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Bridging One Alpine S-W10D4 Dual 4 Ohm Sub to 2 Channels?

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Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
Printed Date: October 18, 2021 at 2:56 PM

Topic: Bridging One Alpine S-W10D4 Dual 4 Ohm Sub to 2 Channels?

Posted By: kenwood_nut
Subject: Bridging One Alpine S-W10D4 Dual 4 Ohm Sub to 2 Channels?
Date Posted: April 16, 2021 at 9:46 AM

Yes, I did a search here in the forum before posting this question. All I kept finding was posts about bridging 2 subs or bridging dual 2-ohm subs or bridging into one channel. My confusion lies in bridging a DVC Apline Type-S sub into 2 channels of a 4 channel amp. I've always bridged ALL my subs into 1 channel, but then all my subs were single voice coil, and I've always had TWO subs. This will be the first time I've ever ran a single sub (besides my current single 10" because it's a powered sub box, soon to go away). I only bought ONE sub due to a very limited space in my trunk because I have so many tools to haul around for work. MIGHT even put it behind my passenger seat inside the car. I got a Belva box for it.

I'm not 100% sure if I want to run my Nakamichi 4-channel amp to the single sub and the Eclipse 4-channel amp to the full-range OR the other way around, but since the Eclipse has a much more realistic RMS rating than the Nakamichi, the Eclipse seems like a better way to go for the sub. Nakamichi WAY OVER-RATES their RMS specs big-time I found out!

BUT, just in case I decide to run the Eclipse amp to the sub, because it has better power output specs, it leads me to my confusion!

Again, I've NEVER had a DVC sub in any car. I've bought them, but they never got installed. This Alpine S-W10D4 is my first. It has dual 4-ohm voice coils. What confuses me is the Eclipse amp shows an RMS output of 240 wpc into 2 channels at 4 ohms bridged. THAT confuses me! 2 channels?

The Eclipse shows which TWO terminals to bridge in mono under the speaker terminals, but THIS is only ONE channel. Right?

I have tons of diagrams I've found online about bridging different subs into bridged mono, but none show how to bridge into 2 channels. HOW in the world will I do this? Do I just wire each 4-ohm voice coil to a one side each of the left and right amp outputs? Had I known this was going to be so confusing, I might have just bought a SVC sub. I've never heard of bridging into 2 channels on a 4-channel amp, which is why I'm confused. When Eclipse says "@ 4 ohms bridged" do they mean two 4-ohm voice coils bridged?

PLEASE go easy on me if you reply. I'm 62 years old, and after many years of consuming too many Coronas, I may have lost a few brain cells and therefore aren't quite as sharp as some of you. Like I said, bridging in mono is simple for me, but bridging into 2 channels is new to me! I actually would never have even considered it had the amp specs not shown the RMS rating for 2 channels bridged.

Thanks! Oh, by the way, if anyone wonders, the model of the Eclipse amp is the PA5422. It has these ratings:
85wpc X 4 @ 4 ohms at 0.004% THD
120wpc X 4 @ 2 ohms at 0.008% THD
240wpc X 2 @ 4 ohms bridged with 0.008% THD
Pretty impressive THD specs I would say!

THIS is how I've always saw it done! Bridging into ONE channel. (I found this picture here at the12volt!) THIS is why I ask about 2 channels.


Posted By: kenwood_nut
Date Posted: April 16, 2021 at 9:56 AM
OR: Do I just run each voice coil to a left and a right channel? Is THAT what they're talking about?

If that's the case, I have room for another pair of speakers or another DVC sub. My tweeters will be happy to hear this!


Posted By: mgoetz74
Date Posted: April 16, 2021 at 1:45 PM
your diagram would be the way id do it. If the 2/4 channel amp is bridgeable then you would just use the left + and right - and bridge the amp. I've done tons of amp/subs with 4 channel amp and ran the front speakers to the front of the vehicle and a sub (or 2) off the rears this way. Only problem is your limited on power that a 4 channel will output compared to a mono and you'll have some extra heat since a class a/b amp isn't as efficient as a d class amp

31 years as a installer. Favorite thing to install/topic are remote starts/car alarms. Stop using test lights!!!

Posted By: kenwood_nut
Date Posted: April 16, 2021 at 1:56 PM
Awesome! I couldn't figure out why they would list bridging at 2 channels, but I'm guessing because I'm using 2. I can't believe how impossible it is to find a real manual for the Eclipse PA series amps, only the brochure.

I'm seriously wanting to run my tweeters off the front channels, but then it would seem if I'm bridging a sub that I can't set the mono/stereo switch on front OR rear, and can't adjust the HPF or LPF of either. Is that right? I don't CARE if I can, but it would be nice. My equalizer could pretty much do that, or the head unit. My new Nakamichi head unit has tons of filters and settings and even a 25-band equalizer built in.

So since you confirmed my assumption, sounds like it's the DVC sub to the 2 bridge points and the tweeters off the front channels!


Posted By: mgoetz74
Date Posted: April 16, 2021 at 2:03 PM
id just use the x overs in the head unit and not on the amp, don't want to get any bad cascading x over points and be missing a frequency some where. I haven't used anything eclipse since around 94 or 95 and had a few of those titanium subs (if i remember right) they use to make. The factory reps saw me using them in my civic @ a usac finals and sent me 2 more of those 12's and a really nice jacket

31 years as a installer. Favorite thing to install/topic are remote starts/car alarms. Stop using test lights!!!

Posted By: kenwood_nut
Date Posted: April 16, 2021 at 2:29 PM
mgoetz74 wrote:

The factory reps saw me using them in my civic @ a usac finals and sent me 2 more of those 12's and a really nice jacket
WOW! How awesome! So suddenly YOU were a rep! :) I've never had ANY system worth showing off at any kind of competitions! All my self-installs are nice and neat and correctly done with high-quality twisted OFC everything and carefully installed, and everything has always sounded awesome, but the only people I show off my system to are friends and family. LOL! I don't go for SPL's or earth-shaking, I go for crystal clear highs and VERY nice sound at low to moderate volume. People are so impressed by my present stereo that they all want me to put stuff into their rides! But every time someone gets into my car and I turn the stereo up, they start yelling for me to turn it down once I get past about 4 or 5 on the volume! Pansies!

Makes sense about the crossovers. The problem is, the head unit has crossovers and HPF's and LPF's and all, but then everything goes through a 7-band equalizer before it hits the amps. I'm thinking seriously about removing the equalizer since I bought this head unit. Why buy a deck with 3 sets or RCA outputs only to run ONE pair to the equalizer? Makes no sense to me, but the equalizer only has one pair of inputs and 3 pairs of outputs. Right now on my Nakamichi 4-channel, I did have everything set to high pass but now have it on full range just so I get a little more midrance out of the front and rear speakers.

Thanks for the advice! It really helped confirm what I needed to know! Like I mentioned, this is my first DVC sub so I was kinda worried about bridging it. Sounds pretty simple after all.


Posted By: i am an idiot
Date Posted: April 16, 2021 at 6:57 PM
That amplifier is not 2 ohm mono stable. Do not connect it as in your diagram. Look for the diagram that shows you an 8 ohm load, or connect 1 voice coil to the left channel and the other coil to the right channel.

You could, bridge channels 1 and 2 to one coil and bridge 3 and 4 to the other coil.

Posted By: kenwood_nut
Date Posted: April 16, 2021 at 11:01 PM
That is EXACTLY why I posted the original question! Because it shows specs for 2 ohms in 2 channels, not 1. BUT, it DOES have a mono speaker hookup diagram on it, so what would THAT mean? Why would it have a mono speaker connection if it's not 2-ohm stable in mono? Now I'm only getting MORE confused!

I can always use my Nakamichi 4-channel amp which IS 2-ohm mono stable, but I seriously think you're incorrect. At least to some extent. I really don't want to waste an entire 4-channel amp on just ONE sub, so I'd rather run my Nakamichi to the sub and run this Eclipse to the sub.

But rather than reply telling me this amp is NOT 2-ohm stable in mono, why wouldn't you explain it in more detail and answer my original post? HOW the heck am I supposed to bridge in 4 ohms with a DVC sub???

The way I see it, if an amp has a mono speaker hookup diagram on it, it MUST be mono capable. And since this amp only gives a rating at 2 channels, THIS is where my confusion comes in. But I'm certainly not going to run both voice coils off all 4 channels. That would be a waste of an amp.


Posted By: i am an idiot
Date Posted: April 17, 2021 at 6:12 PM
The Nakamichi amplifier listed in your signature is not 2 ohm mono stable. It is 2 ohm per channel or 4 ohm mono. How to bridge it into a 4 ohm load? Buy the correct speaker. Either a single 4 ohm or a dual 2 ohm.

Posted By: kenwood_nut
Date Posted: April 17, 2021 at 10:53 PM
Okay, several things you're wrong about here!

YES, the Nakamichi amp IS 2-ohm stable!!! I have the owners manual right in front of me! It claims to deliver 110 wpc RMS x 4 channels at 2 ohms! How can it NOT be 2-ohm stable??? You might want to do a little more research on amps before you post comments like that!

And "Buy the right speakers"? I'd bet MY speakers would blow YOURS out the door! I have 4 ohm full range, 3 ohm full range, and 2.5 ohm full range. What do YOU suggest, professor? I should buy 16 ohm speakers?

And I should by a "Dual 2-ohm" speaker???? WTH??? Why, so I can put bridge them in parallel into a half ohm load?

I'm not sure if you've had a few adult beverages or what, but you're totally wrong in everything you said in your comment!!!

And by the way, I wasn't asking about bridging into my Nakamichi amp, I was asking about the Eclipse!

I swear, THIS is the reason I hate online forums so much! People claim to know everything about everything but can't even get their facts straight when they comment on posts! I realize you're like a god here, but you're more like a devil when you comment on posts with nothing but hogwash! You're totally wrong in everything you said.


Posted By: i am an idiot
Date Posted: April 18, 2021 at 2:38 PM
Let ME go do some research on amplifiers.

I suggested a Dual 2 ohm driver so you could wire the coils in series to accomplish a 4 ohm load. But that may be hogwash to some.
Picture of bottom of page 5. Notice it has a woofer bridged to channels 3 and 4, notice it says 4-8 ohms. Notice the speakers connected in stereo to channels 1 and 2, it says 2-4 ohms.

The second line of page 6 in the manual reads. And I copy and paste: ● Use speakers with an impedance of 2Ω or 4Ω (4Ω to 8Ω when used as bridged amplifier)

The eclipse amplifier is not 2 ohm mono stable either. It too is 2 ohm per channel or 4 ohm mono stable.

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