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PostPosted: Fri Sep 08, 2017 12:25 pm 
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TSG wrote:
Looking at the SPL/Performance charts comparing the DR280's and the OT15's - they look fairly similar (or are there other charts?).

Are the DR280's really that much better in such a small space? What are the driving forces behind everyone choosing the 280's?

I have not heard either, so I am more asking for my own edification.

Is there anyone here that has heard both and can accurately compare the two?

I don't represent the masses, but you can take it from someone who has lived with Klipsch LaScalas and worked with horns for over 20 years.

280 over the 250 only for improved directivity and efficiency in the mids. Splitting hairs arguably, but since you asked. SPL wise, even the OT (12 or 15) would have the appplication covered. Yes, the DR are that much better, more so than is revealed in a single plot.

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PostPosted: Fri Sep 08, 2017 3:02 pm 
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TSG wrote:
What are the driving forces behind everyone choosing the 280's?


You asked for the " the highest quality SPL for the lowest amount of amperage consumed" with no limitations on size/money/etc. 280's are it. They have the highest sensitivity even if its only slightly higher than the other designs.

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PostPosted: Fri Sep 08, 2017 5:26 pm 
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Gotcha so far

a few more questions though, I'm still trying to get my bearings as which plan to buy and obviously I havent seen either plan yet

The OT15's are built with a single driver and can either be built with a single tweeter, 10 tweeter, or 20 tweeter array.

The DR280 is built with two drivers (with similar selection of drivers to the OT15's) and a 22 tweeter array.

wouldn't the OT15's use less watts purely based on the fact that it is using less of the same drivers/tweeters?

as a side question - what are the ohms of the final product of each speaker? or do you get to choose when you're wiring it?

@Bruce Weldy - I see that you have built the T39's and the OT12's, please tell me about them - what do you run them with? what do you use them for? how do you like them? and are people close to the speakers or about 30 feet away?


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PostPosted: Fri Sep 08, 2017 5:53 pm 
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TSG wrote:
wouldn't the OT15's use less watts purely based on the fact that it is using less of the same drivers/tweeters?


For the same SPL it's the other way around, remember sensitivity goes up with the more drivers/cabs you use.

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Built:
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2 x DR250 2510/asd1001
For best results, point the loud end of the array towards the audience


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PostPosted: Fri Sep 08, 2017 8:41 pm 
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TSG wrote:
The OT15's are built with a single driver...
The DR280 is built with two drivers
Both use a single woofer, and nearly identical tweeter options.


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PostPosted: Fri Sep 08, 2017 9:23 pm 
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If it really comes down to SPL requirements, go to the SPL charts.

viewforum.php?f=12

All of these charts are made with the same input so that levels the playing field for comparisons.

Instead of apples and oranges, the charts exemplify apples and BIGGER apples.

I personally run OT12s and T48s and can run 105 dBC (@ 80 feet, full bandwidth) for as long as I want on four of each.

On one 15 Amp breaker.

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PostPosted: Sat Sep 09, 2017 11:37 am 
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[deleted, some how double posted]


Last edited by TSG on Sat Sep 09, 2017 12:00 pm, edited 1 time in total.

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PostPosted: Sat Sep 09, 2017 11:59 am 
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David Raehn wrote:
All of these charts are made with the same input so that levels the playing field for comparisons. [...]
I personally run OT12s and T48s and can run 105 dBC (@ 80 feet, full bandwidth) for as long as I want on four of each .


I forgot that everything is based off of 1 watt - and how do you like your OT12/T48 combination? how does it sound? what amp(s) are you running it with? and would you do anything differently?

Bill Fitzmaurice wrote:
Both use a single woofer, and nearly identical tweeter options.


Thats good to know, thank you.

As a side question, with four t48's, can I go to 35hz or is 40hz recommended? and whats the impedance of the finished OT's and DR's?


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PostPosted: Sat Sep 09, 2017 3:33 pm 
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TSG wrote:
As a side question, with four t48's, can I go to 35hz or is 40hz recommended? and whats the impedance of the finished OT's and DR's?


Yes, 4 x T48's can be high passed at 35Hz. T48's impedance will be 2 ohms greater than the nominal impedance of the driver used, due to the horn itself, it's called acoustic impedance.
It's best though to consider the sub cabs to have the impedance of the driver, and simply know you have added a small margin of safety.

Your tops/mains impedance you can consider to be the same as the nominal impedance of the driver.

I've been pondering this for a while, and, I'm not sure it's of benefit, but part of your goal is "lowest possible amperage".

As you add more cabs to a given amp channel, overall impedance lowers (if wired in parallel).
The result of that is that output from the amp in amperes rises, and places more demand on the power supply of the amp, therefore, more power draw from your supply.
It would remain to be seen if only having 1 cab per channel, in other words, 2 amps for mains and two amps for subs, may lead to overall lower ampere demand than paralleling cabs on one amp. I guess it's worth considering.

One thing is certain though. If you series wire the cabs instead on each channel you raise, in the case of the tops/mains, the impedance to 16 ohms, which will be a significant reduction in ampere output.
Having said that, you now need an amp which can provide double the voltage swing. That would be around 90V for series wired DR280's, and 120V for series wired T48's. The Berry 6000 will just about do the 90V, but you would need another amp to provide 120V...

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PostPosted: Sat Sep 09, 2017 8:25 pm 
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Grant Bunter wrote:

I've been pondering this for a while, and, I'm not sure it's of benefit, but part of your goal is "lowest possible amperage".

As you add more cabs to a given amp channel, overall impedance lowers (if wired in parallel).
The result of that is that output from the amp in amperes rises, and places more demand on the power supply of the amp, therefore, more power draw from your supply.
It would remain to be seen if only having 1 cab per channel, in other words, 2 amps for mains and two amps for subs, may lead to overall lower ampere demand than paralleling cabs on one amp. I guess it's worth considering.

One thing is certain though. If you series wire the cabs instead on each channel you raise, in the case of the tops/mains, the impedance to 16 ohms, which will be a significant reduction in ampere output.
Having said that, you now need an amp which can provide double the voltage swing. That would be around 90V for series wired DR280's, and 120V for series wired T48's. The Berry 6000 will just about do the 90V, but you would need another amp to provide 120V...


Whether it is V * I at the 8 Ohm speaker or 2V * 1/2I at the 16 Ohm speaker, that's the same power. Divide that by the efficiency of the amplifier, and you have the AC power. You might get a little more efficiency from the amplifier at higher V/lower I as the loss in the cables and output transistors is proportional to current squared. Maybe a few percent. (Often seen in amplifier specs as lower rated power at lower output impedance) That has to be balanced with the zero-output power consumption of the amps (fans, processing, etc.) if more individual amplifiers are used.

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PostPosted: Sun Sep 10, 2017 1:28 pm 
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TSG wrote:

@Bruce Weldy - I see that you have built the T39's and the OT12's, please tell me about them - what do you run them with? what do you use them for? how do you like them? and are people close to the speakers or about 30 feet away?


My whole rig is run through dbx driveracks and Crown XLS amps. The amps are light and draw very little power. I run my whole rig of 10 speakers out front off a single 15amp circuit...(actually, the monitors, board and my fan are on the same circuit also). That rig does crowds of 500 outside. I only do live music. If you are looking to go lower for certain genres, then the T48 would be the way to go.

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