Boss ACS di/line out: Need clarification on connecting to PA system

[Navlys]

Hi,

I am new to live performance, and I'm confused about the two XLR outputs on the back panel of my Boss Acoustic Singer Live amp. I will have a guitar and a mic plugged into the front (with a little reverb on the vocals). Do I have to run two XLR cables from the back panel of the amp to the PA system, or can both the guitar and vocals run through just one? If I can use just one, does it matter if I use the right or the left XLR output? Also, what is the correct "Out Select" switch setting if one cable is used? I think it's "Mix," but I'd appreciate confirmation of that.

Thank you!!

[Hugh Robjohns]

I will have a guitar and a mic plugged into the front (with a little reverb on the vocals). Do I have to run two XLR cables from the back panel of the amp to the PA system, or can both the guitar and vocals run through just one?

You can send a mix from just one using the MIX switches adjacent to the XLRs.

From the manual:

OUT SELECT Specifies the output of the MIC/MIX jack and GUITAR/MIX jack.

MIX: The inputs from the MIC jack and the GUITAR jack pass through the effects of the respective channel, and are then mixed and output.

POST EFX: The inputs from the MIC jack and the GUITAR jack pass through the effects of the respective channel, and are then output separately from their respective MIC/MIX jack and the GUITAR/MIX jack.

DI: The inputs from the MIC jack and GUITAR jack do not pass through the effects, but are output separately from their respective MIC/MIX jack and the GUITAR/ MIX jack.

If I can use just one, does it matter if I use the right or the left XLR output?

You can use either, as long as you select it to provide the MIX output.

Also, what is the correct "Out Select" switch setting if one cable is used? I think it's "Mix," but I'd appreciate confirmation of that.

Confirmation delivered!

[Wonks]

Is it your PA, or a venue's PA, or will it be a mix at different times?

To understand where the different signal options for the two XLRs are taken from, have a look at the block diagram on the last page (11) of the manual.

https://static.roland.com/assets/media/ ... ng04_W.pdf


For the 'DI' output setting, the signal is taken after the pre-amp and input volume controls, but before any EQ or effects.

For the 'Post-FX' setting, as it says, the signal is taken after the preamp, EQ and effects , but before the mic and guitar signals get mixed together and fed into the looper section (which may be on or off).

The 'Mix' setting is taken after the looper and includes any signal from the Aux input there may be.

So you can have a single cable going to the PA from either the guitar or mic DI output with it set to 'mix'. What I don't know, as the manual annoyingly doesn't say, is what level the two XLRs output at. The mic and guitar outputs may be at mic level, though they are probably at line level. Assume line level and if the signal is very weak, then try a mic input on the mixer.

For FOH signals, if you've got someone mixing FOH for you, then it's always better to take individual mic and guitar signals as the sound guy really wants individual level control of the vocal and guitar signal, plus the ability to EQ them for the FOH system separately.

Whilst the harmony function needs to be under your control, if someone else is mixing, then it's best to keep the signals as flat EQ-wise and as free from reverb and delay as possible (unless you are occasionally using delay as a special effect and not an 'always on' effect). Again, you don't know what it sounds like out front, so the sound guy needs to make sure there's not too much reverb etc. If the room is already quite echo-y, then you don't want a lot of reverb in the mix. It's never a one-size-fits-all setting.

Of course if it's just you and a couple of PA speakers, then you could feed right and left speakers directly from the ACS outputs with both in 'Mix' mode. But you still need to go about front and see what it sounds like in the venue as it's going to sound very different to you a few feet in front of the amp.

[Navlys]

Thank you for the speedy replies! I’m glad to have confirmation that it’s possible to use just one XLR cable. The gig is an open mic — myself and another — both on acoustic guitars, both with our own amps running into the venue’s PA system. I’m told the sound guy is very good; but I’m new at this, and I want to understand my equipment better. I really appreciate all the help!

[Sam Spoons]

As Wonks says, if there is a sound guy he'll probably want separate feeds for the mics and guitars (if it was me driving the desk I certainly would) if for no other reason that if the sound balance is dodgy (can't hear the words/rhythm guitar/lead solo etc.) it's him who'll get the blame .

[Hugh Robjohns]

What I don't know, as the manual annoyingly doesn't say, is what level the two XLRs output at. The mic and guitar outputs may be at mic level, though they are probably at line level.

I wondered that too, as the figures are absent from the specs. But the sockets are clearly marked Line Out, so I reckon nominal line level is a safe bet, especially given the take-off points for the DI and FX feeds. The mix feed appears to come after the master volume control, so could be anything, but is also probably line level-ish for normal master volume settings!

Assume line level and if the signal is very weak, then try a mic input on the mixer.

Good advice!

[Hugh Robjohns]

The gig is an open mic — myself and another — both on acoustic guitars, both with our own amps running into the venue’s PA system. I’m told the sound guy is very good...

Chances are, then, that the vocal mics will go direct to the house sound desk and PA system, rather than through your own amp, and the 'sound guy' will either mic your amps, or take the direct guitar DI.

So you won't actually need the mix mode anyway.

[Navlys]

Thanks again!! I really appreciate it!

[Navlys]

What I don't know, as the manual annoyingly doesn't say, is what level the two XLRs output at. The mic and guitar outputs may be at mic level, though they are probably at line level. Assume line level and if the signal is very weak, then try a mic input on the mixer.

I did read somewhere that a Roland rep [who also didn't know and had to consult his Japanese counterparts] reported that they are indeed at line level.

[Wonks]

Do you use the harmony function on the amp? If so, the sound guy will need to take a DI from the amp. They'll probably use a DI box (line to mic level).

Otherwise they'll probably want you to use their mics without running them into the amp and probably take a DI from the guitars via DI boxes between the guitar and amp.

The guitar input has a 5 Meg input impedance, which is OK for a lot of piezo systems that run straight out without a preamp (and also fine for built-in preamps).

If you've got a guitar with a direct piezo output rather than an in-built pre-amp, then you will need to let the sound guy know as he will want to take a signal from the amp (as a standard active DI box won't give you a 5 meg or higher input impedance) and the guitar will probably sound bad running into a much lower input impedance (though my K&K pickups sound better into 10k rather than 10 Meg!). In that case, it will best to give them a feed from the guitar XLR out with the switch set to 'DI'.

[Navlys]

Do you use the harmony function on the amp? If so, the sound guy will need to take a DI from the amp. They'll probably use a DI box (line to mic level).

Otherwise they'll probably want you to use their mics without running them into the amp and probably take a DI from the guitars via DI boxes between the guitar and amp.

The guitar input has a 5 Meg input impedance, which is OK for a lot of piezo systems that run straight out without a preamp (and also fine for built-in preamps).

If you've got a guitar with a direct piezo output rather than an in-built pre-amp, then you will need to let the sound guy know as he will want to take a signal from the amp (as a standard active DI box won't give you a 5 meg or higher input impedance) and the guitar will probably sound bad running into a much lower input impedance (though my K&K pickups sound better into 10k rather than 10 Meg!). In that case, it will best to give them a feed from the guitar XLR out with the switch set to 'DI'.

I have a Martin D-35 acoustic to which I had a basic K&K pickup installed. I won't be using the harmony or the looping functions at all as I'm really not comfortable with them yet. I just like to be in control of my own reverb, but maybe that's something that's hard to judge when onstage?

[Wonks]

It all depends on the venue. If it's dead acoustically, then how you set it on the amp is probably going to be OK, but if it's pretty live, then you'll probably not need any reverb from the amp added to the guitar sound. The optimal PA setting will probably be somewhere in-between.

On stage you'll be hearing a lot more direct sound from the amp than reflected sound; whereas the audience will hear a lot more reflected sound. So the reverb level you need to make you feel comfortable playing, is probably more than the audience need.

Nice guitar. I have a K&K pickup in my Atkin OM37, and that sounds best straight into the line input on a mixing desk (10k ohms on the desk I used). My Fishman Loudbox Mini Has a 10 Meg input impedance and straight into that it sounds very bassy, so I modified a DIY clean preamp pedal kit to have a 10k input impedance and now use that before the amp.

[Sam Spoons]

I just like to be in control of my own reverb,

Again, why when you if got a guy out front being paid to make you sound good?

but maybe that's something that's hard to judge when onstage?

Yes, more than hard, it's actually pretty much impossible to judge accurately on stage.

Will there be foldback speakers? If so you'll get your vocals back through those, don't be afraid to ask what you want WRT reverb in them but bear in mind this is an open mic so you probably have 15 minutes, don't waste 10 of them asking for minute changes to the reverb or WHY and remember the audience will be listening to your performance not the PA.

[Navlys]

Again, why when you if got a guy out front being paid to make you sound good?

Because one of my very few stage experiences resulted in no reverb at all. Perhaps it was my fault for not asking for it.

Will there be foldback speakers? If so you'll get your vocals back through those, don't be afraid to ask what you want WRT reverb in them but bear in mind this is an open mic so you probably have 15 minutes, don't waste 10 of them asking for minute changes to the reverb or WHY and remember the audience will be listening to your performance not the PA.

Actually, my partner and I are the featured performers around which there will be open mic slots for other folks. My partner and I will have 30 minutes, and I plan to get there early and set up as much as I can beforehand. I have no idea if there will be monitors of any kind. I guess much of the electronics part of this experience will be learn-on-the-fly!

[Sam Spoons]

You give the impression of not having lots of experience playing live?

Most sound guys, even at the bottom end of the industry, are approachable and helpful and want you to be comfortable on stage so it may be that you got one of the few poor or disinterested ones on that 'no reverb' gig or, as you say, just a matter of inexperience leading to poor communication? Getting a good rapport with the sound guy is the recipe for a good experience IME so go and introduce yourselves when you arrive, he'll be busy so ask him if it's a convenient time to discuss your stage setup and be as accommodating as possible and I'm sure you'll have a great night.

[Navlys]

I have almost no experience playing on a stage. In fact, this will be exactly my second gig. LOL! I’ve always played solely through my amp for small gatherings (think family cookouts) but never on a stage with sound systems, etc. I’ve been trying to get up to speed quickly, but a few mentions of DIs, impedance, signal chains, etc., and this English major wants to go bury herself in a Victorian novel.

[Wonks]

We’ve all had to start somewhere.

All the best with gig no.2.

Hopefully this isn’t the sound person’s gig no.3, and they have enough experience to help with your stage set-up.

[Navlys]

Thanks so much! And thanks to everyone who responded so quickly. I have actually learned a lot today!

[Sam Spoons]

Glad we could help. Work at it and you'll soon learn the skill of dealing with sub-optimal stage sound (it comes with the territory I'm afraid) if you gig regularly without letting it affect your performance. I still play live and prefer to hear my vocals clean with no reverb or fx in my monitor, basically all I want from it is to know I'm singing in tune but I have worked with others who can't perform without a 'perfect' sound coming back to them...

A good sound engineer will get a good sound from the FoH speakers to suit the room and the audience* but, in the same way you can't hear what the audience is hearing he can't hear what you are hearing so your feedback on how the monitors sound is often all he has to work with**.

edit to add :- when it all goes right a good gig is one of the best experiences ever, stick at it and treasure the ones that go well.

* Assuming the usual mixing position in the audience not side of stage as sometimes happens.

** one of the 'others' mentioned above is a lovely guy and an excellent singer/guitarist but used to get a bit stressed befor the gig, at one gig a while ago, when asked what was wrong with the monitor mix, he said "it just sounds sh1t... *** I replied "sorry mate. I don't think this desk has a 'less sh1t' knob so you'll have to be a bit more specific"...

*** It didn't but he had his usual pre-gig 'stresshead' on, once the show started he was the consummate professional.

[Navlys]

SO!

The gig went pretty well last night. And of course, there was a third configuration the sound guy wanted that I hadn't considered. He said I could continue to run my guitar through my amp (then amp to PA), but he wanted my vocals plugged directly into the PA.

I asked very nicely for reverb.

[Wonks]

That's good news. Thanks for the feedback.

Hopefully you know a bit more about your new amp now and continue to explore its possibilities.

All the best for the next open mic gig. A lot less to worry about now.

[Navlys]

Indeed! Thanks again!

[Sam Spoons]

SO!

The gig went pretty well last night. And of course, there was a third configuration the sound guy wanted that I hadn't considered. He said I could continue to run my guitar through my amp (then amp to PA), but he wanted my vocals plugged directly into the PA.

I asked very nicely for reverb.

Yes, well done and glad you enjoyed the gig experience.

It's not unusual to use an amp for the guitar and the vocals direct into the PA and having the guitar sound coming from a separate speaker is useful. I'm guessing, as Hugh said up-thread, he either miked or used a DI output from the amp to the PA?

[Navlys]

It's not unusual to use an amp for the guitar and the vocals direct into the PA and having the guitar sound coming from a separate speaker is useful. I'm guessing, as Hugh said up-thread, he either miked or used a DI output from the amp to the PA?

Interesting to know that this isn't an unusual configuration! The sound guy used the DI/Line Out from the amp to the PA for the guitar. I had initially set the amp switch to "Mix" (since I originally thought I'd have the mic plugged into the amp as well) and didn't think that maybe I'd need to change that when the sound guy asked to plug the mic directly into his PA. All seemed to work, though, so I guess it was okay to leave it on "Mix."

[Sam Spoons]

Yes, mix would pass through everything going into the amp but since that was only your guitar that's fine. If you had had the mic in there as well then using two separate DI outputs (i.e. not mix) would be the way to go. The important thing is to keep the mic and the guitar separate until they get to the mixing desk so the sound guy can control them separately.