4-Channel amps

[1sty]

I replaced the fronts already and have the wire harnesses. I knew the front left was yellow & grey. I saw that on the HU, tho the front right wires were not there. But, there was another set of 2 wires taped together right next to the front left so I took the chance that was the front right wires. They were. Luckily, Mazda taped + & - of each speaker together, and separated fronts from rears on the harness, makes it a little easier. None of the wire colors were like a Mazda 3 ( I think it was the 3) that I had.

You probably have the right + and - signal of the deck flip/flopped. This would not cause an extreamly noticable issue with the stereo amp channels but it would essentialy kill the subwoofers bridged channels. Swap the right channels + and - of the amplifiers intput. Swapping the amps output is not possible to the bridging of channels.

 

[1sty]

Arggh. That was a mission to get that thing wired up. Is the only benefit fading the sub?

yep

 

[Kid Red]

IF you wired it normaly then the result would be 2 identical mono channels. In your case, you want a single mono channel and 2 stereo channels so wire the inputs as you would normally.

How would that be wired then? I can't figure it out unless I have to re-wire the inputs because I have them normal right now and it doesn't work for 3 & 4 being mono.

 

[chuyler1]

What 1sty is saying is that the inputs on the alpine harness are independent of the outputs. Wire the alpine harness as if you wanted a 4-ch setup, no if-ands-or-buts. Then wire the output channels in the suggested 3-way configuration by bridging the rear output channels to the subwoofer.






<pre>
L= left
R= right
F= front
B= back (or rear)
S= speaker
SS= subwoofer
Input harness (2 channels from head unit)
(not sure if this works when bridging)
L+ L- R+ R-
/ \ / \ / \ / \
FL+ BL+ FL- BL- FR+ BR+ FR- BR-

Input harness (4 channels from head unit)
FL+ FL- FR+ FR- BL+ BL- BR+ BR-
| | | | | | | |
FL+ FL- FR+ FR- BL+ BL- BR+ BR-

Output speaker terminals
FL+ FL- FR+ FR- BL+ BL- BR+ BR-
| | | | \ /
LS+ LS- RS+ RS- SS+ SS-
</pre>
</pre>

 

[1sty]

How would that be wired then? I can't figure it out unless I have to re-wire the inputs because I have them normal right now and it doesn't work for 3 & 4 being mono.

1000:1, it doesn't work becuase you have the - and + of the decks right channel output mixed up. Just swapped them around at the headunit connection.


Again, if one channel is out of phase (+ and - reveresed) the result for a stereo channel will be a slight loss of base and generaly less then desired SQ. If they are swapped for a mono channel, you will effectly kill the output signal, which is how you describe the subwoofer.

 

[Kid Red]

chuyler1- The Alpine's 4 channel wire harness is wired up. All for channels input into the Alpine are being used by the amp. I see what you are saying. When I get the AuxMod and I have to take everything apart, I'll add the rear HU oututs- inputs to the amp.

1sty- If the input was out of phase, would the fronts sound perfect? I understand where you're coming from, but unbridged everything sounds perfect- so I don't understand how something could be out of phase before bridging. As is, using 3 channels, I have tons of bass and excellent SQ and SPL has to be high. Trying to make 3 & 4 mono is where the problem presents itself.

For ships and giggles I'll switch them tho.

 

[1sty]

chuyler1- The Alpine's 4 channel wire harness is wired up. All for channels input into the Alpine are being used by the amp. I see what you are saying. When I get the AuxMod and I have to take everything apart, I'll add the rear HU oututs- inputs to the amp.

1sty- If the input was out of phase, would the fronts sound perfect? I understand where you're coming from, but unbridged everything sounds perfect- so I don't understand how something could be out of phase before bridging. As is, using 3 channels, I have tons of bass and excellent SQ and SPL has to be high. Trying to make 3 & 4 mono is where the problem presents itself.

For ships and giggles I'll switch them tho.

Perfect is a relaitve term. Right now you are comparing to the factory system so you have "perfect" sound, even with a driver out of phase. Swap that one speaker that's out of phase back in phase, and you have yourself a new "perfect".

An out of phase speakers like mids and tweeters don't cause really anything but some imaging issues, which you probably aren't listening for and wouldn't notice unless you were in a competition level car. Other then that its just going to take away some midbass. The midbass difference, which can be VERY slight, will not be noticable by many people, especialy amoung 3 others speakers that are in phase.

Also, something to consider is that it is VERY common that compeditors will purposely put a speaker out of phase because the acoustical wave itself is out of phase at the drivers seat although in phase electricly. Good stuff (thumb)

 

[Kid Red]

1sty- I'll take your word for and give it a shot. I'll try wiring just the sub bridged first. THen once I have 3 & 4 feeding the sub in mono, I'll wire up the fronts.

 

[1sty]

I would go the other way. swap the +,- of the front right output of the deck and see what happens to the front speakers. without the sub involved.

Or, and why and am I only thinking of this now, with your system as is:
1. Fade allt eh way to the front to cut out the rear speakers totaly
2. Balace to the right and left. If you are in phase, you will hear noticalby more midbass and low bass when you are centered. If you do not hear more base as you balance toward the center, then the speakers are out of phase.

 

[Kid Red]

1sty- K, I did that. It's weird. When it's to one side, the bass hits, when it's centered and I sit in the center of the car, I feel the bass, and can hear it, but it's not what I would expect from both speakers. It's like the bass is there but it's not hitting me hard from both sides like I would expect. Sounds like it's crossed then huh? I'll switch them in a little bit, gotta try and get some work done.

Is it possible that my inputs are correct, but that one of the speakers themselves is out of phase? I was always suspicious that after replacing the door speakers that one was out of phase. I just chalked it up to 6x8s with no amp. Is there a way I can test the inputs using the sub? THen once I know the inputs are correct, I'll have to open the door and change the speaker connection, as it's just one of the speakers and as long as they are both the same they would be in phase. Correct?

 

[1sty]

Is it possible that my inputs are correct, but that one of the speakers themselves is out of phase? I was always suspicious that after replacing the door speakers that one was out of phase. I just chalked it up to 6x8s with no amp. Is there a way I can test the inputs using the sub? THen once I know the inputs are correct, I'll have to open the door and change the speaker connection, as it's just one of the speakers and as long as they are both the same they would be in phase. Correct?

That won't effect the subwoofer channels of the amp though.

To check speaker phase:
1. Get a AA battery or similar. Just something small
2. Disconnect the amps outputs to the speaker. TAP!!! the batteries +/- to the speakers +/- wires. If the speaker fires out, its in phase. If the speaker pulls in, its out of phase.

This is phase in relation to the wiring from the amp to the speakers. If one speaker is out of phase at this point and the input wiring is also swapped then that speaker will end up being back in phase. Or if the left speaker is out of phase but the right speaker is in phase but the right input to the amp is wrong then both speakers end up at 180 Degrees out of phase but since they are both out of phase, they are technicly in phase with one another, but not with the rears.

 

[Kid Red]

The speakers are in the doors so I won't be able to tell which way they fire

What would be the next option? Just one speaker at a time or something?

 

[chuyler1]

Just shine a flash light through the grill, you should be able to get a glimpse of it while someone else taps the battery on the wires.

 

[Kid Red]

K, I'll give it a try on both fronts and see what happens.

 

[Kid Red]

That was it!! Thanks guys! I did one speaker are a time and I could tell right away the difference. These Polks have some bass to them, wow. Then I was able to bridge channels 3&4 and the sub was hitting some lows. All is good, ready for the ID8 to arrive.

As for tweaking, what's the best way to get a nice flat sound? I'm looking for even sub volume. I like my bass, but I listen to more then just hip hop, and don't want too much bass when there shouldn't be. What's the best method of achieving a well balanced sound?

 

[chuyler1]

It usually just takes alot of listening and playing around with the crossover points and gains to get things dialed in right.

Getting the sub at the right level is tricky and that's why I recommend using all four channels on the head unit so you can fade between front and rear quickly.

With the crossovers, you'll probably end up with them set between 70-100Hz. However, that's a pretty big range believe it or not. Experiment with the point for each one independently (it's ok if they overlap a little) to see what your fronts are capable of handling cleanly and what the sub can play without localizing the bass in the rear of the vehicle.

Don't bother with bass boost (if the amp has one)...the feature is a relic and is not going to help you get a smooth sound. Keep the head unit bass/mid/treble settings flat for your initial tests.

 

[Kid Red]

I got the ID8 and wanted to hear it so I fashioned a face plate and put it inside my old 10" box that was pretty small o begin with. It definitely has a lower end response then the 10" sub (Precision Power). My question is this- the ID8 dims my lights pretty noticeably when the 10" sub didn't. I'd rather not have my lights dim, should I return the ID8 D2 for the D4? Why does the 8" dim the lights when the 10" doesn't? Does the 10" have a higher sensitivity?

This is going to be a difficult job trying to FG an enclosure there. A difficult time indeed.

 

[1sty]

What was model number of the PPI sub? Or more importantly, what is the voice coil impedance.

Also, did the onld sub not dim the lights when you had the right channel wired backwards or after that?

I would pop the 10" back in there to do a proper comparision. Either way, it is the amp dimming the lights not the sub so either the gain is up higher with the 8" then it was with the 10" or the 8" sub is a lower impedance and is forcing the amp to put out more power. You wired the ID8's voice coils in series right?

 

[Kid Red]

The 10" did not dim the lights, it's a 4 ohm. I have the ID8 D2 wired + & - on the first set from the amp, and the second set wired together. This set up makes the ID8 a 2 ohm set up (from what I read). It sounds good, much lower response than the PPI, but I really don't want lights dimming. The gain for the sub, is slightly lower then half way, the fronts are about 1/4 way and it's a balanced sound. I had to turn it up slightly more for the ID8 than for the PPI 10", I guess because of the ohm difference?

So, I need to return the ID8 anyways, because during shipping the rubber surround has like 5 small impressions. Since the speaker will more then likely be visible after installation, I don't want any impurities in it's appearance. Given that, I can just exchange it for the D4 version if that will keep my lights normal.

 

[chuyler1]

You want the D2 version. Wire AMP+ to VC1+. Wire VC1- to VC2+. Wire VC2- to AMP-. This will give you a 4 ohm total load which is identical to the PPI 10. It sounds like you have the VCs wired in parallel now which is giving you a 1ohm load. This WILL cause your lights to dim and it will also cause the amp to overheat and eventually fail.

Here's a diagram for how you should wire the voice coils...

Here's the wiring tutorial for DVC subs...
http://mobile.jlaudio.com/support_pages.php?page_id=161

Also, the ID8 surround is rubber right? Give it a day or so and see if the impressions fade away.