[Lineman26]

I need ideas on what might be the cause of this issue my buddy is having with his system I’ve installed and continue to upgrade as he get new equipment. 2015 Infinity Q50, originally I installed an Alpine dsp along with a active 3 way front system, 6 channel Crecendo amp, real fill and subs. First speakers to go were both Morel 2.5” dome mids that were maybe 6 months old, going within a couple days of each other. A Steg tweet, both Focal Flax tweets were toast within a month, a high end set of Pioneer tweeters lasted less than a month, and a couple months ago he finally took my advise and got the Hertz Mille Legend ML280.3 tweeter ML700.3 3” and ML1800.3 7” setup and let me move the tweeters from behind the small plastic factory grills on the doors to a-pillar pods. I had installed the same setup a couple of times in other cars and with those 3” and tweeters in the pillars and dash locations they can nearly make your ears bleed without breaking a sweat. After the first 2 or 3 sets blew, He had me add a set of 2.2k caps to the tweeters as an extra backup to the 2k setting on the amp and 2.5k setting on the DSP. I also swapped the Crecendo 6 channel out for the Audio Control 6 channel and ran dedicated wires straight from the amp to the speakers, trying to eliminate any possible causes. Last week we swapped out the Alpine DSP for a Helix 10 channel as one of the RCA jacks on the Alpine was noisy and required a ground to be soldered on to eliminate it. Anyway, he called yesterday and one of the Hertz tweeters wasn’t working, and sure enough I checked today and it’s completely dead. He doesn’t over cook his system and knows it’s limits so I don’t think it’s him and the volume knob causing it. I originally thought that because the stock grills had such small holes and not many of them that the tweeters were actually getting overworked and we just weren’t getting enough sound past the grills, and every tweet prior to today had a power rating of 25 to maybe 40 watts RMS, and the combination of the much bigger and beefier Legend tweeter in a pod right in your face with probably double the power handling had me convinced it wouldn’t happen again. I know tweeter power rating are wushy washy, but I even moved the mid/tweet crossover point to 4k when I installed the Helix DSP to compare the sound. Any ideas of what might be causing this rapidly growing graveyard of tweeters??? TIA

 

[Lineman26]

Gains are all set properly, crossover points were all set at or above what the included crossovers had that came with the speakers or what the manufacturer recommended. I know I haven’t been working as an installer since 09, but for the 12 years I did spend doing it every day, plus the other 20 years that I have done it as a hobby and side gig, I never claimed to be or even tried to be one of the fastest guys in the bay, but there might have been one quarter that I didn’t have the lowest rate of service jobs come back, usually by a significant amount. I’ve installed well over 1000 amps, a similar number of speakers and everything else that goes with them… The gains, crossovers, settings etc were the first things that I rechecked after the first speakers died, and they have been rechecked, set, lowered…. I still to this day have to have the “gain controls are not volume or power level adjusters” conversation with people all the time. One buddy always wants his stuff set up so it’s loud, like maxed out at volume 15 out of 30 or 40. For 10 years and at least 6 big systems they have been that way. One tweeter and one old worn out 13w7 is all he has killed and he is all rap all loud all the time. If it was gains or clipping I wouldn’t be here asking for ideas.

 

[Lineman26]

Ok I sorta knew that it may go this direction but I’ll list all the other stuff and explain how I set it up.

the owner of the car had previously installed one of those giant screens/android based tablet head unit systems that are becoming more common for newer cars, as his stock dash had two smaller displays, and now he has a giant Tesla type. It’s basically a vehicle specific plug and play that works with the stock amplified 15 or 17 speaker system. Unfortunately no rca outs for any aftermarket add one. Sub amp is a DS18 KO3 3k running either a single ported Ampere Audio Neo 12”, a ported B2 Rampage 12”, 3 B2 Audio Rampage 8”’s ported or his new as of last week Rockford T2 13” I’ve made both a sealed and ported box for. I’ve made all the other boxes as well. He likes to try different subs. And he was doing it with the front speakers to which is why I was pushing him to try the Hertz plus letting me move the tweeters and 3” from the stock door locations to the a-pillar and dash. Electrical is all upgraded. I installed a 260 amp alt, all good 0 guage power grounds with an XS battery under the hood and a XS lithium battery in the trunk. I installed the module for the alternator so it charges all the time and has the voltage control which is typically set at 14.6-14.8, and rarely dips below 14.
I specifically set the tweeter/midrange crossover points slightly higher than what the specific crossovers that came with the speaker set used, or if they were bought as drivers only like the Hertz I set them slightly higher than what the manufacturer recommended. This was set in the DSP. I also set the HP on the amp as a “backup” in case the dsp settings crashed or got changed somehow, and set them about 200hz below the dsp setting. After a couple dead speakers he had me throw in a set of caps on the tweeter leads, which I think are 2.2k at 4 ohm, possibly 2.8k, but by that time I had already gone up close to 3k on the base crossover point also. All are 24db linkwitz. I originally set the amp gains the same way I’ve done it more than 1000 times. One at a time, volume 3 to 4 notches below max, starting at minimum go up to any sign it’s close to clip/distortion, then I back off quite a bit. I always run gains low, like normally it’s hard to find any track that can’t be played all day at max the volume setting. I do know that the owner likes to tinker with settings and stuff but I always check and have never found anything that could be an obvious cause that had been changed. I have checked them with a scope, albeit a cheap one, but never saw any flat spots. I do know that he can play music from the head unit or via Bluetooth from his phone to the head unit or the dsp and he has now also picked up a portable hi-res player that will be hard wired to the Helix and will be what he regularly uses. I thought maybe the different input options could have something to do with it ?? The one area that I don’t have much experience is tuning the more complex dsp systems with multiple input sources as the very first versions were just being released when I quit working with 12 volts to work with 26,000 volts, so while I understand what the different setting and features are, I’m a total noob at being efficient at the setup and tuning portions. Around the same time that I installed the caps on the tweeters we also swapped the Crescendo 6 channel for the current non DSP Audio Control 6 channel, which I believe is rated at 120x6 at 4 ohms. Then last week I pulled the Alpine DSP out and installed the Helix DSP Pro MK2 and Director, which has had us learning a new software system and setup. The current Hertz speakers have been installed for a little over 2 months, and I did the direct amp to tweeter wire at that time, and those tweeters have always been set above 3.5k. Just today I eliminated the stock front tweeter signals that had been used as the source signal for the high frequencies when I originally installed the Alpine a few years ago and now have all the mids and tweets using the rear door speaker output signal from the stock amp. I have both the rear doors and stock sub signals summed as the subwoofer input. I thought that maybe there was some issue with how the dsp’s were connected to the cars system as that’s the one thing I’m not well versed in….

 

[Lineman26]

Ok I got back over to look at the car last night so I could once again check the crossover points and gain levels that somehow I had done successfully without issue for 30 years but obviously I either forgot how or maybe Ithe first 1000 times I just got lucky. The HP setting on the amp outputs was set at 3300hz, and the DSP setting was at just over 3600hz, 24db slope linkwitz. Amp gains were right at 1/4 for the tweeters and 3”just over half for the 7” channels. I copied this from Hertz “power rating, 180W Peak (Hi-Pass filtered @ 1,8kHz - 12dB Oct.) which is why I felt going twice as high as the 1.8k with double the slope should be plenty safe, but apparently combining those settings with the amp being pegged at 25% I need to put my tools away forever and never install tweeters again…. When I put the scope on it I wasn’t seeing any signs of clipping/ distortion until close to 75% on the gain setting. I’m such an idiot for not thinking the power might be an issue, but right around the time I installed the majority of the stuff, or a bit after I remember a thread where an endless number of people were commenting on how they would give their left nut, if not both to have the Brax MX4 amp powering their 2 way active front setups, and I even questioned some that were saying how it’s was common for people to use that big 300 x 4 amp with Focal Utopia tweets and 6.5” mids, and while I was the only person that seemed to think using 300 watt rated channels to power 20 watt tweeters was even slightly overkill, every other comment was another person offering up their life savings plus their wives and kids to own or just spend an hour with that setup. Lol. And because my buddy who owns the car has a 3k sub amp and has several different subs/enclosures that have spent time in the car I guess it’s obvious to some people here what the problem is…

 

[Lineman26]

Good eye/catch/reading. I just can't imagine someone enjoying listening that loud. If the vehicle is used for doors open SPL shows, okay, but not sitting inside for any SQ purposes.

neither this vehicle or the one I did before that I was taking about get played at unusually high volumes but because they have the ability to play higher than the average SQ fan would need points to the problem I guess? Or it’s the fact the dude likes ported boxes and has a big sub amp? I’m learning new stuff all the time

 

[Lineman26]

Gain knob doesn't work that way. It's not a volume control. Should have used the DMM method with the oscilloscope for the tweeter. Then still turned it down several db at the DSP. Aftert that play music at "full tilt" volume then either turn it up or down at the DSP depending on the desired output. Tweeters don't need alot of power. Then if you are tunning to a curve they'll use way less.

You must have missed the part where I checked them with a scope at the setting they were at, about 1/4 up from minimum, and the first time any signs of distortion or clipping showed up was at or a little above 3/4 to max level. I have set up every system that I’ve done for myself or someone else the same way unless the customer specifically wants something set different, but I normally set them back far enough that the volume can be maxed out with useable sq still. Some guys like to get to 75%, I’ve done several for a guy who I know already that he wants his to be maxed at 1/2 volume. He is the one I’ve been trying for 10 years to understand that lower settings sounds better and cranking up the gains don’t add power.

 

[Lineman26]

As long as they're outside of the passband of the crossover: not really. Having cascaded filters as close to one another as OP does will change the acoustic slope of the crossover which will result in improper summing. You primary fail safe should be a capacitor higher than the resonant frequency of the tweeters. 1.5-2x will offer more protection in case you don't remember to turn an XO on. A cap will also protect against an amplifier fault which could send DC to a tweeter and kill it.

So you’re saying that if the DSP hp is set at 3600, having the amp hp set as close as 500-750hz lower would change the slope in a negative way? But the 2.2khz caps I added would be fine being the fs of the tweeters is 900hz? So no amp crossover, turn it to full range?

 

[Lineman26]

You already said it - volume is cranking at 15 out of 30. The gains are too hot.

not on this car. Volume can be pegged and output is considerably lower than other systems with same speakers and far lower than what it should be capable of.