Adding Mono Amp & 10" Sub to JBL 15 Speaker

[Jay Nice]

I have been searching all over the web prior to posting this but I haven't had much luck finding any info about adding additional amps/subwoofers to a "15 speaker JBL setup". There is tons of info pertaining to non jbl, 8 speaker JBL or adding an amp to power the entire set-up.

I think I have everything sorted out for the most part, thanks to [MENTION=65614]Antman[/MENTION] 's subwoofer install/how to, & a few other search queries on this site. The JBL 15 speaker set-up is good but.... the lower end is lacking. I plan on keeping the factory 8" to provide a punch to the mid range.

I believe all I need to do is tap into a pair of speaker wires with a line-out converter (c/w bass control knob) but I would rather add this from the rear speakers. I read somewhere that there is a mono signal at the rear & ideal for this application but I wanted to verify this before I go tapping into a set of wires. Can anyone suggest the best method for installing a single channel mono amp so I can add an additional 10" sub?

Thanks!

 

[Jay Nice]

I guess my question at this point is... could I run speaker wiring in parallel from the factory sub location mentioned in the post below? I've also attached the wiring diagram. It's a simple install but I would like to hear what others have done with positive results.

"Remove rear passenger side paneling. Unbundle the wiring mess at the amp. Check out wiring diagram posted above for the sub speaker wires or just cut the wires near the sub. These will be your speaker level inputs for the sub amp. Make sure your sub amp has speaker level inputs or you may need to buy a line output converter (loc). I first used a cheapo Pac loc but the line level output was really weak. You may have to do a little trial and error with the amp gain or get a powered loc (Audio Control) and see if you can get enough volume"
http://www.toyota-4runner.org/5th-g...kers-but-keeping-head-unit-2.html#post2310234

 

[a t l a s]

I don't know much about the JBL system, but at the speaker (line) level it works all the same. I personally would first try to find out if the door speakers have a crossover blocking out low frequencies. I would imagine they don't though, because it would be a lot of work for the little stock 8" to fill the truck with bass without the help of the door speakers.

If that is the case, you can install an LOC tapped from the front or rear door speakers (do this from behind the radio), then run the signal down to your amp. This would be a full range signal.

I would not keep the stock subwoofer connected because it will have a negative effect on the low frequencies produced by your new woofer. Additionally, the stock subwoofer probably is on a crossover so you won't really be able to use it for the midrange like you hoped.

Most monoblock amps will have a low pass filter knob where you can control the highest frequency, so you can set this higher (e.g 250Hz) to have the new subwoofer help out a bit in the lower midrange. I personally set my LPF to about 20Hz above the lowest frequency of the door speakers, just enough overlap to remove any noticeable step-off, and this tends to produce the best sound quality in my opinion.

 

[Jay Nice]

I don't know much about the JBL system, but at the speaker (line) level it works all the same. I personally would first try to find out if the door speakers have a crossover blocking out low frequencies. I would imagine they don't though, because it would be a lot of work for the little stock 8" to fill the truck with bass without the help of the door speakers.

Agreed. The door speakers do provide the lower end to help out the 8" stock sub.

If that is the case, you can install an LOC tapped from the front or rear door speakers (do this from behind the radio), then run the signal down to your amp. This would be a full range signal.

My only concern with this is that I only require a mono signal for a single channel amp.

I would not keep the stock subwoofer connected because it will have a negative effect on the low frequencies produced by your new woofer. Additionally, the stock subwoofer probably is on a crossover so you won't really be able to use it for the midrange like you hoped.

Good point! I was considering removing the stock sub/box & selling it & replacing it with the 10" sub in the same location & keeping the stock amp where it is from factory.

Most monoblock amps will have a low pass filter knob where you can control the highest frequency, so you can set this higher (e.g 250Hz) to have the new subwoofer help out a bit in the lower midrange. I personally set my LPF to about 20Hz above the lowest frequency of the door speakers, just enough overlap to remove any noticeable step-off, and this tends to produce the best sound quality in my opinion.

I appreciate the settings. A lot of this will also depend on the cubic ft of the box & sub. I'm not looking for anything crazy either. The factory system could use a bit more on the low range, that's all I'm looking for.

 

[a t l a s]

My only concern with this is that I only require a mono signal for a single channel amp.

Most if not all monoblock amps will have a stereo input (red and white RCA aka right/left). The amp itself is what mixes the two for a mono signal to the sub.

 

[Jay Nice]

Most if not all monoblock amps will have a stereo input (red and white RCA aka right/left). The amp itself is what mixes the two for a mono signal to the sub.

I'm an idiot! I was thinking one wire per input for some reason lol

Thanks for steering me in the right direction. I appreciate the help!

 

[4Rums]

I would not keep the stock subwoofer connected because it will have a negative effect on the low frequencies produced by your new woofer. Additionally, the stock subwoofer probably is on a crossover so you won't really be able to use it for the midrange like you hoped.

+1. The crossover for the subwoofer is done at the JBL amp so you have no control over the crossover frequency. I'd tap the rear doors that have a full range signal. The front door and dash are also crossed-over at the amp. Also, I'd probably disconnect the factory sub as well.

 

[Jay Nice]

+1. The crossover for the subwoofer is done at the JBL amp so you have no control over the crossover frequency. I'd tap the rear doors that have a full range signal. The front door and dash are also crossed-over at the amp. Also, I'd probably disconnect the factory sub as well.

I appreciate your insight as well, thanks! I'll just follow the written how to in the write up section & tap into plug #G5 (rear), simple enough. I'll try both methods as well, with & without stock 8" to see how the combo compares understanding that one may cancel the others frequency. Some of these combos do work, depending on bass freq & from what I'm reading, smaller speakers.

Sometimes I make things a bit more difficult than they really are with overthinking lol :frog:

 

[4Rums]

I appreciate your insight as well, thanks! I'll just follow the written how to in the write up section & tap into plug #G5 (rear), simple enough. I'll try both methods as well, with & without stock 8" to see how the combo compares.

Sometimes I make things a bit more difficult than they really are with overthinking lol :frog:

If you are referring to the G5 plug referenced in this post, you may have to go back to the drawing board - the JBL system doesn't have speaker level wires accessible from behind the head unit. The speaker level wires come out of the JBL amp that is next to the Subwoofer.

 

[tigger]

Keep in mind that these systems have a pretty significant bass drop off as you increase the volume. You will need some type of bass enhancer to overcome this issue if you want to maintain a consistent bass note.

 

[4Rums]

Keep in mind that these systems have a pretty significant bass drop off as you increase the volume. You will need some type of bass enhancer to overcome this issue if you want to maintain a consistent bass note.

That's another drawback of the JBL system. The factory tuning sucks. Seems like they overcompensate the bass and treble so that they get a semblance of sound with crappy factory speakers, so when you replace those, the base EQ curve is screwed up and nowhere linear/flat. I first replaced the door/dash speakers trying to get a better sound and wasn't happy. The bass was muddy and the treble fatiguing. A few months ago I replaced the head unit (wanted Android Auto) and after trying to EQ the crap out of it, I'm still not happy. I wish I had heeded the "pay once/cry one" advice and replaced the damned thing at once. After the holidays, I'm going to get a 5-channel amp (or a 4 channel + a mono), rewire the doors, and rip the whole JBL thing out and get a quality sub in the original location.

 

[Jay Nice]

If you are referring to the G5 plug referenced in this post, you may have to go back to the drawing board - the JBL system doesn't have speaker level wires accessible from behind the head unit. The speaker level wires come out of the JBL amp that is next to the Subwoofer.

That's the one I was referring to, thanks for pointing that out.

Keep in mind that these systems have a pretty significant bass drop off as you increase the volume. You will need some type of bass enhancer to overcome this issue if you want to maintain a consistent bass note.

Already have one. I was worried about this to begin with.

That's another drawback of the JBL system. The factory tuning sucks. Seems like they overcompensate the bass and treble so that they get a semblance of sound with crappy factory speakers, so when you replace those, the base EQ curve is screwed up and nowhere linear. I first replaced the door/dash speakers trying to get a better sound and wasn't happy. The bass was muddy and the treble fatiguing. A few months ago I replaced the head unit (wanted Android Auto) and after trying to EQ the crap out of it, I'm still not happy. I wish I had heeded the "pay once/cry one" advice and replaced the damned thing at once. After the holidays, I'm going to get a 5-channel amp (or a 4 channel + a mono), rewire the doors, and rip the whole JBL thing out and get a quality sub in the original location.

& the plot thickens. I guess we'll see what happens after adding the additional sub with or without the 8". I don't see many people on the forum attempting to do this install according to the search results, so I have nothing to go off but to try it myself. I've had the audio components laying around for a while & was going to make use out of it. If it doesn't work out, I'll sell them & use the sale towards upgrading the factory 8" sub with one recommended for the factory system. I forget which one (kicker?) but I've seen multiple posts regarding the upgrade through Crutchfield. Otherwise I'll just leave it be... I appreciate the replies.

 

[4Rums]

I think your best best is to do something similar to what this 4th gen did with his JBL. Our systems are very similar. Doing it that way, you can try running the subs in parallel. If you like them, keep them. If you don't, you can remove the OEM and see if you get the frequencies you need with the standalone one.

 

[jay35]

Apologies for bumping an old thread. This seems to be the most relevant one for my questions.

It sounds like the best/easiest way to get an additional mono sub & amp installed in a 5th Gen would be to:

• Plan to tap into rear speakers for full-range of frequencies, rather than tapping into the factory sub feed which is likely to already be passed at some frequency specific to the capability of the cheap factory woofer rather than an aftermarket unit with greater capability.
• Start with a trim level that includes a sound package with the subwoofer in the cargo area side panel so the wiring is there. But that may not be necessary since there is power running near there regardless due to the power outlets nearby.
• But you'd probably want to run your own heavier gauge wiring from the battery anyway so maybe it makes no difference whether the factory sub is there or not since you're still going to have to run a power wire from the engine bay all the way back to wherever you mount the sub and you probably don't want to tap the signal to the factory sub anyway.

Is there a particular LOC (Line Out Convertor) recommended for tapping the signal from the rear speakers in a Toyota?

 

[GatorFL]

OEM Audio Plus has a plug and play subwoofer available for the JBL system.

 

[david05111]

A brief bit of input here.

I had a JL XD600-1 and JL 12W6 in a sealed box installed almost two weeks ago.

The shop that did the install tapped the factory sub line. I don't notice a loss of range of frequencies. They still come through to the sub, though some the higher frequencies don't hit terribly hard (not unexpected).

It hits really hard on the lows though, and I know the factory sub can't touch some of those frequencies. I'm not sure there's much to be gained by tapping a standard speaker for the "full range"

 

[jay35]

Interesting. Good to know!
[MENTION=52779]GatorFL[/MENTION] - Already got a sub and amp to use from a previous vehicle build. Just planning out where to tap and run wiring.