Bass problem eludes CAR TOYS installers

[Mark97213]

Installed: Alpine Head Unit INE-Z928HD, Alpine AMP PDX-V9-5, JL Audio 13TW5-3, Focal 165 KRX2, FOCAL PC 165. 2011 Chevrolet Silverado 2500HD

I've always had pretty good luck troubleshooting or finding someone that can cure any car audio performance problem but now I have problem that even the pro's at Car Toys can't seem to fix and I'm really at a loss of what to do about it. I was hoping I could get some advice from some on the forum for what I should do next.

This system is everything I need and gives more than I need with great bass output that sounds fantastic when everything is working correctly but, it has an intermittent bass problem. During play, the bass will intermittently drop off for a period of time or just completely dissipate to zero output for as long as five minutes and then, mysteriously come back to normal levels. However, this chain of events will just randomly occur and randomly correct itself.

The system was purchased and installed at Car Toys and has been back to Car Toys, twice, to correct the problem that, either they can't replicate or they say it has been "fixed." However, the problem is intermittent and each time it's been back to them for repair, this issue still remains. They've adjusted the amp, checked connections, changed ground points, etc., all to no avail. They've also said they changed out the amp but I'm not sure they actually did. Their concern for "correcting the issue" is met with skepticism that an issue even exists. Over the years, I've had very good experiences with Car Toys and after several installs, I've always been thrilled with their work but now, with this vehicle, I've hit a wall and I'm not sure how to deal with it and am hoping to get some of your advice.

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[winkychevelle 10+ year member]

Does the amp get hot when this happens could just be the amps isnt cooling enough in whatever tight space u have it shoved in

 

[CaptainMaximus 10+ year member]

Does the amp get hot when this happens could just be the amps isnt cooling enough in whatever tight space u have it shoved in

I agree with this, try monitoring the amps thermal temp, and as soon as that bass cuts out go check everything again. Try this: when the bass goes out, try turning the truck off for a few seconds completely and then turning it back on to see if the bass continues... Best of luck!!

 

[jrdnhsnbrg 10+ year member]

Did they check the fuses? I had a similar issue and it was caused by a corroded fuse causing a weak connection. If you have ever driven in rain with the system it's possible the fuse is corroded. Thermal temp of the amp is probably the first thing to look at, though.

 

[basswiigee]

watch the amp and the protect light... sounds like its going into protect when hot...

 

[Mark97213]

Thank you everyone for your advice on this. I'm right with you in what you're thinking as it does sound like it is a heat issue but ironically, the colder it is, the Worse it performs. I'll see if I can do as you suggested and monitor the temp and lights on the amp. The bass dropout is most prevalent when I first start driving. Audio will be playing fine, approximately 2-3 minutes, and then the drop off in bass. It started from day one after I picked up my truck after the install. It is weird. I don't entirely lose bass, just most (80%) of it. There have been a few instances when the bass returns during a song, that the bass coming back on is turned WAY too far way up and then drops back down to normal output. Occasionally, just prior to the bass returning to normal, it's as if the amp is "hunting" (1-2 seconds) for the right bass output as the output varies so significantly.

 

[Side Show 10+ year member]

errrr... check your battery connections, you may have a weak/poor connection

 

[hip3 10+ year member]

I had a very similar problem a few years back. The RCA inputs on the amp were loose internally. Local amp guy replaced or repaired them. Everything was fine after that. Try jiggling the connection when the problem is present.

 

[garychoffmann 10+ year member]

I'm on my phone so I can't type a whole lot. But the pdx is a constant power amplifier. It is rated at 2 and 4 ohms. A 3 ohm load is skirting its high power vs high current switch over point. The amp draws back power as it switches from high power to high current. The amp is getting confused and that is why you are getting a low power output and then a surge before it settles back down and then the cycle continues. The problem is what is called box rise. Your ohm load changes as music plays. I forget which forum an alpine engineer frequents, but you could probably hunt him down

 

[Side Show 10+ year member]

interesting.... why would it be seeing a 3 ohm load tho?

 

[garychoffmann 10+ year member]

13tw5-3.... the 3 is the ohm of the sub. Unfortunately they only make it in 3 ohm I believe.

 

[Side Show 10+ year member]

true..... wow....in that case ask the shop to duplicate it, then see if they can try a 4ohm woofer as a test to see if this is the entire problem.... they may even try and source a new woofer for you, worth a try

 

[garychoffmann 10+ year member]

Go to car toys in the morning. Ask them to throw a prefab in the seat that rests at 2 or 4 ohms and play it full tilt. If it doesn't have issues, you know your problem

 

---------- Post added at 10:53 PM ---------- Previous post was at 10:53 PM ----------

 

Beat me to it.

 

[Side Show 10+ year member]

HAHAHA onto it!

 

[bbeljefe]

Thank you everyone for your advice on this. I'm right with you in what you're thinking as it does sound like it is a heat issue but ironically, the colder it is, the Worse it performs. I'll see if I can do as you suggested and monitor the temp and lights on the amp. The bass dropout is most prevalent when I first start driving. Audio will be playing fine, approximately 2-3 minutes, and then the drop off in bass. It started from day one after I picked up my truck after the install. It is weird. I don't entirely lose bass, just most (80%) of it. There have been a few instances when the bass returns during a song, that the bass coming back on is turned WAY too far way up and then drops back down to normal output. Occasionally, just prior to the bass returning to normal, it's as if the amp is "hunting" (1-2 seconds) for the right bass output as the output varies so significantly.

That sounds like a cold solder joint and it's not at all uncommon for the RCA assemblies. However, when they have a cold joint, they make gawd awful screeches, pops or hums. I would think it's the power inputs or some other part of the power circuit. And if they did in fact replace the amplifier with another one they had on hand, both could have come from a batch of amps that suffered a manufacturing malfunction on the assembly line or, they could have gotten a bad batch of caps, op amps, et al.

I would be more inclined to try a different brand amplifier than a different driver. All amplifiers are designed to operate properly with a constantly changing impedance, because all loudspeakers are variable impedance devices.