Custom In-Wall Speaker Build

[nathank]

I was tired of looking at the old speakers taking up my precious floorspace. I really wanted some in-walls, but didn't want to pay big bucks for them. Then it hit me, why don't I just use my current speakers and build new cabinets. So that's what I did.

The walls in my shop are framed to be even with the front of the purlin that runs all the way around the building. This gave me a good 8 inches of depth for the cabinets. I built them 7.5 inches deep, and adjusted the height so the airspace would be the same as the old cabinets.

Here is what I started with. I have had these suckers for many years.

3/4 MDF

The new cabinets are taller, but more shallow than the old

Here is the final shape for the new cabinets. Notice the lip all the way around to give it a finished look, and allow me to screw to the two studs when I slide it in the middle.

Time to plan for speaker placement in the new cabinet

Pegboard can be an awesome circle drawing tool!

I got the router out and put an edge on the box to make it look a little nicer

Test fit!

Installed the speakers

And terminals

Cut a hole in the wall and trimmed the insulation. The insulation will be squeezed between the back of the box and the metal of the building. Hopefully it will keep any rattles out.

New cabinet in wall

3/4"

The other side was a booger, I had to move an outlet

Final with both cabinets in

You can tell in the last pic I just swept..

The large space at the bottom will accommodate a port (on order). The old boxes were ported and I have been advised to add a port to these.

Overall I am very pleased. You can tell a slight difference in sound quality from the old cabinets, but I think once the port is added it will be very similar. Also, the increased quality from them being up around earshot is a big plus!

UPDATE

Ports

 

[nightrain00]

Nicely done and I have to remember that peg board circle trick

 

[burger]

Wow! Those are great. What do you plan to do for grilles?

 

[e-tek]

Very nicely done!! When did you notice you needed a port? Are you going to set this space up as a theatre room? Will it take up any "working" or parking space?

 

[therealjakeg]

Nice Bob Vila.. Looks good

 

[nobrakes]

Nice build on the boxes, but why didn't you mount the speakers above by the Mustang and Yamaha banners pointing down? If you are worried about precious floor space why do you have a big screen tv in your garage?

 

[txhusker]

Thats a clean install and great idea

Looks like you did a lot of cleaning from when I saw it last!

 

[SOA-Nova]

The large space at the bottom will accommodate a port (on order). The old boxes were ported and I have been advised to add a port to these.

Overall I am very pleased. You can tell a slight difference in sound quality from the old cabinets, but I think once the port is added it will be very similar. Also, the increased quality from them being up around earshot is a big plus!

Was the old port a 4" ID ?. If so you could use a PVC type of tubing from the hardware store. If the old port was 4" ID x let's say 10" and you do not have that kind of depth in the new setup, cut a new port using some PVC tubing and have it the same inside diameter as the old one as well as to the same length plus the width of a saw blade (maybe plus 1/8") and then put it in a chop saw and cut in in half on a 45 degree angle. Rotate the one half 90 degrees to form an L shape and glue the joint together. Place the 45 degree cut to where the tube end inside the cabinet is away from the front or back wall of the enclosure. I've done this before on ports and the port length through the center of the tubing is the same as being straight. The biggest thing with a port is having the same internal air space as the last cabinet and then having the same port diameter and length. If your new enclosure is smaller or larger than the other enclosure then the port length will be a different value. If the diameter of the port is changed then the length will also have to be changed. Porting an enclosure is not a random thing with picking a particular size and just any length. There are charts online that help with these designs.
When I put in normal PVC ports in I cut a snug fitting hole in the enclosure wall and leave it a tad proud of the face surface and then after glueing it from the backside, sand the edge of the port flush with the panel surface. I then come back with some rattle can black and paint the inside of the port tube.

Looks good.

Jim

 

[nathank]

Wow! Those are great. What do you plan to do for grilles?

I think I am going to use the grilles off the old boxes. If I paint them and use the old grilles, it will look pretty sharp.

Very nicely done!! When did you notice you needed a port? Are you going to set this space up as a theatre room? Will it take up any "working" or parking space?

After I built the first one I stuck it in the wall and compared the sound to the other one. You could tell a very minor difference at normal listening level. Of course it intensified as it got louder. The ported cabinet just sounded a little better. After talking to some folks on the audio board, they said if these are setup for ported enclosures, to keep them that way.

Won't be a theater room, strictly a garage. We have all the surround sound stuff in the house. I just need some jams while I work.

Nice Bob Vila.. Looks good

Thanks man, I appreciate that.

Nice build on the boxes, but why didn't you mount the speakers above by the Mustang and Yamaha banners pointing down? If you are worried about precious floor space why do you have a big screen tv in your garage?

Good questions. I did originally put the speakers up on top of the purlin, but they were just too high, and they didn't look very good up there.

I literally LOLd when I read the question about the big screen. Excellent point! The TV was one of those things where I was in the right place at the right time. Who would turn down a free big screen? I think I am going to build a corner shelf for it though, and get it off the floor.

Thats a clean install and great idea
Looks like you did a lot of cleaning from when I saw it last!

Thanks! I was right in the big middle of that loft project when yall came by. It was a bit messy to say the least!

 

[nathank]

Was the old port a 4" ID ?. If so you could use a PVC type of tubing from the hardware store. If the old port was 4" ID x let's say 10" and you do not have that kind of depth in the new setup, cut a new port using some PVC tubing and have it the same inside diameter as the old one as well as to the same length plus the width of a saw blade (maybe plus 1/8") and then put it in a chop saw and cut in in half on a 45 degree angle. Rotate the one half 90 degrees to form an L shape and glue the joint together. Place the 45 degree cut to where the tube end inside the cabinet is away from the front or back wall of the enclosure. I've done this before on ports and the port length through the center of the tubing is the same as being straight. The biggest thing with a port is having the same internal air space as the last cabinet and then having the same port diameter and length. If your new enclosure is smaller or larger than the other enclosure then the port length will be a different value. If the diameter of the port is changed then the length will also have to be changed. Porting an enclosure is not a random thing with picking a particular size and just any length. There are charts online that help with these designs.
When I put in normal PVC ports in I cut a snug fitting hole in the enclosure wall and leave it a tad proud of the face surface and then after glueing it from the backside, sand the edge of the port flush with the panel surface. I then come back with some rattle can black and paint the inside of the port tube.

Looks good.

Jim

Jim, this is excellent information.

I was careful to make sure I had the same internal airspace in the new box as the old, but you are spot on about not having the depth for the port in the new box. It was actually on my to-do list to find a solution for this, but it looks like the solution came to me!

The old port was 4-5/8 ID by 7-1/2 long

Any idea what the new length would be if I changed the diameter to use 4" PVC?

 

[5Cent]

New length would have to be 8.671875 for same volume at 4" ID.

 

[nathank]

New length would have to be 8.671875 for same volume at 4" ID.

What about a 6" ID?

 

[5Cent]

What about a 6" ID?

Volume of cylinder is calculated as followed: Radius x Pi (3.14) x L

So first would have been volume of 54.459.

4" ID would mean a length of 8.6718

6" ID would mean a length of 5.7812

 

[Holedgr]

There is much more to 'tuning' the box than just adjusting the diameter of the port by doing a basic volume calculation.....but for what you are doin.....just fine. I would avoid goin as big as 6". The setup looks GREAT. Nova's input is excelllent. I think the extra effort will be worth it!!

-T

 

[ddawg16]

Good idea.....and nice job.

Thanks for posting....you gave me an idea....I don't have the wall space for speakers, but no reason I can't put some in the ceiling. Yea, I know, it's won't sound nearly as good...BUT....when you have the table saw going...it don't really matter....I just need noise for the quiet moments.

 

[geaugafletcher]

Counterintuitively, the larger the port diameter, the longer the tube must be. 5Cent's not on the money there...

Also be aware that the volume taken up by the port tube is accounted for when the box is designed - in other words, a bigger & longer port takes up more space from the box interior = different tuning. So keep the port as close to the same size as the original as possible...

The port tube doesn't have to be inside the speaker enclosure...as long as it connects the air inside the box with the outside air moved by the cones, you're ok. Remember to keep the box volume the same, though...

 

[5Cent]

Sorry guys, I'm not into speakers, just helping him maintain the same volume in the cylinder. These are garage speakers so no competition tuning needed

 

[nathank]

Yeah I doubt the port is going to make these suckers sound much different. There was only a very small difference in the sound of the sealed and ported enclosures.

I'll be moving my super sub out to the shop anyway, but that's a post for another day!

 

[IHI]

Contractor tip in tough times- cant find your compass for circles, and dont have pegboard handy??...

Sawzall blade. It already has the centering dot punched out that always the BB in the saw to hold blade in position, and with a fairely agressive tooth count there's ample notches to slip the tip of a pencil/pen into.

not a real knock the world off it's feet idea, just figured i'd throw it out there since we've used them on jobs from time to time instead of walking back out to the trucks to grab a compass.

 

[nathank]

Sawzall blade. It already has the centering dot punched out that always the BB in the saw to hold blade in position, and with a fairely agressive tooth count there's ample notches to slip the tip of a pencil/pen into.

Heck yeah, great tip!

 

[SOA-Nova]

When going to a larger diameter port the length WILL increase. Going smaller in diameter will shorten the overall length. Going too small can create whooshing noises and this is why some you need to run flared end types of ports or larger diameter ones.

Another option to is find out the area of your existing port (pi x radius squared) and this number can be changed to a height and width figure. Without doing the math on your setup taking a 4" diameter ID port you have (pi x radius squared) 12.57 sq inches. You could make a rectagular port with the inside dimensions of 3" x 4.19 but the length would remain the constant (round VS rectangular). If the 4" round port was 10" long then the rectangular one would also be 10" long.
Like I said there are online port calculators out there.

One more thing to add on this post is porting an enclosure CAN be more damage prone than a sealed enclosure. Basically frequencies below he tuning frequency unload the speaker and makes it act like it is just laying on the work bench and you can over extend the woofer cone more easily and can damage it. Speakers need to be in some type of enclosure so that the waves eminating off of the backside do not easily interfere with the waves coming off of the front side. Some speakers can be put into ported enclosures while others should not be used this way. It's all in the design of the speaker.

Jim

 

[Stargeezer]

Speaking of ports: It looks sort of like your pegboard is flat against the wall? Hard to tell-but don't see any fasteners showing for the stand-offs. Do you have space behind all the peg board ports?

Cool speaker install. You going to paint/seal the cab faces? I always have MDF get gooey after a many years if it isn't sealed from moisture.

 

[nathank]

SOA-Nova, I am going to research the rectangular port thing. I think this would be much easier than doing the round.

Stargeezer,
The pegboard is flat against the stud wall, so pegs can be placed in the holes that are between the studs. I hope that makes sense.

Yes, I am going to paint the new cabs. I'm actually going to paint all the pegboard and the cabs, and finish them with grilles. I also have corrugated metal for the bottom of the walls. The metal on wall bottom is becoming a theme on GJ!

 

[nathank]

Speaking of ports: It looks sort of like your pegboard is flat against the wall? Hard to tell-but don't see any fasteners showing for the stand-offs. Do you have space behind all the peg board ports?

Cool speaker install. You going to paint/seal the cab faces? I always have MDF get gooey after a many years if it isn't sealed from moisture.

I found this calc

http://www.2k4civic.com/portcalculator.html

When I put in dimensions of old cabs and port it says it was tuned to 78Hz. Does that sound right?? Sounds a bit high.

 

[Bevis]

good job, they look nice.

 

[rburke65]

That's a good idea IHI, thanks!

 

[SOA-Nova]

I found this calc

http://www.2k4civic.com/portcalculator.html

When I put in dimensions of old cabs and port it says it was tuned to 78Hz. Does that sound right?? Sounds a bit high.

I did some back work with figures on your link and I kicked in 2985 cu. in. for airspace with a 4.625 (4 5/8") diameter port 7.5" long and it came up to pretty close to 78Hz.

2985 cu. in converts to about 1.7 cu.ft. and using this calculator:

http://www.the12volt.com/caraudio/boxcalcs.asp

I kicked in a 4.625” port x 7.5” long with an airspace of 1.7 cu.ft. and the tuning frequency was 49.5Hz.

What is the airspace you have ?.

I’m thinking the link you have to is wrong with their math or I didn’t catch it at first but they want cu.in. for the airspace.

I’ve used the 12volt.com link and right below the calculator I was using for this reply they also have a calculator for rectangular ports. When I used the other figures of your findings of 78hZ with a 4.625” diameter port and 1.7 cu.ft of airspace the port was a tad under 1”.

Jim

 

[nathank]

I did some back work with figures on your link and I kicked in 2985 cu. in. for airspace with a 4.625 (4 5/8") diameter port 7.5" long and it came up to pretty close to 78Hz.

2985 cu. in converts to about 1.7 cu.ft. and using this calculator:

http://www.the12volt.com/caraudio/boxcalcs.asp

I kicked in a 4.625” port x 7.5” long with an airspace of 1.7 cu.ft. and the tuning frequency was 49.5Hz.

What is the airspace you have ?.

I’m thinking the link you have to is wrong with their math or I didn’t catch it at first but they want cu.in. for the airspace.

I’ve used the 12volt.com link and right below the calculator I was using for this reply they also have a calculator for rectangular ports. When I used the other figures of your findings of 78hZ with a 4.625” diameter port and 1.7 cu.ft of airspace the port was a tad under 1”.

Jim

I see what you mean. That calc I found looks to be quite a bit off.

I have 1.75cu/ft in this box. And using all the numbers I get the same 49Hz. So playing with the port calculator I think I can use these

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=260-480

and cut them down to 4.5 in

 

[SOA-Nova]

I see what you mean. That calc I found looks to be quite a bit off.

I have 1.75cu/ft in this box. And using all the numbers I get the same 49Hz. So playing with the port calculator I think I can use these

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=260-480

and cut them down to 4.5 in

I kicked in the figures of 1.75 cu.ft., 49Hz tuning frequency, 3.75" ID port into the below link and also the other one from the12volt.com and they both came up with 4.34" long. Cutting the ones from parts express down to 4.5" in length will be just fine.

http://www.carstereo.com/help/Articles.cfm?id=31

Now, not to throw more problems into the works but from the end of the port to the backwall of the enclosure I would think you would need it to be maybe 2" or more. If the end of the tube is too close to the back wall it can become a restriction.

Isn't this fun

Jim

 

[nathank]

I kicked in the figures of 1.75 cu.ft., 49Hz tuning frequency, 3.75" ID port into the below link and also the other one from the12volt.com and they both came up with 4.34" long. Cutting the ones from parts express down to 4.5" in length will be just fine.

http://www.carstereo.com/help/Articles.cfm?id=31

Now, not to throw more problems into the works but from the end of the port to the backwall of the enclosure I would think you would need it to be maybe 2" or more. If the end of the tube is too close to the back wall it can become a restriction.

Isn't this fun

Jim

Well if this was a competition sub box I would probably put more thought into it. I doubt it is going to make too much difference on these anyway, like I said there wasn't that much difference in the sealed and original ones. I'm going to use those PE ports and call it good.

There will be close to 2" behind the port, I think it will be ok.

 

[SOA-Nova]

I knew I had some pictures of the right angle ports I made:

http://rides.webshots.com/album/559298395ChsafL?vhost=rides&start=48

Jim

 

[Kona Cruisers]

why not a slot port.. I mean if it is a 12 inch wide box (interior) ..(assuming 16 inch on center studs... probally not. but still) a 12 by 1 (close enough to 12.5... ) simple to make.. just a thougt

 

[CarWashGuy]

Very cool, I like the pegboard as well. I'll be doing something similar in the coming weeks.

 

[nathank]

UPDATE!!!

I finally got around to painting these darn things. I also added the ports a while back. They really do sound just like the old cabs. I am pleased with the outcome.

 

[HAMAR]

Very, VERY nice job there

 

[nathank]

Very, VERY nice job there

Thank you!