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mike1762
Senior Member
Username: mike1762

Post Number: 985
Registered: 1-2008
Posted on Thursday, March 28, 2013 - 5:59 pm:   Edit Post

I run my bass into a Boss GT-10B with the Left balanced output going to my amp (QSC) and the Right balanced output to the board. I've noticed that I'm clipping the hell out of the board (mainly when slapping) despite turning the trim all the way down (I have as much compression on it as I can without it starting to sound "squashed"). If I turn the output (or input sensitivity) down low enough that it's no longer an issue, I can't hear my amp. I plugged the output into my studio board (ProSonus 16.4.2) and it wasn't a problem (and the trim was at about 9 o'clock). My "live" board is a Chinese made German product (I'm too ashamed to type the name). What is going on here... it's obviously some sort of technical issue.
sonicus
Senior Member
Username: sonicus

Post Number: 2836
Registered: 5-2009
Posted on Thursday, March 28, 2013 - 6:34 pm:   Edit Post

Try padding down at the input stage of the clipping board. In the signal path going to the " clipping problem " board put a Limiter inline and adjust it accordingly to your desired results. Limiting is different sonically then compressing. Slapping a bass produces extreme transients over a relatively wide bandwidth . There are multispectral variations possible with various compressors as well as limiters that allow you to adjust the gain of the frequency or frequencies that you desire to attenuate.
sonicus
Senior Member
Username: sonicus

Post Number: 2837
Registered: 5-2009
Posted on Thursday, March 28, 2013 - 6:40 pm:   Edit Post

Careful gain structure attention is paramount to faithfully reproduce slap bass technique. Building headroom from the beginning to the end of the signal path is King.
mike1762
Senior Member
Username: mike1762

Post Number: 986
Registered: 1-2008
Posted on Friday, March 29, 2013 - 2:26 am:   Edit Post

I understand that approach... but why are the 2 boards reacting so differently to the same signal? I thought I understood the concept of "headroom", but maybe I don't. I think of it as the capability of an amplifier to produce short-term signal peaks without distorting. Can the input stage also have "headroom"???

I hate the compressors that are "built in" to the GT10B (you can't adjust the parameters), so I was considering putting a MXR M87 Bass Compressor in front of the GT10B: the M87 has an adjustable attack and release, so I could use it to tame the transients on the front-end (hopefully without any pumping/breathing)... is there any particular advantage to doing it on the back-end (as you suggested)?
cozmik_cowboy
Senior Member
Username: cozmik_cowboy

Post Number: 1442
Registered: 10-2006
Posted on Friday, March 29, 2013 - 9:35 am:   Edit Post

"....why are the 2 boards reacting so differently to the same signal?"

Well,

"My "live" board is a Chinese made German product...."

That would probably explain the problem.....
(Are we talking the "B" word here? )

Peter
mike1762
Senior Member
Username: mike1762

Post Number: 987
Registered: 1-2008
Posted on Friday, March 29, 2013 - 11:28 am:   Edit Post

The "B" word indeed. Honestly, I've had very good luck with their gear. But this may be an example of a subtle deficiency that may not be immediatly obvious. I'm probably going to start using the ProSonus live again and just use the Behringer for rehearsal. I have the ProSonus in a rolling rack, so it's not that big of a deal to swap between live and studio use. So back to my question: is there "headroom" associated with the input stage? If so, that would explain why the Behringer clips so easily as compared to the ProSonus.
mike1762
Senior Member
Username: mike1762

Post Number: 988
Registered: 1-2008
Posted on Friday, March 29, 2013 - 1:01 pm:   Edit Post

I did a little bit of reading and answered my own question: "Yes". I honestly don't understand the physics very well, but just knowing that you can have "headroom" issues ANYwhere in the chain explains a lot. Basically, when you exceed your "headroom" you get "clipping"... correct??? Recently I noticed that I was getting distortion when running some FB supressors as channel inserts. If I removed them the distortion went away. I now realize I was clipping the FB supressors before I was clipping the channel (the channel on the board had higher "headroom" than the FB Suppressor... correct?). Maybe I wasn't having as good luck with the Behringer gear as I thought!!!
flpete1uw
Intermediate Member
Username: flpete1uw

Post Number: 164
Registered: 11-2011
Posted on Friday, March 29, 2013 - 1:39 pm:   Edit Post

All Consoles act, sound and clip at different ways and limits. Is the Board Class A Electronics like an old Neve? (Ahh 8048,8058,8068) or a newer ones with subpar chips. Just like Alembics (In my opinion) sound better than any other Bass. I guess what Iím trying to say itís all about the Signal gain structure from start to finish. Itís what makes an Audio Engineer part Art part Engineer. Each part has to be in the sweet zone from start to finish. Bass out, Line In, Fader to 2 mix. Etc.etc.etc. Itís not too hard just go through the signal path one step at a time. Itís all in the electronics.
Hope this was a little helpful
Pete
sonicus
Senior Member
Username: sonicus

Post Number: 2838
Registered: 5-2009
Posted on Friday, March 29, 2013 - 4:43 pm:   Edit Post

Pete , I love those Neve's !

Mike , ___ Does the offending board ( the B word ) have a -10dBv & +4dBu setting for gain standards ? That could be part of the problem . If it does ; set it for +4dBu and see what happens . Perhaps you have found the flaw in the signal chain as you explained with the inserts and the FB suppressors. A limiter in line there might help as well . Inserts on less expensive boards often have headroom problems.

Wolf

(Message edited by sonicus on March 29, 2013)
mario_farufyno
Senior Member
Username: mario_farufyno

Post Number: 908
Registered: 9-2008
Posted on Saturday, March 30, 2013 - 11:12 am:   Edit Post

Mike, you can trim down GT10B output to tame excessive gain, but remember that compression doesn't mean chop off peaks necessarily. Limiters are more apropriate to deal with transients since they react more quickly to incoming signal exceding the threshold. But keep in mind that a bad attack setting can sound like a kind of distrotion, too.
jzstephan
Intermediate Member
Username: jzstephan

Post Number: 158
Registered: 1-2012
Posted on Saturday, March 30, 2013 - 1:00 pm:   Edit Post

If you're running a balanced line level signal out of your preamp into your mixer's xlr mic input, it will clip.
mario_farufyno
Senior Member
Username: mario_farufyno

Post Number: 909
Registered: 9-2008
Posted on Saturday, March 30, 2013 - 1:03 pm:   Edit Post

Let the compression away for a while. There are some important considerations to do first:

Sound Pressure as perceived aparent volume depends on your cabinet's efficiency to convert the power of an Amp in air motion by a Loudspeaker. So, if you want more "volume" you need a better cabinet first and more powerfull amp second (the main factor still is your cabinet's sensitivity). Or you must have an individual bus out to feed your own stage monitor at least...

An Electric Bass doesn't makes sound, it produces an electric signal that translates (or describes) string's motion. That signal is very weak and needs to be amplified several times before being able to push a heavy loudspeaker's cone.

But this signal changes over time, first it pumps a very quick unorganized energy burst called Transient. It happens when we first release the string and it strongly starts to vibrate, expressing the initial attack of a note. It is so quick and shows so many stacked frequencies that we can't recognize pitch, tone or volume, just the snap or kick feel.

After that initial bounce, the movement gets more stable and we can finally recognize pitch and volume. In fact, we can't feel the exact power of each fluctuation on pressure since they occurs so quick, we perceive loudness by a kind of average of this oscilations called RMS (root mean square). So, in a Bass signal we have 2 meaningful data: peak level and average sound pressure level.

The first is important mostly to our gear, since excessive signal can harm some components, but clipping can chop off peaks and change the transients affecting an important part of the tone, too. On other hand, we're used to be more sensitive to loudness, so we focus on pushing volume up until sound pressure feels right.

The problem is that a Bass can produce Transients many times stronger than its "average" level and an audio gear must accomodate both. So, if the average is on a good level (nominal level - 0VU) the peaks will be probably got clipped, but if peaks are safely under clipping level the average will be most probably much under proper level (since too low levels always result in too much electrical background noise contamination during further amplifying steps). This is a headroom issue because headroom is how much signal one gear can deal with above its optimun level (0 VU) without clipping. A quality console can give you more than +20dB above 0VU to reproduce peaks properly, but cheap ones doesn't and this can be a real problem when reproducing a Bass.


This is the only reason to control dynamics, but you must be aware that any changing in wave format is distorting it, too. So, attenuating peaks means deform tone's envelope and tone. For example, if you use too long attack settings on your compressor, it will not affect transients and will increase level discrepances between peaks and average. If it is set too quick, it will rip off any peak and this'll make the bass sounds rubbery and floppy (compromising its percussive character). So, it is very difficult to properly adjust a compressor and very easy to mess it all.

Even knowing the B stuff are limited in many ways, it is not normal one having to choose between clipping or hearing. Did you ever tried without the GT10? Don't know but may be this compression set is worsening your problems. Extreme Eq settings always mess things up, too, when we try to equalize the room on the instrument instead on the PA/FOH. Many experienced musicians forget that the sound on stage usually is totaly different from FOH and we can't Eq directly on Instrument unless our reference response would be perfectly flat at our listening position (and they never are). Imagine yourself monitoring your bass tone in a tiny 10" speaker cabinet and trying to compensate its lack of bass, while sending that very same signal to a gigantic PA system equiped with thunderous 18" subwoofers. This mismatching always causes troubles and keeping things simple is a good way to avoid problems.

Try to test what happens discarding the compressor. Try swith off any amp simulation (you just need these when recording in a bad room). Don't adjust your monitor's tone on GT10 if it is not the "PA", it must be done at the console aux or bus out (some small venues uses just the Amp to feed public, but in this case we must equalize from audience perspective, not at stage). If your problem is peaks, prefer to use a Limiter instead of a Compressor. Avoid using too fast attack, is important to keep at least some part of the transient to preserve tone. If GT10 doesn't helps you to control attack and release settings, try another modeled gear (different brands and models naturally have different attack and release times)
mario_farufyno
Senior Member
Username: mario_farufyno

Post Number: 910
Registered: 9-2008
Posted on Saturday, March 30, 2013 - 1:06 pm:   Edit Post

too confusing? I don't speak (or write) in english very well...
mario_farufyno
Senior Member
Username: mario_farufyno

Post Number: 911
Registered: 9-2008
Posted on Saturday, March 30, 2013 - 1:20 pm:   Edit Post

Consider using the parallel compression trick ("NY compression"), this can brings up loudness without sacrificing original tone and envelope (wave shape). I recall GT10 can split signal and you can move your compression to a side path. That way you can be excessive on compression without changing transients (since they passes untouched through first path). This is a good trick to avoid dealing with all compression complexities and still get fine results. You combine 2 signals, one original (or processed the way you need) for tone and one heavily compressed to provide more sound pressure (to increase perceived loudness). Mix them to taste.
sonicus
Senior Member
Username: sonicus

Post Number: 2843
Registered: 5-2009
Posted on Saturday, March 30, 2013 - 1:25 pm:   Edit Post

Mike___ as per John's comment post #158 ; All of your line level outs @-10dBv or +4dBu must only go to line level in. I am assuming that you have been doing that anyway.
mario_farufyno
Senior Member
Username: mario_farufyno

Post Number: 913
Registered: 9-2008
Posted on Saturday, March 30, 2013 - 1:44 pm:   Edit Post

If lows are the bones (the structure of a tone), low-mids are the flesh and give Bass its body. Many bassists, specially in metal, take off all mids to open space to vocals and guitars. This can be effective in bigger sound systems, but smaller cabinets simply can't reproduce frequencies below 65Hz. So, you suck all life out of the Bass if you doesn't let any mids to go through. They can help one to feel the missing frequencies, making the Bass being heard more easily.

I solved this issues with a good and loud Bass Amp. Now Bass tone always feels right to me and any issue regarding people hearing me is sound tech issue or the house (if they doesn't are equiped to sell music to public). Now we have transformless class D amps and neodimiun speakers that let a bassist have a powerfull, but tiny and light gear at our disposal. Not as pleasant as gigantic tube amp classic stacks but very effective.
mike1762
Senior Member
Username: mike1762

Post Number: 989
Registered: 1-2008
Posted on Monday, April 01, 2013 - 1:22 pm:   Edit Post

I went ahead and set-up my ProSonus 16.4.2 so that I can easily switch between live and studio use... so the Behringer board is now out of the equation. Changing to my ProSonus seems to have taken care of my problem. The "compressors" in the GT10B are really not good, so I ordered a MXR M87... I think that will tame my input signal. I have PLENTY of power-amp and my cabinet is an El-Whappo Jr (a GREAT cabinet).
mike1762
Senior Member
Username: mike1762

Post Number: 990
Registered: 1-2008
Posted on Thursday, April 04, 2013 - 1:35 pm:   Edit Post

A quick report on the MXR M87: it's a pretty nifty unit if you're looking for a compressor in a stomp box format. It's WAAAYYYY more transparent than the compressors in the GT10B and does a nice job of controlling the transients.
mike1762
Senior Member
Username: mike1762

Post Number: 991
Registered: 1-2008
Posted on Friday, June 07, 2013 - 11:27 am:   Edit Post

So I've been using my ProSonus 16.4.2 with no issues regarding headroom. HOWEVER, I'm getting feedback at WAYYYY lower SPLs than I was with the Behringer board. The set-up is otherwise identical. Any explination????
mario_farufyno
Senior Member
Username: mario_farufyno

Post Number: 978
Registered: 9-2008
Posted on Friday, June 07, 2013 - 5:29 pm:   Edit Post

Monitor level too loud?
mike1762
Senior Member
Username: mike1762

Post Number: 992
Registered: 1-2008
Posted on Saturday, June 08, 2013 - 10:25 am:   Edit Post

No... I noticed this before I ever turned the monitors on.
mike1762
Senior Member
Username: mike1762

Post Number: 993
Registered: 1-2008
Posted on Saturday, June 08, 2013 - 10:28 am:   Edit Post

It was also obvious using our usual rehearsal set-up.
sonicus
Senior Member
Username: sonicus

Post Number: 2927
Registered: 5-2009
Posted on Saturday, June 08, 2013 - 11:03 am:   Edit Post

Check the gain operating level standard for -10dBV or +4dBU . A simple mechanical switch or pad or software adjustment. Perhaps this will help you . Some where in the signal chain this might need adjustment.

Sonic Regards,
Wolf

http://theartofsound.net/forum/showthread.php?234-What-does-4dBu-output-level-mean-in-terms-of-voltage

http://www.gearslutz.com/board/so-much-gear-so-little-time/569548-all-about-proper-recording-levels-saturation-distortion.html
mario_farufyno
Senior Member
Username: mario_farufyno

Post Number: 981
Registered: 9-2008
Posted on Sunday, June 09, 2013 - 6:33 am:   Edit Post

If it is feedback, it needs monitoring on (to feed the signal back to PUs). But if it is just distortion/clipping, I'd bet on too hot operational level, like Wolf suggests.
mike1762
Senior Member
Username: mike1762

Post Number: 996
Registered: 1-2008
Posted on Monday, June 10, 2013 - 12:56 pm:   Edit Post

Interestingly, there is no switch to change the operating level on either board. I use the balanced outputs (on both boards) to go to a Behringer DEQ2496 (I use it for the RTA function)and from there to my powered speakers. The entire signal path is balanced and I don't use any other outboard gear. I may have found the problem: I did not have my vocal processor (TC Electronic VoiceLive 2) properly trimmed... I think the feedback was coming from that 1 mic. I ran both boards side by side and I am once again too lound with either one... my wife is thrilled. I tried to read the references re operating level, but I am illiterate when it come to stuff like that. Is there an "Electromagnetism For Dummies" site somewhere?

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