bass problem in a sailboat


Hi!

I have a sailboat with a nice marine-grade stereo, built by Poly-Planar. There are four speakers, powered by a 4 X 45 (180 watts total) head unit. The speakers each have a 5 1/4" "woofer". I generally like the sound. The not-so-low bass is great, but I'd like to boost the really low frequencies just a little. I listen to mostly classical music, and I miss a few very low notes that I hear clearly on my home system. I'm NOT talking about great volume. I just want to boost the very low bass a little. I did this once years ago in a Camaro by simply adding an equalizer to the factory system. I DON'T want to add an amplifier and subwoofer because I don't need the extra magnetic field nor the additional power drain. An equalizer also seems inappropriate because, in this case, it would be a "set it and forget it" thing that I would hide somewhere. Is there a simple way to boost just the very low notes a little with the existing speakers and head unit?

Regards,
Troy Scott
tscott1217d0eb
if you want to get the lowest bass from your sailboat, i would recommend the longest fishing line available. or maybe a "sub" woofer? :-) sorry, couldn't resist! happy holidays!
Bass fishing in a sailboat? That may be your problem right there! :-)
It may limitation of either the speakers or pre-amp stage not delivering the frequency range or both. If all 4 speakers are in same area why not try getting new speakers? Two that deliver better low mid to high and two that deliver mostly low freq..
Just a thought.
I'll second theo. New speakers may make a world of difference.
180 watts is not a "ton" of power either. Consider more efficient speakers. There are some 2 ohm jobs out there that will sound a lot louder (produce more bass with less volume).
The drawback is that many speakers are that are rated at lower impedance are less efficient.
Finally, are the speakers in good enclosures? You may consider better enclosures or even speakers with baffles or enclosures attached. Look at Niles or Sonance for ideas with in-walls.
If you remount the speakers (tightly, waterproof, sealed well) in the bottom (hull?) of the boat so that the water itself acts as a cushion, this will provide just what you want. Not many people have the opportunity you have to use huge quantities of water as a suspension medium. Hemingway did this in the 40's
I'm still working on the problem of getting better bass from the system. As I said, I have a four channel head unit with four times 45 watts, 180 watts total. I'm currently using four 6" by 6" by 9" box speakers with it. The sound is generally good with the exception of very low bass notes. I'm missing really low notes that I hear on the home system. So far I've bought three things. I've bought a Sony woofer. I also bought a device which I thought would enable me to combine the bass from two channels of my head unit to run the one woofer. Fortunately a consultant from Crutchfield explained to me that receiver/"head units" aren't "bridgeable" and that the device is incompatible. He also showed me ( and sold me) a Profile HA700M, which is designed to combine two channels safely, amplify the signal some more, and run a woofer. However, I'm trying to keep this simple. I'm now thinking that I don't need ANY of what I've bought so far! I came across some dual voice coil subwoofers in Crutchfield's online catalog. I'm now thinking that I could simplify this whole installation and probably end up with better sound. I think I should eliminate two of the four full range box speakers. That would free up two 45 watt channels which could then run one dual voice coil subwoofer. The whole system would then consist of:
One head unit with four times 45 watts,
Two full range speakers, and
One dual voice coil woofer with two 70 hz low pass filters.

Thoughts, please?
Hello again,
I't's been suggested to me that my idea of running a dual voice coil woofer directly from two (at 45 watts each) of my four channels wouldn't be satisfactory. I still think it might work, especially since I'm only after the missing low pitches, NOT great volumn. Thoughts, please?

Regards,
Troy
With an open boat, the bass will simply dissipate into "thin air". Cars are enclosed and very small which enables the bass to resonate like mad.

First thing may be to find a spectrum analyzer to see what frequencies are missing. It may be quite surprising...

You may want to consider something like a "bass shaker". These little devices can be mounted either on you seat or in a boat, on the floor. You will need some sort of sub crossover which will send all of the signals below 60-80 to the bass shakers. Check out partsexpress.com for sub amps/crossovers. You may be able to run 2 of your channels to the amp/crossover and then to the speakers. The amp will divide the signal, amplify it, and send the bass to the shakers.
WRT "bass shakers", I do remember from long ago a device that could be attached to a wall to transform the wall into a speaker. I'm guessing that's what the "bass shaker" is. I'll check into it.

BTW, the sailboat in question is a Cape Dory 36. The displacement is over 16,000 pounds, and there are two nice cabins which are probably acoustically similar to a small room.

Regards,
Troy
Hello Troy,
FYI, I owned a Robinhood 33 (hull no. 2) which is a downeast flybridge cruiser using a modification of the Cape Dory 33 hull. Robinhood Marine is the sucessor to Cape Dory- they build the Robinhood 36 which is identical to your 36, I think they are now close to hull no. 20.
a small Bazooka cylinder-shaped active car-type sub might work out for you; they don't cost a whole lot. One model isolates & sums two-channel line-level inputs driving a single cone via an integral amp. I think their larger model handles the channels separately. Simply tee-connect the left & the right channels respectively at line level in either case.
I had Poly Planar head unit and speakers in my boat and in my hot tub. All factory installed.....and all way below average in every way. Overpriced as well. Not 45 watts constant power.....peak only. I would try new speakers first. Bigger, if possible. Look for something with a high sensitivity rating. Also pay attention to the specs as to how low they will go. If you do not get the bass you are looking for, at least you will have improved the sound dramatically. A passive bazooka tube may be the answer if your head unit will power it. Crutchfield will let you return it if it does not work out. The amplified version would shiver your timbers, but you have ruled that out.
By the way, bass shakers are made to go under your seat and vibrate to the music. They are not speakers at all.
Another idea (and probably the best)would be an inexpensive head unit with bass management. Crutchfield has lots of those. Look for one with lots of internal power. I would look at Crutchfield's comparison chart and focus on the watts per channel. I like the Alpines, but I think you will find Kenwood to be the watts winner. Good luck.
Baffled Bob,

Thanks! Your response is the most helpful so far! Right now I'm trying this: a dual voice coil subwoofer (hate that term) operated by two of the head unit's four channels. The other two channels will operate two of the original four PolyPlanar box speakers. We'll see. I intend to keep playing with this until I get it "right". I'm learning a lot!

Regards,
Troy
Linkster,

In fact, I bought my Cape Dory 36 from Robinhood Marine. I'm in the midst of a major refit now, doing the work in my hangar. When I'm finished, it will look like the R36 brochure boat!

Regards,
Troy
Folks,

If anyone here is still interested in my sailboat stereo project, here's the latest:
I bought the PolyPlanar model 250 amplified subwoofer (which includes a dual voice coil subwoofer) and added it to the system. When I adjusted the gain on the bass amplifier, it ended up very near the lowest level. The overall effect was a substantial improvement. The lowest notes were much better, but the upper bass still seemed boomy. Out of curiosity, I removed the bass amplifier from the system and connected the DVC subwoofer directly to the two front channels in place of the two bookshelf speakers that had been there. To my surprise, the subwoofer was actually LOUDER that the level I had set with the bass amplifier. Of course, without the bass amplifier there was no crossover for the woofer, so I had some out-of-place treble on the woofer. Another oddity: the sound from the subwoofer was not perceptively less when I added the two bookshelf speakers back to the front channels along with the subwoofer. However, to my ears the bass actually sounded better than the system sounded with the bass amplifier. Lesson learned: I think all I really need to do is add a very good DVC subwoofer to the set of four book shelf speakers. I've ordered an Infinity 12.1 dual voice coil subwoofer from Crutchfield, along with three different sets of low pass filters: 50hz, 70hz, and 100hz. I plan to try all three to see which works best.

Interestingly, almost everyone I've talked to about this problem has misunderstood. I'm after something subtle here, not a floating boom-box. We have an audiophile system at home, and I'm accustomed to hearing all the notes on my CDs. All I want to do is improve the system enough to hear everything clearly.

Regards,
Troy Scott
The Infinity sub needs a minimum of 75 watts RMS. You have about 15 watts RMS max. But.... at 96 db sensitivity there might just be enough bass to fill a sailboat cabin. I would be interested in knowing how it sounds.
Remember how power hungry bass is. Even if I were looking for "subtle", I would want enough power for headroom without any distortion. Getting that note at 25hz requires a heck of a lot more power than a note at 15khz, especially if you want clean, tight and fast.
Happy Listening.
Baffled,

I'll let you know!

Regards,
Troy
Elevick,

I agree. Bass requires power. That's why I'm inclined to believe the RMS output of the PolyPlanar MRD-60 is closer to the 45 watts per channel that the 15 watts that has been suggested. It drove the first dual voice coil subwoofer quite well. I'm hoping this Infinity will be even better.

Regards,
Troy Scott
tscott, don't be fooled by power specs. Poly-Planar advertizes UP TO 45 watts per channel. That's peak power on a clear day, downhill, with a good head wind. Constant power (RMS)is another story. Still, I am constantly amazed at what the average head unit amp is capable of. I am cautiously optimistic.
Baffled,

I'm optimistic too. The speaker hasn't arrived yet, but I've made the preparations. The speaker should be sensitive enough to do enough with a little. Regardless how much power the head unit actually has, it would play the four bookshelf speakers and the dual voice coil subwoofer (without a low-pass filter!) louder than I would ever listen. I'm hoping that this new, 2" larger and probably much more efficient DVC subwoofer (this time WITH a low pass filter) will be even better. Thanks for your help! I'll let you know.

Regards,
Troy
Gentlemen,

Last evening I finally had the opportunity to try a new tactic. I reinstalled the PolyPlanar powered subwoofer in the boat, except I added a 70hz 12db per octave crossover (to override the 200hz crossover built into the bass amplifier). WOW! What a difference! With only the 200 hz crossover, I had to turn the bass speaker down so low (to avoid upper bass boominess) that it didn't help the 25hz range at all. With the 70hz crossover, I was able to turn the bass amp volumn up to about 90%, enough to really help the very low pitches. Today I plan to try a 50hz crossover and possibly turn the bass volumn up to 100%. I'll let you know!

Regards,
Troy Scott