Sub Woes

[tige']

I was posting some sub issues I was/am having in Phil's "Vented Enclosures" thread but rather than hijacking that thread (even though Phil and others were giving me great input) I thought I would start one of my own.

Here is were I am at....

I started a stereo install project on my boat earlier this winter. Never doing this before I had no idea what I was getting into and started purchasing items apparently before I had done enough research.

I added tower speakers, new in-boat speakers, new head unit, three amps and a sub.

Not wanting to spend a lot of money, everything was purchased with cost in mind. The install is nearly complete and I am very happy with everything except the sound from my sub.

The sub is an Alpine 10" Marine free-air sub. I don't want to blame the sub for the sound, I think it is more my installation. If it were installed correctly I bet it would sound great. The sub sounds OK when you are listening to the whole stereo system but when I pull the RCA's on the other speaker amps and just listen to the sub you can hear it rattle, buzz and distort when pushed hard. The sub is mounted in a make-shift box that is mounted under a storage cabinet. Alpine recommends nearly a 5.0 cu ft box, I have about 2.0 cu ft. I didn't think this would really matter because it is a free air sub - apparently I was wrong..

I am using 3/4 treated ply wood for the 2 sides I had to make for my enclosure. This is probably mistake #2.

I was trying to get another sub to connect to my system to see how it would sound but I haven't had any luck finding someone that has a sub I could borrow. (This is where we left off on the other thread)

I did manage to listen to the system of the only other person I know that has a sub mounted in a boat. And that trip confirmed what I thought...his bass was unbelievable compared to what I am getting. Granted he has a much nicer and more expensive system. I would say the in-boat speaker sounds were comparable to mine but his subs rocked!! They hit hard and were very clean. He had 2 JL Audio 10" subs with a JL Audio amp. They were installed very nicely into the fiberglass front panel of the rear bench seat. So he did have a solid surface to mount them to. They are also free air subs but he had a plexiglass enclosure around the top and back of them (inside the bench seat) to protect them. It was open at the bottom.

My next step is to build an air tight sub box and try my sub in it. But I still have issues doing that.

1) I don't have 5.0 cu ft to give up for a box so I am only going to built it to about 2.0 cu ft (same size as I have now but airtight and hopefully a more solid box)
2) I am not convinced that if I build a box that will fit into the area where I want that I am still not going to have issues with rattling the plywood closet enclosure and other stuff
3) I can't get 13 ply 3/4" treated (or even non treated plywood) where I am at. So I am probably going to have to use MDF and seal and paint it. But, my boat is always stored inside and this box is out of the way of getting wet so maybe that is not that big a deal??

This thread is just me thinking out loud and giving the people who have been helping me an update on where I am at. Hopefully I can get the box built tomorrow and post an update on what I find. If this doesn't go well I am going to start looking for another sub, preferably something that is supposed to go into a 2.0 cu ft box.

[dogbert]

One question, if you have a free air sub, why use a box at all? It's designed to work without a box.

I have a free air sub in my boat that I installed in the driver kick panel. It works great. I know it will never kick as hard as an enclosed sub, but it's good enough for me.

[kana12]

dude.. if you have 2 cuft of air space.. build you a 1.75 cu ft ported pox and slam a xxx-xs 12 in there and watch your floor shake.

[wetsounds1]

The reason why they recommend such a large box is the woofer is designed to be "free air" or infinite baffle. A free air type sub is usually mounted on a panel. For instance, the factory Tige Wet Sounds XS-10FA is mounted under the drivers on that panel.

It uses the storage area as the "enclosure" So it uses that large area as it's box. A free air woofer still needs a baffle to separate the front and back of the woofer.

When using a free air woofer in a box. You need to build a large box to simulate that "free air" type set up.

So your system sounds to be the wrong type of woofer for the application. So you can try to use that same woofer in a free air type set up under the drivers dash like the factory systems.

Or you should look at replacing that woofer with something that can play in a box. For instance, our XS-12 woofer can play in a 1.2 cu foot sealed box. So if you have room for a 2 cu ft box. You have more than enough room for a 12 inch sub.

Next is location of the sub. Where is it mounted in the boat?

You said something about a storage cabinet? So is it in the boat?

Just want to make sure. As you cannot truly test the system unless you have the sub in the boat and where it will be as the sub needs to "load" off the boat.

Best location in the boat is under the drivers dash in the factory location. Those that want more bass. Step up from the free air woofer in that spot to a large woofer in an enclosure but in the same location as it loads the best and you give us the least amount of storage.

Tim
Wet Sounds

[chpthril]

One question, if you have a free air sub, why use a box at all? It's designed to work without a box.

I have a free air sub in my boat that I installed in the driver kick panel. It works great. I know it will never kick as hard as an enclosed sub, but it's good enough for me.

If I remember correctly from previous posts, his yr/model boat has only a partial bulkhead wall under the driver's console and that's what felicitated the box.

Glad you posted this in it's own thread, makes it easier for everyone to keep up with what's been suggested and tested as well as what components are involved.

Based on what you are describing, I'm leaning away from just a poor box/wrong box size, and maybe thinking a bad woofer! We could be also looking at a bad head unit, signal cable, amp, sub leads.

I cant remember what amp you are using for the sub and if we went over it's settings. How is the sub's amp getting it's signal from the head unit? - non-fade or split off another amp that's getting it from the front or rears. Is the amp set up right for a sub? Cross-over(s) switch set to "Low", Crossover dial set between 50-80Hz's (good start point)?

Have you check the sub at the amp and at the sub terminals themselves with a DVOM (volt/ohm meter) for proper resistance? It's a 4ohm coil, so should be real close at the sub and at the amp (with sub wire unplugged).

*EDIT* Ok, just looked back a couple of post: Head unit is the Clarion M475, so youve got Ft, Rr, and non-fad. Just an FYI- the non-fad is adjustable, may be defult to "0". Amp is the cadence SQA-1 - it's a mono amp, but looking at the manual (kinda genaric) it looks like it may have a "HI-pass - Low pass" switch, needs to be LOW.

[chpthril]

What's the rest of this wall look like up behind the helm, where we cant see in the pic? if it goes up to the windshield, then that's where you need to mount the sub, forget the box. Youve got access to the back side through the storage door, shoudnt be hard to get a wire dropped in there

[tige']

Thanks for all the replies.

Where Mike has the X that is where the sub is (before picture). I have the wires there already, below is the after install pic (hopefully, if I attached it correctly!).

I was going the direction of adding a port or removing the side panel in Phil's thread but for some reason we went away from that. Well, I just removed the entire side panel and it did help... There isn't nearly as much rattle as there was and the sub can now take a lot more power.

However, and it is still hard to explain, but it sounds like the sub is sucking air rather than pushing it (I know it is supposed to do both) but it doesn't doesn't sound right. It hits real tight and quick. Maybe I am expecting too much or just don't know what it is supposed to sound like?? A 12" sub would be nice but I don't think I have the height for it.

I have tried numerous settings. I have had the crossover range set all over the place but depending on the music and whether it is a Ipod tune or a CD it really sounds a lot different.

A few more questions:

1) What is the difference between the amp gain and the Bass EQ DB Gain adjustment? I think I understand the amp gain but how is it different than the EQ gain.

2) Should I expect the sub to sound different whether it is wired in phase or out of phase (+ & - switched) IF it is the only speaker going (RCA's pulled on the other amps)?

I think I am going the correct direction. I went out this morning and bought the MDF but I am already happier with it just removing the side panel so I haven't started cutting anything yet.

Clarion head unit is maxed out at 6 (and I have tried lower settings). Amp is set at Low pass. I have amp gain setting, crossover setting, Bass EQ db setting and a wired remote db adjustment.

To check resistance to I just basically check across the speaker terminals and the speakers wires (with them disconnected)?

Thanks for all the help!!

[chpthril]

Thanks for all the replies.

Where Mike has the X that is where the sub is (before picture). I have the wires there already, below is the after install pic (hopefully, if I attached it correctly!).

Yes, but in a box. Dogbert and I are talking about literally cutting a hole where the "X" is, or in the 90* portion of the wall that cant be seen in the pic, and mounting the sub there..........no box at all, just a baffle board (the wall the sub is mounted to. See pic below (same wall, but diff yr/model boat)

I was going the direction of adding a port or removing the side panel in Phil's thread but for some reason we went away from that. Well, I just removed the entire side panel and it did help... There isn't nearly as much rattle as there was and the sub can now take a lot more power

However, and it is still hard to explain, but it sounds like the sub is sucking air rather than pushing it (I know it is supposed to do both) but it doesn't doesn't sound right. It hits real tight and quick. Maybe I am expecting too much or just don't know what it is supposed to sound like?? A 12" sub would be nice but I don't think I have the height for it. .

Check the wire for proper phase, both at the amp and sub. + to +, - to -.

I have tried numerous settings. I have had the crossover range set all over the place but depending on the music and whether it is a Ipod tune or a CD it really sounds a lot different.

Start with the H/U's EQ with everything flat or set on 0 in other words. Bass-boost on the amp should be at it's lowest point for now. Filter set to Low=Pass as indicated, Cross-over control set between 50-80Hz's. Is the gain set correctly (i'm sure you've done that, but gotta ask ) If it doesnt sound good with a variety of music, something is wrong.

A few more questions:

1) What is the difference between the amp gain and the Bass EQ DB Gain adjustment? I think I understand the amp gain but how is it different than the EQ gain.

The amp gain is for matching the amp to the H/U's line voltage output. The Bass Boost is used to set the tone to your personal pref.

2) Should I expect the sub to sound different whether it is wired in phase or out of phase (+ & - switched) IF it is the only speaker going (RCA's pulled on the other amps)?

Yes, but may not be as noticeable as if you had 2 subs with one wired in-phase and one out.

I think I am going the correct direction. I went out this morning and bought the MDF but I am already happier with it just removing the side panel so I haven't started cutting anything yet.

Clarion head unit is maxed out at 6 (and I have tried lower settings). Amp is set at Low pass. I have amp gain setting, crossover setting, Bass EQ db setting and a wired remote db adjustment.

To check resistance to I just basically check across the speaker terminals and the speakers wires (with them disconnected)?

Thanks for all the help!!

[/QUOTE]

I wouldn't rebuild the box just yet until you are sure that's the problem and not a bad component or setting.

Yep, with the sub's wires disconnected from the amp, put one meter lead on one wire, and the other lead on the other wire. If you see an out of range reading, then go to the sub, disconnect the wires and check the sub terminals - if reading is correct, problem is wiring, if reading is still out of range, problem is sub. High reading = poor connection, broken wire, bad coil winding. Low reading means short in coil or sub leads.

[tige']

I guess I am not really following what you are saying about the location. The pictures don't give real good views. But where the X is is the floor, it is at an angle but it is the bottom of the boat so I can't cut a hole there.

I tried to upload the "after" picture but it keeps telling me I already have it in the other thread so I can't attach it. I even tried changing the name. If you click on the link and scroll down you can see it.

http://www.tigeowners.com/forum/show...?t=8875&page=2

I added the front panel and the sub is in that. There was a side panel (on the 90* side to the right you can't see) and that was the panel I removed earlier today (and talked about removing in Phil's post). That seemed to reduced the vibration and rattling so I can run more power to the amp now. It is better but I think something still isn't right.

I have tried running the sub both in and out of phase - I don't really notice a lot of difference either way.

OK>>>>>>> I just went out and put the Ohm Meter on the speaker (with the wires disconnected) and got 4.2 to 4.3 ohms. BUT...If I understand you correctly I can also do this to the amp speaker connections and should also get 4.0 ohms??? Is this correct??? I assume this is with it off?? Please elaborate because I am not getting that...

[chpthril]

OK>>>>>>> I just went out and put the Ohm Meter on the speaker (with the wires disconnected) and got 4.2 to 4.3 ohms. BUT...If I understand you correctly I can also do this to the amp speaker connections and should also get 4.0 ohms??? Is this correct??? I assume this is with it off?? Please elaborate because I am not getting that...

Yes, reattach the wires to the sub and remeasure.....it should be about the same, maybe a few hundreds of an ohm higher as you have added in a length of wire. This step is checking the integrity of the whole circuit.

I guess I'm having a hard time understanding where the sub is. In the after pic, it looks like there is a box in the floor in front of the 45* wall I X'd in the pic above. I understand the angled wall may be floor, but what is above that that cant be seen in the pic? Is there a wall extending 90* behind the helm from the angled wall?

[tige']

Here are some more pics. A front view without the sub mounted and another from the side with the panel removed.

I mis-understood what you were asking to measure. I was checking the speaker terminals and then the amp terminals, both without the speaker connected. The speakers is 4.2 to 4.3 and with the amp connected the speaker is about 4.3. So I should be OK there...

[chpthril]

Here are some more pics. A front view without the sub mounted and another from the side with the panel removed.

I mis-understood what you were asking to measure. I was checking the speaker terminals and then the amp terminals, both without the speaker connected. The speakers is 4.2 to 4.3 and with the amp connected the speaker is about 4.3. So I should be OK there...

Got it now, that 2nd pic does it., there is no wall extending up from the angled floor. If it where me, I would see if I could install a wall there, and make it he baffle board (face) for the sub! Just a thought.

You want to check the sub and the wires, not the amp terminals. See if this diagram makes sense

[tige']

There is enough of surface area to use the side panel for the mounting plate. It is triangular shaped and wouldn't be tall enough to get the sub in it.

Above it, is the closet and I don't want to give that space up. Plus I think it would rattle the cabinet door on the other end really bad if I had it in there.

What are the 2 rectangles in your last diagram?

[dogbert]

What boat do you have?

[philwsailz]

tige-

Were we able to gifure out if you thought the woofer was operating correctly?