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Catalina/Capri 25/250 Sailor's Forums

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8 ohm Speakers w/o External Amp

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Justin
Admiral

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502 Posts

Initially Posted - 02/14/2006 : 08:56:39

I did some searches but didn't find what I was looking for. I'm planning to buy these [url="http://www.crutchfield.com/S-NunmzULrmmb/cgi-bin/prodview.asp?i=107ATR45W&s=0&cc=01"]Polk Atrium 45 outdoor speakers[/url]. I plan to mount them on the cabin forward bulkhead. I was planning to connect them to a Kenwood car receiver, but then I realized the Polks are 8 ohm speakers. This would mean that the 22 RMS watts internal amp is rated at 4 ohms and so at 8 ohms, the receiver would only be able to pump out about 10-11 watts. Crutchfield is recommending an external amplifier to power 8 ohm speakers. This adds to the energy consumption, complication, and cost. I have two batteries and plan to get a solar panel, 20 watt I think, so I'm trying to figure out if an amp will be needed and okay. Those of you that use outdoor speakers, are your's rated at 8 ohms and how are they when ran straight off the receiver? I appreciate the input.

Thanks,

Justin
Previous Owner of Sapphire Breeze - 1982 Catalina 25 SK/SR
My sail blog site: https://reveriesailing.com/

Edited by - Justin on 02/14/2006 09:01:25

Sloop Smitten
Master Marine Consultant

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USA
1181 Posts

Response Posted - 02/14/2006 : 09:24:09

Justin,
The speakers will handle much more power then your receiver can push. If you mount them in the cabin with the intention of listening to them while in the cockpit (possibly with the engine running) you will distort the output before you reach the proper volume. Better to get 4 speakers, 2 for the cabin and 2 for the cockpit. Those speakers sound like overkill for your receiver. By the way, just about any outdoor speaker will work in the cabin. Marine grade can be reserved for the cockpit. You are right, 8 ohm speakers will diminish the power output. Just my opinions, others may disagree.

Edited by - on

Frank Hopper
Past Commodore

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Pitcairn Island
6776 Posts

Response Posted - 02/14/2006 : 09:44:42

Speakers are the weakest point in a system, they are subject to more variation than any other component. Because of the environment, I use modest two way speakers from radio shack (RCA) on the inside. I have used them in two boats now and have been very pleased. I know they are not audiophile quality but neither is the environment. If you want high fidelity then keep a set of nice headphones on board. I think you will be surprised at how satisfied you are with more modest speakers. PolyPlanar are a nice quality marine speaker, the advantage to marine speakers is they take marine mounting issues into consideration in their designs. By the way the polks look fine to me, I wouldn't worry about the impeadance. Remember, a 3db increase in sound level from a speaker requires a doubling of the output power of the amplifier. Therefore you are listening to a miniscule amount of power most of the time anyway.

Edited by - Frank Hopper on 02/14/2006 09:57:08

Ericson33
Admiral

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USA
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Response Posted - 02/14/2006 : 10:26:26

I have spent a lot of money in the past for Car Audio Equipment, After I sold my last car I tore all of that stuff out and put it under our bed. Good equipment comes at a high price, If you spend a good amount of money on the speakers then in turn you will need to spend the money on a good head unit and amp. My 2 cents are that while an amp would be nice in a boat its the wrong place to have one, along with pricy equipment. It is going to be used a small amount of the time, and it will be drowned out by the Moter as well as the crew. I myself have spent the money on a good quality system, but its in the garage right now waiting to be hooked up. Our solution has been our kids boom box, while this might not be the quality install that you are looking for, it is removable (theft) it is portable (cabin to cockpit) and its light weight, and it does not require you to drill any holes in the boat, or string wires across the boat. Yes, I know YOU WANT THE SYSTEM INSTALLED, I would suggest just what Frank above stated, Get somthing that if it breaks, or gets wet its not going to kill the bank. I am also a fan of Radio Shack Equipment. They sell brand named stuff, it just has their logo on it. You also might want to split the cost and get a newer head unit that does 50x4 and bridge the 4 chanels, this is my next goal with the equipment I have for the boat.

Now, Really I would love to put the stuff I had for the car in the boat, I had 3 amps One 2 Channel 400w bridged to 2 12" subs, another 4 channel 220w that ran the Kicker Seperates in the front doors 6" sub 1" tweeter, and another 2 channel 200w that ran a pair of 6x9 Cerwin Vega. all of this ran to a Mini Disk Recorder that you could record live off the air in your car. I would love to trow this stuff in the boat and take her out for a couple of races. Imagine the subs booming off of a 25' fiberglass shell, Priceless

Edited by - on

Justin
Admiral

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502 Posts

Response Posted - 02/14/2006 : 11:37:05

I re-read what I posted and I don't think it came across the way I meant. My main concern is if the receiver will be powerfull enough to power the 8 ohm speakers mounted in the cabin and still be heard in the cockpit while under sail. I would prefer not to have to use an amp. Frank, do you know if your's are 8 ohm rated? I now remember hearing about that doubling the power for 3db a while ago, thanks for mentioning it. I shouldn't hear much of a difference then. I just hope that ~11 watts rms will be enough for casual listening, I don't intend to have music blasting. Where you mounted your speakers is where I'm planning as well. I'm some what of an audiophile and I know the boat isn't the greatest environment, but I'm a fan of Polk. I've used them in my past 2 car stereo systems and then I have a nice Athena system at my place. From what I read in reviews and tested in stores, I found these Atrium 45s to be excellent, especially for the cost and size. They are even better than the way over rated/price Bose speakers. Being $50 off and having credit at Crutchfield makes them an even better deal. I plan to eventually put some in the cockpit as well. I'm thinking the seat back near the transom. Since the tiller is there, that part of the bench will not be blocked much.

Oh yeah, Chris, if you could put your old stereo into the boat, that would be awesome! I wonder how quick it would drain your batteries though. I wonder if boats nearby would actually hear the music through their hull. I remember being on sailboats in the past and you'd hear the engines of powerboats by the underwater soundwaves reverberating against the hull.

Edited by - Justin on 02/14/2006 11:40:11

djn
Master Marine Consultant

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USA
1561 Posts

Response Posted - 02/14/2006 : 12:17:19

Hi Justin, here is my home system, but I don't think it will fit on the boat. The best thing you can do is set it up and give it a listen. It might work, or not. The problem might come if you get 4ohm exterior speakers for the cockpit. they will not match the cabin speakers volume do to the impedance mismatch. Good luck.

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Justin
Admiral

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502 Posts

Response Posted - 02/14/2006 : 12:25:12

WOW!!! Dennis, those are some HUGE speakers! You need a bigger TV to match them lol. What kind are they? About mixing the impedance ratings, have 4 ohm rated outside and 8 inside doesn't hurt the amp does it? I don't think it does, but wanted to get another opinion. I figured I'd use the fade control on the receiver to adjust different volume levels if needed. Also, say for example we're all hanging out in the cabin and don't want to bother people in a crowded anchorage as much, I might turn down/off the exterior speakers.

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Frank Hopper
Past Commodore

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Pitcairn Island
6776 Posts

Response Posted - 02/14/2006 : 13:13:43

I think mine are 8 ohm. Dennis that is one acousticly bright room for a horn based system. How often do your ears bleed? You might want to hang some rugs, remember anechoic is the goal.

Back in the day my favorite test cut was Tank by Emerson Lake and Palmer, bad speakers would start doubling, (meeting them selves coming and going) Bose are crap and always have been, they would double early. Another great cut is Jump into the Fire by Nilsson, arguably the best base riff ever.

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djn
Master Marine Consultant

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USA
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Response Posted - 02/14/2006 : 14:07:22

Hi Frank, you are right about the room being bright. What you don't see in that pic is the 20 foot wall of sliding glass doors down the left side of the room. I also like both those cuts. Another great bass rif is the one in the middle of Graceland by Paul Simon. I just ordered a set of components to build a pair of Edgarhorns. Those should sound good. Cheers.

Edited by - on

Justin
Admiral

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502 Posts

Response Posted - 02/16/2006 : 14:33:11

One other question about installing the speakers. What kind of wire did you use? I'm thinking of using some marine grade duplex 16 gauge wire.

Edited by - Justin on 02/16/2006 14:34:17

djn
Master Marine Consultant

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Response Posted - 02/16/2006 : 15:56:16

That would work just fine Justin. As long as it is marine grade. Cheers and happy listening.

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chriszzz
Deckhand

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Response Posted - 02/16/2006 : 17:50:39

After much careful thought, I've decided to go with a boombox. I don't want to muck up the classy interior with permanent speakers. I'm going to set up one 12V outside and one inside. The boombox can play MP3 CD (10 albums/disk) and had an ipod input. $100.

http://www.amazon.com/gp/product/B00083CZH0/ref=pd_ecc_rvi_4/103-1310670-8984605?%5Fencoding=UTF8
Sony White Psyc CD Boombox with ATRAC MP3 Player - ZSSN10PSWHI

Make sure you get a unit with an ipod input. And they make special marine heads. A car stereo will rust quicker.

Edited by - chriszzz on 02/17/2006 10:05:49

Frank Hopper
Past Commodore

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Pitcairn Island
6776 Posts

Response Posted - 02/16/2006 : 18:12:15

Most of us did that for a while too. At some point you will decide to move on, until then keep the boat flat and enjoy the tunes.

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frog0911
Master Marine Consultant

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USA
1349 Posts

Response Posted - 02/16/2006 : 19:01:40

Make sure you get a step down transformer. If you plug 12V into your boombox's 9V system you will blow lots of tiny board parts and void your warranty.

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dlucier
Master Marine Consultant

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Virgin Islands (United Kingdom)
7583 Posts

Response Posted - 02/16/2006 : 19:40:24

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by fhopper@mac.com
 Most of us did that for a while too. At some point you will decide to move on, until then keep the boat flat and enjoy the tunes.<hr height="1" noshade id="quote"></blockquote id="quote">

Well, that's not too condescending!

Chris, I'm one of those who obviously hasn't moved on and use a boombox for tunes. I've been doing so for years and my boat definitely does not remain flat.

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Frank Hopper
Past Commodore

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Pitcairn Island
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Response Posted - 02/16/2006 : 22:23:07

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by dlucier
 <blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by fhopper@mac.com
 Most of us did that for a while too. At some point you will decide to move on, until then keep the boat flat and enjoy the tunes.<hr height="1" noshade id="quote"></blockquote id="quote">

Well, that's not too condescending!

<hr height="1" noshade id="quote"></blockquote id="quote">

I did not mean it to be condescending at all, more of support for his decision because so many people do that for a while. I used one on my Spirit 23 and Merit but once you have a cruiser it is hard not to see the advantages to an installed system. It is of course up to the desires of the user. Four widely separated speakers playing softly make beautiful music for everyone to hear at volumes that do not drown people out, (boom boxes tend to give loud music in one place or music too quiet to hear all over the boat), they are weather proof, do not get damaged as easily, and are easier to integrate with other devices; that is why I value an installed system. I hope it goes without saying that I value a beautiful interior and see no conflict between a nicely installed system and a beautiful boat. But hey, that's just me.
You go Chris, it looks like you found a very cool boombox.

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chriszzz
Deckhand

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17 Posts

Response Posted - 02/17/2006 : 10:15:49

:)

True, I went back and forth with the decision. I will have to wire the +12V into
the boombox battery compartment, since there's no "9V/12V" input, just AC, so it's going
to be a little project in itself.

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