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Old 24th February 2021, 07:57 AM   #2791
ZestClub is offline ZestClub  Thailand
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Awesome!

Thanks.
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Old 24th February 2021, 12:45 PM   #2792
Sharkythefrog is offline Sharkythefrog  Sweden
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Quote:
Originally Posted by Draki View Post
Having been in a similar situation, and received several valuable tips from Kimmo, I might chip in, FWIW:

It seems that you are doing it correctly. Each driver should be treated as a "single way" and measured at 1000 mm (or other, constant, distance) on axis where X,Y and Z are all zero.

For a flat baffle and symmetrical layout, the mic distance is the same for all drivers, but the mic goes up/down (or the mic stays fixed but the box goes up/down) so that it is always at X,Y,Z zero. You measure horizontal 0 thru 180, and since it is symmetrical it can be mirrored for a full 360.

For a stepped baffle, for the stepped-back driver (usually the tweeter) the mic should be brought forward for the depth of the step, so that -again- all X,Y and Z are zero.

For an asymmetrical layout (like yours, with the mid and tweeter offset to the side) you move the mic for the mid and tweeter to the side (for X,Y and Z all zero) but have to measure full - 170 to +180 so that the 360 is realistic, you can't "mirror" it like in the symmetrical layout.

All your drivers are circular, so probably no need to measure vertical, it is supposedly the same as horizontal.
But if you want to you can (that's what I do) lay the speaker on the side and repeat measurements as above, as for horizontal - bcs it is much easier than rotating the box vertically.

Hope this helps a little - Kimmo is watching this so any misinfo will hopefully be waived.
Great explanation. In a transmission line two way with port at the back. As I read it I measure (correct me where I go wrong):
1) from the tweeter at 0 degr vert, 90 degrees BEHIND of the speaker and each 10 degr forward (for example out to the left) until I am totally 90 degrees in front of the speaker (= straight forward of it). Everything at for example 1000 mm distance (and for example ARTA set up as described).
2) then I do a similar thing from on top of the speaker(90 degrees), every x (10? degrees) to the bottom of the speaker (-90).
3) The same thing as bullet 1 but for the midbass
4) The same thing as bullet 2 but for the midbass.
5) Measure nearfield (< 5 cm) from the tweeter
6) Measure nearfield < 5cm) from the midbass
7) Measure nearfield (<5 cm) from the port
8) Migrate 1, 2 and 5 into one 360 degr measure
9) Migrate 3, 4, and 6 into one 360 degr measure
10) The port measure goes xxxx?
11) . . . . . .

What always confuses me when reading of designing and measuring speaker/drivers is that they never seem to be measured and designed (including the xo design) in any room conditions. None of the methods from 0,5 to 4 piradians actually imitate any listening conditions. And if i set the driver position to (as mentioned) to 1250 mm I could select to (as mentioned) "filter out" the floor with cusions, or not. And tons of different other way to do or not do things in the set up. I donīt know how many hours I have spent trying to figure out what can be achieved with different methods and set ups. Quite many, and somewhat not even confused on a higher level. Not easy :-)

ARTA or REW is also a question, so is the choice of microphone. For doing this a very few times I try to find something fairly cost efficient and technically working without toooooo much of struggle.
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Old 24th February 2021, 05:02 PM   #2793
Draki is offline Draki  Macedonia
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^
You need to collect semi-dual channel multi-axis (+/- 180 deg, or at least +/- 90 deg: the below refers to this case) measurements of each drive unit in your 2-way. Presuming that a)the baffle is flat and not slanted; b)the drivers are positioned symmetrical on the vertical; and c) the drivers are circular (no horns, ribbons...).

A rotating stand of about 1,20 m height is needed (or less, depending on the enclosure height - the drivers should be brought at the mid-room height aprx), with a fixed point of rotation at the base plate, so the box' front baffle center line is aligned to the rotation point.

Mic is at 1000 mm from the baffle.

Set the measuring program (ARTA, REW) to 10 deg intervals, from 0 to 90 deg-hor.
You will measure horizontal only. The drivers being circular, it can be assumed that the vertical is same and symmetrical, so you will check the "mirror missing angles" in the options.


Measure first the tweeter, starting with the mic at zero deg (i.e. aiming straight to the dome). After the first (zero) measuring sweep, rotate the stand/speaker to 10 deg, measure....and repeat until 90 deg. NO near measurement of the tweeter!

Reposition the mic carefully so that it is now aiming at the center of the midbass, but make sure the same 1000 mm distance is kept! Starting with zero deg again, repeat the above as for the tweeter.

You have to save these -90 to +90 far field measurements for each driver as explained in Kimmo' preparation for measurements document (please read, and re-read it carefully!). https://kimmosaunisto.net/Software/V...eparations.pdf

The midbass and the port, will be measured also near field, at about 4-5 mm to the dustcap or to the mouth of the port, with signal level decreased typically by 20 dB.

Using Merger tool, the near field of the midbass and the port will be merged with the far field of the midbass. This merged response is what you use in the crossover simulator for the midbass driver.

The tweeter far field response as measured above (no additional action needed) is used in the simulator.

Fed with these measurements, the program will have 180 deg worth of both horizontal and vertical data, since it will fill-in and calculate the missing angles.

These are measurements which can be taken in a normal room. They will show the system response as in anechoic environment. Once in an actual room, the room will inevitably alter the frequency response, specially below Schroeder (typically below 300 Hz). At this point, you have to deal with the speaker-room interaction and possibly do some room equalization. That is indeed a separate subject.

Note that an analog mic (ECM8000, Sonarworks etc) and a decent duplex soundcard (Behringer, Focusrite et al..) is recommended and indeed needed for a semi-dual channel measurements. No USB mic.

Last edited by Draki; 24th February 2021 at 05:07 PM.
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Old 25th February 2021, 04:22 AM   #2794
kimmosto is offline kimmosto  Finland
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Quote:
Originally Posted by Sharkythefrog View Post
None of the methods from 0,5 to 4 piradians actually imitate any listening conditions.
In DIY scene it's not very rare idea that speaker could or should be designed for certain environment (to our home); construction materials and shape of the building, predicted location of the speakers and location of each radiator (driver/port) in the speaker.
Of course that part of sound balancing can be included in crossover design by weighting or preprocessing measurement data captured in anechoic, but this should apply to designs what really require help from some room boundary.

More common goal - especially in commercial scene is that speaker is as universal as possible: does not have to be located very close or very far from the wall(s), works far from the walls and quite close to walls if e.g. compensation for floor dip at mid-range is needed.

The most common and recommended measurement and design method is to make excellent sound source which radiates as healthy sound as possible to available space. Available space for other than flush-mounted wall and corner speakers is full space. Measurement data should be (quasi) full space and compatible with anechoic to enable full perspective to radiation from speaker.

Half space radiation below Schroeder frequency can be predicted with help of power response (e.g. flat power below Schroeder) or some simple thumb rule; tilt up on-axis response at bass range based on own experience or opinions on discussion forums or features of known commercial/diy speakers.

Personally I'm not a fan of radiators requiring boundary reflections because it makes the design more sensitive to room modes and requires certain location which reduces possibilities to find the best overall location. So radiation to full space is weighted in my communication.

Last edited by kimmosto; 25th February 2021 at 04:34 AM.
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Old 25th February 2021, 08:19 AM   #2795
kimmosto is offline kimmosto  Finland
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2.0.62.0 (2021-02-25)

Main
* Added File -> Archive project command.
* Added 'Archive project' settings to External tools and directories group in Options window.

Download 7-Zip from 7-Zip.
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Old 25th February 2021, 11:46 AM   #2796
Sharkythefrog is offline Sharkythefrog  Sweden
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Thanks for your engagement Kimmosto.
Trying to follow.

Quote:
Originally Posted by kimmosto View Post
In DIY scene it's not very rare idea that speaker could or should be designed for certain environment (to our home); construction materials and shape of the building, predicted location of the speakers and location of each radiator (driver/port) in the speaker.
Of course that part of sound balancing can be included in crossover design by weighting or preprocessing measurement data captured in anechoic, but this should apply to designs what really require help from some room boundary.
Ok, can understand this, and some of the pros and cons.

Quote:
Originally Posted by kimmosto View Post
More common goal - especially in commercial scene is that speaker is as universal as possible: does not have to be located very close or very far from the wall(s), works far from the walls and quite close to walls if e.g. compensation for floor dip at mid-range is needed.
And this is I guess where many DYIs not comply with the average listerer as we try at least in some way to get a fairly good environment, and select gears from what might fit in the environment. So when we have the chance we could be to some extent more adaptive to "ourselves", or am I totally wrong here?

Quote:
Originally Posted by kimmosto View Post
The most common and recommended measurement and design method is to make excellent sound source which radiates as healthy sound as possible to available space. Available space for other than flush-mounted wall and corner speakers is full space. Measurement data should be (quasi) full space and compatible with anechoic to enable full perspective to radiation from speaker.
Full Space =free air. Isnīt half space more close to room situation or even quarter space? Or is it just that we measure full space and let the software(s) use algorithms to find out what the best would be for a more room like situation?

Quote:
Originally Posted by kimmosto View Post
Half space radiation below Schroeder frequency can be predicted with help of power response (e.g. flat power below Schroeder) or some simple thumb rule; tilt up on-axis response at bass range based on own experience or opinions on discussion forums or features of known commercial/diy speakers.
Tried to find "schroeder frequency" but only did find a lot of well known "schroeder" men and woman.
"tilt up on-axis-response...." which mean what, that we enhance "bass bost" or whatever the preferense is?

Quote:
Originally Posted by kimmosto View Post
Personally I'm not a fan of radiators requiring boundary reflections because it makes the design more sensitive to room modes and requires certain location which reduces possibilities to find the best overall location. So radiation to full space is weighted in my communication.
I can absolutely understand this choice. Just a question which concerns me the most; the bass port in for example a MLTL leaving the cabinet at the back baffle will get enhanced LF spl with the wall behind the speaker. How is that taken care of, in for example the migration process for the midbass far field, near field and port nearfield measurements?

And another topic. Vertical measurement. Yes the driver can be circualr, but the box isnīt and it will be different distances to the cabinet edge on horizontal and vertical directions. Why is it still ok to just measure the horizontal directions, 10 degree by 10 degree?

Quite a learning curve from Zero on measuring and proper xo design. :-)

Thanks in beforehand anyone/everyone!!!!

Last edited by Sharkythefrog; 25th February 2021 at 11:48 AM.
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Old 26th February 2021, 06:06 AM   #2797
kimmosto is offline kimmosto  Finland
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Quote:
Originally Posted by Sharkythefrog View Post
I guess where many DYIs not comply with the average listerer as we try at least in some way to get a fairly good environment, and select gears from what might fit in the environment. So when we have the chance we could be to some extent more adaptive to "ourselves", or am I totally wrong here?
Both commercial hifi and diy enthusiast are individuals. Arrogance and ignorance about environment and setup are as common in diy as commercial hifi imo. Diy is just a hobby including some resources such as tools and measurement gear, but nothing more by default.

Quote:
Originally Posted by Sharkythefrog View Post
Full Space =free air. Isnīt half space more close to room situation or even quarter space?
This was already answered. No it's not.

Quote:
Originally Posted by Sharkythefrog View Post
Or is it just that we measure full space and let the software(s) use algorithms to find out what the best would be for a more room like situation?
Also this was already answered. Please read and don't make me repeat.
Should be measured to available space so everything not flush mounted in the wall (or ceiling or floor or corner) is full space.

Quote:
Originally Posted by Sharkythefrog View Post
Just a question which concerns me the most; the bass port in for example a MLTL leaving the cabinet at the back baffle will get enhanced LF spl with the wall behind the speaker. How is that taken care of, in for example the migration process for the midbass far field, near field and port nearfield measurements?
If you really decide to do such a design, leave port band e.g. ~3 dB lower to get flat power below 150 Hz, and locate speaker so that balance at listening area is okay. Port signal will be separate and location/material dependent and generate resonances which are not features of healthy concept.

Quote:
Originally Posted by Sharkythefrog View Post
Vertical measurement. Yes the driver can be circualr, but the box isnīt and it will be different distances to the cabinet edge on horizontal and vertical directions. Why is it still ok to just measure the horizontal directions, 10 degree by 10 degree?
Also this has been answered several times in the past.
I don't deny measuring vertical plane, but error is no more than 0.5 dB in power response (small hump at mid-range) so you can handle this by making sure that listening window RMS is flat rather than having significant hump at baffle hump frequency i.e. baffle width ~ wave length.
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Old 26th February 2021, 06:43 AM   #2798
AllenB is offline AllenB  Australia
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Quote:
Originally Posted by kimmosto View Post
Diy is just a hobby including some resources such as tools and measurement gear, but nothing more by default.
DIY will always go further and do more than commercial, and requires harder design work. When commercial plays it safe, customers will be happy even those that have not been trained in setting up.
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Old 26th February 2021, 06:57 AM   #2799
kimmosto is offline kimmosto  Finland
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^That is arrogance and self-deception quite typical in diy.
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Old 26th February 2021, 07:01 AM   #2800
Sharkythefrog is offline Sharkythefrog  Sweden
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Thanks a lot Kimmosto,
Sorry for get you feel that you are repeating yourself. As a 30+ years of project/program management it’s just a habit of clear anything that has even a microscopic chance to be misunderstood. I think I am getting at least a little little bit of understanding of how it works. It might be that the Toyota way is applicable even here. The managers should have been on the production floor to have seen by own eyes to understand the production. Maybe it’s time to go to the floor. Thanks!!
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