Out with old in with new

[Paul Norman]

Last summer I did 8 outdoor shows with a BFM system made up of 4 26" T48's, 4 Snail II's ( a design Bill had about 10 yrs ago) and 4 2" selenium comp drivers. The x-over points were 100hz and 1200hz. The snails work well up to 1200hz. Just another great BFM design. Well this summer we have 12 outdoor shows with crowds of 800 to 2000, SO! It's time go out with the old and in with new. I plan on retiring the Snails and building 4 more T48's and 12 OT12's. Power will come from QSX1450 bridged(1400watts) for each pair of subs, 3 QSX 2450 with a pair of OT12's on each side(750 watts). We use a PA Driverack with comp on kick, bass and some vocals and gates on drums all through a GL2800 832 Allen Heath. The amps might be a little over kill but it's what I have now. I really think this system will work good for us this summer. If anybody has any suggestions for improvment or change please chime in. Thanks

[Mark Coward]

I'd think about doing DR280's if you have the time, for that size rig.

[Tom]

Sidefills or floor wedgehorns?

AUX fed subs? 280s have been used in that config for the lower vocal extension in the tops.

You have a clean slate, so I wonder if you'll try these concepts that others have used successfully with Bill's cabs.

[Paul Norman]

We will be using aux fed sub. Side fills if the stage is more then say 40 ft wide. I thought about the DR280 but don't think I'll have time to get them done. What I've read about the OT12's I thought they would keep up if not maybe add more. Would you us a x-over point of 100hz?

[Tom]

I have not done this extensively. Mark Coward and David Perry have more experience at it, better to let experience respond.

This topic has been discussed quite a bit. Titans don't care where in the 80-100 Hz range they are crossed. In other words, rolloff the subs at 80-100 Hz, and highpass the tops above 80-100 Hz. The difference would be that subs are fed by AUX and tops are fed by MAIN.

Deciding factors on Tops and crossover point:

How low do vocal frequencies go in your experience? I have run sound for vocal-quartets that needed a good low bass in the tops.

Adding acoustic guitars, strings to that list of program material for "tops-only", how low do they need to go and still sound good?

[Paul Norman]

I would think that most vocals in classic rock and blues , which we mostly play, would not be below 100hz. Did I read somewhere that the more OT12's stacked in a vertical array the lower the response is?

[Paul Norman]

Or should I say the better the lower response IS. Been a long cold day!

[WB]

Did I read somewhere that the more OT12's stacked in a vertical array the lower the response is?

I think that's true for the DR's, not so much the the OT's, being the OT's have such a short horn.

[LelandCrooks]

Did I read somewhere that the more OT12's stacked in a vertical array the lower the response is?

I think that's true for the DR's, not so much the the OT's, being the OT's have such a short horn.

True.

[jbell]

as you stack, you get line array propagation (-3db) in the nearfield depending on height of stack, and frequency, but I've never heard of that 'lowering' the overall response of the speaker. (at least for a 'typical' non horn speaker)

You say 12 OT12's, are you hanging, or stacking, straight or j-array?

If stacking 6 ot212's and a couple single ot12's would be an easier stack, and still give you flexibility on how many cabinets you need (1-7 per side)

Only concern is if you need bottom cabinet to down angle 10degrees. Would be tempted to 10degree taper the top of your single ot12's at the 8" from front to rear of cab, to keep your gap at the front small ONLY if you are hanging.

Only other thought, you may want to build a small melded array only box that you could angle down into the near crowd so your OT12's don't overshoot your front row audience.

[LelandCrooks]

With DR's it does. Just like with the subs.

[Paul Norman]

I plan on stacking the OT12's . 6 on each side with the bottom one in the stack with a cross firing array. Most staging we're on is 3 or 4 feet high. Maybe a OT212 cross fired on each side for side fill would be helpful. Thanks for everyones input.

[jbell]

Here's a useful chart, to figure your near/far field of your 6stack of OT12.

[brodave2]

seems I've heard that there is no off axis advantage of the crossfiring array vs. the melded array. I have a pair of both, but have not compared them as far as off axis response.

[Bill Fitzmaurice]

seems I've heard that there is no off axis advantage of the crossfiring array vs. the melded array. I have a pair of both, but have not compared them as far as off axis response.

The response of the melded array goes both higher and lower than the standard cross-fire array both on and off-axis The cross-fire array will be dropped from the plans in favor of the melded array with the next plans revisions.