EXTRA POWER More Speakers?

[Gibbs]

I run a 6-piece covers band using as the main PA 2x RCF ART722A over 2x RCF ART 905AS. The speakers are ideal for most gigs - lightweight, reliable and sound great. At larger events, however, e.g. marquee with 500+, more volume is required.

Are there any disadvantages to simply adding more of the same speakers?

Would it be better to upgrade the system for example to the TT system. I want to stay with RCF and I want 12" speakers for best vocal performance. I note however that the TT22A only adds 1db to output, which seems of no benefit.

[Kevin Ross]

Unless you are trying to get more coverage generally adding more boxes won’t help with that type of box. Of course this being the great free country it is there are options!

 

 

 

You could go down the “Dave Rat” duel PA route and have two stacks setup each side, one for vocals only and one of everything else (or mix it around depending on what you band line up is).

 

 

 

If you are just going to go for more of the same boxes and not go for a duel PA setup then your best bet would be to stack the cabs on top of each other with the top cab inverted so the two sets of horns are a close as possible.

 

 

 

It depends of how often you do these bigger shows, would it work out cheaper keeping your existing PA and then hiring in something big for the larger shows?

[Gibbs]

Thanks for the reply.

Why do I not get more volume by adding additional speakers - I have seen other threads in this forum that talk about adding more top units when necessary?

Why the suggestion of turning a second speaker upside down - I would love to know? I can brave some technical info. if required.

[Simon Lewis]

Why the suggestion of turning a second speaker upside down - I would love to know? I can brave some technical info. if required.

 

If you can get two audio sources within ~ half a wavelength distance from each other, then the sources tend to sum (at least on axis), rather than causing interference. (That's something of a simplification, but it will do for now. It's also pretty much the starting point for line array theory).

 

The trick of inverting one box and putting it on top of another may reduce interference at HF between the two sources, but when the wavelength is smaller than the distance the two sources are apart, then the advantage is lost - and interference occurs. This tends to happen at higher frequencies (becuase they have a shorter wavelength). Therefore, the trick doesn't work for all the sounds you want to reproduce.

 

The next issue is when two sources are adjacent, it tends to modify their dispersion pattern - usually more narrow and 'lobe' like. Sometimes the two boxes trick is employed to use this lobe to your advantage, othertimes, it is an inconvience that the HF coverage is restricted compared to a single box.

 

This paper should provide some good background reading for you.

 

HTH,

 

Simon

[olly DMT]

just buy more efficient speakers, if your playing to the masses look at horn loaded jobbies, theres no point lugging lots of big boxes around when you can get more and better sound from a diffrent design of box

[basslineaudio]

We used to use the same RCF rig but found the same problem at larger gigs so we sold the RCFs and got a HK Audio Actor DX still very light and easy to transport

but it really does throw a lot further and the clarity is so much better . We got ours from Audio Works down in Surrey they have all the HK stuff of demo definately worth a look.

[Simon Lewis]

Hi, Sam,

 

Welcome to the Blue Room! You seem very pleased with Audio Works UK in Croydon, mentioning them in 100% of your posts... Are you connected with them in any way?

 

Simon

[The Boogie Man]

Just buying more efficent speakers isnt realy going to help here.

As stated before, It's more about coverage. If the boxes you have now are putting out, say 120 db spl ( I dont know the excact spec for that box) just putting a box in its place that can produce 150db spl wont help.

All that will happen is when you turn it up the people in the front row will soon reach their "tolerance level" and then complain.

Any more will just hurt the people in front and be of no benefit to others further back.

 

To get the coverage you need to make sure everyone can hear you, you have to think about speaker placement.

If you can get your mid/high cabs up and pointing into the people it will help ( think of your sound as water, a low stack is like throwing a bucket of water over the first few rows, having cabs up high and pointing down is like a shower head)

You want everyone to get wet.

 

If that isnt possible (low room etc) then think about putting extra speakers further down the hall or at the sides of the people (delay stacks)

 

hth,

 

Baz

[benhyman]

http://www.astralsound.com/vertical_pattern.htm

[olly DMT]

Just buying more efficent speakers isnt realy going to help here.

As stated before, It's more about coverage. If the boxes you have now are putting out, say 120 db spl ( I dont know the excact spec for that box) just putting a box in its place that can produce 150db spl wont help.

All that will happen is when you turn it up the people in the front row will soon reach their "tolerance level" and then complain.

Any more will just hurt the people in front and be of no benefit to others further back.

 

To get the coverage you need to make sure everyone can hear you, you have to think about speaker placement.

If you can get your mid/high cabs up and pointing into the people it will help ( think of your sound as water, a low stack is like throwing a bucket of water over the first few rows, having cabs up high and pointing down is like a shower head)

You want everyone to get wet.

 

If that isnt possible (low room etc) then think about putting extra speakers further down the hall or at the sides of the people (delay stacks)

 

hth,

 

 

Baz

horn loaded jobbies will throw the sound further, why put speakers all over the place, the band arent all over the room they are at the front?

[Kevin Ross]

It all depends on the room, horn loading a speaker does not magically change the laws of physics it is still going to lose 6db every time you double the distance. Sometimes delays are the best way forward sometimes it is not it all depends on the room and what area you are trying to cover.

[Rob_Beech]

There is quite simply no such thing as throw.

[Simon Lewis]

horn loaded jobbies will throw the sound further, why put speakers all over the place, the band arent all over the room they are at the front?

 

As Rob attests, 'throw' is something of a misnomer. Directivity is perhaps a better term, but consideration of its frequency related behaviour is important.

[6th Order]

There is quite simply no such thing as throw.

 

But there is, I've read it in the sales literature...

 

 

I think we need the OP back. Is any of this helping?

[Gibbs]

Thanks to all those who have added their opinions to my original posting. YES the various responses have been most helpful - and I reckon will have been beneficial to many others following this thread. In general it seems there are two solutions:

1. Use speakers with higher SPL. This could be achieved with horn-loaded speakers or simply more powerful speakers. Either way, care needs to be taken not to blow the heads off anyone close to the band. Raising the speakers and tilting down slighlty would seem to resolve this issue.

2. Place additional speakers further down the hall, taking into account the issue of time delay.