A different sub location??

[jcyamaharider]

I do not recall if anyone has stuffed a sub in the location where we all put our ballast bags on the starboard side or not but I am going to give it a shot. I think pointing the sub up and firing on the hollow compartment will act like a bandpass box and majorly amplify the sound. My box is getting 3 coats of poly right now and then is getting carpeted. Going in the box is 2 12" mm1240 DVC subs. The inside area of the box is .91 cubic foot roughly.

If someone has put a box here please post up results, I am dying to hear what it is going to sound like!!

I should get my subs Thursday.

 

[woodard1983]

I recall some posts from the other site that had a sub in that location, but I think it was facing forward if I remember correctly??

I'm assuming that the .91 cu ft is for each sub and not total interior volume correct?

Let us know how it works out, that might be a spot of interest for me when I start moving things around to add ballast next year

 

[jcyamaharider]

I recall some posts from the other site that had a sub in that location, but I think it was facing forward if I remember correctly??

I'm assuming that the .91 cu ft is for each sub and not total interior volume correct?

Let us know how it works out, that might be a spot of interest for me when I start moving things around to add ballast next year

Yep, per sub.... Min requirements for the sub are .88 so I am a little over min. That is the exact reason for choosing this spot in the boat. I need all the room I can for the port side ballast bags and still want 2 12's in the boat. I also need room for the 2 batteries and a little bit of storage for items.

 

[txav8r]

I built an enclosure for my single 10" sub, but it is going to be mounted with the sidewall sandwiched between the sub and the enclosure. Will these subs be vented to the outside @jcyamaharider ?

 

[jcyamaharider]

Yes these are going to be vented somehow. Just have to choose the right location to put the vent.

 

[woodard1983]

Do you guys remember the person on the other site that used the cubby on the port side to make a vent? They basically used that hole and made a "screen" with frame to cover it. That is what I am planning on doing next year.

I looked on the other site, but couldn't find it in my searches

 

[David Analog]

By definition a bandpass box is a tuned resonator...AND...a filter. In a BP box you increase the amplitude and simultaneously limit the bandwidth. However, there is nothing 'tuned' about your scenario. And a bandpass enclosure is well known as a tricky design that doesn't perform well unless you precisely hit the mark with a specific driver with bandpass-friendly Thiele/Small parameters. You have a sealed rear enclosure (like a bandpass) and a vented front enclosure (vented into the cockpit) but in your case the front enclosure is infinitely expansive and includes the adjoining gunnel and other cavities, thus very compliant. So you will get some of the filtering and you will get significant attenuation/losses but you will see none of the boost characteristics of a tuned bandpass. What you will notice is an increase in the tactile low bass that is transmitted through the boat structure. So more of a boat shaker and less of a musical bass maker. This also sets up a significant subwoofer phase delay which makes seamless midbass integration and transition with the in-boat coaxials futile.
Your goal is to introduce a vent that is at minimum the approximate unobstructed surface area of the combined woofers. The larger the vent surface area the lower the vent resistance (bigger vent is better) which serves to minimize some of the impact of the front enclosure displacement and compliance (smaller front enclosure is better). Without a large vent there is little impetus for the bass energy to flow out of the compartment and into the open cockpit area.
Also, you want the woofers stood off any adjacent plane by a distance of 3 to 4 inches for a 12-inch sub. Any reduction in radiating surface area, especially in the context of 'inside' a compartment will result in additional acoustic losses.
I understand the benefits of BIGGER woofer surface area. In an open boat there is no other method that is as efficient. Not more excursion. Not more power. But a concealed woofer(s) detracts from many of the benefits you would have when direct-radiating. Unfortunately the boat doesn't always cooperate. The above is an explanation of how things actually work acoustically. Take it into consideration and do your best.

 

[txav8r]

I think @Cowboy Casey mounted his subs with enclosure behind, sandwiched to the head compartment wall. I think he followed your advise @David Analog.

 

[jcyamaharider]

Do you guys remember the person on the other site that used the cubby on the port side to make a vent? They basically used that hole and made a "screen" with frame to cover it. That is what I am planning on doing next year.

I looked on the other site, but couldn't find it in my searches

I think that was @redthumper9 and he posted it here.

 

[txav8r]

Have you considered fixing a miunt to your box and mounting te speakers they the wall to the box @jcyamaharider . It would achieve the best dynamic you could get, but I don't know if the wall face will take a 12" speaker. The 10" is even tricky.

 

[jcyamaharider]

Have you considered fixing a miunt to your box and mounting te speakers they the wall to the box @jcyamaharider . It would achieve the best dynamic you could get, but I don't know if the wall face will take a 12" speaker. The 10" is even tricky.

I did and like you said Mel, it just doesn't fit. I measured, 12" inches is the side wall where I would put it vented to the cabin.

 

[jcyamaharider]

By definition a bandpass box is a tuned resonator...AND...a filter. In a BP box you increase the amplitude and simultaneously limit the bandwidth. However, there is nothing 'tuned' about your scenario. And a bandpass enclosure is well known as a tricky design that doesn't perform well unless you precisely hit the mark with a specific driver with bandpass-friendly Thiele/Small parameters. You have a sealed rear enclosure (like a bandpass) and a vented front enclosure (vented into the cockpit) but in your case the front enclosure is infinitely expansive and includes the adjoining gunnel and other cavities, thus very compliant. So you will get some of the filtering and you will get significant attenuation/losses but you will see none of the boost characteristics of a tuned bandpass. What you will notice is an increase in the tactile low bass that is transmitted through the boat structure. So more of a boat shaker and less of a musical bass maker. This also sets up a significant subwoofer phase delay which makes seamless midbass integration and transition with the in-boat coaxials futile.
Your goal is to introduce a vent that is at minimum the approximate unobstructed surface area of the combined woofers. The larger the vent surface area the lower the vent resistance (bigger vent is better) which serves to minimize some of the impact of the front enclosure displacement and compliance (smaller front enclosure is better). Without a large vent there is little impetus for the bass energy to flow out of the compartment and into the open cockpit area.
Also, you want the woofers stood off any adjacent plane by a distance of 3 to 4 inches for a 12-inch sub. Any reduction in radiating surface area, especially in the context of 'inside' a compartment will result in additional acoustic losses.
I understand the benefits of BIGGER woofer surface area. In an open boat there is no other method that is as efficient. Not more excursion. Not more power. But a concealed woofer(s) detracts from many of the benefits you would have when direct-radiating. Unfortunately the boat doesn't always cooperate. The above is an explanation of how things actually work acoustically. Take it into consideration and do your best.

I had to read this 4-5 times to dumb it down for myself to understand, but I think I have it. The issues I run into are 1. the size of subs I am using, 2. not wanting to cut a huge hole in the side of my boat for it not to work, 3. loosing valuable storage space. My boat is mainly used for surfing and that takes up all of my port storage space for ballast. With all of that aside I would love to mount these facing the cabin because I know that direct radiation is the only way to get 100% with what we have.

 

[David Analog]

A acoustic manifold can be effective in coupling the woofer & enclosure baffle to a vent on the seating console wall. The change in shape from one end of the manifold to the other is fine. A small degree of surface area reduction will also pass. And the manifold length should be as short as possible, just a few inches. It's a monster project even with a single 12" sub. Two 12" subs would be an Excedrin headache #177.

 

[David Analog]

I had to read this 4-5 times to dumb it down for myself to understand, but I think I have it. The issues I run into are 1. the size of subs I am using, 2. not wanting to cut a huge hole in the side of my boat for it not to work, 3. loosing valuable storage space. My boat is mainly used for surfing and that takes up all of my port storage space for ballast. With all of that aside I would love to mount these facing the cabin because I know that direct radiation is the only way to get 100% with what we have.

Yeah, I know what you are after and you must take what the boat gives you without turning the boat into swiss cheese. While inefficient given the losses of concealed subs, past a point the only way to truly get more output is with radically more woofer surface area. Taint perfect but at some point you have to choose the leper with the most fingers.

 

[woodard1983]

I think that was @redthumper9 and he posted it here.

That isn't the one I was thinking of, but is actually MUCH nicer!!!

@redthumper9, any interest in making these for others???

 

[cozilla]

Do you guys remember the person on the other site that used the cubby on the port side to make a vent? They basically used that hole and made a "screen" with frame to cover it. That is what I am planning on doing next year.

I looked on the other site, but couldn't find it in my searches

I did the same thing on my boat. I think the guys boat name was Aqua Tech.

 

[redthumper9]

@woodard1983 .....I wish I had time to build a few for some of the members. I am more than happy to give dimensions and details of someone needs them. Fyi....mine did not have the little pocket already there. I think those were on the 230 models. What sucks is that we went the entire summer without kicking bumping the vent. While winterizing, I was scrubbing the carpets and vacuuming and my knee pushed the screen in and bent it. Now it has to be removed and the aluminum screen replaced.......ughhhhhh!

 

[OperationROL]

That isn't the one I was thinking of, but is actually MUCH nicer!!!

@redthumper9, any interest in making these for others???

I am sure you are talking about @CarFanatic. He replaced the little shoe cubby with a sweet looking screen that I in fact inherited when he moved to his current Tige . Maybe he will post a pic. The links to the pictures in his old posts over on the other site are missing (actually, the pictures are missing).

 

[David Analog]

Odin with Earmark Marine (sales@earmarkcaraudio.com) does this type of custom fabrication for his customers. He already has a number of custom grill and vent options on the shelf, including stainless steel mesh with aluminum or vinyl clad birch trim rings or King Starboard polymer vents. A softer aluminum mesh grill usually gets a hidden-from-behind supportive structure as standard practice for the reason stated above (ie: kids, feet, boards, etc.).

 

[GTBRMC]

SeaTech at YJB also used that little port side cubby as a vent.
http://yamahajetboaters.com/forum/viewtopic.php?f=57&t=43815&p=375541&hilit=vent+subwoofer#p375541