Can I keep small tweeters connected with new head unit?

[thomaspuzio]

I have a 2003 Toyota 4Runner Limited with the JBL 10 speaker system and in dash 6-disc changer (no navigation unit).

I decided to replace the head unit with a JVC KW-XR810. I had Best Buy install it (got a gift card for Christmas, thought i'd give 'em a try, they did OK).

After the install I decided to upgrade the subwoofer using the same method discussed here:
http://www.toyota-4runner.org/4th-gen-t4rs/62400-replaced-jbl-sub-added-amp-install-pics-info.html

I went to a "real" audio installer this time. The guy took a look and suggested two options:

1. replace the sub and add the sub amp
2. replace the original JBL amp using a 5 channel amp like the JL Audio XD700/5
JL Audio XD700/5 Amplifiers - Car Audio Amps & Amplifiers

He suggested this option because it would provide better customization of sound quality as well as eliminate the problem I have had with the sporadic cutting out of the audio signal which is likely due to the amp freezing up.

He said that if I used the new amp he wouldn't connect the small tweeters in the front doors or rear lift gate. He explained that the 5 channels would power two front door speakers (2 channels R/L), two rear door speakers (2 channels R/L), and the sub (1 channel). He said that if he connected the small tweeters with the door speakers it would limit the bigger door speakers.

Right now I can hear music coming out of those speakers so obviously the Best Buy guy connected them somehow.

I have lots of questions:

• Does the JBL amp have discreet channels for those small tweeters or are they ganged up with the door speakers?
• Whats the best choice to use all the speakers I've got?
• Is it simply better to disconnect those small tweeters and just go with the 4 door speakers and one sub?
• Can you connect these small tweeters along with the door speakers without degrading the signal/sound quality/loudness of the door speakers?
• What about the XD600/6 versus the XD700/5, could I connect all my speakers better with the 6-channel amp?
• Is the XD600 powerful enough to drive all these speakers?

I am trying to decide on the route to take and any help is much appreciated

 

[Liq]

So here is the first and most important question, whats your budget?
The guy at the shop was right when he said the 5 channel amp would give you better control over your system, but it comes at a cost. Both of those amps are around $600 alone, then install on top of that. Replacing the sub and adding smaller sub amp would be well under that.

The order of replacing components from biggest difference to least is debatable and dependent on what your trying to achieve, but having worked in the industry for a while here is my preferred order.

1. Head unit (due to functionality gain)
2. door speakers for sound quality and power handling
3. subwoofer & sub amp
4. amping door speakers

I don't have the JBL system personally but I checked the schematic, and for the door speakers and they are just like the non JBL setup, the tweeters in the doors are in parallel with the lower door speakers so they will work no problem. You should not disconnect them if you replace the amp. The JL amp will be able to handle it fine, its no different than if there were only 1 speaker.

If you were to replace the amp, no matter which one you choose, you would loose the speakers in the D pillars (the far back) and the center channel. They are not stereo and would not have added anything beneficial to your system. Your new head unit can not take advantage of them.

If it were my choice, I would upgrade all the door speakers first before getting a multi channel amp. A component set for the front, and some co-axials for the rear. Then you could get the JL 700/5 and replace the stock JBL amp with that, adding a new sub. amping factory speakers usually results in terrible sound quality because the speakers weren't designed to handle more power than the stock amplifier can put out.

 

[thomaspuzio]

OK so I think I'm good with keeping my JBL amp and just adding a sub amp and replacing the sub to enhance the low end in the system. The JBL system sounds pretty darn good to my ears as is, but I do have a slight issue with the semi-weak bass and the fact that the door speakers in the rear passenger doors aren't as loud as the front passenger doors.

If I use the fader to push the sound stage toward the rear, the overall volume output seems to diminish (and not because I'm sitting farther from the sweet spot). It's as if the rear passenger door speakers aren't capable of pumping out the same level as the front door speakers. Would this be a fault of the speakers or the amp or what?

So if i decided to replace the 4 door speakers...
1. What's a good option for say under $200
2. Would I need to bother with the small door tweeters or since they're so small it doesn't matter (in terms of replacing them)

As to replacing the JBL amp and losing the rear lift hatch tweeters...
Could you explain why I would lose those? I'm not sure I understand that. Couldn't you just connect them in parallel with the rear passenger door speakers, the same way the front door speakers are paired with the front door small tweeters?
I understand the center front speaker is a mono speaker and was used for the surround mode in the JBL head unit, so I get that I would lose that with a new head unit that doesn't support surround sound. However, since there are two tweeters in the back, one right side and one left side, why can't they act the same as the small tweeters up front? Also, if they are working right now with the stock JBL amp, how are they hooked up if not in parallel with the rear door speakers?

Thanks for your response, I like learning about this stuff

 

[Liq]

So the JBL amp is a 8 channel amp. the first 2 channels go to the front door speakers and tweeters (L+R), 1 channel for the center speaker (mono), 2 channels for the back door speakers (L+R), 1 channel for the rear pillar speakers (mono), and 2 channels for the sub (dual voice coil).

Chances are any sub you replace the stock one with is going to be single voice coil, if its a dual voice coil you would wire them in parallel or series to give you the best load for the sub amp, hence creating a single channel or mono speaker.

Your right, the rear pillar speakers could be wired in parallel or series with the rear door speakers. However, when you put speakers in parallel you effectively lower their impedance (resistance of the voice coils). when you put them in series you add the values. Higher impedance, less power, less volume. lower impedance means more power, higher volume. Without getting into all sorts of circuit theory, the JBL amp cant handle it. Any load you are likely to generate by wiring multiple sets of speakers together will be more than that amp was designed to handle. Most aftermarket full range speakers are going to be of the 2 or 4 ohm variety, perfect for new headunits and amplifiers.

Those speakers in the back do have lower frequencies filtered from them but I dont believe they are tweeters, they are more a mid and high range speaker. same with the center channel. You will notice a great difference replacing the back door speakers with a 2 way coaxial speaker and disconnecting the rear pillar ones.

here is the schematic so you can see what im talking about:

If you were to replace your door speakers I would recommend getting a component set and replacing the tweeters with them. there is no comparison between a good matched component set and a mix match of after market and stock equipment. speakers like to be in matched pairs with good crossovers, which a component set will do for you. the rear doors i would recommend a 2 way coaxial speaker, these have tweeters sitting above the woofer all in on nice package. If you want to step it up a notch you can also install a component set in the back doors. 4th gens have perfect flush mount locations.

Ill do a separate thread tonight with my setup in it so you can see what ive done. deciding on speakers is a matter of preference. some will argue up and down why one brand is better than another. best bet is to so to the shop and listen to their sound board, listen specifically to the highs and tweeters. their speakers will always sound better in the sound board because they are in nice enclosed boxes and evenly spaced. once you get any speaker into your car it will take on different characteristics. mounting things in doors tends to change the bass response in most speakers. just find something that you can afford and that sounds good to YOU!

 

[thomaspuzio]

I feel like Joey on Blossom, "Whoa!"

First, thanks for taking the time to post such an informative reply. I feel like I'm being schooled by a master.

I think you've convinced me that since I'm going to have my car stereo worked on and a sub and sub amp installed, it seems like a no brainer to replace the door speakers too while i'm at it.

I like your component up front, coaxial in the back (and leaving rear pillar's unplugged).

Do you have that diagram in higher resolution?

 

[Liq]

I actually just got the whole manual from here:

2006 Toyota 4 Runner Wiring Diagram | Free eBook Download
pages 345 and 346

 

[thomaspuzio]

So I'm thinking of buying these:

For front components: Polk Audio MM6501
Polk Audio MM6501 6-3/4" component speaker system — also fits 6-1/2" openings at Crutchfield Signature

For the rears I would get the matching coaxials
Polk Audio MM651
Polk Audio MM651 6-3/4" 2-way speakers at Crutchfield Signature

Crutchfield fit guide says they won't fit, I can't access Polk's fit guide so I can't confirm that. I'm guessing the problem is that i'd need to make a custom mounting ring adapter or something for each location. I don't see the depth being a problem because they are listed at just under 3" deep and I supposedly have 4" available.

Any ideas why Crutchfield says they won't fit?

Any experience with those speakers?

I stumbled on those because they are one step down from the top model Polk makes. They happen to be marine certified which likely bumps the price a little, but i'm more interested in their performance over the model below them.