mikemann

you know, to me...it's not that the rears aren't loud...it's just the comparison to the fronts is night and day. If you fade all the way to the rear and turn up to about 30 volume...the rears are decent...but you fade that to the center or to the front and it's tremendously loud.

SRT4Erik...you're the one that I think that is throwing us all off. I would have guessed it was just the fact that these are smaller (maybe worse since no tweeter/component) than the front and sit so low in the rear that is the reason.

I would have thought for sure, having pgrade/bigger/better speakers would have made the difference.

Can't wait to hear what is found out here.....

BigBHaller

Ok, so I replaced my system with a AVIC-Z2 and the rears are just as low as with the base stock radio. I'm fairly sure that these aren't powered by any amplifiers (other than the head units). So this must mean that the rear speakers just plain... suck.

mikemann

oh man that is confusing! So Erik has new speakers and stock head unit...low rears.

You have a new head unit and stock speakers...low rears.

So does that make it wiring?

-Mike

roXor_boXor

It's the storage under the rear seat absorbing 85% of the rear speaker output.


So I just put the fade on rear 5 and crank it to about 35-40 volume. Good to go. This method also prevents any rattles or squeaks from developing in the future (as far as I'll be able to tell).

Only problem I have then is _____ing from the kids that my music is too loud.

uberspeed

Aren't rears only supposed to provide fill? Highs are very dependant on location due to frequencies, no? High's are directional from what I have always known. Some folks even only use really good component set up front and leave the rears alone. Bass freq's don't matter where they're located, not directional.
When you say not loud, do you mean they're not providing rear fill? Sound imaging will usually fade a bit toward the front, not the rear, at least when I last had a vehicle tuned for acoustics and had the sound stage set for SQ that's what the shop did and it sounded great, my research confirmed their settings...

mikemann

I would say IMO at the same volume level. Faded all the way to the rear, volume output is about half the db as compared to the front or even.

The more I've messed with it. It's really not horrible. It's just definitely different than other cars I've been in. To me it's more of the fronts way "overpower" the rears. When fully faded to the rear, as soon as you start to fade forward towards center/equal the fronts just take over.

Which is why I why I originally said...I just assumed it was a speaker quality/size/placement thing. But Erik's post (especially since he appears to be a car audio guy from his sig) about aftermarket speakers not being better, it a little disheartening.

-Mike

city-soundzdotcom

It really does sound like a placement and power issue. Since i have heard that the speakers are bigger in the front than the rear makes me ASSUME that there also less powered. It is usually that the rears are bigger and more powered in my experiences. I would say if you want more power all the way around to change out the crap stock speakers and put in some good components or at the least three ways. Take the adapter needed and put in 6.5 in the rear as well as the front. Use a small 4 channel amp to power just your speakers. This will mean all speakers get same power, amps, and are the same speakers. Then test to make sure they are wired correctly which you can do with a 9volt battery (the one with both terminals at top) Below this is how to test polarity of speakers. Then you can tune the amp to what you need with the gain and such to get a better level of sound from front to rear. This sounds like it will be the only option for the problem you guys are having.

How to test polairty of a speaker.

First, if you have all factory wiring then find out what colors is pos and neg. It usually will have a pattern to it like the lighter color of the two is pos and he darker neg but not all the time.

Second, if you have an aftermarket stereo in your car and an adapter harness this will be easier for you as they are wired with generic colors. But you still need to write down which stock colors are pos and neg.

The test:

First get your speakers visible so you can see if they pop out or in when you hold the battery to them.

Next: Now this will be easier for some and harder for others. We will use SPEAKER 1 as our example speaker and its wire colors will be PINK for pos and GREY for neg.

Now that i have located the wire color polarity i will begin the test. Take the speaker out of the car, marking which wire was where (pink on left grey on right). Then take two little pieces of extra speaker wire and some how attach them to the terminals (does not need to be fancy, just good enough for the test.) Then after the wires are attached to the speaker touch the pos terminal to the pos on the 9volt battery. Then while you watch your speaker touch the neg terminal to the neg of the battery and you should see the speaker either pop in or out. Write this down.

Now do the same test to all your speakers. Marking what the factory says are the pos and neg wire colors and then putting it up to the battery to see if it pops out or in. Write the results down and review.

It doesnt matter what way it pops (usually out) as long as all the speakers pop the same way. If they all pop the same way when hooked up to the 9volt then your polairty is correct and you are not loosing sound because of a bad wiring job. If they pop differently then you have wiring issues either from factory or if you have an aftermarket stereo then from whoever hooked it up.

If you have any qustions please feel free to ask.

I am very intrested to see what the results will be, i just wish i had the car so i could figure it out.

City-Soundz.com

Bigfieroman

I think I might know why there is such a difference.

The front speakers are wired in parallel with the tweeters behind the mirrors. This presents the head unit with a 2 ohm load, (the tweeters say 4 ohm, i assume the door speakers are 4 ohm, hence 2 ohm overall) resulting in more wattage. Combined with the speakers size difference, the fronts easily overpower the rears. This makes sense, since replacing the speakers or head unit would not fix the problem. You have to bypass the tweeters completely to solve the issue.

I am installing new speakers pretty soon, (6.5 front and rear) and I am going to just bypass the pillar speakers. I think this will drop the front speakers even with the rears, as well as provide an overall cleaner sound (2 ohm is more susceptible to distortion).

SRT4Erik

It doesn't quite work that way. The capacitor keeps the tweeter from playing the same frequencies as the woofer in a range where a 2 ohm load would make a difference. Its still a 4 ohm nominal system. Besides, impedance changes with frequency, rising a lot at resonance. Lower impedances ask for too much current for an amplifiers output stage (if they are not designed for that low), thats why they can clip, causing distortion at max output.

Anyway, after a quick glance, either the rears have less power from the deck's amp itself, or its the small 24-30 gauge wire going to them ;)

City-soundz, polarity wont affect total output too much in the mid-high range, at least not the level that I am experiencing. THe rears are about 20db lower than the fronts. I can stick my ear in front of a rear speaker and still hear the fronts louder at a 0 fade setting. Its just a crappy deck (amp) and/or crappy, small wiring.

Bigfieroman

Ok, so when replacing the front and rear speakers, should I bypass the tweeters or leave them in the loop? (Polk audio db650, btw) Sorry to be a bit off-topic/threadjack.

mikemann

bigbhaller replaced his deck and still has the same issue. It must be the speaker and the wiring then.

So like Bigfieroman, I'm curious....if you wanted to keep the stock deck, what's the best way to solve within reason?

Get a decent 4 channel amp and replace speakers?

uberspeed

The route I'm taking is Premium OEM headunit, then have a shop do:
sound deadening
good wiring
amp
component set(s)

After that I'll look into a sub enclosure or something for lows.

Bigfieroman

I dunno, according to SRT4erik, the tweeters aren't the problem.

city-soundzdotcom

Yes you will still hear sound coming out of the speakers, its just that if the polarity of the speakers is backwards from the front and underpowered then a volume drop will be noticed. The soundwaves actually will cancel eachother out creating distortion and lower volumes. It may not effect as much as other probelms that the whole speaker system seems to be having but will be a noticeable difference if it is wired wrong.

City-Soundz.com

SRT4Erik

factory wiring and all speakers are in phase. I am installing new front components today (mach5 ml-65 mids, seas 27tffnc/g tweets, custom xo's). I might just run new wires to the rear to see if that helps first.

mikemann

Any more news on this? I'm still interested if anyone has made any significant changes/improvements here....

Safetyguy

I am interested in a reasonable solution as well. Standing by!

SRT4Erik

It looks to be the signal processing within the scion decks. Its not the wiring or the speakers. Best cure is probably to run an amp and/or a better deck.

mikemann

was there any more to this? Has anyone just replaced the speakers and kept the stock head unit, no amp?

Any improvement?

-Mike

Lovinitmaui

I put in new speakers all around with stock deck but still the sound in rear sucks. I had tech guy at Kamakazi Audio look at it after and he claims wiring. Suggests add amp and replace wiring.
Anyone else have any other answers??