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-   -   Syn 4 or JL MHD 750/1 for a pair of REV 10's (http://www.wakeworld.com/forum/showthread.php?t=796895)

cal2vin 02-09-2013 12:35 PM

Syn 4 or JL MHD 750/1 for a pair of REV 10's
Which amp, Wetsounds Syn4 or JL Audio MHD 750/1, sounds best/loudest on a pair of Wetsounds REV 10's. I know some people here have or are running these amps on these speakers. Who has heard both? Opinions?

david_e_m 02-09-2013 1:02 PM

I have heard both many times. Technically, the Wetsounds Syn4 might edge out the JL Audio HD750/1 in power at 14.4 volts supply based on the manufacturer ratings. The strictly regulated JL Audio HD750/1 will definitely have more power at 12.6 volts supply.
But here is what you need to understand. It is NOT the power difference. It IS the ratio of the power increase/decrease that makes the audible difference. For example, a 100 watt difference in the context of a 15 or 20 percent difference is inaudible. A 100 watt difference from 10 to 110 watts is gigantic in what you perceive.
So if someone says,"WOW, the difference between these two amplifiers in this application was .....this or that louder", you can take that statement as the result of the placebo effect. And, at the end of a rope at wake range against noise, forget it. No difference. After 10 minutes of railing on either system and the trauma to your auditory system, forget it. No difference. No difference on multiple accounts. So make your selection on other attributes but not on an anticipated volume difference.

Earmark Marine

Truekaotik 02-09-2013 1:57 PM

I have heard both as well... One is a bit more than the other price wise... But the added benefit is worth the small difference in price when comparing features. Hmmmm. Decisions...:-/ want to stay all one brand or mixing? Is price your main decision or features?

cal2vin 02-09-2013 3:01 PM

Well if probably get the jl used and I can already have a syn4 but need another as I'm running two pairs. There would be a price difference yes. But I'm not so worried about that. What features does one have over the other beside a regulated power supply which as david explained wouldn't really have an audible difference. I realize the mhd 750/1 is smaller but that also doesn't matter in my situation.

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cal2vin 02-09-2013 3:02 PM

I do already have a syn4.*** sorry. Typo

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chpthril 02-09-2013 5:20 PM


I do already have a syn4 but need another as I'm running two pairs
So you will be running 2 pair of Rev-10's? If so, then SD-2 all day long. Single amp to wire!

Truekaotik 02-09-2013 6:37 PM


Originally Posted by cal2vin (Post 1805782)
I do already have a syn4.*** sorry. Typo

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Then just run another Syn4....

david_e_m 02-09-2013 7:24 PM

Yeah, I agree that if you already have one Syn4 I don't see that there is a decision to be made.....go with a second Syn4.

Earmark Marine

cal2vin 02-09-2013 7:56 PM

The reason there is a decision to be made is because I have to replace the amp for my in boats as well so I could just use the syn 4 i already have on the in boats and get new tower amps if I decided to go with jl

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chpthril 02-09-2013 8:40 PM

Yep, move the current Syn-4 over to your in-boats and go with the SD-2 for 2 pair of REV-10.

cal2vin 02-09-2013 11:36 PM

I could go that route. But that would net a little less power to the speakers at 12.5 volts. probably 275 per speaker or so. I play the stereo a ton with the boat off.

david_e_m 02-10-2013 2:10 AM

Typically you lose 20 minimum to 25 percent of your power when going from a 14.4 volt supply (unrealistic) to a 12.5 volt supply. At rest you begin with 12.7 volts at best then decline in voltage as time passes. If measured at the amplifier's primary power terminals when under load you will find the voltage sags well below the static voltage. Everyone experiences this but no one notices a difference in volume without a minimum 25 percent reduction or a 33 percent increase in power with fresh ears. Natural masking and compression sets in after a very short period of loud music. You are not as sensitive as you think.
If you play the system a ton with the boat off then the focus should be on stiffening the voltage with greater battery capacity and having big AC shore re-charging capacity.
Anything below 12 volts (50 % reserves) is too low for a consumer grade deep cycle battery to last.
Besides, you can run good amplifiers into the ground with low voltage.
Strict regulation isn't a free ride either. The power supply works harder as the voltage gets lower.
Put a scope on the amplifiers during tuning to determine the very first sign of clipping. That will determine a maximum numeric value on the display of your source unit or remote. Stay disciplined as the day grows longer by adhering to that number. You can trust that number but you cannot trust your ears after a while. Driving the amplifiers into compression is extremely inefficient. And that gobbles current and really drops the voltage.

Earmark Marine

cal2vin 02-10-2013 6:52 AM

Yea right now I have two kinetik 1800s with a promariner prosport 20 and a kinetik 800 for the starting battery. I will likely need to upgrade batteries as I am also putting in a 2000 watt sub amp. (Audioque aq2200d). Completely off topic question.. When hooking amps to the battery bank should the positive and neg connection go to both the battery and just have the other paralleled onto it or should I use the pos on one bat and the neg on the other? I always thought the latter was the way to do it so that way you would be drawing from both batteries for sure. Correct me if I'm wrong.

Truekaotik 02-10-2013 7:30 AM

Hooking to one battery in the stereo bank is fine...

cal2vin 02-10-2013 10:13 AM

OK Ive been wondering that for a while but never got around to really searching for an answer.

chpthril 02-10-2013 11:52 AM


When two or more batteries are wired in parallel, then they become one large battery. So there is not difference between one battery's + or - from the other battery's + or +. So you can connect the amp's main ground feed to which ever is the shortest distance, easiest and cleanest to terminate to. As far as where the amps main B+ terminates, to, that will depend on what type of dual battery setup you have. If the stereo bank is a stand-alone bank just for the stereo, then yes, connect that B+ directly to the battery bank at either battery's + post. id you are using a traditional dual-battery switch, then the ideal location would be to the common post of the switch. If you are using a switch and an ACR, then it would terminate at the battery bank's B+ post.

cal2vin 02-10-2013 12:31 PM

1 Attachment(s)
The boat is a 2008 mastercraft x2. So it came with the ACR. I have disconnected that and the stereo bank is standalone and I charge it with the onboard charger whenever the boat is off water. Here is a picture of my setup to give you a better idea. I have 0 gauge connecting the two batteries in parellel and 0 guage running to distro blocks for pos and neg for the inboat amp and the old tower amp. (syn 4 and ppi p900.4). Then 4 gauge going straight to a kicker zx750.1 whcih is being replaced with an audioque aq2200d at 1 ohm so I will have to switch that to straigh 0 gauge run.

chpthril 02-10-2013 12:40 PM

Then as noted above, connect your amps' main B+ to either of the stereo batteries.

cal2vin 02-10-2013 1:09 PM

What do you mean by B+ just the positive lead from amp to power source?

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david_e_m 02-10-2013 1:19 PM

With the planned system you will need more batteries and a much, much bigger shore charger than 20 amps. Not larger related to charge time but larger related to the proper battery charging current.

Earmark Marine

chpthril 02-10-2013 1:47 PM


Originally Posted by cal2vin (Post 1805930)
What do you mean by B+ just the positive lead from amp to power source?

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B+ = Battery Positive. Regardless of the battery bank/switch scheme, the amp's ground (B-) will always terminate directly to the negative of one of the batteries. But depending on the battery bank/switch setup, the amp's battery positive (B+) may terminate at battery or the common post of the switch. Since you removed the factory Dual-Battery Switch and ACR, both of your amps main feed cable, (B- and B+) will terminate to your stand-alone battery bank.

I would also confirm where your source unit is terminating its B+ and B- at as well. They should share the same battery bank as the amps.

cal2vin 02-10-2013 5:52 PM

OK ic. So if I add another amp (possibly another subwoofer in the future) I can hook the pos from the second sub amp to the post on the other battery in the stereo bank because I'll already have 3 0 gauge connections to one post with my current system and my bat terminals (just got the knukonceptz ones) only have 3 connections. Just put another knukoncepts terminal on the other battery in the stereo bank?

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cal2vin 02-10-2013 8:12 PM

David, What size shore charger would you say I need? Any reccomendation on brands?

david_e_m 02-10-2013 8:29 PM

The final size of the battery bank determines the capacity of charger.

Earmark Marine

cal2vin 02-10-2013 9:10 PM

Then I guess my next question is what size/amount of batteries would you reccomend for this size system. 2 wetsounds syn4 for the pairs of rev 10s (1600 watts), 1 precision power p900.4 (4 ch @ 4 ohm so 600 watts), aq2200d @ 1 ohm (2000 watts). I know have over shot the estimates but that wont hurt to get bigger batteries. So right now Im looking at 4200 watts or so. I was thinking about just adding one more kinetik HC1800 and then the bigger charger. Would that be anywhere near large enough?

BradM07SS 02-11-2013 4:49 AM

We have close to the same watts I have 3600. I also have a aq2200, 2 skar 125.4 (800 rms each) , 1 for REV 10's and 1 for In boat speakers. I 'm running 4 AGM group 31's 105 AH each.


There pretty cheap for AGM battery and I believe Deka makes Duracell batteries.

david_e_m 02-11-2013 6:26 AM

There is no way to accurately answer that. But here are some rough numbers.
The Kinetik calculations do not consider play time at rest. And, I don't see an amp/hour rating on the Kinetiks but I'll guess that an 1800 is about 100 A/Hs.
You don't want to deplete the batteries below 50 % capacity (12.0 V). At rest, with an AGM, you may start with 12.8 volts max and decline from there. On average at full power at rest with the adjusted supply voltage you might be running around 3000 watts. Music is transient in nature so it's not a static calculation and there are a ton of variables. So to keep your batteries at no less than 50 percent capacity, you might pull down one 1800 per 1 to 1.5 hour at or near full output. A lot depends on how much compression, the accuracy of the specs, the efficiency impacted by system set-up & tuning, etc. Including your starting battery, if you added another 1800, for a total of four batteries, then you would want a 40 amp charger. If you added two more 1800s then I would use a 50 amp charger. We use Intelli-Power chargers that have 10 amp increments through the most popular applications.

Earmark Marine

cal2vin 02-11-2013 11:12 AM

The kinetik HC1800 is actually 81 ah. It actually did find it on their website. So sounds like Ill most likely need more than just one more. I may have to try bigger batteries instead of more smaller ones.

cal2vin 02-11-2013 11:13 AM

Brad, what sub or subs are you running with your aq2200d?

BradM07SS 02-11-2013 11:54 AM

I'm running 2 Sundown sa15's in ported enclosure tuned 33 hz..

cal2vin 02-18-2013 9:58 PM

How do those sound? Loud? Low?

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