Amp to Sub Wiring Advice


NicV

CarAudio.com Newbie
Jan 6, 2020
13
1
UK
Hi all this is my first post.

Audio novice hoping for some advice please. My car - 1995 MR2 - came fitted with a 2 Channel Rockford Fosgate Punch 40ix Amp (mounted under passenger seat) wired to 4 x 6.25” Rockford Fosgate Punch RFA64 Subwoofers (2 x subs mounted together in a box behind each seat).

I’ve removed the subs so I can better seal and sound deaden the housings and I’m curious to know why the subs have been wired in as they have. I’ve attached a couple of photos, one shows the wiring from the amp. The other shows wiring at the sub box (2 bridged subs removed) the wiring then goes to the other 2 bridged subs on the other side.

Am I right in thinking that all 4 subs have been wired in parallel to one output from the amp? Curious to know why it is wired like this instead of wiring each pair of subs to a separate channel? Would you leave it like this? Also curious to know what the part with the red label is and does?
 

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cbuts

CarAudio.com Elite
Sep 29, 2011
906
4
canada,ont
Hi all this is my first post.

Audio novice hoping for some advice please. My car - 1995 MR2 - came fitted with a 2 Channel Rockford Fosgate Punch 40ix Amp (mounted under passenger seat) wired to 4 x 6.25” Rockford Fosgate Punch RFA64 Subwoofers (2 x subs mounted together in a box behind each seat).

I’ve removed the subs so I can better seal and sound deaden the housings and I’m curious to know why the subs have been wired in as they have. I’ve attached a couple of photos, one shows the wiring from the amp. The other shows wiring at the sub box (2 bridged subs removed) the wiring then goes to the other 2 bridged subs on the other side.

Am I right in thinking that all 4 subs have been wired in parallel to one output from the amp? Curious to know why it is wired like this instead of wiring each pair of subs to a separate channel? Would you leave it like this? Also curious to know what the part with the red label is and does?
I'm probably wrong but my guess is the amps bridged to 1 ohm and the duals are dual 4 ohm wired to 1 ohm? I know nothing don't listen to me
 

02WS6

CarAudio.com Well Known
Jan 12, 2020
147
59
Sacramento
According to here: https://www.amp-performance.de/en/1293-Rockford-Fosgate-Punch-40ix-DSM.html

That amp runs at 172 Watts bridged @ 4 Ohm. Your photo shows the Amp wired in bridged mode.

Considering this is pretty old equipment and based on what little wiring I saw, I'm going to assume all four of your speakers are wired in a series-parallel configuration to provide the 4 Ohm load across all four speakers.

Like This:

19803
 
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NicV

CarAudio.com Newbie
Jan 6, 2020
13
1
UK
Thanks, yes that is exactly how they are wired in.

I am in the middle of installing a new Pioneer DEH-80PRS receiver and will be connecting the amp to the low rca output, should I leave the subs wired in as they are or would it be better to switch to left and right channels like this?
 

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02WS6

CarAudio.com Well Known
Jan 12, 2020
147
59
Sacramento
I would get rid of that Amplifier and connect each speaker directly to the speaker level outputs of your DEH-80PRS.

Right now each speaker is seeing 43 Watts RMS but they're all playing exactly the same thing. (Mono output) Which is great for Sub's but kills mid/high fidelity.

The Pioneer provides 50 Watts Max x 4 channels and will probably sound way better than how its currently connected.

If you rewire like in the photo you attached your 40ix amplifier will only produce 2 x54 Watts @ 4 ohms - split in half again, each speaker will only see 27 watts.

You wont see any front to rear controls because all the speakers are behind you but you will start hearing actual "Stereo" sound. Where different sounds come from the left or right speakers depending on how the Artist setup the song.

100% run new speaker wire from each channel of your deck to each speaker. Your ears will thank you.

Basically you can leave it how it is for "loud" but lower SQ, or direct wire to your HU and maybe be a little less loud but have a much better SQ.
 

02WS6

CarAudio.com Well Known
Jan 12, 2020
147
59
Sacramento
Also to add - I would be amazed if that Amp is still putting out RMS power. I think you'll be amazed what that DEH-80PRS can put out line-level wise until you're in a place to add a 4 channel amplifier. (If that is a long term goal or not)
 
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NicV

CarAudio.com Newbie
Jan 6, 2020
13
1
UK
Cheers for the advice, much appreciated, I hadn’t considered running the subs directly off the head unit and I’m unsure what I’d need in terms of wiring. If I give you my full spec could you let me know what you think I should do?

Head Unit: Pioneer DEH-80PRS
Front Speakers & Tweeters: 5.25” Infinity Reference 600cs
Amp: 4 Channel Pioneer GM-D1004
Subs: 4 x 6.5” Rockford Fosgate RFA64
Amp: 2 Channel Rockford Fosgate Punch 40ix

This is what I’ve got to play with at the moment, my plan was to connect to the 3 way rca outputs on the head unit like this:

Low: RF amp to RF Subs
Mid: Pioneer amp 2 channels to door speaker
High: Pioneer amp 2 channels to tweeters.

I have the interior of the car stripped at the moment so I can refigure if there’s a better way to connect things up.
 

02WS6

CarAudio.com Well Known
Jan 12, 2020
147
59
Sacramento
Cheers for the advice, much appreciated, I hadn’t considered running the subs directly off the head unit and I’m unsure what I’d need in terms of wiring. If I give you my full spec could you let me know what you think I should do?

Head Unit: Pioneer DEH-80PRS
Front Speakers & Tweeters: 5.25” Infinity Reference 600cs
Amp: 4 Channel Pioneer GM-D1004
Subs: 4 x 6.5” Rockford Fosgate RFA64
Amp: 2 Channel Rockford Fosgate Punch 40ix

This is what I’ve got to play with at the moment, my plan was to connect to the 3 way rca outputs on the head unit like this:

Low: RF amp to RF Subs
Mid: Pioneer amp 2 channels to door speaker
High: Pioneer amp 2 channels to tweeters.

I have the interior of the car stripped at the moment so I can refigure if there’s a better way to connect things up.
Ahh now I see the full picture - I was under the impression the four 6.25” speakers were the only speakers in the car.

Seeing as that isn't the case let me reverse my previous response and say this. Unless you're going to upgrade your sub and sub amp, leave everything connected for the sub's as is, as its the best you're going to get in its current config - 4 Ohm bridged to a series parallel load @ 4 ohms.

Everything else for your Mid's and High's sounds good.

My only recommendation would be to take some measurements a get yourself a shallow mount sub, find either a pre-fab box that meets the recommended cu/ft or build your own and a more powerful amp to match the RMS on the sub. I think you're mid's/high setup will over run what little bass you have. It's gonna sound clear as hell but everything below 100hz is probably gonna feel light.
 
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NicV

CarAudio.com Newbie
Jan 6, 2020
13
1
UK
Great that’s good to know.

I bought the car (Toyota MR2) with the RF amp and all the speakers fitted, but the Infinity speakers (plus 4” infinity speakers in the rear which I’m removing) were wired up directly to a 2012 Sony head unit. The sound quality was poor, too much base and not enough mid/high clarity. Once I started tearing the interior out to see what was actually fitted, I found that the speakers were very poorly installed with screws missing and no sealing or sound deadening, so I decided to strip everything out and start again.

This is the first time I’ve tackled car audio, after some research I opted for the new Pioneer head unit and amp. I’ve also read and watched a load of tutorials about how to properly install speakers, so that’s the first job on the list

The only thing I‘ve not yet sourced are the RCA cables for the Pioneer amp. I’ve been doing some research today and still not sure which to go with as there’s such a huge choice and prices vary massively. Any budget friendly recommendations?
 

02WS6

CarAudio.com Well Known
Jan 12, 2020
147
59
Sacramento
It sounds like you're definitely on the right track. I'm familiar with the MR2 just not the specific interior dimensions or what kind of room you have.

If you have any budget left I'd be happy to try and find a slim sub/enclosure for you just let me know.

As for your cables, take it from an electronics guy - Don't believe the hype when it comes to audio cables. More expensive or name brand cables don't do anything more than the Amazon specials. 99% of them have a +100% markup and aren't just worth the cost. For car audio RCA's the only thing I make sure of is that they're shielded just in case you're running wires together, it will minimize any interference of the signal passing through. As you're in the UK maybe try this Amazon link? (I would run these cables)


Measure from your HU, under your dash, down the side (or middle of the car) to wherever your amp will be placed. Measure twice and then order cables that are the closest to your measurement. Anything extra use zip ties to hide anywhere you feel is best. (Usually under the dash) Avoid anything "Car audio" branded as that just comes with additional cost and definitely avoid brick and mortar stores as they always have massive markups on cables.

As an aside, the only cables to really worry about in your car about are gonna be your power cables and if running a high powered sub the speaker wire gauge going to the sub. Stay away from CCA power cables and at your current power levels 8 gauge is more than enough, however if you're gonna get a larger sub/amp in the future go for 4 gauge. (These are US sizes I'm unsure of their metric counterparts.) Look around for welder supply stores in your area or search online if there are any in the UK and order something like this: https://www.acdcwireandsupply.com/4_AWG_SAE_WELDING_CABLE_p/wc-4g-03-dir.htm

Just find the UK equivalent and add an ANL fuse holder to the main power wire for safety.
 
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NicV

CarAudio.com Newbie
Jan 6, 2020
13
1
UK
Thanks for the link I’ll go with those. I did wonder today when I was reading up and found a 1m RCA cable that retailed for $4000!

For now I’m going to reinstall the RF subs along with the new upgrades and see how it all sounds together. If I do decide to swap out the RF parts there is this enclosure designed specifically for the MR2 https://mr2-ben.co.uk/products/811

Thanks again for taking the time to help, much appreciated.
 

Bobbytwonames

CarAudio.com Veteran
Aug 28, 2018
899
-124
Ahh now I see the full picture - I was under the impression the four 6.25” speakers were the only speakers in the car.

Seeing as that isn't the case let me reverse my previous response and say this. Unless you're going to upgrade your sub and sub amp, leave everything connected for the sub's as is, as its the best you're going to get in its current config - 4 Ohm bridged to a series parallel load @ 4 ohms.

Everything else for your Mid's and High's sounds good.

My only recommendation would be to take some measurements a get yourself a shallow mount sub, find either a pre-fab box that meets the recommended cu/ft or build your own and a more powerful amp to match the RMS on the sub. I think you're mid's/high setup will over run what little bass you have. It's gonna sound clear as hell but everything below 100hz is probably gonna feel light.
How dare you recommend a pre-fab box. That's utter blasphemy in here. He needs to go buy a shit load of tools and build his own. If he doesn't, he's just a lazy millenial, and his car audio will suffer. Check yourself! 😂😂😂😂 jk
 
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NicV

CarAudio.com Newbie
Jan 6, 2020
13
1
UK
I’m going to use the existing wiring between the RF Amp and RF Subwoofers but I had to cut the subs off as the wires were soldered to the terminals and there wasn’t enough spare length in the wire to be able to unsolder them.

The wiring is 12 gauge and my plan is to re-solder a short length of wire to the sub terminals and then fit a male/female plug to connect to the wiring to the amp (rather than splice them together). Question is, what type of plug/connector would be best to use? Bullet connectors or is there a better option?
 
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02WS6

CarAudio.com Well Known
Jan 12, 2020
147
59
Sacramento
I’m going to use the existing wiring between the RF Amp and RF Subwoofers but I had to cut the subs off as the wires were soldered to the terminals and there wasn’t enough spare length in the wire to be able to unsolder them.

The wiring is 12 gauge and my plan is to re-solder a short length of wire to the sub terminals and then fit a male/female plug to connect to the wiring to the amp (rather than splice them together). Question is, what type of plug/connector would be best to use? Bullet connectors?
Option 1: Best - Re-wire so that there are no additional connectors in the speaker wire lines.
Option 2: Better - Solder with fine flux core the additional connection and heatshrink the wires together.
Option 3: Good - Use a butt/spade/bullet crimped connection.

The reason for these options - For every connection an electronic circuit has there can be a small amount of voltage drop in that connection. The best option only has the connection from the headunit to the speaker, minimizing the amount of voltage drop as much as possible. (The HU connection and whatever the drop is over a given length of wire) The minute you start adding any additional connections to that circuit you can introduce additional voltage drops into the circuit degrading the quality of signal the speaker finally receives.

Any of the three options works, anyone on this board would recommend Option 1 as the best though. Its just up to you to decide which one you want to go with.
 
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NicV

CarAudio.com Newbie
Jan 6, 2020
13
1
UK
Thanks for that, option 1 it is then, if I’m going to do it I might as well do it right the first time.
 
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NicV

CarAudio.com Newbie
Jan 6, 2020
13
1
UK
I suddenly had a panic today that the Pioneer GM-D1004 Amp I bought to run my Infinity component speakers may be too much for them to cope with, as I’m struggling to find any specs for the 5.25” Pioneer 500cs speakers (Mids/tweeters).

I’ve attached the Amp spec sheet, can someone tell me what the minimum/ideal speaker spec would work?

thanks
 

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02WS6

CarAudio.com Well Known
Jan 12, 2020
147
59
Sacramento
Looks like 45w @ 4 ohm is what that amp is rated for. You may need to double check your component model numbers because earlier in the thread you said Infinity 600CS (Which doesn't exist) and now you're saying Pioneer 500CS (which also doesn't exist) AFAICT. Infinity 6000CS 6.5" or 5030CS 5.25's.
 
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NicV

CarAudio.com Newbie
Jan 6, 2020
13
1
UK
Looks like 45w @ 4 ohm is what that amp is rated for. You may need to double check your component model numbers because earlier in the thread you said Infinity 600CS (Which doesn't exist) and now you're saying Pioneer 500CS (which also doesn't exist) AFAICT. Infinity 6000CS 6.5" or 5030CS 5.25's.
The speakers are proper old school (as is the car) but they are in good condition and seem to be well made. There are no spec details marked on the speakers, this is the best info I’ve found on the net.

I started the audio upgrade only intending to replace the head unit but I’ve got a bit carried away now with the interior of the car stripped out so I can properly mount, sound deaden and seal the speakers. I’m now wondering whether these component speakers will work okay or if I should replace them. I don’t want to blow a load of money on new speakers but if I can find some decent spec used replacements I may be tempted.
 

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02WS6

CarAudio.com Well Known
Jan 12, 2020
147
59
Sacramento
With the power capacity listed, I'm going to assume that's max wattage so 37.5W RMS. Based on that as long as you set your gain correctly you should be fine. There are plenty of speakers in the 45W range in all comes down to what you want to spend money on.
 
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NicV

CarAudio.com Newbie
Jan 6, 2020
13
1
UK
With the power capacity listed, I'm going to assume that's max wattage so 37.5W RMS. Based on that as long as you set your gain correctly you should be fine. There are plenty of speakers in the 45W range in all comes down to what you want to spend money on.
Thanks I think I’ll try them and see how they sound.

Saying that I've started researching component speakers, looking around at used sets for sale, would these be a good choice?

Hertz Energy ESK 165.5 - used in good working order £75

Focal K2 Power 165 KR2 - used, current bid £50, what would these be worth?
 

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