So school me on pa systems

IanSavage

Oh, and as regards sizes - I too would be tempted to steer away from trying to do everything with 15" + horn speakers, whether active or passive; as @koneguitarist says, if you end up having to expand you'll get a far better overall sound with less money lost starting off with 10" or 12"ers for vocals-only (personally I'd lean towards the latter though, especially if you're wanting to play full-range 'interval music' and/or acoustic guitar through them) and adding a subwoofer as and when.

 

PolarityMan

Any thoughts on how to economically add a sub (can we make do with one or do you really need 2)? We currently only have vocals through the PA but we could do with bass drum too i think, only thing is coz our drummer is stupidly loud our current speakers dont have the headroom so we def need to expand before we start mic'ing more.

PolarityMan

By economically i pretty much mean the cheapest , most ghetto shit available is fine

IanSavage

In small-to-medium venues you'll often find that one subwoofer is actually better-sounding than a spaced pair of them, as with low frequencies you can get reinforcement and cancellation between a spaced pair making it harder to get a balanced sound across a whole room.

If you're going for cheap and simple I'd run one active sub off a spare aux send of the desk. Ideally to do it properly you want to run into an active crossover and then split the signal between the tops and the sub, but if you're only really wanting a bit more wallop from the kick drum you can 'fudge it' like that.

PolarityMan

Not sure if that active approach will work, its not just thump we'll want from the kick it's prob a bit of attack as well, it tends to be the double bass parts that get a tad lost when we're using our own PA.

What kind of freqs do subs go up to at the top end?

Danny1969

Only around 80 maybe 120 then the roll off is pretty steep The click and attack of a bass drum is around 1 to 3k ish so your right just a sub isn't ideal

koneguitarist

lustycourtier said:

koneguitarist said:

 

Work with drummers natural volume, don't mic him up in a small room if he is loud enough already, or you will soon run out of headroom,

  Id disagree with that. Drums need to be balanced for dynamics. Even if we are playing a tiny pub, the snare, Bassdrum and and Overhead is used. Id never take a band seriously who didnt mic the kit or Backline to some extent. The PA is there to help spread the sound.

So if your drummer is loud enough, you would still mic him up to be louder ?

 And you won't take a band seriously that doesn't mic drummer? 

Well obviously you won't take my band seriously then, I agree drums need to be balanced, 

WITH THE BAND! 

If a drummer cannot balance his kit, without Mic's, get another drummer. 

PA is to reinforce the sound you have, not create one that you don't.

koneguitarist

Danny1969 said:

Only around 80 maybe 120 then the roll off is pretty steep The click and attack of a bass drum is around 1 to 3k ish so your right just a sub isn't ideal

I would say a sub on its own is often ideal when it's needed. A lot of bands do that type of system, coupLe of active tops, and an active sub, ideal for pretty much any pub or WMC type gigs. 

We have one we can borrow any time we need it, last 5 years we have used subs, maybe 3 times, unless a large PA is supplied by venue or outdoors festival, where bigger PA's are needed.

I know some of you earn a living doing PA, and want to push for maximum equipment pretty much every gig, but let's be honest it just ain't needed in majority of cases. 

Danny1969

koneguitarist said:

Danny1969 said:

Only around 80 maybe 120 then the roll off is pretty steep The click and attack of a bass drum is around 1 to 3k ish so your right just a sub isn't ideal

I would say a sub on its own is often ideal when it's needed. A lot of bands do that type of system, coupLe of active tops, and an active sub, ideal for pretty much any pub or WMC type gigs. 

We have one we can borrow any time we need it, last 5 years we have used subs, maybe 3 times, unless a large PA is supplied by venue or outdoors festival, where bigger PA's are needed.

I know some of you earn a living doing PA, and want to push for maximum equipment pretty much every gig, but let's be honest it just ain't needed in majority of cases. 

You misunderstand he wants to use an active sub to amplify the kick drum, but if he sends the kick drum from an aux send off the desk to a typical active sub all that will amplified is the portion of the kick drum below 100hz or so .......... which in double kick rock \ metal is useless as you need a lot of definition in the kicks due to the speed and complexity of the playing 

To amplify the kick drum properly you need it in the bass bins and tops as it spreads from around 40hz to as high as 4khz

You might be thinking I'm advocating 2 subs (bass bins) instead of one maybe. Which I would anyway but that's another subject

Rocker

It might make sense for the OP and his band to hire a PA system for a gig or two. Maybe different sized rigs for different venues. Then he would be better equipped to source a rig for his band. Just a thought...

Danny1969

That is a good idea Rocker but it can get expensive. My company does PA hire but even a little dry hire of 2 active speakers and a small desk is £65 so 10 gigs down the line someone hiring could have brought something outright

I remember when I first started out though we did hire the PA until we had saved enough gig money to buy a Marshall PA head and a pair of EV speakers. We got about £55 to £60 for each gig and the PA hire was £35 so it took a while

koneguitarist

Danny1969 said:

koneguitarist said:

Danny1969 said:

Only around 80 maybe 120 then the roll off is pretty steep The click and attack of a bass drum is around 1 to 3k ish so your right just a sub isn't ideal

I would say a sub on its own is often ideal when it's needed. A lot of bands do that type of system, coupLe of active tops, and an active sub, ideal for pretty much any pub or WMC type gigs. 

We have one we can borrow any time we need it, last 5 years we have used subs, maybe 3 times, unless a large PA is supplied by venue or outdoors festival, where bigger PA's are needed.

I know some of you earn a living doing PA, and want to push for maximum equipment pretty much every gig, but let's be honest it just ain't needed in majority of cases. 

You misunderstand he wants to use an active sub to amplify the kick drum, but if he sends the kick drum from an aux send off the desk to a typical active sub all that will amplified is the portion of the kick drum below 100hz or so .......... which in double kick rock \ metal is useless as you need a lot of definition in the kicks due to the speed and complexity of the playing 

To amplify the kick drum properly you need it in the bass bins and tops as it spreads from around 40hz to as high as 4khz

You might be thinking I'm advocating 2 subs (bass bins) instead of one maybe. Which I would anyway but that's another subject

I would have thought with an active bass sub, you would come out of main out into sub, then from sub to tops, using internal crossover which is normally set around 120hz. I was thinking more about using 1 not two subs, which is more than adequate in most small venues.

mike257

@koneguitarist There's pros and cons to using aux fed subs but the big benefit is you can control exactly which channels are and aren't sent to the sub. That means you're not pushing (for example) all the low end crap that comes down your vocal mics in the stage spill into the sub which makes for a cleaner overall mix and more efficient use of the amplifier as it's not working hard to produce low frequency information that you don't want anyway. This is less of an issue in larger systems as higher end mixing desks will have filters that allow you to cut unnecessary low end from each individual channel as it hits the desk but in a small rig with a basic mixer you don't have that level of control.

koneguitarist

Sorry, even in most basic systems with subs, you will have a passive crossover, let alone an active one. A lot will depend on the sound you want, but to me I would not put anything in sub that I would not in the tops, via a crossover. The sound of an acoustic guitar being played by a solo artist would benefit from going through sub then into tops, not one or the other. Not quite sure what benefits you can hear, unless I am miss reading your post. Sorry if I am.

ICBM

I think he means that if you have an active sub as well as full-range cabs, it's better to run the sub from an aux send because you can then choose what goes into it and at what level relative to the mains. If you rely on the crossover in the sub you don't have control over that. Usually you will only want the kick drum and possibly the bass in the sub.

close2u - in all honesty, I would try to keep it as simple as possible at the moment. You don't sound like any of you know how to set up or run a complex PA yet, and buying a bunch of expensive gear (especially second hand, unless you know for certain it's all working right) and trying to work out how it all goes together in a gig - or even a practice - situation isn't going to be easy or give good results.

Start with the minimum you can - a full-range* PA intended mainly for vocals and a tiny bit of other reinforcement, with a powered sub or two and monitors, will be fine for small pub gigs. Anything bigger than that, find a soundman who knows what he's doing to both advise you on what you need - if he doesn't come with his own gear - and run it for you. There's really no point in owning a big PA unless you're going to be playing big gigs regularly, and at that point a proper soundman/roadie is worth paying out of the band takings.

*Like koneguitarist I prefer 1x12"+horn mains with subs if necessary, not 1x15"+horn which I think are a poor compromise usually. The only real reason for getting two subs not one is that they often come as the bottom part of a 'stand' with the main cab on a simple pole… and to have a spare.

mike257

koneguitarist;496432" said:

Sorry, even in most basic systems with subs, you will have a passive crossover, let alone an active one.

A lot will depend on the sound you want, but to me I would not put anything in sub that I would not in the tops, via a crossover.

The sound of an acoustic guitar being played by a solo artist would benefit from going through sub then into tops, not one or the other.

Not quite sure what benefits you can hear, unless I am miss reading your post. Sorry if I am.

Yes, think you've misunderstood me slightly. You still mix everything in to your tops as normal on the channel faders. Then connect your sub to an aux send and send only the channels with useful low frequency content (kick, bass, playback, possibly keys if appropriate) to the sub. They're all still present as normal in the tops but you have a much clearer and better controlled low end and more amplifier headroom for your sub as it's not wasting energy reproducing anything unnecessary. It's still worthwhile to apply a crossover/high pass filter to your tops as again it prevents the amplifier wasting energy and headroom reproducing frequencies that are outside the useful response of the speaker cabinet.

Danny1969

Yeah no subs at all will probably be ok in small venues. If you want to fill the Firehouse with some full on chest smacking double bass drum you might need a bit more though. We use 4 HK subs, 2 per side. Sometimes you only need a little, sometimes you need a lot

koneguitarist said:

Sorry, even in most basic systems with subs, you will have a passive crossover, let alone an active one. A lot will depend on the sound you want, but to me I would not put anything in sub that I would not in the tops, via a crossover. The sound of an acoustic guitar being played by a solo artist would benefit from going through sub then into tops, not one or the other. Not quite sure what benefits you can hear, unless I am miss reading your post. Sorry if I am.

An acoustic guitar has very little going on under 100hz so your probably not going to hear it come from a sub whever you feed it into one or not, it's not that kind of instrument

Most live engineers high pass guitars, vocals, hats, toms, virtually everything except bass guitar, kick drum and floor tom so again none of that will hit the subs.

Using subgroups (or post fade aux send )  is a useful way of gaining more control with what the subs are doing. If you send the kick, floor tom, bass guitar and maybe the keys to sub group one for example you can control how much low end comes from the subs independently of the subs own crossover and volume control by using the sub group one fader on the desk. You can also independently EQ the sub to compensate for room nodes without effecting the EQ to the tops. 

koneguitarist

Depending on sound you are after, in a solo act with just an acoustic, there is a lot going on below 150-120 where the sub will start banging it out.

In my band I use the 100 cut on desk for all vocals and acoustic, as I like the acoustic clarity to cut through, but on occasional duo work with just acoustic and mandolin etc, I leave it out, as some of the thump helps fill out sound. 

I do think all this talk about subs and crossovers maybe better in another topic though, as it's probably not helping OP in his learning about a basic PA which is probably what he needs. 

Danny1969

Yeah your right it's all gone a bit OT

close2u

Thanks all.

Confuzzled!

Anyway, here's the latest ...

http://www.thefretboard.co.uk/discussion/32659/quick-help-needed-please