fix for left channel

[Jeff Hodges]

I read some time back that the left channel on the PC monitoring section was hotter than the right...I guess I've been living with it but yeah, if I turn the volume down so that it is barely audible then just the left channel plays...

What is the fix for this? I have 5.1.1 and the latest drivers loaded over, etc.

[jackruston]

Some people have reported problems with the main pot. Digi will send you a new one asap if you give them a call. The main thing to note is that these pots are not all that great anyway, and will only really be happy in the middle of their range. If you turn them right down low, you will get stereo wierdness and perhaps some audible distortion. They are fine at 12oclock. If you do want to monitor at very low level, and can not adjust your speakers, I would recommend building yourself a passive step attenuator. You just get a balanced stereo attenuator from a hifi manufacturer (Dact make an amazing one but it costs) and wire it up to four xlr sockets. Use the best wire and solder available. You can use it to attenuate any signal in tiny increments with a very pure signal path. It's a useful tool to have around.
If you have a look at a few of the threads about the pc monitoring section you'll see that opinions are a bit mixed. I for one believe that it really could be better, but it doesnt stop me going to work every day. [img]images/icons/smile.gif[/img]
Jack

[Jeff Hodges]

Jack, thanks for the response.

Yeah, if I have the volume down to just over zero, it only comes thru the left channel. if I switch to mono, however, i get equal signal out of both.

I'm not much of an electrical engineer tho! [img]images/icons/wink.gif[/img] )

[jackruston]

The manual does actually state that the pot is not going to perform well at it's extremes. The great debate has always revolved around the cost of the unit and why the pots are ropey at that price...

You really dont have to be that great an electrical engineer. It's a question of following a simple wiring diagram and handling a soldering iron. See if you can get someone to help you out if you are unsure. You can ususally order a small case with xlr socket holes punched. You just drill a hole for the shaft of the attenuator and bob's your uncle. I was lucky because my brother works in electrical manufacturing and he helped me get it sorted. They've got a lathe down there, and I made my own control knob. It's aluminium, and about 4 inches accross/4 deep. Completely ridiculous. People always ask me what it is when they come in. If it's an engineer I give them my passive attenuator lecture and they pretend to find it interesting. If its a money man, I tell them it's an amazing unique audio processor with 43 russian military valves inside. They love all that bollocks. [img]images/icons/smile.gif[/img]
Jack

[Stan Cotey]

Hi all,

I wanted to provide a little background information. First off, this is not a fixed gain "error" so some units will display this at extreme low level settings (on either channel) while many units won't show as much error. What's going on is, the analog monitor pot has a particular tolerance, which all analog pots have. The problem comes in when you stack six sections of pots together to allow surround work. Each section can be off from the others by the tolerance error of the pot. The actual pot is custom made, very high quality, and costs us over $60, versus the type of controls that one might find in a commodity type product, which may cost under a dollar.

At the time that ProControl was coming out, the only level control options were; use a pot, which yields high sound quality but not great channel-to-channel matching at the extremes; use an electronic attenuator (either a VCA or MDAC circuit), which has great channel-to-channel matching but is not so hot on transparency; or use a passive attenuator, which would have raised the list price significantly given ProControl's surround monitor capability. We chose a high-quality pot to preserve sound quality while being reasonably cost effective.

The monitor pot in ProControl should offer very good imaging across the control range of 9:00 to 3:00. We suggest optimizing your monitor system amplifier gain so that you mostly work in that range.

All linear pots add some type of distortion but it should not be audible.

I hope I've answered your questions but if not, let me know or write me privately at: [email protected].

Regards,

Stan Cotey
Product Manager

[speedyk5]

Hi
i've just install my new PC and my new speakers and i'd like to say that sounds great!No distortion no imaging problems!

[jackruston]

Thanks for your input Stan. I didnt realise that surround capability makes life so complicated.
Jack

[Stan Cotey]

No problem Jack, and thanks for your input as well. I'm a big fan of passive attenuators but the cost gets pretty high for multiple channels, especially if they are balanced. For a 5.1 signal, you're basically talking about a 12 deck, 24-position or better rotary switch with gold (or better) contacts -- hundreds and hundreds of dollars by the time you throw in a few hundred precision resistors and some build labor! Also, you have to be careful when specifying a passive attenuator. They require a specific known input and output impedance to work correctly. Since ProControl has to work with anybody's DAC, CD player, etc. as an input source and drive anything from a 600 Ohm balanced or unbalanced device to a 10 kOhm unbalanced device, it just wasn't a valid choice. We would have had to include a disclaimer "Warning! For lowest distortion and most accurate gain control...", which probably wouldn't have gone over too well.

Cheers,

Stan Cotey

[jackruston]

Hi Stan
I totally understand why that has to be the choice. I suppose the difficulty with having a system that is industry standard for quite a wide range of industries...anything from tv commercials, to rock bands, to film pp, is that you always have to compromise in some ways to include the features the majority want. Pro tools stretches accross these industries in a way that other daws do not. OK so my ideal monitoring section would be stereo, but a film pp house will always need surround... Most of the people on the DUC are pros, paying pro prices, and hoping to achieve their own ideal system...eventually! Of course there are some features that we all want and will always bug you for, but thats all part of the process. In an ideal world, my pc monitoring section would be different, but I accept that it isnt, and why. Cheers Stan
Jack