Floorstander w/ Vifa P13 & D27 based on Wiki?

nrgy

Member
2004-03-15 4:55 am
Redmond
I have a pair of Vifa P13 and D27 speakers lying around from a project I planned to undergo last year but never got around to it. I am interested in doing something with these again...and am looking at building some floorstanding speakers. First off, I planned to build the Wiki project using the single cap on the tweeter. I would still like to go this route as I am not comfortable with building complex crossovers, and I would rather concentrate my efforts on building the enclosure.

My question is, the Wiki was intended for a bookshelf enclosure...if I try to use this design in a much larger floorstanding enclosure, how will this affect the sound? Also, can I expand this idea into a MTM or TMM design using the D27 with the cap, and 2 P13s running fullrange?

Once again, many questions for a first timer. Thanks.
 
I have to agree with dave as a TL such as the TLb would be the best way to use those drivers in a floorstander as the design as is would not be suitable.

x. onasis who built and tested the different variations said he was amazed at bass in the TL version.

BTW, the Wiki has been updated with thoughts on a larger bookshelf box (no good) using the same number of drivers as well as some alternative series crossovers.

An option has been added in the Wiki of a vented box using a 0.5 woofer on the back for BSC which IMO is better way to use the second P13 than a MTM or TMM with all the drivers on the front. This could be adapted to a floorstander with the excess volume closed off. It still would not be as good as the TL IMO as it could not compete with the bass extension, but would still make a very nice speaker.

An MTM needs a more complex crossover to be successful and the TMM could be done with the bottom woofer used as a 0.5 and not fullrange.

Ah... build them all and let us know ;)

Cheers
 
I can't see there being a real issue using the second p13 as the .5 woofer in an MTM arrangement.
I use 2 p17's in an MTM configuration and using the bottom woofer as the .5 for a 2 and a half way seemed to work pretty well.
This might cut down on some possible lobing issues.

If you keep the crossovers outside the enclosures while you experiment it's worth the effort to try
Whatever you end up doing the p13 will need some sort of BSC even if you are using 2 per speaker because they can tend to get a little midrangy if not compensated for

Best of Luck
 
I tried the 0.5 woofer on the front in a TMM arrangement and on the back which was far better IMO and really helped the speaker perform. An elegant and efficient way to solve BSC as you only get back what you lose when done right and the SPL of the speaker benefits compared to doing it in the crossover where you reduce the speaker SPL to bring it in line with the BS. The benefit is you need less power to make them sing.

If the little D27 / P13 in the Wiki is used close to a wall, no BSC is required but be aware that it is light on the bottom end but majors in the mids and upper bass. Soon as you bring them into the room away from the wall, then BSC is a must. There's a great graph on the TLb pages that demonstates this by having the second woofer on the back as well as showing where the BS starts on the monopole. BTW, the complete article on the TLb is a worthwhile read.
http://homepage.mac.com/tlinespeakers/TLS/projects/tlB/images/Fig52L.gif

If the top end is too bright, then it can be brought down with an L-Pad or single series resistor which would need a different single cap value. The alternative series xo's suggested take care of that and can be tweaked.
 
rabbitz and Dave...
I don't doubt that the woofer on the back of the speaker is a more effective way of baffle step, I tied it myself and it worked well but it may not be solution for every situation.
Placement to the back wall now becomes more sensitive because of this and in my experiments , the woofer on the back provided me with pretty much all of the 6 db baffle step which was a little too much. You may require only a moderate amount of BSC in which going the .5 woofer on the front may provide a little more flexibility.
There are also dispersion advantages going MTM if the speaker is going to be used for both home theater and music so if this configuration is desired then you could do effective BSC if you needed to.
Just wanted to give him an option if in fact this style of speaker was desired thats all.
 
fazman said:
Placement to the back wall now becomes more sensitive because of this and in my experiments , the woofer on the back provided me with pretty much all of the 6 db baffle step which was a little too much. You may require only a moderate amount of BSC in which going the .5 woofer on the front may provide a little more flexibility.

In an x.5-way speaker the amount of BSC provided should be no different if the driver is on the front or the back. On the back thou, placement close to a wall can be more problematic.


There are also dispersion advantages going MTM if the speaker is going to be used for both home theater and music

A true MTM pushes the required XO lower than i like to think about. Many are more about marketing than anything else. I did the math last night -- 2 3" Auras, + a tweeter small enuff that if i offset the tweeter i could still get the M baskets to touch, and the interdriver distance suggested an XO less than 4 KHz. With the P13 and the D27 it will be alot lower than that -- lower than the tweeter can really go i bet.

dave
 
jleaman said:
Hope you don't want any Bass for this design..

You're half right (they do have some) and as I've said previously there is little bottom end in these and miss out on the lower octave but what they have is the great mid bass, upper bass and mids of the P13 which is one of the best value drivers around with a great sound. If one needs oomf boom oomf, then this is not the speaker of course. Put the P13 into a TL would fill the gap nicely.

The idea of this little speaker was to give the newbie something to build that had readily available drivers, cheap build price, easy crossover, sounded good and would be a building block for future projects or tweaking so they could learn. Using these they could build another set of speakers and if the upper bass, mids etc were as good or better than the P13/D27 they would know they are going in the right direction.

These started from this thread http://www.diyaudio.com/forums/showthread.php?s=&threadid=25590&highlight=
and I would have liked to use this better tonally balanced Peerless speaker that is shown in this thread http://www.diyaudio.com/forums/showthread.php?s=&threadid=54533&highlight=
but the tweeter is only available in Oz and the speaker in the Wiki had to have the drivers available everywhere.

They had to be a speaker that wouldn't go to waste after you did the initial building.... could have a sub added for the missing octave; used as speakers in a HT; pulled apart and drivers used in a 3-way or TL; computer speakers; replacement speakers for a mini system; and the list goes on.

Not meant to be the you beaut blow my socks off, but a starting point and give a new builder a taste of what good clean mids etc can mean to music. Getting bass is easy in a design with suitable drivers, but getting great mids is a lot harder.

This is just a little bit of back ground on what they were meant to achieve.

If you want to put up another design.... go for it as the Wiki is sitting there and under utilised.

One question... has anybody besides x. onasis (he started the initial thread and put his money and time where his mouth is) actually built this thing.