Is diffraction limited to tweeters

newlash09

Iam deaf at the ears, but way more dumb in between
Wammer
Aug 10, 2018
3,379
3,333
183
45
India
AKA
Y.Manohar / mike
HiFi Trade?
  1. No
I remember posting a thread almost a year back, about the "diffraction be gone pads".

Since iam coming to the end of my vacations. Thought I'd take up something easier to faff with. I've got a roll of acoustic felt and some car vibration damping sheets to start with. And before I go smearing my speakers with felt and glue, thought I'd check, why is diffraction only mentioned in conjunction with treble. I would guess the same principle of sound travelling on the front baffle, should also apply to mid range and bass drivers. I do vaguely remember it being something to do with baffle width and height vs the wave length of the frequency. Any guidance if trying felt on mid range drivers will also work, will be very helpful. Thanks

 

MVJ

Wammer Plus
Wammer Plus
Apr 9, 2020
20,457
42,382
198
HiFi Trade?
  1. No
😲😲😲😲😲

Now Then!!!!!
Step away from the keyboard turn around & go to the kitchen make yourself a hot beverage of your choice grab the biscuit tin and head for the hifi hot seat. OK! now choose one of your favourite records put it on then sit drink eat. REPEAT!!! this process until the daft idea to cover your speakers with felt, carpet, or insulation goes away.

You have a bad dose of "Whatthehellitis" 

image.png

image.png

image.png

image.png image.png

 
Last edited by a moderator:

garn63

Wammer Plus
Wammer Plus
Mar 3, 2020
12,284
18,699
198
www.avfc.co.uk
HiFi Trade?
  1. No
Stop this and use your energies to study music. The musician, the story, the time it was made....and of course the fact of why you like it. It will bring far more pleasure, especially when listening & smiling about all the puffs of smoke we have chased before getting to this point ?  😀  👍

 
  • Haha
  • Like
Reactions: MVJ and newlash09

newlash09

Iam deaf at the ears, but way more dumb in between
Wammer
Aug 10, 2018
3,379
3,333
183
45
India
AKA
Y.Manohar / mike
HiFi Trade?
  1. No
The idea is to improve my existing DIY speakers, and learn something along the way :)

 
Last edited by a moderator:
  • Like
Reactions: Bokke and garn63

bobovox

Wammer Plus
Wammer Plus
Nov 21, 2010
1,283
1,325
193
HiFi Trade?
  1. No
Hi @newlash09 this may be if some help in understanding the basics of baffle edge diffraction and the relevance of the wavelength:

https://audiojudgement.com/speaker-baffle-design-and-diffraction/
 

I honestly doubt there will be much in the way of benefit from adding felt as well as a considerable aesthetic drawback. Only adding a significant radius to the arrises of the cabinet will affect the diffraction to any significant degree. 

 
  • Like
Reactions: newlash09

newlash09

Iam deaf at the ears, but way more dumb in between
Wammer
Aug 10, 2018
3,379
3,333
183
45
India
AKA
Y.Manohar / mike
HiFi Trade?
  1. No
Hi @newlash09 this may be if some help in understanding the basics of baffle edge diffraction and the relevance of the wavelength:

https://audiojudgement.com/speaker-baffle-design-and-diffraction/
 

I honestly doubt there will be much in the way of benefit from adding felt as well as a considerable aesthetic drawback. Only adding a significant radius to the arrises of the cabinet will affect the diffraction to any significant degree. 
Thanks for sharing that sir :)

Will go through it now.

 

Rothwell Audio

Wammer
Wammer
Mar 23, 2016
347
254
48
Lancashire, UK
AKA
Andrew
...why is diffraction only mentioned in conjunction with treble. I would guess the same principle of sound travelling on the front baffle, should also apply to mid range and bass drivers. I do vaguely remember it being something to do with baffle width and height vs the wave length of the frequency. Any guidance if trying felt on mid range drivers will also work, will be very helpful. Thanks
The size of a typical front baffle, the frequencies involved and the effectiveness of felt means that it's only feasible to tackle high frequency diffraction.
The wavelength of sound at 1kHz is about 1 foot, and at 10kHz is about an inch (roughly), so anything that's going to be effective below 1kHz has to be bigger than 1 foot - and a 1 foot radius on a cabinet edge isn't really possible unless the cabinets are enormous.
As for absorbents, a piece of felt 1 or 2 millimeters thick is only going to be effective well above 1kHz.
Btw, BBC LS3/5As had a square of felt round the tweeter.  Seems like a good idea.  However, the cabinet had a lip round the edge - surely a bad idea?

Did you experiment with felt?  Did you notice any difference?  I wouldn't bother with the damping material - that's for a different issue.

 

newlash09

Iam deaf at the ears, but way more dumb in between
Wammer
Aug 10, 2018
3,379
3,333
183
45
India
AKA
Y.Manohar / mike
HiFi Trade?
  1. No
The size of a typical front baffle, the frequencies involved and the effectiveness of felt means that it's only feasible to tackle high frequency diffraction.
The wavelength of sound at 1kHz is about 1 foot, and at 10kHz is about an inch (roughly), so anything that's going to be effective below 1kHz has to be bigger than 1 foot - and a 1 foot radius on a cabinet edge isn't really possible unless the cabinets are enormous.
As for absorbents, a piece of felt 1 or 2 millimeters thick is only going to be effective well above 1kHz.
Btw, BBC LS3/5As had a square of felt round the tweeter.  Seems like a good idea.  However, the cabinet had a lip round the edge - surely a bad idea?

Did you experiment with felt?  Did you notice any difference?  I wouldn't bother with the damping material - that's for a different issue.
Thanks a lot for sharing the above sir. I fully concur with what your goodselves have mentioned. So I have to rethink my plan again I guess :D

 

Latest posts

Forum statistics

Threads
113,444
Messages
2,451,263
Members
70,783
Latest member
reg66

Latest Articles