I have an Alpine 3527V. It's a 4 channel amp, bridgable, and has tri-mode (or what they call "multimode" )

What I want to know is do I have to have three speakers hooked up in order to use tri-mode?

The way I have it now is bridged to 2 channels running my fronts. I have no rears. I have a Punch 100 running my 12" sub.

I want to add rear speakers to give a little more ambiance, but I don't want to lose any power to my fronts by running the amp in 4 channel mode. Right now, since it's bridged, there's 70w going to each front. If I run my amp 4 channel, then it drops to 25 x 4. I also don't want the rears loud. I just want them there to fill a little, so I won't have them even up to 25w/ea, per se, because the fader would be very biased toward the front anyway.

Now look at the pic and tell me if that will work. I want to run my rears off only one of the two available channels while in tri-mode.
And since I have a 4 channel amp that's the way I'd have to hook it up. This way I keep my 70w to each front while sending only 25w to each rear.

Will this cause problems with the amp? Will it not work this way because there's no current on the other channel and it's bridged at the same time? Or should I just try it and see what happens?

Keep in mind that it's an Alpine amp, it's very old, and if I ruin it, it's just a reason to get a new one. It's done it's time well served.

AJ

 

You dont want to do that. Use your head unit to power the rears instead, or get another amp. The "tri-mode" is usually meant to drive two stereo speakers and one subwoofer bridged. You have a 4-channel stereo system, so you want to keep all those channels seperate. Depending on the amp - there are many ways to wire a system, but the way you describe wont give you the results you want. Use your head unit to power the rears especially if you're talking about such low power like that.

 

Well the channels will still be kept seperate. The LF and LR would still only be getting the L signal, and same with the R.

Using the HU is not an option due to the fact that it all goes through an Alpine 3331 EQ. I would get such a flat sound coming from the rears that it would sound like poo poo IMO.

The third amp is an option except I don't feel like spending the money if I don't need to.

AJ

 

I don't understand your diagram. According to your diagram, it's a 4 channel amp. You're showing 2 sets of terminals on both side. The traditional wiring for "tri mode" is to take a 2 channel amp, run a pair of speakers in stereo, then a 3rd speaker in bridged-mono. I suppose you could series-wire the two rears and run them in bridged-mono, but I see no advantage to doing it that way.

Personally I'd just run the rears off of deck power, but if you're hell bent on amping them, just parallel them with the front speakers. Any amp that's worth it's weight in **** will be 2 ohm stable in a stereo configuration. You'll wind up with close to 2x the power output from the amp (due to 1/2 the impedance) so your front speakers will still get the same power they do now.

 

It IS a 4 channel amp. I said that earlier. The front speakers that I have now are running off the amp with the amp being bridged to 2 channels. So I can't run them parallel off the fronts because that would drop it to a 2 ohm load bridged, and there are very few amps "that's worth it's weight in ****" that will do that.

I'll break it down for you so maybe you can better understand my question.

Here's a 2 channel amp in tri-mode (minus the caps and inductors for simplicity).

 

Now here's what my amp is capable of doing.

 

Here's how I have it now.

 

And here's what I want to do, but I've only posted half the story so maybe you can better see what I want to do.

For the whole story, look at the pic I originally posted and maybe you'll see what I'm talking about.

AJ

 

Ok, now I understand a bit better. I'm not sure that you're going to get any sort of benefit in doing it that way. I'd try running it in 4 channel mode first. You're only going to lose a couple dB in the front speakers. It's not likely that you'd notice.

I don't think that you'd cause any damage in doing it the way you have it pictured, but I'm not sure that it's necessarily going to work real well either. With the stereo portion of the amp being imbalanced due to only having 1 channel driving an unbridged speaker, you may wind up with a signal imbalance in the bridged driver due to the way the amp sums the signal for the mono channel. Then again, maybe not. I've never tried it like that so I'm basically shooting from the hip here.

 

I agree with Jim. I'll just add my perspective on it and see if you agree as well.

You are using your 4 channel amp in a manner that wont technically hurt it, and it wont benefit you in any way either. The reason why is that you have 2 sets of gains on a 4 channel amp ..or you should anyway..but wiring like that will eliminate your ability to balance left/right as well as front/back and gains for the front and rear. All you are doing really is putting more power to the front and less to the rear.

On that note - i see you're only getting 25W to the rear. That is head-unit territory. Your best bet to keep system tunability and longevity, balance, sound quality, is to keep your fronts how you have it now, and hook your head unit to your rears. That way you will still be able to fade back/front, balance left/right, set levels front/back and keep more power where it's needed most - up front. Rears are only for rear fill, and really dont need much power at all at the power levels you are dealing with. Dont be fooled by the apparent overpowering of the front speakers wattage-wise because the rears with 40 watts from a head unit are going to free-up additional load on your amp leaving it to more cleanly power your fronts, as well as keep total flexibility in your system.

Keep your fronts bridged and run the rears off the head unit, run each 4 channels to each 4 speakers normally, or get a new amp. Sure the way you want to do it will work, but you would be taking a step backwards in quality and flexibility in order to play the wattage game. And 25W isn't enough to ante up with If it was 100w then i might reconsider, but you r head unit will surpass the amp in this case if it has decent power.

Whatever you go with - good luck. The way you want to run it is just not the best way. It will work, but it's not your best choice.

 

Wrong. It works great.
Wrong. I still got balance/fade, and my amp only has 2 gains. That's all a 4 channel needs.
That's what I wanted to do. I said that earlier.

I know that. That's what I wanted to do. Keep it up front, and that's what I did. And I can still adjust all those things like I said earlier.
I know. That's why I wanted to do it this way.
Wrong again. I still have as much sound up front PLUS I have rear fill now.

I did.

Why?
How do you figure that since my MAIN GOAL was balance and ambiance? When did I ever say I was going for high wattage? If that was my goal then I wouldn't have a 25x4 amp, and a 50x2 amp.
Wrong again. A H/U's RMS rating is nowhere NEAR that of a HQ amp (like an Alpine ).

Thanks for the stroke of luck??? (if that's what you wanna call it) But you're wrong again. It did work great and it was my best choice because ya know what it cost me??? NOTHING!!!!!!

I love it when a plan comes together.

BTW, thanks Jim for being open-minded about the possibility of it working.

 

AJ - ease up..you misunderstood.
My Quote: You are using your 4 channel amp in a manner that wont technically hurt it, and it wont benefit you in any way either.

I said it WONT hurt it, but it wont benefit you over running rears off head unit as Jim and I had mentioned before. I never said it wouldn't work - reread my post before attacking, please.
You asked if it would work and if it would be safe for your amp. Both answers were yes. I dont see how you have that other flexibility to balance/fade and set gains individually. Maybe thats in your EQ which we can't see or something. Looks to me like you can only set levels for each pair of speakers.

Jim was also correct in saying that the stereo signals will be imbalanced, but you're probably already used to it. If you are using an EQ it might make it sound like a hall effect or reverb-y - which might give you that ambient effect you were looking for.

If you're happy with it, thats all that matters.

 

First... I'm not attacking you, just pointing out that you're wrong. If you take that as "attacking you" then oh well.

How can anything "Looks to me like" when you've never seen my system? Did you go to my website and look at all the equipment I have in the car?

And how can the stereo signals be imbalanced when I've got 70 watts going to EACH front, and 25 going to EACH rear? It's not like I have 25 on the left side and 70 on the right. If you're talking about the signals from the HU then they're fine also. Why wouldn't they be? I've got inputs 1 and 2 running the fronts off the HU and 3 and 4 running off the rear outputs. When I fade front to back, I get front to back. When I balance right to left, I get right to left.

And ambiance has nothing to to with reverb or hall effect at all. Ambiance is the illusion that the speakers aren't in any given spot. Before I did this, all I could hear were the front speakers (duh), and all the sound came from the front. No fill whatsoever.

Now I have rear fill, which gives the car a more "concert" sound. When you sit in the car now, you can't even tell the back speakers are on, which is the way it's supposed to be, but if you lean back there or if I fade to the rear, you can hear them fine. But if I fade all the way to the front, it's obvious that the rears aren't there anymore.

And yes I am happy with it. But I don't remember asking anyone "How will it sound?" Did I?

YOUR problem is; you've never thought of it, so therefore you've never tried it, and therfore never
heard it, so you're quick to ASSUME that it won't sound good, or work right or whatever.

If you'd like, you can PM me and I can show you a complete diagram of everything, as well as the six different switches I have on that amp, and how I have them set, etc., etc. Then maybe you'll better understand it.

 

You're right, im jealous. :hail:
Jim can vouch for the fact that im more than experimental in my wiring approach in other posts, so im by no means locked into what manuals tell me i can and can't do. :P

How did you end up with 70W front and 25W rear for each channel? Isn't that amp a 75W max amp in bridged mode?

 

Well that's cool that you're also experimental...... at least we're both "mental".

It's a four channel amp. 25x4. Bridged into 2 channels is 70 watts. And that's not max.... that's RMS at .01% THD stereo..... .03% THD bridged. That's from 10Hz-50KHz ± 1dB. Come on!!!!! It's an Alpine for Pete's sake. I don't see "Crunch" written on it anywhere. EDIT: As a matter of fact.... Alpine never gave "MAX POWER" rating back then. They didn't believe in them, at least back then. I don't know about now.

This amp (as I said) has 6 switches on it to control what it does. It's crazy like that. I can't find the owner's manual right now..... but believe you me... you need it for this amp. There are 8 different diagrams on how you can hook up this amp that THEY show. And you know there's more than that .

From what I can remember..... it's got a Stereo/Mono switch for each of 2 channels. A HP/LP/Stereo for each of 2 channels. A 180* phase switch. ..... wait..... I found it

OK..... it has 2 gains..... one for 1+2, one for 3+4.

Then two HP/LP/Off filter switches...... one for 1+2, one for 3+4.

Next we have two Input Mode switches... which is selectable from "CH 1 (mono)" or "ST" or "CH 1+2" and another for "CH 3(mono)" or "ST" or "CH 3+4"

Then a switch for Input Channel selectable from "1/2" or "3/4" or "1+3/2+4"

And finally a 180* phase switch for channels 3+4 if you just want to run a sub(s) and be able to 'tune' it to the rest of the speakers.

IIRC, it cost me ~$400 back in 1988. I can run 2/3/4/5 or 6, four ohm speakers/subs off of it, some setups which need the help of passive crossovers (obviously). You can make it NON-Fading for subwoofers. You can run just about any configuration you like, obviously including your entire system. It's a very versatile amp, which is one reason I bought it.

The EQ I have is an 11 band (Alpine of course). It has fader control, a HP/LP infinitely variable crossover from 50-120 Hz @ 18db/octave on HP and LP, sub on/off switch, EQ on/off switch, sub volume from +0 to +15, 180* phase switch for sub, Stereo/Mono switch for sub. And it also has a Freq range of 10Hz to 50KHz ± 1dB. It cost me $250 in 1987.

FYI, I've had the RF Punch 100DSM since 1991 and I paid ~$400 for it.

As you can see..... I haven't bought a new amp for over 10 yrs. and I don't want to start now (unless I blow this one ).

AJ