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I've been playing around with variations of dmv#3 for a while and have been using masking tape to assemble it between mods. Tonight I have put the screws in and I have lost something. It does not seem as vibrant. Has anyone else encountered this. Buy the way It was fairly tight and there were no gaps in the masking tape.
My current incarnation is dmv#3 with 4 holes in the felt over driver and a 16mm diameter reflector, I've tried a few things to get more bass but every time I do they lose clarity, I might try muzo2's star reflector next. How big was the hole in the felt when you tried it and what was the diameter of the star?
I got a pair of t50rp's of eBay and they arrived today. Yuk. Give me dmv#3 anyday.
Yes, I have noticed a difference when tuning with masking tape to secure the baffles to the cups compared to using the screws. IME, going from tape to screws increases the bass which may effect the perceived bass:treble "ratio." I find that I lose some treble and gain some bass when I switch from tape to screws. I don't know if this effect is due to the slight difference in the amount of compression of the dampening materials (greater compression when using the screws), better seal with the screws, or a combination of the two. It seems counter-intuitive to me because I would expect greater compression to emphasize the treble. Whatever, 5 to 10 mm compression of cotton/fiberglass is about "right" for me.
Whatever is going on, I try to compensate for this compression effect by using about 5 mm less thickness of cotton when tuning and using masking tape to hold the baffles to the cups. I always make sure I apply positive pressure against the baffle "face" and the back of the cup when applying masking tape around the rims, overlap each tape segment, and press the tape into the rim groove and then fold it over onto the rounded part of the baffle "face." I do this in an attempt to get the closest approximation to the compression when using the screws. No matter how careful I am, however, I always see some "spring" by pressing on the baffles after applying the tape all the way around the rims.
You could try removing 5 mm (just a few layers) of cotton and re-test using the screws to hold the baffles to the cups. Next, replace the 5 mm of cotton you removed and Add another 5 mm of cotton, and re-test...compare to what you heard with your initial build and after removing 5 mm of cotton. Go with the setup that sounds best.
You may also be able to compensate for the "compression effect" by altering the size/number of holes in the stiff felt and/or the size of the treble reflector. I've found that more/larger holes=more bass and larger treble reflector=more treble. Only 1 mm difference in size of the "bass boost" holes and 2 or 3 mm difference in size of the treble reflectors results in significant differences in the sound. Consider, as well, making a temporary "bass port" by applying a strip of masking tape on the outside of the cup vents. There is a guide for making a temporary bass port in Post #1 of this thread. Also, there's a guide for making a permanent bass port. Note that a "bass port" decreases bass quantity a little bit while tightening or improving bass quality.
See "Tuning Suggestions" in Post #1 of this thread after "Simplified and Consolidated DBV #3 Pictorial, located after Graph #55. Make only one tuning "tweak" at a time because each mod component interacts with all the others. The only way to assess a tuning tweak is in isolation. IME/IMO, proper preparation of the cotton and fiberglass is crucial for euphonics...see the associated guides.
Good luck and YMMV, of course.