242X Stereo - How to Exploit Free Unused Watts

[Rod5]

I did a pretty big upgrade to the factory 242x system. Added WetSounds EQ 420BT, REV 10's and Punch Amp to power REV 10's, and another Polk 10” IB Sub. Oh and finally installed the Sea Deck from our Fall group buy.


Here's the awesome free part! Our Polk 5005.5 amps Sub output is 200w at 4 ohms or 400w at 2 ohms, but our factory subs are 4 ohms so adding another 4 ohm Sub in parallel tapped 200w of unutilized power from the amp for Free! It made a HUGE difference and seems like it woke up the original single sub. Truly sounds like tripling the Bass instead of doubling down…

 

[swatski]

Awesome mods and a tweak!

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[Rod5]

You mean in parallel, right? That is an awesome tweak!

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Yes meant parallel, I'll edit and fix. Thanks for letting me know!

 

[David Analog]

Not surprising because doubling the power PLUS doubling the sub surface area gives you a 6 dB increase. It would take a bit more than that (a 10 dB increase) to create the perception of twice as loud for fullrange, however, low bass requires a little less to give the perception of more. Our human perception is not a linear function. So you really DID double the bass output.
Btw, Polk Audio doesn't really make an IB subwoofer, despite the promotional propaganda. They're all low 'Qts' subs designed for small sealed enclosures. When used in an IB application, they will handle less power, but go very deep, lose tonal construction, create more tactile vibration, and lose attack/transients. Up to a point the subs do okay, just don't over-drive them. The mechanical suspension (spider) will prematurely fatigue and they get looser and looser over time.

 

[robert843]

@David Analog I'm going to high jack this thread for a second instead of starting a new one. If I use a 4 channel amp and want to run 6 speakers on it if I run the rear two channels in parallel to power 4 speakers will those two channels produce the 2 ohm power or is this a big no no to have 2 of the 4 channels running at different ohms?

 

[Drift Away]

Not surprising because doubling the power PLUS doubling the sub surface area gives you a 6 dB increase. It would take a bit more than that (a 10 dB increase) to create the perception of twice as loud for fullrange, however, low bass requires a little less to give the perception of more. Our human perception is not a linear function. So you really DID double the bass output.
Btw, Polk Audio doesn't really make an IB subwoofer, despite the promotional propaganda. They're all low 'Qts' subs designed for small sealed enclosures. When used in an IB application, they will handle less power, but go very deep, lose tonal construction, create more tactile vibration, and lose attack/transients. Up to a point the subs do okay, just don't over-drive them. The mechanical suspension (spider) will prematurely fatigue and they get looser and looser over time.

You certainly seem to be in the know with it comes to the audio game. Whats your take on running these boat amps at 4 ohms? I have ran my old orion 225 HCCA back in the day down to a 1/4 ohm with 2 DVC JL 12W6's and that monkey got hot as hell. Pretty sure no one is trying that in a boat (besides trying to find the old "cheater" comp amp is next to impossible). But as i understand it the lower the ohm the harder the amp is working and heating up. Since most of us are out in the sun in the summer seems like a great way to wear out a amp or worse.

 

[Rod5]

I ran the heck out of it at 2 ohms all afternoon Saturday with no issues. In fact it was no warmer than the other Polk 4004.4 amp.

 

[Julian]

@Rod5 what is involved in wiring in the Eq?

@David Analog what would you think about isolating the Sub in the side wall somehow? How small of a space does the polk sub ideally want? Was wondering if it would make sense to seal off the area that it is in with something.....

 

[David Analog]

@David Analog I'm going to high jack this thread for a second instead of starting a new one. If I use a 4 channel amp and want to run 6 speakers on it if I run the rear two channels in parallel to power 4 speakers will those two channels produce the 2 ohm power or is this a big no no to have 2 of the 4 channels running at different ohms?

This is commonly done. I can only think of two multi-channel amplifier models that require symmetrical front and rear loads. So don't give it another thought.

 

[David Analog]

You certainly seem to be in the know with it comes to the audio game. Whats your take on running these boat amps at 4 ohms? I have ran my old orion 225 HCCA back in the day down to a 1/4 ohm with 2 DVC JL 12W6's and that monkey got hot as hell. Pretty sure no one is trying that in a boat (besides trying to find the old "cheater" comp amp is next to impossible). But as i understand it the lower the ohm the harder the amp is working and heating up. Since most of us are out in the sun in the summer seems like a great way to wear out a amp or worse.

Modern quality amplifiers run safely at a 2-ohm load. A little more distortion. A little less efficiently. More power. Less headroom. No reason at all not to do it. My only concern is the extreme, when you have a multi-channel amplifier (like a 6-channel) that is loaded down to the minimum impedance on ALL six channels. Maybe sharing the most difficult job of subs + tower speakers. The single chassis sink and shared power supply can be tested on a July/Aug afternoon. But normally with a good distribution plan and loaded down to the minimum on most channels, but not all, wouldn't concern me a bit. The impact of low voltage concerns me more. If I ran a party yacht with a gen near full output 24 hrs. for long holiday weekends, then I would take many precautions, one of which might be strictly 4-ohm loads. But that is another extreme.
Cheater amplifiers, lower-voltage high-current amplifiers intentionally designed to run at low impedance loads to circumvent the rules of contest power classes, are a different breed. Horribly inefficient. Singular purposed.

 

[swatski]

@robert843 after confirming in another thread in here, I also use one of my mini amps (Clarion xc1410) to drive two DBs at 4 ohms (on their own channels) and 4 DBs at 2 ohms (sharing channels). Call me crazy, but the ones at 2 ohms seem louder, and the setup works great in tests.

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[David Analog]

@Rod5 what is involved in wiring in the Eq?

@David Analog what would you think about isolating the Sub in the side wall somehow? How small of a space does the polk sub ideally want? Was wondering if it would make sense to seal off the area that it is in with something.....

About .6 to .65 net sealed for a 10-inch sub. To use the air trapped in the enclosure to correctly damp and control the cone movement, the enclosure must be perfectly airtight. Isolation inside the gunnel would be a huge task and very hard to get right. I wouldn't bother with it. The Polks are actually good performing subs when used in the right application. I'd baby them for a season or two and then replace them with a true IB sub.

 

[Rod5]

The WS EQ requires running 4 sets of RCA’s and the remote lead from the Port storage locker where the Amps and Polk head units are located. 1 RCA is the input from the head unit, 1 RCA Sub output, 1 RCA for Tower Amp, 1 RCA for the cockpit or rest of the boat, you will need to split this one if necessary.

We removed the factory sub to gain access under the floor to the fuel tank compartment, ran wires around the front perimeter of the fuel compartment the back under the helm floor. You can pick up the constant power & ground in the helm for the EQ.


@David Analog These Polk Subs are inexpensive (about the cost on one fill up) so I don’t see any need to be nice or easy on them… We beat the hell out of the one factory sub all last year and it’s still going strong. For context, we put over 90 hours on our motors in one season last year (more than double the average) plus hours party cove and sand bar time. However we did blow two Polk DB6.5’s last year and replaced those with the Polk MM series…

 

[Rod5]

By the way, I use the Blue Tooth of the WS EQ to play music from my phone which has turned out to be WAY more cleaner than the streaming through the Polk head unit. Also the main reason I got the EQ was because of the now dedicated master volume on the EQ eliminating all the back and forth between the Conex launch/speed control screen and Stereo volume screen. I’m sure those of you with the X boats can appreciate what I’m talking about…

 

[David Analog]

@David Analog[/USER] These Polk Subs are inexpensive (about the cost on one fill up) so I don’t see any need to be nice or easy on them… We beat the hell out of the one factory sub all last year and it’s still going strong. For context, we put over 90 hours on our motors in one season last year (more than double the average) plus hours party cove and sand bar time. However we did blow two Polk DB6.5’s last year and replaced those with the Polk MM series…

That might be a good conversation for another time and another thread. Good subwoofer performance is much like matching the vehicle weight, coil springs, and shock absorbers. Not every combination works well. Nor is everyone going to appreciate the fine tuning.
Getting past that issue, you've done a great job on your system.

 

[Rod5]

Got it David and thank you those are all very fair points! When the time comes I will probably try out the JL IB subs or perhaps something else recommended then I'm sure I'll be saying why did I wait so long and you'll have every right to say hey remember when...

 

[swatski]

By the way, I use the Blue Tooth of the WS EQ to play music from my phone which has turned out to be WAY more cleaner than the streaming through the Polk head unit. Also the main reason I got the EQ was because of the now dedicated master volume on the EQ eliminating all the back and forth between the Conex launch/speed control screen and Stereo volume screen. I’m sure those of you with the X boats can appreciate what I’m talking about…

Just don't let your kids (if you have any) get any ideas about the "talk-back-mic" being a karaoke machine, lol.
I loved the WS420, and so did my kids. It is (almost) a must have once tower speakers are involved.

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[Rod5]

Just don't let your kids (if you have any) get any ideas about the "talk-back-mic" being a karaoke machine, lol.
I loved the WS420, and so did my kids. It is (almost) a must have once tower speakers are involved.

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Hahaha I so remember you said that on another thread! I use that one out of your play book to threaten our college kids (who all HATE karaoke with a passion) that I will karaoke and through down some serious old school raps while they surf if they don't behave... Ha such good times!!

 

[gatorsnga]

I did a pretty big upgrade to the factory 242x system. Added WetSounds EQ 420BT, REV 10's and Punch Amp to power REV 10's, and another Polk 10” IB Sub. Oh and finally installed the Sea Deck from our Fall group buy.


Here's the awesome free part! Our Polk 5005.5 amps Sub output is 200w at 4 ohms or 400w at 2 ohms, but our factory subs are 4 ohms so adding another 4 ohm Sub in parallel tapped 200w of unutilized power from the amp for Free! It made a HUGE difference and seems like it woke up the original single sub. Truly sounds like tripling the Bass instead of doubling down…

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This looks awesome! I love the second sub- Brilliant!
What amp was pushing the Polk tower speakers? Did you just terminate these wires? I have been curious if the Polk tower speakers were running in parallel or series with other speakers. I can't find a wiring diagram for the speakers and amps anywhere online. Do you have a wiring diagram?

 

[Rod5]

Yes just terminated the wires in the tower and ran new heavier gauge for the REV10s. No diagram,but from testing determined the following:
The original tower cans are on the front chan of the smaller amp at 4 ohms at 125w each, the swim platform is on the rear chan of the small amp also 4 ohms at 125w each. So now the front chan is unused, will come back to this point.

The big amp is running the bow at 4 ohms 70w each, rear chan is rear cockpit 6.5's and the sound bar in series (not sure why they did it this way), not sure of the ohms but that chan is also only 70w at 4 ohms, finally the sub is factory at 200w/4 ohms and per the specs has the ability to go to 1 ohm at 500w or my choice 400w at 2 ohms.

My phase 2 plan is to move the rear cockpit speakers to the now unused front chan of the smaller amp (125w vs 70w), install helm 6.5's like Julian and others have done tied to the soon to be vacant rear chan of the large amp, 70w should be fine right next to me and wife. Not sure what to do with the sound bar, but I bet it could use much more power than the current setup. May also up size the swim platform to the JL 7.7's soon too.