audio experts please help
 

I just picked up a alpine head unit and a pdx -f4 4 channel amp. I am going to power 4 6.5" speakers with this set up. Then I remembered that I have 2 bose 6" subwoofers sitting in my basement collecting dust. Can I connect these 2 directly to the head unit and power them off the internal amplifier.

I would think the head unit will not have enough power to power the subs. A better way may be to connect the subs to the amp and the 6.5 to the head unit.

you definately cannot do that, you must purchase an amplifier for the subs

you will be very light on output power to drive a pair of 6" woofers ( I don't think you can call a 6" speaker a "sub woofer" :) )

Bose can, its all in the marketing !!! :lolhit:

Sometimes they do.....I know my 91 vette has Bose speakers and each one has it's own amp built in. Makes for a pain to change.

If it were me I would leave the Bose speakers collecting dust in your basement. They are not very good speakers, and are not designed to work in an open air environment. Usually these speakers are in a plastic bandpass box which gives it the boom of a slightly bigger speaker but only at a certain frequency. However, the sound quality is not there. I have 2 10" boston acoustic G5's in my boat and I'm quite happy with it but there also getting fed 600 watts RMS. Save up some money and do it right.

Bose does some amazing things with enclosures and small "subs", however a 6" sub is not going to get you far in a boat, even with a band pass set up like bose uses for enclosures. These "subs" are made for a small car, or the corner of a living room using well thought out enclosures.

My suggestion- quality audio components are relatively inexpensive today, get your set a quality pair of 10-12" subs and a good sub amp with a low pass crossover. When installing the subs under a seat you still want to build an enclosure under the seat, for sealed or ported subs.

Sealed sub boxes give tighter bass but require more power.

Ported subs make looser booming bass but are more efficient

I have seen (and fixed) a lot of subs that are just installed in the kick wall under the seat without an enclosure, the bass you give up with a setup like this is amazing, not to mention the speakers will last longer with the right enclosure. It is very simple to build a good box under the seat, build the sides and the top and seal the corners, a top is a must!

Subs make the best bass when the air from the front of the speaker is seperated from the air on the back of the speaker, or the air from one side is allowed out with a tuned port.

Many people think "free air" subs make bass just sitting there, not the case. The air from the front must be sealed from the back for max performance, free air just means the back "enclosure" can be any size.

[QUOTE=endeavour32;3259457]If it were me I would leave the Bose speakers collecting dust in your basement. QUOTE]

I agree!! You can get a decent pair of kicker, alpine, etc subs that will blow away anything you can do with the bose ones. I installed 10" alpine marine free air subs under my back seat this summer. They sound good, even with a somewhat small amp driving them. You can probably get a pair of them, with a decent amp for under 250 bucks.

if your Alpine head unit is the marine radio, id should be a digital. Alpine makes very nice marine ampa. I have personaly installed 4 amps in a customer's boat, dialed it all in and it sounded so good that you had to get out of the boat is so loud. each sub had its own amp. Cockpit speakers had their own amp and forward cabin had its own amp. also used alpines marine speakers as well and great sounds.

BTW way, the pdx-4 is not a marine amp and if used in the saltwaterenviroment , it will not last.

The Alpine digital thing is just marketing b.s. All the signals that come out of an alpine or any "mobile" stereo are analog. If it was digital you would either use a fiber optic cable "toslink" or a single digital 75 ohm "rca" cable.

The Alpine amps are class D analog, put a digital signal to a speaker and you'll get no output. It must be analog. There are some digtial paths in some of this equipment most likely only in the head unit but any CD player is going to have a digital signal path until it goes to the D/A converter. Other than that its a waste, to convert from analog to digital and then back to analog. The more converting the lower quality the sound will be.

just get a good 6 channel amp with a 2 channel low crossover and be done with, run anything you want.

well i have been thinkin about it and im gonna scrap the bose idea. What im thinkin about is buying 4 alpine 7" speakers to hook up to the amp and that will be my system. Was lookin at the JL speakers but man they are double the cost of the alpines

I did the 7" alpines. bought them from sonix electronics. great prices and fast shipping.

How many speakers are you going to run off the pdx amp??? You could run 4 of speakers off of 2 channels on the amp and then run the woofers off of the other 2 channels.

The amp is fine at 2 ohms and it will be fine for marine use.

im thinkin of runnin 4 alpine 7" speakers off of the pdx amp. Ive mounted the amp in the cabin not worried about water

Do as Griff said and then get a pair of Boston Acoustic G3 10" subs, you can run these in either 2 ohm stereo or 4 ohm mono.... I promise you there better than Alpine subs and equal to JL Audio. IMO Alpine makes great head units, pretty good amps, but there speakers are just OK when compared to other high end stuff. If they sound good to you thats all that matters but I really think you would like the Boston Acoustic stuff better.

http://www.sonicelectronix.com/item_...mpaign=froogle

As long as you don't get the Boston Acoustic G3 10" subs wet. They are not marine speakers. I put non-marine woofers in a boat a long time ago. They did not last. The humidity killed them in 3 years.

I would just run them off the amp that you have then.
If you want to add subs later, then get a PDX sub amp.

I have 2 Alpine 10" Marine subs and they sound just as good as the JL marine subs for less than half the cost. I also run 8 DC Gold speakers off of a PDX 4.150.

They are a poly coned. Yes a paper cone won't last but who makes a paper coned speaker any more. I've been using mine for two years and no problems... IMO most marine subs are just cheap auto subs painted white at twice the price or more. A copper voice coil is a copper voice coil, poly cone is a poly cone.

Most any auto speaker is made to handle high humidity and door speaker are made to get wet. I just never really got sucked into the whole marine audio thing, IMO is mostly just marketing.

I agree, except for head units. they have remote transmitter inputs and have better internal construction for vibration

Agree- Plus with the sony marine head units you can use the commander controller which is a fantastic remote.

Im just getting ready to start my new stereo install. I went with all Alpine stuff.

Head unit - iDA-X100M
Speakers 4 pr - SPR-M700 7"
Subs 2 - SWR-M100 10"
1 amp for subs -PDX-1.600M
2 amps for speakers - PDX-4.100M

Very similar package to what I have. I'm running all 8 of my DC gold speakers off of one PDX 4.150 and running the a PDX 4.100 bridged to power my subs. I already had the 4.100 or I would have gone with the 1.600. It will hurt my ears if I'm in the boat and crank it all the way up.

well ive got the system installed alpine head unit, pdx-4 amp and 4 jl 770's. Sounds good but I get a popping sound from the speakers when I turn it up real loud. almost sounds like a balloon popping. Im guessing that means Im giving the speakers a little more bass then they can handle, for thats when it happens is on the heavy bass hits. Im a little worried about it. Now I wish I would have bought the 5 channel amp and added a sub it would really round out the system. Still tossing around the idea,maybe another amp and 2 subs

Yep, sounds like too much power for the speakers to handle.

Hey Griff, How many batteries do you have running your system? I was figuring 2. I also have a dual battery charging module from Atkinson Electronincs I planned on putting on it.

Are your batteries completly charged? I sometimes get similar sound when they no longer are putting out 12 amps.

I run all of my stereo off of one Interstate group 29M deep cycle battery. The head unit is wired into a switch at the helm, but everything else is wired to the 29M. The head unit really doesn't pull hardly any power since the internal amp is switched to off. I have 8 speakers, 2 subs, a PDX 4.150 and PDX 4.100 bridged. I've never run the battery down so low that the stereo would cut out. I've run it at 3/4 volume 3-4 hours.
I have 2 other group 24 batteries for starting the engines.

How does your 29M battery charge? Do you have it connected your alternator or just rely on a onboard charging system? Im just starting to learn how this stuff goes, so sorry for the lame questions.

I have 2 Perko switches. #1 on each switch is for the starting battery on each engine. #2 on both switches goes to the deep cycle. That way I can charge the deep cycle off either engine. I never put both switches on #2 when running. If I switch both switches to ALL, as long as I have one good battery, I can start both engines. I do not have an on board charger. A few times when I have run the stereo hard for a long time I will charge the deep cycle with a 10 amp charger overnight.

Thanks Griff, your help is always appreciated.

Sorry to hijack the thread.

latest update on the system. Just purchased an alpine pdx-m6 amp and a jl 10" sub to mount under the bed in the cuddy. System needed some bass. hopefully this will do it