clipping w/o clip indicator...HELP! thanks...

[jeffmitchellmusic]

Hi All,
First post here.  I've been using the Micro-BR for a couple of years now and have had some success.  Picked up a new problem.  I'm getting distortion on input signals when they get just past the halfway mark on the level indicator.  No clip light or anything.  It should be well within the recording range.  It sounds lousy!  Any thoughts?
all the best, Jeff
p.s. it's not just the onboard mic.  the guitar input is doing it as well.  haven't checked for it on the line input yet.

[hewhoiscalledj]

how are you monitoring? check the headphones or speaker outs, or check a mastered song on another system to see if the distortion carried over into the recording itself... yikes.

[jkevinwolfe]

Jeff,

You on batteries or AC? I have heard elsewhere that people have had issues with weak batteries causing distortion. I use lithium, which are outrageously priced but give lengthy performance and then just kind of croak. I'm guessing that a faulty AC adapter could have the same effect.

Also, I have noticed that sounds below the clip indicator threshold can start to sound somewhat distorted, depending on their abruptness and other characteristics. You might also check the input volume control on the right and the sensitivity. Generally I run the input knob at 85 as I have noticed a little distortion in some inputs when I have run it at 100.

What effect are you using when you get distortion? The mic effects shouldn't distort, but if you run the mic through a guitar effect, it typically does.

[Glenn Mitchell]

Then there is the old forgetting to shut off the FX during playback. Not so likely with a experienced user but I still do it occasionally.

[Flash Harry]

Is there any DC offset on your inputs? This could cause it.

[jeffmitchellmusic]

Wow you guys.  Thanks for all the input.  What a great community.

I've been testing things as I'm writing this and here's the most conclusive thing I've found.  The line input seems fine.  I've got an FMR preamp hooked up to the line input with a Y cable.  Dynamic mics, condensers, and the DI on the preamp all were distortion free through the line input.  It's the onboard mic and guitar input on the BR that are both giving me distortion.  So there's that.  Here's the rest of what I've found...

Ok, so I converted a test track to MP3 and put it on the computer.  The distortion is still there so I guess that rules out the headphone output.  I recorded my test with the input wheel at 85, still clipping with no clip light and well within the recording range on the meter.  I've tried it with fresh batteries (NiMH), old batteries, and a Onespot adapter, all with the same distortion.  I'm recording and listening with all effects turned off, no reverb.  I'd never heard of DC offset before your post Harry, so I looked it up.  Here it is from Wikipedia...

"DC offset is an offsetting of a signal from zero. The term originated in electronics, where it refers to a direct current voltage, but the concept has been extended to any representation of a waveform. DC offset is the mean amplitude of the waveform; if the mean amplitude is zero, there is no DC offset.

DC offset is usually undesirable. For example, in audio processing, a sound that has DC offset will not be at its loudest possible volume when normalized (because the offset consumes headroom), and this problem can possibly extend to the mix as a whole, since a sound with DC offset and a sound without DC offset will have DC offset when mixed. It may also cause other artifacts depending on what is being done with the signal.

DC offset can be reduced in real-time by a one-pole one-zero high-pass filter. When one already has the entire waveform, subtracting the mean amplitude from each sample will remove the offset. Often, very low frequencies are called "slowly changing DC". While not technically accurate, a high-pass filter can remove such a "changing offset" better because its cutoff does not extend to as low a bandwidth as the above method."

After all that, I'm certain I still don't understand DC offset, but at least it's a start.  It seems like a possibility because the level on my BR shows above zero if I've got any reasonable recording level dialed in on the input wheel.  There's also a very audible hiss in a quiet room.  I know this can be a regular feature of condenser mics, but it seems loud to me.   I don't know what a "one-pole, one-zero" high-pass filter is, but I tried the "AG LoCut" effect, which I assume qualifies as a high-pass filter and that didn't help. 

Again, thanks for all your input everybody.  Hope I can get this thing back in fighting shape.
all the best, Jeff

[hewhoiscalledj]

So you arent getting any of the distortion you speak of when your mics are going thru the external preamp... and it's only the guitar in and built-in mic that's getting the distortion; even though you don't get the OVER signal and the levels are within range.  Hmm... that is strange.

While recording, the INPUT wheel doesn't actually do much and it's the SENSITIVITY level that matters the most (on the INPUT screen.) But the fact that the levels aren't topping out makes me think something else has to be wrong (like an impedance mismatch) What are you connecting into the Guitar In that is getting distorted? Is it a guitar? I would hate to consider the chance that it's the Guitar Input that's "jacked" up but it's a possibility. You mentioned getting the same problem with the built-in mic so it's even harder for me to believe that there are 2 connection issues... usually the simpler answer is the right one, so perhaps it's the original signal (guitar, mic, whatever...) or (and don't take this the wrong way,) it could be user error. I hope that's all it is because otherwise, the little wonder box could need repair.

I hope that all made sense to you. Good luck and keep an eye out for 64G's response... He's way ahead of our learning curve with this stuff.

[64Guitars]

Can you verify that the OVER indicator is working? Increase the input sensitivity and see if the OVER indicator lights. If it never lights, then your input signal level is probably too high but you're not aware of it because the OVER indicator isn't working.

Are all six segments of the Input level meters working? If the top segments were dead, you wouldn't know that your recording level is too high. It's unlikely, but worth checking.

Do you hear the distortion while you're recording, or only on playback of the track?

What happens if you reduce the input sensitivity to minimum and turn down your guitar's volume control a bit? Do you still get distortion?

You said that you've had the Micro BR for a couple of years. If this is the first time you've had this distortion problem and you can find no explanation for it, then it could be that some internal component has failed and you'll need to send it to Roland for repair. I think someone else here had a similar problem a while ago and had to get their Micro BR repaired, although I can't find the message thread now.

What happens if you reduce the record level so that only the bottom 1 or 2 segments of the level meters light, and the input sensitivity is set at minimum with the guitar turned down a bit? Can you still hear distortion? If so, then I think that's a good indication that your Micro BR is in need of repair.

[tackium]

We become pararnoid when the BR hits the floor. I "noticed" this hypersensitivity issue on mine after a fall too. My "over" light did show up though. I lowered the sensitivity, lowered the amp volume, lowerd the input. I never thought of lowering the guitar volume for some reason though,I did shake the BR near my ears to make sure nothing rattled, it didn't. But the blow was severe enough to make the BR not see the card for a while, I had to take it out  and put it in again...etc. etc., gave up for the day thinking the worst.
The next day I noticed I was trying to record clean with my raudiest guitar. High output hum buckers. I tried it again with the ol' strat and the problem was gone. Once I was calmed down it was ok I plugged the humbucking devil again and found suitable setting for it to sound reasonably clean. It was also a different room, at a different place. It is possible a computer monitor nearby spoiled the signal the day before.  So my advice is , try it with other guitars, in different environments before declaring the thing broken.

[jeffmitchellmusic]

Thanks again.
Ok.  So the "over" indicator definitely is working, as well as the level meter.  All of the lights are functional.  I hear the distortion both recording and playing back, including exported files played on the computer.  Turning down the guitar volume isn't the issue as this happens with both the mic input and guitar input, same distortion.  Also, no hot humbuckers for me, only single coils.  The distortion is a new thing as far as I can tell and it does go away at very low input levels. 

64G, I think you are probably right on the money saying it probably needs to be serviced.  My brother has one I should be able to borrow for a bit if I need to send it off.  Anyhow, thanks all.
cheers, Jeff