Hi,
I make passive crossover on focal utopia driver in car.cutting frequency at 3500 hz between woofer and tweeter.cutting frequency is fine and already flat between woofer and tweeter.but i see on RTA the response is peak at 1Khz and 1.25 Khz +6db!!,this is woofer frequency range.i don't know why this driver can peak,maybe this is about acoustic problem and phase problem since the speaker is location at car door factory location .off axis and face to face between left and right speaker.
Anyone know passive crossover schematic for reduce this peak?
i don't want to use active equalizer since that will add noise.
now i use 6 db with zobel for woofer and 12 db for tweeter.
please advice and any suggest for this.
I already replace the woofer with other brand like vifa M18WN,Eton but the peak is at the same location 1kHZ and 1.25 KHz,....the midrange voice very attack to my ear because this peak...please advice.
I make passive crossover on focal utopia driver in car.cutting frequency at 3500 hz between woofer and tweeter.cutting frequency is fine and already flat between woofer and tweeter.but i see on RTA the response is peak at 1Khz and 1.25 Khz +6db!!,this is woofer frequency range.i don't know why this driver can peak,maybe this is about acoustic problem and phase problem since the speaker is location at car door factory location .off axis and face to face between left and right speaker.
Anyone know passive crossover schematic for reduce this peak?
i don't want to use active equalizer since that will add noise.
now i use 6 db with zobel for woofer and 12 db for tweeter.
please advice and any suggest for this.
I already replace the woofer with other brand like vifa M18WN,Eton but the peak is at the same location 1kHZ and 1.25 KHz,....the midrange voice very attack to my ear because this peak...please advice.
This is very possible.
You may use what is called as a parallel notch filter. Now, I'm not exactly sure on its effects with phase and such, though I know that generally this can be applied to circuits for on-axis response. Here is a link to a calculator. Notch Calc .
Phase aside, the peak may be caused by early reflections as the woofer is in a car, car's are known for early reflections which usually allow people to bump the xo point between tweeter and crossover an extra 500Hz. or so. I don't like to do this personally, as breakup modes are breakup modes so, crossing over at a low point is good. Hope this helps. BTW, is it a problem with your SPL meter? Just for gazing purposes, can you post a picture of your response?
You may use what is called as a parallel notch filter. Now, I'm not exactly sure on its effects with phase and such, though I know that generally this can be applied to circuits for on-axis response. Here is a link to a calculator. Notch Calc .
Phase aside, the peak may be caused by early reflections as the woofer is in a car, car's are known for early reflections which usually allow people to bump the xo point between tweeter and crossover an extra 500Hz. or so. I don't like to do this personally, as breakup modes are breakup modes so, crossing over at a low point is good. Hope this helps. BTW, is it a problem with your SPL meter? Just for gazing purposes, can you post a picture of your response?
A parralel notch filter is straightforward but you will need
the Zobel network on the driver for the filter to work well.
In reality your very lucky if thats your only problem.
With a friends in car set up the main problem was a 12dB
dip in the same range, chucking boost at a big dip doesn't
work remotely as well as cutting back peaks.
sreten.
the Zobel network on the driver for the filter to work well.
In reality your very lucky if thats your only problem.
With a friends in car set up the main problem was a 12dB
dip in the same range, chucking boost at a big dip doesn't
work remotely as well as cutting back peaks.
sreten.So, that would be a parallel notch filter in addition with a zobel?
The zobel would be used to flatten the impedance increase as frequency increases, correct? A zobel calculator can be found here .
Anyway, I'm curious to find the position of the microphone (SPL meter) relative to the transducer being measured. Sreten, where was the mic located? How far? (as best as you can measure).
The zobel would be used to flatten the impedance increase as frequency increases, correct? A zobel calculator can be found here .
Anyway, I'm curious to find the position of the microphone (SPL meter) relative to the transducer being measured. Sreten, where was the mic located? How far? (as best as you can measure).
Thank you bose,my rta is audiocontrol,i think no problem with the microphone since that already calibrate at audiocontrol 1 month ago.and the peak 6db at 1.25Khz can hear by ears too.
i use the calculator for notch filter and found very big value for inductor.
I don't have digital camera so i can't post the response picture.
the response from 20 up to 900hz is normal just +/- 3 db and will up at 6 db from 1-1.25khz,than down again at 2.5khz and flat up to 16khz.so the problem only in 1-1.25kHz.
how about use the parametric equalizer??
i use the calculator for notch filter and found very big value for inductor.
I don't have digital camera so i can't post the response picture.
the response from 20 up to 900hz is normal just +/- 3 db and will up at 6 db from 1-1.25khz,than down again at 2.5khz and flat up to 16khz.so the problem only in 1-1.25kHz.
how about use the parametric equalizer??
Sma,
I guess that rules out any measurement equipment. Don't sneer at me for asking this though, as many people OFTEN forget about the calibration of their devices.
Parametric Equalizer? That'd work too! And, it would be smaller and a lot easier to test with as well. You may be already thinking about this, but boosting the response above and below your bump may not be the way to go as it would do gross things to power requirements and excursion. Detracting from however, is easier...Hope you figure out your bump problem.
I guess that rules out any measurement equipment. Don't sneer at me for asking this though, as many people OFTEN forget about the calibration of their devices.
Parametric Equalizer? That'd work too! And, it would be smaller and a lot easier to test with as well. You may be already thinking about this, but boosting the response above and below your bump may not be the way to go as it would do gross things to power requirements and excursion. Detracting from however, is easier...Hope you figure out your bump problem.
Hi everybody. I have the same problem!!!!!
I just bought a set of Utopia 165W for my car. I noticed by hearing and measuring them, both at home and in car, that they have a smooth yet large spl bump around the 1Khz. And its not just something shown in measurements, its audible too.
Its definetly a speaker problem since i dont get the same bump with other speakers i used, neither in the car on at home.
I made a notch filter ( parallel RLC 10Ù, 0.8mÇ, 32ìF) in series with the signal, and the bump disappeared, giving me a very flat response. But the IMPEDANCE AND PHASE curves got like a heartbeat diagram, so i removed the notch for the obvious reasons.
WTF?? So expensive and well reputated speakers, are they supposed to be like this?? Anybody has experience on this?
Thanks for any reply.
I just bought a set of Utopia 165W for my car. I noticed by hearing and measuring them, both at home and in car, that they have a smooth yet large spl bump around the 1Khz. And its not just something shown in measurements, its audible too.
Its definetly a speaker problem since i dont get the same bump with other speakers i used, neither in the car on at home.
I made a notch filter ( parallel RLC 10Ù, 0.8mÇ, 32ìF) in series with the signal, and the bump disappeared, giving me a very flat response. But the IMPEDANCE AND PHASE curves got like a heartbeat diagram, so i removed the notch for the obvious reasons.
WTF?? So expensive and well reputated speakers, are they supposed to be like this?? Anybody has experience on this?
Thanks for any reply.
I have a good friend that owns a car stereo shop and I know from him the utopia mids, especially the 6.5's, have some peaky response. It is inherrent in the design, focal's crossovers compensate for the artifacts but they are fairly difficult to tame diy. The old Xpert series did not have this problem.
My advice is to contact Focal directly. Any time I have talked to anyone there they have been very nice, never patronizing. For instance I had a set of TN-51 tweeters and I lost the flush mount cups while moving. i called them up and told them exactly what happened and they overnighted a full mounting set to me with flush mount, angle mount, and new grills. Great service.
My advice is to contact Focal directly. Any time I have talked to anyone there they have been very nice, never patronizing. For instance I had a set of TN-51 tweeters and I lost the flush mount cups while moving. i called them up and told them exactly what happened and they overnighted a full mounting set to me with flush mount, angle mount, and new grills. Great service.
punchpeanut said:
Focal's crossover (which is what i am using) has nothing to compensate with the spl bump, its a typical 4th order low pass and a typical 4rth order high pass, with two switches and resistor combinations to adjust tweeter and mid's level. I carefully examined the circuit, here it is:
An externally hosted image should be here but it was not working when we last tested it.
Btw the crossover is not that much of a hi-end imo, as they claim.. The coils are too close to each other and they re not placed with 90 degrees angle between them to avoid interferences to each other. One of them has core (not an air coil). The woofer's caps are electrolytics ( !!!!!! ) and the tweeter's caps are probably MKT and not MKP. They re radial type at 100V, most MKPs are axial and at 250V minimum but thats not 100% cairtain for all cases. If anybody has info about who is the supplier of crossover parts for Focal, please enlighten me. Thanks a lot.
Thats true but its for frequencies near its natural roll off at the mid section. For examle a driver that its response reaches 4khz, its gonna have an spl bump on axis approx at 3Khz up to 4Khz and then naturally roll off. Off axis it will have a flattest response at the mid area and start falling at 4khz.Bose(o) said:
For example, this is the Focal K2P midbass, the onaxis has a raise near the upper limit of its freq response, but the offaxis is flat. If you check other car midbasses too (you can see many at www.d-s-t.com ), you ll see that the raise is close to the upper end of the freq response. It seems that most drivers loose their ability to radiate well off axis near their upper frequency repsponse limit, this is more known behaviour to tweeters but it applies to woofers too.
An externally hosted image should be here but it was not working when we last tested it.
My case is different. It has an almost flat response until 700Hz, it has a raise between 700 and 1500, it falls about to the same spl level as it was below 700hz and continues up to 5khz.
In fact I did off axis measurements, because I was hoping this was the case, but unfortunately it wasnt.
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