Speaker Placement

[MirageTool]

Hello All, this is my first post on the forum,

Quick bit of background info: I'm a mobile DJ, I just play at weddings birthdays etc. Also we sometimes allow acts to plug into our equipment if their own is not suitable for the venue we are in.

 

Link to photo of rig - http://s451.photobucket.com/albums/qq232/M...rent=Uttox1.jpg

 

I'm after some advise regarding my sound system which is a Logic System 1296, speaker placement etc. whilst on smaller gigs.

 

I'm working at a venue that has quite a high stage possibly 5ft, I have the option of putting the speaker stacks on the floor or up on the stage with me, I cant decide what will be best.

I will only be taking the tops and the twin 15's for the bottoms I will not be using the Sub's so the stack will stand approx 5ft.

 

Will the hollow stage cause the bass to rumble excessively if I put them on the stage ?

Will the tops be high enough to cut through the audience ?

Should I put the subs on the floor and the tops sitting on the stage ?

 

I am thankful for any thoughts

 

Regards

 

Phil

[tolley1466]

The stage will cause quite abit of vibrations. The subs should always be on the floor as bass travels in all directions and you don't want them to over power the tops. The tops should be as high as you can get them really. But if you have never had a problem when stacking with the audience etc it should be fine.

 

I expect Rob or Bobbsy will come along and say something totally opposite to me :)

[MirageTool]

Cheers for the reply, so the 15's should be on the floor, the tops are too big to mount on any kind of stand so I think I should just stack them on the 15's. Everything on the floor the stack will stand about 5ft. The rig has plenty of power to drive the sound through the dancers on the floor but im concerned that it will be far too loud at the front and not carry through to the back............

 

 

Phil

[smalljoshua]

Can you bring the Subs to Put the tops on, on the stage? Personally I always like to get the tops above the Audiences' heads.

 

Josh

[tolley1466]

Can you bring the Subs to Put the tops on, on the stage? Personally I always like to get the tops above the Audiences' heads.

 

Josh

 

Yeah if you don't the first few rows of people will absorb it all. I'd say your best bet is getting it above peoples heads.

Do your tops have holes on the bottom for speaker stands?

[MirageTool]

Well I could bring them in but to be honest the room is not big enough to need them, and I know I would stack the whole lot on the floor and plug them in if they were there ** laughs out loud **.

 

As for stand mounting the tops, I cant becuse they have no top hats in them. TBH I would not stand mount them because of the weight.

 

I have just thought I could put the tops on the stage onto a flight case that I carry my leads in which would get the driver of the tops about 6ft from the floor.

 

Cheers

 

Phil

[Sound In Gloucestershire]

id have the subs on the floor and the tops on the stage

 

you dont need to put them on flightcases, when on the stage, the tops will be over 7ft at the top. I tend to ensure the horns are above head height and the driver is at Ear height

[Killyp]

Think of your tops as like lamps - the higher up you get them, the better they'll be able to deliver a good sound to the majority of the crowd. If you keep them lower down, the sound they produce will be blasted into those nearest, and absorbed before it can get to the back of the audience.

 

Another tip is to angle your tops down a little. If they're above the audience's head-height, then it'll stop reflections hitting the ceiling (which as it happens is the primary source of reflections in most venues), and all of the audience will still be within your speakers' dispersion patterns.

[TimmyP1955]

Putting the cabinets on the 5' stage will cause a notch in the frequency response at about 57Hz (just above open A on the bass, and the main frequency of some kick drums). So you'll want the bass cabinets on the floor.

[MirageTool]

Thank you for all of the replies, very much appreciated.

 

Phil.

[Chappie]

Putting the cabinets on the 5' stage will cause a notch in the frequency response at about 57Hz. So you'll want the bass cabinets on the floor.

To be perfectly honest, I think something like this is really not the primary concern. Getting the tops into a decent position is far more important than a slight dip or bump in low-end frequency response due to the physical height of the stage. Yes, putting the subs on the floor may be the desirable solution in many applications, but it really isn't a blanket answer, as it may harm other situations, dependant on many different factors such as where on the floor they are located. It's all about compromise and knowing which compromise is best in each situation. The best way to find out is to try it.

 

I would advise using them to get the tops up high to cover as much of the room as possible and if the low-end is a problem, keep it in check with a little EQ.

[Kevin Ross]

Just thought I would chuck this little point in.

 

 

 

How are you going to delay the subs to the tops? By splitting the stack the subs are now in front of the tops in time so will require some delay to bring the system back to a theoretical straight stack.

 

 

 

A rough rule of thumb is 1ms per foot then tweak it from there.

 

 

 

Another thing might be to look at fitting top hats. We have one system that we can run either as a ground stack or with longer speaker poles between the tops and subs. What we have done is cut some short lengths of 35mm pole so when we do run the system as a ground stack it locks together. If we are only using 1 sub per side then we just replace the missing sub with a speaker pole

[MirageTool]

Kevin,

Erm to be honest I would not know how to delay the tops from the bottom Our 1296 uses a DBX Driverack to control the x-over and feedback but im unsure of how to alter anything in this or even if it has the facility to be able to set a delay. The drive rack was set by one of the sound engineers at logic in gainsborough, there are multiple settings saved in the menu one for the 18's, twin 15's and tops and then a second setting for when just the twin 15's and tops are in use. I have never had the need to adjust anything in the driverack.

 

Im think the tops would be far too heavy for a pole and top hat it takes two people to lift them, I really would not feel comfortable having them in the air like that.

 

Cheers

 

Phil

[Bobbsy]

Putting the cabinets on the 5' stage will cause a notch in the frequency response at about 57Hz (just above open A on the bass, and the main frequency of some kick drums). So you'll want the bass cabinets on the floor.

 

 

I assume you're thinking that the five foot stage is (roughtly) equal to a quarter the wavelength of a 57Hz tone (though, depending on the temperature, this is not exactly accurate).

 

However, I think I'm with Chappie on this one. The possible theoretical problems cured by moving the subs down would be outweighed by the poorer postion for the tops. As Chappie says, it's all a compromise but I think his is the better one.

 

Bob

[Kevin Ross]

I’m fairly sure that every driverack product has delays available on the outputs or at least everyone one I have used. Have a dig through the manual and have a look under delay or alignment delay. You could then copy the existing presets and add the suffix SS for split stack maybe?

 

 

 

It’s a fair point about the weight. I think the heaviest cab we have that re run in that configuration is 40kg worth of PD loaded top with a B&C horn