Hi everyone. I need help in measuring my Mezzo Utopias with new focal drivers to adjust the crossover.
I decided to biamp them. So I bought a Crown 1502 to use for the bass and I will use my Aethetix Atas for the mid-tweeter sections.
The current status is that I have new Woofers, the ones used in their latest Utopia Scala speakers, and replacement midrange drivers from the Mezzo era but the ones used in the Grand Utopia then, and I have had my tweeter replaced by focal, with a titanium I think, since they had no spares for my tweeters.
This is the state of the drivers. I also purchased both Parts Express DATS and Omnimic V2 measuring systes, so that I can take proper measurements and be more sure about what I am doing. So the expert measuring system is at hand, I just need the brains(which I do not claim to possess...).
As I am using a Metric Halo Lio-8 3D as both pre-amp and DAC, and since it has the capability to act as anything soundwise really, including a crossover, I was thinking of using it for this task.
Initially I was thinking of connecting the drivers on the cabinet but without any crossover and to test them in place (including the effect of the box), using the DATS and the Omnimic, to have all the right parameters. I could change the parameters of one speaker using three of the four channels availiable in my amplifiers, until I get the right curve, so that I can know the best cutoff points between the three drivers. I will then keep the crossover for the bass and the output for it and make a crossover for the mid and tweeter without the need to cut the low for the mid, since I will be cutting it using a the Lio-8. In this way I can build a crossover with minimum components and exact to my speakers.
Since I have no experience in this, I would very much appreciate it if you can give me some guidance as to what to do. If you can help I can send you the characteristics and you could perhaps help me with the design of the crossover.
Initially I read various articles on measuring the speaker response and I have a couple of questions:
1. Do I take near field measurements of all, the bass(and port), the mid and the tweeter, to reduce the effect of room interaction, or do I use the transient response curve for the mid/tweeter to identify room interaction and separate the useful part of the frequency response of each driver and add it up to get the real response of it?
2. In near field measurements, do I measure in the same distance from the center of the drivers for all drivers(so I am limited by the woofer distance which is the largest), or each one within 0.11 times its' diameter which will remove outside interference?
3. If I take measurements at ear level and 1m from the speaker, should I activate one at a time or all together and measure the resulting curve?
Should I also take measurements around this area, moving the mic higher/lower to the right/left?
I am not sure about all this. I have Xsim to input the data of the measurements for the drivers, and I can perhaps then design a crossover. I can perhaps use the crossover that in them as a guide.
If there is another simpler way that I can follow, please tell me. I do feel a bit lost....
I decided to biamp them. So I bought a Crown 1502 to use for the bass and I will use my Aethetix Atas for the mid-tweeter sections.
The current status is that I have new Woofers, the ones used in their latest Utopia Scala speakers, and replacement midrange drivers from the Mezzo era but the ones used in the Grand Utopia then, and I have had my tweeter replaced by focal, with a titanium I think, since they had no spares for my tweeters.
This is the state of the drivers. I also purchased both Parts Express DATS and Omnimic V2 measuring systes, so that I can take proper measurements and be more sure about what I am doing. So the expert measuring system is at hand, I just need the brains(which I do not claim to possess...).
As I am using a Metric Halo Lio-8 3D as both pre-amp and DAC, and since it has the capability to act as anything soundwise really, including a crossover, I was thinking of using it for this task.
Initially I was thinking of connecting the drivers on the cabinet but without any crossover and to test them in place (including the effect of the box), using the DATS and the Omnimic, to have all the right parameters. I could change the parameters of one speaker using three of the four channels availiable in my amplifiers, until I get the right curve, so that I can know the best cutoff points between the three drivers. I will then keep the crossover for the bass and the output for it and make a crossover for the mid and tweeter without the need to cut the low for the mid, since I will be cutting it using a the Lio-8. In this way I can build a crossover with minimum components and exact to my speakers.
Since I have no experience in this, I would very much appreciate it if you can give me some guidance as to what to do. If you can help I can send you the characteristics and you could perhaps help me with the design of the crossover.
Initially I read various articles on measuring the speaker response and I have a couple of questions:
1. Do I take near field measurements of all, the bass(and port), the mid and the tweeter, to reduce the effect of room interaction, or do I use the transient response curve for the mid/tweeter to identify room interaction and separate the useful part of the frequency response of each driver and add it up to get the real response of it?
2. In near field measurements, do I measure in the same distance from the center of the drivers for all drivers(so I am limited by the woofer distance which is the largest), or each one within 0.11 times its' diameter which will remove outside interference?
3. If I take measurements at ear level and 1m from the speaker, should I activate one at a time or all together and measure the resulting curve?
Should I also take measurements around this area, moving the mic higher/lower to the right/left?
I am not sure about all this. I have Xsim to input the data of the measurements for the drivers, and I can perhaps then design a crossover. I can perhaps use the crossover that in them as a guide.
If there is another simpler way that I can follow, please tell me. I do feel a bit lost....
Your very first step is to measure the impedance of mid and tweeter indepenently with DATS. For the mid make sure you measure while in the cabinet. You _could_ measure the woofer, but since you will be using an active crossover, the impedance does not matter anymore for your crossover design.
Set your measurement microphone 1m away from the tweeter axis and measure the 2 drivers independently.
Now you can import each to XSim.
Then the issue is measuring driver distance. For this you'll need to look at OmniMic or online help using interferometry. Use your tweeter as your reference driver and set each driver a distance relative to it. You'll need to do more research, including look at older threads for "measuring driver distance."
Get that far and you'll have lots more questions.
This being a hybrid system, AND the fact that you really have no control over the bass section, you'll be able to avoid some hassles you'd need to do with a true 3-way.
Set your measurement microphone 1m away from the tweeter axis and measure the 2 drivers independently.
Now you can import each to XSim.
Then the issue is measuring driver distance. For this you'll need to look at OmniMic or online help using interferometry. Use your tweeter as your reference driver and set each driver a distance relative to it. You'll need to do more research, including look at older threads for "measuring driver distance."
Get that far and you'll have lots more questions.
This being a hybrid system, AND the fact that you really have no control over the bass section, you'll be able to avoid some hassles you'd need to do with a true 3-way.
Last edited:
:-O !!!! Interferometry!!!! It is already beginning to get complicated. Is this for time alignment? I did find this Driver Offset Calculator . When talking about distance you mean m and w in the schematic they have? My tweeter is in the middle and my mid is on top of and inclined... Can I not just measure the distance since they are where they are? (vertically up from the tweeter and in like a triangle. I suppose there must be a way to measure it with some kind of software if it measures the time delay of the same signal fed to each driver, at 1m in front of the tweeter. Any suggestions?
Why should you measure the distance separately.. can't your microphone measure the time/phase for both drivers by itself, just one measurement each?
He's using OmniMic, which (last I knew of) did not have this feature.
All the test tones come off a CD.
All the test tones come off a CD.
I also have Umik 1and I think I read somewhere that Umik 1 with a software called REW does time alignment. is this so, or do you have any other suggestion with Umik 1 ?
Hi koskot, subscribed to this thread with great curiosity since I also have a pair of Mezzo!
The distance to the driver is not the physical distance to the front of the driver, but instead where the acoustic center is, which is where the sound actually originate from, which is somewhere close to the voice coil. Since it is somewhere inside the driver, best is to measure it acoustically. The calculator you linked to won't be accurate.
Hi jmpsmash, Do you know how to measure it? Mine should be the same as yours, even though I have slightly different drivers, but they should be equal or very close to yours.
Koskot:
This is actually a very simple process. 🙂 Measure the FR of both drivers independently and together.
Import the independent FR into XSim. Then adjust the delay of the mid until the frequency response looks like the measured combined output. I forgot I wrote a blog post about this here:
A Speaker Maker's Journey: LM-1 Testing Driver Distances
This is actually a very simple process. 🙂 Measure the FR of both drivers independently and together.
Import the independent FR into XSim. Then adjust the delay of the mid until the frequency response looks like the measured combined output. I forgot I wrote a blog post about this here:
A Speaker Maker's Journey: LM-1 Testing Driver Distances
Erik's tutorial above is good.
If you need to have more detail, I learned it from this udemy course. Section 8 on XSim has that in detail. It is a good course to go through in general.
Attention Required! | Cloudflare
Also, since you have DATS, would love to see what the TS param of the Scala Evo woofer looks like. Did you get them directly from Focal? how much were they?
Koskot:
Bite the bullet and measure. 🙂 It will be fun, and the esaiest part of the whole process. If you are cheating already you'll not get far. 🙂
Bite the bullet and measure. 🙂 It will be fun, and the esaiest part of the whole process. If you are cheating already you'll not get far. 🙂
Your site and the explanations look excellent and clear. I wish you had told me about it earlier. I would have read everything over the weekend.
Time to study and to test....
Time to study and to test....
OK, I have checked, your original drivers is
tweeter TG
midrange 6W4453
bass 11W6451
so new woofers is 11W6452 or 11W7552DB?
it shoudl not be hard to adjust xover if midrange is the same.
tweeter TG
midrange 6W4453
bass 11W6451
so new woofers is 11W6452 or 11W7552DB?
it shoudl not be hard to adjust xover if midrange is the same.
My tweeters have to Focal and back and they were unfortunately changed because they had no spare parts. The diaphragm is different and looks like titanium and the coil inside too. The rest looks the same. The measurements between my two tweeters is a bit different. Mind you, I made a small line on one of them while trying to put a weight on it to test the VAS parameters with DATS. The parameters I get for the tweeters are fs=1008/1032, Re=6.2/5.952, Le=0.069mH/0.07272 at 10kHz, Qts=0.7295/0.7055, Qes=0.8731/0.8333, Qms=4.434/4.6. To you experienced people, do these look OK? Are they good or should I change my tweeters?
Regarding the Z offset, I discovered that Omnimic has a special procedure to find it (page 45 in the user manual https://www.daytonaudio.com/images/resources/390-792--dayton-audio-omnimicv2-user-manual-5-04.pdf).
Regarding the Z offset, I discovered that Omnimic has a special procedure to find it (page 45 in the user manual https://www.daytonaudio.com/images/resources/390-792--dayton-audio-omnimicv2-user-manual-5-04.pdf).
Wait, you don't need to test any Thiele-Small parameters for tweets! 🙂
Vas, Qms, etc. is only important for drivers where you need to design an enclosure for.
In your case, you are kind of screwed.... 🙂 you have to accept the enclosures on the md and woofer. The tweet has it's own enclosure built in.
So, you only need to measure the impedance and FR. For the mid/woofer you need to measure the impedance in place or it will be inaccurate.
You do have the risk of having less than optimal driver/enclosure matching, but since you are going to DSP everything anyway this is something you can correct in the EQ. 🙂
So, you only need to measure the impedance, frequency response and distance of the drivers. And, I forgot, becuase you are bi-amping, you don't even really care about the impedance of the woofer. That only matters to passive crossover design.
Vas, Qms, etc. is only important for drivers where you need to design an enclosure for.
In your case, you are kind of screwed.... 🙂 you have to accept the enclosures on the md and woofer. The tweet has it's own enclosure built in.
So, you only need to measure the impedance and FR. For the mid/woofer you need to measure the impedance in place or it will be inaccurate.
You do have the risk of having less than optimal driver/enclosure matching, but since you are going to DSP everything anyway this is something you can correct in the EQ. 🙂
So, you only need to measure the impedance, frequency response and distance of the drivers. And, I forgot, becuase you are bi-amping, you don't even really care about the impedance of the woofer. That only matters to passive crossover design.
Last edited: