New BF system

[gdougherty]

Let's face it, 99% of the German V2 Rockets ( made by slave labour ) blew up within 15 minutes after they were launched.

Yeah, but that could just as easily have been by "design" rather than quality of labor. Recall Schindler's List and his insistence that no shell actually fire.

[Sydney]

From
http://en.wikipedia.org/wiki/V-2_rocket
"5200 produced - at least 3,172 fired"
"Antwerp (1610) & London (1358) got targeted most. An estimated 2,754 civilians were killed in London by V-2 attacks"
"Accuracy increased greatly over the course of the war, particularly on batteries where Leitstrahl-Guide Beam apparatus was installed, with V-2s sometimes landing within meters of the target."

My Mum said the scariest thing was they came in so fast ( at up to four times the speed of sound ) there was no time to react to take shelter.

[jeffbabcock]

Nice looking rig, certainly should have plenty of output. My own OTops are nearly done and they are very loud with little power. I would second the suggestions of having more boxes w/melded arrays as part of that rig.

I hate those "stagemobile" portable stages. While they are handy, the shell over the back and top does nothing to help the onstage sound. They are much better if they can be draped.

Someone mentioned about wanting to hear a rig of that size. A few comments I will offer about running rigs that large or larger - (last big show was 20 boxes of EAW KF730 w/8 SB1000's and another 10 LA400's plus 8 boxes of EAW NT56 for front and sidefills.)

When you get into large rigs DSP becomes more and more important. In particular with a large number of boxes the LF really starts coupling and can sometimes become overwhelming. So you have to change your tuning depending on the number of boxes you use. Additonally shading can be useful. You probably don't want to blast the people 10 feet away from the cabs with the same amount of HF you need to have it reach the back sections of seating. So it is common to shade the lower boxes with a bit less HF as well as less overall volume than the top (long throw) boxes. Needless to say that once rigs start getting large the more important it becomes to spend time tuning it. Smaart or similar can really prove useful here as basic RTA features are usually not all that helpful for dealing with line arrays. It becomes an issue of walking the room/area, taking multiple measurements, and treating the common trends rather than trying to be too specific with adjustments to EQ etc.

I should have my own OT12's finished soon and will be sure to post a detailed review and some measurements etc.

Cheers
Jeff

[Paul Norman]

I would second the suggestions of having more boxes w/melded arrays as part of that rig.

All my OT12's have melded arrays in them. 10 with 6 and 2 with 12. I think the ones with 6 sound a little better then the ones with 12. Bill's charts show a flatter response with 6 melded then with 12. The 12 have a better horizonal pattern.

[gdougherty]

I would second the suggestions of having more boxes w/melded arrays as part of that rig.

All my OT12's have melded arrays in them. 10 with 6 and 2 with 12. I think the ones with 6 sound a little better then the ones with 12. Bill's charts show a flatter response with 6 melded then with 12. The 12 have a better horizonal pattern.

That's the opposite of what I'd expect. The closer tweeter spacing with 12 should allow for better integration of the highs along with tighter vertical pattern control. Otherwise I'd expect the horizontal coverage to be identical as well as the sound, excepting any phase issues caused by wider element spacing. Without eq, I suppose the 6 element might sound better, less bright, but with EQ I'd expect the tweeter array to work better due to it's higher sensitivity. Are you running separate EQ's for the two different array types?

[Bill Fitzmaurice]

I suppose the 6 element might sound better, less bright, but with EQ I'd expect the tweeter array to work better due to it's higher sensitivity. Are you running separate EQ's for the two different array types?

I assume he means 6 element flat arrays and 12 element melded.

[gdougherty]

I suppose the 6 element might sound better, less bright, but with EQ I'd expect the tweeter array to work better due to it's higher sensitivity. Are you running separate EQ's for the two different array types?

I assume he means 6 element flat arrays and 12 element melded.

Good point, I'd been assuming when he said melded he meant the crossfiring melded not just an array of tweeters "melded" together instead of uncut and screwed into the tweeter mounts.

[Paul Norman]

[/quote]I assume he means 6 element flat arrays and 12 element melded.[/quote]
Good point, I'd been assuming when he said melded he meant the crossfiring melded not just an array of tweeters "melded" together instead of uncut and screwed into the tweeter mounts.[/quote]

I guess I wasn't real clear on the piezos in the boxes. The 10 have, as it states in the plans "The finished product is a six element single mouth tweeter horn array". The other 2 boxes have the 12 1016 piezos in a melded array as shown in the plans. The piezos are cut to a 45 degree angle 3-3/8 " from the end and glued together . I quess what I'm trying to say is I just followed the plans.

[gdougherty]

I guess I wasn't real clear on the piezos in the boxes. The 10 have, as it states in the plans "The finished product is a six element single mouth tweeter horn array". The other 2 boxes have the 12 1016 piezos in a melded array as shown in the plans. The piezos are cut to a 45 degree angle 3-3/8 " from the end and glued together . I quess what I'm trying to say is I just followed the plans.

For future reference the three constructed tweeter array types are usually refered to as straight array, crossfired (2 straight arrays at a 90 degree angle being phased out in favor of the melded), and the melded array (the more complicated build you describe). I'm still interested in how you'd describe the straight arrays as better. A melded pair has higher sensitivity both on and off-axis, slightly lower extension and while it has more peaks and valleys in response those can be EQ'd out. I haven't compared side-by side but I do prefer the melded to the straight arrays.

[Bill Fitzmaurice]

A melded pair has higher sensitivity both on and off-axis, slightly lower extension and while it has more peaks and valleys in response those can be EQ'd out. I haven't compared side-by side but I do prefer the melded to the straight arrays.

On-axis the melded array is only 3dB higher, and that along with the rougher response make it's benefits not obvious. It's only when you get well off-axis that its superiority becomes clear.

[screamersusa]

Very sweet. Nice system.