New helm subwoofer encloser design help for malibu 247

[rjones]

Hello Crew I was hoping you all could give me some guidance on a new helm subwoofer enclosure on my 247. I finally got irritated and got the old box out. It was a crappy job to say the least whoever constructed the old box. It was around a 2 cf sealed box for a kicker 15" L7 stuffed with the white "stuffing" people use to try and mimick more air space. It turned out this box wasnt "sealed" at all. When i got the box out the seams had ripped apart where glue was used but no wood screws. No wonder it never really sounded right haha.

So onto the present......my boat is in torn apart and I am trying to figure out a new ported box design to hold a 15" RE audio XXX v2D2. Could someone help guide me in the right direction to go? I was planning to use cardboard to mock up a design and go from there but figured I should ask you all for tips and tricks.

[Ndawg12]

Isn't that 15" sub gonna want 3.5-4cf? That will be tough. I had a 15" RE in the same 2cf closure and it slammed in my vRide. Might fix and coat or replicate what you have.

[rjones]

Ya it is definitely going to want 3.5+ especially ported but there is room as proven by nryan2001 in his old XXX build thread http://www.themalibucrew.com/forums/index.php?/topic/36524-247-subwoofer-project/ . Actually that's kinda where I am going to start with the box design and kind of re-work it to my touches.

[waldito]

I have built 3 ported boxes to fit 15" subs for 3 different wakesetters every boat was a little different, But the one thing they all had in common was a lot of compound angles! I managed to get 3 cubic feet plus the port which was the minimum ported cubic footage for the subs I used. Here is a link to my latest boat that I did it has a few pics of the sub box, but unfortunately i didn't keep any of the dimensions, But i do recommend trial and error with cardboard. hope that helps.

http://www.themalibucrew.com/forums/index.php?/topic/50863-247-stereo-build-rgbs-and-lasers/

[rjones]

I have built 3 ported boxes to fit 15" subs for 3 different wakesetters every boat was a little different, But the one thing they all had in common was a lot of compound angles! I managed to get 3 cubic feet plus the port which was the minimum ported cubic footage for the subs I used. Here is a link to my latest boat that I did it has a few pics of the sub box, but unfortunately i didn't keep any of the dimensions, But i do recommend trial and error with cardboard. hope that helps.

http://www.themalibucrew.com/forums/index.php?/topic/50863-247-stereo-build-rgbs-and-lasers/

Thanks for making me remember that thread from last summer! I actually commented on it about your box design because I was going to re-design my box and keep my L7 but I decided to re-design and go with the RE Audio 15" XXX v2d2. I actually got it ordered yesterday and a new WS-420 EQ. I am going to need to get as close to 4 cf as I can with the XXX so it looks like I will be playing around with alot of cardboard in the near future!!!!

[nyryan2001]

rjones- have you considered calling Scream Marine and ask them to repeat my 4cf box build? Chances are fairly high i would think they will have a 247 in their shop over the next couple months.

Vendors on here would consider me a cheap bastard, but I would pay up to $500 for an exact fit perfectly tuned and spec'd box like I had in my 247 in those pics. The only thing I would change is my tuning freq. I had it at exactly 32hz. A tad low, I would do 35hz and as flat of a response as possible to perform well from 28 to100hz.

One other consideration not seen in the pics is we had to cut that lower vinyl portion, by the cup holder and placard by the driver's right foot back approx 2-3" to achieve that big of a box. I am 6'1", still never came close to hitting my knees.

[Brian Young]

rjones- have you considered calling Scream Marine and ask them to repeat my 4cf box build? Chances are fairly high i would think they will have a 247 in their shop over the next couple months.

Vendors on here would consider me a cheap bastard, but I would pay up to $500 for an exact fit perfectly tuned and spec'd box like I had in my 247 in those pics. The only thing I would change is my tuning freq. I had it at exactly 32hz. A tad low, I would do 35hz and as flat of a response as possible to perform well from 28 to100hz.

One other consideration not seen in the pics is we had to cut that lower vinyl portion, by the cup holder and placard by the driver's right foot back approx 2-3" to achieve that big of a box. I am 6'1", still never came close to hitting my knees.

Scream Marine's promo boat is a '08 247.

http://www.waterskiamerica.com/new_vehicle_detail.asp?veh=56937&pov=3885530

[rjones]

rjones- have you considered calling Scream Marine and ask them to repeat my 4cf box build? Chances are fairly high i would think they will have a 247 in their shop over the next couple months.

Vendors on here would consider me a cheap bastard, but I would pay up to $500 for an exact fit perfectly tuned and spec'd box like I had in my 247 in those pics. The only thing I would change is my tuning freq. I had it at exactly 32hz. A tad low, I would do 35hz and as flat of a response as possible to perform well from 28 to100hz.

One other consideration not seen in the pics is we had to cut that lower vinyl portion, by the cup holder and placard by the driver's right foot back approx 2-3" to achieve that big of a box. I am 6'1", still never came close to hitting my knees.

nyryan - I planned on calling them later today to actually discuss some options. As much as I love to tinker, etc. it really takes a tole on my back after laying awkwardly for a few hours messing with the boat. Sooooo if I could actually have them fabricate the box to where I could slide in a "plug n play" box that would be the way to go instead of building something myself.

On another note my WS-420 should be here today so I started taking apart my amp wall and re wiring everything. It is a straight up mess behind the wall to say the least. So with the 420, which RCA outputs should I use off the black box to the main RCA in on the EQ? I have also been scratching my head about how to split the outgoing RCAs from the EQ for my tower speaker amps. I have two amps (arc audio XD80.4s) running 4 - REV 8's and they have two RCA inputs for each amp. So does this mean I will have to split the RCA coming from the EQ into two more pairs of RCAs? One more questions for the EQ, I've heard people do power ground runs all the way back to the home battery and some using the terminal strip under dash. Which is the correct way to power to the EQ?

I am glad I started this proejct early this year because it will take a few weeks (for me anyways) to get everything wired properly.

Edited February 20, 2015 by rjones

[MLA]

RJones,

You can use either the front or rear RCA outputs to the EQ's input, just make sure the fade and balance are centered.

How ever you have the RCA's split to your dual tower amps, leave that as is as the amp, All that will change, will be the source will come from the EQ's tower output instead of the head-unit.

The important thing is to make sure all the audio share the same battery reference. I prefer to draw the head-unit and EQ B+ from as close to the amps as possible.

[nyryan2001]

Rjones.... you have two XDI804s?? They have line outs. no splitting necessary.... 1ft RCA out of the first right into the second?/

[rjones]

MLA - thanks for the input. I wasnt sure which RCA's to use going to the EQ main in that helps.

Ryan - Thats what I figured as well but these amps have a "front" and "rear" set of inputs for RCAs. I am still trying to decipher how the person before me installed everything but for some reason he split rca lines going into the front and rear RCAs on my XDI804 amps to the left in the pic. Heres a quick pic of the setup before I started unplugging things maybe you all can figure out

Edited February 20, 2015 by rjones

[MLA]

With that amp in bridge mode, you will need to occupy all 4 rca inputs on each amp. As for the single RCA pair coming in from the EQ, I would split it, rather than use the output to jump to the 2nd amp. This insures each amp gets the same line level since they are doing the same job.

[nyryan2001]

The problem here is he needs to go from 2 RCAs to 8 just for the tower amps. You are splitting 1 RCA to 4... Twice.

Rjones, highly suggest you look into a set of line drivers to get those 8 RCAs back up to where they need to be. Put one line driver for each of those tower amps.

[Murphy8166]

Audio control matrix

[rjones]

The problem here is he needs to go from 2 RCAs to 8 just for the tower amps. You are splitting 1 RCA to 4... Twice.

Rjones, highly suggest you look into a set of line drivers to get those 8 RCAs back up to where they need to be. Put one line driver for each of those tower amps.

So the signal really does drop off a lot when split a few times? The thing is I will have to split the RCAs going to my Rockford fostgate amp for the cabin speakers as well. What type of line driver would I use for the cabin/tower RCAs out of the EQ? Also, where do you install these line drivers? EQ should be here Monday so I'm going to get it wired up and get my 8 channel RCA line ran.

I'm making some headway on getting the wiring cleaned up and still trying to decide on what to do for a sub amp for the 15" xxx. I have an old Orion 2500d but if I remember correctly it has some sort of issue going into protect mode.

Edited February 22, 2015 by rjones

[MLA]

Last I checked, the WS-420SQ was a line driver

So the signal really does drop off a lot when split a few times? The thing is I will have to split the RCAs going to my Rockford fostgate amp for the cabin speakers as well. What type of line driver would I use for the cabin/tower RCAs out of the EQ? Also, where do you install these line drivers? EQ should be here Monday so I'm going to get it wired up and get my 8 channel RCA line ran.


I'm making some headway on getting the wiring cleaned up and still trying to decide on what to do for a sub amp for the 15" xxx. I have an old Orion 2500d but if I remember correctly it has some sort of issue going into protect mode.

The EQ you are installing is a line driver. So in reality, you are bumping the in level from the 2V head-unit level that was feeding the amps. If i am understanding correctly, nothing about the amps is changing, just the addition of the EQ/Line driver?

IIRC, you do not need to Y the RCA to that in-boat amp. It will pass through to all chnls with only a single pair of RCA.

.

[rjones]

Last I checked, the WS-420SQ was a line driver

The EQ you are installing is a line driver. So in reality, you are bumping the in level from the 2V head-unit level that was feeding the amps. If i am understanding correctly, nothing about the amps is changing, just the addition of the EQ/Line driver?

IIRC, you do not need to Y the RCA to that in-boat amp. It will pass through to all chnls with only a single pair of RCA.

.

Ya that's my understanding is that the EQ is a driver itself. I wasn't sure if I needed additional drivers since I'm splitting it a few times though. The guy before me had the inboat amp wired with 4 RCAs going into the front/back RCAs on the RF amp. It may work with only one pair and actually I hope that is true to save another splitting of the incoming RCA signal.

[nyryan2001]

Well let's assume the 420 does 6v per channel x2 RCAs out.

Splitting 1RCA into 4 twice

6v x 1

3v x 2

1.5v x 4

Not sure if this is exactly what happens as you split, or I'd the 420 even provides 6v at say 50% volume, but Not ideal to have 1.5v pre amp on the towers where you need sq the most. You'll have to gain up to compensate and introduce noise and lower Sq.

[MLA]

Well let's assume the 420 does 6v per channel x2 RCAs out.

Splitting 1RCA into 4 twice

6v x 1

3v x 2

1.5v x 4

Not sure if this is exactly what happens as you split, or I'd the 420 even provides 6v at say 50% volume, but Not ideal to have 1.5v pre amp on the towers where you need sq the most. You'll have to gain up to compensate and introduce noise and lower Sq.

Why will he need to gain up as you say? He's going from head-unit only to EQ/Line driver, so the gains should be coming down.

[rjones]

For now I am just going to install without a line driver and see how it sounds. I think i should be fine but if I find myself having to bump my gains up quite a bit I will re-evaluate with a line driver like the audio control matrix. Dang weather slowed down my shipment for the EQ so it should be here tomorrow (tuesday)hopefully and I will proceed to wiring it up and then update you all with my progress. As for the power, ground and remote wires.....I plan on sharing the positive and ground leads off of my RF amp for the in boat speakers. I will share the remote off of my remote relay for all other amps. Does anyone see an issue with this inducing noise into the system?

Edited February 23, 2015 by rjones

[Ridebutter]

Well let's assume the 420 does 6v per channel x2 RCAs out.

Splitting 1RCA into 4 twice

6v x 1

3v x 2

1.5v x 4

Not sure if this is exactly what happens as you split, or I'd the 420 even provides 6v at say 50% volume, but Not ideal to have 1.5v pre amp on the towers where you need sq the most. You'll have to gain up to compensate and introduce noise and lower Sq.

Voltage does not drop when run in parallel splits.

[rjones]

I just wanted to fill everyone in on my progress so here goes.....I have gotten all of my EQ, RCAs, and B+, -, remote wires installed/ran. This brings to me a wiring question for EQ. -Is it ok to run B+ and ground for EQ directly into terminals off of my Rockford Fosgate amp? I dont want this to create noise and then only have to take my amp board back off. The hardest part was digging the RCA cables through the hole in the hull under the dash but other than that everything went smoothly. Still trying to get everything tidied up and tied off before I put the amp board back up.

My 15" XXX should be here this saturday but now I have to come up with a design and build a box before it is of any use to me! One dilemma I am currently in though is do I just remove the heater core and try to sell it or relocate it? I am leaning towards just pulling out the heater and trying to sell the complete unit. Onto to progress pics......

[David]

Pre-amp voltage does in fact drop per device when it is divided/split into multiple terminations. These are high-impedance low-current applications as opposed to amplifier outputs for example. Ohm's Law isn't going to apply.

I wouldn't necessarily use the amplifier RCA pass-thru feature until I contacted the manufacturer and discovered whether these are buffered outputs or simply internally split. Here's why. If buffered, and when using both amplifiers for identical functions, the input gains of both amplifiers would then be set very differently to achieve the identical output voltage. I would be more comfortable with an external split in this case with the exact same input settings if both amplifiers are driving symmetrical loads and speakers. If used in different zones then the variance wouldn't bother me.

[rjones]

Pre-amp voltage does in fact drop per device when it is divided/split into multiple terminations. These are high-impedance low-current applications as opposed to amplifier outputs for example. Ohm's Law isn't going to apply.

I wouldn't necessarily use the amplifier RCA pass-thru feature until I contacted the manufacturer and discovered whether these are buffered outputs or simply internally split. Here's why. If buffered, and when using both amplifiers for identical functions, the input gains of both amplifiers would then be set very differently to achieve the identical output voltage. I would be more comfortable with an external split in this case with the exact same input settings if both amplifiers are driving symmetrical loads and speakers. If used in different zones then the variance wouldn't bother me.

Thanks for the explanation David on the gains and splitting RCAs vs internal splitting with "pass-thru". I went ahead and just split the incoming RCA signal from the EQ to my RF cabin speakers amp so that the RCA signals were split evenly and running parallel (i think this is parallel anyways) instead of using the 2 channel pass-thru feature. I am hoping to get atleast one battery re-installed to test everything.

Only thing I am still questions is my power wiring for the EQ. I ran my B+ to the power slot on my RF amp and the same with my ground to ground slot on RF amp. I ran my remote wire into my "turn-on" relay for my other amps. Do you see this causing interference and creating any sort of noise? I was going to make runs back to the actual battery but figured it was easiest just to share the B+ and ground off my RF amp.

Edited February 27, 2015 by rjones

[MLA]

I ran my B+ to the power slot on my RF amp and the same with my ground to ground slot on RF amp. I ran my remote wire into my "turn-on" relay for my other amps. Do you see this causing interference and creating any sort of noise?

Best way to prevent unwanted noise.