Vifa PL18WO-09-04
Hi JC
I'm not familiar with 225/8 version
, but if it is the Vifa PL18 Premium Line model, I know it quite well 
. I designed 2 speakers with this woofer. You can view them at:
http://www.ampslab.com/sm62.htm
http://www.ampslab.com/tw62.htm
Regards
Hi JC
I'm not familiar with 225/8 version
, but if it is the Vifa PL18 Premium Line model, I know it quite well . I designed 2 speakers with this woofer. You can view them at:http://www.ampslab.com/sm62.htm
http://www.ampslab.com/tw62.htm
Regards
Hi JC
I'm glad to hear that the tw62 is what you are looking for. It is a nice speaker, more musical than the bookshelf version - sm62. It is also very practical. As it is, the tweeter height is just about right. You can easily increase the height by making the base plate thicker if you like.
About the caps, I think what you may be wondering is what are those across the 8u2, the 100p+100R and 10n+100R. Those are compensation networks. They improve the sound of the tweeter. The main tweeter capacitor is the 8u2 or 8.2uF. This you must have. Then there is the notch filter - 1mH+85uF+10R. This helps to reduce the resonance of the tweeter.
There is a picture of the internal bracing at: http://www.ampslab.com/step4_cutouts.htm
I kept the construction as simple as possible, so that it is easy for diy. The bracing is good enough, but for those with better tools and time they can of course improve on it.
The main problem with a design like this, slim and tall, is if you are not careful, the speaker will resonate at a few frequencies, like an echo. Follow my box dimensions and you will be OK.
Next important point is internal stuffing.
Fill up the space from the bottom to just below the tuning port with loose mineral fibre. This will absorb the main internal echo. Line the back and sides from port upwards to top of speaker with 1 inch thick fibres. That will help to reduce the mid-range back wave.
Regards
I'm glad to hear that the tw62 is what you are looking for. It is a nice speaker, more musical than the bookshelf version - sm62. It is also very practical. As it is, the tweeter height is just about right. You can easily increase the height by making the base plate thicker if you like.
About the caps, I think what you may be wondering is what are those across the 8u2, the 100p+100R and 10n+100R. Those are compensation networks. They improve the sound of the tweeter. The main tweeter capacitor is the 8u2 or 8.2uF. This you must have. Then there is the notch filter - 1mH+85uF+10R. This helps to reduce the resonance of the tweeter.
There is a picture of the internal bracing at: http://www.ampslab.com/step4_cutouts.htm
I kept the construction as simple as possible, so that it is easy for diy. The bracing is good enough, but for those with better tools and time they can of course improve on it.
The main problem with a design like this, slim and tall, is if you are not careful, the speaker will resonate at a few frequencies, like an echo. Follow my box dimensions and you will be OK.
Next important point is internal stuffing.
Fill up the space from the bottom to just below the tuning port with loose mineral fibre. This will absorb the main internal echo. Line the back and sides from port upwards to top of speaker with 1 inch thick fibres. That will help to reduce the mid-range back wave.
Regards
Thanks Eric, now I know why I couldn't find a PL18 225/8 in my Vifa catalog.
100p is not 0.1uF
10p is not 0.01uF
In capacitors, you will be working in uF, nF and pF. You will not work in F as F=Farad is a very large value.
uF means micro farad. This is equal to 1 Farad x 10^-6. Numerically, 1uF=0.000001 F (note-6 decimal places).
nF means nano farad. This is 1 Farad x 10^-9.
So, 1nF=0.000000001 F (note-9 decimal places).
Now comes the smallest, the pF.
pF means pico farad. This is equal to 1 Farad x 10^-12.
Therefore, 1pF=0.000000000001 (note-12 decimal places).
I think you can see why engineers use uF, nF,pF. It is so much easier than writing all those zeros.
Now comes the confusing part.
100pF is the same as 0.1nF. When you convert nF to pF, you multiply by 1000.
In other words, 1nF=1000pF
and 1uF=1000n.
Hence, 0.1uF=100nF
and 0.022uF=22nF
and 0.001uF=1nF=1000pF
Just think in multiples of a thousand.
Regards
100p is not 0.1uF
10p is not 0.01uF
In capacitors, you will be working in uF, nF and pF. You will not work in F as F=Farad is a very large value.
uF means micro farad. This is equal to 1 Farad x 10^-6. Numerically, 1uF=0.000001 F (note-6 decimal places).
nF means nano farad. This is 1 Farad x 10^-9.
So, 1nF=0.000000001 F (note-9 decimal places).
Now comes the smallest, the pF.
pF means pico farad. This is equal to 1 Farad x 10^-12.
Therefore, 1pF=0.000000000001 (note-12 decimal places).
I think you can see why engineers use uF, nF,pF. It is so much easier than writing all those zeros.
Now comes the confusing part.
100pF is the same as 0.1nF. When you convert nF to pF, you multiply by 1000.
In other words, 1nF=1000pF
and 1uF=1000n.
Hence, 0.1uF=100nF
and 0.022uF=22nF
and 0.001uF=1nF=1000pF
Just think in multiples of a thousand.
Regards
tw62
Hi JC,
Yes, the drivers in the tw62 are not flush mounted. It may improve the sound, just like rounded corners, but to me these are all secondary.
In speaker construction, the main points are:
1) A solid, air tight box. This will produce clearer bass. Panel flexing and bad dimensioning will muddle the bass.
2) Minimize internal mid-range. If too much is reflected through the cone or the port, it will distort the mids.
3) Use a good tweeter. This is the most important. 80-90% of the work in the crossover is on the tweeter.
Regards
Hi JC,
Yes, the drivers in the tw62 are not flush mounted. It may improve the sound, just like rounded corners, but to me these are all secondary.
In speaker construction, the main points are:
1) A solid, air tight box. This will produce clearer bass. Panel flexing and bad dimensioning will muddle the bass.
2) Minimize internal mid-range. If too much is reflected through the cone or the port, it will distort the mids.
3) Use a good tweeter. This is the most important. 80-90% of the work in the crossover is on the tweeter.
Regards
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.