Hello,
I have used the very good Closed-Box-WithDriverDb.xls of Electrical and mechanical limits
I have loaded the driver database with T&S parameters of the very good BEYMA 15P80FE (800W AES)
The SPL 1m at xmax = 7,5mm gives a wonderfull 91dB at 20 Hz in a 130L box with an amplifier 125W/4 ohm/12A.
Equalizer gain correction to get 91dB/20Hz needs a 51W VpIp/2.
At the end of the web page thor_splmax.htm , there is : « Equalizing the frequency response of a woofer with a "Linkwitz Transform" does not require any more power over what the driver can handle for maximum excursion without damage. Such equalization merely makes it easier to run the driver voice coil into its mechanical stops »
I agree of course, but what will protect the loudspeaker over the Xmax when I increase the PA volume ?
I we consider :
* my system is equalized to obtain 91dB/20Hz/Xmax=7,5mm on the woofer
* It has globally a sensibility of 100dB / 1W / 2,83V, it means my 3 ways loudspeakers delivers 100dB in all the frequency range if the volume of the amplifier is tuned in order to deliver 1W.
* But the woofer deliver a maximum of 91dB at 20Hz with a Xmax cone move of 7,5mm : for this frequency (20hz), a gain is added in the input signal (linkwitz transform or any other transfer function ) and the amplifier deliver 51W (but it is tuned with 1W)
so it’s ok...and marvelous on the paper
but what happened when i turn the volume button higher , ie in order the amplifier works at 100W (the PA is specified with 125W) ?
320 Hz : I will get 111dB at 320Hz and of course the cone is auto-protected because it is far from the Xmax
20Hz (and under 20 Hz): as the woofer deliver a maximum of 91dB at 20Hz with a Xmax cone move of 7,5mm with an input signal that need 51W, it means with 100W we will exceed the Xmax, it will give distorsion or dammage of the cone
So with an equalization that give a gain to reach Xmax, we need to protect the cone against Xmax over-excursion.
A simple solution is to set a high pass filter with an adapted cutoff frequency and also a well defined slope, but this is not a good solution because we want to follow Xmax (and not above) from 10hz to 20 Hz at any volume control.
I think the entire question is well treated here ; Using Limiters to Help Protect Loudspeakers
BUT, What is the solution, what is the device ?
1/ A frequency peak Limiter / compressor like this ?: FabFilter Pro-MB - Multiband Compressor
Can we implement it in the Hypex Filter Design (HFD) SW of the Hypex Fusion DSP, is it included in the HFD SW ?
I have used the very good Closed-Box-WithDriverDb.xls of Electrical and mechanical limits
I have loaded the driver database with T&S parameters of the very good BEYMA 15P80FE (800W AES)
The SPL 1m at xmax = 7,5mm gives a wonderfull 91dB at 20 Hz in a 130L box with an amplifier 125W/4 ohm/12A.
Equalizer gain correction to get 91dB/20Hz needs a 51W VpIp/2.
At the end of the web page thor_splmax.htm , there is : « Equalizing the frequency response of a woofer with a "Linkwitz Transform" does not require any more power over what the driver can handle for maximum excursion without damage. Such equalization merely makes it easier to run the driver voice coil into its mechanical stops »
I agree of course, but what will protect the loudspeaker over the Xmax when I increase the PA volume ?
I we consider :
* my system is equalized to obtain 91dB/20Hz/Xmax=7,5mm on the woofer
* It has globally a sensibility of 100dB / 1W / 2,83V, it means my 3 ways loudspeakers delivers 100dB in all the frequency range if the volume of the amplifier is tuned in order to deliver 1W.
* But the woofer deliver a maximum of 91dB at 20Hz with a Xmax cone move of 7,5mm : for this frequency (20hz), a gain is added in the input signal (linkwitz transform or any other transfer function ) and the amplifier deliver 51W (but it is tuned with 1W)
so it’s ok...and marvelous on the paper
but what happened when i turn the volume button higher , ie in order the amplifier works at 100W (the PA is specified with 125W) ?
320 Hz : I will get 111dB at 320Hz and of course the cone is auto-protected because it is far from the Xmax
20Hz (and under 20 Hz): as the woofer deliver a maximum of 91dB at 20Hz with a Xmax cone move of 7,5mm with an input signal that need 51W, it means with 100W we will exceed the Xmax, it will give distorsion or dammage of the cone
So with an equalization that give a gain to reach Xmax, we need to protect the cone against Xmax over-excursion.
A simple solution is to set a high pass filter with an adapted cutoff frequency and also a well defined slope, but this is not a good solution because we want to follow Xmax (and not above) from 10hz to 20 Hz at any volume control.
I think the entire question is well treated here ; Using Limiters to Help Protect Loudspeakers
BUT, What is the solution, what is the device ?
1/ A frequency peak Limiter / compressor like this ?: FabFilter Pro-MB - Multiband Compressor
Can we implement it in the Hypex Filter Design (HFD) SW of the Hypex Fusion DSP, is it included in the HFD SW ?
The Bag End subwoofers have a limiter that works by raising the cutoff frequency of a high-pass filter, if I remember correctly.
Way Down Deep II Bag End S21E | Sound & Vision
Way Down Deep II Bag End S21E | Sound & Vision
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