Given this graph, what kind of useful information can one get out of it?
Thanks!
Full Version: Frequency response / impedance graph
Hi,
Given this graph, what kind of useful information can one get out of it?
Thanks!
Given this graph, what kind of useful information can one get out of it?
Thanks!
oh and that's a midrange driver.. Focal 100 v slim
what do you want to know from it?
the 2 different lines represent the frequency response on different axis's
the lighter line would eb on-axis, the black line would be 30degrees off axis.
the graph tells you that the driver would be good for frequencies up to 2.5-3Khz, although you could push it to 4Khz without too much of an issue,
i expect it will have beaming/breakup issue around that point.
the large impedance spike (this will have been recorded in an IB setup) indicates that the driver has an FS of ~130Hz, so i wouldn't be keen to push it much below 200Hz.
my guess would be a 4-5 inch driver.
as for the spike at 2khz, it might be an issue, but wait until you get it in the car, as you'll find that the frequency response will change then anyway
the 2 different lines represent the frequency response on different axis's
the lighter line would eb on-axis, the black line would be 30degrees off axis.
the graph tells you that the driver would be good for frequencies up to 2.5-3Khz, although you could push it to 4Khz without too much of an issue,
i expect it will have beaming/breakup issue around that point.
the large impedance spike (this will have been recorded in an IB setup) indicates that the driver has an FS of ~130Hz, so i wouldn't be keen to push it much below 200Hz.
my guess would be a 4-5 inch driver.
as for the spike at 2khz, it might be an issue, but wait until you get it in the car, as you'll find that the frequency response will change then anyway
QUOTE (Mr_Bob)
i expect it will have beaming/breakup issue around that point.
as for the spike at 2khz, it might be an issue, but wait until you get it in the car, as you'll find that the frequency response will change then anyway
as for the spike at 2khz, it might be an issue, but wait until you get it in the car, as you'll find that the frequency response will change then anyway
Thanks for the reply
What's beaming/breakup issue?
Does the 2khz spike in the freq response mean it will be louder at that freq?
Thanks!
(copy and pasted)
Beaming:
Term used to describe a sonic characteristic in which high frequency sounds produced by an audio system tend to be too loud and harsh or grating with a distinct directional component.
Cone break-up:
Below a certain frequency, say 900hz, the cone vibrates as one piece, much in the same way a piston goes up and down in an engine. Above that 'piston band limit' frequency, the cone vibrates in sections. By the time a wave travels from the apex at the voice coil all the way out to the edge of the cone, a new wave has started at the voice coil. Think of a series of ocean waves. One comes in and crashes against a sea wall, the sea wall generates a new wave that starts back out into the ocean where it meets a wave coming in, they crash together, and for a moment it looks like a stationary wave going up and down, but not travelling. The same thing happens on the surface of the cone. The result is comb filtering and other anomalies that create the texture of the overall sound. Interestingly enough, this all takes place between around 1 and 4Khz, where our hearing is most sensitive. If you look at a speaker plot, you'll notice the response of the speaker is fairly smooth until it gets in this region.
Beaming:
Term used to describe a sonic characteristic in which high frequency sounds produced by an audio system tend to be too loud and harsh or grating with a distinct directional component.
Cone break-up:
Below a certain frequency, say 900hz, the cone vibrates as one piece, much in the same way a piston goes up and down in an engine. Above that 'piston band limit' frequency, the cone vibrates in sections. By the time a wave travels from the apex at the voice coil all the way out to the edge of the cone, a new wave has started at the voice coil. Think of a series of ocean waves. One comes in and crashes against a sea wall, the sea wall generates a new wave that starts back out into the ocean where it meets a wave coming in, they crash together, and for a moment it looks like a stationary wave going up and down, but not travelling. The same thing happens on the surface of the cone. The result is comb filtering and other anomalies that create the texture of the overall sound. Interestingly enough, this all takes place between around 1 and 4Khz, where our hearing is most sensitive. If you look at a speaker plot, you'll notice the response of the speaker is fairly smooth until it gets in this region.
The low frequency impedance peak shows you the Q and is related to the roll-off of the frequency response. The increase in impedance at the upper frequencies is due to the inherent inductance in the coil and besides the cone breakup etc, rolls off the upper frequency response.
There is no problem playing below 200hz, but obviously the frequency response rolls off below, as well as excursion issues at high power.
The 2khz peak will be noticeable, will contribute to the speakers "sound".
There is no problem playing below 200hz, but obviously the frequency response rolls off below, as well as excursion issues at high power.
The 2khz peak will be noticeable, will contribute to the speakers "sound".
How important is phase response to SQ?
In an anechoic environment, the phase will be directly related to the frequency response, ie flat frequency response = flat phase response.
In a car where there are reflections/resonances, the phase and frequency response becomes a bit more complicated...
In a car where there are reflections/resonances, the phase and frequency response becomes a bit more complicated...
In my honest opinion I never use frequency response graphs as any form of meaningful measurement, because as soon as you put that speaker in a car, using a crossover - the frequency response plot displayed no longer exists or has any relavance.
The impedance plot is useful for checking at which frequency and how low does the driver's impdeance dips, but again this can be altered once placed into a car or an enclosure.
Most plots like this are more or less useless.
The impedance plot is useful for checking at which frequency and how low does the driver's impdeance dips, but again this can be altered once placed into a car or an enclosure.
Most plots like this are more or less useless.
yeah i was just thinking that damon 
reading such a graph will tell you a lot about the workings of a driver and may assist you in driver placement, box design (if applicable) and xover design, but won't tell you much about the final sound in a car interior.
interesting to look at, tho, when you know to read the bastards
d
reading such a graph will tell you a lot about the workings of a driver and may assist you in driver placement, box design (if applicable) and xover design, but won't tell you much about the final sound in a car interior.
interesting to look at, tho, when you know to read the bastards
d
QUOTE (DJ-)
yeah i was just thinking that damon
reading such a graph will tell you a lot about the workings of a driver and may assist you in driver placement, box design (if applicable) and xover design, but won't tell you much about the final sound in a car interior.
interesting to look at, tho, when you know to read the bastards
d
reading such a graph will tell you a lot about the workings of a driver and may assist you in driver placement, box design (if applicable) and xover design, but won't tell you much about the final sound in a car interior.
interesting to look at, tho, when you know to read the bastards
d
Indeed, and I also believe that the graphs can aid you in selecting drivers for your purpose. If you come across a driver that has a relatively flat response on and off axis "anechoic-ally" then you can have a degree of confidence that the driver would perform with minimal adjustments.
Cheers,
Bon
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