AudioFreak said:
No. It is more likely that you are using Internet Exploder on a Windoz PC. bmp is supported there. BMP is not an internet standard graphics format, and for those who like a more svelt browser, use a mac or a unix box, bmps will most often not display -- it isn't a problem with their ISP or their computer it is the posting of a non-standard format graphic.
If i was to attach a tif file, an eps, or a photoshop file then most people would have the same problem.
dave
Internet Explorer probably can view BMPs in-line, but that is simply not the issue. The BMPs are getting attached as files (they are not being recognized as the standard GIF or JPG) instead of images, so they are not displayed in-line.
And Netscape hasn't been "svelte" since 3.x. Now if we all ran Lynx, we certainly wouldn't be having this problem...
PS BMPs are pretty much a standard format. You'd be hard pressed to find an image viewer/editor that didn't support it. It is just that the only officially supported web graphic formats are GIF, JPG and now PNG.
PPS anyone have anything ON topic to add?
And Netscape hasn't been "svelte" since 3.x. Now if we all ran Lynx, we certainly wouldn't be having this problem...
PS BMPs are pretty much a standard format. You'd be hard pressed to find an image viewer/editor that didn't support it. It is just that the only officially supported web graphic formats are GIF, JPG and now PNG.
PPS anyone have anything ON topic to add?
Please don't forget this thread...
Hi to everyone!
Just 30 minutes ago that I've been registered. I was wondering why you stopped answering to this thread by Grey.
I'm going to rebuild this active Linkwitz Riley XO by Elliott Sound Products. But although there's this tuning formula, I have difficulties in getting my XO frequencies of 80Hz and 2kHz.
For that reason, it was very interesting in reading to your replies!!
Hoping that my English isn't too bad for this forum!
Greetings from Cologne,
Chris
Hi to everyone!
Just 30 minutes ago that I've been registered. I was wondering why you stopped answering to this thread by Grey.
I'm going to rebuild this active Linkwitz Riley XO by Elliott Sound Products. But although there's this tuning formula, I have difficulties in getting my XO frequencies of 80Hz and 2kHz.
For that reason, it was very interesting in reading to your replies!!
Hoping that my English isn't too bad for this forum!
Greetings from Cologne,
Chris
Actually, I haven't forgotten...it's just that the computer virus that came to visit a while back ate a lot of my files--among them, my schematics--and I've had to slowly (read: nearly glacially) rebuild things. Once I got the virus eradicated, I ran into the inevitable problems that stem from Bill Gates and his paranoia that someone might wish to run non-Microsoft code under his operating system. (It's enough to make me wish that the religious folks were right, just so there could be a special corner of hell reserved for him...) Couple that with the fact that I needed to get some stories out so that I could make some money, and I've been slow adding stuff here and to the other threads (Mini-A, SOZ w/current sources, and...the Aleph-X project). Got three stories in the pipeline and another went out the door last week, so now perhaps I can get a bit of electronics in.
If I can scrounge some time, I'll drop in an entry here in the near future--possibly this weekend.
Grey
If I can scrounge some time, I'll drop in an entry here in the near future--possibly this weekend.
Grey
i believe grey has said previously in one of the threads that he works around mainframes all day and he doesn't particularly wanna learn another computer language and given that i've been doing Windoze and internet programming for a number of years now, i offered to make a site for him free of charge.... he said he'd get back to me and given his problems of late, i cant blame him for not doing so.
So a site might be in the works.
ps. Grey if your listening and still interested, the offer still stands, if u've lost my email addy, just reply here and i'll get back to you.
So a site might be in the works.
ps. Grey if your listening and still interested, the offer still stands, if u've lost my email addy, just reply here and i'll get back to you.
Hi Grey,
I know this thread is going on almost 4 years old, but it's a goodie!
You mentioned that the output needs a de-coupling cap. Is this like the Zen amp situation? Is 10,000 mF too much for this xover?
Also, do the capacitor values have to be converted into farads when inserted into the equations?
This xover will be used with a Zen on the top end and and mini-A on the bottom.
Thanks!
Vince
PS, I started to work on the MOX, but if I can get good results with a simpler XO, well that's what it's all about for me. I was even looking at passive line level. But your XO will help match the input impedence better, I think.
V
I know this thread is going on almost 4 years old, but it's a goodie!
You mentioned that the output needs a de-coupling cap. Is this like the Zen amp situation? Is 10,000 mF too much for this xover?
Also, do the capacitor values have to be converted into farads when inserted into the equations?
This xover will be used with a Zen on the top end and and mini-A on the bottom.
Thanks!
Vince
PS, I started to work on the MOX, but if I can get good results with a simpler XO, well that's what it's all about for me. I was even looking at passive line level. But your XO will help match the input impedence better, I think.
V
Folks, be aware that the PC I'm on is dying...seems like the bearings in the hard drive are going. In consequence, I may be offline for a day or three.
In the meantime...
Vince,
It sounds as though others are already answering your initial question, but I'll chime in. Since the DC blocking cap is working against the input impedance of an amplifier instead of a speaker's (quite low) impedance, it can be much, much smaller. For instance, a 3.3uF cap will get you down to 4.8Hz assuming a 10k input impedance. This is the sort of territory where you can begin thinking in terms of decent quality film caps instead of electrolytics. Yes, they cost more, but they sound better.
As fate would have it, my current thinking on crossovers is back more along the lines of the ideas outlined in this thread. Very simple does it.
What's this thread doing in Misc? I'm not infallible, but I thought I put it in Solid State.
Grey
In the meantime...
Vince,
It sounds as though others are already answering your initial question, but I'll chime in. Since the DC blocking cap is working against the input impedance of an amplifier instead of a speaker's (quite low) impedance, it can be much, much smaller. For instance, a 3.3uF cap will get you down to 4.8Hz assuming a 10k input impedance. This is the sort of territory where you can begin thinking in terms of decent quality film caps instead of electrolytics. Yes, they cost more, but they sound better.
As fate would have it, my current thinking on crossovers is back more along the lines of the ideas outlined in this thread. Very simple does it.
What's this thread doing in Misc? I'm not infallible, but I thought I put it in Solid State.
Grey
One more question!
Sorry Guys, but I still have a question about the equation.
In Grey's equation, c1=c2 and 1000pF to 10,000pF is ok to use. But when inserting the cap value into the equation, can I use it as pF or does the valus need to be converted to Farads for the formula to work correctly?
Thanks for all you help so far!
Vince
Sorry Guys, but I still have a question about the equation.
In Grey's equation, c1=c2 and 1000pF to 10,000pF is ok to use. But when inserting the cap value into the equation, can I use it as pF or does the valus need to be converted to Farads for the formula to work correctly?
Thanks for all you help so far!
Vince
Hi,
Can someone check my math to see if I'm doing these equations correctly?
Thanks,
Vince
__________________________________________
2500hz crossover point using Butterworth filter:
High pass
C1 & C2 are 1000pF
.7071/(2*PI*2500*1000)= 22.2 meg ohm
1.414/(2*PI*F*C)= 15.7 meg ohm
Low pass
R1 & R2 are 100 ohm
1.414/(2*PI*2500*100)= 1.11 mF (converted from pF)
0.7071/(2*PI*2500*100)= 2.22 mF (converted from pF)
Can someone check my math to see if I'm doing these equations correctly?
Thanks,
Vince
__________________________________________
2500hz crossover point using Butterworth filter:
High pass
C1 & C2 are 1000pF
.7071/(2*PI*2500*1000)= 22.2 meg ohm
1.414/(2*PI*F*C)= 15.7 meg ohm
Low pass
R1 & R2 are 100 ohm
1.414/(2*PI*2500*100)= 1.11 mF (converted from pF)
0.7071/(2*PI*2500*100)= 2.22 mF (converted from pF)
Hi Andrew,
I'm not really sure. I'm following along with what Grey wrote in the first post. If it helps, I like a flat reponse. Does unity gain mean there is no increase in output from the filter itself? 1 volt in 1 volt out?
mF is microsfarads in my equation. Probaby should have used uF.
thanks,
Vince
I'm not really sure. I'm following along with what Grey wrote in the first post. If it helps, I like a flat reponse. Does unity gain mean there is no increase in output from the filter itself? 1 volt in 1 volt out?
mF is microsfarads in my equation. Probaby should have used uF.
thanks,
Vince
Hi Vdi,
that one!
I think that is a unity gain S&K topology.
It is usual to set the resistors to get reasonable noise performance combined with usable capacitor values.
This is often achieved at audio frequencies by basing calculations on resistor values near 10k.
Using the version of the formula that fixes both frequency and resistor to get first guess on a cap value you can use.
C=root2/[Pi*F*R]=1.4142/3.1416/2500/10,000=0.000000018F=18nF
18nF is a standard value so the first guess is acceptable if you can source 18nF and match them yourself. If you can only get 10nF then second guess becomes 20nF using 10n//10n. However the other cap you need for the low pass is half this value C2=9nF, this is not a standard value. So you must use 10nF and 20nF or select some other available cap near this value.
Now the formula is re-arranged to R=root2/[Pi*F*C] to find the resistor (or resistor combination) that allows the use of 10nF and 20nF.
You will use the same values of resistors and capacitors in both the low pass and high pass versions of the filter. Just don't get the doubled values mixed up. I hate unity gain for just this reason, combined with the extra caps you need and it's bad numbers if Q is not =1/root2.
Equal value S&K costs an extra pair of resistors but is much easier to calculate and alter/adjust/experiment with.
Look up opamp unity gain Butterworth filter to see what it is that this discrete circuit is trying to achieve. There is another thread running just now that shows exactly that! Widen your horizons until your knowledge matches your needs.
BTW. your fingers hit the wrong keys on your calculator in post36.
Are you any good with spreadsheets? I have one from the Forum that does what you need.
that one!
I think that is a unity gain S&K topology.
It is usual to set the resistors to get reasonable noise performance combined with usable capacitor values.
This is often achieved at audio frequencies by basing calculations on resistor values near 10k.
Using the version of the formula that fixes both frequency and resistor to get first guess on a cap value you can use.
C=root2/[Pi*F*R]=1.4142/3.1416/2500/10,000=0.000000018F=18nF
18nF is a standard value so the first guess is acceptable if you can source 18nF and match them yourself. If you can only get 10nF then second guess becomes 20nF using 10n//10n. However the other cap you need for the low pass is half this value C2=9nF, this is not a standard value. So you must use 10nF and 20nF or select some other available cap near this value.
Now the formula is re-arranged to R=root2/[Pi*F*C] to find the resistor (or resistor combination) that allows the use of 10nF and 20nF.
You will use the same values of resistors and capacitors in both the low pass and high pass versions of the filter. Just don't get the doubled values mixed up. I hate unity gain for just this reason, combined with the extra caps you need and it's bad numbers if Q is not =1/root2.
Equal value S&K costs an extra pair of resistors but is much easier to calculate and alter/adjust/experiment with.
Look up opamp unity gain Butterworth filter to see what it is that this discrete circuit is trying to achieve. There is another thread running just now that shows exactly that! Widen your horizons until your knowledge matches your needs.
BTW. your fingers hit the wrong keys on your calculator in post36.
Are you any good with spreadsheets? I have one from the Forum that does what you need.
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