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February 5, 2010 / consort3

Tweaking the DAP D3109

A pair of these were on special offer for £15 from CPC.  It is intended as a stage monitor with a wedge shape and black felt covered cabinets. The sides are robustly built with relatively thick MDF.  They could be the basis for computer monitor speakers. Since they are roughly the size of the LS3/5 and have a 5.25in driver I will experiment to see how good they are.

I thought I would test them before tearing them apart. First listening impressions are quite good with no obvious flaws, however after a time fatigue sets in.  The woofer is quite good with a reasonably smooth response to 3KHz then some jagged breakup modes. The tweeter is poor with some peaky breakup modes at 9Kand 11k, leading to the fatigue I guess.  The crossover is one capacitor on the tweeter.

I had previously found that the £5 Maplin tweeter L65Aw was not bad and it fits the tweeter space in the cabinet. I had to cut slots for the tweeter terminals and ease the diameter both of which I did with a medium coarse file. I thought I would develop a passive crossover for this combination.

Using the DCX2496, I found I needed a 3rd order Butterworth low pass filter at 3Khz for the woofer and a 3rd order Butterworth  high pass filter at 3.24K for the tweeter. Those filters give a clean out of band response and a good reverse null, indicating that the drivers are in phase at the crossover frequency

Using components sourced from Rapid electronics/CPC/Europe-audio the crossover can be built for a reasonable price. 

C1 is 2 off 4.7uF in parallel as is C2 and C5. C3 is a 2.2uF in parallel with 2 off 1uF. C4 is 2 off 4.7uF in parallel with a 2.2uF The tweeter is wired in phase with the woofer. It is best to mount the components in a box outside the cabinet. This box can be used to cover the terminal panel hole and decent binding posts mounted on the box.

The listening tests with a passive crossover were impressive enough to use these as the rear speakers in a surround set-up.

Update. Spotted these on German websites as the McVoice 2V-130 but the woofer looks to have different cone material. Talking of German websites I found this project:

http://www.diy-hifi-forum.eu/forum/showthread.php?t=4009

I think for British users the project should be re-named but I reckon the Maplin tweeter referred to above would suit this.

Another budget project, more the LS3/5 size (I use quadrant for baffle rounding but this appears to  use skirting board!):

http://www.diy-hifi-forum.eu/forum/showthread.php?t=4847

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