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Power Amp recommendations for (2) SRX725's


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#1 dbguitar60

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Posted 05 April 2006 - 10:55 PM

I am in the process of purchasing (2) JBL SRX725's and would like to know what you would recommend for power amp solution.

Thanks,
Dave

#2 vsop

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Posted 06 April 2006 - 08:35 PM

QUOTE(dbguitar60 @ Apr 5 2006, 11:55 PM)
I am in the process of purchasing (2) JBL SRX725's and would like to know what you would recommend for power amp solution.

Thanks,
Dave


What I would do is run it in a bia-amp config.

get yourself a CE1000 for the highs.
Now for the low end you have 2 choices.  If you want to get the max out of the speakers then buy 2 CE4000's and run them in bridged 4 ohm to each speakers LF inputs.  This will put you right on the money. Otherwise a single CE4000 will give you 1200watts RMS per channel.

Now if you run just a single amp you have to watch the clipping and be sure to set a subharmonic filter, because with only 1200watts you can easly try to overdrive the amp and send unaudiable distortion to the speakers.

If you go with the 2 4000's then just be sure to set your compressor/limiters and you will be ready to go, with more then enough juice to push those woofers.  

Now there are other amp options but this really is you best bang for the buck with the price of the CE's right now.  You can save a few dollars by going with an XLS amp for the highs, but I like the CE series better

#3 k4ng1

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Posted 10 April 2006 - 07:47 PM

Perfect timing for this question Dave, as I was about to post a question about the amp I use for my pair of 725's.

I currently run a single CE4000 amp (1200watts a side) for the 725's and I thought (before reading the advice here) that the sound was great. We have pounded some decent sized venues. I have overdriven the amp on more the one occasion and know that I am feeding these great speakers little power and when I need that little extra, I don't have it.

Question:

6 out of 10 shows we do require no more then the 725's. I think I am going to do what is recommended here.

Q: If I buy another CE4000 and set it up bridged 4ohm as suggested, do I still need the CE1000 for the highs or can I get away with the power coming from both amps?

Q: If I do need the CE1000, then I assume that each channel is 450watts driven into 4ohms solely for the highs.

Q: Also, from my little understanding, are you recommending bridged 4ohms mono for both cabs or are you saying use one Crown CE4000 for the mids (2 15's) and then strap the other CE4000 bridge mono and run that for the sub 15's?  I am confused.  

Sorry, one more...

I have never run a bi-amp config - can someone give me the breakdown?

Arvi



QUOTE(vsop @ Apr 6 2006, 05:35 PM)
QUOTE(dbguitar60 @ Apr 5 2006, 11:55 PM)
I am in the process of purchasing (2) JBL SRX725's and would like to know what you would recommend for power amp solution.

Thanks,
Dave


What I would do is run it in a bia-amp config.

get yourself a CE1000 for the highs.
Now for the low end you have 2 choices.  If you want to get the max out of the speakers then buy 2 CE4000's and run them in bridged 4 ohm to each speakers LF inputs.  This will put you right on the money. Otherwise a single CE4000 will give you 1200watts RMS per channel.

Now if you run just a single amp you have to watch the clipping and be sure to set a subharmonic filter, because with only 1200watts you can easly try to overdrive the amp and send unaudiable distortion to the speakers.

If you go with the 2 4000's then just be sure to set your compressor/limiters and you will be ready to go, with more then enough juice to push those woofers.  

Now there are other amp options but this really is you best bang for the buck with the price of the CE's right now.  You can save a few dollars by going with an XLS amp for the highs, but I like the CE series better


#4 vsop

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Posted 11 April 2006 - 12:25 PM

QUOTE(k4ng1 @ Apr 10 2006, 08:47 PM)
Perfect timing for this question Dave, as I was about to post a question about the amp I use for my pair of 725's.

I currently run a single CE4000 amp (1200watts a side) for the 725's and I thought (before reading the advice here) that the sound was great. We have pounded some decent sized venues. I have overdriven the amp on more the one occasion and know that I am feeding these great speakers little power and when I need that little extra, I don't have it.

Question:

6 out of 10 shows we do require no more then the 725's. I think I am going to do what is recommended here.

Q: If I buy another CE4000 and set it up bridged 4ohm as suggested, do I still need the CE1000 for the highs or can I get away with the power coming from both amps?

Q: If I do need the CE1000, then I assume that each channel is 450watts driven into 4ohms solely for the highs.

Q: Also, from my little understanding, are you recommending bridged 4ohms mono for both cabs or are you saying use one Crown CE4000 for the mids (2 15's) and then strap the other CE4000 bridge mono and run that for the sub 15's?  I am confused. 

Sorry, one more...

I have never run a bi-amp config - can someone give me the breakdown?

Arvi



QUOTE(vsop @ Apr 6 2006, 05:35 PM)
QUOTE(dbguitar60 @ Apr 5 2006, 11:55 PM)
I am in the process of purchasing (2) JBL SRX725's and would like to know what you would recommend for power amp solution.

Thanks,
Dave


What I would do is run it in a bia-amp config.

get yourself a CE1000 for the highs.
Now for the low end you have 2 choices.  If you want to get the max out of the speakers then buy 2 CE4000's and run them in bridged 4 ohm to each speakers LF inputs.  This will put you right on the money. Otherwise a single CE4000 will give you 1200watts RMS per channel.

Now if you run just a single amp you have to watch the clipping and be sure to set a subharmonic filter, because with only 1200watts you can easly try to overdrive the amp and send unaudiable distortion to the speakers.

If you go with the 2 4000's then just be sure to set your compressor/limiters and you will be ready to go, with more then enough juice to push those woofers.  

Now there are other amp options but this really is you best bang for the buck with the price of the CE's right now.  You can save a few dollars by going with an XLS amp for the highs, but I like the CE series better



These are the 2 best options..  You can run 2 CE4000's each in 4 ohm mono, one to each cab in passive mode.  This will power both the highs and the lows.  This will make your system rock.  

Now the second option is a little more expensive but will give you a little more clarity and abit more tuning ability.  By running a ce1000 in 2 channel stereo 8ohms you can power each stacks HF giving them plenty of power (the HF is rated 75w RMS, 150 Program & 300 max, so the ce1000 is perfect) you then do liek the above and run each CE4000 in bridged 4ohm and this time only power the LF on each cab.  

This will now allow you to run the highs and the lows seperatly for better control over the sound, you really would need a 2 way crossover and to really make the unit shine a DBX Rackdrive PA (which will do EQ, compressor/Limiting, Crossover, Delay, ETC) would be a perfect fit.  And the Rackdrive already has all the setting for this setup, so you would just plug in the equipment and through the prompts select the JBL's you have, then select BI Amped and choose the amps, and it will already have the required settings for you.  It even goes as far as telling you where to set the gains on the crown amps.  

And as a bonus it has a nice feedback eliminator as well..

#5 k4ng1

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Posted 11 April 2006 - 02:23 PM

Makes sense, thanks.

I think I am going to try option 1 first before trying option 2. I have a DBX PA in my amp rack that hardly gets used when we use the 725’s and it used more so for when we add the 728s subs.

From what I have read, you are recommending that in order to get the most out of the 725’s I can run each cab on one CE4000 in 4ohms mono, which if I understand right will give me a whopping 2800watts per cab. When you state 4ohms mono, I assuming bridge mono, correct?

I pulled this spec from the CE4000 manual

4ohm Bridge-Mono 2800watts

If my understanding is correct, then I cannot wait to try it this way and see what we can really get out of the 725’s with a much powerful amplifier.
Arvi


QUOTE(vsop @ Apr 11 2006, 09:25 AM)
QUOTE(k4ng1 @ Apr 10 2006, 08:47 PM)
Perfect timing for this question Dave, as I was about to post a question about the amp I use for my pair of 725's.

I currently run a single CE4000 amp (1200watts a side) for the 725's and I thought (before reading the advice here) that the sound was great. We have pounded some decent sized venues. I have overdriven the amp on more the one occasion and know that I am feeding these great speakers little power and when I need that little extra, I don't have it.

Question:

6 out of 10 shows we do require no more then the 725's. I think I am going to do what is recommended here.

Q: If I buy another CE4000 and set it up bridged 4ohm as suggested, do I still need the CE1000 for the highs or can I get away with the power coming from both amps?

Q: If I do need the CE1000, then I assume that each channel is 450watts driven into 4ohms solely for the highs.

Q: Also, from my little understanding, are you recommending bridged 4ohms mono for both cabs or are you saying use one Crown CE4000 for the mids (2 15's) and then strap the other CE4000 bridge mono and run that for the sub 15's?  I am confused. 

Sorry, one more...

I have never run a bi-amp config - can someone give me the breakdown?

Arvi



QUOTE(vsop @ Apr 6 2006, 05:35 PM)
QUOTE(dbguitar60 @ Apr 5 2006, 11:55 PM)
I am in the process of purchasing (2) JBL SRX725's and would like to know what you would recommend for power amp solution.

Thanks,
Dave


What I would do is run it in a bia-amp config.

get yourself a CE1000 for the highs.
Now for the low end you have 2 choices.  If you want to get the max out of the speakers then buy 2 CE4000's and run them in bridged 4 ohm to each speakers LF inputs.  This will put you right on the money. Otherwise a single CE4000 will give you 1200watts RMS per channel.

Now if you run just a single amp you have to watch the clipping and be sure to set a subharmonic filter, because with only 1200watts you can easly try to overdrive the amp and send unaudiable distortion to the speakers.

If you go with the 2 4000's then just be sure to set your compressor/limiters and you will be ready to go, with more then enough juice to push those woofers.  

Now there are other amp options but this really is you best bang for the buck with the price of the CE's right now.  You can save a few dollars by going with an XLS amp for the highs, but I like the CE series better



These are the 2 best options..  You can run 2 CE4000's each in 4 ohm mono, one to each cab in passive mode.  This will power both the highs and the lows.  This will make your system rock.  

Now the second option is a little more expensive but will give you a little more clarity and abit more tuning ability.  By running a ce1000 in 2 channel stereo 8ohms you can power each stacks HF giving them plenty of power (the HF is rated 75w RMS, 150 Program & 300 max, so the ce1000 is perfect) you then do liek the above and run each CE4000 in bridged 4ohm and this time only power the LF on each cab.  

This will now allow you to run the highs and the lows seperatly for better control over the sound, you really would need a 2 way crossover and to really make the unit shine a DBX Rackdrive PA (which will do EQ, compressor/Limiting, Crossover, Delay, ETC) would be a perfect fit.  And the Rackdrive already has all the setting for this setup, so you would just plug in the equipment and through the prompts select the JBL's you have, then select BI Amped and choose the amps, and it will already have the required settings for you.  It even goes as far as telling you where to set the gains on the crown amps.  

And as a bonus it has a nice feedback eliminator as well..


#6 jaguar_om2003

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Posted 11 April 2006 - 02:30 PM

while you're on this whole bi-amp thing:
what's a good power ratio for a three-way system?
what I mean is like if you have a 4000 watt amp
for the lows, how much power would you need for mids
as well as for the highs?

#7 Bud Bolf

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Posted 11 April 2006 - 07:33 PM

QUOTE(jaguar_om2003 @ Apr 11 2006, 03:30 PM)
while you're on this whole bi-amp thing:
what's a good power ratio for a three-way system?
what I mean is like if you have a 4000 watt amp
for the lows, how much power would you need for mids
as well as for the highs?


Hi,
It is totally dependant on the Speaker Cabinets Specs.
There is no ONE rule.

Good Luck,
  Bud

PS. There is also a lot of discussions on the JBL SRX speakers at PSW.
Check it out here:PSW Lab Lounge
Be aware that at the PSW you have to use your real name to participate,
no handles and it is strictly enforced, other than that it is a
great place for ALL questions regarding Pro Audio.

#8 rezsbc

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Posted 20 April 2006 - 10:31 AM

Why not use a single ITECH4000 or 6000 to drive the LF drivers with one box per channel?

#9 k4ng1

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Posted 08 May 2006 - 05:20 PM

Ok, following on the advice and recommendations in this posting, I tried to run my sound set up in bi-amp mode…

The set up:

Cabs
2 SRX725’s

Amps
CE1000 (8ohms stereo) powering the highs
CE4000 a side in bridge mono mode powering each cabs lows

In my rack, I have a panel which has 4 speakons of which two are wired in mono for both CE4000 amps on CH1 and the other two are for the highs.

I have a DBXPA in my rack which is also throw into the equation for the bi-amp set up.

Question:

Crown Amps: On the back of the CE4000 do I need to have the low pass and high pass filters switched at a certain point?

Problems:

So having wired everything up, I was good to go with tuning my DBX through the Auto Wizard and selecting what I needed (Bi-Amp) followed by the amps which are used for the highs and the lows. The CE1000 went into the DBX High L/R and for the CE4000 amps I had them going into the DBX lows L/R. I downloaded the recommended settings for the DBX based on the SRX725 Bi-amp configuration and after running the auto wizard I loaded the program. I did not do the other recommend steps for Auto EQ.

After that was all done, I then went through the Nav buttons on the DBX and punched in the recommended frequencies for high and lows from the datasheet from JBL.

The result:

Highs:
A distorted sound that was weak and flat.

Lows:
A very low rumbling sound that was also distorted…

Can anyone see where I may be going wrong with the above?

Arvi



QUOTE(vsop @ Apr 11 2006, 09:25 AM)
QUOTE(k4ng1 @ Apr 10 2006, 08:47 PM)
Perfect timing for this question Dave, as I was about to post a question about the amp I use for my pair of 725's.

I currently run a single CE4000 amp (1200watts a side) for the 725's and I thought (before reading the advice here) that the sound was great. We have pounded some decent sized venues. I have overdriven the amp on more the one occasion and know that I am feeding these great speakers little power and when I need that little extra, I don't have it.

Question:

6 out of 10 shows we do require no more then the 725's. I think I am going to do what is recommended here.

Q: If I buy another CE4000 and set it up bridged 4ohm as suggested, do I still need the CE1000 for the highs or can I get away with the power coming from both amps?

Q: If I do need the CE1000, then I assume that each channel is 450watts driven into 4ohms solely for the highs.

Q: Also, from my little understanding, are you recommending bridged 4ohms mono for both cabs or are you saying use one Crown CE4000 for the mids (2 15's) and then strap the other CE4000 bridge mono and run that for the sub 15's?  I am confused. 

Sorry, one more...

I have never run a bi-amp config - can someone give me the breakdown?

Arvi



QUOTE(vsop @ Apr 6 2006, 05:35 PM)
QUOTE(dbguitar60 @ Apr 5 2006, 11:55 PM)
I am in the process of purchasing (2) JBL SRX725's and would like to know what you would recommend for power amp solution.

Thanks,
Dave


What I would do is run it in a bia-amp config.

get yourself a CE1000 for the highs.
Now for the low end you have 2 choices.  If you want to get the max out of the speakers then buy 2 CE4000's and run them in bridged 4 ohm to each speakers LF inputs.  This will put you right on the money. Otherwise a single CE4000 will give you 1200watts RMS per channel.

Now if you run just a single amp you have to watch the clipping and be sure to set a subharmonic filter, because with only 1200watts you can easly try to overdrive the amp and send unaudiable distortion to the speakers.

If you go with the 2 4000's then just be sure to set your compressor/limiters and you will be ready to go, with more then enough juice to push those woofers.  

Now there are other amp options but this really is you best bang for the buck with the price of the CE's right now.  You can save a few dollars by going with an XLS amp for the highs, but I like the CE series better



These are the 2 best options..  You can run 2 CE4000's each in 4 ohm mono, one to each cab in passive mode.  This will power both the highs and the lows.  This will make your system rock.  

Now the second option is a little more expensive but will give you a little more clarity and abit more tuning ability.  By running a ce1000 in 2 channel stereo 8ohms you can power each stacks HF giving them plenty of power (the HF is rated 75w RMS, 150 Program & 300 max, so the ce1000 is perfect) you then do liek the above and run each CE4000 in bridged 4ohm and this time only power the LF on each cab.  

This will now allow you to run the highs and the lows seperatly for better control over the sound, you really would need a 2 way crossover and to really make the unit shine a DBX Rackdrive PA (which will do EQ, compressor/Limiting, Crossover, Delay, ETC) would be a perfect fit.  And the Rackdrive already has all the setting for this setup, so you would just plug in the equipment and through the prompts select the JBL's you have, then select BI Amped and choose the amps, and it will already have the required settings for you.  It even goes as far as telling you where to set the gains on the crown amps.  

And as a bonus it has a nice feedback eliminator as well..


#10 guyofsound

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Posted 09 May 2006 - 12:47 PM

Is this system for a DJ situation? If it is how may people are you trying to accomodate? It seems a little ridiculous to try to get everything out of 2 boxes, if you have subs you could put under them. It would make it sound 1000 times better and you wouldn't beat the crap out of your top end cabs. Running 2800 watts to your mid/high cabs is just to much. You will never get the sub frequencies out of them. If you are doing weddings then tops alone are fine,but if you are playing Hip hop or dance music you really should consider bringing in your subs. Your probably bringing in your laptop with music on it, right and trying to get away with as little stuff as you can.

You also might want to consider power comsumption, if you plug all of your amps into one circuit your limiting what your amps can do.

#11 guyofsound

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Posted 09 May 2006 - 01:07 PM

Buy more speaker if you want more output, you can only get so much out of a speaker ( K4ng1 ) adding more power isn't going to get you any better coverage when you need that extra push. More speakers will get you better coverage and you won't have to push the speakers you already have to the limit.

#12 k4ng1

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Posted 09 May 2006 - 01:52 PM

To answer your questions

1. Yes, this system is for a DJ system
2. How many people? Varies from 200 – 400.

“It seems ridiculous trying to get everything out of two boxes” Why? Have you heard the SRX725’s without subs? We do have subs but for the smaller end shows it is an overkill dropping subs underneath. We do everything in dual for in our inventory we have the SRX728s which rock. Also we do not beat the crap out of our speakers and it would be just plain and dumb to push 2800watts to the dual 15’s. Just because an amp has power does not mean that one will try and actually get that much power out of them! C’mon…a little common sense is always needed with live sound.

Here is JBL’s little marketing spiel on the SRX725’s

“For the ultimate in performance and simplicity, a pair of SRX725 speakers, and a single, high-power amplifier delivers superb high-level music and powerful bass. Or add SRX728S dual 18" subwoofers for truly impressive low-end. A pair of JBL 2265H Differential Drive® drivers handles an amazing 1200 watts of continuous power. The 2451 4" compression driver, respected worldwide as one of the finest high powered drivers made, provides smooth, clear mids and highs. Despite this performance, the SRX725 weighs only 100 lbs (45 kg).”

As a user, I can personally state that they give us some powerful bass and never cease to amaze for the smaller shows we do.

Let’s get back to basics, the SRX725’s are 1200RMS so let’s do the math on 1.5/2x amp power recommendations and we get 1800watts at 1.5x and 2400watts at 2x so when we strap the CE4000 amps we don’t crank all the way up, we feed more juice to the LF and it sounds great in passive. We found that running at 1200watts a side was doing more harm then good and the cabs needed more juice which they now get around 2k a side NOT as you said "2800watts" which I agree is just too much. At most, we go to around 2300watts but no way do we drive into clip.

No, we don’t get away with as much as we can by using a laptop. We cut and spin that way we know best through CDJs and 1210’s. Also, most of the music we spin is Bhangra and Bollywood which you may or may not have heard, but regardless it sounds awesome on the 725’s.

My posting was not a question on "are we doing the right thing by feed Xwatts to each cab", more so a question regarding the settings I experimented with for bi-amp mode and what needs to be set on the back of the CE4000 amps.

I appreciate your input nevertheless…

-Arvi



QUOTE(guyofsound @ May 9 2006, 09:47 AM)
Is this system for a DJ situation? If it is how may people are you trying to accomodate? It seems a little ridiculous to try to get everything out of 2 boxes, if you have subs you could put under them. It would make it sound 1000 times better and you wouldn't beat the crap out of your top end cabs. Running 2800 watts to your mid/high cabs is just to much. You will never get the sub frequencies out of them. If you are doing weddings then tops alone are fine,but if you are playing Hip hop or dance music you really should consider bringing in your subs. Your probably bringing in your laptop with music on it, right and trying to get away with as little stuff as you can.

You also might want to consider power comsumption, if you plug all of your amps into one circuit your limiting what your amps can do.