Off Season Stereo Build

[NautiGirl]

My 2 cents.
I would add another amp and leave the rest of your system a lone, assuming your happy with it.I would not run less than 100 watts to your tower speakers.

Tend to agree the M200/2 is the cleanest option. Unless you start bridging channels almost all JL M series Marine Amp's output 75W per channel at 4Ω. The only real option, other than moving up to the MHD line of amps, to get over 75W a channel is to buy a four channel amp and bridge it down to two channels but that gets you to 200W at 4Ω which as I stated is a lot for the MX voice coil to handle.

People get caught up in amp power ratings, but really it requires a huge change in amp power to equal a perceived change in loudness from the speakers. Doubling amp power results in 3db change in perceived volume, which is barely audible by the human ear. It takes a 10x increase in power to get a 10db increase in loudness which sounds "twice as loud" to most people. 75 vs 100 watts difference isn't a huge deal. If PuttPutts is cool /w the performance of his inboat speakers I would just buy a M200/2 and run the towers off that.

On the other hand if you really wanted to get to exactly the maximum recommended amp power for the 7.7Mx's you could buy a M400/4 and bridge it to two channels which would be 200W to each. You could then set the Gain's on the amp so that they only send 150W to the speakers. The amp wouldn't be producing the full power it was capable of at 150W but it would protect the voice coils in the speakers from overheating.

I was going to review setting the gain on an amp when we did ours. The correct way to do it is by playing a test tone while measuring amp power output w/ a multimeter. The voltage measurements at the speaker outputs should equal SQRT((Watts * Ohms)). So in this case SQRT((150*4)) or 24.49 volts at the amp output. If you wanted to run the amp at the full 200 watts you would turn the gain up until you got 28.28v.

JL has a really good article on how to set the gain on an amplifier on their site: https://jlaudio.zendesk.com/hc/en-us/ar ... ting-Guide

[Bfun220]

I have always used 75%-150% to size my amps. It's not just the loudness of the speaker. For a 150 watt rated speaker that's 112 - 225 watts. If your going to be playing these speakers loud I'd want the reserve power of a larger amp. If your listening at lower levels, then I won't waste the money on a larger amp.

Good info on setting the gain.

[NautiGirl]

I have always used 75%-150% to size my amps. It's not just the loudness of the speaker. For a 150 watt rated speaker that's 112 - 225 watts. If your going to be playing these speakers loud I'd want the reserve power of a larger amp. If your listening at lower levels, then I won't waste the money on a larger amp.

Good info on setting the gain.

Yup - we are on the same page. The JL MX series is rated at 70 Watts continuous so JL is using something similar to your 75% - 150% when they recommend an amp with a power output of 25 - 150 watts. Think that was the confusion, the speakers are rated at 70W not 150W RMS.

So if you want to stick /w JL Amps your options are to buy something that will output 75w in a two channel config or buy a four channel amp bridge it and get 200watts. Kinda sucks they dont have something around 100 or 125watts, but those are the options.

Keep in mind those numbers are w/ the amp getting 14.4 volts which almost never happens. Not to confuse the issue but JL publishes numbers at a more realisitc 12.6v. They are 60watts or 180 watts bridged at 4ohm.

[Bfun220]

Yup, same page. I was thinking the speakers were rated 150 watts.
Good reminder about almost never going to see those numbers at the sandbar running on 12.6v instead of 14.4v

[MnLakeBum]

I have always used 75%-150% to size my amps. It's not just the loudness of the speaker. For a 150 watt rated speaker that's 112 - 225 watts. If your going to be playing these speakers loud I'd want the reserve power of a larger amp. If your listening at lower levels, then I won't waste the money on a larger amp.

Good info on setting the gain.

Yup - we are on the same page. The JL MX series is rated at 70 Watts continuous so JL is using something similar to your 75% - 150% when they recommend an amp with a power output of 25 - 150 watts. Think that was the confusion, the speakers are rated at 70W not 150W RMS.

So if you want to stick /w JL Amps your options are to buy something that will output 75w in a two channel config or buy a four channel amp bridge it and get 200watts. Kinda sucks they dont have something around 100 or 125watts, but those are the options.

Keep in mind those numbers are w/ the amp getting 14.4 volts which almost never happens. Not to confuse the issue but JL publishes numbers at a more realisitc 12.6v. They are 60watts or 180 watts bridged at 4ohm.

I’ll throw in my two cents having sold stereo equipment for a decade after I graduated from college and dabbled in the car stereo competitions back in the day. I’m guess you could say I’m a pseudo audiophile with a $2,600 pair of Magnepan’s on my main system driven by a $2,500 preamp and $3,000 amp. Since the late 1980’s I’ve been installing separates from companies like Boston Acoutics or Focal in my cars. BTW, if you don’t want to drop $2,000 on a pair of Focal Utopias for your car or boat you can get similar sound from a little known company called DLS for about $500.

It’s important to remember that wattage ratings are not only exaggerated but have nothing to do with sound quality. 50 watts of clean power is a lot of power - enough to driver quality boat speakers to the point where you won’t be able to talk to anyone in the boat and will be heard miles away. JL makes some great stuff but ignore the wattage ratings. The more expensive JL’s will sound better than their cheaper ones. Getting a good quality amp is important as well and again let price be your guide. The better amps will look less powerful on paper but the will sound better and also be more expensive. Good clean bass in a boat is tough because you are outside rather the enclosure of your car or living room. It takes a ton of power and a very large, expensive driver to compress even a large living room - my home sub weighs over 100 lbs. The challenge in a boat is much greater and IMO it takes at least double the money on a sub/amp for a boat for good bass compared to a car. I don’t do it in my R5 because all it does is annoy other boaters, neighbors and makes it more likely that my college age son and daughter will be annoying with some of their crappy music!

I will be installing some new speakers and some 1992 Sony ES amps in our R5 next year that are rated at 60 watts per channel RMS. I bench tested them at 14.4 volts back when they were new and they delivered 283 watts RMS at 4 ohms and double that at 2 ohms. If you want that type of clean power now you will need to spend a lot of money. I’m still amazed that these amps have survived being installed in about a dozen different vehicles.

[MnLakeBum]

Another thing I forgot to mention is getting a proper ground for your amps in a boat can be a challenge. I prefer to have a professional installer do it rather than do it myself.

[NautiGirl]

I have always used 75%-150% to size my amps. It's not just the loudness of the speaker. For a 150 watt rated speaker that's 112 - 225 watts. If your going to be playing these speakers loud I'd want the reserve power of a larger amp. If your listening at lower levels, then I won't waste the money on a larger amp.

Good info on setting the gain.

Yup - we are on the same page. The JL MX series is rated at 70 Watts continuous so JL is using something similar to your 75% - 150% when they recommend an amp with a power output of 25 - 150 watts. Think that was the confusion, the speakers are rated at 70W not 150W RMS.

So if you want to stick /w JL Amps your options are to buy something that will output 75w in a two channel config or buy a four channel amp bridge it and get 200watts. Kinda sucks they dont have something around 100 or 125watts, but those are the options.

Keep in mind those numbers are w/ the amp getting 14.4 volts which almost never happens. Not to confuse the issue but JL publishes numbers at a more realisitc 12.6v. They are 60watts or 180 watts bridged at 4ohm.

I’ll throw in my two cents having sold stereo equipment for a decade after I graduated from college and dabbled in the car stereo competitions back in the day. I’m guess you could say I’m a pseudo audiophile with a $2,600 pair of Magnepan’s on my main system driven by a $2,500 preamp and $3,000 amp. Since the late 1980’s I’ve been installing separates from companies like Boston Acoutics or Focal in my cars. BTW, if you don’t want to drop $2,000 on a pair of Focal Utopias for your car or boat you can get similar sound from a little known company called DLS for about $500.

Nice Humble Brag.

The better amps will look less powerful on paper but the will sound better and also be more expensive.

Can you elaborate a bit more on this? At least in their marine line JL's more expensive MHD Amps all come with an associated higher power ratings. Additionally, they also make their rated power down to 12.6v, presumably due to their regulated power supply.

I will be installing some new speakers and some 1992 Sony ES amps in our R5 next year that are rated at 60 watts per channel RMS. I bench tested them at 14.4 volts back when they were new and they delivered 283 watts RMS at 4 ohms and double that at 2 ohms.

I'm assuming thats 283 watts across all four channels so about 70 per channel?

[MnLakeBum]

Yup - we are on the same page. The JL MX series is rated at 70 Watts continuous so JL is using something similar to your 75% - 150% when they recommend an amp with a power output of 25 - 150 watts. Think that was the confusion, the speakers are rated at 70W not 150W RMS.

So if you want to stick /w JL Amps your options are to buy something that will output 75w in a two channel config or buy a four channel amp bridge it and get 200watts. Kinda sucks they dont have something around 100 or 125watts, but those are the options.

Keep in mind those numbers are w/ the amp getting 14.4 volts which almost never happens. Not to confuse the issue but JL publishes numbers at a more realisitc 12.6v. They are 60watts or 180 watts bridged at 4ohm.

I’ll throw in my two cents having sold stereo equipment for a decade after I graduated from college and dabbled in the car stereo competitions back in the day. I’m guess you could say I’m a pseudo audiophile with a $2,600 pair of Magnepan’s on my main system driven by a $2,500 preamp and $3,000 amp. Since the late 1980’s I’ve been installing separates from companies like Boston Acoutics or Focal in my cars. BTW, if you don’t want to drop $2,000 on a pair of Focal Utopias for your car or boat you can get similar sound from a little known company called DLS for about $500.

Nice Humble Brag.

The better amps will look less powerful on paper but the will sound better and also be more expensive.

Can you elaborate a bit more on this? At least in their marine line JL's more expensive MHD Amps all come with an associated higher power ratings. Additionally, they also make their rated power down to 12.6v, presumably due to their regulated power supply.

I will be installing some new speakers and some 1992 Sony ES amps in our R5 next year that are rated at 60 watts per channel RMS. I bench tested them at 14.4 volts back when they were new and they delivered 283 watts RMS at 4 ohms and double that at 2 ohms.

I'm assuming thats 283 watts across all four channels so about 70 per channel?

It’s a 2 channel amp and that bench test was in stereo mode with both channel driven to clipping, which was at 283 watts per channel @ 14.4 volts. If memory serves me right the larger 100 watt rated amp that runs my sub clipped at 650 watts into 2 ohms which is about the load my dual 4 ohm voice coil sub puts on it.

As far as regulated vs unregulated power supply, both work well but I haven’t kept up on the latest 12volt stereo amps as mine have been working well for so long. It’s very likely that the newer high end amps don’t underrate their power like many of the old ones did. These Sony Mobile ES amps I’m running were built in Japan before Sony moved all their manufacturing to China and Indonesia. I remember my co-worker who I still hang out with buying their top of the line CD player that was $2,000 in 1988. To put that in perspective, the brand new Honda Accord it went into was only $10,800. Back then I had an Audi Coupe GT that was 6 years old that I paid $3,500 for and I think I had about $10,500 worth of audio gear installed in it. Young and dumb!! Maybe I should have bought $10k worth of Best Buy stock, where I worked, instead - it was 26 cents a share when I started in 1988 and around $25 a decade later:shock:

BTW, Most newer boats don’t have any trouble deiivering at least 13.5 volts to the amps. My voltmeter on my both my Marker One and R5 both rarely read under that when underway with all the electronics running.

[MnLakeBum]

1

[ajcampen]

If you were going to replace head unit and the remotes, what would you do? I have Sony head unit and two hard wired remotes. The hard wired remotes have a cut out that is 3.25 inch wide....which is sadly huge. I am going to buy a new ignition panel in my dash (waiting on a quote, and some type of a cover for the transom.

I think I want a fusion head unit. They also offer non-hardwired remotes over Bluetooth for $50 each.

[NautiGirl]

If you were going to replace head unit and the remotes, what would you do? I have Sony head unit and two hard wired remotes. The hard wired remotes have a cut out that is 3.25 inch wide....which is sadly huge. I am going to buy a new ignition panel in my dash (waiting on a quote, and some type of a cover for the transom.

I think I want a fusion head unit. They also offer non-hardwired remotes over Bluetooth for $50 each.

This one I can't help /w. When we replaced our head unit I put in a new Sony. I hate Sony, but the hardwired remote compatibility won.

All I really need the Head Unit for is to tell the amps to turn on and to connect our iPhone up, the Sony does that ok and has 3 preouts for the amps so I shouldn't complain I guess.

I haven't shopped it much but from what I saw on the factory tour the new Rockford Fosgate stuff is pretty nice. We are going to the boat show Thursday so I will have to report back what we find.

[Bfun220]

If you were going to replace head unit and the remotes, what would you do? I have Sony head unit and two hard wired remotes. The hard wired remotes have a cut out that is 3.25 inch wide....which is sadly huge. I am going to buy a new ignition panel in my dash (waiting on a quote, and some type of a cover for the transom.

I think I want a fusion head unit. They also offer non-hardwired remotes over Bluetooth for $50 each.

Are you sure you have 3.25 inch cut out ? Mine had like a 1 inch hole and 2 smaller (maybe 1/4 inch)mounting holes.

If the RF head unit would have fit in my factory location I would have gone with them and 2 wired remotes.

[ajcampen]

I’ll have to pull it out

[ajcampen]

I’ll have to pull it out and take a look. Did it look like this?

[Bfun220]

Sorry, I thought it was still the older style, Like this.
I'd still pull it and check.