Must try MOD - Foam inside the stamped steel baskets - YES!

xschop · June 2023

ChrisD06 · June 2023

Thanks, @xschop
Very interesting mod... I assume this adds to the dynamat vibration damping ?

xschop · June 2023

It adds a small amount of extra vibration damping, but is specifically for rear cone reflection mitigation.

skrol · July 2023

Add me to the list. So I pulled the MW's from my RTA-11TL's as I had been meaning to JB Weld the magnets. I also had been meaning to remove some of the Sonic Barrier that I had put behind the MW's, making it 4"x4" squares. Then I recalled this mod and I happen to have some appropriate foam to use. I only placed it on the insides of the spokes and not the top or bottom edges. I also put a little on the tabs that stick down into the opening just for completeness. I was careful not to have the foam touch the spider or the rubber surround when the cone is moved through its path. Does it make a difference, probably but had to say with the other mods that I did. Bottom line, vocals sound better now than before I pulled the drivers out.

xschop · July 2023

Another F1 B-lister. Welcome aboard.

F1nut · July 2023

xschop wrote: »

Another F1 B-lister. Welcome aboard.

You must have missed the fact he removed an amount of BH5, which will make a HUGE difference compared to your hack idea.

ChrisD06 · July 2023

I wonder. Since I can't put BH5 in my M5JR+ because of the crossover being behind the midwoofer, could I use this armacell mod to kinda substitute the BH5? It obviously won't be as effective but would it work enough?

Gardenstater · July 2023

ChrisD06 wrote: »

I wonder. Since I can't put BH5 in my M5JR+ because of the crossover being behind the midwoofer, could I use this armacell mod to kinda substitute the BH5? It obviously won't be as effective but would it work enough?

The BH5 only works on reflections that have exited the basket and standing waves within the enclosure. If you read through this thread you will grock that the armacell inside the basket works on reflections that probably would have never even left the basket but would most certainly reflect back through the cone as distortion.

I'm not sure who you are asking but I would just give the same advice that I gave you before; ask people who have done it, not people who haven't done it and haven't heard it.

ChrisD06 · July 2023

Gardenstater wrote: »

ChrisD06 wrote: »

I wonder. Since I can't put BH5 in my M5JR+ because of the crossover being behind the midwoofer, could I use this armacell mod to kinda substitute the BH5? It obviously won't be as effective but would it work enough?

The BH5 only works on reflections that have exited the basket and standing waves within the enclosure. If you read through this thread you will grock that the armacell inside the basket works on reflections that probably would have never even left the basket but would most certainly reflect back through the cone as distortion.

I'm not sure who you are asking but I would just give the same advice that I gave you before; ask people who have done it, not people who haven't done it and haven't heard it.

I was just asking out in the open for any sort of input from anyone. I might give it a try, just need to grab some armacell or some open cell foam to put in there.

plastic_avatar · July 2023

I wonder if BH5 in 2x4 strips on the side walls would be effective in the jr?

ChrisD06 · July 2023

plastic_avatar wrote: »

I wonder if BH5 in 2x4 strips on the side walls would be effective in the jr?

No clue, would rather not do any experimental stuff and just go with stuff that's been tried and written in stone.

skipshot12 · July 2023

^ Totally agree and understand but, that’s how the tried & true mods came to be… trial and error.

I’m still so considering this.
Only thing my brain is keeping me from trying this is the 16 friggin MW’s 😬

ChrisD06 · July 2023

skipshot12 wrote: »

^ Totally agree and understand but, that’s how the tried & true mods came to be… trial and error.

Excellent point! The only issue would be how much foam I'd add. BH5 is pretty known, 3x3, 4x4, etc, and with this armacell mod you line the inside of the basket with it. But with adding it to the sides... what size should each sheet be? Trial and error would be really tedious...

xschop · July 2023

F1nut wrote: »

xschop wrote: »

Another F1 B-lister. Welcome aboard.

You must have missed the fact he removed an amount of BH5, which will make a HUGE difference compared to your hack idea.

You missed the fact that this inner-frame modification has ABSOLUTELY NOTHING to do with the BH5 modification.

bcwsrt · July 2023

I believe the point is he did that and removed BH5 at the same time and has no idea if the foam made a difference or not.

skrol wrote: »

… Does it make a difference, probably but had [hard] to say with the other mods that I did...

skrol · July 2023

The idea of reflections off the spokes of the basket kind of makes sense since we know there is reflection off the back wall of the cabinet. Even though I applied the foam to the spokes of the basket, I question if there is enough material there to really absorb the reflection very much. It is of no harm if it isn't interfering with the cone or spider movement, low (or no) cost and, as they say, everything matters. Removing the excess Sonic Barrier (BH5) likely did far more to improve the speaker over the way I had it.

Jazzhead · August 2023

When I first tried this mod on my old 12's I had listened for months with my speakers unchanged, using 1&1/4 Sonic Barrier to completely damp the outer drivers (the successful westmassguy comb filtering mod):

https://forum.polkaudio.com/discussion/173834/westmassguys-idea-employing-damping-to-mitigate-comb-filtering-and-lobing)

and a 4x4 piece behind the inner drivers (along with uncompressed polyfill behind both drivers). To my ears damping materials like Sonic Barrier and BH5 mitigate midrange "shoutiness", loss of composure at higher volume levels, and generally clean up what sounds like backwave slapping around inside the cabinet. The stuff is so effective that I can now casually hear the frequency difference between the two drivers (the idea behind the westmassguy mod). Gardenstater's driver basket mod is a different animal that removes "smear", and brings clarity - most noticeably with vocals. I have noticed it takes a bit more juice to reach the same loudness the speakers produced pre-mod. After several months I reduced to a 3x3 inch piece of Sonic Barrier and found that to be the best combo. I haven't noticed any reduction of bass, or loss of liveliness, but I also can't measure anything. My rig and room produce a lot of bass and I would trade some of it to keep the foam mod clarity. That said, my speakers are old, with a somewhat flawed design, so YMMV.

Gardenstater · August 2023

skrol wrote: »

The idea of reflections off the spokes of the basket kind of makes sense since we know there is reflection off the back wall of the cabinet. Even though I applied the foam to the spokes of the basket, I question if there is enough material there to really absorb the reflection very much. It is of no harm if it isn't interfering with the cone or spider movement, low (or no) cost and, as they say, everything matters. Removing the excess Sonic Barrier (BH5) likely did far more to improve the speaker over the way I had it.

I did it by itself with lots of ingrained aural memory of how my speakers sounded prior, ie. lots of time since the previous mod which I believe was a 6" x 6" square of BH5. Eva Cassady was the first listen and her vocals were cleaned up and I realized that "Live at Blues Alley" had lots cleaner reverb and it was clear that I was listening to somewhat distorted reverb prior. Further listening revealed that vocals that were very low level like background vocals often tend to be, became more discernible, as well as being able to decipher words to songs that I had been unable to, previously. Also, multiple singers and instruments were more separated and distinct. Very pleasurable.

You might go back in and do the area near the spider, between the spokes. Pretty significant amount of reflective area there.

Jazzhead · August 2023

Clarity relative to understanding lyrics, distinguishing instruments etc. reduces listener fatigue.

Gardenstater · August 2023

Try covering some aluminum flashing with some Armacell on one side and speak at it with a high tone of voice. Now flip it around and do the same thing. I hear a subtle difference. With two layers of Armacell still subtle but slightly more of a difference. It is more pronounced when you hold the flashing at an angle to a wall and do the test that way. In the speaker basket there are reflections back at the cone and there could also be transmissions through the steel that could have an audible effect as well. If they did not have an audible effect, then the constrained layer dampening material (Dynamat and others) wouldn't be audible. Also, I know you know this but have to point out that changing two variables at once and drawing a conclusion that what you hear is due to only one of them is a definite no no in science and engineering

Edit - how would the following experiment go if the 2nd tuning fork were covered with Armacell?

https://www.youtube.com/watch?v=aCocQa2Bcuc

gp4jesus · August 2023

Very interesting

xschop · August 2023

This is why you should also butyl-mat your drivers that have the magnetic shielding shroud attached to the magnet as well. It is just a ringing bell hanging off the back.

xschop · February 26

Bump for @inanortherntown.
Inexpensive yet very effective modification. Should be a sticky here.

odcics2 · February 26

Wonder how great an MW would sound modified to look like an early KLH woofer??
Very minimal reflections!

xschop · February 26

It would also increase the speed of the cone during lower frequencies, no?

inanortherntown · February 26

xschop wrote: »

Bump for @inanortherntown.
Inexpensive yet very effective modification. Should be a sticky here.

Thanks much! Will take a look

-Tony

odcics2 · February 26

xschop wrote: »

It would also increase the speed of the cone during lower frequencies, no?

It would allow the cone to follow the sound wave more effectively, decreasing distortion.
The reduction in back wave reflection would be helpful!
A good fabricator could make a large ring to hold the surround, 4 stilts, and a small ring to hold the magnet assy.
It would be a great experiment.

gp4jesus · February 26

Interesting…

One of the higher-end tire manufacturers, attempting to attenuate ~200hz road noise using a similar execution of foam on the interior

Hansvelton · March 3

Not against fun experimenting, but have to wonder, if this was a thing, would someone else not have know about it by now, I mean we have Kippel measurements for years, and not a single speaker manufacturer has ever employed this "Mod".......

Gardenstater · March 3

Do you know what everyone on the planet "knows" LOL?

Ask ya another question.......does CLD ie. Dynamat etc. on the basket work to clean up the detrimental effect of vibrations upon the clarity of the driver? Why didn't and don't you see manufacturers doing that?

Manufacturers have largely solved both of these problems another way, by going with cast baskets with minimal spoke area and ventilated designs behind the spiders.

Must try MOD - Foam inside the stamped steel baskets - YES!

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