New info JBL system lower ohms to increase volume

JL audio advertises a low rms sub also for 50 bucks more with the same frequency and is a little less sensitive but low rms I want to test and haven't yet.

 

Boss audio had the most sensitive sub but the highest frequency so it was loud but did not hit low so it's always a trade off

 

I'm not going to spend my Friday night writing a book on electrical theory, speaker design and the the decibel scale. Honestly, that would be a bad idea anyway, I'm more of a digital guy and the analog side of my brain is rather rusty. Other people have gone to great pains to write very good websites on this stuff. It is up to you to go out and educate yourself about how this stuff works. But just throwing things out the window because they're complicated will only lead to more confusion when your theories don't pan out. The math is somewhat complicated because sound and sound systems are complicated. Other people have been pointing at this off and on through the course of the thread, so I'm going to leave it at that.

I was going to try to explain some things thoroughly, but honestly, I just spent solid 45 minutes writing and rewriting trying to come up with a simple, decent, explanation of impedance. Its just not gonna happen without a whole lot more coffee. The super short version is - your multimeter doesn't measure impedance. Ignore what it tells you when you put it across the speaker coils.

As for the efficiency thing, the decibel scale is logarithmic. When it comes to audio decibels, an increase of 10 dB is double the perceived loudness. So the difference between 82 and 91 dB at 1 watt is really pretty big. But those numbers are probably fudged anyway - different manufacturers have different ways of testing it.

Power requirements are also logarithmic. To get double the percieved loudness from a given speaker, you need ten times the power.


As far as whats actually going on here. I think the theory about the amp overheating is solid. I'd love to tear one of those amps apart and try to understand whats really going on. Stepping into complete-guess territory here, I think Toyota would want the most reliable possible system, and they want to use that amp in as many vehicles as possible. So they designed it to fend for itself - to be smart enough to detect overheating and clipping and whatever else, then tell the system to dial it back. That way they can just stuff it in, plug it in, and forget about it. But maybe they don't realize how much its having to dial things back? I dunno. Its a theory. I think I'd play some pink noise, set the volume fairly loud, and then heat and cool that amplifier while measuring its input current. If input current goes down as heat goes up, I think that would prove its doing something.

As far as the speaker itself - just look at the new speaker versus the OEM one. The OEM one is designed to be cheap as possible. And probably reliable, because toyota. You'd have a hard time not improving on it audio quality wise - whatever you replace it with is going to be more efficient, with better power handling.

Maybe the key to making these JBL systems sound good is to just replace all the speakers? Seems like the electronics are decent, but the speakers themselves are crap. And maybe cool the amplifier.

 

After reading every post from the very start I have made my conclusion................... Unless you want to dump a fortune into a whole new system so you can throw some 30 inch chrome wheels , 30 color LED lights and fuzzy dice on the mirror.................. The stock JBL system is perfectly fine.

 

All amazing replies. Seriously. So here we have the ultimate question? How do you fix it? I'm willing to dismantle mine and get the code off the amplifier chip and see what other electronic settings they have installed. Judging by the tiny electrical cord Jack on the amp everything looks able to be plugged in a modified with a PC but I've never seen that cord before. Stereo amplifiers set db and gain electronically per the chip so having the number would open the whole world to what factory presets are there and optional chip replacements. I just need to know the manufacturer and number on the chip.

 

If you change the sub it affects the front door output witch I know are wired in parallel with the tweeters. So what kind of amp is this a mono amp that is driving 7 speakers that act as 1

 

OEM audio calls it the jbl can bus network

 

This has been a very interesting thread with various conclusions brought about to it. Hell even I learned something about the 3rd gen stuff.

For those wanting to venture into new avenues... Ditch it all.. RCA leads from the new aftermarket headunit out get a steering wheel adapter kit to keep the steering wheel controls and possibly some other unit purpose built for the 3rd gen to keep the can bus stuff on the digital dash cluster display. A turn on module to keep the JBL powers and filtered grounds will handle powering the headunit as well as the amplifier turn on at the rear. Two new compact amplifiers and the output speaker leads will suffice just fine. One to drive the speakers a 4 channel will suffice, the other to drive the subwoofer independently. A monoblock unit. Both fit in the recessed area of the OE sub enclosure assembly once all the bracketry is removed and some mild modifications are made to the rear panel. If you have a will to do it there is a way. I ran a SKAR audio SKM5000.1D 500 watt @ 1ohm RMS amp and a Memphis Audio MXA4.45 4 channel amplifier. The setup sounded brilliant with your choice of awesome door speakers. The OE sub enclosure is a solid unit when running a properly sized subwoofer in there. Here is a picture of the setup.



It worked well for what it was but eventually I outgrew it to a real setup. It was a real thumper for it's size though!

For those wanting to retain and attempt to modify and run the JBL setup in attempts to sound better, best of luck.

 

Here's what the factory amp with jbl specs.

 

Nice work trdtacoma and riotfunk! I was planning on fully changing everything but haven't decided what type of music I was aiming at yet. My last car had 2 rockfordfosgate p3s loaded in their enclosure. And last weekend I almost had enough with all these subs availability locally i almost put 2 12 w3s in. Head unit was gonna be halo9 but I guess pioneer is coming out with a 9 in display to give the halo some competition. As for speakers stick with some 2 ohm jbl gto's or some 4 ohm crap I dont know. What speakers do u like? I didnt want to let this thread down on sub selection for those who wanted to stay stock so I'm just sound deadening for now waiting for 2 more subs to show up in the mail tuesday

 

Honestly best bet is to gut. Do headunit, speakers, sub etc. Just annoying and pricey. Easy enough but just doubt feel like doing it I'm gonna throw the sub in when it comes in and just go from there

 

I sound deadened the whole back of the truck and the exterior of the sub box. Put the cerwin Vega back in because the frequency is 34hz instead of the kicker at 40hz. The cerwin vega definitely hit lower. And finally put all the plastics back in and it sounds amazing. Left the fan on the amp still tucked behind the back plastic. So well see how it does. But it sounds really good with the sound deadening. Definite improvment

 

I got the Polk in. Wired to 2 ohms. Needed a little more foam for the surround but right in. Sand down the oem bolt holes, raised a lil. So will sit flush. So far, is far better sound stage than the oem one. Ran for about 15 min driving around with a bunch of different music playing.

 

Got any pics?

 

No pics, sub came late yesterday and threw it in. Gonna have to pull everything again and insulate the back. The bass makes the plastic cover rattle over the sub and amp. Getting bad buzz when bass hits. The plastic lip along the window and the middle part where it doesn't really bolt to anything just moves and rattles. Can take pic when I tear it out again

 

Subd for electrical fires lol

 

Challenge accepted

 

I've been saving a jar for such an occasion.

 

http://www.toyota120.com/forum/showthread.php?t=27059

Maybe toyota has been fooling around with ohms little too much