XO for Vifa PL18WO-08-09 and Vifa XT25TG30-04 MTM

[knightat83]

I am looking to build a pair of MTMs using the following drivers.


Vifa PL18WO-08-09
http://www.parts-express.com/pe/show...number=297-324

and

Vifa XT25TG30-04
http://www.parts-express.com/pe/show...number=264-555

In a sealed box. These are going to paired with a sub so low end extension is not that important. I have a set of DIY bookshelfs using the PL 17s woofers that I really enjoy so I am fairly set on using the PL 18s as my woofers but would be willing to consider a different tweeter if something better is available around the same price range.

I this woofer/tweeter combo would work well with a crossover of about 2000-2500 hertz from what i have read.

I am not skilled enough to write my own crossover network and was wondering if anyone knew of a project with a published XO design I could use or if someone could help me out with designing something custom for this task. In addition I am slightly worried about the impedance dipping much below 4 ohms as I am using a panasonic xr55 av receiver (yes I know this should be replaced soon).

I found this post:
MTM project using 7" vifa drivers

but i am not sure if this XO would work well with my woofers. Although it seems like it should.

Thanks in advance for any advice or help.

[Dr. Ram]

Originally posted by knightat83
In a sealed box. These are going to paired with a sub so low end extension is not that important.
would be willing to consider a different tweeter if something better is available around the same price range.
In addition I am slightly worried about the impedance dipping much below 4 ohms

knightat83,

- One element you should think about is the alignment of the sealed box. I suggest you go for a box alignment that provides greater damping such as a Bessel alignment because (i) you have a sub and (ii) if your amp output impedance /damping factor is an issue
- Try thinking about putting your woofers in series rather than in parallel. Many will cry foul at that suggestion but it's not as bad as it may sound. Then use a higher impedance tweeter with or without an L-pad, and your impedance issues will cease to be.

[andrew01]

There is a German website called ASE - Acoustic Systems Engineering - who have lots of DIY Vifa designs , some probably use those drivers - worth having a look...

[andrew01]

Forgot to add the URL

http://www.vifa.de/standbox.html

[sreten]

Hi,

http://www.speakerbuilder.net/web_fi...ct/erosmk2.htm

Is a possible place to start for a PL18 MTM. As stated in the linked
to post the XT25 is not the first choice tweeter for an MTM, Seas ?

/sreten.

[knightat83]

After further research I seem to have come to the conclusion that the "Natalie P." MTM (found at the link below) could be a good solution in my budget range.

http://www.htguide.com/forum/showthread.php4?t=13969

I have never heard any of the Dayton Reference Series line but every review I have seen to date gives them very high bang/buck ratings.

The crossover for this design is fairly simplistic compared to the Modula but seems to be a good starting point. At a later date I could possibly upgrade to the Modula crossover

The beauty here is that it seems like a good foundation for me to build from without being significantly over my head to start with.

Does anyone have strong opinions for or against this design? Right now my cabinets are sealed but I built 3 extra rear panels so I can still easily port them.

[andrew01]

Ohh I assumed you already *had* those vifa drivers.....