How do I stop the PA clipping ?

[largo]

Bit of background....

My Markbass SA450 amp is DI'ed to the front of house as well as backline.
I set the amp up with enough gain to clip the amp using fingerstyle and then back that off just a bit then set my master volume accordingly, according to Markbass manual. However, when I slap/pop (sound's so 80's) my amp doesn't clip but our sound guy (also the guitarist) moans that I'm putting the desk into the red and I'm going to blow the PA speakers !!!

For the record, I'm not going to buy a compressor. No rack space and no money :0(

Anything I can do? Could he back off the line level to the desk or is he doing things correctly by taking me to just below clipping level as well?

I'm not a sound engineer but would like to stand my ground if possible.

Cheers,

[jimmyb625]

[quote name='largo' post='466679' date='Apr 19 2009, 12:41 PM']Bit of background....

My Markbass SA450 amp is DI'ed to the front of house as well as backline.
I set the amp up with enough gain to clip the amp using fingerstyle and then back that off just a bit then set my master volume accordingly, according to Markbass manual. However, when I slap/pop (sound's so 80's) my amp doesn't clip but our sound guy (also the guitarist) moans that I'm putting the desk into the red and I'm going to blow the PA speakers !!!

For the record, I'm not going to buy a compressor. No rack space and no money :0(

Anything I can do? Could he back off the line level to the desk or is he doing things correctly by taking me to just below clipping level as well?

I'm not a sound engineer but would like to stand my ground if possible.

Cheers,[/quote]

A lot depends on the type of desk that you're using.

Does it have a selectable mic/line switch? Are you using the XLR input on the desk?

On some desks, if you take a DI into the XLR it automatically selects as mic level, so the DI gives it too much gain. You coud try using an attenuator, or an XLR to jack and go in on the jack input.

[molan]

If you're an 'aggressive' slaper then your volume on peak slapped or popped notes is going to be louder than regular fingerstyle playing.

A lot of people do use a compressor to tame this but the other thing to do would be to simply lower the volume on your bass a little on those songs that you slap on?

Tougher if you're continually alternating between slap & finger style playing of course.

If the Mark is definitely not clipping at all but is clipping the PA channel then he should absolutely be reducing the input on the desk. You should always set the level just below the loudest part of anything you're playing rather than at mid-level output.

If you have an active sound guy then he could just lower the levels on the desk on the slapped parts but sounds like you have a 'set it & leave it' policy without anyone actually monitoring input live.

To test if it's really clipping simply set everything up as normal & then stand in front of the desk and play at your loudest so you can watch the levels. If they are bouncing off the top of the dial then you definitely need to lower the desk input.

[jimmyb625]

[quote name='molan' post='466700' date='Apr 19 2009, 01:04 PM']If you're an 'aggressive' slaper then your volume on peak slapped or popped notes is going to be louder than regular fingerstyle playing.

A lot of people do use a compressor to tame this but the other thing to do would be to simply lower the volume on your bass a little on those songs that you slap on?

Tougher if you're continually alternating between slap & finger style playing of course.

If the Mark is definitely not clipping at all but is clipping the PA channel then he should absolutely be reducing the input on the desk. You should always set the level just below the loudest part of anything you're playing rather than at mid-level output.

If you have an active sound guy then he could just lower the levels on the desk on the slapped parts but sounds like you have a 'set it & leave it' policy without anyone actually monitoring input live.

To test if it's really clipping simply set everything up as normal & then stand in front of the desk and play at your loudest so you can watch the levels. If they are bouncing off the top of the dial then you definitely need to lower the desk input.[/quote]

Good info here.

To check the levels on the PA, set the channel faders to unity gain (odB) and then use the channel gain input (usually rotary pot) to bring the level up to just below clipping.

Quite a few desks have some headroom, so they can take a slight overdrive, but this is mainly to protect them, rather than acts as additional volume.

You could always insert a compressor across the bass channel, to control the levels...

[~tl]

If he is able to back off the gain control on the desk slightly, then that would be the best solution.

[jim_bass]

First, I would see how much gain he is using on the mic preamp on the desks channel.

If it is still too 'hot', then I would first try lowering your input gain on the amp and upping your master volume to keep the level, but send a lower signal to the desk (?)

If that doesn't work, get a seperate DI box (Behringer make one for about £20 - I know it's Behringer, but their DI's do the job nicely - we use a few of them or our guitars). It should have a 20Db cut switch on the DI, so that you can send a lower signal to the desk. Also, it will mean you have a good backup in your kit if the amp ever dies. This will mean connecting your amp to the DI box with a jack to jack using the amps line out and then use an XRL to connect the DI to the desk.

Hope this makes sense.

[molan]

Forgot to say - from a purely personal perspective - I think there's a lot of 'tosh' said about keeping your pre-gain input as high as possible & setting it just below clipping level.

In a real world gigging situation you'll have plenty of gain on most pre's at around a half way setting & can simply use the master gain for overall volume (unless you have a very low output passive bass).

[Adrenochrome]

I don't agree with a lot of the above.
I'd suggest that reducing the gain on your channel on the desk a long way is going to make you very quiet when you're not popping and slapping. I think you need something to ensure that you're sending a more even signal to the desk whether it be a cheap compressor or multi FX with compressor built in.

[OutToPlayJazz]

I've always found that using a lot of gain on the amp (whatever amp you're using) tends to make the bass sound too harsh. I generally operate the total opposite of making anything "clip." I usually use only about 25% input gain and around 50% output volume. Basically twice the volume compared to the gain. That way the sound is always sweet and tonally pleasant & I never make anyone's PA clip.

Edited April 19, 2009 by OutToPlayJazz

[AM1]

Find out if there is an attenuation control on the desk. If you can activate this, you should be able to use the gain over a larger portion of it's range, therefore less clipping, as opposed to turning the gain down.

[51m0n]

Your sound engineer doesnt know his stuff.

He should have a compressor inline on your channel

He should set your gain according to the loudest transient peak (in this case you slapping and popping)

He should compress your signal (v. fast attack though to catch the transient) to bring up the non-slapping stuff, and to control that huge transient peak so that he can:-

Bring up your level without it ever peaking or endangering his rig.



If he isnt doing this get a better sound engineer, or be too quiet,.

Last option, learn to slap quieter.....

[largo]

Thanks for all the advice guys.
Quick question, if I set my gain low then won't the sound guy just increase his line level to below clipping at the desk anyway. So no difference?
I can slap fairly quiet, but popping ain't so easy. Maybe I should be more aggresive with my fingerstyle !!!!

[Stylon Pilson]

[quote name='largo' post='467505' date='Apr 20 2009, 02:59 PM']Thanks for all the advice guys.
Quick question, if I set my gain low then won't the sound guy just increase his line level to below clipping at the desk anyway. So no difference?[/quote]

In a word, yes.

[quote]I can slap fairly quiet, but popping ain't so easy. Maybe I should be more aggresive with my fingerstyle !!!![/quote]

I think you should get something like a compressor or EQ pedal. Dial in the settings that give you a nice slap tone at a suitable volume, relative to the volume that you get when you play fingerstyle with the pedal off. Then just switch the pedal on for that one song.

S.P.

[51m0n]

[quote name='largo' post='467505' date='Apr 20 2009, 02:59 PM']Thanks for all the advice guys.
Quick question, if I set my gain low then won't the sound guy just increase his line level to below clipping at the desk anyway. So no difference?
I can slap fairly quiet, but popping ain't so easy. Maybe I should be more aggresive with my fingerstyle !!!![/quote]

Well that is the problem - he doesnt know how to set gain.

Sound engineering 101: gain stages.
Gain MUST be set such that your loudest sound doesn't clip.

If your level is then too low the rest of the time then you guys need a compressor somewhere. But if you're peaking that hard it may be a limiter that you really need, to catch the absolute leading edge of the transient.

[High score]

[quote name='largo' post='466679' date='Apr 19 2009, 12:41 PM']Bit of background....

My Markbass SA450 amp is DI'ed to the front of house as well as backline.
I set the amp up with enough gain to clip the amp using fingerstyle and then back that off just a bit then set my master volume accordingly, according to Markbass manual. However, when I slap/pop (sound's so 80's) my amp doesn't clip but our sound guy (also the guitarist) moans that I'm putting the desk into the red and I'm going to blow the PA speakers !!!

For the record, I'm not going to buy a compressor. No rack space and no money :0(

Anything I can do? Could he back off the line level to the desk or is he doing things correctly by taking me to just below clipping level as well?

I'm not a sound engineer but would like to stand my ground if possible.

Cheers,[/quote]

Hello Largo, used to live just across the water from the Kingdom Of Fife.

Anyway, I agree with most of what I have read from respondents however some points to consider from a sound man persepctive:


While the soundman can catch hot signals on the desk, his aim is to stabilise inputs / outputs and not be reactive so if you change styles during a track, he will have no chance of adjusting desk levels for you accurately in real time. Sure he probably should have a compressor input to your channel but this is input after the gain control on his desk and will only catch peak transients and not reduce any distortion. If he is forced to reduce your gain signal too much the sound will be weak and he will have difficulty placing you in the mix. In addition, he should not be setting up the desk or speakers to just below clip. This leaves no head room for peak / transient signals so you will blow the pa. I would suggest:

- When you set up your gain control to your bass amp it should ideally just flicker red at the strongest component of your bass signal to it so I would suggest setting up your bass amp to slap levels. Really high gain (ie signal strength) will only distort your output stage. In addition, you will be making the signal to the desk red hot as you have discovered.

- If this is still a problem, then buy a small floor di box linked between you and the desk - they usually have ''pads'' that will really reduce your input the desk but in a controlled way

- On the desk, adjust the gain control so the green ''bars'' are peaking at 0db for your channel

- make sure the gittard isn't adding any EQ to your channel which will increase output strength on the the desk (I strongly suspect he is). Try the bass channel completely neutral on the EQ and see what happens.

- I suspect it is not just your channel that is ''hot'' and there is a strong chance they all are so combined the desk will be lit like a Xmas tree!! set all channels as above.

- Lastly, is the PA up to combined mix?? Is it worth having someone off stage monitoring the desk? Do you practice your sets with the pa?

Standing your ground is fine but sound engineering is not easy either - especially if also a player at the same time - so I suggest trying to work with the sound man and back off your gain slightly as suggested. Interested in how you work this out. Sorry this has rambled but hope it helps.


ps: check out the Sound craft website. they do ''idiots guides to desk set up'' that are very good

[url="http://www.soundcraft.com/support/gtm_booklet.aspx"]http://www.soundcraft.com/support/gtm_booklet.aspx[/url]

[jbwaddy]

in my experience the desk going into the red isnt too much of a problem as long as it isnt continuesly in the red i.e its only there every now and then. also most power amps have an anti clipping device on them to protect the speakers in cases such as this. from what you have said i presume that the guitarist actually owns the p.a and is being very protective of it. i would also say that his guitar will do pretty much the same thing as your bass when he ups his volume for a solo. next time he takes a solo have a look at the desk!! you will be surprised.

[High score]

[quote name='jbwaddy' post='467630' date='Apr 20 2009, 04:55 PM']in my experience the desk going into the red isnt too much of a problem as long as it isnt continuesly in the red i.e its only there every now and then. also most power amps have an anti clipping device on them to protect the speakers in cases such as this. from what you have said i presume that the guitarist actually owns the p.a and is being very protective of it. i would also say that his guitar will do pretty much the same thing as your bass when he ups his volume for a solo. next time he takes a solo have a look at the desk!! you will be surprised.[/quote]


the desk really should never go into the red if set up correctly - even with a high transient signal - all it does is add signal noise and distortion and really means the sound man is not fully in control nor understands the gain structure and has little head space to make any adjiustments or for the pa to handle any transient peaks.

In addition, many pa manufacturers will promote their gear as having built in limiters but remember there will always be an electronic response time meaning transients will pass the limiter before they kick in. In reality, limiters should be used ''in case of emergency'' and not to accomodate poor set up or as a buffer. Continually battering the limiter will push the system until it either blows a speaker, amp or in best case just trips out through thermal overload.

completely agree though with the guitar running the system into clip as well. if the gittard can't control the bass, he probably hasn't got the other inputs set up properly either.

As for a sound man being precious with his gear, yep, why not? I got no change out of £12k for my smallest rig so why not take care of it? Think of it as an additional instrument and not just something to make the band louder. It takes a lot of practice and experience to get it right but is the difference between a mediocre gig and a sharp one.........

[largo]

Thanks again for all the advice (keep it coming) ....

The sound guy doesn't own the PA, we all do so he is no more precious than the rest of us should be. I think he has a fair idea of PA setup, or maybe just likes to think he does, after hearing what some of you guys have to say.

Good point about the guitar clipping the desk. I'll watch out for that, although and here's where I fall down. The soundman/guitarist likes to isolate each input by pressing a wee button (pardon my ignorance) on the channel and seeing what it's doing regards levels. It's not that easy for me to access the desk from my position on stage and I'm sure he'd wonder what I was up to just wandering across and pressing buttons on the desk.

Regards the DI, is there any boxes anyone could recommend. Preferably "passive" (no battery) or wouldn't that work?
My other option is a compressor pedal, and one that possibly acts as a DI box too. Do you get them?
Or, a combined tuner/compressor for my rack.

Cheers

[12stringbassist]

Gas the drummer.

[alexclaber]

[quote name='largo' post='466679' date='Apr 19 2009, 12:41 PM']However, when I slap/pop (sound's so 80's) my amp doesn't clip but our sound guy (also the guitarist) moans that I'm putting the desk into the red and I'm going to blow the PA speakers !!![/quote]

Putting the desk into the red will not blow your speakers, it'll just make your bass sound a bit dirtier.

I know it might seem impossible but with practice you can get fingerstyle and slap to match levels-wise. However if you like to boost your lows and highs and cut your mids then it will make this very difficult - leave the sound flatter so you have plenty of midrange and the fingerstyle will sound louder whilst the slap won't become overwhelming big deep thumps and trebly pings.

Don't spend any money yet - turn the gain down on the desk and experiment with your EQ. And practice!

Alex

[High score]

[quote name='largo' post='467868' date='Apr 20 2009, 09:31 PM']Thanks again for all the advice (keep it coming) ....

The sound guy doesn't own the PA, we all do so he is no more precious than the rest of us should be. I think he has a fair idea of PA setup, or maybe just likes to think he does, after hearing what some of you guys have to say.

Good point about the guitar clipping the desk. I'll watch out for that, although and here's where I fall down. The soundman/guitarist likes to isolate each input by pressing a wee button (pardon my ignorance) on the channel and seeing what it's doing regards levels. It's not that easy for me to access the desk from my position on stage and I'm sure he'd wonder what I was up to just wandering across and pressing buttons on the desk.

Regards the DI, is there any boxes anyone could recommend. Preferably "passive" (no battery) or wouldn't that work?
My other option is a compressor pedal, and one that possibly acts as a DI box too. Do you get them?
Or, a combined tuner/compressor for my rack.

Cheers[/quote]

Largo,

the 'wee' button on the desk is called PFL or 'pre fade listen'. It allows him to isolate each channel in turn and to set up individually on the desk without any other signal adding to it. I suspect he is doing it ok but simply taking it to clip as you have suggested and not setting it up for the highest level possible eg when you play slap bass. In addition, guitarists love processors and they are invariably at or above line level for the desk so can esaily send too hot a signal as well.

Re pushing buttons, get him to show you or read up on it yourself - see link I attached previously. It will take you to either a book you can down load or to a video that will walk you through it.

One of the respondents mentioned a behringer floor di. I have used these, they are very well made and under £20. They can run either from battery or passive from phantom power on the desk. To set this up, run your bass amp di out to the di box then use an xlr to your desk channel. The desk will have a button marked 48v or phantom power which will then power your di box for you. This will NOT affect your amp in any way however it will allow you to 'pad' or reduce your signal to the desk.

A compressor is not a bad idea to be honest but I suggest you/ gittard get a handle on the desk first cos you are clearly unhappy with your set up and that is not helpful when playing and wondering what the hell is going out front.

There is already a good article on this site about DI units and how they work

[maxrossell]

[quote name='largo' post='466679' date='Apr 19 2009, 12:41 PM']Bit of background....

My Markbass SA450 amp is DI'ed to the front of house as well as backline.
[b]I set the amp up with enough gain to clip the amp using fingerstyle[/b] and then back that off just a bit then set my master volume accordingly, according to Markbass manual. However, when I slap/pop (sound's so 80's) my amp doesn't clip but our sound guy (also the guitarist) moans that I'm putting the desk into the red and I'm going to blow the PA speakers !!!

For the record, I'm not going to buy a compressor. No rack space and no money :0(

Anything I can do? Could he back off the line level to the desk or is he doing things correctly by taking me to just below clipping level as well?

I'm not a sound engineer but would like to stand my ground if possible.

Cheers,[/quote]

To be honest, this is going to occur with any instrument where there's a constant level interspersed with high peaks. The most logical way to manage it would be for either you or the soundguy to get a compressor/limiter.

Without that, the option is to use your slapping as the reference point for the PA's input gain, or as the soundguy says you might end up blowing the speakers. Of course this will result in your fingerstyle playing being too quiet in the overall mix, unless as alex suggests you manage to adapt your technique to bring them into line with each other.