Am I under powering my system?

[Tomis17]

Hi guys, I havent been here for the longest time but I am happy to be back. I am running 4 srx718s powered by two xti4002 in bridge mode and 4 srx712m powered by one xti4002 in stereo mode. I feel like I am not getting enough coverage. Any thoughts? Your insights would be much appreciated. Tom

[agedhorse]

You are pretty maxed out (unless you like to pay for recones) on the subs, you could probably use a little more on the tops but you are unlikely to gain more than a dB or two in practice and increase the risk of damage beyond that.

[Tomis17]

It is funny you say that because the subs are not keeping up with tops. I am not sure if speaker placement is a factor. This last gig I set like I always do with 2 sets of speakers on either side of the stage. The tops are pole mounted over the subs. During the gig there seem to be a low volume from 0-20 feet. From 30-40 feet the volume seemed louder. I am not sure if there was cone cancellation happening. Only thing that could have cause come cancellation would that the stage was quite narrow and the speakers weren't place far enough away from the back of the room. I am estimating the stage to be about 20' from side to side and only 6 feet from front to back. Speakers were placed parallel to the stage on each side.

[Tomis17]

Btw, do you still have the settings for these speaker I can get from you? I lost them when got rid of my other lap top.

[RoadRanger]

You are pretty maxed out (unless you like to pay for recones) on the subs, you could probably use a little more on the tops but you are unlikely to gain more than a dB or two in practice and increase the risk of damage beyond that.

Am I missing something or didn't he say he was feeding each 718 2000 watts? I'd say he was way past maxed out already LOL.

[agedhorse]

Pretty maxed out

[agedhorse]

I don't have the tuning parameters handy, but off the top of my head x-over at 90Hz, 24dB LR crossover, HPF 24dB/Octave BW @30Hz, and the sub gain should be about 5-6dB greater than the tops gain give or take. This will get you plenty close. You will want to be limiting the subs at about 2dB below the rated output. Not sure how to do it on your amp model as I do everything inside stand alone DSP.

 

That should be a heck of a potent rig. I have a slew of those subs and tops.

[Craig Vecchione]

It is funny you say that because the subs are not keeping up with tops. I am not sure if speaker placement is a factor. This last gig I set like I always do with 2 sets of speakers on either side of the stage. The tops are pole mounted over the subs. During the gig there seem to be a low volume from 0-20 feet. From 30-40 feet the volume seemed louder. I am not sure if there was cone cancellation happening. Only thing that could have cause come cancellation would that the stage was quite narrow and the speakers weren't place far enough away from the back of the room. I am estimating the stage to be about 20' from side to side and only 6 feet from front to back. Speakers were placed parallel to the stage on each side.

 

What you're describing sound a lot more like room modes cancelling in the area you're getting low volume. It's definitely not a power issue.

[Tomis17]

Roadranger: I am feeding 3200 watts @ 4 ohms into two subs (8 ohms each). The subs are rated at 800/1600/3200. Agedhorse: I will create new presets with those recommended settings. Thanks! CraigV: How could I avoid the cancellation in the future?

[RoadRanger]

Roadranger: I am feeding 3200 watts @ 4 ohms into two subs (8 ohms each). The subs are rated at 800/1600/3200.

Which is it LOL? Once above the lower (RMS) value you better be budgeting for recones. In any case hereabouts in the land of "lead kick" it takes TWO 718's to keep up with a single 712 so yes, you're sub-light and need FOUR per side - assuming that's what you were really asking by "under-powered". How many people are you trying to cover? The four you have should be fine for ~500 indoors if properly processed (HPF set properly in particular)? OTOH they might already be suffering from worn-out suspensions .

[agedhorse]

I disagree with the ratio of subs to tops. For the types of music I do, 1:1 is about right.

 

Powered at between 1x and 1.5x the RMS rating of the speaker, that's about the point of diminishing returns. Power compression and reliability reduction becomes a real issue beyond this.

[hfc7713]

My SRX system is only 2 x SRX718's on XTI6002 and 2 SRX715's on XTI6002.

I have used this set up outside and been able to get fantastic sound levels from it -not huge festival size of course but parking lots and such. I usually couple the subs which makes a difference.

I am surprised you are not getting the levels you expect from yours.

 

One thing to note, I used to run the XTI4002's and switched to the XTI6002's. Much better and I like not having to bridge my amps - keeps it clean. You would get 2100 w per side on your 4 subs without bridging!. Just a thought.

 

 

[Tomis17]

The rating is 600 rms 1200 continuous and 2400 max. I am surprised that the ratio suggested is 2 subs to 1 top. I have considered upgrading from the xti4002 to the xti6002. The main reason I have read about the risk of running your amps in bridge mode. Second reason is it is simpler for me to hook up in stereo mode.

[Audiopile]

If I may ask: What are you using your system for?

[RoadRanger]

I disagree with the ratio of subs to tops.

I did qualify my statement with "hereabouts in the land of lead kick". Sure, if you're not running your subs 6-10db hotter than your tops 1:1 is fine . The OP did say he was running out of the subs first so I assume he's running "hot" or outdoors.

 

And BTW I have four different pairs of "subs" that I use with my pair of RCF 310A's depending on the venue:

RCF 600S (300w 1x12)

GK 212MBE (600w 2x12)

Danley TH-Mini's (700w folded horns)

Rog 186 (800w folded horns)

 

Each is about 2x the output of the previous, the latter two can do "hot" with those tops indoors and outdoors respectively. The GK's get used most because they are 34lbs each and do pretty well clustered for 200+. Tomorrow night I might take the RCF 600S as I'm doing a horn band in an intimate room (~100 cap) and we're shooting video and doing a separate live stereo mix for the video and need to keep the low end down so I can mix in the high-isolation headphones (which isolate low end poorly).

[Tomis17]

I do a four piece band indoors. We do weddings, graduation parties, and other holiday celebrations with crowds of 300-500 people. We've never done outdoor events and I don't foresee an outdoor event any time soon.

[Craig Vecchione]

Roadranger: I am feeding 3200 watts @ 4 ohms into two subs (8 ohms each). The subs are rated at 800/1600/3200. Agedhorse: I will create new presets with those recommended settings. Thanks! CraigV: How could I avoid the cancellation in the future?

 

You can't really avoid cancellations and buildups in various locations within a room...it's room acoustics. Note that you'll hear a cancellation (sound drops out) of a given frequency in one area, and it may build in another spot. If you adjust EQ to increase response in the dropout area, you've also increased the normal and buildup areas of the room, so the net effect is zero. Room acoustic treatments are the true "fix", but the "workarounds" are:

1. Adjust speaker position and location if possible

2. Reduce volume to the minimum needed to do the job. The problem is caused by sound reflecting off various room surfaces, so less volume = less reflection = less cancellation and buildup.

3. Use more speakers on delays around the room. This is really just a way more complicated and expensive version of #2...you can get the same effective volume in a given listening area with lower levels by placing speakers close to the listeners.

[jlb]

My go to wedding rig is two SRX 712/718 powered by Crown ITech 6000. Getting ready for a 350 person tent wedding tomorrow!

[agedhorse]

Your rating is not RMS, continuous and maximum. It's RMS or continuous, program (generally defined as 2x RMS) and peak which us generally taken as 2x program only because it's a unit change. Peak is just a math conversion from one type if unit yo another. If your power amp is 1000 watts RMS, it's also 2000 watts peak. Beware when choosing your power amp to understand the rating conventions.