Amps and Speakers and Such

[Zerbel04]

Yep I realize this topic has been brought up in other threads but after numerous google searches and a buncha reading I'm gonna do the lazy thing and ask anyway.

I've decided to install a Roswell Area 51 tower in the Sring with the "Full Load Package" which includes wiring to 2 R6 Roswell speakers. I currently have 2 speakers in my boat and am perfectly fine with their output............however with these 2 additional tower speakers I clearly will need an amplifier installed.

I don't know what the RMS is for my speakers nor do I know what the head unit pushes but I am assuming the factory speakers are 50W RMS and the head unit likely only pushes 12 to 15 RMS.

So can someone explain in plain English what would be required to get the proper sound out of the tower and in-boat speakers. How many channels (and what would the function of each channel be.....yes I'm that dumb in this area), where would the amp be best mounted, type of wiring, and any other helpful pointers? Is there a way to control the volume of the in-boat and tower speakers separately so I don't always have to be the obnoxious loud boat?

I really don't know a lot about this type of stuff but I'm the type of person that would rather know how it works and do it myself than simply give a wad of money to someone and trust their judgement.

 

[Silly Seville]

Re: Amps and Speakers and Such

Crutchfield is your friend.

 

[coolbri70]

Re: Amps and Speakers and Such

does the head unit have RCA type low level output? if not you will need a converter or an amp with high level inputs. is there a fader feature on the head unit? need more info on the head unit

 

[Zerbel04]

Re: Amps and Speakers and Such

Coolbri I don't have a lot of info on the head unit as my boat is tarped and covered with snow. I'll have to wait until I can get in there to get more details.

Maybe I should have saved this thread for Spring when I'll be actually doing the work. Was just hoping to have a solid understanding of the entire process and what is required so I can digest it over the winter and decide if it is within reach for a DIY.

 

[michealcroak]

Re: Amps and Speakers and Such

I'm sure Ur head unit can handle atleast 4 speakers as long as you are not using big subwoofers and u can use the head units fader from front to rear to switch from rack speaker
s to boat or both

 

[Zerbel04]

Re: Amps and Speakers and Such

Found a lil more info on the head unit. It is a Jensen MSR 3007. It does have a fader on it. The manual says the maximum output is 40W x 4. Does this mean that I am only using 2 of 4 available channels on the head unit since I only currently have 2 in-boat speakers. Still have no further specs on the existing in-boat speakers. Also I have 100% decided that I DO NOT want loud tower speakers that attempt to throw music back to the rider. I simply want decent quality sound in and around the boat for low cruising speeds and having a lil fun while parked.

Actually starting to consider scrapping the tower speakers altogether and just adding 2 more in-boat speakers in the bow and use the remaining 2 channels on the head unit to power them?

Also found a really neat option in the manual..........an RF remote control for the head unit. Now that is something that could be real handy. I constantly find myself reaching over to the head unit on the port side of the boat.

 

[skydiveD30571]

Re: Amps and Speakers and Such

Hey Zerbel,

That 40x4 rating is for max output, not RMS (root mean square) output. Almost every headunit nowadays has about the same output. Max 40-50 x 4 and RMS 15-20 x 4. Always go by rms output, its the real life power you can expect to see. Max output ratings are determined with voltage levels you will never see, with minimal to no losses which just isn't realistic. So plan on about 15 watts a channel with it.

Most people replace speakers (or add them in your case) and never think to use amps. Most people don't have much trouble except the occasional blowing of a speaker. Most aftermarket speakers you'd put in a car or boat will be RMS 40-100+ watts. You can tell that you are underpowering these speakers by alot with just the factory deck.

There's a really hot debate in the 12volt world about blowing speakers by underpowering them. It is now known that underpowering a speaker doesn't blow it. However, when you turn the radio up and you start to hear the distortion that inevitably happens, that is what kills speakers. This distortion, for the most part, comes from underpowering the speaker. So underpowering doesn't blow a speaker, but the results of pushing an underpowered speaker will do it. Amplifiers of course provide additional power to meet the demands of the speakers, and that distortion either happens at a much much higher volume level, or doesn't happen at all.

It's also important to remember that normal speakers aren't designed to play low frequency bass tones. A lot of people dont want to pay for a subwoofer so they jack the bass up on the headunit so that the normal speakers will do it. That's also really unhealthy for speakers and will shorten their life dramatically.

As time goes on, it is much healthier to adequately power speakers with an amplifier (assuming they aren't crap speakers rated at 15 watts a piece) but it isn't a requirement and many people do just fine without one. It's all your choice. Coming from the car audio world as an installer, I never saw a decent speaker, adequately powered, have a problem. Not a single one.

As for tower speakers, I highly recommend them even if you are not wanting horn loaded drivers to project sound to the rider. I'm sure you've noticed how quiet those 2 speakers in your boat get when you get in the water below the windshield of the boat. The sound is reflecting around the interior of the boat, and generally upwards out of it. With tower speakers, even just normal speakers like the ones in your boat, you will have much better sound around the boat while swimming. I added speakers made for projecting sound but I'm more of a fan of how they perform while we are hanging out and swimming.

 

[bruceb58]

Re: Amps and Speakers and Such

This distortion, for the most part, comes from underpowering the speaker.

The distortion occurs because the amplifier is running in its non-linear region or has reached an output that causes its output to be clipped. Has NOTHING to do with the rating of the speaker. If you have a channel of the stereo that is rated at 20W RMS output driving a 60W or 200W rated speaker, the same distortion will be present. The distortion/clipping itself will indeed cause more heating of the voice coil in the speaker but the term "under-powering" is incorrect. It is caused solely by the amplifier...not the speaker and its rating.

 

[skydiveD30571]

Re: Amps and Speakers and Such

I should have worded that differently. I tried summing it up in a non-technical way but didn't do such a good job.

I understand that operating an amplifier outside of it's linear region causes clipping, and that is essentially what distortion is. I also understand that this generally happens when a speaker is underpowered so the amplifier output is increased to compensate and now the amplifier is trying to operate beyond it's limits. I just summed it up by connecting "underpowered speaker" and "distortion" which wasn't necessarily correct. Thanks for clarifying.

 

[bruceb58]

Re: Amps and Speakers and Such

Running out of its linear region causes distortion. Depending on the amplifier, this can happen as low as 50% output. Past that, so that the signal reaches the power rails, causes clipping of the signal.

Basically, the OP can power his tower speakers off of his deck unit if he wants. If he has the max volume he wants to hear with no distortion, he is fine. However, if that volume causes distortion, he can add a power amplifier. If he is driving a speaker lower than its power rating, there is no way he can possibly blow the speaker.

 

[skydiveD30571]

Re: Amps and Speakers and Such

What internal differences in amplifiers cause them to begin clipping signal at different outputs?

 

[coolbri70]

Re: Amps and Speakers and Such

try adding the 2 speakers, then if you find yourself using more than 50 to 60 percent of your volume, you probably need an amp

 

[bruceb58]

Re: Amps and Speakers and Such

What internal differences in amplifiers cause them to begin clipping signal at different outputs?

Any stage of the amplifier where that particular stage reaches its saturation point will cause clipping. All designs are different.

 

[Zerbel04]

Re: Amps and Speakers and Such

Thanks guys for the great responses. This is exactly the information I was hoping to get and in plain language.

I can't find the head unit RMS rating anywhere. It's not in the manual and can't find it online. Would it be labelled on the unit anywhere? I think my next step will be to get some info on the existing 2 speakers and go from there.

 

[bruceb58]

Re: Amps and Speakers and Such

Would be good to find the model number.

What is the configuration of the speakers you have in the boat now? Do you have 2 or 4 currently? If you only have 2 you could put the 2 on your tower on the rear and the other 2 on the front and use your fader to control them that way. Hopefully your head unit has pre amp outputs for if/when you decide to ad an amp.

 

[skydiveD30571]

Re: Amps and Speakers and Such

Thanks guys for the great responses. This is exactly the information I was hoping to get and in plain language.

I can't find the head unit RMS rating anywhere. It's not in the manual and can't find it online. Would it be labelled on the unit anywhere? I think my next step will be to get some info on the existing 2 speakers and go from there.

I looked up your headunit also and couldn't find an rms rating. Since max is 40 watts I'd say a good guess would be about 15 watts rms. Give or take a couple.