The tweeter is 6 ohm, equal to the specifications given by seas, only the woofer is 4 ohm instead of 8 ohm as indicated by seas, probably these speakers were part of a series manufactured for a company, outside the catalog.
The thing that worries me most is the tweeter, in the aw7 project with the t18rex, the crossover has been designed for its tweeter that starts to sound more down than the t17rex tweeter I use, I would avoid the risk of damaging the tweeter, do I have to change something to make it sound from a higher frequency, or is it okay all that way?
Thank you.
The thing that worries me most is the tweeter, in the aw7 project with the t18rex, the crossover has been designed for its tweeter that starts to sound more down than the t17rex tweeter I use, I would avoid the risk of damaging the tweeter, do I have to change something to make it sound from a higher frequency, or is it okay all that way?
Thank you.
At low volumes this is OK. For example, you could even use an equaliser to increase the tweeter below its resonance, but with a 1" voice coil you can't do this at high volumes. A tweeter can sound different because of voice coil heating, it can change its volume compared to the woofer while you change the overall volume.
C1 mostly sets the crossover frequency so maybe you want to make this smaller. This does what you ask. (Do you want me to guess? maybe 4u7F)
L1 does the same for the woofer so you could make it smaller than 0m9H.
L2 and C3 will be wrong. Look at the impedance for the t17 and t18 tweeter. The peak is 1000Hz, 2000Hz. L2 and C3 maybe should be halved. Maybe try using an extra series resistor with them to reduce the effect and not cut too much lower treble.
R2 set more or less for the tweeter level.
C2, R1 try disconnecting this. If there is too much high treble, put them back.
C1 mostly sets the crossover frequency so maybe you want to make this smaller. This does what you ask. (Do you want me to guess? maybe 4u7F)
L1 does the same for the woofer so you could make it smaller than 0m9H.
L2 and C3 will be wrong. Look at the impedance for the t17 and t18 tweeter. The peak is 1000Hz, 2000Hz. L2 and C3 maybe should be halved. Maybe try using an extra series resistor with them to reduce the effect and not cut too much lower treble.
R2 set more or less for the tweeter level.
C2, R1 try disconnecting this. If there is too much high treble, put them back.
The phase is connected with the response. The response is different for the T17. It is worth trying to get the response smooth for each driver, and then get them together.
Then that part will become low impedance at lower frequencies. This means C1 and L2 can work as a second order filter.
There is one thing I don't understand: in the loki crossover they use a simple low pass for the woofer and a simple high pass for the tweeter, both second order, the cut is about 800hz for the woofer and about 4500hz for the tweeter, then attenuated with a resistive L-pad, simple, but my problem is that I have a different speaker, with a woofer that can somehow be compared and that perhaps sounds good even with less liters and in a closed box and goes up in frequency enough (on paper at least), but a tweeter that starts playing higher up and that has a resonance frequency that is 1khz above the other.
So if I adopted the high pass filter of the loki, with a cut at about 4500hz, I couldn't care less about the 2khz peak impedance, right?
It seems to me that the aw7 project filter is different in concept: it uses a first order on the woofer with the inductance and uses a sort of first order with C1 also on the tweeter, then adopting corrections with the L2C3 notch and with attenuation of C2R1 and R2, I don't really know which of the two I should prefer, if I had to leave the woofer filtered with only the impedance, then first order filter and use on the tweeter the second order high pass filter of the loki, would a crap come from?
Is it possible to predict the result with some kind of software?
Or do I follow the first route, that is port C1 at 4.7 and half L2 and C3 I hope everything goes well?
I don't have many components to do tests at home, if I have to adjust the values, I have to buy every time ....
Thanks again for your help, if you come to Italy, the pizza is offered by me
When you use a second order electrical filter, there is less problem from changes in impedance, the filter controls them a little better. This might be why the Loki doesn't use L2 C3 across the tweeter like the other crossover does, maybe it just doesn't need it.
A second order crossover is also a good idea for a tweeter to reduce heat and excursion so you can reduce thermal distortions and other distortions. I won't tell you that you must do this however, because I have found success using all different kinds of crossover.
Second order has another use which is less common but is interesting. You can increase the response at the low end, by making the filter peak. Of course you still get the second order rolloff below that. It gives you more control.
Yes, this can make it much easier to understand.
You still need to consider the acoustic issues, the cone breakup, the sound that is not at the front of the speaker. Most simulators do not think about this.
A simulator is excellent for seeing the effect of your filter. It can show you how they work together, and it can show you the acoustic phase so you can change its slope, and decide on polarity.
Hi Allen
Thank you so much for creating this tutorial thread. Yes am a newbie to speaker building.
I've got this JBL 2432H compression driver fitted with a RCF 94H CD horns. Looking into testing it out at 630hz with 2nd order XO. Issue at hand is the data for the compression driver is nowhere to be found. All I know is the fs is 500hz. The horn itself is also design to load the driver down to 500hz. All that I can find is someone over at AVS forum has taken some measurements. Would appreciate your kind advice pls.
Thank you
Thank you so much for creating this tutorial thread. Yes am a newbie to speaker building.
I've got this JBL 2432H compression driver fitted with a RCF 94H CD horns. Looking into testing it out at 630hz with 2nd order XO. Issue at hand is the data for the compression driver is nowhere to be found. All I know is the fs is 500hz. The horn itself is also design to load the driver down to 500hz. All that I can find is someone over at AVS forum has taken some measurements. Would appreciate your kind advice pls.
Thank you
Can you measure the voice coil with a multimeter? You can see if it is an 8 ohm driver. The meter should say 6-7 ohms. Maybe this is written on the back of the driver?
A compression driver has a larger impedance peak, especially when used with a horn that is loading to fs. There may be other concerns with both the loading and size so I think maybe this horn is better crossed higher than 1,000Hz.
A compression driver has a larger impedance peak, especially when used with a horn that is loading to fs. There may be other concerns with both the loading and size so I think maybe this horn is better crossed higher than 1,000Hz.
The impedance peak with a compression driver can be steep and complex, maybe a double peak. If you work without measurement you could use RLC to remove the peak in a chunk, or maybe reduce below 8 ohms. If that sounds OK.
If you want to fix it completely, you can use measurements. Sometimes you need 2 RLC for this.
The insertion loss is 0dB for both types of filter in the passband. After this, the inductors have some resistance which has only a small effect. Both types of filter are usually used to -6dB at the cutoff because it works best with most speakers.