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Author Topic: Crest or Crown for SRX728's  (Read 19570 times)

Doug Fowler

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Re: Crest or Crown for SRX728's
« Reply #20 on: December 07, 2011, 06:54:12 PM »


Hi doug

What limiters do you use and what type of setting you apply. Ijust got my second PL4.0. I use to have only 1 pl4 for my 2 728's.  My process is either ashley analog xr crossover or DB PA.

Othane

Othane -

Easiest route is to merely use a peak limiter to keep amps' clip lights from lighting.

Note that there may some more headroom after the light comes on, maybe not. To be sure, use a 'scope on the output and set peak limiter threshold accordingly.

With 4.0s you should be good to go.  It should be difficult to damage the woofs since the 4.0 is well within 728 power limits.

After this, you can experiment with gentler limiting if you don't like the sound of the peak limiters.  Or keep it out of limit :-)

4.0 has a clip limiter but I do not know how effective it is.

Where is DDT when you need it?  ;-)

   
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Brawndo, the Thirst Mutilator. 
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Kurt Stephens

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Re: Crest or Crown for SRX728's
« Reply #21 on: December 08, 2011, 03:09:53 PM »

Update:

OK so I ended up going with a PL380 for the two SRX728's after some chat with a dealer.

Any comments on how well the PL380 will drive these two subs?
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Doug Fowler

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Re: Crest or Crown for SRX728's
« Reply #22 on: December 08, 2011, 05:15:35 PM »

Update:

OK so I ended up going with a PL380 for the two SRX728's after some chat with a dealer.

Any comments on how well the PL380 will drive these two subs?

It will kick ass.   Great choice.
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Brawndo, the Thirst Mutilator. 
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It's got what plants crave.

Kurt Stephens

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Re: Crest or Crown for SRX728's
« Reply #23 on: December 08, 2011, 05:40:44 PM »

It will kick ass.   Great choice.

That is what I like to hear - can't wait to test it out. It seems like it should be a definite upgrade from the two HPR181i's we have - or for that matter the XTi's that I was initially considering to run these. 

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Jonathan Betts

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Re: Crest or Crown for SRX728's
« Reply #24 on: December 08, 2011, 06:30:17 PM »

That is a great amp. How are you going to limit for thermal protection?
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Kurt Stephens

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Re: Crest or Crown for SRX728's
« Reply #25 on: December 08, 2011, 08:01:00 PM »

That is a great amp. How are you going to limit for thermal protection?

Processing will be done by a selection of dbx Driveracks that are already in place.
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Jonathan Betts

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Re: Crest or Crown for SRX728's
« Reply #26 on: December 08, 2011, 08:05:54 PM »

Processing will be done by a selection of dbx Driveracks that are already in place.

Do the Driverack's have RMS limiting capabilities?
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Tracy Garner

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Re: Crest or Crown for SRX728's
« Reply #27 on: December 08, 2011, 08:28:06 PM »

Situation: $2000 to power a pair of SRX728s.

Obviously I's prefer to go with something more substantial like a Macrotech - but this is all I was given to work with. I am aware two XTi4002's aren't going to drive the 728's to their full potential.

Question: Two Crest CC4000's or two Crown XTi4002's? DSP is not needed (system uses driverack PX). Weight is not a factor. Does anyone have first hand experience with the CC series?
Am I missing a better potential option?

Thanks in advance.

Quite possibly the entity you buy the USED I-Tech from may have it as factory recertified. Besides, when people say they won't buy anything used, I tell them I bet they never took a trip in a brand new airplane and I bet they never drank any new water but they trust both of those...
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Jonathan Betts

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Re: Crest or Crown for SRX728's
« Reply #28 on: December 08, 2011, 08:31:22 PM »

It seems like most people power the SRX series cabinets way over their RMS ratings. I have always set my RMS limiters below the RMS ratings of my cabinets and my peak limiters at 2x the RMS ratings of the cabinets. If I'm not using my ITechs I will use my QSC 4050 HD in stereo so thermal issues are at a minimum. Are the limiters in the driveracks and units like the (DBX1066) going to protects your speakers from thermal damage?

EDIT:

Side note:  One of my tech's roasted a 718 this past weekend because he did not check to see if the RMS limiters were engaged. This was using a ITech 6000 (1500 watts 8 ohms)When they are engaged they are set for 500 watts 8 ohms.
« Last Edit: December 08, 2011, 10:07:45 PM by Jonathan Betts »
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Othmane Alaoui

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Re: Crest or Crown for SRX728's
« Reply #29 on: December 09, 2011, 04:31:04 PM »

It seems like most people power the SRX series cabinets way over their RMS ratings. I have always set my RMS limiters below the RMS ratings of my cabinets and my peak limiters at 2x the RMS ratings of the cabinets. If I'm not using my ITechs I will use my QSC 4050 HD in stereo so thermal issues are at a minimum. Are the limiters in the driveracks and units like the (DBX1066) going to protects your speakers from thermal damage?

EDIT:

Side note:  One of my tech's roasted a 718 this past weekend because he did not check to see if the RMS limiters were engaged. This was using a ITech 6000 (1500 watts 8 ohms)When they are engaged they are set for 500 watts 8 ohms.

Hi !

We are a lot here using srx rig !  I am completely lost with this rms limiters. My 728's are fired with 2 x PL4.0. Am I in trouble pushing them ? how can we set a limit with a regular analog crossover such dbx234xl or similar process ?

If I understand correctly : Peak Watts : 6400W and average is 4000W
So ohm law states : V= R*I or P = V*V / R and heat losses are P = R * I * I
So :

4000w * 4 ohm =16000 and sqrt(16000) = 126.5V and 4000/126.5 = 31A  = To get Max output from an amp.

And at Peak power : 6400 * 4 ... = 160V and 160/4 = 40A.

For sure, there is cable and distance and also reactive contribution but let keep it negligeable.

My question here is : If from an outlet you can get at maximum 120V and 20A - How is it possible to reach Peak limitation under these specific conditions assuming that the impedance will remain around 4 ohms.

So if my understanding is okay, with this voltage and current limitation, how its possible to reach the drivers Watt limits ...

Please correct me if I am wrong !

Thank you,

Othmane







« Last Edit: December 09, 2011, 04:45:06 PM by Othmane Alaoui »
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Re: Crest or Crown for SRX728's
« Reply #29 on: December 09, 2011, 04:31:04 PM »


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