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Today I recieved my MoCo, a monitor controller from the German manufacturer Esi. It is passive and can handle two stereo sources and two pairs of monitors.

It sounds very neutral, and is extremely quiet. It also has L/R swap functionality, mute and mono. Two things to consider: it has no status lights whatsoever and the housing is made of sturdy plastic.

http://www.esi-audio.com/products/moco/

Comments

audiokid Wed, 12/27/2017 - 14:43

Kurt Foster, post: 454748, member: 7836 wrote: i've read that this is a problem with passive monitor controllers but not active. the image will shift as you turn the volume up and down especially at lower levels.

Exactly where I am going with this. Could be that this build is better or miyaru hasn't had it long enough to start noticing this. Lets hope its a good design as it looks good.

audiokid Wed, 12/27/2017 - 14:49

Kurt Foster, post: 454750, member: 7836 wrote: actually, i believe it was Boswell who wrote that. i understood it as an issue with all passive summing.

I believe you are correct. But its also why I ended up sticking with the Dangerous Monitor ST for my last hybrid system. We've had a few discussion about passive monitor controllers over the last decade and I'm looking for one thread in particular that really explains it all. I believe Bos chimed in on it.

audiokid Wed, 12/27/2017 - 15:03

Here is the post I was thinking about but there are a few good ones where Boss explains much more.

https://recording.org/threads/event-opal-monitors.54150/page-4

ChrisH, post: 431305, member: 43833 wrote: Radial Monitor Controller Update:

After testing the controller in greater detail, I noticed that I wasn't crazy and when you attenuate the volume down to 75 or lower db the disbursement to your left and right monitors becomes imbalanced :( Left monitors being louder than the right.

So... if I can't fix that, I've gotta move on, I believe my best option for what I want out of a controller is the SPL MTC.
Didn't @audiokid own the MTC?

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Boswell Wed, 12/27/2017 - 15:33

Since that previous thread I've fitted a 40dB toggle switch to my SM Pro passive monitor controller specifically to deal with the problem of image drift when listening at low volumes.

audiokid Wed, 12/27/2017 - 15:43

Boswell, post: 454754, member: 29034 wrote: Since that previous thread I've fitted a 40dB toggle switch to my SM Pro passive monitor controller specifically to deal with the problem of image drift when listening at low volumes.

image drift when listening at low volumes. Well defined!

audiokid Wed, 12/27/2017 - 15:50

Boswell, post: 454754, member: 29034 wrote: Since that previous thread I've fitted a 40dB toggle switch to my SM Pro passive monitor controller specifically to deal with the problem of image drift when listening at low volumes.

Bos, which do you have and how much are these? I've never heard of this company. http://www.smproaudio.com/index.php/en/products/monitor-controllers

audiokid Wed, 12/27/2017 - 15:56

@miyaru
My apologies, I don't mean to be hijacking your thread or detracting away from something you just bought and should be thrilled about. We're always dissecting pro audio around here and I am the worst of the bunch when it comes to researching and hashing through it all. Again, my apologies, hope you are listening close to the imaging (for image drift) and report back any findings.:)

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miyaru Wed, 12/27/2017 - 20:09

Yeah, will do that..... Most of you guys/girls here are pro's. I'm just an enthousiastic in recording stuff. Does not say I'm not serious, but because it is not my way of making money, my budget is tighter than most of you overhere.

I will report back, and the - 40db switch could be a handy thing. Before the MoCo, I was adjusting the volume on my audio interface, but it adjusts volume in the digital domain. So playing at low levels thins out the bit depth of your signal then, wasn't handy too......A thing to consider!

At first I was looking for a Presonus Central Station Plus ( https://www.presonus.com/products/central-station-plus ), but these are hard to get second hand for a nice amount of money though. These are passive too, but seem to do it good. And also the thought that you heve a remote cable over your desktop instead of a bunch of cables. But my current setup just doesn't justify the purchase of such a device. It would be more expensive than my monitors. (which are from Presonus too - the Eris E8).

audiokid Wed, 12/27/2017 - 20:38

Cool,

Generally speaking here: Learning about what gear does shouldn’t ever be about money. We all have a budget and get what we can afford but that should never get in the way of learning and passing on what we discover along the way!

Some very inexpensive tools work awesome just as some very expensive products actually suck. In fact, I have actually paid a lot of money for analog products that don’t do near the job inexpensive software does much much better on a computer.

The thing to be aware, that we aren’t buying something that is actually fooling us or screwing us in other ways.

Here’s to having thick skin in this business!!!

Cheers!

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Boswell Thu, 12/28/2017 - 02:49

audiokid, post: 454756, member: 1 wrote: Bos, which do you have and how much are these? I've never heard of this company. http://www.smproaudio.com/index.php/en/products/monitor-controllers

I've had an M-Patch 2 ever since they first came out. That model was the one that escaped before SM Pro Audio found their tin of red paint.

I also have a couple of their original Nano Patch units that I often use for inserting between mixing desk and power amps when I'm doing PA on live recording gigs. In addition to doing level matching, the Nano Patch is like its bigger siblings in having a handy mute button.

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DonnyThompson Thu, 12/28/2017 - 03:16

Boswell, post: 454754, member: 29034 wrote: Since that previous thread I've fitted a 40dB toggle switch to my SM Pro passive monitor controller specifically to deal with the problem of image drift when listening at low volumes.

So...i don't have a controller, but I'm really intrigued by this...so be patient with Donny the moron for a min, LOL...how is the toggle implemented? Meaning, is this something you use in place of the actual volume control, like a pad switch? And it corrects the disparity you noticed in the stereo image when gaining down for lower listening levels?

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Boswell Thu, 12/28/2017 - 04:48

The problem with standard multi-gang anti-log pots is that, at the lowest resistance end, it is very difficult to get precise mechanical (and hence resistance) matching between gangs. At the low end of a 10K pot, one gang may be reading 10 Ohm (-60dB) while its neighbour may be 20 Ohm (-54dB). That 10 Ohm difference creates a 6dB differential in output level between channels. The relative resistance difference at the higher end creates less level difference, even allowing for the log encoding. This means that adding a 40dB pad ahead of the pot for low-level listening brings the operational range into the higher end of the pot where the mechanical matching tolerance causes much less signal level difference.

The toggle switch (4-pole for balanced stereo signals!) is indeed like a pad on a microphone. However, the resistance values have to be computed carefully to achieve a compromise that allows not only for the loading of the variable pots on the pad but the loading of the loudspeaker inputs on the variable pot.

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DonnyThompson Thu, 12/28/2017 - 05:23

Boswell, post: 454772, member: 29034 wrote: However, the resistance values have to be computed carefully to achieve a compromise that allows not only for the loading of the variable pots on the pad but the loading of the loudspeaker inputs on the variable pot.

And how is that calculated? Presumably there's a concrete set of figures that define that, but you also mentioned "comprise"... And is that accomplished simply by listening?
I think it's quite fascinating that some passive controllers have this 6db difference at lower levels...I mean, I mix at 73-75db all the time, it's probably my most-used volume level, not counting periodic checks at higher levels (FM Curve), but those higher levels aren't common for me for mixing sessions. This DB difference seems dramatic to me... I'm trying to picture in my head mixing at 74db with one half of my stereo field being shy (or gained up) 6db,... It would drive me crazy!
I know you have an extensive history of electronic and technical design, pal...have you ever mentioned this disparity to any of the companies who make the models affected? I dunno...I might be overplaying this - or quite possibly misinterpreting it - but this sounds like a pretty big issue to me. Obviously it bothered you enough to design a circuit fix for it.. so it can't be all that small of an issue, no?
Or am I missing something? (Which is certainly possible, LOL ;) )
-d.

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Boswell Thu, 12/28/2017 - 07:56

DonnyThompson, post: 454774, member: 46114 wrote: And how is that calculated? Presumably there's a concrete set of figures that define that, but you also mentioned "comprise"... And is that accomplished simply by listening?
I think it's quite fascinating that some passive controllers have this 6db difference at lower levels...I mean, I mix at 73-75db all the time, it's probably my most-used volume level, not counting periodic checks at higher levels (FM Curve), but those higher levels aren't common for me for mixing sessions. This DB difference seems dramatic to me... I'm trying to picture in my head mixing at 74db with one half of my stereo field being shy (or gained up) 6db,... It would drive me crazy!
I know you have an extensive history of electronic and technical design, pal...have you ever mentioned this disparity to any of the companies who make the models affected? I dunno...I might be overplaying this - or quite possibly misinterpreting it - but this sounds like a pretty big issue to me. Obviously it bothered you enough to design a circuit fix for it.. so it can't be all that small of an issue, no?
Or am I missing something? (Which is certainly possible, LOL ;) )
-d.

I only used 6dB as an example because it make things more evident where the numbers came from. I would be surprised if any decent passive monitor controller were as far out as that anywhere in its travel. Having been involved some time ago in the commercial design of a multi-stage switched attenuator, I know it's one of the compromises a manufacturer of the continuously variable type has to accept, unless cost is no object.

The usage instructions of some rotary passive attenuator units give matching figures between channels, usually specified as a small dB difference, but crucially usually only over the first 40 - 50dB of attenuation.

I think the point is that the continuously variable types are not meant for serious use at high attenuation levels, which is why I added the "pad" switch to the unit I have. The pad resistor value calculations are not difficult - just the usual pair of simultaneous equations. The tricky bit comes in deciding what trims to make to the resistor values to best adjust for the variable loadings.