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Stereo Upgrade Amp Advice - 2008 Malibu 247


EchelonMike

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Hi all, I am working on my stereo upgrade for the off season and need some help/advice from the Crew experts.  I am replacing the original JBL black box stereo with a Polk PA4A marine head unit that I have had collecting dust on my basement shelf for several years.  It is also a black-box style marine receiver, and the control interface will fit perfectly in the place of the JBL control in the walk-thru bow area.

I have recently replaced all of the boat's speakers.  There are 8 in-boat JL Audio M3 6.5" Coax speakers, and two M3 7.7" speakers on the tower.  The speakers are mounted and wired back to the current amp and head unit in the port side storage area.

I am adding a Kicker 10" marine enclosure subwoofer.  It's 2 Ohm, 400W RMS rated.  My boat is a Sunscape, so it has two captains chairs vs the rear facing seat on the port side.  In front of the port side captain seat is a HUGE storage space.  Its opening reminds me of a dog house door...will be perfect for the 10" sub.  The black box receiver is also there, as will all the amps, dual batteries, etc.

So...here are my questions:

   - I need new amplification for 10 speakers and a sub.  What are some good options?

   - The PA4A head unit only has two pairs of RCA and no sub RCA output.  How do I connect what I assume will be multiple amps to power it all?  Can I use a Y cable for the RCAs?  Is there one big amp that can do the job?

   - I'm assuming I'd set the 6.5" speakers for high pass; not sure about the towers.  Would they be best to set as full range?

   - Is there any reason to consider using the built in amp in the Polk receiver?  I'd rather not do that unless it makes sense to do so.

Here's my initial diagram, minus the amps:

image.thumb.png.58bfbab6811683a57809a3768c413e4d.png

 

Thanks in advance for your thoughts!

 

 

 

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Well I can’t answer your questions but mine (09VTX) is in the stereo shop right now getting an upgrade from the same original JBL stuff you have. Went with the Rockford Fosegate PMX8BB and the PMX8DH head. Bummer it won’t tie into the MUX switches but what I’ve gathered is nothing will anymore. Different interface software these days is what I’m told. Will the Polk communicate with the Maliview and MUX switches?

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8 hours ago, shawndoggy said:

Budget?

If I can stay at $1K or under that would be ideal.  I'll pay more if needed to integrate easily or to come up with a one-amp solution for it all. 

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8 hours ago, IJM said:

Well I can’t answer your questions but mine (09VTX) is in the stereo shop right now getting an upgrade from the same original JBL stuff you have. Went with the Rockford Fosegate PMX8BB and the PMX8DH head. Bummer it won’t tie into the MUX switches but what I’ve gathered is nothing will anymore. Different interface software these days is what I’m told. Will the Polk communicate with the Maliview and MUX switches?

I have not found anything that will work with the Mux switches.  I think the Mux power on/power off is about all that will stay.  I'll delete the rest of the volume buttons once the install is done.

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There are a few 5 chnl amps that would power a 2 ohm woofer just fine, but 8 speaker on the 4 full-range channels it a hefty load. An ideal setup would be a 6 or 8 channel for the 8 cabin speakers, a mono amp for the woofer, then bridge a mild 4 chnl for the tower speakers, that would deliver in the 150-225 watt rms range. 

With 2 pair of RCA outputs, you would dedicate one pair to the tower amp and the second to the cabin and woofer amp(s). 

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Supply chain shortages are really making this difficult to stay in budget.

I'd look at the JL Audio RD Series.  

RD 900/5 for cabin speakers (two speakers on each of the four full range channels, and your sub on the sub channel): https://www.crutchfield.com/p_13698642/JL-Audio-RD900-5.html?awcp=&awcr=309975518873&awdv=c&awkw=jl+audio+rd900+5&awmt=p&awnw=g&awug=9030895&gclid=CjwKCAjwiY6MBhBqEiwARFSCPvChrkTbHhPBkNR0k2QA1f6Ds_txuPiNZ1YeGsASoWGXwnIRI5mfaxoCuWwQAvD_BwE

(as MLA points out, this will be asking a lot of your amp, running everything at the lowest possible impedance -- not optimal, but in budget)

and 

RD 400/4 bridged to two channels for the towers: https://www.crutchfield.com/p_13698621/JL-Audio-RD400-4.html

That busts your budget by $100, but you get two pretty good amps.  I'd probably also spring for a remote level controller for the sub.  https://www.crutchfield.com/p_136RBC1/JL-Audio-RBC-1.html. Very nice to quickly adjust the volume of the sub without having to dive through headunit menus.

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15 minutes ago, EchelonMike said:

I have not found anything that will work with the Mux switches.  I think the Mux power on/power off is about all that will stay.  I'll delete the rest of the volume buttons once the install is done.

Yup it’s a bummer. Being the head is on the side wall in the walkthrough I used the MUX switches all the time. Especially when surfing, skiing, and wakeboarding to lower or mute the volume when my rider went down. Solved it by having stereo shop mount a second small remote head just in front of the throttle on the sidewall. Not the ideal location but our vintage boats don’t have any spare room on the dash area to mount anything. Should be getting some photos of the completed install from the shop today. Post some pics when I do. 

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1 hour ago, MLA said:

There are a few 5 chnl amps that would power a 2 ohm woofer just fine, but 8 speaker on the 4 full-range channels it a hefty load. An ideal setup would be a 6 or 8 channel for the 8 cabin speakers, a mono amp for the woofer, then bridge a mild 4 chnl for the tower speakers, that would deliver in the 150-225 watt rms range. 

With 2 pair of RCA outputs, you would dedicate one pair to the tower amp and the second to the cabin and woofer amp(s). 

Thanks for the input.  For the RCAs, how do I "share" across the Amps?  Just a Y cable?

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1 hour ago, shawndoggy said:

Supply chain shortages are really making this difficult to stay in budget.

That busts your budget by $100, but you get two pretty good amps.  I'd probably also spring for a remote level controller for the sub.  https://www.crutchfield.com/p_136RBC1/JL-Audio-RBC-1.html. Very nice to quickly adjust the volume of the sub without having to dive through headunit menus.

Thanks for the amp suggestions.  I'm a fan of JL audio so I'll zero in on these!

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15 minutes ago, EchelonMike said:

Thanks for the input.  For the RCAs, how do I "share" across the Amps?  Just a Y cable?

If you end up with an for the cabin and amp for the woofer, there may be a pass-thru on one amp or just use a pair of Y cables and split to both amps. 

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2 hours ago, EchelonMike said:

Thanks for the amp suggestions.  I'm a fan of JL audio so I'll zero in on these!

I would also strongly consider a zone controller (equalizer).  It would help you in several ways: 1 -- much higher voltage to the amps, so gains are lower and potential for noise is reduced; 2 -- you'd have three high powered RCA outputs (cabin, tower, sub) so no splitters required; 3 -- you'd gain an easily accessed AUX input; and 4 -- most importantly you'd be able to control the zones with a quick turn of some knobs (this would also be in lieu of the sub control I linked above).  The ability to fade between the tower and the cabin, as well as the ability to turn the sub up and down can't be understated.  With a zone controller you can do that in less than a second, by touch once you learn the knobs.

Wetsounds WS420 would be the gold standard.

I installed the much less expensive Memphis MXAEQ7 over the summer, and so far I'm quite impressed for the money.  Fit and finish is not up to wetsounds, but the sound quality is fantastic.

https://creativeaudio.net/mxaeq7/

 

Edited by shawndoggy
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Just got the pics. Looks pretty good. Not too thrilled about the small remote head location by the throttle but no other choice. 

424DA36E-4541-4AA0-9E70-C7006582056D.jpeg

B9EF082E-C1AD-4922-9DFF-3A39199CC573.jpeg

D6189D70-DDC7-453B-B4D1-C1B5BCB4A054.jpeg

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@IJM that looks nice - I like the second remote by the driver.  Agree with you that the companionway walk-thru is a lousy location for mounting the main control panel.  Hard to reach.  We mainly use tunes when we're sitting/floating vs underway, so it's less of an issue.  The Polk head unit is supposed to have a companion app so I am hoping I can get some control from my phone if needed.  Also, I like the controller that @shawndoggy recommended.  I could mount that under the helm and get some level control from there also.  Actually, that controller is probably all I really need since 99% of what we listed to is streamed from Spotify via Bluetooth.  :-) 

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If mostly what you do is stream, the other thing I added was a dash-top phone mount with qi charging.  That way my phone is in my line of sight and getting charged all the time.  I don't really even look at the HU any more, just the phone, and I can control the volume, fade between tower and cabin, and adjust the sub level by touch with the zone controller/eq.  I had to take some deep breaths before drilling the holes in the dash, but it works REALLY well.  Combined with a gps volume control app like volumatic or swift volume and it's really pretty fantastic.

image.thumb.png.bd75e1f9a292e55f45768d46e4e54ef7.png

 

 

Edited by shawndoggy
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I did a little research, and it looks like the old JBL equipment is controlled by a simple serial protocol on an RS485 bus.  The Polk seems to use their proprietary JDAB protocol on a CAN bus.  One could get the MUX control going by writing a bridge program on a tiny ARM controller, but figuring out JDAB would be key.  If you happened to have the Polk remote control, that should be fairly simple using a scope and a CAN sniffer.  The bridge controller would then allow you to continue to use your regular MUX control.

By the way, the folks on the other boating sites are not all enamored with their Polk units....

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@EchelonMike Thanks. Looking forward to testing it out next weekend at the lake. Even with the few negatives we're chatting about I think overall I will be happy with the upgrade. As will you I'm sure.

 

@shawndoggy I plan to use a companion app as well. My wife claims DJ role 99% of the time so the most control I usually get is the mute button when needed. LOL. I like your phone cradle mount. I need one of those for my nautical mapping app I use frequently for returning to the dock at night and navigating the shallows in the Colorado river.  Big PIA having to hold my phone. Looking into RAM mounts for this.

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@justgary Agree, I’ve thought of your idea too. Bridge it somehow. I’m sure there is plenty of older Bu owners out there, and other boat owners that would love a solution for this problem.

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10 hours ago, IJM said:

@EchelonMike Thanks. Looking forward to testing it out next weekend at the lake. Even with the few negatives we're chatting about I think overall I will be happy with the upgrade. As will you I'm sure.

 

@shawndoggy I plan to use a companion app as well. My wife claims DJ role 99% of the time so the most control I usually get is the mute button when needed. LOL. I like your phone cradle mount. I need one of those for my nautical mapping app I use frequently for returning to the dock at night and navigating the shallows in the Colorado river.  Big PIA having to hold my phone. Looking into RAM mounts for this.

Why ram mounts?  I just gave you a link for a marine rated version with a built in charger. 

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I have multiple RAM mounts I use in other vehicles and have been really happy with them. I’m leaning towards a suction cup one. Attach it to the side window and with their multiple custom elbows and such position it where I want. Never had a problem with them falling off either.

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So, quick update on my project.  I took @shawndoggy's advice and ordered the Memphis 7 band EQ controller.  I've decided I am not going to touch the JBL stock head unit and just leave it as-is, and am also not going to use the Polk Audio marine head unit either.  I already have a JL Audio MBT-RX Bluetooth adapter, which I was feeding into the headphone jack on the JBL head unit.  I am going to use this to feed the input on the Memphis Audio controller.  I'll then feed RCA's to the amplifiers for the Sub, tower and 8 in-boat 6.5" speakers.  

Still working on which amps to go with.  Avoiding a new head unit makes this project a lot easier to wire, and I think I'll end up with better audio performance too.

Thanks all!

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MBT-RX into the memphis is the exact setup we were using, and it was** awesome.  I also did a HU replacement at the same time.  The MBT-RX went to the EQ's aux input and the HU in the main input.  We never used the main input on the water, opting to use the BT feed from the MBT-RX exclusively.  If you use an iphone, pair it with volumatic or swift volume, and you also get fantastic speed based volume control (turns phone's BT volume up and down based on gps speed).  

**boat got towed off into the sunset on Friday.

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21 minutes ago, shawndoggy said:

**boat got towed off into the sunset on Friday.

Noooooooooooooooo!  Hopefully a new one is en-route to replace it!  

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