Mackie Big Knob Studio Issues

[MJKlein]

Stepper attenuator: best option in terms of pairing the two channel levels. Not the most versatile when it comes to fine adjustment. Cost is higher too.

Th behringer studio xl may be worth waiting for if you want standard and usb control in th same package. Send your faulty one back for refund and keep 250 euros on the side for the "soon to come" studio xl.

I agree with that, Patrick. In the meantime I'm going to make the video and ask Mackie to watch it. I'll see what they suggest. At the end of the day though, I might end up having Behringer send me their new one to the retirement home as @pvannatto mentioned, lol. Maybe I can pre-order it.

[MJKlein]

Thinking about the video I need to make to demonstrate the issue, it occurred to me that a better way to ensure a balanced signal source would be to use a single track of tone/noise and route it to 2 channels on the X32, instead of using 2 discreet tracks.

I really wish I could get a video out of the X32 though. Recording the X32 screen with any kind of a camera is a thrash.

[MJKlein]

I recorded 2 tracks each of 100 Hz, 1kHz, and white noise. Each pair of tracks was recorded at the same level and from the same bus using the X32 internal oscillator. The tracks are identical. They are not copy/paste. They were recorded at the same time in real time.

A better way to do this would be to use a single track and route the track to 2 console channels.

[MJKlein]

Did more tests today. It was revealed that the Monitor knob on the X32 ("control room") has issues also. It doesn't track exactly but it's better than the pot in the MBKS. I'm thinking that there is a better solution.

I am considering assigning the L/R main bus to Matrix 1 & 2, and feeding the MBKS from that. Since the MBKS is a volume control, has Mute, Dim and Mono buttons, I really don't need to be feeding it from another monitor control system. I could adjust the trim on the MBKS and also the Matrix pair where they need to be for the input level, and then tweak the right fader on the Matrix for a null, and leave it there. From that point out I would be monitoring a corrected stereo field.

The only major pain would be adding that Matrix setting to the dozens of saved mix files I already have. But that can be dealt with easily enough.

I did find that there was a specific spot on the X32 monitor knob where the test signal nulled, but it was so far down that when I brought up the trim knob on the MBKS to compensate, the issue reappeared. Trying to find a proper level into the MBKS while also being able to null it for a proper stereo field was virtually impossible. At the setting where the stereo field was correct, the LED segments on the MBKS were not lighting at all.

I'm going to make some XLR to TRS cables and try the Matrix solution and see how that goes.

[pvannatto]

Hey @MJKlein , if the matrix solution works, you could make a snippet of the changes, then either load each scene in your console, load the snippet and save each scene. Or you can export your scenes to files. Then use the Merge function of Scene Parser to merge the scene files and snippet and output updated scene files.

[MJKlein]

Hey @MJKlein , if the matrix solution works, you could make a snippet of the changes, then either load each scene in your console, load the snippet and save each scene. Or you can export your scenes to files. Then use the Merge function of Scene Parser to merge the scene files and snippet and output updated scene files.

Paul, my thoughts were that the snippets could be used just as you described. Also, I was thinking that once set, if I use the safes those channels shouldn't be changed when loading other scenes. I only have 2 internally stored scenes; everything else is an AutoMate scene file. Thank you for your valuable suggestions! I'll be getting around to more testing over the weekend.

[MJKlein]

Update:

I made a set of XLR/TRS cables to go from the console to the MBKS and then out to the Adam T8Vs.

I set up a pair of linked Matrix channels to use to feed the monitor controller. That way I could use the sends from the L/R bus to feed the Matrix pair and make balance adjustments as necessary. I was rather surprised when I hooked everything up, checked the levels with my test setup and was able to get a total audio null out of the monitors when pressing the Mono button on the MBKS device.

Encouraged by not having to make any matching adjustments to the Matrix sends, I then tried using the main L/R outputs as normally routed to XLRs 15/16. Again, I was able to achieve a complete null with both channels exactly at 0.0 dB. That means the issue was not with the MBKS. My balanced cables seem good and I'm not using the X32 monitor section at all. The levels into the MBKS are perfect, and I've adjusted the T8V levels with white noise for a balanced stereo field. It seems that all is well and everything sounds perfect. A set of B monitors has confirmed the stereo field is very good.

This was an excellent lesson on not jumping to conclusions and starting to blame something too early on in the testing process. While it was natural to assume that the monitor controller was off, it turns out that there were other factors to consider also. I'm not ruling out the cables I was using before I fabricated my own. I'm going to keep the MBKS and I feel at this point there is no need to make a video, unless it's to vindicate the device.

[pvannatto]

Glad to hear that you figured it out finally, @MJKlein . Of course jumping to conclusions and blaming something (or someone) else seems to be the norm these days, especially for past presidents...

[MJKlein]

Of course jumping to conclusions and blaming something (or someone) else seems to be the norm these days, especially for past presidents...

Off Topic

Not just presidents, and not just past ones. Blame is an amazing concept that I have to live with in this society, daily.

[RexBeckett]

Weird issue to have been caused by cables.

I did once have an odd problem resulting from a balanced XLR to unbalanced jack cable where XLR pin 3 was not tied to pin 1. The servo-balanced output stage changed its output level dramatically according to the input impedance of the driven device. That is predictable behavior for many servo-balanced output designs but it took a while to spot!