More pa or better pa?

[agedhorse]

For the subs the 1602 bridged is "ok", but probably not the best way to go long term. 800 watts per box is fine, that's not the issue. That's running the amp pretty hard when hitting rated power. I would recommend a 3402 (or the new 04 series) in stereo (not bridged), somewhere around 800-1000 watts per box, be sure that somewhere there is a high pass filter preferably around 35Hz but between 30 and 40hz is ok. Start with about 90Hz, the tops 3dB lower level than the subs (that should be pretty close). Be sure the amp's limiters are engaged all around.

 

I am not a fan of running a 3002 or a 3402 brigded into those subs, IME it's too much power without the proper protective limiting (which you do not have) and the benefit that you are giving up is really only ~2dB of maximum sub SPL while greatly increasing the risk of damage to those drivers. Almost my entire inventory of subs is 718's, I have customers with these boxes as well. You do not want to pay for a recone as it's a bit pricy.

[Rbts]

. You do not want to pay for a recone as it's a bit pricy.

 

 

I have heard Agedhorse say stuff like this a lot. Usually in reference to a post about "bridging".

[gdawg55]

A pair EV ZXA5 along with a pair Yorkville LS801P would do you justice to keep up with rock bands with racks and stacks back lines. So you won't run out of gas so fast if they get excited with the stage wash volume. Plus the EV's have a HPF switch you could use for the LS subs and use the LPF knob to blend the 2 together. Just my 2 cents worth.

 

 

This is a great combo. I run this same rig and never run into issues with needing more in small to medium size venues (up to 200 or so). But if you want to stay JBL I would suggest a proper crossover or dsp (even better) and add more MRX boxes. If you have the funds, then upgrade to SRX with Itech level amps.

[Robsco]

where would you recommend setting high pass filter on mrx 515. I realize the plx1602 might be a bit too small but I already have three of these. Durability issues asside, do you think I will be giving up much sound vs. a 3402 unbridged.

[dcastar]

Apologies as I haven't read this thread in its entirety... However;

Buying a BETTER PA (rather than "more" PA) was the single best investment I made into my band.

[agedhorse]

 

where would you recommend setting high pass filter on mrx 515. I realize the plx1602 might be a bit too small but I already have three of these. Durability issues asside, do you think I will be giving up much sound vs. a 3402 unbridged.

 

 

The 515 would not use a seperate high pass filter. The crossover between the subs and tops provide this function.

 

Are you thinking about powering 2 of the 718's on a 1602 bridged or 1 amp per box? It's not the sound quality, or the size of the amp, it's that if you are bridging into 2 boxes that's asking a lot for an amp like that into 4 ohms bridged.

[Unalaska]

Not to throw a wrench into the bridged 1602 discussion, a few years ago I used a pair of cx502s bridged on dual 18s with a 3402 on top and a B word EP1500 on horns. The CX's were used for maybe 2 years in every scenario I'd use a larger amp in stereo. Not once did they thermal or act up, the only downside was the power draw of the 2 since 95% of the time they were driving 4 ohm loads each.

I moved these to HF duty in stereo and now use a PLX1804 for MF and the PLX3402 on subs. There hasn't been much of any spl reduction at all, there has been a 60lbs drop in weight and it only requires 1 circuit running fult tilt. My next move is use another plx3402 and run 1 for Left LF/MF and 1 as right LF/MF. I'd trust this scenario to drive a 2ohm load on subs easier than the current setup.

[Robsco]

I was going to try running both subs off one bridged 1602 for 800 watts each. How hard is this on the amp? I always get conflicting answers to this question, ranging from the amp is designed for it so its fine to I would never do it you will toast the amp.

[Craig Vecchione]

 

I was going to try running both subs off one bridged 1602 for 800 watts each. How hard is this on the amp? I always get conflicting answers to this question, ranging from the amp is designed for it so its fine to I would never do it you will toast the amp.

 

 

Less stress is pretty much always better than more stress.

[agedhorse]

 

I was going to try running both subs off one bridged 1602 for 800 watts each. How hard is this on the amp? I always get conflicting answers to this question, ranging from the amp is designed for it so its fine to I would never do it you will toast the amp.

 

 

Under reasonable conditions it will work fine... ie. moderate ambient temperatures, not driving into limiting, etc. If you can manage the real world conditions so that you don't have to deal with this then it's fine but often what you would LIKE to have happen isn't the same as what actually happens.

[nchangin]

I think real world results (amp not handling it for extended time) vs rated power ratings are in conflict in your quest to your answer. those speakers want 800 watts continuous, 1602 is 1600 bridged @ 4 ohms so you would be giving the speakers each 800 watts which is rated continuous.

What I have researched is certain amps last longer or better reliability for sustained current to the speakers, while QSC 1602 is a quality product there are other amplifiers designed for your applications better suited for your needs in running your application. i.e. Mr Andy (aged horse) post suggesting a larger amplifier with the limiters on to protect from over powering the speakers and the main difference: your not running in bridged mono mode. Amps last longer not running in bridged mono mode. One amplifier that is designed for extended bridge mono mode is the QSC 1850HD.

Moral of the story: if you can afford a larger amp do it, otherwise run with what you have however, expect that the amp will be running harder and hotter than a larger amp and in turn has a increased possibility of failure vs a QSC 3402 (not in bridge mode) (post # 51Andy)

Request correction from Andy if I'm off.

[lifeloverwg]

For what it's worth, I've been running a PLX 1802 in bridged mono mode sometimes into light limiting on my TH-Minis for around 5 years with no issues so far. It's never gotten particularly hot and once again this summer I had to run it and the rest of the PA and backline hard off of one 20 amp circuit. So while it may well be running harder and hotter in bridged mono than it would be in stereo, my limited experience has been that it is rated for it and capable of doing it. If I was doing sound on a fulltime basis I would probably switch to an amp running in stereo. Or not...

I don't think much changed in the design from the 1602 to the 1802 besides a slight increase in power rating. Andy can let me know if I"m wrong. Prior to getting the 1802 I was running a PLX 1202 in bridged mono mode into our previous subs and it too handled being driven into light limiting for the 3-4 years it was in that use. I also just used the 1202 in bridged mono mode on my sub at Burningman where it was driven into occasional limiting in a very hot environment for 3-4 hours daily with no problem. However, the Carvin amp I was using on the tops that was housed in the same case as the QSC 1202 did shut down once for thermal protection even though it never came close to limiting.

[walkerci]

As a point of reference...

I'm running (4) SRX-718 on a QSC PLX3602 in stereo and (4) MRX515 on a QSC PLX3102 in stereo.

Plenty of volume, clarity, and coverage for 200-250 person clubs.

[jlb]

Originally Posted by walkerci

As a point of reference...

I'm running (4) SRX-718 on a QSC PLX3602 in stereo and (4) MRX515 on a QSC PLX3102 in stereo.
Plenty of volume, clarity, and coverage for 200-250 person clubs.

Good to hear of someone treating their SRX/MRX rig properly.

[agedhorse]

Originally Posted by walkerci

As a point of reference...

I'm running (4) SRX-718 on a QSC PLX3602 in stereo and (4) MRX515 on a QSC PLX3102 in stereo.
Plenty of volume, clarity, and coverage for 200-250 person clubs.

well matched IMO.

My comments about bridged 1602's are specifcally about reduced thermal margin which may come into play under high ambient temperatures. Doesn't mean you WILL have problems, just that you should be aware of the increased possibility.

[Unalaska]

There are plenty of amps that will do around 700-800w @ 8ohms, PLX 3402, yamaha p7000s, crown xti4000 sorta. If you already own the 1602 then go for it. High ambient temp is the only thing I didn't have to deal with much, outdoors in the summer it's rarely over 90.

[nchangin]

 

Originally Posted by walkerci

As a point of reference...

I'm running (4) SRX-718 on a QSC PLX3602 in stereo and (4) MRX515 on a QSC PLX3102 in stereo.

Plenty of volume, clarity, and coverage for 200-250 person clubs.

 

May I ask how you are mounting the two 515's on the 718's? Just using poles?

[Robsco]

Got to use the new 718's saturday night at a local marina. Odd venue, kinda half inside, half out on the lake. Anyway I wasn't overly impressed with the amount of improvement over the old 518 subs. Possibly this is due to being semi outside. Do you think more power, possibly around 1200 per speaker would help or is that just too much? Next weekend I'll try using all four subs. When doing this would you recomend using one of each per side, two of same per side, or one per side with a center cluster? Forgot to mention I ran 718's off one of the plx 1602's bridged

[Mutha Goose]

 

Originally Posted by Robsco

...Anyway I wasn't overly impressed with the amount of improvement over the old 518 subs...

 

That's too bad. If only someone could have warned you about that ahead of time...

[Robsco]

 

Originally Posted by Mutha Goose

That's too bad. If only someone could have warned you about that ahead of time...

 

Do I detect sarcasm here? It seems to me the consensus of advice indicated that I could expect about a 50% improvement in bottom end

[gdawg55]

I would say you need a better amp for driving the low end. You will notice a big improvement if you get a proper amp (Itech 4k, PL380, Crest 9200, etc). PLX amps perform much better on the top end vs the low end. They will obviously work for your application, but you will notice a huge improvement if you get a better amp IMHO. Properly set up, you should be able to detect better performance from the SRX718 vs the MRX subs.

[Robsco]

I have a plx 2402 that I could use bridged. I just don't want to push too hard. Also I didn't mean to imply there was no difference. just not what I was expecting. I was feeding the 518 700watts. So wondering if the 718 just wants more than 800.

[jlb]

If you read through earlier posts you will find the answer to your question

[agedhorse]

Originally Posted by gdawg55

I would say you need a better amp for driving the low end. You will notice a big improvement if you get a proper amp (Itech 4k, PL380, Crest 9200, etc). PLX amps perform much better on the top end vs the low end. They will obviously work for your application, but you will notice a huge improvement if you get a better amp IMHO. Properly set up, you should be able to detect better performance from the SRX718 vs the MRX subs.

I call BS on the PLX/PL being poor on subs. That's a perpetuation of urban myth IMO.

I have a whole bunch of 718's powered 2 per side on PLX-3402's and they are used with mid level national acts all the time with no complaints at all. None. Zero.

I also have enough rig for the gig, it's properly set up, processed and operated. That just might have something to do with the results.

[agedhorse]

Originally Posted by Robsco

I have a plx 2402 that I could use bridged. I just don't want to push too hard. Also I didn't mean to imply there was no difference. just not what I was expecting. I was feeding the 518 700watts. So wondering if the 718 just wants more than 800.

Nope, 800 watts should get you about 3dB more output (equal to doubling the power on your 518's except they won't handle this and if you were to double the power on the 518's you might get 1dB more due to power compression). Above 800 watts, you will experience enough power compression on the 718's that for doubling of the power you only gain maybe 1.5dB in practice for a whole lot more risk.

You will also get better low frequency extension with the 718's.

Where do you have your dip switches set at? What are you using for processing? Parameteres?

My guess... it's a set-up problem first, then maybe some additional unreasonable expectations.