SLIGHT crease to inverted tweeter

[heboil]

It was bound to happen, but 17 years after getting these, I accidentally touched inside the inverted tweeter and left a slight crease. So... I now fear I have damaged it, but how would I actually know? It sounds the same to me, but again, I'm just shrugging. The speaker in question is the JM Lab Cobalt 816S. When I say slight, I do mean slight.

I have taken a picture to illustrate. I do have the matching center and surrounds as well. I was thinking... "if" anything was wrong, I could swap my tweeter from a surround to the main (or get someone that knows what they are doing to do it) if replacement is a no-go. I hope everything is as normal as ever, but just wanted to ask here.

Thanks.

 

[JSmith]

slight crease

Hey, it looks very minimal and I would expect near zero impact... you will need to measure to be completely sure. If you're not hearing a glaring difference, all is likely well though... don't stress.


JSmith

 

[Keith_W]

Take measurements.

1. Place your microphone about 1cm from the tweeter.
2. Do a REW sweep of the tweeter alone (restrict range from XO frequency - 21kHz)
3. Do the same for the other tweeter.
4. Compare frequency response, distortion, etc. Post the results here

 

[Beave]

I frequently see listings for used speakers with completely dented/crushed tweeter domes, and the ad says "no difference in sound!" I generally roll my eyes.

But in this case, that is so tiny, that I bet it's probably not even measurable with the Klippel NFS and is very very unlikely to be audible.

 

[heboil]

Microphone ordered.

 

[voodooless]

don't stress.

Microphone ordered.

I really doubt that it makes a difference. In any case, don’t do anything to it, it will likely just make it (look) worse.

 

[kemmler3D]

Looking at it, I agree it's hard to imagine it throwing off the sound appreciably, especially since you said you can't tell.

While you wait for the microphone you could run some sweeps one speaker at a time, and just listen. If you hear anything obvious, there's your answer. If not, I am still interested in seeing the measurements... I often wonder how much these little dents affect things.

 

[Penelinfi]

I wouldn't do anything for that tiny crease.
It was measured once that a small but noticeable (half width of fingernail) dent in a dome tweeter may affect some response around 9kHz , but not really enough to be audible.

If you ordered a microphone at least you can use it for room correction

 

[solderdude]

It sounds the same to me

Then it isn't damaged.
I would not worry about it as it is a textile dome.

Chances are the mic you ordered is magnitudes worse than what your speaker puts out.
Be careful with tones fed directly into the speaker.

You could do the following (which will cost you nothing).

Play a sweep (online sweep generators are easy to find) and play it at a low level starting at 1kHz.
Listen to the speaker at close range. Don't do this loud !!!!!

Listen to the sweep on both speakers in the same way. When you do not hear something 'strange' in the 'damaged' one compared to the good one there is nothing to worry about.

It is highly likely the tweeter will be fine.

 

[Beave]

Remember that Amir measured an NHT C-3, then it was pointed out that there was a ding in the midrange dome (a worse ding than this, for sure). So he obtained another sample with no dings and re-ran the measurements. Even the Klippel didn't find anything.

 

[heboil]

I really doubt that it makes a difference. In any case, don’t do anything to it, it will likely just make it (look) worse.

I'm actually not stressed. I can't tell a difference. I don't imagine a mic will pick up a difference. I was already planning on getting a mic for REW but this just pushed me a little quicker.

 

[voodooless]

I'm actually not stressed. I can't tell a difference. I don't imagine a mic will pick up a difference. I was already planning on getting a mic for REW but this just pushed me a little quicker.

Well, good to know you bought it for the right reasons. Enjoy the tinkering

 

[thewas]

I would not worry about it as it is a textile dome.

It unfortunately isn't, that model has a titan dome, Focals famous inverse domes were always from metal from what I remember.

Metal and general hard domes (plastic etc) are sensitive in creases as they create usually break up modes in the audio range which are easily measurable with a mic (and often even quite audible especially in sweeps depending on the on their frequency location and listeners age ).

 

[YSC]

it looked really minimal to me, and IIRC these minor creases mainly affect the breakup modes and SPL limit, if you arn't going anywhere near stressing them I would guess it have no practical difference, it might show up in say distortion % if you drive them really loud.

And IMO the only serious issue it will result is
when you have the gear acquisition syndrome in action and need a reason for your better half

 

[heboil]

I

it looked really minimal to me, and IIRC these minor creases mainly affect the breakup modes and SPL limit, if you arn't going anywhere near stressing them I would guess it have no practical difference, it might show up in say distortion % if you drive them really loud.

And IMO the only serious issue it will result is
when you have the gear acquisition syndrome in action and need a reason for your better half

I hope you are right

 

[DVDdoug]

You are likely to measure SOME difference, even if there was no damage. You'll probably measure a difference if you measure the same speaker twice. So then you'll still be asking yourself if the difference is caused by the damage, or if you should be concerned about it.

 

[heboil]

Haha. I actually expected the same speaker would measure differently... I just didn't think that would contribute to my neuroses!

I have a sweep tone to try out later. Again, it is barely visible with the naked eye. I don't expect to hear a difference.

 

[YSC]

Haha. I actually expected the same speaker would measure differently... I just didn't think that would contribute to my neuroses!

I have a sweep tone to try out later. Again, it is barely visible with the naked eye. I don't expect to hear a difference.

or just get yourself convinced so you can upgrade to something you have been looking at for years

 

[heboil]

So, not to come as a shock to anyone, but I could not hear any difference between the sweeps of each speaker. I cannot hear above 15khz, so if it is different up there, I wouldn't know .

 

[antcollinet]

I think you've had generally good advice - except the advice to measure it - where I believe you'll be wasting your time.

It is a tiny distortion - very unlikely to make an audible difference PLUS you can't hear it.

Put the speaker covers back on, forget about it, and enjoy the music.