Members jlb Posted August 21, 2012 Author Members Share Posted August 21, 2012 Funny guy LOL My partner and I were the only sober ones within a 5 mile radius. The ambulance came for the drummer of the opening band at 4:30am. It was crazy. The drummer was the drum tech for a national old school act who died exactly a year ago on the same day. This guy stopped breathing and almost died on my sisters front lawn. Yikes! Link to comment Share on other sites More sharing options...
Members RoadRanger Posted August 21, 2012 Members Share Posted August 21, 2012 Ouch! My comment was about the video being too dark to see your rig. I'd sure like to see all them subs set up outdoors . Link to comment Share on other sites More sharing options...
Members mkfs9 Posted August 21, 2012 Members Share Posted August 21, 2012 hey i run 4 srx718's sometimes so what can you safely put into them. Usually i put 1000 in each using a peavey 4080. but sometimes i have to use 2 pl230 and bridge them but then i watch those clip loghts very closely. Link to comment Share on other sites More sharing options...
Members RoadRanger Posted August 21, 2012 Members Share Posted August 21, 2012 hey i run 4 srx718's sometimes so what can you safely put into them. Usually i put 1000 in each using a peavey 4080. but sometimes i have to use 2 pl230 and bridge them but then i watch those clip loghts very closely.600 (maybe 750 if you're feeling lucky) if you want them to last more than a year or two. I'd watch the clip limit lights on that 4080 real close too . Link to comment Share on other sites More sharing options...
Members drumstix Posted August 21, 2012 Members Share Posted August 21, 2012 There was a post or thread in the old PSW forums that several of those involved were taking measurements with several subs but mostly the SRX718. I believe Art Welter was one of those involved. If I remember correctly, they found that anything over 1000w-1100w was starting to show distortion. 900w seemed to be a happy target. I haven't read that thread is a long while. Using a IT12000 on these subs is really a waiste of money. If your buddy didn't have a dealer lic. and access to this gear at his cost I wonder if his story would be different. Heck, as of late I've been using an old Crown CE4000 on a pair of 718's! I'm pleasantly surprised that 600w is fine for me in my small time venues. I think your It6000/4000 amps are fine. The newer HD amps might have some more up to date software, but I don't know if that's worth a swap though. Link to comment Share on other sites More sharing options...
Members minn12 Posted August 21, 2012 Members Share Posted August 21, 2012 Assuming the OP is just running two 728's off an IT6000 that's already 3 kw each . Most people who run the 728s at the pro/large festival level put at least 3200 watts into them, and some run a lot more. There must be a reason why so many pros do this. Link to comment Share on other sites More sharing options...
CMS Author Craig Vecchione Posted August 21, 2012 CMS Author Share Posted August 21, 2012 Most people who run the 728s at the pro/large festival level put at least 3200 watts into them, and some run a lot more. There must be a reason why so many pros do this. 1) Is this fact or opinion? There's a difference, and it matters. 2) How do you know that 3200 watts is ever delivered to the speaker? The possibility that the amp has 3200 watts doesn't assure this. Limiters can be a significant factor. 3) "Pros" or anyone with the financial means to repair the results of an unfortunate accident can overpower cabinets without being put out of business. They can take the calculated risks involved. Can you afford to replace $700 drivers x however many you blew up? If so, then by all means go for it. Realize that the rewards don't really match the risk. Power compression gives you much less volume than you may assume, and you severely decrease driver life expectancy. Link to comment Share on other sites More sharing options...
Members agedhorse Posted August 21, 2012 Members Share Posted August 21, 2012 Most people who run the 728s at the pro/large festival level put at least 3200 watts into them, and some run a lot more. There must be a reason why so many pros do this. Some do have this kind of power available, and when operated with proper limiting algorithems, high pass filtering, and especially having enough rig for the gig, the outcome can be just fine. Note that most of the folks here do not fall into this catagory and driving the piss out of the cabinets because there's not enough rig, without having the proper processing (and verified that it's working correctly), and don't have the experience not to make stupid mistakes and lapses of good judgement. Note that proper limiting can reduce the effective power that the speakers see under high drive conditions, it's an essential part of the overall pro equation. The difference can be another dB or two in SPL but that's about it. IMO, for MOST users, this is not worth the added risk. I have seen the effects of a couple of pro users who have gon beyond what was safe, the result is recone time. The costs are substantial but more easily handled by their increased cash flow. Link to comment Share on other sites More sharing options...
Members agedhorse Posted August 21, 2012 Members Share Posted August 21, 2012 Note that power compression on the differential drive speakers is a little different and IIRC happens in 2 seperate stages depending on the relative positions of the two voice coils and the respective magnetic circuits. It's one factor in why the drivers are more robust but that comes at a slight cost to large signal efficiency. Link to comment Share on other sites More sharing options...
Members minn12 Posted August 21, 2012 Members Share Posted August 21, 2012 1) Is this fact or opinion? There's a difference, and it matters.2) How do you know that 3200 watts is ever delivered to the speaker? The possibility that the amp has 3200 watts doesn't assure this. Limiters can be a significant factor.3) "Pros" or anyone with the financial means to repair the results of an unfortunate accident can overpower cabinets without being put out of business. They can take the calculated risks involved. Can you afford to replace $700 drivers x however many you blew up? If so, then by all means go for it. Realize that the rewards don't really match the risk. Power compression gives you much less volume than you may assume, and you severely decrease driver life expectancy. Here are some real-world users, and what they power their SRX728s with......(see comments) so I guess it's 'fact' and not 'opinion', unless you think all the users are making it up. No reports of any problems running those subs at those power levels. Most people who can afford SRX728s are likely not inexperienced, and don't have problems powering them properly. That's why I said 'pros'. http://www.facebook.com/#!/photo.php?fbid=10150979865201283&set=a.173817121282.132706.173813726282&type=1&theater Link to comment Share on other sites More sharing options...
Members agedhorse Posted August 21, 2012 Members Share Posted August 21, 2012 Here are some real-world users, and what they power their SRX728s with......(see comments) so I guess it's 'fact' and not 'opinion', unless you think all the users are making it up. No reports of any problems running those subs at those power levels. Most people who can afford SRX728s are likely not inexperienced, and don't have problems powering them properly. That's why I said 'pros'. Note that I fall into the pro catagory and I do not do this. I also repair the speakers of those who do and it earns me quite a nice living. To each his own, but I don't think your attitude towards those who disagree with you is justified from somebody relatively new to our community. Link to comment Share on other sites More sharing options...
Members minn12 Posted August 21, 2012 Members Share Posted August 21, 2012 Note that I fall into the pro catagory and I do not do this. I also repair the speakers of those who do and it earns me quite a nice living. To each his own, but I don't think your attitude towards those who disagree with you is justified from somebody relatively new to our community. Well, I respect many of the contributors on this board, but it does seem sometimes that if you post an opinion or facts not shared by some here, your credibility is questioned, and you are assumed not to know what you are doing. So I guess it goes both ways. But it's all good, and part of a robust community where hopefully all opinions are respected. Link to comment Share on other sites More sharing options...
Members mkfs9 Posted August 21, 2012 Members Share Posted August 21, 2012 600 (maybe 750 if you're feeling lucky) if you want them to last more than a year or two. I'd watch the clip limit lights on that 4080 real close too . That seems really low not even rms rating. There seems to be a lot of different ideas on powering these subs. Link to comment Share on other sites More sharing options...
Members RoadRanger Posted August 21, 2012 Members Share Posted August 21, 2012 Depends a lot on what frequency you're driving them at. Most drivers are damaged by over-excursion and not burnout. Within its "flat" band a driver will move twice as far at half the frequency at a given drive level ( somewhat simplified. void where prohibited, YMMV ). Setting you HPF at higher than the cab's recommended value can let you get away with a little more power. Ideal is frequency sensitive limiting such as most powered cabs use these days. You pretty much have to be a rocket scientist AND a brain surgeon ( like AH here ) to properly set up an outboard DSP to let you use higher power levels. The DSP in the iTech's is much more foolproof as it knows exactly what the end of the signal chain is seeing so if you use proper factory presets ( some of the JBL ones are FUBAR, BTW ) you can maximize the performance of your cabs safely . For the OP - if your iTech DSP peak values are already at the recommended values a bigger iTech won't put any more power into your cabs and is a waste of money. Link to comment Share on other sites More sharing options...
Members mkfs9 Posted August 21, 2012 Members Share Posted August 21, 2012 I allways use a 40hz low cut when using the 4080 and a 50hz when i have to use my qsc pl230's bridged. how does that sound. Link to comment Share on other sites More sharing options...
Members RoadRanger Posted August 21, 2012 Members Share Posted August 21, 2012 As a side note sub drivers run past their XMAX create harmonic distortion that sounds good and "punchy" to most folks so the reports of a cab "wanting" or "waking up" at or past a certain power level have some basis in fact. Problem is the suspension will rapidly wear out and get "flabby" and the perceived increase in sound volume and quality will be short lived as the driver is no longer "tuned" to the cab - hence the reason why "those" folks sell off their old cabs and get new ones yearly . "I love the sound of abused subs in the morning!" Link to comment Share on other sites More sharing options...
Members RoadRanger Posted August 21, 2012 Members Share Posted August 21, 2012 I allways use a 40hz low cut when using the 4080 and a 50hz when i have to use my qsc pl230's bridged. how does that sound. Link to comment Share on other sites More sharing options...
Members jlb Posted August 21, 2012 Author Members Share Posted August 21, 2012 Depends a lot on what frequency you're driving them at. Most drivers are damaged by over-excursion and not burnout. Within its "flat" band a driver will move twice as far at half the frequency at a given drive level ( somewhat simplified. void where prohibited, YMMV ). Setting you HPF at higher than the cab's recommended value can let you get away with a little more power. Ideal is frequency sensitive limiting such as most powered cabs use these days. You pretty much have to be a rocket scientist AND a brain surgeon ( like AH here ) to properly set up an outboard DSP to let you use higher power levels. The DSP in the iTech's is much more foolproof as it knows exactly what the end of the signal chain is seeing so if you use proper factory presets ( some of the JBL ones are FUBAR, BTW ) you can maximize the performance of your cabs safely . For the OP - if your iTech DSP peak values are already at the recommended values a bigger iTech won't put any more power into your cabs and is a waste of money. Each SRX 728 has a Peak limiter set between 100-120volts depending on the gig and 800 watts on the RMS limiter. I have heard from some that the peak limiters are not all that accurate. I need to take some measurements to confirm this. When I asked JBL and Crown a while back their recommendations were to set the peak limiter at 160 volts! Link to comment Share on other sites More sharing options...
Members agedhorse Posted August 21, 2012 Members Share Posted August 21, 2012 I allways use a 40hz low cut when using the 4080 and a 50hz when i have to use my qsc pl230's bridged. how does that sound. At 50hz you are trading off lf extension for power handling and increased reliability, part of the performance trade off equations we work with when developing presets. Depends on who is willing to eat warranty costs. Link to comment Share on other sites More sharing options...
Members dboomer Posted August 21, 2012 Members Share Posted August 21, 2012 The amount of power "available" and the amount "delivered" by a power amp are very different things ... that's why speakers have a "program Watts" rating. Typically if you are driving regularly into the amp's built-in limiters you are "delivering" about 10-30% of the continuous average power that the amp is rated at. So I would expect that a 3200W amp is likely delivering about 300-1000W of continuous power and at the same time delivering peaks of about 6000+ Watts. Most power amps will likely only run for a couple of seconds if you ever managed to actually output their full rated continuous power. The thing about speakers is that they likely deliver about 95% of their maximum possible SPL level when they are powered at about half of their rated continuous power. Link to comment Share on other sites More sharing options...
Members RoadRanger Posted August 21, 2012 Members Share Posted August 21, 2012 Each SRX 728 has a Peak limiter set between 100-120volts depending on the gigWhy is that gig dependent? I'd not exceed 160V but I'm sure AH will recommend lower . Link to comment Share on other sites More sharing options...
Members RoadRanger Posted August 21, 2012 Members Share Posted August 21, 2012 The thing about speakers is that they likely deliver about 95% of their maximum possible SPL level when they are powered at about half of their rated continuous power.It's not clear what you meant by this? Assuming a 800w driver are you recommending a 400w amp or that fudged by the 10%-30% you mentioned so an amp rated between 1333 and 4000 watts? I do agree that there is no benefit in putting more than 400 "real" (AKA thermal) watts into it . Link to comment Share on other sites More sharing options...
Members jlb Posted August 21, 2012 Author Members Share Posted August 21, 2012 Why is that gig dependent? I'd not exceed 113V but I'm sure AH will recommend lower .That's kinda low - unless you mean "per driver" where it would be about right? (I'd use 400w for each though, see below) If I am renting equipment PEAK limiters are set to 100 volts. If I'm running the equipment they are set at 120v. It has been recommended by more advanced users to set the RMS limiters at half the the ratings of the cabinets. Link to comment Share on other sites More sharing options...
Members dboomer Posted August 21, 2012 Members Share Posted August 21, 2012 It's not clear what you meant by this? Assuming a 800w driver are you recommending a 400w amp or that fudged by the 10%-30% you mentioned so an amp rated between 1333 and 4000 watts? I do agree that there is no benefit in putting more than 400 "real" (AKA thermal) watts into it . A 400W amp would never put 400W "into" a speaker in the normal course of things. The speaker would have less distortion if you "delivered" 400W from a 4000W amp ... assuming less distortion in a sub is a good thing (which as you pointed out above isn't always a good thing;) ) What do I do? The last "big" system I built had sixteen double 18" sub cabs each driven by a separate Crest Pro 9200 that was bridged. As I remember that's a potential of about 6500W per cabinet. I don't think we smoked any of them during the 40 show tour they were built for. But there was a butt-load of DSP processing going on making certain of that. I don't think this relates to very many users on this forum (who actually have to pay for their own gear:love: ) That was then ... now I use self-powered double 12" sub cabs and the audience size goes down a bit! Link to comment Share on other sites More sharing options...
Members jlb Posted August 21, 2012 Author Members Share Posted August 21, 2012 I agree with that (as I said) but those cabs are 1600w so 1/2 that is 800, no? Why do you set them at 600? Typo sorry. I meant 800w. Link to comment Share on other sites More sharing options...
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