Front Kick Speaker Box/Spacer Build

[Gary in NJ]

I often see the question "how do I mount speakers in my Z". I installed some new 5.25" co-ax speakers in my 240 today, so I though I'd chronicle the process.

My design goal was to install modern speakers without encroaching on the foot well area. That requirement calls for cutting into the kick panel to use the area behind the panel. The space behind the kick panel is limited to about 1-1/2" (it's actually 1-3/4", but there is a bolt head for the door bracket that takes up some space - you'll see it in a photo below).

Most 5.25" speakers sold today are 1-3/4" to 2-1/2: deep (when front mounting.) The speakers I purchased (Alpine SPS-500) are 2" deep. I could have built a spacer as thin as 1/2 inch, but I wanted some space between the speaker magnet and the body of the car, so I elected to build a 1" deep box (it's actually a spacer, but I'll cal it a box since it looks like a box when installed).

I didn't have a 1" thick piece of wood, so I made one by gluing a piece of scrap 3/4 x 6-1/2 molding (pine) that I had laying around to a piece of 1/4" MDF I had left over from another project. I used Tite Bond III and placed it in wood clamps for a few hours. I then drew the box shape (6.25 x 6.25) and located the center of the box.

These speakers require a 4-1/2" hole for mounting. Luckily, I happened to have that size hole cutter. It's a lot easier to cut those holes before trimming the board.

Here is a photo of a speaker and grill sitting on two of the cut-out boxes. Note that the tweeter on these speakers swivel. That keeps the high frequencies from driving directly into your ankles.

Here is the back-side of the box prior to the speaker being installed. I have marked the speaker and box for its location (right on this one) and its orientation. I did this to make sure I had the tweeter swiveled into the best position.

Here is the kick panel cut-out. That hole is about 3-1/2 wide - too small for a speaker, but just right for the magnet.

Here is a dry fit of the box. The four mounting screws were located and drilled in this step. I used a 3/16 bit on the box, and then used those holes as a guide to drill a 1/16 hole into the panel and the metal behind it. I used 3/16 x 1-1/2" sheet metal screws to attach the box to the panel.

I notched the backside of the box for the speaker wires. This will keep the box as flush as possible to the panel and will keep the wires from getting pinched.

Using 3M 77 spray adhesive, I attached some rat fur to the box and then relocated the 8 drilled holes (4 to attach the speaker and grill to the box, and 4 that attach the box to the kick panel) and opened up the 4-1/2 hole for the speaker.

Here is the speaker and grill installed in the box. Time to mount it in the Z.

Here is the completed unit installed. The box is completely unnoticeable when driving. It provides a low-profile installation, with high-profile sound. This is paired with a 6-1/2 powered 100W Bazooka (BTA6100) subwoofer in the hatch area. My Alpine head unit (CDE103BT) has a built-in cross over that I have set a 85Hz, the upper end of the sub and near the lower end of the 5.25 mid-bass/tweeters.

It sounds great and all works well together.

Edited June 28, 2010 by Gary in NJ

[OhDearAudrey]

This is a very nice write up, atm my speakers are in the doors but i have replacement door panels and was wondering where to relocate them to.

On a side note what is that knob above the hood switch?

[Gary in NJ]

Air vent.

[erectorset]

Gary: I could have saved you some money and certainly a lot of time. Three decades ago after I replaced my 2-speaker AM/FM Stereo Cassette with a 4-speaker AM/FM Stereo Cassette in my 1971 240Z, I purchased two 6" diameter recessed magnet type speakers. I removed the two access panels to the rear lamps located on the inside of the rear deck panel just below the hood latch. There is plenty of room in there for the recessed magnets. The bolt pattern on the 6" diameter speakers matched exactly the spacing of the two upper screws for the access panels. Using the same screws I attached the speakers (with two screws each) after running wires below the rear deck carpeting and the center console from the radio. The speaker covers mask the rectangular access panel openings so that there are no visible openings. My other two speakers are mounted on the vertical panel behind each seat. They are surface mounted boxes with built in tweeters and they face up at an angle. With four speakers my Z has plenty of sound for such a small cabin.

PS: I recommend any Howlin' Wolf cassette you can find.

[Gary in NJ]

The boxes cost nothing to make, and it was fun. In all it took about an hour to build and install.

I'm not a big fan of placing the HF behind me. With the speakers mounted that far back (and so close together), the sound stage is destroyed yielding poor stereo separation. With my installation, the tweeters are facing right at me, which is perfect. The mid-bass would work just behind the seats.

I do have my sub mounted as far away from me as possible. That gives the the bass the most even distribution.

[ktm]

I mounted mine in the exact same location. I opted for 6-in. Alpines with the adjustable tweeter. I have 3-way Pioneers mounted in the vertical riser behind the seats as well and MB Quartz tweeters in the two side vents.

[cbudvet]

Gary,

Does the speaker interfere with foot placement on the dead pedal? I was just curious if you found your foot hitting or rubbing against the speaker grill.

carl

[mlc240z]

Must........not..........cut........kick..........panel.......

If it was 1975, no problem, would have done it in a flash.

I'll keep looking for a solution.

Nice work, though!

[Zs-ondabrain]

here's a couple ways as well. As for the stock kick panel, I just copied it onto a peice of 3/16" MDF and put the stock panel on the shelf.

Dave

Edited June 29, 2010 by Zs-ondabrain

[Gary in NJ]

Carl, the box is so low profile that you don't even know it's there. There is no chance of the box interfering with the dead pedal. It sits a lot higher then you'd think,

Bart, since these aren't the original kick panels, there isn't anything sacred about them. Besides, it's not as if you'd uninstall the speakers. You might upgrade though.

Dave, I really wanted to give a spare-well sub a try, but the Bazooka powered tube was just too easy.

Edited June 30, 2010 by Gary in NJ

[Zs-ondabrain]

I Love the Bazooka tubes. I'm half tempted to put an amplified tube in the green Z as a good selling point. And they make for Great rear fill in these small cars. and the green Z already has 4 other speakers so it'll sound amazing, compared to the single speaker it came with.....

Dave