Mini Bookshelf/Desktop using 3" Fullrange

[philipreji]

Oh! Those are not subwoofers! I'm not using subwoofers. Those are the Boston Hi-Q build. There is a need for improvement in those as well, but that is another thread.

I'm using Nichicon two 220 microF 35 V caps to reach the 440 value required since a single one for 440 was not available. Could that be the problem? I read that you can do that.

Ok..I think the picture is clear now. Your driver's free air resonance is 100 Hz, but your cabinet is designed to extend the response to the lower side, down to 77 Hz. However the 440 microF capacitor connected in series to the driver will raise the resonance back to 95 Hz, and prevent the cabinet from doing its job optimally.

(connecting two caps in parallel to get twice the capacitance is not a problem in itself).

I would say, try a 1000 microF capacitor so that your cut-off comes down to 42 Hz. In high-pass configuration it is the capacitor that feeds the speaker, so it is better to increase Q by using a cap rated for higher voltage (Q=CV), say 1000 microF/63 V or 1000 microF/100 V.

What I meant is: use a cap rated for higher voltage - more than the supply voltage of the amp - so that it will not struggle to accommodate occasional transients from the amp.

 

[aashish351]

OK... strangely, I am having to contradict my own previous observations which have now changed in favour of using the HP filter. I don't know how, but after the painting job, when I put together the box again, the driver is moving a lot more on bass notes and is now actually not sounding clean at the same volume levels. The bass which was tight has actually become loose, distorted and grainy. So I connected the caps again (same 440 uF for a 90Hz cut-off) and now I prefer this. Tight, well defined upper mid bass as before (equal to earlier without-filter observation). And the added advantage of a less-grainy mid and high range sound. But, I don't understand how this has happened. I am going to do more rounds of listening with and without the filter to confirm this.

 

[philipreji]

That is interesting..looking forward to further updates!

 

[aashish351]

I still have to try the dsp xover. I will also try to source 1000 uF caps. So a few more updates coming up.

 

[aashish351]

It's been a month since the last update. I thought I should take this to conclusion.

As I mentioned in the beginning that this was a frugal build for a casual requirement, which is as the sound for my brother's gaming PC. Happy to report that it has been setup in that position and more than meets the requirement. Actually even I sometimes use that only while working on the PC. Found a decent piece of Topping TP22 from a FM. Perfect match. Otherwise the TP22 is slightly bright but puts out decent mid-fi quality bass, but with these full range mini speakers, the top end roll off compensates and actually makes the sound balanced. Attached to the integrated soundcard and with the help of foo_dsd_xover and EQ, it made it possible for me to tune the sound so easily that I don't think any more investment in passive components trials is necessary.

Only issue, the need for low bass is certainly there, especially with the gaming application. So, coming up a subwoofer diy!

I would call this diy build officially finished. Happy to provide design and assistance to anyone interested in the same build.

Total cost of this is build is 2.5K (plus 3.5K for the used TP22)... Would love to compare it with multimedia speakers in that range. But I'm sure I won't be disappointed!