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Small 2-way speakers with linear on-axis and power response characteristics (Scan Speak and SB Acoustics drivers). H&V off-axis measurements included

For anyone interested, I put my model for 3D printing the boxes, some perf boards, and the ports on Makerworld. This has the benefit of being now the 2nd print with a bunch of revisions to make them print a lot better.
 
Hey all, I think I have something up with my build. Tweeter seems off. I can hear what sounds like crackling and poping at times coming from the tweeter. At other times it is not present. I have never done a proper spin scan but would be willing to learn/try

In room measurement psy smoothing umikc mic

In room measuremnet 1/48 smoothing umik mic

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HighFutility said:
Hey all, I think I have something up with my build. Tweeter seems off. I can hear what sounds like crackling and poping at times coming from the tweeter. At other times it is not present. I have never done a proper spin scan but would be willing to learn/try
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Both speakers exhibit the crackling and popping? Can you duplicate or is it completely random?
 
Hey All,

Hoping to build the cabinets this week. Did you guys do rabbet joints for the panel edges?
 
carbidetooth said:
Both speakers exhibit the crackling and popping? Can you duplicate or is it completely random?
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Update: The tweeter stopped outputting sound. I took it apart, wired it back up, and took the same measurement. Crackling seems to be spontaneous. I have only built one speaker so far. I can hear the crackling during the rew sweeps.

Edit: Probably the last high gloss speaker build I do. Total PITA.
 
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XMechanik said:
I've been trying to make design of a small, simple-to-build and inexpensive speaker that would not need a sub at least for music listening at moderate spl levels. No need for high power. This is third approach, code name "Mechano23". I'm sharing the results and VituixCad project file (LINK) with off-axis measurements in both planes so anyone could play and experiment.

Drivers used in the design:
  • Scan Speak H2606/920000 LINK
  • SB Acoustics SB13PFCR25-4 LINK
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What would be the equivalent DSP settings to replace the crossover, if the speaker was built as active?

Say, with a miniDSP:-
- driver delay
- driver attenuation
- crossover frequency and slopes
- parametric EQ
 
HighFutility said:
Update: The tweeter stopped outputting sound. I took it apart, wired it back up, and took the same measurement. Crackling seems to be spontaneous. I have only built one speaker so far. I can hear the crackling during the rew sweeps.

Edit: Probably the last high gloss speaker build I do. Total PITA.
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Not sure how to interpret "spontaneous" but it would seem you've got a faulty tweeter. You only have the one?
Would certainly agree about high gloss finishes. Easily the most demanding when it comes to painted finishes.
 
carbidetooth said:
Not sure how to interpret "spontaneous" but it would seem you've got a faulty tweeter. You only have the one?
Would certainly agree about high gloss finishes. Easily the most demanding when it comes to painted finishes.
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I'd also try taking a 1m measurement to get closer to anechoic. But, that rise isn't right. You can see the woofer starting to roll off at the crossover. There's supposed to be a bit of a bit of a peak at 13k or so -- you've got that. But, I'm guessing something is up with one of the caps or the inductor in the tweeter circuit. I can't fire up VirtuixCAD at the moment to try to replicate, but check to see that you didn't do something like swap the two caps (the 3.3 and the 2 uF) or that you didn't swap the order of the 15 ohm and the 3.3 cap.
 
Maybe try measuring the impedance? That should confirm everything is wired correctly. I used LIMP and the PC built in sound card. Can also use REW I think but I haven't tried that. You just need to make a simple jig with a 100 ohm resistor. see :


Figure 3.1 is what I used but with a 100 ohm resistor.
 

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It doesn't seem to be a swapping of parts. I can get similar responses though by opening a number of components in the woofer circuit. It may not be that the tweeter is off here. If you have a look at the images on p1 of the CAD, you can see the tweeter does have an upward slope, so it may be that it's the woofer circuit too low. If you've got a bad solder joint in there somewhere, you might a) hit the crackling and b) effectively disconnect a cap or inductor.

I'd look to the 6.8 uF, 27 and 18 uF guys first. Here's what happens if one end of the 27 uF isn't connected.

Oh, and try disconnecting the woofer and tweeter in separate runs. Do either of them look wonky? See how the orange trace here for the woofer is clearly ... off?

1742435819143.png
 
While building my second pair (my son got the first pair), I decided to document it so that others new to building might give it a try. It uses 3D printed boxes, so no woodworking needed. I've got the first 3 parts of the series up, on: 1) Why the Mechano23? 2) 3D printing? Really?, and 3) Crossover part purchasing. Zero idea if anyone is interested, but it's a fun distraction ;)
 
celstark said:
While building my second pair (my son got the first pair), I decided to document it so that others new to building might give it a try. It uses 3D printed boxes, so no woodworking needed. I've got the first 3 parts of the series up, on: 1) Why the Mechano23? 2) 3D printing? Really?, and 3) Crossover part purchasing. Zero idea if anyone is interested, but it's a fun distraction ;)
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Well done! I'm very recently into the 3D printing world and might just take this on as a learning project. Thanks for your efforts!
 
celstark said:
It doesn't seem to be a swapping of parts. I can get similar responses though by opening a number of components in the woofer circuit. It may not be that the tweeter is off here. If you have a look at the images on p1 of the CAD, you can see the tweeter does have an upward slope, so it may be that it's the woofer circuit too low. If you've got a bad solder joint in there somewhere, you might a) hit the crackling and b) effectively disconnect a cap or inductor.

I'd look to the 6.8 uF, 27 and 18 uF guys first. Here's what happens if one end of the 27 uF isn't connected.

Oh, and try disconnecting the woofer and tweeter in separate runs. Do either of them look wonky? See how the orange trace here for the woofer is clearly ... off?

View attachment 437557
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I will run some tests tonight, but my pcb setup looks like this.


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Yes did you sand or scrape off the enamel from the inductor leads before soldering? Also it's better to have the cable tie "knots" on the component side of the PCB. Then you can avoid using PCB mounting spacers.
 
HighFutility said:
I did not sand it off on any of them. Inexperienced.
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Ok in that case get a desolder pump and some desolder wick. Slowly and carefully remove the inductors, sand/scrape the last 3mm or so of the leads to remove the enamel and reinstall them. You can use solder wick to carefully clean up the PCB holes if necessary but go easy or tracks may lift.

 
wineds said:
Ok in that case get a desolder pump and some desolder wick. Slowly and carefully remove the inductors, sand/scrape the last 3mm or so of the leads to remove the enamel and reinstall them. You can use solder wick to carefully clean up the PCB holes if necessary but go easy or tracks may lift.

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One step ahead, I took it apart and put the speakers back together. I ran a sweep much better, but the tweeter crapped out on me. Put in the second tweeter, and voila! It's alive!

Does anyone have experience with a warranty on something like this? I'm located in Canada, but I ordered from Sound Imports EU. I am assuming by the time I pay to ship it back and the new ones get to me It will probably cost the same to just order new ones.
 
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