the December issue got me to thinking; how would you go about building a decent, dedicated mono system in 2008?

Obviously you can still buy mono phono cartridges, but what would you do next?

The main purpose of such a system would obviously be to play mono lps...

Scott A.
Watertown NY

Buy a true dual mono integrated stereo amplifier with separate power leads for each channel then cut the damned thing down the middle with a hacksaw and attach the spare side panel from the other amp half.............

Something about that reminded me of a recent conversation with my Dad (around 66 I think) and he was saying back in High School his best friend had this nice audio setup that was of course mono- but more than that his friend's father had made these custom speakers- one the tweeter, another the woofer. Talk about getting down to true separates!

About twenty years ago he handed me all his original jazz recordings from back then- many still in pretty decent shape. Dropping those babies on my Rega/Creek/Spica entry high-end system at the time was an amazing experience. after a couple hundred jazz purchases later, I guess it stuck.

My own son is not yet three, but loves pretty much all music and can already tell the difference between trumpet, sax, piano and violin. It'll be nice some day to pass on my collection- although he may have to wait until I'm so old I can't lift the tone-arm off it's rest!

In my experience two speakers generally will not change the sense of depth or soundstaging from a mono source. Unlike with a two channel system when you play a mono recording through two speakers placed in distinct locations in the room your ears are largely still processing the same (identical) information without any other clues being provided about timing relative to a center (mono) image or the other channel. The same would apply to a well recorded stereo source if it were shifted into mono, you would still get a sense of the stage width and depth provided by that recording - just shrunk to a central image. ncdrawl makes a good point that when you "mono" many stereo recordings what you get is sonic mush because of the poor phase relationships between all the multi-mic'd, multi-tracked signals which begin to cancel each other out in selective fashion.

Think of a good FM stereo anouncer's voice, say on NPR. A centered image of the announcer still has depth and a sense of space even though it occupies a tightly focussed position in between your two speakers - ideally it should sound as if it were the voice of someone speaking in your room. The soundfield should be broad and expansive while the "voice" should come from a pin point central position, a spot so tiny as to be the speaker's mouth. That seldom happens in a modern stereo system for many reasons but that is essentially what you should hear.

Now take that centered announcer's voice and replace the close mic'd style of recording with an omni-directional microphone placed slightly in front of the announcer. Suddenly you hear the reflections of the voice off the front, side and rear walls as well as the celing and the floor. That's what you'll get as "spatial" clues in most mono recordings. If a performer stands three feet to the right of the announcer and another performer five feet behind the announcer and slightly to his left, the microphone picks up those reflections from the room and leaves their sonic fingerprint on the recording which your brain then processes to say "three feet to the right". (The famous Mercury Living Presence recordings of the 1950's were made with three omni-directional microphones distributed across the front of the stage and the mono and stereo tracks were cut at the same time. These two versions of the identical performance provide a top notch method of checking just how true your system is between the same source recorded and played in stereo vs. strict mono.)

Obviously the sense of stage width is diminished in a mono recording due to the considerations of how to make a good recording. But within that "confined" central space you will perceive the bass players and horns on the right and the strings on the left just as you would in a stereo recording or in real life. All the images do not clump in the center alone. Bass drums still exist behind the conductor - well behind in most recordings. Just as a good camera provides two dimensional images with a sense of roundness and depth, so too does a mono recording illustrate where performers existed in relation to each other and within the space where the recording was made. While the center image is much tighter on a mono recording, given the proper recording techniques, you could hear someone walk across a room simply because this is how your brain gathers information from the reflected sounds it takes in. It would be somewhat like looking at the event through a pair of binoculars backwards.

The reasons for wanting only one speaker are varied. As has been pointed out, most recordings will suffer some frequency imbalance if two speakers reproduce a source that was meant for mono reproduction. How serious a problem this becomes depends on your speakers and their placement within your room. You do not have the real frequency response of the moment the performance took place anyway with most modern systems reproducing a seventy year old source.

Quite a few people like the sound of the recording played back on the equipment it was meant to be played on. While typically restricted in frequency response the resonances and timbres of the original are well represented. The dynamics offered by a recording that had no electrical compression applied played back with a good triode tube amplifier driving a high efficiency, high impedance field coil speaker in an open baffle can make you wonder just how far we've come in these many years and just what is "progress". The sound of a strictly mechanical playback system can be just as enticing.

So why you choose one speaker or two is something that I find varies with the listener. In most cases two modern speakers will do no more harm to a mono recording than one would but they might not do as much justice to the original source.

Wouldn't that extra, non-essential speaker increase the chance of comb filtering and increase the negative effects of room acoustics on the sound?

I use a dedicated mono turntable with a vintage GE RPX series mono magnetic cartridge (moving iron) to play and dub mono vinyl. The "mono" cartridges currently available aren't "true" mono cartridges, like the Shure M78 or the Grado cartridges, which are actually stereo cartridges combined to mono. The advantage of using a "true" mono cartridge is that it's only sensitive to lateral groove modulation. A stereo cartridge playing a mono record, even strapped to mono, is still sensitive to vertical information, such as dirt and grime at the bottom of the record groove and will reproduce it nicely. A "true" mono cartridge will ignore such junk because it doesn't know about it. Also, it's important to use a 1 mil stylus for mono LPs, as it fits the groove the way it should. A stereo stylus if a tad too small, so it doesn't cling to the groove walls the way the larger stylus will, and the larger stylus can withstand a slightly heavier tracking force than the stereo stylus, resulting in less noise and a more full sounding mono reproduction. That said, if you want to use one of these vintage GE cartridges on a modern turntable, you'll have to get an extra headshell and drill a hole in it for the T-bar that rotates the stylus assembly from LP to 79. One of the nice things about this cartridge is that the two tips are individually replaceable, and you can actually use either two 1 mil styli (one in place of the 78 stylus, or one 1 mil stylus and a .7 mil stylus for later mono pressings that may have been cut with a stereo cutting head (this would include most mono pressings after 1968). The sound I get from my GE cartridge is amazing. It's a full, warm sound with far less surface noise than if I played it with a stereo cartridge with the mono button pushed in on my preamp! You can find used RPX models on ebay, but they don't come cheap, and they don't go bad, either. Stick with RPX and don't go for the later VRII models, as they don't sound quite as full as the older RPX models do.