The series notch filter is used for eliminating/reducing impedance peak at resonant frequency of any drivers. However, since the frequency response curve of most drivers provided by manufacturers still can be roll-off smoothly at the low frequency side, why do we need to eliminate that impedance peak due to resonance? Please help recall my memory.
Also, most of modern speakers tend to have crossover points at lower frequencies compared to those loudspeakers in the 1980s. For instance, the modern 3-way speakers have 200Hz and 2kHz while the 80s speakers had 450Hz and 4.5kHz crossovers. However, I found some of those modern speakers haven’t had any (series) notch filter to handle the impedance peak at resonance anymore. So, does it mean some designers ignore that impedance spike? In all, is the imp. peak/resonance really matter?
Also, most of modern speakers tend to have crossover points at lower frequencies compared to those loudspeakers in the 1980s. For instance, the modern 3-way speakers have 200Hz and 2kHz while the 80s speakers had 450Hz and 4.5kHz crossovers. However, I found some of those modern speakers haven’t had any (series) notch filter to handle the impedance peak at resonance anymore. So, does it mean some designers ignore that impedance spike? In all, is the imp. peak/resonance really matter?
The high values of the woofer's passive low-pass filter react with the impedance peak, creating a bump in the frequency response by lowering the net impedance above the higher frequency impedance peak.
If you don't mind the dip in the impedance and the bump in the frequency response, then you don't need a series notch to eliminate the impedance peak.
You can EQ out the frequency response bump later if you want e.g. with DSP.
A series notch also lowers the impedance, just gives a flatter curve overall.
If you don't mind the dip in the impedance and the bump in the frequency response, then you don't need a series notch to eliminate the impedance peak.
You can EQ out the frequency response bump later if you want e.g. with DSP.
A series notch also lowers the impedance, just gives a flatter curve overall.
Impedance equalizers on dome tweeter resonances help the crossover to perform properly. Without them, the higher impedance at resonance can lead to more output in that region in some cases, reducing the effectiveness of the crossover.
Whether it's needed depends on the tweeter behavior, cross point, other crossover elements, etc. It's case specific.
Whether it's needed depends on the tweeter behavior, cross point, other crossover elements, etc. It's case specific.
In my first loudspeaker project I made a point of flattening the apparent impedance curve of each driver, as seen by the crossover network. In my subsequent projects, I discovered that usually this is not necessary. So, nowadays, I use resonant circuits only "as required". You have a range of tools in your toolkit. Use whatever is needed.
There isn't any 'hatred' just practical engineering. As has been noted, typically it's flattened out when necessary to ensure the filter slope tracks the target; without the components will interact with the changing impedance, altering the transfer functions, response, distortion & power handling.
Not all, but some yes. On average, MC tweeter design in particular has improved significantly since then.
It may not have one, be insufficient to cause an issue, or a simple resistive shunt may be sufficient to flatten it out. Some designers of course may ignore altogether for various reasons and accept any compromise entailed, but without full design details, that's up in the air.
Yes, but the extent varies from case to case.