Hello. I have two 4Ω mid range speakers I'd like to have as 8Ω. By adding 4Ω inductor (Z) in series, will this work? My crossover points on my 3-way speakers are 500Hz and 5KHz. I have designed and built simple 6dB / octave crossovers, designed for 8Ω speakers.
I am aware to add DC resistance to Z of said mid range speakers.
Hopefully DC resistance will be <1Ω.
Until I can afford 8Ω mids, I am experimenting.
I know working ƒ has b/w of 4.5 KHz.
Just got to sit down and calculate with abacus Ω(z) of appropriate inductor.
Any thoughts, objections or incite ? Thanks.
I am aware to add DC resistance to Z of said mid range speakers.
Hopefully DC resistance will be <1Ω.
Until I can afford 8Ω mids, I am experimenting.
I know working ƒ has b/w of 4.5 KHz.
Just got to sit down and calculate with abacus Ω(z) of appropriate inductor.
Any thoughts, objections or incite ? Thanks.
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Hi, the idea is to have lowpass and attenuation in one part, so to use a bobbin with very thin wire. The difference between a resistor and a coil is that the R has flat impedance in all LF range, the coil is frequency dependent.
A simple 1st order filter ( or so ... ?! not when counting the acoustical passband performance of the speaker ) obtained with C in circuit resonating at frequency well away midrange's Fs and the L having ohmage well >1 Ω, not under ; typical use in speakers where a woofer needs help in the midrange .
A simple 1st order filter ( or so ... ?! not when counting the acoustical passband performance of the speaker ) obtained with C in circuit resonating at frequency well away midrange's Fs and the L having ohmage well >1 Ω, not under ; typical use in speakers where a woofer needs help in the midrange .
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Short answer: no.
Slightly longer: no such thing as a 4 ohm inductor; they have a reactive impedance which continuously varies depending on frequency.
You *can* add a 4 ohm series resistor in series with each, but then you will be attenuating them by 6 dB .... are you sure you want that?
Thanks guys.
"- to make them suitable for 4 ohm, double C & half L"
Having double C is the issue. Well, I am trying to avoid that. Large capacitors that is. I guess going with 1/2 L is good thing (1/2 R).
So, I am forced to use electrolytics. NP of course. Might look at 16Ω mids in this design.
Best thing is, One can design passive xovers independent of one another (In regards to above and below of mid xover ƒ. Perfect for mids and bass drivers...
"you will be attenuating them by 6 dB"
I get it. No free meal ticket. ...Bugger.
Thanks Blokes. Thanks for the math free lesson of life!
... Furthermore I understand that capacitors and inductors (coils of metal) exhibit resistance to AC.
Glad I asked !
pps. Adding extra mid speakers (If I had them) of 4Ω in phase would double dB (3dB) less losses. And cost more money... Adding 4Ω pure resistive (to AC + DC) would add -6dB minus loss...
Worth a shot any way. I won't do it! I read that electros are rubbish (grainy etc -hysteresis and ESR) > 10KHz of ƒ.
"- to make them suitable for 4 ohm, double C & half L"
Having double C is the issue. Well, I am trying to avoid that. Large capacitors that is. I guess going with 1/2 L is good thing (1/2 R).
So, I am forced to use electrolytics. NP of course. Might look at 16Ω mids in this design.
Best thing is, One can design passive xovers independent of one another (In regards to above and below of mid xover ƒ. Perfect for mids and bass drivers...
"you will be attenuating them by 6 dB"
I get it. No free meal ticket. ...Bugger.
Thanks Blokes. Thanks for the math free lesson of life!
... Furthermore I understand that capacitors and inductors (coils of metal) exhibit resistance to AC.
Glad I asked !
pps. Adding extra mid speakers (If I had them) of 4Ω in phase would double dB (3dB) less losses. And cost more money... Adding 4Ω pure resistive (to AC + DC) would add -6dB minus loss...
Worth a shot any way. I won't do it! I read that electros are rubbish (grainy etc -hysteresis and ESR) > 10KHz of ƒ.
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Is this dual mid part of a 3way speaker?
Could you separate the Bass from the Mid/Treble and use two amplifiers?
An active low pass filter for the Bass driving amlifier.
An active high pass filter for the Mid/Treble driving amplifier.
Then use your passive Mid to Treble crossover.
Active is in my mind mate. Passive / vs Active. Please share your info with me Andrew. You have helped Me before...
I have not had privilege of listening to active speakers. If I was sat in front of said setup I'd comment, lavish. If I could play.
I am listening to my Leak stereo amp right now and accept change.
Point is (you say Andy) using active xovers is flexible... A bit like palette paint... Thanks.
I have not had privilege of listening to active speakers. If I was sat in front of said setup I'd comment, lavish. If I could play.
I am listening to my Leak stereo amp right now and accept change.
Point is (you say Andy) using active xovers is flexible... A bit like palette paint... Thanks.
active is very simple and very cheap to make changes compared to passive.
A Bass only speaker can manage with just a low pass filter in front of the Bass power amplifier. Just swap the resistors in the filter to change frequency. Fit the resistors into a DIL header and plug into a DIL socket.
If you keep a passive Mid to Treble crossover, then a simple high pass filter into this Mid/Treble amplifier could be all that is needed. Again the swappable resistor block makes for very easy changes.
A Bass only speaker can manage with just a low pass filter in front of the Bass power amplifier. Just swap the resistors in the filter to change frequency. Fit the resistors into a DIL header and plug into a DIL socket.
If you keep a passive Mid to Treble crossover, then a simple high pass filter into this Mid/Treble amplifier could be all that is needed. Again the swappable resistor block makes for very easy changes.
Do it properly as a complete simulation of the loudspeaker with all the drive units specified and then we will see more clearly what needs to be done.
Using 6db/octave crossovers for a 3way system is not going to work very well as the overlap of the drivers will be very wide.
Unless the drivers are very linear over at least 2 octaves where they overlap, each driver will impose the undesireable parts of its response upon its adjacent crossover partner. This may not make for the most desirable frequency response . In other words, the crossover rollovers are ' too shallow ', a 12db/octave crossover would work better for you I think, this would give you greater clarity across the midrange.
Loudspeaker design is quite complex in its simplicity, strangely enough.
C.M
Unless the drivers are very linear over at least 2 octaves where they overlap, each driver will impose the undesireable parts of its response upon its adjacent crossover partner. This may not make for the most desirable frequency response . In other words, the crossover rollovers are ' too shallow ', a 12db/octave crossover would work better for you I think, this would give you greater clarity across the midrange.
Loudspeaker design is quite complex in its simplicity, strangely enough.
C.M
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