School me on amps

I don't have any experience when it comes to audio systems so I was wondering if you guys can give me suggestions as far as what kind of amp (channels/watts) I would need.

I currently have the 4 in-boat speakers which are all 200 watts.
I also just bought a pair of tower speaker from my friend. They are 500 watts (http://www.amazon.com/dp/B0071HZJ56/..._M3T1_ST1_dp_1)

I eventually want to have a sub and add another pair of speakers along with some lights for the tower.

What kind of amp should I get (brands) that are good quality and what watts/# of channels should I be looking for?

Dépends of your budget !
Watts means nothing, a 4x30wrms Precision Power amp can destroy most of low budget speaker of 300w.

You will need for sure, 2 x 4 channel amp at least, or a 6 channel amp + 1 monochanel class D for the sub.
At least 1x 4 channel to drive in-boat front and rear speakers, 1 other to drive 2 to 4 (connected in parallel) tower speakers + 1 sub.
Becareful to focus on the power of the bridged channel of the sub amp, it as to be 4 times the single channel power. Ex : a 4x50 amp will give good result if it's a 2x200w briged system.
Depends also of your subwoofer. Is it a 4ohms single coil, or twin coil, 2x4Ohms ; 2x2Ohms ?

Marine, not marine amp, it dépends of your budget as well. I prefer cars amps as we have more choice and more quality/power/dynamic range amps.

For a boat, you can go for those band :

Rockford Fosgate ; MTX (not first prices) ; Orion ; Precision Power ; JBL (not first prices) ; JL audio (if you have a good budget ...) etc.
Forget about japaneese, german, Italian things, they will not give high pressure of sound on a boat IMO.

Hope it helps.

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Originally Posted by awesomesteven

I don't have any experience when it comes to audio systems so I was wondering if you guys can give me suggestions as far as what kind of amp (channels/watts) I would need.

I currently have the 4 in-boat speakers which are all 200 watts.
I also just bought a pair of tower speaker from my friend. They are 500 watts (http://www.amazon.com/dp/B0071HZJ56/..._M3T1_ST1_dp_1)

I eventually want to have a sub and add another pair of speakers along with some lights for the tower.

What kind of amp should I get (brands) that are good quality and what watts/# of channels should I be looking for?

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Steven,

Your 200W in-boats are probably 200W peak. I would look for a 4 chnl class-D amp that will deliver in the range of 75-100W rms x 4 @ 4 ohm.

Or, look for a 5 chnl that will deliver about the same on the 4 full-range chnls and about 200 x 1 @ 4 ohm on the sub chnl.

Those 500W tower speakers look like a re-branded MTX tower speaker. I would look for a 2 chnl amp that will deliver about 100-125W rms x 2 @ 4 ohm, or a 4 chnl that will deliver about 150W rms x 2 @ 4 ohm bridged.

Look for amps that are Class-D as they are more efficient. This means that draw less battery amp hours to produce the same watts output of other less efficient amps.

I have 4 in boat speakers and I have 4 tower speakers all connected to a 1200w 4 channel amp. My teacher in my electronics class suggested to use a series parallel setup when wiring up the speakers and I was able to power all 8 off that 1200 watt amp having them bridged down to two channels. The tower speakers looks like you should be around 250W each if that 500W max is per speaker. I would get at least (1) 4 channel amp for the mids and highs, and either a mono block or 2 channel amp for the sub when you get to that point of adding in the sub. I am running (1) 4 channel amp for my mids and highs and (1) 2 channel amp bridge to one channel for my 15" sub.

If you want to add another two more speakers on the tower then you should look at if you plan to run one or two amps for the mids and highs then go from there. Depending on the wiring setup you do you need to make sure you have an amp that can handle the ohm rating those speakers will be running at. My series parallel wiring was able to keep me at 4ohm on each of the two channels I am using on my amp for my mids and highs. You don't want to wire it up and over load your amp so look and see what wattage and at what ohms you will be at to make sure the amp can handle it.

Thanks for all your help guys!

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Originally Posted by a_deleon

I have 4 in boat speakers and I have 4 tower speakers all connected to a 1200w 4 channel amp. My teacher in my electronics class suggested to use a series parallel setup when wiring up the speakers and I was able to power all 8 off that 1200 watt amp having them bridged down to two channels. The tower speakers looks like you should be around 250W each if that 500W max is per speaker. I would get at least (1) 4 channel amp for the mids and highs, and either a mono block or 2 channel amp for the sub when you get to that point of adding in the sub. I am running (1) 4 channel amp for my mids and highs and (1) 2 channel amp bridge to one channel for my 15" sub.

If you want to add another two more speakers on the tower then you should look at if you plan to run one or two amps for the mids and highs then go from there. Depending on the wiring setup you do you need to make sure you have an amp that can handle the ohm rating those speakers will be running at. My series parallel wiring was able to keep me at 4ohm on each of the two channels I am using on my amp for my mids and highs. You don't want to wire it up and over load your amp so look and see what wattage and at what ohms you will be at to make sure the amp can handle it.

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Just an FYI, your series/parallel with 4 ohm bridged load results in each amp chnl "seeing" a 2ohm load. Same is if a pair of speakers were wired in parallel on each chnl. 4 chnls running @ 2 ohm is a lot to ask of an amp, but if tuned good, then no problems other then maybe some overheating on really hot days.

How do you get 2 ohm at the channel if in series two of them will bring it up to 8 ohm and when you put both pairs that are running in series run in parallel that would bring both sets down to 4 ohm across all the speakers. I have those 4 running at 4 ohm on one channel and the other channel is running the same for the other 4 speakers when I bridge my 4 channel down to 2 channels. I haven't had a problem over over heating it and I don't even need my gain more that half way up maybe 5/8 of the way up.

He suggested this way to wire it up to keep it where it wouldn't over heat and ask a lot from the amp. I messed up one amp because i forgot to calculate what resistance I am running and ran the speakers all in parallel so I ended up dropping it down to 1 ohm at the channels.

When you bridge an amp, you are using 2 chnls to gain their combined output. Each chnl is seeing half of the bridged load. In your case, you are bridging a 4 ohm load comprised of four 4 ohm speakers in a series/parallel configuration. With a 4 ohm load bridged across two chnls, each chnl is seeing a 2 ohm load, thus the combined output to the 4 ohm bridged load is equal to the amp's 2 ohm x 2 output.

Here is an example:
125w rms x 4 @ 4 ohm
200w rms x 4 @ 2 ohm
400w rms x 2 @ 4 ohm bridged

See the math? with 4 2 ohm loads, one per chnl, the amps rms output is 800w rms. With two 4 ohm loads bridged, the amps output is the same 800w rms. So i am just stating that your configuration is the same net output to all 8 speakers and the amp is running at the same load per chnl as if a pair of speakers wired in parallel where wired to each chnl.

If you are running the same 8 speakers as before and ran a 4 chnl amp before and used all 4 chnls to power all 8 speakers, I do not see how you had a 1 ohm load on any chnls.

Ok I see what you're saying on it being equal to the 2 ohm load. I might need to turn down my gain on the amp to help not burn up my speakers then. My kicker speakers on the tower are 65w rms according to the Kicker 6200 manual. So if I am getting 600w @ 4 ohms bridged I only need 260w rms for those speakers to run as designed. I have it about 3/4 of the turned up so if I am looking at it correctly I am pushing more then what those speakers need when bridge down two channels down to one right? This is where i got confused when I would talk to my teacher about this. I understood that we can make the resistence go up and down and that we just add all the wattage together to see how much we need to have there to provide the power to all the speakers.

As for when I messed up my previous amp I had 4 speakers on one of the bridged channels. I had all 4ohm speakers in parallel so that would have put it down to like 1 ohm when all 4 are in parallel right?

yes, four 4 ohm speakers wired in parallel would be a 1 ohm load. Bridging that would be placing a .5 ohm load on each chnl. Not only a rare few mono amp will handle a .5 ohm load.

Regardless of impedance load, number of speakers or speaker type, gains should never be above half way in general. Even with a low 2V head-unit, we rarely find the gains at or above half way. I would google "gain setting" and fallow one of the 3-4 good methods. They can be set by ear or with a DVOM or O-scope. I probably have one I can post here, i juts need to did it up.

Im gonna take a stab and say that you 1200W amp is 600W rms. This gives you a 300W x 2 rms @ 4 ohm. This has each speaker netting 75W rms. Thats spot on. Reset the gain, make sure the cross-over filters are set to hi-pass on all chnls and set the frequency to 120Hz for the towers and 120Hz for the in-boats if they are also 6.5" speakers.

We cant change the resistance of the speaker(s), only change how multiple speakers are wired together, thus ending up with a predetermined impedance. Theres only so many ways to wire the speakers, so we already know what impedance loads we can end up based on ohms law. Its just a matter of choosing which configuration is best for the amp.

You're correct on the ratings for my 1200w amp. That's why I was curious on the series parallel wiring when we were talking about resistors and my teacher had mentioned that it works the same with speakers. I knew with the speakers I wanted to run and just adding all them up would tell me how much wattage I would to push the speakers I would be able to get away with it on this amp.

I've been so busy I have not had time to look up how to tune your amp using the O-scope. I've asked my teacher and he would show me just that I would need to bring a 12V source that would be able to handle the amp. Just with classes going from 16wks to 8 wks it makes it such a rush there is no time to show me how to tune the amp. We have the O-scopes sitting there in the class room that I want to try and mess with my amp during our breaks. DVOM = digital volt meter correct? If so I've never seen anything posted up on using a volt meter.

As for the cross-over filter I have a low/full/and hi-pass setting on it. I have all my speakers set on the full setting right now when it comes to that cross over. I will adjust my 1 channel for the tower speakers to be at the setting you recommended. The interior right now are (2) 6.5's and (2) 6x9 speakers.

Definitely run all 4 chnls on Hi-pass, which will be controlled via 2 switches. This will cut out those lower notes that those speakers will not want to play anyway. Yes, DVOM = digi volt/ohm meter.

If you budget permits and you have space, your setup could really benefit from another 4 chnl amp. This would allow the current 4 chnl driving 4 speakers, to run more conservatively driving only 4 speaker @ 4 ohm p/chnl. You will not have an audible drop in volume from the tower speakers, but you may gain some clarity from them at higher volume levels because the amp is not running so hard. Next is the in-boats. You should really get those 6.5's and 6x9's on separate chnls. The 6x9's are about 2/3rds more surface area then the 6.5", so they will deliver much more mid-bass is allowed. But since they are pared with a smaller 6.5, you will need to tune the amp for the smaller 6.5. This leaves some of the 6x9's potential on the table so to speaker. With the 6x9's on their own chnls, I would like to see them tuned hi-pass down to 80Hz, maybe even a little lower after listening to them.

Here is a DVOM gain setting

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Tools you need......
1. A multimeter that can display AC voltage

2. A tone cd with tones in the ranges you play....
I usually use 40Hz for sub channels and 800Hz - 1400Hz or so for my mids and highs. If you have your highs on a channel, you can use 18000Hz+ for them.

Figure out what voltage you need to have on each channel using the manf. specs:
Ohms law regarding voltage
volts = sq.root of watts x ohms

So if your amp is rated to 200 watts @ 2 ohms, then you want to have 20 volts leaving the speaker terminals.
200x2=400.....sq root of 400 = 20 volts......

To setup......
1a. Turn the amp gain all the way down.

1. Put the tone cd in and set it to loop on the track, unless you have a length track.

2. Unplug at least one side of your speaker output.

3. Turn the headunit up to about 3/4 volume, this is a safe zone for most head units.....higher will result in the HU clipping the signal before it even gets to the amp.

4. Take a reading on the amp terminals in volts.....

5. Adjust the gain until it falls into the previously configured formula.

Repeat for the other inputs.

Once it is all done, hook all the speakers back up , and then adjust the levels for the speakers playing to loudly by turning them down....you do not want to turn up any gains as they are already at max.

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By ear:

Start with all gains low but not off and all RCAs connected.
With the head-units EQ flat and loudness off, find its max un-clipped, no distortion volume level, which it right about 75%.
with only one set of speaker RCA's hooked up, as in only the speakers linked to the gain dial you are going to set, getting music, turn the gain dial up until you hear the speaker(s) distort (crunchy crackly sound) then back off a notch. Now unplug that RCA so those do not play for now.
Plug up another RCA for the next gain dial and repeat the procedure. Continue until you have all gains set to just below the distortion point. With the system off, reconnect all RCAs and power up.

Thank you so much for all the info!! This is something I've been looking for to try and tune my setup on the boat. I had to replace my floor and stringers along with get me some vinyl seats made up so my budget this year didn't allow for anymore audio parts. The (4) kicker 6200's on my tower was all I could really get right now since I just did the floor and I ended up putting a new paint job on the top half of the boat. I want to go with a third amp later on but I was going to look at that next year because those kickers would come down from the tower and i would get me some wetsound tower speakers and that would call for their own amp to drive those. The kickers would replace these interior speakers when they come down off the tower.

I will have to look for a cd to tune with once I get the new head unit installed since I am switch head units this year. As for the 6x9's I have it running in series with one 6.5 on each 6x9 speaker. What would you suggest for wiring up the interior since they are on a bridged channel in series/parallel? If I put each size in series and on channel 3 & 4 to split the two sizes up what would that do? I need to look at my head unit again because I don't remember how many outs are on my new head unit, the one that came with the boat had only one out so I had to use Y splitters to send an input signal to the 4 channels and also to the input of the sub amp. So I'm sure splitting that signal up like that only hurt the end result.

Sorry to thread jack awsomestevens thread...might be some helpful info for him as well.

Talk about knowledge being dropped! I guess this thread was appropriately titled!

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Originally Posted by a_deleon

Thank you so much for all the info!! This is something I've been looking for to try and tune my setup on the boat. I had to replace my floor and stringers along with get me some vinyl seats made up so my budget this year didn't allow for anymore audio parts. The (4) kicker 6200's on my tower was all I could really get right now since I just did the floor and I ended up putting a new paint job on the top half of the boat. I want to go with a third amp later on but I was going to look at that next year because those kickers would come down from the tower and i would get me some wetsound tower speakers and that would call for their own amp to drive those. The kickers would replace these interior speakers when they come down off the tower.

I will have to look for a cd to tune with once I get the new head unit installed since I am switch head units this year. As for the 6x9's I have it running in series with one 6.5 on each 6x9 speaker. What would you suggest for wiring up the interior since they are on a bridged channel in series/parallel? If I put each size in series and on channel 3 & 4 to split the two sizes up what would that do? I need to look at my head unit again because I don't remember how many outs are on my new head unit, the one that came with the boat had only one out so I had to use Y splitters to send an input signal to the 4 channels and also to the input of the sub amp. So I'm sure splitting that signal up like that only hurt the end result.

Sorry to thread jack awsomestevens thread...might be some helpful info for him as well.

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Since a typical stereo amp only has a single gain control for the two chnls and a 4 chnl, which is basically 2 stereo amps in a single chassis, it only has a gain control for chnls 1/2 and one for 3/4. So no matter how you wire the 4 speakers to those 2 chnls, as long as the 6.5's and 6x9's are paired together on the same half of that 4 chnl, you will need to tune the amp to the liking of the smaller 6.5".

Putting the 6.5's on the head-unit, leaving the larger 6x9's to chnls 3 and 4 by themselves will solve the tuning dilemma, but from a power an volume stand-point, I would rather see the 6.5" get amplified power with the 6x9's lacking that additional mid-bass. I would leave the current wiring config as is and just retune for now. Then later revisit another 4 chnl for the in-boats or what ever amp is the best match for the new tower speakers.

Thanks for the info, I will just leave it alone for now and adjust my audio this weekend when I have some time to install the new head unit as well.

I want to put the two tower speakers on the amp. Would I bridge these the same as subs? right(+) to left (-) for front and same for the rear channels?


My friend had a cpt4-800 amp that he gave me.
Channels & Class - 4 Ch. A/B
MAX Power - 800
RMS @ 4Ω Bridged - 2 x 200
RMS @ 2Ω - 4 x 100
RMS @ 4Ω - 4 x 80

Steven,

Yes, you would bridge a full-range speaker just the same as a sub. You will connect the speaker + to one chnl's + and the speaker - to the paired chnl's - terminal. 200W rms is a lot for even a top-shelf 6.5" full-range speaker. Tuning is going to be crucial and their will need to be some discipline on the volume dial.

Wylie thanks again for the tip on how to tune it.

I did by ear tonight after installing the new head unit. I couldn't find my volt meter but started off under half way up on the gain and went up from there. Wow!! Those kickers on the tower are much louder now and really clear and the interior are loud and no distortion from them. I just need to grab an extra rca cable for the sub amp and it's all wired up and good to go.