Hi,
I'm using a program called LSPWLITE to model rreflex box properties for a JX92s.
The box properties involve a Q value which defaults to 15. There is no help text and I'm not sure what to enter here - can somebody explain in basic terms about this value
There are also other box alignment ratios that I'm not sure about.
Thanks.
I'm using a program called LSPWLITE to model rreflex box properties for a JX92s.
The box properties involve a Q value which defaults to 15. There is no help text and I'm not sure what to enter here - can somebody explain in basic terms about this value
There are also other box alignment ratios that I'm not sure about.
Thanks.
From Boxplot:
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Box Parameters:
Alpha: System Compliance ratio.
Alpha determines how big to make the box.
Alpha is the ratio of box volume (Vb) to speaker Vas.
Alpha = Vas / Vb
For a Bandpass enclosure, Alpha only determines the Rear chamber volume. The front chamber volume is determined by H parameter and the basic driver characteristics.
H: System tuning ratio.
H determines what frequency the system will be tuned to, and therefore how to design the vent.
H is the ratio of the speaker free air resonance to the system tuning frequency (Fsb).
H = Fs/Fsb
For Bandpass enclosures the H parameter is not a tuning ratio and does not directly correspond to the tuning frequency. This parameter actually is called the damping factor and determines the basic frequency response shape. In some texts this parameter is labeled S, but it is kept as H in Boxplot for consistency.
Ql or Q7: Q from box leakage losses.
This is a measure of how airtight a box is. Even vented boxes MUST be airtight (except for the vent hole of course).
This is the enclosure Q at Fb from leakage loss. (better sealed boxes have higher Q's) This parameter must be measured after the enclosure is built. Start with 7 as a good estimate. A Ql of 3 or less is unacceptable and must be improved, a Ql of 15 or higher is very good.
Ql is not considered for the Bandpass enclosure type
Fe/Fs:
This is the ratio of the Equalizer resonant frequency to the box frequency.
D
This is the equalizer Damping coefficient. D = 1/Q
<>
<>
Box Parameters:
Alpha: System Compliance ratio.
Alpha determines how big to make the box.
Alpha is the ratio of box volume (Vb) to speaker Vas.
Alpha = Vas / Vb
For a Bandpass enclosure, Alpha only determines the Rear chamber volume. The front chamber volume is determined by H parameter and the basic driver characteristics.
H: System tuning ratio.
H determines what frequency the system will be tuned to, and therefore how to design the vent.
H is the ratio of the speaker free air resonance to the system tuning frequency (Fsb).
H = Fs/Fsb
For Bandpass enclosures the H parameter is not a tuning ratio and does not directly correspond to the tuning frequency. This parameter actually is called the damping factor and determines the basic frequency response shape. In some texts this parameter is labeled S, but it is kept as H in Boxplot for consistency.
Ql or Q7: Q from box leakage losses.
This is a measure of how airtight a box is. Even vented boxes MUST be airtight (except for the vent hole of course).
This is the enclosure Q at Fb from leakage loss. (better sealed boxes have higher Q's) This parameter must be measured after the enclosure is built. Start with 7 as a good estimate. A Ql of 3 or less is unacceptable and must be improved, a Ql of 15 or higher is very good.
Ql is not considered for the Bandpass enclosure type
Fe/Fs:
This is the ratio of the Equalizer resonant frequency to the box frequency.
D
This is the equalizer Damping coefficient. D = 1/Q
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Hi,
Don't forget that driver leaks is embedded in the Ql value and no drivers are without and can be of significance.
b
Ql or Q7: Q from box leakage losses.
Don't forget that driver leaks is embedded in the Ql value and no drivers are without and can be of significance.
b
Thanks for the info - another related question:
The box designer programs (boxplot etc) will allow estimation of the ideal box size. If sufficient wadding is used to increase the virtual box size by 20% (obviously avoiding the port) will this extra value be included in the ideal box size (ie the ideal box is 20% smaller) or does it not effect the ideal size - so the optimal virtual volume is ideal + 20%?
The box designer programs (boxplot etc) will allow estimation of the ideal box size. If sufficient wadding is used to increase the virtual box size by 20% (obviously avoiding the port) will this extra value be included in the ideal box size (ie the ideal box is 20% smaller) or does it not effect the ideal size - so the optimal virtual volume is ideal + 20%?
Yes, as that's what the driver will effectively be seeing. This is assuming your program does not take account of stuffing. If you aren't sure if your program takes account of stuffing, just play like it has none and factor in the increased volume.
You are straying into muddy waters with this though, results will be varied and unpreductable.
You are straying into muddy waters with this though, results will be varied and unpreductable.
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