Two Vifa PL18 drivers in 45 liters box OK?

[andy2]

I have these two Vifa drivers in MTM configuration in a 45 liter box but the sound is slightly lean. So do you think the box is too big?

[vinylkid58]

Sealed of vented box? I tried 2 x P17W in WinISD sealed box and got f3 of 80Hz using 45l vol.

Jeff

[andy2]

Originally posted by vinylkid58
Sealed of vented box? I tried 2 x P17W in WinISD sealed box and got f3 of 80Hz using 45l vol.

Jeff

It is vented box. The port dimension is 3in diameter x 5in length.

[vinylkid58]

Plot shows basically whats going on. Box is 45l tuned to 40.5Hz based on your port dims. I assumed that you are using 4 ohm drivers.

Jeff

[andy2]

Originally posted by vinylkid58
Plot shows basically whats going on. Box is 45l tuned to 40.5Hz based on your port dims. I assumed that you are using 4 ohm drivers.

Jeff

Thanks. I am using 8ohm driver version. Plot shows a slight 1db dip at around the midbas region. I guess that could explain the "lean" nature of the soudn.

[vinylkid58]

Ok, here is the 8 ohm version with the same tuning. Doesn't look that bad to me. Something else going on, crossover maybe?

Jeff

[andy2]

Well, I could reduce the tweeter just a little.

Here is the pic of the speaker:
http://s47.photobucket.com/albums/f1...Anch=imgAnch10

Schematic attached.
C1 is 5.7uf; R1 is 1.75ohm

The simplest thing to try is to bring R1 to 2.0ohm / and or reduce C1 to maybe about 5uf.

[vinylkid58]

Sure, or if you can get the port out and cut off 1.25", that will do it. Nice setup BTW. I like the 2-ways with the ribbons also. Is that a PP 300B?

Jeff

[noodle_snacks]

Vinylkid, have you accounted for baffle step diffraction in your crossover design??

[vinylkid58]

Sorry Noodle, not my design. What I know about this speaker is from this thread only. The crossover schem. doesn't tell us what the tweeter is, and yes BS is another issue.

Jeff