FX10 Distance from Cone to enclosure rear wall

[imk]

Hello,
I am building a Transmission Line enclosure for a FX10 drivers i have done all the design and there is a distance of approx 75mm from rear of cone to rear of enclosure inside wall. Is this enough space behind the speaker as i can't find any guidelines for cone to rear wall distance.
Many thanks imk

[chChrLam]

http://www.visaton.de/bilder/zeichnungen/gross/fx10_tz.gif

Are you asking if you have enough space for the magnet, so it fits in your design?
Or something else?

[imk]

http://www.visaton.de/bilder/zeichnu...ss/fx10_tz.gif

Are you asking if you have enough space for the magnet, so it fits in your design?
Or something else?

There is about 75mm, so enough for magnet. I was asking if cone is too close to rear wall for some audio technical reason.

[Frankynstone]

If the rear wall is very close to the cone, it virtually adds a bit of air load and changes the resonant frequency. You can simply mount the chassis in a board (baffle of your planned box) and hold it a) in the free air and b) against a wall. Measure the change of the resonant frequency by the shift of impedance maxium. There will be a change, no doubt. But hopefully not too dramatic to spoil your project.

Oh, and there's another aspect. It's the reflection of mid-range frequencies by the rear inside wall. You should glue a piece of felt or another sound absorbant material against it to avoid interferences.

[Frankynstone]

A friend told me that he builds very small chambers behind midrange chassis which is mechanically tricky, sometimes, but not bad for the acoustics.

You can also see very flat wall-mount speakers like Portrait Solo. If you compare the frequency responses of this speaker to that of the chassis B 80, you can see quite a bit of ripple in between 1kHz and 4kHz. This is caused by reflections on differend walls and edges.

Without getting too deep into detail, if you put enough damping material inside and chamfer the edges outside, it'll not be much of a problem.