1. when designing filters, how much should I worry about phase shift, is it that important eg can a 45deg shift be heard?
and if it is important how do you correct the phase in a passive filter?
2. when would you choose to use an active filter over a passive filter?
3. how do you choose between using a 1st order or 2nd order filter
4. What is the gain (I know it’s negative), of a 1st order and 2nd order passive filter?
thanks
and if it is important how do you correct the phase in a passive filter?
2. when would you choose to use an active filter over a passive filter?
3. how do you choose between using a 1st order or 2nd order filter
4. What is the gain (I know it’s negative), of a 1st order and 2nd order passive filter?
thanks
Phase shift is an integral part of a filter.
Your other questions depend on the application.
https://www.analog.com/en/resources/app-notes/an-649.html
Your other questions depend on the application.
https://www.analog.com/en/resources/app-notes/an-649.html
i am adding subwoofer driver to my speakers and I want to learn how to design a high pass filter for the full range driver I already have.
the filter will have cut off frequency around 150hz
i want to keep it simple if possible but without compromises
so from what I have read the first choice is passive or active, what are the pros and cons
and in this application should I use a simple 1st order filter or something else.
I am not experienced with filter design so I am maybe asking the wrong questions but I would appreciate some ’filter design for dummies’ type advice if possible to get me started in the right direction.
the filter will have cut off frequency around 150hz
i want to keep it simple if possible but without compromises
so from what I have read the first choice is passive or active, what are the pros and cons
and in this application should I use a simple 1st order filter or something else.
I am not experienced with filter design so I am maybe asking the wrong questions but I would appreciate some ’filter design for dummies’ type advice if possible to get me started in the right direction.
Only very simple 1st order analog cross-over filters sum to the original signal. Any analog 2nd order or more produce some kind of phase distortion, but it's not generally a big problem because speakers have much worse phase distortion due to resonances and physical displacement, so one more is hardly noticeable. Digital filters can do things that cannot be done with analog circuits because digital filters can use a delay to include both the past and future signals. One approach is to use a simple 1st order filter at the cross-over frequency and add more filters beyond the crossover frequency. But the best crossovers are custom designed to complement the drivers, not a tidy mathematical crossover.
Be careful what you wish for. This is just an elementary introduction.
https://www.calsci.com/audio/X-Overs.html
https://www.calsci.com/audio/X-Overs.html
Thanks both, I will study a bit more.
my initial thoughts are to use a passive CR filter but not sure wether 1st or 2nd order, I understand that the 2nd order will have a faster/sharper cut off but is this an advantage (i suppose this depends on the frequency curves of both drivers and the proposed cut off point).
my initial thoughts are to use a passive CR filter but not sure wether 1st or 2nd order, I understand that the 2nd order will have a faster/sharper cut off but is this an advantage (i suppose this depends on the frequency curves of both drivers and the proposed cut off point).
Second order is a more common choice. It may also give you simpler control than first, considering the impedance variations you'll encounter when crossing a sub, which may be a challenge.
I presume you'll be measuring to ensure the result, if you plan to do this by ear then I'd lean differently with my response. For example, there's no reason normally to require an active crossover, they tend to do the same thing when properly implemented.. however using one buffers the impedance resonance peaks out of the picture.
I'd ask whether you would want to cross to your subs. By overlapping them with your mains you have an opportunity to manage room modes.
I presume you'll be measuring to ensure the result, if you plan to do this by ear then I'd lean differently with my response. For example, there's no reason normally to require an active crossover, they tend to do the same thing when properly implemented.. however using one buffers the impedance resonance peaks out of the picture.
I'd ask whether you would want to cross to your subs. By overlapping them with your mains you have an opportunity to manage room modes.
Thanks for the reply.
to cut a long story short I have lowther dx4 full range drivers in BLH cabinets, not well matched and bass is missing, following a suggestion the intention is to modify them and add a woofer to each with 150hz high pass filter on lowthers. I suppose by relieving the lowthers of bass duties would be a good thin.
I don’t know much about impedance crossing between sub and main but if using active filter will remove this issue then active might be the way to go
to cut a long story short I have lowther dx4 full range drivers in BLH cabinets, not well matched and bass is missing, following a suggestion the intention is to modify them and add a woofer to each with 150hz high pass filter on lowthers. I suppose by relieving the lowthers of bass duties would be a good thin.
I don’t know much about impedance crossing between sub and main but if using active filter will remove this issue then active might be the way to go
Calling these a woofer rather than a subwoofer might help get the point across.. the definitions are a bit convoluted. In any case, what you want has been called a FAST, or a WAW. You ought to be asking that kind of question in the full range subforum. (let me know if you want to move the thread and name it appropriately)
