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SRX718s help needed

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Plamen Milev:
Hi,

I have 2xSRX718s and would like to power them in parallel mode on a bridged QSC RMX4050HD@230V.
My question is what power I should limit them to?
For limiter I use DCX2496 and measure voltage output with multimeter and pink noise.
The RMX4050 can run 4000W@4R and I was thinking to limit to 1600W@4R or 80v
Is this OK?

Thank you.

Chris Grimshaw:
Yep, it'll probably save your woofers from too-high peak levels.

However, the simple peak limiter on a DCX2496 can't monitor the long-term average power levels which can often burn out drivers. If you want to make sure the speakers never burn out, you either to lock down the peak limiter until the drivers don't even get warm (ie, you lose a lot of potential output), or use an amplifier or limiter that can monitor the average power level.

One of the reasons I went with the Powersoft T-series amps is that they can monitor the real power being dissipated in the loudspeaker.

Chris

Tracy Garner:

--- Quote from: Plamen Milev on September 19, 2021, 06:18:19 PM ---Hi,

I have 2xSRX718s and would like to power them in parallel mode on a bridged QSC RMX4050HD@230V.
My question is what power I should limit them to?
For limiter I use DCX2496 and measure voltage output with multimeter and pink noise.
The RMX4050 can run 4000W@4R and I was thinking to limit to 1600W@4R or 80v
Is this OK?

Thank you.

--- End quote ---

I run a 718 pair in stereo with an iTech8000 which is 2100wpc @8ohm. I haven't found the need to use a limiter. The same thing with the 728. There are some older threads here where you will get specific info on how to limit this combination.

Paul Johnson:
I've got 4 VRX918s which are pretty much the same cabinet and had a series of shows to do with them - running unlimited from two amps - one speaker to each output. Power wise at max, probably too much - but as the sound ops were all in the know, I figured few problems. It was a new VRX PA, so new to all of us. The shows were comedians and tribute bands - so think Queen, Michael Jackson, Abba, The Drifters, Four season. Nothing metal or mega. In fact - the contractual requirement was mainly for the Comedians, and The Drifters, not the tributes. However, most of them asked if they could use our PA rather than their own because it fit the shape and size of the auditorium - low roof, 1400 seats on a rake and wide and deep. First mistake was saying yes, but biggest mistake was NOT putting the old speaker crossover in the system. This was run from an X32 with crossover duties done in the desk - but no limiter engaged. We thought it unnecessary.

The Queen show pushed the volume - very loud at the mix position but also a long way, so it was excruciating at the front. The PA actually managed fine and was just too loud. Deaf band op? I don't know but no issues. We did have issues with one of the shows which was, frankly, a train wreck. Equipment failures meant their tracks, via Qlab were not all available in the mix - it sounded very strange and they tried to compensate with volume, but worst, mega amounts of bass. RMS the amp was capable of 1200W into one sub, and we lost one of the subs - nasty clicking type sounds on the transients, when investigated next day. A new driver has arrived so I'll fit it, and we used a spare similar sub for the following shows with no incident once we inserted a limiter into the X32. The Behringer amps with the built in zero attack limiters were powering the one pair of subs, but the other amp was a different brand without the limiters. Some of the Queen songs are VERY bass heavy and with the limiter in, plus the amp limiter - the system was safe even though mega loud. The screwed up mix from the train wreck show was just a mess up top but kick and bass guitar at the bottom and unpleasant to listen to. I now know that loud bass with the just in case limiter is safe - but with no limiter - too dangerous.

Plamen Milev:

--- Quote from: Tracy Garner on September 20, 2021, 03:21:36 PM ---I run a 718 pair in stereo with an iTech8000 which is 2100wpc @8ohm. I haven't found the need to use a limiter. The same thing with the 728. There are some older threads here where you will get specific info on how to limit this combination.

--- End quote ---
My worry is that I play pre-recorded music (djing) so in my case 4000W@4R bridged seems to me like asking for trouble.


--- Quote from: Paul Johnson on September 20, 2021, 04:26:13 PM ---I've got 4 VRX918s which are pretty much the same cabinet and had a series of shows to do with them - running unlimited from two amps - one speaker to each output. Power wise at max, probably too much - but as the sound ops were all in the know, I figured few problems. It was a new VRX PA, so new to all of us. The shows were comedians and tribute bands - so think Queen, Michael Jackson, Abba, The Drifters, Four season. Nothing metal or mega. In fact - the contractual requirement was mainly for the Comedians, and The Drifters, not the tributes. However, most of them asked if they could use our PA rather than their own because it fit the shape and size of the auditorium - low roof, 1400 seats on a rake and wide and deep. First mistake was saying yes, but biggest mistake was NOT putting the old speaker crossover in the system. This was run from an X32 with crossover duties done in the desk - but no limiter engaged. We thought it unnecessary.

The Queen show pushed the volume - very loud at the mix position but also a long way, so it was excruciating at the front. The PA actually managed fine and was just too loud. Deaf band op? I don't know but no issues. We did have issues with one of the shows which was, frankly, a train wreck. Equipment failures meant their tracks, via Qlab were not all available in the mix - it sounded very strange and they tried to compensate with volume, but worst, mega amounts of bass. RMS the amp was capable of 1200W into one sub, and we lost one of the subs - nasty clicking type sounds on the transients, when investigated next day. A new driver has arrived so I'll fit it, and we used a spare similar sub for the following shows with no incident once we inserted a limiter into the X32. The Behringer amps with the built in zero attack limiters were powering the one pair of subs, but the other amp was a different brand without the limiters. Some of the Queen songs are VERY bass heavy and with the limiter in, plus the amp limiter - the system was safe even though mega loud. The screwed up mix from the train wreck show was just a mess up top but kick and bass guitar at the bottom and unpleasant to listen to. I now know that loud bass with the just in case limiter is safe - but with no limiter - too dangerous.

--- End quote ---

That's exactly why I feel the limiter is a must and since I have DCX2496(A+B for tops and C for sub(sum of A+B)) and DEQ2496 I have no excuse not to set it. The thing is I have no experience with the speakers (SRX718s) and hence my post.
I did a gig and had limiters set up to 1600W@4 bridged but my tops couldn't keep up with the subs so I had to reduce the gain on the bass. They were 300W continious each. I now have Yamaha S115V rated at 500W continious each so time to revise my set up.
I also stack my SRX together for extra dB gain and always against a wall.

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