Vifa P21WO-39-08

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Has anyone heard this woofer in a 2-way speaker?
How does it perform in the upper frequency?
I'm a little bit scared by the peaks and dips that it has between
200hz-3000hz!
There's a big 2,5/3db peak around 1000hz!
Should I worry so much?
Do you think it would be possible to cross it higher than 1,8K?

WinISD shows a nice response in a 50Liters enclosure tuned at 26Hz for the best transient response possible at this volume!
It has -1db at 40hz, -3db at 33hz, -12db at 20hz!
The group delay is also nice: 14,2ms@30hz 8,7ms@40hz 5,6ms@50hz!

Are there better woofers than this one in the same price range?

Thanks!
 
Not the poly cone, but the same size treated paper cone from Vifa is in this design:

http://murphyblaster.com/content.php?f=New_Vifa_Tower.html

I have just finished gluing up the cabinets on this design and dropped the drivers in to see how it sounds. I am actually quite impressed. The mid range is not quite as detailed as my Lynn Olson Ariels, but then again the design cost less than half as much. The bass extension, however, is actually a little better.

Hope this helps,

Chris
 
loudspeaker evaluation

Here is a good evaluation that includes this driver. Scroll down to summary and conclusions if you want to skip all the test results. You'll see that the peerless driver one ups the vifa. The p21 seems to be a well respected driver and I've heard it in some really pricey Dunlavys but I believe it has been around for a while and for the money you can do better.

If your making a two way I think you will probably find designs out there with better combinations and in some cases lower prices. Try www.murphyblaster.com. The mbow and its lower cost variations would probably be awesome and you can always build the three way if you want more bass. Also search modula MT, Bob Brines tl with peerless, or look on this site for the diyaudio reference project. Lots more but those are the ones that came to mind.

I like the MBOW and the Modula mt or mtm. Tough to beat those dayton rs drivers as long as you use them right.
 
I've heard the P21 in a 2-way kit many (20!) years ago.
It's a very good, but older generation polycone and as such is a little too soft and polite from the bass to the midrange. You lose a little detail and transparency in the mids, but it still sounds good in a polite kind of way. Generally I like polycones but I wouldn't use anything bigger than 5" in the midrange.
I think there are better poly/paper or nextel drivers to choose from.
If you really want poly check out the Dynaudios on Ebay.
 
First I want to thank you for your responses!

kifeinthesink, you said that I could find something better for the money!
Since I want to build a 2-way floorstander crossed as low as possible (1.2k-1.5k), I'm searching for a good 8", and I want to find the best
for the money!

!!!!Any opinions for something better?!!!!(I really need opinions)


The P21 that is tested on the linkwitz site is an old one P21WO-20-08
and I don't think it coresponds with the P21WO-39-08!

David Gatti, I bet you heard the P21WO-20-08!
I don't want to use a polycone, but this is the best 8" speaker that I could find for my project, until now!
on ebay I couldn't find many dynaudio speakers:
http://search.ebay.com/dynaudio_W0QQfromZR40

Here's the project that I want to build:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=690

I really need your support to find a good 8", and a tweeter for it!
 
My mistake. I didn't notice the different numbers.

Have you looked at the Dayton rs drivers?

If you dont mind going with a 7 inch driver the rs180 is tough to beat for the money and the seas 27tdfc seems to be one of the best choices for a xo as low as your looking for. Look at the modula mt if you haven't already. Its pretty much what your decribing.

Look here for some more excellent driver tests.
 
Thanks for your replies David Gatti and kifeinthesink!
David, I checked those Peerless drivers, but they don't compare with the Vifa in terms of FR in a 50L BR box. The 830884 is better, but it is still under the Vifa(I don't like polycones, but this driver has some good graphs)!
Maybe the sound is better! Have you heard it?

I don't have money for that SS, I can afford maximum 80$ for the
woofer(I'll have to pay 40-50% more for taxes and transport)
and even so I would preffer an 8" due to grater bass!

kifeinthesink, I'm now checking that Dayton RS, it has a good price but does it have what it takes to beat a 60-80$ 8" woofer?

I would like to use an 8", crossed as low as possible 1,2-1,5khz
with a tweeter+waveguide!

Any other opinions for an 8" woofer to beat this Vifa:
WinISD shows a nice response in a 50Liters enclosure tuned at 26Hz for the best transient response possible at this volume!
It has -1db at 40hz, -3db at 33hz, -12db at 20hz!
The group delay is also nice: 14,2ms@30hz 8,7ms@40hz 5,6ms@50hz!
???
 
Alexnick, i believe you already asked this question, and somebody may have told you, but this woofer is very good :

Monacor SPH-200KE

very deep bass extension and good response, perfect for two ways.

there are options with more extended response but not combined with this kind of bass extension.
I think you should not be seeking the "best" bass extension, especially for a two way, more bass means more cone displacement, means more IM distortion in the midrange.

ALCONE AC8HE

this one is more efficient, can be used in a two way (a kit exists i believe), bass down "only" to 35 hz -6db, 44hz -3db . I believe that it's way enough for a two way with a 8" ,and that you shouldn't be seeking for the most bass extension if you are after sound quality, especially if you listen a bit loud

i would take the alcone over the monacor for a two way. The nomex mentionned are also a very good option
around 50 euros there is also the BEYMA 8BR40 that is very good, and it's a paper driver so it may be easier to cross over than the others listed

Don't look after 5hz lower at -3db, at the end the thing that is the more important to me is the amount of air a driver can displace without distorting to much and there are two parameters for this : SD and Xmax


my 2 cents
 
"I'm now checking that Dayton RS, it has a good price but does it have what it takes to beat a 60-80$ 8" woofer?"


here is a quote from the test site I provided a link to regarding the rs180. This is the 7" but I dont think you would be able to use the 8" rs in a 2way. Keep in mind the w18 is about $150 and the the rs180 is around $40.

"The RS180 is without a doubt the best value. It does not have any significant defects, except its FR curve gets funky above 1200 hz (or, it's linear distortion rises notably at 1600 and 2000). It can't quite match the smoothness of the FR curve of the W18, but has overall better distortion numbers when considering performance below 100 hz. In a two way, I would go so far as to say that the RS180 is better than the W18. "

As I said before you should really look at the modula mt and mtm if these drivers interest you. There are other MTM implementations using this driver but the modula mt is the only 2way I've seen.
 
W20RC3808 20cm 38mm Wool Cone 91 100 8 7.3 .92 18 31 83 1.3 .28 .23 ±5.0 183
----------+----+----+---------+--+---+-+---+---+---+----+---+---+---+---+----+-----+

this is a driver soounds surprisingly good and cost very little ;)
It's a silver flute go to solen and you will see it there.www.solen.ca
 

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Nemophyle, that Monacor speaker has the best extension I have ever seen
on the 8" range(50L), but the Group delay is also huge!
This makes me wonder how good would the transient response be?

The Alcone has less extension, indeed, but it looks very well designed and it is very efficient, so no attenuation for the tweeter(this means better dynamics)!

When does IM become a problem? I mean at what frequency/excursion?
If I would have a low crossover point of 1,2-1,5k, how much would a
12mm(p-t-p) excursion distort the midrange?


kifeinthesink, I have checked the Dayton RS180.In a 25L enclosure tuned at 40hz(to achieve the best transient response possible) it has more extension than the ALCONE AC8HE in a 50L tuned at 35hz, pretty impressive!
The downside is that it lacks low-end extension!

I'll think about these drivers, but I want to achieve good extension, and sound quality at the same time!

newfinish, I'm checking that Silver Flute now!
Do you know a good program that simulates Transient Response?
 
hello alexnick

i think in the end your choice will be a tradeoff.

here is the way I would take it :

you can't obtain same kind of bass with a 8" that you can with a 12"
and with room gain, a 40hz -3db theoretical point is more than reasonable and will give you great satisfaction

so here are the solutions I would consider :

- Do a two way with a 8" that is not going to run out of linear excursion at 20w like the SPH-200KE. my choice would be the alcone AC8HE. I designed a two way with this one for a friend and it is really good. the tradeoff is, you lose a little extension but you gain in power handling, so you gain in transparency and distortion at medium to high listening volumes
-Do a 2.5 ways with two SPH-200KE : you have the low end and power handling.
-Do a more traditionnal 3 ways ( but i think its out of the question) with big bass driver
-Do a 2 way with a bigger driver and bigger waveguide. The benefits when compared to your solution are :
- a 10" or 12" waveguide will give more gain to the tweet , so you can cross lower.
- the woofer will move less for a same spl and bass extension, and so it will distort less


the first solution is the easier and it is the one i recomend you if you are on your first project.
the second solution would be a good tradeoff i think, two SPH200KE would give you 104 db at 30hz with 60w of power.
the last solution corresponds to the project i have actually. it is gonna be a little more difficult.

also i asked myself, how are you gonna deal with the waveguide ?
 
Nemophyle, indeed I have to make a compromise, but I really want to have some extension, and it would be possible because the speakers will
be sitting close to my listening seat ~1,5m so no need for big power handling!

My budget is quite small, so I can't afford a 3-way at the moment,
but a two way would be perfect!
The waveguide can't be larger than 8", because I want a narrow baffle!
I think I'm going to make a custom waveguide made from wood, I don't know for sure!

When does IM become a problem? I mean at what frequency vs. excursion?

Have you decided what are you going to build?

I made some graphs with the tweeter response and even If I add an waveguide and a Cauer filter set to 1,2k the tweeter would still have
to move more than if I was to cross it at 2khz with a 12db/octave!
This is quite bad, because it needs to play with 4db->0db more in the
1,2khz->1,7khz region!
 
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