Replacing driver screws with brass screws

OP if it's the same density, sending a controlled tone you can hear the difference. This is just in stereo.. You can use just a tube and put it to your ear over the securements. Hit the tone, and listen... Tighten for a higher pitch...., Try not to back off.

Torque to TONE.... Old Ways...

Regards

Ok let’s look at it from the Old mechanics point of view. There are different types of brass. Some brass is slippery. :-)
The material is used as a normal wear part, it is used a LOT, in harsh environments. It has a different dampening effect depending where and how it’s used.
Brass securements with "double binding" washers won’t back out, IF they are torqued correctly...

When things are tight, they do not vibrate. IF thing are NOT tight they will BREAK!!! Ok you can add all the HOOP la you want..

IF IT’S tight, it won’t vibrate, if it’s loose it will...

The speaker rim (for the lack of a better name) needs to be
Secured correctly, with the correct binding head and locks
FLAT, not warped, torqued, in sequence and correctly.
SEALED, it CANNOT leak. AT ALL!
I’ve used Brass, Bronze. Copper, Stainless, Sheetrock screws (high carbon I reckon) internal HEX, Torex, la-te-da.

I use what looks nice, and I can torque to correct specs, easy Dudes and Dudettes!!

If it’s tight, and sealed, it’s dampened, and right...

What does that mean to me. ANSWER. The screws should NOT make a difference, if they are TIGHT.
LOOSE YES, Not torqued correctly, YES. Not torqued in correct sequence, YES.

Easy check, get a stethoscope, scope every screw UNTIL it has the same tone.. Just like tone tuning a spoke, wheel.

I bet YOU can hear better than you think, with a good tube scope, or a heart scope will work (10-20 USD) I use them all the time. STILL

LISTEN. You’ll see, or HEAR. :-)

Regards

MC, yes for our purpose, call it "rattle". If it's tight, (driver to cabinet) it is as ONE... If you listen with a scope say 2" from the screwface, note that tone and THAT SPOT (need to mark your measurement spots)
Torque, and listen.. If there is a "Rattle", that's real bad. The two pieces are NOT bound one to the other. Torqued properly...Recheck for TONE. Kinda see the difference?

We don't want a "given amount of movement" between the two pieces.
EX: Head to block, they move....

"No movement torque"...different kind of torque spec. This is the engineers job.... Not the mechanic... BUT, we'll fix it anyway. 

I'm not trying to come off as a "SQUINT" OK!!! Get to "squinty"
I can't keep up. :-)
  
We are looking to TUNE each securement to the same tone, via ear.
I suppose you could measure it pretty easy, if you need to, (for the measurement crowd). Then move your scope (pickup) over the securement. I TRY to get them all the same (tone) 2-4-6" away.
I try to TUNE/Torque so I don't have to do it again.

The above method will show you how BAD Big Box store 11-15 plywood really is..  HUGE voids... (internal wood rattle).  It will DRIVE you nuts, kind of noise. HARD to fix outside and look good, kind of NUTS... :-(

If you have a breakin (tone gen) for say 24-36 hours, recheck your securements. I've done it so many times, I can still hand torque to within 10 inch lbs of torque. Then see if it holds. It always does NOW..
If they come loose (never have), they NEVER come loose again. Silicone/thread locker/JB weld/binding head SS lock washers/nylock nuts/pinch nuts!!!

I use a (2-3) stage CROSS pattern torque too. 

OR Torque to tone if YOU want to. You know, learn something. :-)

MDF is easy to OVER torque... If it's too tight, it will warp the speaker rim and or pull the threads... If it's to loose, it will come loose again and pull the threads. When it's torqued RIGHT, and the screw HEAD is bound, it CAN'T move. If you can't get it tight enough, Half moon hardwood backers for the bass drivers. 3/8" thick 1-2" wide. Oak or Apatong. 60-160.00 usd PER driver.

Load 20 BASS drivers, gets spendy. You can make your own.  20.00 for 8", 30.00 for a 12", 1/2 red oak. few tools..

Regards

FINGER TIGHT? Sorry I'm rolling on the floor. That is a "I don't know how to tighten things" answer. I'm actually rolling on the floor... Me the dog and the rabbit. This is a builder (not engineer) answer to a poorly designed baffle, and driver securement system..

Ok this is how I see it happening. A driver manufacture measuring their projected driver response, looked good so they had a few thousand produces in CHINA. Then  found "MOUNTING" the driver changed the "Q" res to baffle. WHY? Forgot to figure in mounting the thing...AND
a soft baffle (my guess).

If anyone purchased a driver that couldn't withstand TORQUE, or designed one that way, it is FLAWED, simple.. If proper torque caused a driver problem, usually the baffle face is not flat. 
I have seen this EXACT same thing with neo planar (UPGRADE) added securements and properly torqued. VMPS neo 8 upgrade...To stop ribbon/planar distortion and usually material failure.

It sounds like they over torqued the basket, then under torqued, the basket.  Then settled for what they could keep the tightest the longest. But not tight, FOREVER... To keep the tonality the same day in and day out.... Can't keep torquing them up...OK

You have to torque and tighten EVERYTHING.... No exception. 

A moving torque method is good for a diesel engine (head to block).
But not where you want ZERO WEAR, You want ZERO wear in the driver pocket and the back face of the driver flange..
Finger tight.. Is that funny bunny, I'm talking to my rabbit (Junior)?
The Goat, I'm still pissed at because of the hat he ate...

Time to definitely feed the chickens, squint, squint. Palm to the head slap! Why do I even try to teach these chickens how to fix their own hen house.. silly me... Good to be the Rooster I guess.. :-)

BTW, now you see why a speaker sound engineer, is kinda low on the totem pole of engineers. It takes a mechanical engineer to fix the problem working with a GOOD sound engineer...to correct ALL issues with the box and drivers...or

maybe an OL wore out mechanic...OOPS, did I say that...

Regards

359/379 Peterbilt, aluminum nose. A true classic. I used to be in charge of 118 359s, and 26, 379s.. That puts a date on me for sure.. All Cummins power. 

Then I went HEAVY duty..

Regards