2ohm factory speakers? 4 ohm a/f deck?

[celicatalk]

Hi everyone,

Have two concerns:

I am finally gonna invest in a new head unit for my GTS, upgrading from my premium toyota deck.

I know there is a lot of discussion about bypassing the stock 6 channel amp. Is it safe to run the front speakers in series since after market decks are only 4 channels? Also, are there any issues or concerns with running the premium toyota speakers at 4 ohms on the a/f deck, since they are 2ohm speakers (i assume the 6 channel factory amp is a 2 ohm amp), as the factory speakers all have 2 ohm written on them.

Also, has anyone tried installing an aftermarket deck and not bypass the built in amp of the premium package? If so, did you get any noise or experience any problems?

Thanks!!!!

[kkrkeith7]

i believe the speakers are 4 ohm?

[celwin]

wiring the front GTS speakers in series is fine. That's my current setup for the past 8 months. Absolutely no problems with doing that. The speakers are indeed 4 ohm speakers not 2

[celicatalk]

Well, mine have it printed right on them saying 2 Ohm. What is going on? I have a 2002 GTS.

[00CericaRuss]

well, if you run the fronts in parallel, you get 3ohms, if you run them in series, you get 6ohms

i had em in series before installing my amp, and the fronts were quiet.

[zcs626]

normally all stock speakers are 8 ohm.

[celicatalk]

So is there any concensus on what Ohm rating the stock speakers are? I would think all GTS speakers would be the same? I know mine says 2 Ohm on them.

If they truely are 2 Ohm, then should I:

A. Bypass factory amp, Wire the front in series
B. Bypass factory Wire the front in parallel
C. Feed factory amp from aftermarket deck

Thanks guys!

[00CericaRuss]

well.. i never actually measured the impedance from the speakers themselves, just in the passenger side kickpanel..
the low was 4 ohms and the the highs were 2 ohms (i think)

i choose either b or c
b - i don't think running a deck at 3ohms will kill it
c - they had it working well, and it sounded decent, it's just that the deck sucks ass stock

[00CericaRuss]

or.. of course, you can go for a, and just turn the fader towards the front

[celicatalk]

00CericaRuss,

Thanks for writing back! If I decided to feed my factory amp from a new aftermarket deck, is there anything negative in doing so? I know it feeding an amplified signal into another amplifier can amplify noise, but if my a/f deck has a clean output, I would think it would be better than the original factory deck.

Thanks,

Jon

[Deftech]

The problem you will most likely encounter is that your factory deck just sent a signal, no power, probably no more than 1-3w You will now try and send a 40w signal to an amps inputs. What you will probably experience is alot of clipping and distortion. I may be wrong but that is typically what would happen.

If you have a home stereo with phono inputs try this it is pretty similar. Plug a different source such as your cd player into these inputs. You will get really awful sound. This is becouse Record players provide a lower level signal to the reciever than a normal output. Therefore these inputs are amped prior to feeding to the amps for the speakers.

[celicatalk]

Hi Deftech,

How could I find out what the wattage/amplitude of the output of the factory permium deck is?

Thanks!

[Deftech]

You could try contacting Fujitsu Ten and find out what they say. Or you could locate a wiring diagram, Hook up your stock deck and use a digital multi-meter to measure it.

Would take alot of work.

If I remember right, the stock amp is only like 200 watts. And that is on 6 channels. So depending on your new deck, You might be better off using it's amp. My Alpine is 60 x 4 so I am at 240 with the aftermarket deck and on 4 channels. rather than somewhere near 30.

Another option would be to try converting a set of RCA Cables to the inputs on the amp if you can get a wiring diagram. Then you could use the Pre-amp outputs on your aftermarket deck.

[celicatalk]

Hmmm,

Do you think I could take the new a/f deck's RCA outputs and wire them to the factory lines that feed the factory amp? Would the signal be strong enough?

Thanks!

[Deftech]

That's what I said. well at the end anyway. You still need a wiring diagram though. What is the rated output of your aftermarket head unit?

[celicatalk]

50 watts MOSFET / 22 RMS

[Deftech]

That should be as capable if not more than the factory amp. I'm not entirly sure what it's power rating is but I believe it was 200 for 6 channels. Thats Peak power not RMS.so roughly 33.3333333 watts per channel peak, that is if they are all created equal.

RCA cables are actually a set of Positive and negative leads. This inner section (Male) is the positive and the outer section is thenegative. If you took a set of RCA Cables and split them into the 4 wires, you would have right and left positive and negative leads at a line level signal.

Now if the wiring for the factory amp uses line level feeds you could then attach the leads created from the RCA's to the factory amp's input.

Do NOT try this w/o checking wiring diagrams, voltage and wattage. I really don't want someone telling me I blew up there amp or head unit. And make sure all connections are done properly to precent shorting something out.

[S|Lv3rBu||et]

Guys, I think what is happening here is that the Six Channel Amp is powering the rears with two channles, the mids and tweeters with two channels, and the midbass's with two other channels.... so its really by-amping the front speakers. So, if they are two ohm speakers, and you wire them in series, you will get a 4 ohm load.... just what new head units like. I'd give that a try.
If they are not a two ohm load each -or- they are two ohms and you wire them in parallel, it could get nasty for the new headunit....

[celicatalk]

Interesting Silverbullet....

So running 2 ohm speakers in series will make them 4ohm?

Thanks!

[S|Lv3rBu||et]

2 + 2 = 4
:thumbup:

[Deftech]

I have had my fronts wired in series for over a year now and have had 0 problems. Just forget about your factory amp and use the one in your head unit. If it isn't giving you the sound you want then you either need new speakers and/or a seperate amp.

[celicatalk]

Deftech,

Do you have an outline of what you did? Color codes of the wires from the amp etc? Where you cut the wires/ran new wires?

Thanks!!!!!

[Deftech]

There is a write up in the install section on this site. I think it is pretty acurate, Haven't read it in detail. I also kinda outlined it in a post by WillyK in this forum. Too tired to search for it, Will try to post later.

Read those and feel free to ask any ?'s I read here every couple of days.

[celicatalk]

Deftech, I read your post you noted. Good detail! What kind of after market deck do you have? Also, are the front speakers more quite than the rears since they are in series?

Thanks!!!!!

[S|Lv3rBu||et]

No, the fronts (given they have the same efficiencey, going from a 2 ohm load to a 4 ohm by wireing in series does drop about 3dBs) should be ok, otherwise, you can use your fade control to even em up.

[celicatalk]

Silverbullet,

How did you calculate 3db? Thanks for the great info!!!!

[Deftech]

I have an alpine 78XX head unit, Can't remember the model number. It's 60 x 4 and no you can't really tell if the fronts are quiter.

It's a nice deck I like it so far. Never skips and have had zero problems w/ it.

[S|Lv3rBu||et]

The 3 dB I stated is sort of a rule of thumb when it comes to output vs impedance. anytime you wire two equal loads in parallel, you add 3 db, anytime you wire them in series, you subtract 3 db. So, say you had two 8 ohm speakers, each with a 90 db efficiency (1w/1m). If you wired them in series (total 16 ohm load), the collective output of the two speakers, given the same 1w input would be 87 dbs, if you took the same speakers and wired them in parallel (total 4 ohm load), the collective output would be 93db. This all goes back to the post about wireing subs in series/parallel. When the collective impedance goes down the collective output goes up.

[celicatalk]

Thanks for the details Silverbullet and Deftech! One last big question... how do you cross the stock speakers when running them in series on an aftermarket deck? Do you just run the full range signal to all of them. I know the tweater has a filter right near it, but the mid and woofer look to be crossed at the old factory amp? Any ideas? Deftech, what did you do?

Thanks!

[S|Lv3rBu||et]

Yeah, the factory amp probably has crossovers for them.
Well, unless you plan on bi-amping them, (meaning you plan on sticking with just the headunit for a while) I would build some simple crossovers for them. Just a little capacitor/inductor circuit.
Wouldnt be too costly and you could get all the pars at
www.partsexpress.com

i think they even have a guide there to tell you what values you'll need. But if they dont, PM me and I will figure it out for you.

[Deftech]

There is a transistor on the back of the tweeter that is basically a cross for the mids. I have the head unit crossed at 120 db so nothing under 120 goes into any of the stock speakers. I didn't change anything else and it sounds fine. Probably not the best way to do it, but not doing much damage with a 6.5 powered at only 60w. Now if I were sending 100 or 120+ into them a crossover would be real important for sound quality and clearity.

They will be ok, If you are real concerned you can buy passive crossovers pretty cheap. or if you have subs already and a cross in your head unit, just take it out from there.

[celicatalk]

Deftech,

Do you mean 120 Hz? If so, do you send the woofers the full signal above 120 HZ?

Thank you so much!!!!!

[Deftech]

Yeah sorry Hz, my bad. Too Many abbreviations some times.

I also have 2 JL subs running off a Alpine amp(Crossed at 140Hz), so I don't need the lows in the doors. I would suggest hooking it up as described previously w/o crossovers, Listen to it if it sounds good for now leave it. If not look into upgrading w/ subs and an amp. Even one sub and a small amp could be better, Then limit the signal to your stock speakers.

If you really want crossovers and components, buy some aftermarkets like Boston Pros, JL, or MB Quarts

[celicatalk]

Deftech,

I have a sub and amp already, using high inputs from the rear channels of the stock deck. My new deck has RCA outputs for the sub. I put 200Hz bass blockers (-6dB per octive) on my woofers and rears already too. I don't like distortion when playing really bassy music, and my sub is crossed at 300 or so. It's a bass reflex 10" sub.

I will go ahead and wire it in series when my deck comes in and let you guys know how it turns out.

Thanks for all the help!!!!!!