Rear input no longer auto?

[Morbid]

Hey Gang.
Love my XL+, but recently experienced something odd.

EDIT: Chris pointed out the error of my ways on the first issue, so to make this easier now,

I have my I/O Setup as
Main Input Source: Analog (1)
Input 1 Left select: Front
Input 1 Mode: L+R Sum

This allows me to have a cable plugged into the front when needed, and able to use my wireless with it being plugged into the rear, without having to swap any settings or deal with any cable mess.

But I've noticed, when set to L+R Sum, the input source levels are much weaker. I can turn the inputs all the way up to 100% and still not clip, but if I select Left Only, I can turn Instr In down to about 8:30 and Input 1 down to about 11. I noticed THIS on the same day, because my Wireless signal sounded weak on my high gain settings, like I had the volume knob on the guitar turned down. Once I cranked Input 1 level in the I/O panel, everything was kosher.

Any idea why this would be?

Appreciate the help, folks.

 

[chris]

The Axe2 was never auto. The Axe3 is.

Maybe you had the wireless in Input 1 Right rear, but now you don’t.

 

[Morbid]

The Axe2 was never auto. The Axe3 is.

Maybe you had the wireless in Input 1 Right rear, but now you don’t.

It would appear that you were absolutely correct and I am simply an idiot. Thanks for the correction!

Still curious about why the input level drops so much when in L+R Sum though

 

[GiRa]

Because you get only half of the signal in.

EDIT: you could add a block boosting the signal by 6dB and likely get the same signal level into the grid but you would be boosting a signal coming from converters not working at their best.

 

[Morbid]

Because you get only half of the signal in.

EDIT: you could add a block boosting the signal by 6dB and likely get the same signal level into the grid but you would be boosting a signal coming from converters not working at their best.

Interesting. Do you think there would be a big enough difference in tonal quality to justify switching back and forth in the I/O rather than how I have it set now?

 

[GiRa]

No idea. Try and see.

 

[Bakerman]

The converters will be working fine but noise from the unused input gets added to your signal if you're always summing L & R like that.

The level drops by 6 dB because Sum L+R input mode puts (L+R)/2 in both channels, instead of L in both channels or L in one, R in the other. Except, unity gain compensation never worked properly with Sum L+R input mode and front Instr input as left channel. Adjusting the front input value affects the level of that signal in the right channel reaching the grid, same for Input 1 (R) adjustments and left channel grid level, unless you set one value to produce the same post-DA adjustment as the other. Setting the Input 1 value about 10-15% higher than the Instr In value will be approximately correct.

But I've noticed, when set to L+R Sum, the input source levels are much weaker. I can turn the inputs all the way up to 100% and still not clip, but if I select Left Only, I can turn Instr In down to about 8:30 and Input 1 down to about 11.

Changing the input mode doesn't add headroom. The LED meters indicate level after the (L+R)/2 process so the red LED will never light from either signal alone with Sum L+R input mode selected. (Playing through both inputs together could still potentially hit red.) Switch Input 1 Mode to stereo temporarily if you want useful LED metering when adjusting Instr & In1 levels.

 

[Morbid]

The converters will be working fine but noise from the unused input gets added to your signal if you're always summing L & R like that.

The level drops by 6 dB because Sum L+R input mode puts (L+R)/2 in both channels, instead of L in both channels or L in one, R in the other. Except, unity gain compensation never worked properly with Sum L+R input mode and front Instr input as left channel. Adjusting the front input value affects the level of that signal in the right channel reaching the grid, same for Input 1 (R) adjustments and left channel grid level, unless you set one value to produce the same post-DA adjustment as the other. Setting the Input 1 value about 10-15% higher than the Instr In value will be approximately correct.


Changing the input mode doesn't add headroom. The LED meters indicate level after the (L+R)/2 process so the red LED will never light from either signal alone with Sum L+R input mode selected. (Playing through both inputs together could still potentially hit red.) Switch Input 1 Mode to stereo temporarily if you want useful LED metering when adjusting Instr & In1 levels.

Bakerman! Haven't seen that name since back in the old Petrucciforum days. If you are the Bakerman I believe you to be, I hope life has been treating you well, my friend!

I really appreciate the thorough explanation. This makes a lot more sense now, and while admittedly not as convenient, I think this will talk me into going back to LEFT/REAR and just switching as needed.

Thanks again!