The Sacred Measurement = speaker-related

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Oct 14, 2006
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Location
Manhattan, KS
Having read nearly every speaker install thread for an FJ80, I took the sacred measurement of 1 and 7/8 inches to heart and began to Google with "mounting depth: 1" as the final search. This resulted with the limited pool of 5.25, 6 & 6.5 inch dia. offerings having a mounting depth of less than 2 inches. As most everyone has come to realize, this mounting depth pretty much rules out using the OEM grills with component set-ups (separate woofer & tweeter); and offers a handful of coaxials (Pioneer & Eclipse) which have been mounted under the OEM Land Cruiser grills.

Owning a 97 LX450, I followed several LX450 installs with enthusiasm. However, in most every case, the original aim of keeping even the deeper Lexus grilles fell by the wayside somewhere in the install & I was greeted with a mfg.'s latest trend in speaker grille bling.

Determined to stay within 1 & 7/8 RULES!, and after years of enjoyment of a 5.25 component set in our FJ62; I resolved to find shallow-mount woofers.

Now CDT has released for 2008 new inverted-magnet 6.5 inch components, and I spent some time contemplating their 1.8 inch mounting depth. Then by chance, I found some discontinued Diamond Audio M551 5.25 components with a mounting depth of 1.79 inches, described as store demos on eBay & won them for $91 shipped.


THANX to the Lexus FSM & several posts on how to remove the door panels; I pulled one off. Then removed the four 10 mm hex-head screws holding down the OEM Pioneer woofer. To my surprise, the speaker's bracket didn't want to pull loose from the door, so I gave a good tug & my fingers slipped onto the rim of the speaker cone. Voilà, the speaker diaphragms pulled off in my hand!


Well, this LF speaker had been whizzing with a rattle compared to its opposite. Here's some clues:
Diamond M551.webp
removal.webp
interior copy.webp
 
Please keep us posted, I too would like to know the best speaker package for my 80 while keeping the OEM look.
 
i too have been researching what speakers to install in my factory locations. what i have decided on is the infinity reference series. they are not components, but should be a great improvement compared with the stockers in my 96 LC. they offer a couple speakers in the series that are built for shallow depth. i think the numbers are 6022si for the 6.25, and 5022si. i have not started this project, but it is what i had thought would work.:cheers: and keep us posted.
 
The Pioneer woofer has 2 diaphragms (black & tan) mounted on a central coil which drops into the gap seen in the center of the speaker's spider (I cut the two leads from the diaphragms for this pic.). In the last 11 years, these diaphragms had both separated from where they were each glued to the metal spider. The outer rim of the black diaphragm has a plastic ring which nests onto a raised rim of the spider. This ring is what my fingers grabbed onto & pulled the cone off.

I want to say that the word cone is an obvious overstatement of what this speaker actually has. If Baskin-Robbins gave out a cone this shallow even the kiddies would cry FOUL!

How a Speaker Works:

The current from the Head Unit, alternating at the same frequency as the sound waves that generated it, induces an alternating magnetic field in the coil. As the polarity of the magnetic field of the coil alternates, it is alternatively attracted to and repelled by the permanent magnet. This causes the coil to vibrate. The vibrating coil causes the attached cone shaped diaphragm to vibrate and reproduce the sounds generated by the original source.

Pioneer's diaphragms are nearly flat, & by using 2 of them gapped apart, it approximates a cone-shape. We've all tried flat diaphragms when we built Kazoos. LEXUS & Pioneer should have dubbed this exotic LX450 ultimate sound system the Kazoo-O-Woofer Component Sound System.

So on to bigger & better woofers! I used a small pry bar to peel the Pioneer's steel spider off the Lexus door, as the sponge gasket had stuck to the door. I unplugged the speaker & picked up a Diamond woofer & placed it into the door. Hmmm, although only 1.79 inches deep, there was no way it was going to mount. What gives?
too D deep.webp
 
The Sacred Measurement: 1 and 7/8 inches

Yes it's in the FAQ; it's mentioned in nearly every replacement speaker thread. There could only be TWO possibilities:

ONE: mis-measurement. Naw, it couldn't be that. Mudders are a-retentive on taking precise measurements of their FJ80s, whether metric or not. Then I recalled something my Mother-in-Law had once asked me:



Q: What do most men think this is?
MIL-spec.webp
 
Part Deux

A: Six Inches. :grinpimp::grinpimp::grinpimp::grinpimp::grinpimp::grinpimp:



No, they surely didn't eyeball it, they took precise measurements, right?

TWO: There's something different between LX450s & LCs, other than pink panties. So I began to investigate further.

I started with a hunch: what would distinguish an LX from an LC installation? I wandered down many lines of thought until I remembered: only available in 96 & 97. And then I took a guess that maybe The Sacred Measurement was only based upon earlier FJ80s. So what was different in 96 & 97?

The side door reinforcements? So I searched & found only 1 post mentioning the addition of side door reinforcements for 96-97 models. I think all those who succeeded in getting a 1 7/8 inches deep speaker under the OEM grilles were dealing with pre-96 FJ80s. Mr. T's engineers had placed side door reinforcements in the doors to increase passenger safety; and in the process moved the window track closer to the inner door panel.


So how deep a speaker could be mounted? Follow along as I attempted to find The Sacred Measurement: Déjà vu aka Part Deux

As a one-eyed wonder, I needed a method not prone to eyeballing, as my Mother-in-Law would point out. Couldn't get a tape measure behind the speaker & a look-see without removing the plastic barrier & even then I'd be eyeballing from an angle.

So I added depth to the OEM speaker spider & bolted it back down.

The guage indicates the following mounting depth for the Lexus / Pioneer TS-04097ZT/UC: 1 3/8 -> 1 6/8 inches. This limits you to a speaker with a mounting depth of 1 AND 3/8 inches; or 4/8 = 1/2 inch less mounting depth than earlier FJ80s. You could use or build spacer rings, but I think you'd be out of luck on retaining the OEM grills, even with the deeper Lexus grilles.
door reinforcement.webp
depth guage.webp
results 2.webp
 
Stay tuned

Stay tuned (PUN) for more perplexing LX450 speaker replacement musings =


If I have to give up the grilles, will I have to watch the front extension of the woofer under the door panel? Will the grill clear the side of the dash? And why the heck does so much of the OEM woofer fire directly into the dash? If the dash weren't there. I could get some really honkin' bass with the OEM diaphragms & a few spare FJ parts:





.
LC deep bass.webp
 
Last edited:
Speaker fit-not exactly oem

I mounted 5 1/4" Eclipse SE8335 speakers in my fronts b/c the Infinity 6022's I thought would have their grills crushed-after about 45 days, one of the eclipse started to sound fuzzy--even thought the depth was more narrow than the Infinity, they sucked out. They had more punch than the Infinity's now in but....here's pic of the Eclpise, I liked them but out w/ the old. The rear passenger doors are JL Audio 4", forget the model but like those alot. Should have jammed some larger JL's in the front. I ditched the factory deck to go w/ a Panasonic 7205 deck-it was a great deal. If you can find one on fleabay, do it. The new model is pricier and no new features. Cheers!
eclipse front.webp
 
i too have been researching what speakers to install in my factory locations. what i have decided on is the infinity reference series. they are not components, but should be a great improvement compared with the stockers in my 96 LC. they offer a couple speakers in the series that are built for shallow depth. i think the numbers are 6022si for the 6.25, and 5022si. i have not started this project, but it is what i had thought would work.:cheers: and keep us posted.

I have all of these plus some reference tweeters, a 10" sub and a huge amp sitting in my garage. I have NO clue when it comes to stereo stuff and no clue how in the heck I am going to install all of it. My wife did an exchange of her accounting skills in exchange for all the stereo stuff. All I need, I think is wire and a new head unit. Although I am seriously considering using a Mac Mini.
 
no idea if this will help you, but..

In my 80, I mde up an MDF spacer ring for the fronts, approx 8mm thick. I inserted it between the door card (pushing it out a couple of mm, but you'de never know), and the metal inner skin of the door. Drilled through to use the factory mounting screwholes in the metal - you obviously need longer screws than usual. Job done, gives you a decent mounting depth, and a very sturdy mount which helps the low end.

HTH - JB
 
JLBUK....... I am going down the route of fitting new speakers, fitting the 8mm spacer behind the door skin, what mounting depth did you get? also what speakers did you fit?
I am thinking of the Infinity 6022si in the front, they have a mounting depth of 1 15/16" has anyone else fitted these?
 
From what I can tell when I did a quick test fit, you would have to do some SLIGHT metal trimming on the door to make the 6022SI's fit correctly. BUT that doesn't mean there is another solution with these. Its just what I noticed at first glance and then gingerly re-packaged them and now they collect dust.
 
Hmmm, although only 1.79 inches deep, there was no way it was going to mount. What gives?

The depth allowance is ~1.75" at the bottom of the speaker slot and ~1.60" at the top of the speaker slot. This is due to the slant of the window channel - closer up top, further away down below.

With shallow mount speakers, this shouldn't be a big issue. You can just use/make a thin 1/8" MDF spacer.



You might need to widen the sheet metal in the door and widen the hole in the door panel to accommodate a larger speaker, but depth and front spacing wise, you should be fine.

For the grill, the stock one will work as some have done previously with 6.5's (only for slim speakers). With 6.5's, the mounting tabs of the stock grill are too narrow and must be removed. This of course means you have to find a new method to mount them. Some have used a heavy duty glue. The glue method should work fine, as long as you're not putting 50 watts out of the front speakers.

For non-slim speaker, the allowed maximum depth of a front speaker is really ~2.10" rear depth and ~1.00" front spacing. Here the ~1.00" will be the combination of grill + space + woofer throw + speaker frame + grill frame.

I have 6.5's (2.5" depth) in my rig. By arranging a rear depth/front spacing accommodation, they fit fine. Yes, I've lost the factory grills, but that's the compromise for better sound. I do plan on color matching them to the door panel like I did with the tweeter, which should help blend them in more.





If you have questions, just PM me. I've got a '97.
 
mkfour, what model speakers are those and are you powering them off your HU or a separate amp?

Those are the MB Quart Reference RUA's 6.5 front, MB Quart Reference RUA 5.25 in the rear. I think the 5.25 is pictured, but eventually the 6.5 went in. They were made a few years ago, who knows if they're still being made.









Since then I've upgraded to the regular MB Quart Reference line.
 
Here is a comparison shot of the slimline (RUA) vs. regular (RVF).

IIRC the RUA has a listed depth of ~1.75" and the RVF has a depth of ~2.5".



2.5" is too much, but the RVF MBQ Ref line has a magnet basket that I removed. This took off ~0.25". So now the depth needed was ~2.25" so I put a 1/8" spacer behind the door panel and one behind the speaker.





Pretty good speakers if you can still find them. You have the option to mount the tweeter separately or coaxially.





Keep in mind that many speakers will fit that are ~2.5" in depth, but you're going to need extra room for the woofer extension and grill. IIRC the total amount is ~3.25" from the back of the speaker to the side of the dash.
 

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