Use of Felt, and Speaker Alignment in an Optimal Cabinet.

[tvrgeek]

take the time to find natural wool felt. Any percentage of synthetic will not sound as good as 100% pure wool. The absorption of synthetic felt is not as wide band nor as uniform as that of natural wool.

McMaster Carr carries many thickness and densities of pure wool felt. It ain't cheap, but you "yous gets what ya pay 4"

 

[mistertrent]

Hey Oliver, thanks for the awesome long reply and help, I was just going over plans in Indesign, I drew up a scale drawing to find out the ratio I should use... and ended up with the following... the 0.707 does not work, but the 0.618 will fit.

An externally hosted image should be here but it was not working when we last tested it.

 

[planet10]

Every studio monitor I can see online just with a quick search on google, the mid/woofer and tweeter appear to be centered vertically,

Attached is a picture of the ProAc Studio 100. Many of their speakers offset the tweeter.

ProAc - perfectly natural

dave

 

[planet10]

Hi dave,

i would have preferred a vertical "in line" arrangement of
woofer and tweeter.

Since this is to be a nearfield monitor, with your 45 degree
arrangement one is free to put the speaker vertically or
horizontally and get similar dispersion in both positions.

Is this what you intended ?
Or just increase of asymmetry for the tweeter ?

45 degrees not fixed in stone, or even intended. I usually line up the outside of the tweeter bezel with the edge of the midwoofer (except that most of my speakers don't have tweeters 🙂). Gives a more compact vertical alignment with little effect on the horizontal, gives more assymettry for the tweeter to the edges, and gives more range of geometry with placement left or right and with toe-in.

dave

 

[mistertrent]

Here is another scale drawing where I have just calculated the woofer's distance using the 0.618 ratio from the top of the cabinet. Then placed the tweeter for a 140mm C2C. Looks better... but won't sound better?

An externally hosted image should be here but it was not working when we last tested it.

 

[mistertrent]

Attached is a picture of the ProAc Studio 100. Many of their speakers offset the tweeter.

ProAc - perfectly natural

dave

Offsetting a tweeter I do understand and I have seen before, in studio monitors, and other speakers, but offsetting the woofer is what I don't get.

 

[TheSeekerr]

Basically depends on how high you're crossing - diffraction is no big deal at low frequencies, so having a centred woofer doesn't usually matter.

 

[mistertrent]

2500hz... I think.

 

[planet10]

but offsetting the woofer is what I don't get.

Offsetting the woofer will (generally) reduce the ripple in the baffle step rolloff.

dave

 

[mistertrent]

mmm well, I am going to go to the garage now, and drill the holes. I will save the offset woofer idea for another set when I can actually test what offsetting does... later when I have real measuring equipment, etc... I just can't do something like, offset the woofer a certain amount without measuring it myself to see what will actually happen, I can see that other people do, and have done it, after measuring it all and getting it perfect, but I can't see why I would do it myself, at least right now, ... this is being my second speakers ever made. I don't want to make a mistake after all my hard work.

I am assuming these speakers will be accurate enough with the standard 'tweeter over woofer lined up vertically, with a good space top and bottom alignment that seems to be what everyone else does... I would like to try the offset woofer, but I don't trust myself and my skill enough to do it right now.