Members mental-mike Posted September 28, 2009 Members Share Posted September 28, 2009 hey folks, so...our singer bought 2 new 4000 europower amps Anyway, we are pushing Peavey SP4 {I think} they are 2-15s w/horn rated at 2000..they ran fine as the amp for that was ran left/right NOW...the SP 118s is whole new story....they are rated 800 at 8 ohms...it was ran with the 4000 in BRIDGE MONO, w/banana clips "stacked" or plug in one, then the other INTO it. 3 songs into the set, that famous electrical smell starts...we loose stage right 18...singer unplugs it...and we make it through all 3 sets with the other 18. From what I could see, we never clipped the amps, in fact, the subs amp was only at the 10-11 o'clock position so it wasn't really even being pushed at all. I understand too much power will kill speakers, but why did it only kill the 18 closest to the rack and not the other one? And, if we are not pushing the amp hard...does the power become an issue? thx in Advance Link to comment Share on other sites More sharing options...
Members monkeyland Posted September 28, 2009 Members Share Posted September 28, 2009 you should do some reading. there has been quite a lot of discussion over the last few days about this. you should also clarify which sp118 you are using. the specs have changed slightly over the years. Link to comment Share on other sites More sharing options...
Members gspointer Posted September 28, 2009 Members Share Posted September 28, 2009 I would call it dumb luck that the other didn't blow. You were running 2k into 600 watt speakers, fix the blown sub, run your amp in stereo. Link to comment Share on other sites More sharing options...
Members jwlussow Posted September 28, 2009 Members Share Posted September 28, 2009 Bridged mono is alway dangerous unless you REALLY know what you are doing. My guess is you have unmatched SP118s. One is a 4 ohm cab and the other is an old 8 ohm cab. The specs have changed over the years. The knobs on the amp do not control the output. They control the input sensitivity. As you found out, it is possible to fry speakers even with the input settings at 10 - 11 o'clock. There are others here much more qualified to help you out. I have heard of different versions of the SP subs. That is where I would look first. Link to comment Share on other sites More sharing options...
Members agedhorse Posted September 28, 2009 Members Share Posted September 28, 2009 The other speaker may also be damaged, you just don't know the extent. There are tolerances and thresholds that define ultimate failure. Even 20% is not uncommon and that can be accounted for in a long run of undersized speaker wire. Those of you running big power should take note here, another good example. Link to comment Share on other sites More sharing options...
Members Mogwix Posted September 28, 2009 Members Share Posted September 28, 2009 I understand too much power will kill speakers, but why did it only kill the 18 closest to the rack and not the other one? And, if we are not pushing the amp hard...does the power become an issue? It seems quite apparent that yes, you don't need to push an amp for power to become an issue. The amplifier is much too powerful for the speakers, so it easily exceeded their capabilities. You mentioned that the sub amp was at "only at the 10-11 o'clock position", but you need to realize that the input attenuators on the front panel don't lower the amplifier's gain, only attenuate the input signal (as the name would imply). This means that it's still entirely possible to "push" the amplifier to full power and beyond, even with the amp "turned down". I would suggest you get your subwoofer repaired, replace the amplifier with one properly matched to the subwoofers, run it in stereo, and check your gain structure. Link to comment Share on other sites More sharing options...
Members mental-mike Posted September 28, 2009 Author Members Share Posted September 28, 2009 Thx again for the reply s...I am reading up on other post about blowing {censored} up here at the specs for the SP 118 that our singers owns So 600 watt continuous... I'm assuming bridge mono was a bit too much Power Handling: 600 Watts continuous 1,200 Watts program 2,400 Watts peak 8 ohms Link to comment Share on other sites More sharing options...
Members dboomer Posted September 28, 2009 Members Share Posted September 28, 2009 ran with the 4000 in BRIDGE MONO Where did you have the high pass filters set? Far more likely it was too low a frequency than too much power. Link to comment Share on other sites More sharing options...
Members agedhorse Posted September 28, 2009 Members Share Posted September 28, 2009 Where did you have the high pass filters set? Far more likely it was too low a frequency than too much power. I would suggest that the HPF may be a contributing factor, but that's way too much power for the mechanical limits too, even with a HPF. You can't rely on common sense in these scenarios IME, reasonable operation is not usually likely when an amp is purchased that is so inappropriately matched when operated in bridged mode. What were they thinking? Maybe they took some poor manufacturer advice? Link to comment Share on other sites More sharing options...
Members mental-mike Posted September 28, 2009 Author Members Share Posted September 28, 2009 Where did you have the high pass filters set? Far more likely it was too low a frequency than too much power. Just got of the phone with the singer, he had ALL the dip switches to the right..he has BOTH amps like this..1 drove the sp118s, the other driving the SP 4 2-15s. so low cut was at 30hz, but looking at the manual online..it shows he had the low cut OFF also... We {the band} have said for MONTHS to hire a sound guy for one night to setup the PA CORRECTLY and mark it with a sharpie...but being a hard head..it's the "we can get it right" {censored}.... Also, he's not using the compressor/gate and the crossovers, we had an issue with the last amps he had that smoked from yrs of abuse...so he bypassed that stuff thinking it was causing some odd sound issues. Link to comment Share on other sites More sharing options...
Members soul-x Posted September 28, 2009 Members Share Posted September 28, 2009 All switches to the right disengages the HPF. Link to comment Share on other sites More sharing options...
Members soul-x Posted September 28, 2009 Members Share Posted September 28, 2009 BTW, I half-hazardly modeled cone excursion for that box at your wattage levels for another thread last week. It's not 100% accurate, but at least somewhat representative of what you can expect Take a look at the left hand side of the graph to see what happens to cone travel at those power levels below the tuning frequency of that box. Y axis units are in inches and xmax is indicated by the red line. Unloading that (or any) driver at 1200w is not pretty. The HPF is an absolute necessity with the type of power we are discussing. Link to comment Share on other sites More sharing options...
Members agedhorse Posted September 28, 2009 Members Share Posted September 28, 2009 Look at what happens at 50-70Hz too. Link to comment Share on other sites More sharing options...
Members agedhorse Posted September 28, 2009 Members Share Posted September 28, 2009 Just got of the phone with the singer, he had ALL the dip switches to the right..he has BOTH amps like this..1 drove the sp118s, the other driving the SP 4 2-15s. so low cut was at 30hz, but looking at the manual online..it shows he had the low cut OFF also... We {the band} have said for MONTHS to hire a sound guy for one night to setup the PA CORRECTLY and mark it with a sharpie...but being a hard head..it's the "we can get it right" {censored}.... Also, he's not using the compressor/gate and the crossovers, we had an issue with the last amps he had that smoked from yrs of abuse...so he bypassed that stuff thinking it was causing some odd sound issues. A grand case of the stupids all around. The gates/comps aren't going to help if the basic problem and situation isn't fully understood. Just having them isn't going to help, they need to be properly calibrated (limiters) to work. Best bet is to operat the amp on the subs in stereo with the limiters and HPF engaged. That's ok power levels with no calibration required. Link to comment Share on other sites More sharing options...
Members soul-x Posted September 28, 2009 Members Share Posted September 28, 2009 Look at what happens at 50-70Hz too. Yeah, I personally wouldn't choose to power my stuff that way without some reasonable processing, but the failure definitely wouldn't be as instant or catostrophic as what happened to Mental-mike. Link to comment Share on other sites More sharing options...
Members Tripper Posted September 28, 2009 Members Share Posted September 28, 2009 I wonder if it would have happened if the HPF was engaged? Link to comment Share on other sites More sharing options...
Members monkeyland Posted September 28, 2009 Members Share Posted September 28, 2009 I wonder if it would have happened if the HPF was engaged? not to mention if it was crossed over. he mentioned that the crossover was bypassed. full range input into a speaker that can't put out anything way up high anyway. Link to comment Share on other sites More sharing options...
Members Tripper Posted September 28, 2009 Members Share Posted September 28, 2009 not to mention if it was crossed over. he mentioned that the crossover was bypassed. full range input into a speaker that can't put out anything way up high anyway.True. My crossover is set from 35 Hz to 100 Hz for my SP118s. I wonder if I should go up to 40 Hz? Link to comment Share on other sites More sharing options...
Members monkeyland Posted September 28, 2009 Members Share Posted September 28, 2009 True. My crossover is set from 35 Hz to 100 Hz for my SP118s. I wonder if I should go up to 40 Hz? mine are running with the built in crossover on the GX5 which is 100hz as well as the hi-pass on my graphic engaged which is 40hz and it's working fine. Link to comment Share on other sites More sharing options...
Members Shaster Posted September 28, 2009 Members Share Posted September 28, 2009 As AH has stated, why would your singer buy such over powered amps? I'm so mystified, I'm gonna log out and finish my house painting. 4000 watts, really? Link to comment Share on other sites More sharing options...
Members mental-mike Posted September 28, 2009 Author Members Share Posted September 28, 2009 As AH has stated, why would your singer buy such over powered amps? I'm so mystified, I'm gonna log out and finish my house painting. 4000 watts, really? Well, the thought behind it was this....He was under powering the SP4 2-15s and finally blew the amp for that, it gave us yrs of good shows, so he got a "deal" on the euroamps....2 4000's for a few hundred bucks. The thought behind it was using one channel to run the SP4s and the other to push the sp118s...then he finally went with 1 4000 to run the SP4's left/right and use the other 4000 to push the sp118s....didn't think it would hurt to push it in bridge mono the "theory" behind the thinking was, not having to drive the amp on full, like the old one....figured since it was only running about 1/2 on the level it wouldn't be bad.....guess that theory is out the window now Link to comment Share on other sites More sharing options...
Members soul-x Posted September 28, 2009 Members Share Posted September 28, 2009 I wonder if it would have happened if the HPF was engaged? Good question. Mental-Mike -- Fortunately for you, the Pro Rider basket is fairly easily user replaceable. If you could entertain us by snap a few pictures of the spent unit at time of replacement, we can have a little forensic discussion on the actual failure mode of the drivers for the benefit of those here. We'd appreciate it. Based on the narrative it sure sounds like there is both a mechanical and thermal component to the failure Link to comment Share on other sites More sharing options...
Members oldschooler Posted September 28, 2009 Members Share Posted September 28, 2009 As AH has stated, why would your singer buy such over powered amps? I'm so mystified, I'm gonna log out and finish my house painting.4000 watts, really? Because big amps are cheap now a days. People buy more then they need just in case of an upgrade. Link to comment Share on other sites More sharing options...
Members dboomer Posted September 28, 2009 Members Share Posted September 28, 2009 so low cut was at 30hz, but looking at the manual online..it shows he had the low cut OFF also... 30 hz is too low if you expect to be running high power with those speakers. I'd recommend setting the frequency at the -3 dB point of the speaker. Link to comment Share on other sites More sharing options...
Members boseengineer Posted September 28, 2009 Members Share Posted September 28, 2009 BTW, I half-hazardly modeled cone excursion for that box at your wattage levels for another thread last week. It's not 100% accurate, but at least somewhat representative of what you can expect Take a look at the left hand side of the graph to see what happens to cone travel at those power levels below the tuning frequency of that box. Y axis units are in inches and xmax is indicated by the red line. Unloading that (or any) driver at 1200w is not pretty. The HPF is an absolute necessity with the type of power we are discussing. Nice pic but it also warrants some discussion. This shows excursion for steady-state sine waves and it looks like the excursion goes down from 55Hz to 35Hz. That is because at the port tuning frequency, the cone hardly moves and all the air is movement is in the port. However, that's really only true for sine waves that last a long time. It takes a considerable time for the box and the port to build up the resonance. You will see much higher excursions during the onset of a sinewave. Hence anything with real transients in it (for example a kick drum) will produce significantly higher excursion near the port tuning than this picture would predict. Link to comment Share on other sites More sharing options...
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