[Jmill]

I am considering ordering the kit and building a pair of 1801fs and I have a couple of questions.  Do most people glue a piece of hardwood lumber to another piece of mdf for the front baffle.  Since the wood will expand and contract at a different rate than the mdf, could this cause of problem.

2nd question regarding the port.  Has anyone tried having the port placed higher up on the back, closer to the midrange driver.  Any input would be much appreciated.

Thanks

[pem]

Dear Jeff,

I am considering ordering the kit and building a pair of 1801fs and I have a couple of questions.  Do most people glue a piece of hardwood lumber to another piece of mdf for the front baffle.  Since the wood will expand and contract at a different rate than the mdf, could this cause of problem.

I am not expert, but my feeling is that there is not risk:
 - the density are not so different
 - the length of the Ellis is not very important
 - even if the two piece of wood will expand at a different rate, this should be negligible. Please correct me if I am wrong.

2nd question regarding the port.  Has anyone tried having the port placed higher up on the back, closer to the midrange driver.  Any input would be much appreciated.

When I built my pair of Ellis, I put the port close to the tweeter (as indicated in Dave's guide). The bottom is occupied by the crossover, just under the binding posts.

  kind regards,
  Pemo

[Ron Stewart]

I am considering ordering the kit and building a pair of 1801fs and I have a couple of questions.  Do most people glue a piece of hardwood lumber to another piece of mdf for the front baffle.  Since the wood will expand and contract at a different rate than the mdf, could this cause of problem.

When I built my 1801f's, I used a double-thick MDF panel for front baffle, so I don't have personal experience with the MDF/wood combination. Dave does address it on his web site, though. In case you missed it when you looked at his site, here's a link.

http://www.ellisaudio.com/hardwood.htm

Ron

[David Ellis]

2nd question regarding the port. Has anyone tried having the port placed higher up on the back, closer to the midrange driver. Any input would be much appreciated.

Having the port at the base of the cabinet has 2 THEORETICAL advantages.

1.  It increases the distance between the port & midrange.  This will reduce the midrange front to back wave cancellations that occur significantly above the port tuning frequency.  The port will move midrange air too.  I believe this is VERY minor.

2.  The bass will couple with the floor when the port is closer to the floor.  I believe this is somewhat significant.

As mentioned elsewhere, I marginally prefer the bass from the 1801F.  I think it sounds smoother and more even.  I believe #2 above explains my preference.

Dave