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Small midrange in 3 way system

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Digital_Thor

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@Duke - I chose the DXT - because I found it cheap, very well measuring and broadly used, with lots of experience to draw from. I also heard it in the Kii3 - liked it. But in the Grimm - I found the sound a bit "aggressive". Maybe the rather big 8" Excel driver, is simply not good for crossing over to the DXT - even with the rather wide baffle.
I have been tempted to make a special waveguide for the 26ADC or the like. But the DXT seemed fine for the job - and ready build.
Your point is very valid and can surely experiment with at different crossover point. At the moment I kinda just "stole" the idea from Heissmann and found it great sounding and did not think about changing anything at the moment. I think I need to make some better measurements, to properly find the best crossover. Also a higher crossover point... surely needs a small midrange :)
 
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Digital_Thor

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bigjacko

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puppet

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It is a good website. Was looking at their measurements of the big Supravox ... man, they are in a class by themselves.
 

B&WTube

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Everyone suggesting the Scanspeak 10UF- you like it better than the 12MU and 12M??
 

Tangband

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This is an interesting thread :).
Going three-way active in a standmount loudspeaker with a 6 1/2, 3 and 0,75 inch driver can lift the perceived soundquality , with less IMD distortion . No waveguide needed .

My wote for a 3’ is this driver , from German eton .
https://hificompass.com/en/speakers/measurements/eton/eton-3-400a825mg

https://www.eton-gmbh.com/fileadmin/user_upload/Produkte/Home-Hifi/Symphony/3_400_A8_25MG.pdf

This unit is apparently used by Australian company Legend Acoustics in their active top - model.
 

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headshake

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That eton out of production. I was looking for it when I made my 3way. :p I did find a guy in china selling them for $$$$. One downside (based on random internet posts) seems to be the cone can get messed up by humidity. The $$$$ eton arcosia seems to have a coating that solves the problem.

It seems like so many drivers ring for a few ms in the 500hz-1khz range. Just a few woofers act like a dome mid. Is it the high Bl parameter?
 

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PKAudio

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I have worked and listened to all of them, but in different projects.
They all are my favourite, and they all fit different projects due to cost, sound character, and the look differences.
12MU is great with Bliesma and 18WU. Crispy, vivid sound. I used it also with R3004 with very good result as well.
12M sounded very natural and relaxed in my upgraded Ekta grande.
10F, this one I am trying to get sound right in one of current projects, so far it sounds very promising, but there is still the work to be done, the sound is a bit forward.

Everyone suggesting the Scanspeak 10UF- you like it better than the 12MU and 12M??
 

bigjacko

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That eton out of production. I was looking for it when I made my 3way. :p I did find a guy in china selling them for $$$$. One downside (based on random internet posts) seems to be the cone can get messed up by humidity. The $$$$ eton arcosia seems to have a coating that solves the problem.

It seems like so many drivers ring for a few ms in the 500hz-1khz range. Just a few woofers act like a dome mid. Is it the high Bl parameter?
How does humidity mess up the cone? I have wood pulp cones for my speaker too, wonder how do you tell it.
 

ctrl

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An interesting thread!
Give my two cents :eek:

So if the SeasDXT is set as a tweeter, then a 3'' cone driver will not fit, or cause poor directivity. A 3'' cone driver radiates too wide.

If the goal is to achieve a uniformly narrowing dispersion, then 4'' is IMO the limit.
Here is a project with the SeasDXT and 4'' midrange driver.
Horizontal FR and sonogram are normalized to the axis frequency response (+-90°), -6dB limit is from orange to yellow:
1629625653014.png 1629625669827.png
Correctly executed, you get a uniformly narrowing radiation. The transition from the 4'' driver to the DXT in the horizontal radiation is present (1-2kHz range) and should be balanced.

If you want a more even directivity, then combining it with a 6'' or 6.5'' woofer is still okay - like Rick's Directiva project does, for example.
Horizontal FR and sonogram are normalized to the axis frequency response (+-90°), -6dB limit is from orange to yellow:
1629626090480.png 1629626115481.png
This provides a uniform, slightly narrowing radiation. The range 5-10kHz is strongly influenced by the cabinet width at the height of the DXT.

When using an 8'' woofer you get some directivity problems, because then the baffle width will get to the DXT (and the crossover frequency has to be low).


I chose the DXT - because I found it cheap, very well measuring and broadly used, with lots of experience to draw from. I also heard it in the Kii3 - liked it. But in the Grimm - I found the sound a bit "aggressive". Maybe the rather big 8" Excel driver, is simply not good for crossing over to the DXT - even with the rather wide baffle.

The directivity of the two speakers in the range 1-4kHz is very different. The Grimm radiates broadly in the range 1-4kHz and narrows the radiation, like the Kii, to higher frequencies.

Because the crossover frequency of the Grimm LS1 is around 1.2kHz, the sound power in the range 2-4kHz is high. To compensate for this, the axial frequency response would have to show a slight dip in the range 1.5-3.5kHz - it does not.

In contrast, the Kii already shows a narrowing radiation from 1kHz upwards and the fact that the crossover frequency is at 2.2kHz reduces the sound power due to the vertical cancellations in this range.

This might IMO explain your listening impressions.


Simulation of Grimm LS1 tweeter only, horizontal FR and sonogram are normalized to the axis frequency response (+-90°). Crossover frequency in the LS1 is around 1.2kHz. So the above 1.5kHz the directivity is represented by the tweeter.
1629627887154.png 1629627669194.png

Real measurement of the Grimm LS1 horizontal 0-45°:
1629628230746.png
Source

Kii speaker. Horizontal sonogram normalized to the axis frequency response (+-90°). Crossover frequency is around 2.2kHz.
1629629607945.png
Source
 
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Digital_Thor

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The combination of DXT and a 5" Wavecore in Heissmann's DXT-MON, looks really good compared to these.... but I think that the scale are not equal.. so that comparisons are difficult:
directivity_hor.png
 

ctrl

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The combination of DXT and a 5" Wavecore in Heissmann's DXT-MON, looks really good compared to these.... but I think that the scale are not equal.. so that comparisons are difficult:

Exactly, it's no problem to scale your example to about +-90°:
1629644333446.png
The -6dB line is easy to see and can now be better compared with my previous examples.

But there is another crucial difference. The sonograms of Heissmann are, at least it is not stated anywhere, not normalized to the axial frequency response. So it reflects the radiation of the speaker with the on-axis corrections. The normalized sonograms show the directivity (which can't be changed) of the speaker - it shows how much thought the designer put into the design.
The better the directivity of a loudspeaker, the less corrections have to be made to the on-axis FR so that it sounds tonally okay.

Directiva -> normalzied, not normalized example crossover
1629699635972.png 1629699662415.png

4'' + DXT example -> normalized, not normalized (after crossover fine-tuning)
1629699783132.png 1629699806380.png

4'' + DXT not so good example -> normalized, not normalized (after crossover fine-tuning)
1629700222190.png 1629700298951.png

Bad directivity examples of normalized speaker (-6dB yellow/green), one doesn't want abrupt changes in directivity
1629701320137.png 1629701571826.png
 
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Digital_Thor

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Ordered a pair of SB MW13TX-4 after testing a pair of MW16TX at a friend's place. I believe the 5" would fit my build better. I will return with my findings as soon as they arrive :)
 

Keith Conroy

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Ordered a pair of SB MW13TX-4 after testing a pair of MW16TX at a friend's place. I believe the 5" would fit my build better. I will return with my findings as soon as they arrive :)
I think you will really
like the detail of the TeXtreme cone material especially for the mid range...................
 
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Digital_Thor

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I think you will really
like the detail of the TeXtreme cone material especially for the mid range...................
Yes, I think so too. Ordered a pair of SB26ADC too, to see if they can compete with my SEAS DXT, when paired with an Augerpro waveguide. So now I just need to figure out which waveguide to go for. The oval ones seem really tricky to make cut-outs for in the cabinet - but they do seem to be a smart choice because you can have a good horizontal dispersion down low, and a still keep a relative small CTC with the midrange.
 
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Digital_Thor

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One of my friends bought both the MW16TX and the Bliesma T34B. I then brought my little top cabinet with a Seas DXT and Dayton RS125. We then tried to compare and match different combinations to see where there was a real difference and what made sense to me.
The DXT+RS125 works really well for me, but I do hear a clear advantage in the Textreme. What we did, was putting my little speaker upside down on top of the Textreme midwoofer, to mimic that combination. Two things I especially noticed, was that the DXT create a better stereo image with a more clear/clean phantom image of singers. The Textreme simply added a more open sound stage compared to the RS125, where you heard the recorded acoustics in the music fade out in front of you... sounded more realistic.
The Bliesma has the dome very forward in the tweeter, which to me seems like it radiates the sound more wide, making it difficult to compare it to the DXT. It might be more dynamic and open.... but to me, the more important place to start, is a great midrange and a controlled dispersion tweeter - since a lot of the "openness" in sound, to me, comes from the upper midrange and lower tweeter... not the upper tweeter.
I simply had to buy the SB26ADC too, because I have to try it with a Augerpro waveguide to see if it performs as good as the data suggest :)
https://www.somasonus.net/sb-acoustics-sb26
 
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Digital_Thor

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Been playing around a week with my new little MW13TX. Had to make some adapter rings for my cabinets, since the driver is 132mm and not 150mm which the cabinet was build for - testing purposes are fine for this though :) Until now, it plays really nice and much more open than the Dayton. Less EQ is needed since the breakup is less severe, and I can hear the recording space much more easily in music - which is what I call more open. Maybe it's just the added detail of the upper midrange.
Sorry about the rough edges. They were done with a handsaw on a terrace at a hifi-meeting - after 2 beers :p
DSC_4795.JPG
 
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