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match power amps to my speakers = please advise


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#1 Zenzilla

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Posted 30 December 2005 - 09:24 PM

Hail to the gang ~ my first post.

Request for suggestions to match power amps to my speakers.

Set-up is stereo out, so this is x2:

(1) Carvin Cabinet TR1503   [per side]    8 ohm / 600 watts   = top end
(1) Carvin Cabinet SW1801  [per side]   4 ohm / 800 watts   = bass    

I will be adding a Behringer ULTRADRIVE PRO DCX2496 shortly to do the crossover chores.

This is being feed by a Tascam DM-24 digital mixer.
Venue size varies from small (rehearsal) to medium (performance), no large rooms in this plan.

I am planning Bi-Amping via: (1) Crown CE-2000 for top end and (1) Crown CE-2000 for the bass.

Any advise would be appreciated.


tia,

Zenzilla


p.s. Please send more money!

#2 Zenzilla

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Posted 31 December 2005 - 07:38 PM

Can I answer my own question?

I am leaning toward (2) Crown K2's for powering this = quiet & powerful.

It should work for 75% of my needs, then augment as rooms get bigger.

Any thoughts are welcome.

Regards,

Zenzilla

p.s. Please send more money!

#3 DGlass

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Posted 03 January 2006 - 10:06 AM

600 watts what??? Continuous, Program, Peak?
800 watts what??? Continuous, Program, Peak?
Before you can look at doing the calculationsfor amplifier selecton, as describbed in other posting of this forum, you need to know what the power spec is actually telling you. smile.gif

#4 Zenzilla

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Posted 03 January 2006 - 02:01 PM

I originally posted what minimal information that was on the back of the speaker cabinets.

I can only add to this information from the pdf manuals:

MODEL TR1503 SPEAKER SYSTEM SPECS:
Frequency Response: 48 Hz to 19 kHz ±3 dB
Useable Low Frequency: 36 Hz (-10 dB)
Power Handling: 600w Continuous Program Power
Recommended Amp: 100 to 1200 watts
Sensitivity: 103 dB SPL, 1 Watt @ 1 meter
Coverage Angles: 90°Horizontal, 45°Vertical
Nominal Impedance: 8?
Crossover Type: C1503 Constant Voltage
Horn Driver Protection: Yes
Woofer Enclosure Type: Vented Box

MODEL SW1801 SUB WOOFER SPECS:
Frequency Response: 50 Hz to 450 Hz ±3 dB
Useable Low Frequency: 42 Hz (-10 dB)
Power Handling: 800 watts Continuous Power
Recommended Amp: 250 to 1000 watts
Sensitivity: 98 dB SPL, 1 watt @ 1 meter
Nominal Impedance: 4?
Crossover Type: Constant Voltage
Woofer Enclosure Type: Vented Box

There will be (1) TR1503 & (1) SW1801 per side for basic stereo Left/Right FOH and rehearsal/recording situations.

I do not know exactly where I will set the crossover frequency to at this time.

The K2's are at the edge of my budget, but still what I am aiming for: (1) K2 for top end & (1) K2 for the low end.


Any advice is welcome.

Zenzilla

p.s. Please send more money!

#5 Bud Bolf

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Posted 03 January 2006 - 06:18 PM

Zenzilla,
This is a reply to a Post further down. I modified it a bit to fit your scenario.

Let's start with the Basics.
There is a kinda rule of thumb that to properly power your Speakers
you take the RMS / Continuous rating and multiply it by 1.5 to 2x
Another way is to double the RMS /Continuous rating and then multiply that by 0.8 and 1.25 for the power needed.
There is even another that you can find on this website that states:
Crown paper
That if properly limited, you should have an amplifier that can reach to
the actual "Peak" of the Speakers.
The Crown article goes on to say:

"If you are mainly doing light dance music or voice, we recommend that the amplifier power be 1.6 times the Continuous Power (RMS) rating per channel. If you are doing heavy metal/grunge, try 2.5 times the Continuous (RMS) Power rating per channel. The amplifier power must be rated for the impedance of the loudspeaker (2, 4, 8 or 16 ohms)."

Now let's take the first formula and apply it to your Speakers.

1) The TR1503 is rated at 600 watts Continous / RMS." (wrms)
The 1.5x is 900wrms / the 2x is easy, it's double at 1200wrms.
That's why you see the 1200 watts max power Amp recommended.
So your Power Amp should fall somewhere in this range of 900 to 1200wrms
at 8 ohms (if per Channel or one amp Bridged at 8 ohms)
If you paralleled 2 speaker cabs to get to 4ohms, the power would
now be spread over the 2 speaker Cabs, and you would double the
numbers above. So you would want 1800wrms to 2400wrms.
This would be on a Bridged amp
(or per channel if you had 2 cabs per channel) at 4ohms.

2) The SW1801 Sub is rated at 800 watts Continous / RMS.
The spec should also say 1600 max recommended power,
so I don't know where they come up with 1000, must be a typo!
Anyway, taking info from above this means you need:
1.5x at 1200wrms to 2x at 1600wrms at 4ohms per channel or Bridged.
It is not a good idea to parallel two 4ohm cabs to get to 2ohms.
Even though some amps will give a 2ohm spec, it is usually shied away from
but you still have to do what you have to do.

The K2 Datasheet

The K2 is 500 wrms at 8 ohms, not enough for your TR1503 in Stereo.
The K2 at 4 ohms is 800 wrms, still not enough for your Sub, SW1801.

You have some decisions to make.

You can run your tops in Stereo, but the 900 to 1200 watts RMS per channel
at 8 ohms is a tough order!
You can check out the CE4000, or the I-Tech's, or put 1 Bridged amp per cab.
You could also run your top cabs Mono (Parallel two 8 ohm 1503 Cabs to get to 4 ohms)
and use an amp like the XS700 Bridged at 1900wrms at 4ohms.
That would be 950wrms per cab.
Respectable, even though it's closer to the 1.5x than the 2x rating.

The Subs SW1801 is not as bad because the cabs are 4 ohms.
You could use a CE4000 (great Sub Amp) it puts out 1200 wrms at 4ohms
per channel.

So, the above scenario would net you 950 watts per cab on your Tops
and 1200 watts per Sub cab.
I like to have more power on my Subs than on the Tops.

Another scenario that will keep your top cabs Stereo would be to use 2 CE4000's,
one on your top cabs, at 800wrms per channel per cab at 8ohms.
Slightly under the 1.5x rating of 900wrms but only by 100 watts.
The other CE4000 would still on your Subs Stereo / per channel.
In your situation I think that two CE4000's would be better than
two K2's, possibly less money as well!
The CE4000's are also BCA technology as the K2 but with a Power Factor Correction (PFC) Power Supply, that the K2's do not have.
Check them out.
I never hear the variable speed fans on mine.

Obviously you can use whatever amps and scenario that you want
as long as your power scheme falls somewhere within the above guidelines.
Note that these are Guidelines, but be it known, that if you run underpowered
to your speakers you may want to push the System and have some
clipping going on!
Always set your "Gain Structure" correctly!

I hope that I helped you on your Quest!
Take Care,
Bud

#6 Zenzilla

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Posted 03 January 2006 - 07:42 PM

Thanks Bud!  
  
Good explanation... I had done a lot of reading here and the math is about what I figured, but having input from some "All-Pros" really helps, and I appreciate your time.  
  
I had been pondering doing (4) Crown K2 amps. (really too much money for my budget)
  
This would put:  
(2) K2 amps bridged in the Carvin TR1503 tops = for stereo  
(2) K2 amps bridged in the Carvin SW1801 Sub = for stereo  
  
I need power and silence. Fan noise causes me to break out in a rash!  
  
~so~

Are the Crown CE4000 amps quiet in cool studio environments? (I could jump on this!)
  
Are the I-Tech amps quiet in climate controlled environments?  (again = ouch on the budget)
  
Regards,

Zenzilla

p.s. Send more Blue Bell Moolenium ice cream!

#7 Bud Bolf

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Posted 03 January 2006 - 08:10 PM

Howdy,
We sometimes use our CE4000 / PA in a rehearsal room the size
of a small bedroom, well, in fact it is a small bedroom. LOL
I never notice the fan, and I stand in front of it.
There is one fan per amp.
Check here for more info on the CE4000 -   CE 4000 Data Sheet

I would say, go by a local music store or Guitar Center, where they
always have them hooked up and take a listen.
Maybe you have more sensitive ears than mine, and if you hear it
see how far away you need to be, to not hear it!
I'm sure that most places would even take one out of a box and plug it in,
no speakers have to be hooked up to it, to turn it on.
I am very happy with mine!
The fans are very quiet though, plus they are on the back of the amp.
If the amp is in an Amp Rack it is even less to hear.

The 2 fan's on my new XS900 run continuosly and are very noticeable!
The XS's are not quiet amps.

When not gigging my PA is setup in my Living room,
makes CD's / DVD's sound great!
At a quiet segment in a movie (pre XS900) I did not hear the CE4000.

  Good Luck,
       Bud
PS. I am a gigging musician, and "Live Sound" individual
and do not work for Crown.

#8 DGlass

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Posted 04 January 2006 - 03:56 PM

Thanks Bud I couldn't have said it better myself. wink.gif

#9 chris226

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Posted 07 January 2006 - 04:26 PM

Do you have to have stereo? Separate left + right signals ?  If not, I suggest:

***Mono output to:
     Crown K1 (Bridged-Mono) for the tops: 750w each speaker

     Crown K2 (parallel inputs) for the subs:  800w each speaker

This in an inexpensive and ideal power-match for your speakers (with no fans)!

I stongly recommend against the (4) bridged K2's.  That configuration can very easily overpower/destroy your speakers.

If you must have left-right channel separation, consider:
     (2) Crown K1's (bridged-mono) for the tops:  1100w each speaker
          ***Or (2) CE 1000's (bridged mono):  900w each speaker (variable fans) and much easier on the $$$!

     (1) Crown K2 for subs:  800 each speaker

Hope this helps,

Chris
Christopher Ping
Pro Audio and Lighting Consultant
Lexington, KY

#10 Zenzilla

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Posted 07 January 2006 - 05:29 PM

Thanks Chris,

I am running a stereo set-up.

At this point in time I will probably save up for (2) I-Tech 4000 amps.

I think speaker destruction is more a factor of spikes and clipping and badly behaved sound techs rather than too much amp for the speaker.


Zenzilla

p.s. Must have more power... and Blue Bell Moo-lenium Ice Cream!