Hey everyone.
I'm going to build a 3-way speaker based on
woofer: Tang Bang W5-1138SMF, 5.25" subwoofer driver
mid: Visaton B80
tweeter: Vifa XT25TG30-04
Both internet and simulation give 12 liter inner volume and ~35Hz port
The overall design is like these Xavian: 12mm oak, rounded sides, slot vented but with 3 drivers
So my questions are:
1) Any advice on distance between twitter and mid? Cross will be set to ~3kHz, that gives ~11cm wavelength.
2) Is there any rule-of-thumb for twitter positioning on a front plate? Symmetric to sides but smaller distance to the top? All distances different?
Does twitter position makes a big difference if all corners are rounded?
2.5) Twitter in the middle? Any known drawbacks here?
3) Slot-port. Compared to the rounded port this type has more friction. What area overhead should I plan to compensate for that?
4) Other critique and advises are welcome.
I'm going to build a 3-way speaker based on
woofer: Tang Bang W5-1138SMF, 5.25" subwoofer driver
mid: Visaton B80
tweeter: Vifa XT25TG30-04
Both internet and simulation give 12 liter inner volume and ~35Hz port
The overall design is like these Xavian: 12mm oak, rounded sides, slot vented but with 3 drivers
So my questions are:
1) Any advice on distance between twitter and mid? Cross will be set to ~3kHz, that gives ~11cm wavelength.
2) Is there any rule-of-thumb for twitter positioning on a front plate? Symmetric to sides but smaller distance to the top? All distances different?
Does twitter position makes a big difference if all corners are rounded?
2.5) Twitter in the middle? Any known drawbacks here?
3) Slot-port. Compared to the rounded port this type has more friction. What area overhead should I plan to compensate for that?
4) Other critique and advises are welcome.
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This is a nice project in perspective @RuSound 😎
1/ mid-to-tweeter distance : the closer, the better - if doable, of course.
V.Dickason (in "The Loudspeaker Design Cookbook") recommends for 3KHz a max value of d=C/Fc=344/3000=0.114m=114mm. You mention 11cm, which is already correct, but going under will normally improve your polar vertical dispersion if you don't listen in axis, giving a better homogenity or "blend".
2/ and 2.5/ /tweeter position : asymetrical can help - again, if doable.
This will tame the baffle step effect, and reputedly give a better sound image... Same point for the rounded corners, but the rounding radius must be very large. V.Dickason mentions a 50mm radiused face which showed very little effect vs. a square angle face.
3/ Port shape : round or flat, both works...
As long as you have the required Sv vs. the size of the speaker, indeed. Again, V.Dickason mentions a lower limit at Sd/9, Sd/4 being a good choice.
He also gives these average values :
Speaker------Port
4"------------ 1" min
4-5"---------- 2"
6-8""--------- 3"
8-12"-------- 4"
12-15"------- 5-6"
Below I used a "Jensen-Onken" type of vent for a small 4" woofer with success :
The vent width is 10mm, length is 192mm, total Sd is 11.34cm2 (eq. dia. 38mm) because 3 vents on the 6 are plugged.
On those 3-way bookshelf enclosure, the port is 63mm x 278mm, the woofer is a 7", and the neat volume is 22L. you note that I did not placed the tweeter as close as possible to the midrange... For aesthetical reasons !
For my curiosity, I'll have a look to the speakers you plan to use with 12L neat volume tuned to 35Hz. It will certainly be a nice/cool/small shelf enclosure ! 🙂
A+!
1/ mid-to-tweeter distance : the closer, the better - if doable, of course.
V.Dickason (in "The Loudspeaker Design Cookbook") recommends for 3KHz a max value of d=C/Fc=344/3000=0.114m=114mm. You mention 11cm, which is already correct, but going under will normally improve your polar vertical dispersion if you don't listen in axis, giving a better homogenity or "blend".
2/ and 2.5/ /tweeter position : asymetrical can help - again, if doable.
This will tame the baffle step effect, and reputedly give a better sound image... Same point for the rounded corners, but the rounding radius must be very large. V.Dickason mentions a 50mm radiused face which showed very little effect vs. a square angle face.
3/ Port shape : round or flat, both works...
As long as you have the required Sv vs. the size of the speaker, indeed. Again, V.Dickason mentions a lower limit at Sd/9, Sd/4 being a good choice.
He also gives these average values :
Speaker------Port
4"------------ 1" min
4-5"---------- 2"
6-8""--------- 3"
8-12"-------- 4"
12-15"------- 5-6"
Below I used a "Jensen-Onken" type of vent for a small 4" woofer with success :
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
The vent width is 10mm, length is 192mm, total Sd is 11.34cm2 (eq. dia. 38mm) because 3 vents on the 6 are plugged.
On those 3-way bookshelf enclosure, the port is 63mm x 278mm, the woofer is a 7", and the neat volume is 22L. you note that I did not placed the tweeter as close as possible to the midrange... For aesthetical reasons !
An externally hosted image should be here but it was not working when we last tested it.
For my curiosity, I'll have a look to the speakers you plan to use with 12L neat volume tuned to 35Hz. It will certainly be a nice/cool/small shelf enclosure ! 🙂
A+!
Last edited by a moderator:
Thanks!
I actually found a good guidelines right after I made a port here.
Loudspeaker Enclosure Design GuidelinesI will also consider cutting a "lens" from a tweeter front plate to set it closer to the mid.
https://sound-au.com/articles/enclosures.htm#s3
12 Liters is not that small actually. In reality this will be 12 l + port volume + material thickness volume + 1-2 l for mid + I'll probably make an inclined top from inside to reduce vertical standing waves
>>V.Dickason mentions a 50mm radiused face which showed very little effect vs. a square angle face.
Well, (similar to your speakers) I can only do ~12mm radius at max because of the material thickness. Large radius will also look bad on such a small speaker.
I will make a post here when I'm done.
I actually found a good guidelines right after I made a port here.
Loudspeaker Enclosure Design GuidelinesI will also consider cutting a "lens" from a tweeter front plate to set it closer to the mid.
https://sound-au.com/articles/enclosures.htm#s3
12 Liters is not that small actually. In reality this will be 12 l + port volume + material thickness volume + 1-2 l for mid + I'll probably make an inclined top from inside to reduce vertical standing waves
>>V.Dickason mentions a 50mm radiused face which showed very little effect vs. a square angle face.
Well, (similar to your speakers) I can only do ~12mm radius at max because of the material thickness. Large radius will also look bad on such a small speaker.
I will make a post here when I'm done.
Sure, @RuSound 😎 ! And thanks for the link... 😉
I don't understand or I miss something in your calculation 😕 :
In reality this will be 12 l + port volume + material thickness volume + 1-2 l for mid + I'll probably make an inclined top from inside to reduce vertical standing waves.
I would calculate laike this :
+12L gross internal volume
- port volume (except if it is laminar type, and then excluded from the volume by cab design)
- 2L for mids cavity
- room taken by the speaker structure
+ room left by the opened baffle for the speakers
- room taken by the Xover, bracings (if there is)
0 for the stuffing material, because it more or less increase the acoustic volume, depending on its quantity and placement (by reducing the sound speed through it).
So you have less than 12L for your neat volume, IMHO...
Correct me if I interpreted falsely your description... 😉
A+!
I don't understand or I miss something in your calculation 😕 :
In reality this will be 12 l + port volume + material thickness volume + 1-2 l for mid + I'll probably make an inclined top from inside to reduce vertical standing waves.
I would calculate laike this :
+12L gross internal volume
- port volume (except if it is laminar type, and then excluded from the volume by cab design)
- 2L for mids cavity
- room taken by the speaker structure
+ room left by the opened baffle for the speakers
- room taken by the Xover, bracings (if there is)
0 for the stuffing material, because it more or less increase the acoustic volume, depending on its quantity and placement (by reducing the sound speed through it).
So you have less than 12L for your neat volume, IMHO...
Correct me if I interpreted falsely your description... 😉
A+!
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