Voltage limits for 8 Titan 48's and 4 Otop 12's

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Bruce Weldy
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Re: Voltage limits for 8 Titan 48's and 4 Otop 12's

#16 Post by Bruce Weldy » Sun Apr 12, 2020 3:32 am

SethRocksYou wrote:
Sat Apr 11, 2020 8:01 pm

Here's how to calculate that out... speed of sound (1125fps) divided by frequency = wavelength in feet. Divide by 4 to get quarter wavelength or multiply by 2 to get two wavelength's.
Or, just use this handy dandy calculator......

http://www.mcsquared.com/wavelength.htm

It, along with the voltage/ohm/wattage calculator have been in my browser favorites for years.

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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Seth
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Re: Voltage limits for 8 Titan 48's and 4 Otop 12's

#17 Post by Seth » Sun Apr 12, 2020 4:57 am

Bruce Weldy wrote:
Sun Apr 12, 2020 3:32 am
SethRocksYou wrote:
Sat Apr 11, 2020 8:01 pm

Here's how to calculate that out... speed of sound (1125fps) divided by frequency = wavelength in feet. Divide by 4 to get quarter wavelength or multiply by 2 to get two wavelength's.
Or, just use this handy dandy calculator......

http://www.mcsquared.com/wavelength.htm

It, along with the voltage/ohm/wattage calculator have been in my browser favorites for years.
To each his own I guess. I always calculate that stuff. I find it quicker in most cases, it keeps the mind sharp, and I find value in understanding the relationships of the values.

Volts x volts divided by ohms = watts
The square root of the product of watts x ohms = volts

I've just committed them to memory and it's nothing to punch them into a calculator. For me, it takes less thought than googling a calculator and sifting through them to find one that I like.
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

Grant Bunter
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Re: Voltage limits for 8 Titan 48's and 4 Otop 12's

#18 Post by Grant Bunter » Sun Apr 12, 2020 5:03 am

wbredin wrote:
Sun Apr 05, 2020 1:33 pm

1. EQ the subs properly in the 360 (Did this already).
There’s been quite a bit of focus, quite rightly, on setting correct adequate slopes, proper high passes, and voltage limits, so far, but to me something is still missing.

Please tell us exactly what you mean when you say “EQ the subs properly”.
The subs should require very little EQ.
Have you also increased the sub channel output gain?
Built:
DR 250: x 2 melded array, 2x CD horn, March 2012 plans.
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...

Bruce Weldy
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Re: Voltage limits for 8 Titan 48's and 4 Otop 12's

#19 Post by Bruce Weldy » Sun Apr 12, 2020 5:06 am

SethRocksYou wrote:
Sun Apr 12, 2020 4:57 am
Bruce Weldy wrote:
Sun Apr 12, 2020 3:32 am
SethRocksYou wrote:
Sat Apr 11, 2020 8:01 pm

Here's how to calculate that out... speed of sound (1125fps) divided by frequency = wavelength in feet. Divide by 4 to get quarter wavelength or multiply by 2 to get two wavelength's.
Or, just use this handy dandy calculator......

http://www.mcsquared.com/wavelength.htm

It, along with the voltage/ohm/wattage calculator have been in my browser favorites for years.
To each his own I guess. I always calculate that stuff. I find it quicker in most cases, it keeps the mind sharp, and I find value in understanding the relationships of the values.

Volts x volts divided by ohms = watts
The square root of the product of watts x ohms = volts

I've just committed them to memory and it's nothing to punch them into a calculator. For me, it takes less thought than googling a calculator and sifting through them to find one that I like.
I hear ya.....there are some things I care about having the "why" and others I just want the tool. Those two sites are available on my browser with two clicks to get there...

And why the hell are we talking about this in the middle of the night? 5am here - been up for two hours.....I hate when that happens....

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."

wbredin
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Joined: Thu Jun 17, 2010 9:36 pm

Re: Voltage limits for 8 Titan 48's and 4 Otop 12's

#20 Post by wbredin » Sun Apr 12, 2020 5:16 pm

Hey guys, one more weird question. If i'm stuck with just my prolite 7.5 for the subs, which is 2 ohm stable, and 12 titans @ 8ohms each, is there any clever way to wire 6 per side so that the amp is seeing above 2ohms and i'm still able to push all 12?. I realize the amp will probably run out of horsepower at high levels, but it might be fine at like 80/90% given how efficient the subs are?

My best guess is three paralleled into two, 2.6 ohm strings. Then series those two strings to around 6 ohms for the six. At that resistance level, i'd only see around 2kw being fed to each stack of 6, so only 333w per titan. Which, honestly, would still move some air, but no where near the '450RMS' rated max.

Thoughts?

This is mostly a theoretical exercise...I just wanted to see what you all had to say before buying more expensive amplifiers...

Bruce Weldy
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Re: Voltage limits for 8 Titan 48's and 4 Otop 12's

#21 Post by Bruce Weldy » Mon Apr 13, 2020 8:52 am

wbredin wrote:
Sun Apr 12, 2020 5:16 pm
Hey guys, one more weird question. If i'm stuck with just my prolite 7.5 for the subs, which is 2 ohm stable, and 12 titans @ 8ohms each, is there any clever way to wire 6 per side so that the amp is seeing above 2ohms and i'm still able to push all 12?. I realize the amp will probably run out of horsepower at high levels, but it might be fine at like 80/90% given how efficient the subs are?

My best guess is three paralleled into two, 2.6 ohm strings. Then series those two strings to around 6 ohms for the six. At that resistance level, i'd only see around 2kw being fed to each stack of 6, so only 333w per titan. Which, honestly, would still move some air, but no where near the '450RMS' rated max.

Thoughts?

This is mostly a theoretical exercise...I just wanted to see what you all had to say before buying more expensive amplifiers...
The old saying, "Just because you can, doesn't mean you should" applies here. Yes, you could do some wiring gymnastics to get 'em all on one amp, but in the long run it would be a constant pain to put into action on a regular basis especially if you have to use special cabling or a breakout box and teach that to anyone who helps.

Looking at the Prolite 5 specs - it has enough power to run 4 subs on a channel....the problem is with mixing it with the 7.5. It can be done, but it will require using the limiters on the amps themselves and you have to then use the internal DSP to keep the volumes leveled out.....that would requiring doing a voltage test on each amp and a lot of manipulation of the software.

A few options would be:

1. Buy another 7.5 and put 3 subs on each channel in parallel.

2. Sell the 5.0 and buy a 7.5 - run 3 channels for 4 subs each and run the mains mono on the additional channel.

3. Sell the 7.5 and buy another 5.0 and a smaller amp for tops. The 5.0 has enough voltage swing to run the subs at full power according to the spec sheet.

Option 3 is probably the best bet money wise. Option 1 is most expensive and will give you some growth room for more cabinets and lots of headroom.

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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Seth
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Re: Voltage limits for 8 Titan 48's and 4 Otop 12's

#22 Post by Seth » Mon Apr 13, 2020 11:33 am

Just put 6 per channel and see what happens. If the amp doesn't go into a protect mode and you like what you hear, no worries. Titan's/Tuba's are a nominal 10 ohms anyway. (8 for anything loaded with a LAB)
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

NukePooch
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Re: Voltage limits for 8 Titan 48's and 4 Otop 12's

#23 Post by NukePooch » Mon Apr 13, 2020 5:36 pm

SethRocksYou wrote:
Mon Apr 13, 2020 11:33 am
Just put 6 per channel and see what happens. If the amp doesn't go into a protect mode and you like what you hear, no worries. Titan's/Tuba's are a nominal 10 ohms anyway. (8 for anything loaded with a LAB)
Just keep in mind that if the amp goes into protect, it won't be during soundcheck...
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Grey Owl
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Re: Voltage limits for 8 Titan 48's and 4 Otop 12's

#24 Post by Grey Owl » Thu Apr 16, 2020 6:00 pm

stolen your calculator. Loads of fun.............
You have two ears and one mouth. Use them in the same ratio!!

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