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Multi-Way Conventional loudspeakers with crossovers

Seas L15RLY/P with Morel DMS30s in Visaton WG148R
Seas L15RLY/P with Morel DMS30s in Visaton WG148R
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Old 25th December 2017, 03:33 PM   #11
Zvu is offline Zvu  Serbia
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Quote:
Originally Posted by peterbrorsson View Post
Zvu,
I buillt the Visamon 170 from HobbyHi-fi, but with active crossover. I'm not at home right now, so can't send any measurements from Hobby Hi-fi + I don't have any possibilities to make measurements, but it make sense that if resonances are decreased by notches, distortion goes down. At least if resonances is corresponding to them....

Peter

Unfortunately, it doesn't work that way.

If you notch out the resonance peak, it decreases the distortion at that particular frequency where the notch is - for as much decibels as the fundament. 3rd and 5th distortion peaks lower in frequency, that are product of that breakup, remains and must be dealt separately at that particular frequency.

I have quite a few HobbyHifi magazines. Do you happen to know what year and month is it, or the name of project you've made ? Thanks
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Last edited by Zvu; 25th December 2017 at 03:41 PM.
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Old 25th December 2017, 03:58 PM   #12
peterbrorsson is offline peterbrorsson  Sweden
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...name of kit is Visamon 170 and I'm pretty confident they are right. HobbyHi-fi claims when x-over is done correctly, it will reduce distortion and their measurements shows that. Black and white is enough for me at the moment, anyone that can disprove it is welcome😊
Peter
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Old 25th December 2017, 04:40 PM   #13
Zvu is offline Zvu  Serbia
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Quote:
Originally Posted by peterbrorsson View Post
...name of kit is Visamon 170 and I'm pretty confident they are right. HobbyHi-fi claims when x-over is done correctly, it will reduce distortion and their measurements shows that. Black and white is enough for me at the moment, anyone that can disprove it is welcome��
Peter
The project name is Visamon 170. The only version i managed to find is passive. There it is:

Hobby Hifi Visaton Visamon 170 - Speaker KIT without Cabinet Standard kaufen bei hifisound.de

Click the image to open in full size.

Now, the crossover frequency is 2100Hz. That means that someone smart made the crossover for it because from 2KHz to 3KHz there is a large distortion peak. Making 2100 crossover point and quite sharp slope is wise. Here is the pic for distortion measurement from K&T

Click the image to open in full size.
https://s10.postimg.org/6uhvu327t/o_170.png

I can only assume that active version follows the same premises. So, i don't see what is wrong with what i said and what is it that i should disprove ?
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Last edited by Zvu; 25th December 2017 at 04:53 PM.
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Old 25th December 2017, 05:02 PM   #14
peterbrorsson is offline peterbrorsson  Sweden
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...the measurement from klang+ton is totally different. HobbyHi-fi has raw driver and filtered response in same setup and more detailed graphs than klang...
There is no active version published, I've made one myself. I can send you passive article when I'm back home in January...
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Old 25th December 2017, 08:04 PM   #15
Zvu is offline Zvu  Serbia
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I know that the measurement from Klang&Ton is different but it makes more sense than HobbyHifi in this case.

Allow me to explain...

Here is example of distortion mesurements for L16RNX from K&T and Hobby-Hifi. While we can not compare levels of distortion, we can compare general trends of distortion.

L16RNX frequency response:
Click the image to open in full size.

K&T distortion measurements:
Click the image to open in full size.

Hobbyhifi measurements:
Click the image to open in full size.

Now, since there is cone breakup at 5KHz at measurements (factory, KT and HobbyHifi all measured it correct) there will be 3rd harmonic peak at roughly 1666Hz and 5th harmonic peak at 1000Hz. K&T shows only HD2 and HD3 so there is quite visible peak of HD3 at that frequency. Hobby-Hifi on the other hand shows 2nd, 3rd and 5th - and while there are no peak at 1666Hz on 3rd harmonic, there is quite visible peak at 1000Hz on 5th harmonic. If breakup propagates as 5th harmonic, it will as 3rd harmonic also. All of that means that it failed to show real picture somehow or HobbyHifi measures different kind of L16RNX than everyone else (since similar distortion profile to K&T is visible in Zaphs measurements).

Now, back on AL170 - that is the same thing. They show quite benign distortion profile, while reality is different. Here is measured distortion from an independent party:

Click the image to open in full size.

3rd distortion peak is quite visible there too so it makes measurements of K&T much more reliable than Hobby Hifi in this case.

This is not to say that all distortion measurements from HobbyHiFi are bad - these are exceptions because in most cases they measure it properly, but every once in a while they don't. I don't know the reasons for it, it just is.

As for distortion behaviour when you notch out the resonance peak - you'll just have to believe me that peak in HD3 at 2KHz will not disappear when you put notch filter on 6KHz cone resonance and flatten it out. Or not

Merry Christmas
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Last edited by Zvu; 25th December 2017 at 08:21 PM.
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Old 25th December 2017, 08:15 PM   #16
peterbrorsson is offline peterbrorsson  Sweden
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Perhaps, I will send you the raw and filtered response anyway😊

Cheers!
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Old 25th December 2017, 08:18 PM   #17
Zvu is offline Zvu  Serbia
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By all means, please do.

I am quite curious
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Old 26th December 2017, 12:04 PM   #18
Mario Pankov is offline Mario Pankov  Europe
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Seas L15RLY/P with Morel DMS30s in Visaton WG148R
No, I mean have you investigated a way to mitigate it? Perhaps cone treatment may do the trick, have you attempted anything like that?

In general it should not be audible in this design due to the steeper crossover and well designed crossover.
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Old 26th December 2017, 01:21 PM   #19
Zvu is offline Zvu  Serbia
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I have not. I know of one way to reduce the breakup - which would reduce the 3rd order distortion peak but i am reluctant to try it because after that there is no going back

Here's the thing. While i watched some interviews that John Atkinson did, i ran into an interview with Laurence Dickie - designer in Vivid Audio. He explains how they've managed to move the breakup higher in frequency. Adding carbon rings in three specific places. I can do that but when i do it, if i messed up, that's it.

I'm in the search for another pair of L15RLY because i want to try that. If i manage to find a decently priced pair - i'll report back with the results.
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Old 13th January 2018, 05:50 PM   #20
Zvu is offline Zvu  Serbia
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I've been playing with these a bit more but haven't had the time to try it yet. Everything is the same, phase response it a tiny bit better. This is achieved by ditching 1.5 ohm resistor on the midwoofer crossover and some values changes of few components - but that's it. This is hairsplitting and i'm not even sure that one could hear the difference - but why wouldn't we do it if we can.

Click the image to open in full size.

https://s14.postimg.org/569ci9n9t/output_7wt_Dw_K.gif
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Last edited by Zvu; 13th January 2018 at 06:08 PM.
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