Notices

How many speakers on JL 900/5 amp?

Old 08-10-2012, 06:59 AM
  #1  
Senior MemberCaptains Club Member
Thread Starter
 
ScarabChris's Avatar
 
Join Date: Jul 2005
Location: Dania Beach, FL
Posts: 28,075
Default How many speakers on JL 900/5 amp?

Currently I have two pairs of the JL 7.7 components and two 10" JL subs on the amp. Each 7.7 has it's own channel and the subs share the 5th channel.

I have one pair in the gunwales facing right between the console and lean post (thinking of myself of course) and the other pair in the gunwales in front of the console.

So since everyone hangs out in the rear seats when running I keep getting requests to "turn the music up man" because they can't hear it very well all the way in the back of the boat. But when I turn it up so the back seat captains can hear the music it then becomes a little too loud for my liking at the helm.

So I was thinking of adding another pair of 7.7's in the back of the boat.

Better to get a 7 channel amp or will it sound OK tapping the new back speakers to the center speakers?
ScarabChris is offline  
Old 08-10-2012, 07:17 AM
  #2  
Admirals Club Admiral's Club Member
THT sponsor
 
Join Date: Jul 2010
Location: On the Flats
Posts: 7,221
Default

Chris,

I had similar questions myself last year. JL techs will tell you that the JL 900 has enough power to run two 7.7's on each channel and two 10 inch subs on the sub out line. This set up sounds great...but some guys double down to keep one 7.7 in each channel and a mono line going to each sub. All depends on your listening style and how loud you crank it up! The 900 running just one sub...certainly has enough power to kill a single 10inch!

As long as you calibrate the JL900 according to JL protocol to get the outputs adjusted to preventing clipping and keep the sound clean....hook up the other pair with no fear and see if it works for your needs.

The amp can certainly handle it.

Good Luck
Flatout71 is offline  
Old 08-10-2012, 08:17 AM
  #3  
Senior Member
 
MB Marine Electronics's Avatar
 
Join Date: Oct 2011
Location: Pompano Beach, FL
Posts: 1,110
Default

You can definately add another pair of speakers to that amplifier, but because of the design of the MHD amps it will not make any more power even though you are lowering the OHM load. Therefore you will only get half of the power to the speakers you add and the speakers that are already on the channels you are adding them to. This is why most will get another amp. You might be fine with it. It sounds like you need more speakers either way so add the speakers and then if you dont like it add another amplifier.
MB Marine Electronics is offline  
Old 08-10-2012, 08:22 AM
  #4  
Senior MemberCaptains Club Member
 
Join Date: Dec 2007
Location: PBG, FL
Posts: 8,933
Default

The 900 actually cuts its power to 75 watts at 2 ohms. So not only r u cutting half the power to speakers but ur getting half of a reduced output. Maybe just run the pair of 7s at the helm off the head unit and put the new speakers in the rear on the amp then u won't get blown out at the helm and they can hear it.
bradv is offline  
Old 08-10-2012, 08:40 AM
  #5  
Admirals Club Admiral's Club Member
THT sponsor
 
Join Date: Jul 2010
Location: On the Flats
Posts: 7,221
Default

You only loose only 25 watts going to 2 ohms. That is only 1/4 not half of the power. In most cases you will still get better quality sound running the second set of speakers off the JL. If you happen to have a Fusion deck their deck output is pretty powerful and clean. Others I have tried are rarely adequate.

Rated Continuous (RMS) Power @ 14.4 V
Main Channels @ 4 Ω 100 W RMS x 4
Main Channels @ 3 Ω 75 W RMS x 4
Main Channels @ 2 Ω 75 W RMS x 4
Main Channels @ 1.5 Ω 75 W RMS x 4
Main Channels - Bridged @ 8 Ω 200 W RMS x 2
Main Channels - Bridged @ 4 Ω 150 W RMS x 2
Subwoofer Channel @ 4 Ω 500 W RMS x 1
Subwoofer Channel @ 3 Ω 500 W RMS x 1
Subwoofer Channel @ 2 Ω 500 W RMS x 1
Subwoofer Channel @ 1.5 Ω 500 W RMS x 1
Flatout71 is offline  
Old 08-10-2012, 08:47 AM
  #6  
Senior MemberCaptains Club Member
 
Join Date: Dec 2007
Location: PBG, FL
Posts: 8,933
Default

Yeah 75 on the channel divide 2 speakers so 37.5 to each speaker
bradv is offline  
Old 08-10-2012, 09:13 AM
  #7  
Admirals Club Admiral's Club Member
 
Join Date: Apr 2011
Location: Florida
Posts: 513
Default

Chris,

I have 6 7.7's on my M700/5 and they sound great. But the information above makes it look like the HD amps are different.


Let me know if you need some fiberglass speaker boxes for JL 7.7's under the gunnel in the rear. I bought a couple that wouldn't fit under my rear gunnel (it's too narrow...put the speakers in the foothold). The boxes are pretty nice...I haven't listed them yet, but bought them from the guy at the link below.

http://www.thehulltruth.com/sms-smar...l-install.html
OtisMyMan is offline  
Old 08-10-2012, 09:30 AM
  #8  
Senior MemberCaptains Club Member
 
Join Date: Apr 2007
Location: Miami, FL
Posts: 2,519
Default

Originally Posted by bradv View Post
The 900 actually cuts its power to 75 watts at 2 ohms. So not only r u cutting half the power to speakers but ur getting half of a reduced output. Maybe just run the pair of 7s at the helm off the head unit and put the new speakers in the rear on the amp then u won't get blown out at the helm and they can hear it.

Best idea other than getting a second amp.
Pipo6007 is offline  
Old 08-10-2012, 11:01 AM
  #9  
Senior MemberCaptains Club Member
Thread Starter
 
ScarabChris's Avatar
 
Join Date: Jul 2005
Location: Dania Beach, FL
Posts: 28,075
Default

Yes I have a Fusion IP600 head unit. Maybe I will do that.
ScarabChris is offline  
Old 08-10-2012, 11:23 AM
  #10  
Admirals Club Admiral's Club Member
 
Join Date: Jan 2011
Location: Birmingham/Orange Beach
Posts: 214
Default

I have two 900/5's, 4 6.5's on each amp. Each amp also has 1 JL M10. Sounds great, you could buy one more 900/5, 4 more speakers and split your subs between the two amps. I started out like yours is now, added the amp, and got much more bass once each sub had 500 watts. That totals out at 8 speakers and 2 subs. That way your amps aren't working very hard to push the subs. FYI: I also have the Fusion IP600.
cbraz82 is offline  
Old 08-10-2012, 11:49 AM
  #11  
Senior MemberCaptains Club Member
Thread Starter
 
ScarabChris's Avatar
 
Join Date: Jul 2005
Location: Dania Beach, FL
Posts: 28,075
Default

Originally Posted by cbraz82 View Post
I have two 900/5's, 4 6.5's on each amp. Each amp also has 1 JL M10. Sounds great, you could buy one more 900/5, 4 more speakers and split your subs between the two amps. I started out like yours is now, added the amp, and got much more bass once each sub had 500 watts. That totals out at 8 speakers and 2 subs. That way your amps aren't working very hard to push the subs. FYI: I also have the Fusion IP600.
That might be a little overkill for me these days. I'm 38 now and usually have kids on board. Back when I was in my 20's I had massive systems in my cars and boats.

The system sounds amazing now. The subs are in the sides of the console so the whole console acts as an enclosure. The bass is extremely boomy. The boat is a 2 piece so event the 7.7's in the gunwales are somewhat boomy and crisp.

Right behind these rod boxes is where I want to put the 3rd pair of speakers.
ScarabChris is offline  
Old 08-10-2012, 12:05 PM
  #12  
Senior Member
 
Join Date: May 2012
Location: St. Augustine, FL
Posts: 739
Default

Chris - I've pretty much got the same setup (different style boat) and so I run my cabin speakers off the Fusion. It puts out PLENTY of power to the cabin speakers.

Oh - BTW - remember my email the other day. Voltage is the same side on both sides on the strip lights. Last night wife commented - why are those lights flickering.
MackSea70 is offline  
Old 08-10-2012, 12:46 PM
  #13  
Senior MemberCaptains Club Member
 
Join Date: Dec 2007
Location: PBG, FL
Posts: 8,933
Default

no offense but 500 watts to a sub will fry them. trust me i know ive done it....twice. set the amp up correctly itll push 550 to the sub channel which is 275 each and if you look at the max wattage the subs take it is 250. anymore and you can fry the coils. show me your voltage that each sub is getting 500 watts and ill take it back. i have 3 mhd 900s. run 4 7s off each and 2 subs.

Originally Posted by cbraz82 View Post
I have two 900/5's, 4 6.5's on each amp. Each amp also has 1 JL M10. Sounds great, you could buy one more 900/5, 4 more speakers and split your subs between the two amps. I started out like yours is now, added the amp, and got much more bass once each sub had 500 watts. That totals out at 8 speakers and 2 subs. That way your amps aren't working very hard to push the subs. FYI: I also have the Fusion IP600.
bradv is offline  
Old 08-10-2012, 12:47 PM
  #14  
Senior MemberCaptains Club Member
Thread Starter
 
ScarabChris's Avatar
 
Join Date: Jul 2005
Location: Dania Beach, FL
Posts: 28,075
Default

Originally Posted by MackSea70 View Post
Chris - I've pretty much got the same setup (different style boat) and so I run my cabin speakers off the Fusion. It puts out PLENTY of power to the cabin speakers.

Oh - BTW - remember my email the other day. Voltage is the same side on both sides on the strip lights. Last night wife commented - why are those lights flickering.
Yeah I think I might get these for the back instead of the components just for an easier install and run the center set from the Fusion and these new ones on the amp channel that the now back speakers (center) are on.

http://www.jlaudio.com/m770-ccx-cg-w...-systems-91784

Shoot me an email on the business email and I'll get you squared away. I'll just send you some new strips. Maybe one in the string is bad causing the rest to flicker. But I'll send you enough to make the entire run at no charge.
ScarabChris is offline  
Old 08-10-2012, 12:51 PM
  #15  
Senior Member
 
Join Date: Jul 2004
Location: S Fla
Posts: 23,400
Default

I have said for years that the aft speakers are where the second set should go....it adds so much depth.....
Glen E is offline  
Old 08-10-2012, 03:00 PM
  #16  
Senior MemberCaptains Club Member
Thread Starter
 
ScarabChris's Avatar
 
Join Date: Jul 2005
Location: Dania Beach, FL
Posts: 28,075
Default

I was also thinking maybe I can put them in the lean post facing back. Just not sure they will fit. There is a 55 gallon live well and tackle drawers on each side. But honestly I like a more uniform look so I will likely stay with the original plan and put them in the gunwales behind the rod boxes.

I already ordered a pair of M770-CCX-CG from Jim at BOE.

I think I am going to buy a 6.25" hole saw for this one. That is a tight spot and a jig saw will be a PIA!

ScarabChris is offline  
Old 08-10-2012, 05:37 PM
  #17  
Senior MemberCaptains Club Member
 
Join Date: Dec 2007
Location: PBG, FL
Posts: 8,933
Default

Dangerous proposition. I have u have real strong wrist
bradv is offline  
Old 08-10-2012, 07:06 PM
  #18  
Senior MemberCaptains Club Member
Thread Starter
 
ScarabChris's Avatar
 
Join Date: Jul 2005
Location: Dania Beach, FL
Posts: 28,075
Default

Originally Posted by bradv View Post
Dangerous proposition. I have u have real strong wrist
You mean the big hole saw? The right tool for the right job. I have a good drill with a clutch and a handle bar. If the hole saw locks in the fiberglass the clutch disengages the motor and the handle bar gives you more control. I cut a 6" hole in 1/2" thick aluminum the same way. No problemo.
ScarabChris is offline  
Old 08-11-2012, 02:39 AM
  #19  
Senior MemberCaptains Club Member
 
Join Date: Dec 2007
Location: PBG, FL
Posts: 8,933
Default

Sweet. Mine keeps going and almost snaps ur wrist. I use a rotozip or a tukey cutter looking tool with a jigsaw blade for my speaker holes.
bradv is offline  
Old 08-14-2012, 08:08 AM
  #20  
Admirals Club Admiral's Club Member
 
Join Date: Jan 2011
Location: Birmingham/Orange Beach
Posts: 214
Default Speaker Placement

When I was running both subs off the one amp at very loud volumes the amps would over heat and cut off, I have the sub gain relatively low now and can play the speakers very loudly with out the amps cutting out. I hid Box speakers under the sides of the boat in the rear and have been very pleased with them.
Attached Images      
cbraz82 is offline  

Thread Tools
Search this Thread