Setting Limiters

Helpful hints on how to build 'em, and where to get the stuff you need.
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Seth
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Joined: Thu Sep 10, 2009 8:06 pm
Location: Sacramento, California, USA
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Re: Setting Limiters

#46 Post by Seth »

Hello Alex,

What speaker cabinet and what driver? Link to driver specs is helpful.
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

alexk
Posts: 30
Joined: Thu Mar 24, 2016 1:11 pm
Location: Austin, TX

Re: Setting Limiters

#47 Post by alexk »

For subs, find the listed speaker with the closest xMax to yours....use that voltage.
Ah, but I wish it were that simple...

For the T48:

15NLW9300 - 8mm xmax - 80V
3015LF - 9.6mm xmax - 60V
Lab15 - 11.8mm xmax - 60V

Definitely something else at play here. =)

I'm trying to find out about the maths so that the answer would be useful to others.


My own situation is a bit more confusing - my builder (a harp luthier) has volunteered to build a pair of T48s in exchange for an amp and him using it on his stage for 8 weeks a year. He's also adamant about using a pair of drivers he has on hand (15" drivers somewhere between this and this in parameters - they came out of a pair of Alto TS115). My current plan is to swap out to drivers from the plans once his 8 weeks is up, but I'd rather not blow his drivers during the middle of the festival run.

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Bill Fitzmaurice
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Re: Setting Limiters

#48 Post by Bill Fitzmaurice »

There's no simple math for horn loaded sub limiting because there are too many variables. You must model the driver in HornResp to see how much voltage it can safely take. The 15NLW9300 listed xmax of 8mm is not a Klippel measurement, which will be closer to 10mm. As for your builder, he should stick to harps, as he doesn't know jack about speakers. Neither of the drivers you linked will work well as a subwoofer driver, in any cabinet. The Alto TS115 isn't a sub, it's a midbass speaker, so whatever driver it contained isn't going to work as a sub driver, and I'd say chances of blowing it are pretty good if he does so.

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Tom Smit
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Location: Sarnia, Ont. Canada

Re: Setting Limiters

#49 Post by Tom Smit »

Based on what Bill said, and that the continuous power limit of the TS115 is 250w, I'm going to venture and say 20 volts. Based on the spec sheet of the cab, the -3db point is 75 hz and the -10 db point is 50 hz. This definitely proves that the cab is a mains speaker and not a sub.
TomS

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

Re: Setting Limiters

#50 Post by Bruce Weldy »

Tom Smit wrote: Wed Feb 19, 2020 11:46 pm Based on what Bill said, and that the continuous power limit of the TS115 is 250w, I'm going to venture and say 20 volts. Based on the spec sheet of the cab, the -3db point is 75 hz and the -10 db point is 50 hz. This definitely proves that the cab is a mains speaker and not a sub.
And better set the high pass at about 60hz......

I believe there are fried speakers in the future.....

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
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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