Crossover and limiting a Tuba 30 with Nady PTS 515s

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tactix
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Crossover and limiting a Tuba 30 with Nady PTS 515s

#1 Post by tactix » Wed Jun 06, 2018 6:18 pm

Hi,

I'm setting up a system that will consist of the following until I can get more T30s and some Otop12s built: One 24" 3012LF loaded Tuba 30 and two Nady PTS 515 full range cabs http://www.nady.com/products/speakers/p ... s/pts-515/ . The Nady's will be driven by a QSC RMX 1450, the Tuba by a Peavey ipr2 3000, and the signal processed by a driverack PA2. With hope there will be a second Tuba30 in the mix in short order.
Could I get some advice on crossover and limiter settings for this setup? For the crossover does the following make sense?:

1X Tuba30: High pass 35 Hz, low pass 100 Hz
Nady PTS 515: High pass 105 Hz

As for the limiter the plans say the Tuba 30 with a 3012LF should be limited to 50v. I plan to use a 60hz tone to set the limiter such that my multimeter won't go above 50v AC.
Now how about the Nady cabs? They are 8ohm speakers rated for 200 Watts RMS. What would be a reasonable voltage to limit these to? My guess is to lop a quarter of that wattage off limit to 150W / 35V. Does this make sense? Any help with this would be most appreciated.

Bruce Weldy
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Location: New Braunfels, TX

Re: Crossover and limiting a Tuba 30 with Nady PTS 515s

#2 Post by Bruce Weldy » Wed Jun 06, 2018 6:26 pm

You don't really need to limit those tops as they will start barking if you get too hot. If you are just worried about blowing 'em, then I'd limit 'em to about 25-30 volts. Based on their rating at 8 ohms, they should take 40, but I wouldn't go there. You aren't going to be getting stupid loud with just one T30 anyway.

6 - T39 4-25" 2-22" 3012LF
4 - OT12 2512 Melded/NSD2005
1 - T24
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

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tactix
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Re: Crossover and limiting a Tuba 30 with Nady PTS 515s

#3 Post by tactix » Wed Jun 06, 2018 6:37 pm

Bruce Weldy wrote:
Wed Jun 06, 2018 6:26 pm
You don't really need to limit those tops as they will start barking if you get too hot. If you are just worried about blowing 'em, then I'd limit 'em to about 25-30 volts. Based on their rating at 8 ohms, they should take 40, but I wouldn't go there. You aren't going to be getting stupid loud with just one T30 anyway.
Makes sense. The tweeters had been blown previously by my buddy and I don't much want to go through the process of finding and replacing those again so I'll give limiting them at 25 v a try.
Thanks for your reply Bruce.

Bruce Weldy
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Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: Crossover and limiting a Tuba 30 with Nady PTS 515s

#4 Post by Bruce Weldy » Wed Jun 06, 2018 10:32 pm

tactix wrote:
Wed Jun 06, 2018 6:37 pm

The tweeters had been blown previously by my buddy
Just be aware that on low quality speakers like those, the driver in that horn is probably really small and cheap.....so, be careful of boosting the highs much - especially at the crossover point. Of course, finding a spec sheet on those that gives you the crossover for that horn is probably gonna be difficult. But, I guess somewhere in the 2.5 to 3k range. (and that's purely a guess)

6 - T39 4-25" 2-22" 3012LF
4 - OT12 2512 Melded/NSD2005
1 - T24
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

Grant Bunter
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Re: Crossover and limiting a Tuba 30 with Nady PTS 515s

#5 Post by Grant Bunter » Thu Jun 07, 2018 3:07 am

Spec sheet:
http://www.nady.com/wp-content/uploads/ ... pts515.pdf

Serious bump in response around 125Hz, another at 1.5K and 2.5K. You might want to tame those with EQ.

There's lot of ways you could run that rig.
Play around with what you have suggested first.
Go to the SPL chart of the T30. See that rising response at 80Hz?
You might try a 12dB/octave BW filter as a LP at 80Hz to try to tame that rising response some (especially with the 125Hz bump from your tops).
Or try other things too. It's the best way to get to know the capabilities of your system :)
Built:
DR 250: x 2 (melded array) with March 2012 plans. 2 more under way with CD horn
T39's: 4 x 20" BP102 , 2 x 28" 3012lf.
WH8: x 3 with melded array.
Bunter's Audio and Lighting "like"s would be most appreciated...

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tactix
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Re: Crossover and limiting a Tuba 30 with Nady PTS 515s

#6 Post by tactix » Thu Jun 07, 2018 10:37 am

Bruce Weldy wrote:
Wed Jun 06, 2018 10:32 pm
tactix wrote:
Wed Jun 06, 2018 6:37 pm

The tweeters had been blown previously by my buddy
Just be aware that on low quality speakers like those, the driver in that horn is probably really small and cheap.....so, be careful of boosting the highs much - especially at the crossover point. Of course, finding a spec sheet on those that gives you the crossover for that horn is probably gonna be difficult. But, I guess somewhere in the 2.5 to 3k range. (and that's purely a guess)
The horn driver is a Goldwood GT-1188 Piezo but I swapped out its capacitor for a higher quality one. Same for the crossover whose point is 3.5Khz. I also installed L-Pad Attenuators between the crossover and the horn to be able to turn that thing down as it could be quite harsh. Replacing the capacitors mellowed them out considerably though - sort of negating the usefulness of attenuator in my mind but it's in there. Anyway I suspect I've modified that frequency response curve some. Is it difficult to generate an SPL chart for a given speaker without lab equipment? Say if I had an RTA mic?

I'll be careful with the highs at 3.5k.

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Re: Crossover and limiting a Tuba 30 with Nady PTS 515s

#7 Post by tactix » Thu Jun 07, 2018 10:39 am

Grant Bunter wrote:
Thu Jun 07, 2018 3:07 am
Spec sheet:
http://www.nady.com/wp-content/uploads/ ... pts515.pdf

Serious bump in response around 125Hz, another at 1.5K and 2.5K. You might want to tame those with EQ.

There's lot of ways you could run that rig.
Play around with what you have suggested first.
Go to the SPL chart of the T30. See that rising response at 80Hz?
You might try a 12dB/octave BW filter as a LP at 80Hz to try to tame that rising response some (especially with the 125Hz bump from your tops).
Or try other things too. It's the best way to get to know the capabilities of your system :)
Thanks Grant - I'll play around with it. This gives me a good place to start.
Cheers!

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