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Multi-Way Conventional loudspeakers with crossovers

Thoughts on the SB Acoustic SB12PAC25 and ideal tweeter and box?
Thoughts on the SB Acoustic SB12PAC25 and ideal tweeter and box?
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Old 1st June 2018, 05:06 PM   #11
Qts is offline Qts
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Raw responses of the Micro Kit drivers 0, 30 and 60 degrees. 1m, no smoothing, gated (about 4 ms).
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Old 2nd June 2018, 08:37 AM   #12
rabbitz is offline rabbitz  Australia
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Pascal

Here's a quick mod you can try using existing components to give 2nd order on the tweeter and have a better overlap between drivers.

C2 remove 10uF and add link, C1 replace 3.3uF with 10uF, reverse tweeter polarity to -ve polarity.

This should remove any dip at the xo point and drops the xo point down to around 3100Hz.
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Old 3rd June 2018, 05:47 PM   #13
Gropascal is offline Gropascal  France
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Hi Rabbitz,

Many thanks for your suggestions, I sure will try.
I made another try, by changing the lowpass inductor from 0,68mH (as indicated in kit manual) to 0,54mh, this fills the "lack" between the speakers, without affecting their already shown qualities.

But I am really interrested in the second order hipass you propose, to "symetrize" cut off slopes, I guess that will improve imaging.

All in all, these really tiny speakers are really very good sounding, but the pleasure of diy is also in tweaking, specially with the help and suggestions of diy mates.

Will let you know about the progresse of my experimentations...
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Old 12th June 2018, 11:53 AM   #14
Gropascal is offline Gropascal  France
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Hi Rabbitz and everybody,


I have try what you suggested in your post, and I tried a lot of adjustments without finding a one that was really satisfying ...
...then I became aware of one thing, a beginner's fail : the positioning of the speaker.


As bookshelf speakers, they where installed on a shelf (!)
Too high a shelf : approx. 1.5m from ground, tweeter level 15cm higher


So I quickly made an appropriate stand, placing tweeter a ear level, and then everything changed.
No transition miss, no crossover tweak needed (I returned to SB design), and a very pleasing speaker to listen to. Really surprising for such a tiny thing, and getting even better as running in.


I am really sorry for wasting your time with my questions and a bit ashamed having been tricked by my impatience.
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Old 13th June 2018, 03:00 AM   #15
rabbitz is offline rabbitz  Australia
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Glad it worked out and you have found that speaker location is very important.

Generally, tweeters should be around ear height and distances to boundaries should be different in each direction (speaker to back wall, to floor, to corner) and should not be a direct multiple of each other. Moving speakers around can find a sweet spot.

No wasted time at all but would have been a waste if the outcome was not posted.
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Old 13th June 2018, 05:08 PM   #16
jerrymchill is offline jerrymchill  United States
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@Gropascal - mate - Location, Location, Location!!! There is number of room acoustic tweaks you can do before doing crossovers exercises!!! You found it the hard way but at least you have a satisfying result. The amplifier, source and wiring will affect the sound as well. Cheers and happy listening!
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