Possibly another shiny dustcap alternative

[LittleBitLouder]

I was at my local Napa the other day browsing around while waiting for my parts and saw something that made me think hmmmm. Little round blindspot stick on mirrors. They had them in 3" but I found 2" ones too at my local Ace Hardware. Extricated them from their plastic bezel and weighed them. 9.4 grams for the 3" and 4.3 grams for the 2" compared to a 3" mylar from a dead woofer @ 1.6 gram and a aluminum JBL style 3-1/4" @ 3 grams. Had a MCM 55-3231 8" I was doing testing on and decided to try the 3" on it. Centered it and ran a pencil around the mirror and put a decent bead of E-6000 glue on the line and put it in place with a valve lapper(wood handle with suction cups on the end). Well let me tell you I think it looks great! The sound however with this speaker is different. With a 150hz low pass coil it sounds good maybe a little less efficient because of the weight but with a bass heavy eq it bottoms out. Never did that before, probably also due to the added weight. Now without the crossover It sounds absolutely horrible! My theory is the mirror is resonating severely at about the 3000-5000hz and is down right painful at high volume. Sooo, with this speaker maybe because of the poly cone...perhaps a paper cone or maybe the 2" would have better results not sure yet, more testing is required. Just wanted to throw this out there knowing what a PITA shiny dustcaps are to find, Got a couple from fried woofers but don't have the heart to do dust cap- ectomy on a healthy speaker so always thinking of alternatives.

 

[redbenjoe]

i think its a great idea --thanks

for smaller --maybe a bike mirror will work

 

[Beosystem10]

Looks great as a dustcap, but can't see what possible use these would be for wing mirrors, given that they're convex, which would distort your view and create a false impression of distance between vehicles.

 

[Gluecifer]

Jiminy crickets! Amazing!

Just need to sort out the way to affix them I guess.

I'll be picking a few up myself for some experiments.

GREAT work, LittleBitLouder!



Rock On.

 

[devol-toni]

Interesting, thanks for sharing


John@ these convex mirrors are very useful. When you driving there is always a blind spot that you can not follow with the usual car mirrors. Their use is not important for the distance of the object rather than the existence of the object.

 

[redbenjoe]

yup . johm - DT is right-
these are just used as little stick-on to the main mirrors--and they are for momentary glances
to cover the blind spots

 

[Beosystem10]

I see.
(These are illegal to use in the UK, because they distort distances, that according to the Construction and Use regs though surprisingly, they're not a specific annual MOT failure point). I guess they'd serve a purpose for anyone whose neck had restricted mobility though, so couldn't do what our driving instructors all taught us to do: Look over the shoulder to check the "blind spot!"

But they do make great looking dust caps.

 

[im_alan_partridge]

What a great idea

And as for the blind spot issue, I think they can be used for towing and parking.

 

[Lasonic TRC-920]

2 questions:

What do they weigh and how are you going to affix them?

Nothing ad's BRAWN to a boombox like a big chrome center cap!

 

[redbenjoe]

same ? as chris --the weight would be the one negative factor-
i think these are all plastic with a mirror finish - not heavy glass-
but still - they be be too heavy ?

 

[Cpl-Chronic]

too much weight......looks awesome tho.....The problem with the weight is that it throws the design characteristics for the woofer out the window. Now, the center of the woofer has about the same inertia & mass as the rest of the diaphragm so that the coil motor action will flex the sides of the cone more & bottom out as stated & conversely affect the damping characteristics too so that the woofer will tend to stay in motion longer, after the initial signal has been spent, causing intermodulation distortion & muddy bass.....there's a very good reason the normal chrome caps are paper thin & weighing only 1 or 2 grams....If you tried to paste one of these mirrors to an original paper cone woofer, the paper would probably rip itself apart, as soon as you put some decent mid-bass volume through it....

Cpl

 

[LittleBitLouder]

CPL I agree, at 9.4 grams the 3" mirror is a no go, looks killer but the woofer isn't happy. The 2" mirror might be borderline at 4.3 grams but may work okay on a 6.5" to 8" retrofit newer speaker but not an original with dried out paper. The E6000 glue I used is holding strong on my test subject poly cone and should work well on a newer paper retrofit or replacement woof. Yes these are plastic, the the chrome is applied to the backside. Going to test the 2 incher soon, I'll keep everyone posted.

 

[Lasonic TRC-920]

CPL I agree, at 9.4 grams the 3" mirror is a no go, looks killer but the woofer isn't happy. The 2" mirror might be borderline at 4.3 grams but may work okay on a 6.5" to 8" retrofit newer speaker but not an original with dried out paper. The E6000 glue I used is holding strong on my test subject poly cone and should work well on a newer paper retrofit or replacement woof. Yes these are plastic, the the chrome is applied to the backside. Going to test the 2 incher soon, I'll keep everyone posted.

Thanks for the up date...

 

[check tha bass]

only question i have on these is,could they could effect the sound from the voice coil ?

 

[Beosystem10]

only question i have on these is,could they could effect the sound from the voice coil ?

too much weight......looks awesome tho.....The problem with the weight is that it throws the design characteristics for the woofer out the window. Now, the center of the woofer has about the same inertia & mass as the rest of the diaphragm so that the coil motor action will flex the sides of the cone more & bottom out as stated & conversely affect the damping characteristics too so that the woofer will tend to stay in motion longer, after the initial signal has been spent, causing intermodulation distortion & muddy bass.....there's a very good reason the normal chrome caps are paper thin & weighing only 1 or 2 grams....If you tried to paste one of these mirrors to an original paper cone woofer, the paper would probably rip itself apart, as soon as you put some decent mid-bass volume through it....

Cpl

 

[check tha bass]

oh sheet,sorry i try to read so fast some information doesn't go into my brain lol..and sorry to cpl for my ignorance,he answered my question before i even asked lol..

 

[Beosystem10]

No worries man, we all do that! As for our Cpl, he's good that way and his understanding of acoustic principles is very useful.

 

[riker1068]

I wonder if double mint paper will work? lol. I love the mirror look and Idea.

 

[metalhandbag]

Way to heavy but they look cool .