Dimensions and driver placement

[Tai-Pan]

Hi,


I am looking into building some new rears using the Georgia Tech design. The reason I am doing this is I miscalculated on the construction of my home theater and now the door will hit my current rears. (Yes, I am that stupid)

Thus, I need some REALLY thin speakers. Like maybe only an inch or two deeper than the driver.

It is my understanding that, assuming the bracing is good, changing the dimensions of the speaker should have no effect. Correct?

My question is; are there any driver positioning changes that I should consider? With a much larger face, is there any reason why they should be closer or further apart?

Thanks for your help!

 

[Ken L]

that's pretty thin

originally posted by Tai-Pan

" It is my understanding that, assuming the bracing is good, changing the dimensions of the speaker should have no effect. Correct? "

I'm not sure that is correct in this case - I believe that this statement is a generalization that may not be accurate if proportions are skewed past certain limits - I would think that internal wavelengths would play a big part in this

Do you have other potential solutions here?

Maybe above the door near the ceiling?? I usually keep the rears above seated head height anyhow - you don't have to worry about furniture and/or blaring right into someone's ear.

Plus, rears take a certain amount of playing around with positioning to get it right anyhow, depending on the room/system

That's a good looking speaker for the rears by the way.

I know someone else I'm going to send a link to on that design

Ken L

 

[planet10]

It is my understanding that, assuming the bracing is good, changing the dimensions of the speaker should have no effect. Correct?

You will change the internal resonant modes inside the box, but as long as you don't create any really long dimensions relative to the others you are OK. A long dimension compared to others can be used to advantage as in quarter-wave resonant designs (ie TLs, and voigt pipes)

My question is; are there any driver positioning changes that I should consider? With a much larger face, is there any reason why they should be closer or further apart?

Drivers should still be kept as close together as possible but differing placement on the baffle can have dramatically different effects on the diffraction characteristics,

You can download the Baffle Diffraction Simulator at FRD Consortium and play with driver placement.

dave

 

[Tai-Pan]

http://users.ece.gatech.edu/~mleach/labsp2/

Thats the two way version.


Anyway if I knocked of the depth by two inches (to 5.5 deep) and increased the corresponding values would that be to much?

Forgive me I am not exactly sure what reasonent modes are. Is there somewhere I can read up about them?


Thanks for all your help so far!!

 

[planet10]

Anyway if I knocked of the depth by two inches (to 5.5 deep) and increased the corresponding values would that be to much?

That isn't too big a change, should work fine.

Forgive me I am not exactly sure what reasonent modes are. Is there somewhere I can read up about them?

A waveform can be excited that stands across the parallel walls of the enclosure. This, if not damped can be heard thru the box or back thru the cone of the speaker. The damping you put in the box is used to kill these. Better yet is to make a box with non-parallel sides and make it much harder for them to develop.

dave

 

[struan]

Hey Tai-pan,
I just built a pair using that design this weekend! They need to be broken in (they're a bit dark right now), but I'll let you know how they sound after a few hours.

Wow, what a coincidence! You're thinking of making a pair of those, and I just did...that's a cosmic connection, man.