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[Bill Garvin]

Hi all!  I have a gig to do tomorrow where I am contemplating how to set up.  I have a 4 way quad amped system, and each frequency range has it's own individual cabinet (sub cab, low cab, mid cab, high cab), so I can stack it in different configurations.  I have 4 of each cab.  The mid and high cabs are 60 X 40 horns.  The gig is outside on a field 400 feet long and 125 ft wide.  I'm thinking of stacking the low, mid and high cabinets horizontally in order to get a bit more of a long throw and had a couple of questions.

If I stack 2 of the 60 X 40 mid and high cabs vertically on each side of the stage, will I get a bit more than the 60 degree horizontal dispersion for each side, or would I need more than 2 cabs each of mids and highs per side to get any significant amount of increase in horizontal dispersion?  Any rule of thumb when you are stacking cabs vertically how much wider dispersion you will get as you add another cab?

I'm thinking of stacking the 2 mid cabs horizontally, with the 2 high cabs stacked horizontally on top of the mids.  Would it make any sense to do a mid, high, mid, high stack instead of a mid, mid, high, high stack for the sake of making it a bit easier to align the mid and highs time wise?

If I go with a mid, mid, high, high horizontal stack, would it make any sense when I align the mids and highs in time to have both mids and both highs connected, or do 1 mid with 1 high?  I generally do just 1 speaker for each range when I'm using Smaart, but wondering since I'm trying to get the 2 mids to act as 1 unit, and the 2 highs to act as 1 unit, would it be better to have both mid & high drivers connected when I'm looking at the alignment in the time domain?

Thanks!

[Kevin McDonough]

hey

If I stack 2 of the 60 X 40 mid and high cabs vertically on each side of the stage, will I get a bit more than the 60 degree horizontal dispersion for each side, or would I need more than 2 cabs each of mids and highs per side to get any significant amount of increase in horizontal dispersion?  Any rule of thumb when you are stacking cabs vertically how much wider dispersion you will get as you add another cab?

Yes you'll get a bit more. The 60x40 degree dispersion is "nominal", i.e. average. Its where the sound is judged to have dropped off by a certain amount, usually -6db or -10db depending on what the manufacturer had measured. Its also a bit of an average as the lower frequencies of the compression driver may be a little wider, but the highest frequencies may beam a little more and be a little narrower. 

In any case, the dispersion doesn't magically stop at 60 degrees it'll still gradually drop off, but how quickly will vary. Some cabinets (usually big, fully horn loaded cabinets) will be very controlled and drop off quite quickly after the quoted dispersion, where as cabinets with a reflex mid section and a smaller compression driver horn less so.

So its really a case of knowing your cabinets and making a judgement call. may just come down to arriving a half an hour earlier than planned and having a listen. Try both ways and have a walk of the field and a listen, see how they sound.

I'm thinking of stacking the 2 mid cabs horizontally, with the 2 high cabs stacked horizontally on top of the mids.  Would it make any sense to do a mid, high, mid, high stack instead of a mid, mid, high, high stack for the sake of making it a bit easier to align the mid and highs time wise?

If I go with a mid, mid, high, high horizontal stack, would it make any sense when I align the mids and highs in time to have both mids and both highs connected, or do 1 mid with 1 high?  I generally do just 1 speaker for each range when I'm using Smaart, but wondering since I'm trying to get the 2 mids to act as 1 unit, and the 2 highs to act as 1 unit, would it be better to have both mid & high drivers connected when I'm looking at the alignment in the time domain?

Thanks!

Di you mean vertically here in this second part? i.e. one on top of the other?

In general usually best to keep the bands together, so both mids together and both highs together. The mid's wavelengths will still be long enough to couple if they're placed together (at least for part of its operating frequencies) so they'll sound better together, and while with the high's it wont make a huge amount of difference as their wavelengths are too short to couple, it'll still help a bit and make a subtle difference with phasing etc.

k

[Bill Garvin]

hey


Di you mean vertically here in this second part? i.e. one on top of the other?


k

Yes, my bad, I meant vertically.  Thanks for pointing that out, as well as taking the time to reply!

Any thoughts when I'm using Smaart to align the different drivers?  For example, should I hook up both mids on 1 speaker stack and look at that trace, or just hook up 1 mid and look at that trace?  Thanks!

[Ivan Beaver]

Yes, my bad, I meant vertically.  Thanks for pointing that out, as well as taking the time to reply!

Any thoughts when I'm using Smaart to align the different drivers?  For example, should I hook up both mids on 1 speaker stack and look at that trace, or just hook up 1 mid and look at that trace?  Thanks!

You will need to move your mic around to average the measurements.

I assume you already have a basic setup (crossovers eq delay etc) for your setup.

So now you really need to turn it all on (on one side)-since that is what is going to be used-to do the final tweaking.  Don't chase the little interactions-they will move as you move the mic.

Then copy the settings to the other side.  What happens in the middle-happens.  Nothing you can do about it.

[Bill Garvin]

You will need to move your mic around to average the measurements.

I assume you already have a basic setup (crossovers eq delay etc) for your setup.

So now you really need to turn it all on (on one side)-since that is what is going to be used-to do the final tweaking.  Don't chase the little interactions-they will move as you move the mic.

Then copy the settings to the other side.  What happens in the middle-happens.  Nothing you can do about it.

Thanks Ivan!

[Jay Barracato]

I think of a lower case "t" for the measuring positions. 3 to 4 places on axis with the speakers depending on the depth of the coverage followed by 3 to 4 measuring positions crossing the coverage.

[Bill Garvin]

I think of a lower case "t" for the measuring positions. 3 to 4 places on axis with the speakers depending on the depth of the coverage followed by 3 to 4 measuring positions crossing the coverage.

Thanks for the suggestion!  That's a great idea.  Never thought about crossing the coverage to see how much wider the dispersion would be when 2 drivers are stacked vertically vs 1 driver.  I'll have to try that at the next gig.

[Ivan Beaver]

Thanks for the suggestion!  That's a great idea.  Never thought about crossing the coverage to see how much wider the dispersion would be when 2 drivers are stacked vertically vs 1 driver.  I'll have to try that at the next gig.

The old 'stack and splay" method has been around at least since the 60s.

It gets the drivers physically closer together-so the combfiltering moves to a higher freq than if you put them side by side and splay.  Unless of course the horn cabinets are cut at 1/2 the coverage angle and the sides of the cabinets are practically touching the HF drivers.   

Hint-that is what to look for in a so called "arrayable" cabinet.  So that when you put the cabinets together in an "array"-the HF drivers as as close as possible to each other.  The mids and lows can be further away-since the wavelengths are longer.

It is ALL about wavelength and physical distance.

[Bill Garvin]

The old 'stack and splay" method has been around at least since the 60s.

It gets the drivers physically closer together-so the combfiltering moves to a higher freq than if you put them side by side and splay.  Unless of course the horn cabinets are cut at 1/2 the coverage angle and the sides of the cabinets are practically touching the HF drivers.   

Hint-that is what to look for in a so called "arrayable" cabinet.  So that when you put the cabinets together in an "array"-the HF drivers as as close as possible to each other.  The mids and lows can be further away-since the wavelengths are longer.

It is ALL about wavelength and physical distance.

Thanks Ivan!  Yes indeedy, I typically do the old "stack and splay" with mids and highs, as I'm usually trying to cover a wider area, but this gig was much deeper, so I took the "stack and no splay" approach.  Worked pretty well, but a few people off to the sides were beyond the -6 dB drop off zone of the horns.

[ProSoundWeb Community]