DiyMobileAudio.com Car Stereo Forum banner
1 - 20 of 46 Posts

·
Registered
2005 Mastercraft X7
Joined
·
20 Posts
Discussion Starter · #1 ·
Hello everyone.

I have been reading most of the boat threads here, and have not been able to gain a sufficient understanding of the science of subwoofer selection in the context of a boat. Here are some common thing I have seen regarding subwoofers in boats:

1. Efficiency, efficiency, efficiency!
2. NO transfer function
3. Open air - no cabin gain
4. Extremely high ambient noise to overcome
5. Poly or Aluminum cone w/ rubber surround for resistance to water

Now given that general information, I have additional constraints to impose. Its a tiny boat, and there is only one single spot that could fit a traditional box subwoofer enclosure - under the passenger seat storage area. We already use 90% of this space to hold tools, spare parts, coast guard required life jackets, fire extinguisher, oar, etc. Plus the two existing amplifiers and battery are in there (easy access to power for adding another mono amp). But if I HAD to, I could squeeze a smallish enclosure in there. From what I've read, these locations are sub-optimal because there is no way for the air to vent out to the rest of the boat when the seat is down. I'm not going to open up the seat just to listen to music, I would loose 1/3 of my seating capacity to do so.

The boat already has a subwoofer and 6 speakers.

4x JL Audio M770-CCS-CG-WH 7.7" component speakers in the boat
2x MB Quart QM 160 Q 6.25" w/ QM 218.61Q x-overs and tweeters on the wakeboard tower (these used to be the JL M770s but the previous owner cut them out and put these MB quarts in there, presumably because they blew out the JL speakers. The x-overs are just sitting loose in the tower cans, nothing holding them down. Something I should fix at some point...)
1x Kicker Solo Classic S10C in an IB setup under the helm on the kick panel. This is the factory location for the subwoofer. From factory it came with a JL MC-10IB5-4 marine IB subwoofer, but it was replaced by the previous owner (IDK why).
1x JL E4300M amp powering the 4 cabin speakers, each on their own channel (45W x 4 at 4 ohm)
1x Kenwood KAC-X4D amp powering the two tower speakers each on ch1 and ch2 (120 W x2 at 4 ohm), then ch3 and ch4 bridged to power the sub (300 W at 4ohm)

FYI input gains were set on each channel using the appropriate test tones, eq off, etc, with an oscilliscope to watch for clipping.

The Kicker sub is very quiet, even when turned up a lot. Manual says it is meant for sealed enclosures only, and should have .66 cu ft. Its just sitting in the kick panel, open air. However, that area directly behind the sub is kinda small, so I'm not sure if it qualifies as a true IB. There is nothing to divide the air space between the open air area where the drivers legs go, and the area behind the sub, if that makes sense. Regardless, this sub in its current envrionment is leaving a lot to be desired.

So I'm trying to decide:
1. Keep the current subwoofer in the existing location and find a sealed tube style enclosure that will get me close to .66 cu ft. This seems very implausible given the cramped space behind the sub.
2. Get a bazooka tube style subwoofer with the port facing the driver (venting out to the boat area, not back into the space under the helm), and just cut out the hole a little larger to slide that into place.
3. Get a kicker tube style subwoofer with a passive radiator pointing away from the driver (woofer facing driver, radiator facing opposite), and again put it in the hole cut out a little larger.
4. Use an IB subwoofer, pro grade with high sensitivity and xmax, perhaps step up to a 12". Something like a AE IB12AU or AE SBP12, or if there are cheaper options that are high efficiency, high excursion, and poly/alum cone I'm all ears. (Dayton? Infinity? JBL? Polk? JL?).
5. Get a prefab powered sub + enclosure and place it under the passenger seat.

Which of these options (or something else?) would give me the best sounding subwoofer for a boat? I listen to pretty much everything (rock, metal, country, hip-hop, pop). I don't need to impress anyone with the bass output, I just want there to be, say, double or triple the output I have now (mild bass when cranked all the way up while stationary, as soon as we start moving the bass disappears).

Thanks for reading this giant wall of text and I'm looking forward to everyone's input.
 

·
Registered
Joined
·
5,605 Posts
I'm having trouble understanding to what degree if any the existing sub's front wave is isolated from the rear wave (and also how this will be accomplished in your proposed IB configuration).

To the extent there is not adequate separation of the front and rear wave, the result will be low output due to cancellation.
 

·
Registered
Joined
·
2,147 Posts
What you have now is not IB - technically it would be called an Open Baffle, bass frequencies are yards long and unless the baffle the speaker is mounted in is longer in all directions than the frequencies it is producing then it's an Open Baffle and the last thing you want in a boat while under way.

In order to be IB the airspace behind the baffle has to be totally separated from the front airspace. Simulating a sealed enclosure but with INFINITE space behind the speaker. This can be done in boats when they have sealed gunnels or large bench seats or engine covers where the air on the back side is closed off from the front side. The only way you can get any bass from an open console like that is to put some sort of enclosure under there - ported for the gain is the best option.

The storage area under the passenger seat will work if the opening to gain access to this dry storage is sufficiently sealed when closed. Having it full of USCG Safety Items is not a problem cause most Subs don't need the kind of airspace that moderately sized boats have in their dry storage. But the key thing is to find out if it's "sealed" and I don't mean with that hard rubber edge guard that most fiberglass boats use - an actual rubber seal like on a car door.
 

·
Registered
2005 Mastercraft X7
Joined
·
20 Posts
Discussion Starter · #5 ·
Thanks for your responses!

I'm having trouble understanding to what degree if any the existing sub's front wave is isolated from the rear wave (and also how this will be accomplished in your proposed IB configuration).

To the extent there is not adequate separation of the front and rear wave, the result will be low output due to cancellation.
There is no separation. The kick panel that the sub is mounted to does not extend all the way up into the cavity, thus the front and rear air spaces are connected.

What you have now is not IB - technically it would be called an Open Baffle, bass frequencies are yards long and unless the baffle the speaker is mounted in is longer in all directions than the frequencies it is producing then it's an Open Baffle and the last thing you want in a boat while under way.

In order to be IB the airspace behind the baffle has to be totally separated from the front airspace. Simulating a sealed enclosure but with INFINITE space behind the speaker. This can be done in boats when they have sealed gunnels or large bench seats or engine covers where the air on the back side is closed off from the front side. The only way you can get any bass from an open console like that is to put some sort of enclosure under there - ported for the gain is the best option.

The storage area under the passenger seat will work if the opening to gain access to this dry storage is sufficiently sealed when closed. Having it full of USCG Safety Items is not a problem cause most Subs don't need the kind of airspace that moderately sized boats have in their dry storage. But the key thing is to find out if it's "sealed" and I don't mean with that hard rubber edge guard that most fiberglass boats use - an actual rubber seal like on a car door.
Thank you for that explanation. This helps a lot. The passenger seat compartment is by no means sealed, there is a hole the size of a softball where the side compartment joins it, as well as the interface between the seat and fiberglass not having any rubber weather stripping of any kind - just hard plastic resting on gel coated fiberglass.

Adequate baffle / enclosure / wave separation issues aside, I second the ported recommendation (tuned ~40 Hz for maximum outdoor impact, output and efficiency).
Would this ported enclosure go under the helm where the existing sub is located, or under the passenger seat? Additionally, where should the port on this enclosure be directed (if that matters)?

Since the space under the helm is limited and there will already be a large circular hole, I figured the bazooka or kicker tube style subwoofers would work well.
If its going under the passenger seat, then other geometries can be accommodated.

I prefer a pre-fab setup where the subwoofer is matched to an enclosure. I can fabricate an enclosure myself, but would prefer not to. Time is more scarce than money at the moment.
 

·
Registered
Joined
·
2,147 Posts
Would this ported enclosure go under the helm where the existing sub is located, or under the passenger seat? Additionally, where should the port on this enclosure be directed (if that matters)?
Under the helm would be better if there's room, putting a passive radiator or simply leaving the current sub in place to fill the hole won't change anything. The bass will emanate in all directions from under the open helm.

Pictures and measurements of the space under the helm (including up under the back side - not just the floor) would be helpful as we could try to help you find what you're looking for... with only 300 Watts to work with you're going to need maximum efficiency.
 

·
Registered
Joined
·
5,605 Posts
.... Would this ported enclosure go under the helm where the existing sub is located, or under the passenger seat? Additionally, where should the port on this enclosure be directed (if that matters)?

Since the space under the helm is limited and there will already be a large circular hole, I figured the bazooka or kicker tube style subwoofers would work well.
If its going under the passenger seat, then other geometries can be accommodated.

I prefer a pre-fab setup where the subwoofer is matched to an enclosure. I can fabricate an enclosure myself, but would prefer not to. Time is more scarce than money at the moment.
Perhaps you can come up with a simple way to isolate the front and rear waves of the existing sub and go from there. Or perhaps a temporary sealed or ported box to try out here and there and see what works best.
 

·
Premium Member
2016 Mazda 6 GT
Joined
·
2,431 Posts
Quick and easy get a couple of bazooka tubes. The biggest you can fit! Done!
 
  • Like
Reactions: audiobaun

·
Registered
2005 Mastercraft X7
Joined
·
20 Posts
Discussion Starter · #9 ·
Under the helm would be better if there's room, putting a passive radiator or simply leaving the current sub in place to fill the hole won't change anything. The bass will emanate in all directions from under the open helm.

Pictures and measurements of the space under the helm (including up under the back side - not just the floor) would be helpful as we could try to help you find what you're looking for... with only 300 Watts to work with you're going to need maximum efficiency.
I'll try to get some pictures of that area. Might be a few days. 300W is what I have now, but I could add an additional mono amp in the future if necessary. I dont need tremendous bass, just enough to hear it while towing a wakeboarder. Perhaps 300W isn't enough for that task, we'll see.


Perhaps you can come up with a simple way to isolate the front and rear waves of the existing sub and go from there. Or perhaps a temporary sealed or ported box to try out here and there and see what works best.
I will see how feasible sealing up that kick panel is when I go take pics. However, that the subwoofer is old enough to vote, so I don't know if there is much merit in trying to continue to use it. Correct me if I'm wrong here.

Quick and easy get a couple of bazooka tubes. The biggest you can fit! Done!
This was my thinking at first, because bazooka has such high claimed sensitivity (102 to 106 db). Is this just marketing bs or are they really that efficient? Also, given that I have to have a 4 ohm load at the moment, I am probably looking at either the Bazooka BT1214 (250W 4ohm SVC @ 4ohm), or the Bazooka BT1028DVC (500W 8ohm DVC @ 4ohm). 12" at 250W or 10" at 300W? My guess is the bigger cone area at the slightly reduced power. Another option would be to fully power the 10" at 500W with a bigger mono amp.
 

·
Registered
Joined
·
5,605 Posts
I'll try to get some pictures of that area. Might be a few days. 300W is what I have now, but I could add an additional mono amp in the future if necessary. I dont need tremendous bass, just enough to hear it while towing a wakeboarder. Perhaps 300W isn't enough for that task, we'll see.




I will see how feasible sealing up that kick panel is when I go take pics. However, that the subwoofer is old enough to vote, so I don't know if there is much merit in trying to continue to use it. Correct me if I'm wrong here.



This was my thinking at first, because bazooka has such high claimed sensitivity (102 to 106 db). Is this just marketing bs or are they really that efficient? Also, given that I have to have a 4 ohm load at the moment, I am probably looking at either the Bazooka BT1214 (250W 4ohm SVC @ 4ohm), or the Bazooka BT1028DVC (500W 8ohm DVC @ 4ohm). 12" at 250W or 10" at 300W? My guess is the bigger cone area at the slightly reduced power. Another option would be to fully power the 10" at 500W with a bigger mono amp.
Yeah, forget the old existing sub. You're going to need a LOT of output while towing a wakeboarder. I have no first-hand experience with them, but from what I gather Bazooka tubes seem like a great option for your application and preference for loaded pre-fab enclosure.
 

·
Registered
Joined
·
1,051 Posts
It seems like a loading baffle over the sub, or an aperiodic mat would help with the separation that's needed. I'm a novice at this, but I have heard it work. Delaying or restricting the front and back wave and giving the sub some resistance will provide some loading, better than none for sure.
 

·
Premium Member
2016 Mazda 6 GT
Joined
·
2,431 Posts
It’s a BOAT! It’s not worth the effort. Bazooka for the win! And two if space allows!
 
  • Like
  • Helpful
Reactions: audiobaun and gijoe

·
Registered
2017 GMC Sierra 1500 Denali
Joined
·
1,883 Posts
It’s a BOAT! It’s not worth the effort. Bazooka for the win! And two if space allows!
I didn’t know these were still around but after watching this infomercial i think it’s time to switch up my vehicle! lol

I could see totally see this working on a boat though. Ba ba diddly ba bah! 🤪

 

·
Registered
2005 Mastercraft X7
Joined
·
20 Posts
Discussion Starter · #16 ·
Yes.. Marine grade Bazooka work great on boats.If you get a powered one.. Id recommend the 250 class D series
I think I would just get a passive one since I already have the amp.

From what I can tell, the normal, non-marine version is a polypropylene cone with rubber surround. I think that's sufficient for my marine application (all fresh water, never rain, at most a few drops or a small splash of water would come in contact with it). Is there something I'm overlooking?
 

·
Registered
Joined
·
2,147 Posts
I think I would just get a passive one since I already have the amp.

From what I can tell, the normal, non-marine version is a polypropylene cone with rubber surround. I think that's sufficient for my marine application (all fresh water, never rain, at most a few drops or a small splash of water would come in contact with it). Is there something I'm overlooking?
Unfortunately, Yes. The Marine Grade has the inside of the Tube coated (basically really thick cardboard) while the non-marine is uncoated and subject to moisture destroying the Tube from the inside out.

Key thing to remember with Bazooka Tubes is that they need to be corner loaded (the output end should be 2" form a corner or wall) and if your amp is 2 ohm stable then get 2 x 10 Passive Marine Tubes and point them both into the same corner for the maximum effect.
 
  • Like
Reactions: DaveG

·
Registered
2005 Mastercraft X7
Joined
·
20 Posts
Discussion Starter · #18 ·
Adequate baffle / enclosure / wave separation issues aside, I second the ported recommendation (tuned ~40 Hz for maximum outdoor impact, output and efficiency).
How can I tell what frequency a prefabbed loaded enclosure is tuned to? Is it just the lowest number in the frequency response range? Some bazookas list 39hz-1000hz while others list 30hz-1000hz. I'm guessing I should opt for the former?
 

·
Registered
Joined
·
5,605 Posts
How can I tell what frequency a prefabbed loaded enclosure is tuned to? Is it just the lowest number in the frequency response range? Some bazookas list 39hz-1000hz while others list 30hz-1000hz. I'm guessing I should opt for the former?
From what I gather, prefabbed loaded enclosures, unless otherwise specified, are typically tuned on the high side (high 30s to low 40s). Tuning frequency (Fb) will very likely be higher than the lower end of any listed frequency response range. However, listed frequency response doesn't mean much without relative dB (F3, for example). You might contact manufacturer and request Fb. Or just go ahead and buy a Bazooka tube or two and don't worry about it. :)
 

·
Registered
Joined
·
2,147 Posts
How can I tell what frequency a prefabbed loaded enclosure is tuned to? Is it just the lowest number in the frequency response range? Some bazookas list 39hz-1000hz while others list 30hz-1000hz. I'm guessing I should opt for the former?
My recommendation would be to get the 10" Marine Passive Version. As @Grinder said, most prefab enclosures are ported around 40Hz for maximum boom and you don't need to worry about extension below the 30's in a boat as ambient noise while under way would mask any thing below there anyway. They even make a "kit" version with the mounting straps to secure it under the helm.
 
  • Like
Reactions: Grinder
1 - 20 of 46 Posts
Top