Re: Gap at the front...
That should screw up any speaker that isn't specifically designed to take that into account. In particular it will decrease the effectiveness of the bass (this is similar to a trick GM suggested for reducing the bass in a box that has too much). In the right box and situations it will cause a whistle... this is probably most effective in an open or large IB kind of arrangement. Most vented boxes of any sort would be short-circuited rendering the bass loading moot.
dave
Phil Townsend said:
That should screw up any speaker that isn't specifically designed to take that into account. In particular it will decrease the effectiveness of the bass (this is similar to a trick GM suggested for reducing the bass in a box that has too much). In the right box and situations it will cause a whistle... this is probably most effective in an open or large IB kind of arrangement. Most vented boxes of any sort would be short-circuited rendering the bass loading moot.
dave
Chris and Dave,
At RMAF this year, Mr. Teramoto wrapped silk tightly around the drivers between the flange and the front baffle as a makeshift gasket. He jammed as much silk as he could in there to seal the gap.
I think this was just a temporary "stopgap" (pardon the pun) measure after the drivers were already mounted; it might be better to install a better gasket of some kind before screwing the drivers to the front baffle.
Mike
At RMAF this year, Mr. Teramoto wrapped silk tightly around the drivers between the flange and the front baffle as a makeshift gasket. He jammed as much silk as he could in there to seal the gap.
I think this was just a temporary "stopgap" (pardon the pun) measure after the drivers were already mounted; it might be better to install a better gasket of some kind before screwing the drivers to the front baffle.
Mike
Poindexter,
Here is the TS data that I have. As far as I know, this is the latest data for the D5nf drivers. (Chris, do you know if this is indeed the best data?)
It was generated using Woofer Tester 2.
Revc = 14.5706 ohms
Fs = 107.8037 Hz
Zmax = 159.5979 ohms
Qes = 0.6515
Qms = 6.4850
Qts = 0.5920
Le = 0.4430 mH (at 1 kHz)
Diam = 105.0000 mm (4.1339 in)
ConeArea = 8659.0145 mm2 (13.4215 in2)
Vas = 5.4951 L (0.1941 ft3)
BL = 7.9544 N/A
Mms = 4.1769 g
Cms = 521.8188 uM/N
Kms = 1916.3741 N/M
Rms = 0.4363 R mechanical
Here is the TS data that I have. As far as I know, this is the latest data for the D5nf drivers. (Chris, do you know if this is indeed the best data?)
It was generated using Woofer Tester 2.
Revc = 14.5706 ohms
Fs = 107.8037 Hz
Zmax = 159.5979 ohms
Qes = 0.6515
Qms = 6.4850
Qts = 0.5920
Le = 0.4430 mH (at 1 kHz)
Diam = 105.0000 mm (4.1339 in)
ConeArea = 8659.0145 mm2 (13.4215 in2)
Vas = 5.4951 L (0.1941 ft3)
BL = 7.9544 N/A
Mms = 4.1769 g
Cms = 521.8188 uM/N
Kms = 1916.3741 N/M
Rms = 0.4363 R mechanical
Poindexter said:
Chris W has a woofer tester 3 and is working thru it... taking a surprisingly long time thou. Maybe the software has one of those "invented by a tech" crossed with Windows impeniterrable UIs.
That Rick is reporting good results in Freddie Chang is maybe an indication that preliminary numbers are close to the T/S curve (or it could be that even given half a chance these drivers are so good you don't realize there is more to be extracted)
dave
The amount of time it is taking me to get a handle on Woofer Tester Pro wouldn't be surprising if you could know the circumstances under which I must work on it . . . I can only work on it at my office, and yet I can only work on it outside of the hours that I'm working on my job -- early morning and late evening (assuming I don't have to wok overtime). I'm not the least inclined to put any blame on the developers of Woofer Tester Pro. Their Woofer Tester 2 is a piece of cake to use, but Woofer Tester Pro enters an entirely different dimension of functionality. The real problem is just my own lack of time . . .
Chris
Chris
It may be easier to say than to do, but if possible I recommend trying mounting both with and without a gasket. When the washer-spacer method is used properly, you end up with a very tiny gap between the driver and the baffle, and I don't think it is enough to completely throw everything off by any means. Although it is enough to make life interesting . . . 
Well, it's a useful tuning tweak to bleed off excess pressure if you find LF tuning too heavy in a particular room, or if the driver has been mounted in a sub-optimal box. But personally, I'm not convinced that deliberately designing something with a leak-path around the driver is necessarily a good idea. I'll do it if it's specifically requested of course -we aim to give people what they want. And I'm perfectly willing to be convinced that I'm wrong. But to me a tight seal, via a gasket or whatever is going to be needed for maximum efficiency.
gasket
I've decided to use a cork gasket for mounting the D-5nf. I did some searching and wound up at the corkstore (how easy it is at times). They stock a gasket quality cork in 1mm thickness which seems perfect for the job.
http://www.corkstore.com/compass/se...yqty5=1&recid=3702887&qty=&unit=&functionid=x
Regards, KM
I've decided to use a cork gasket for mounting the D-5nf. I did some searching and wound up at the corkstore (how easy it is at times). They stock a gasket quality cork in 1mm thickness which seems perfect for the job.
http://www.corkstore.com/compass/se...yqty5=1&recid=3702887&qty=&unit=&functionid=x
Regards, KM
I used this gasket material on my Freddie and it is excellent. It is EPDM "rubber," so it will never dry out, but is extremely soft and pliable. It is only 3/8 wide so it can make the 6" radius easily. The adhesive is strong. It is hollow, so will conform to irregular surface, although can be compressed flat and gives about a 1/16"+ thickness gasket. It should be applied to the inner edge of the cutout hole, to seal the driver inside of the driver's mounting holes. Available on Amazon.com and at Home Depot stores in US. It is cheap.
Any comments on the above driver tensioning drawing? Thanks.
Rich
EDIT: I see it is broken link again. My webhost added a graphic file filter "firewall" of some kind. I wll host it somewhere else and post a link. Sorry
Any comments on the above driver tensioning drawing? Thanks.
Rich
EDIT: I see it is broken link again. My webhost added a graphic file filter "firewall" of some kind. I wll host it somewhere else and post a link. Sorry
You know what they say... the 1st 90% of the job takes the 1st 90% of the time and the last 10% takes the other 90%. I've not done much drawing (initial concepts for an aethetic sympathetic supraBaffle have gone out to the design group (no comments back from Scott... he must be either busy or stunned by what i came up with .
What i have been doing is thinking a lot about the mounting discussion, and have come up with some variations on driver mounting that will allow rear-mounting the driver with a front-gasket (removable baffle) or front mount with no hard connection to the driver, or the way i think it will work best which is everything rigid, with the driver directly coupled to the mass of all the (and inherent damping) box. To ameriolate the problems i see with no baffle connection method, i have devised an energy sink that couples to the big spike at the rearward foot. To get the most out of this is going to require a bit of machining of solid aluminum blocks, and some welding. Really hard, hardwood might work nearly as well.
dave
.What i have been doing is thinking a lot about the mounting discussion, and have come up with some variations on driver mounting that will allow rear-mounting the driver with a front-gasket (removable baffle) or front mount with no hard connection to the driver, or the way i think it will work best which is everything rigid, with the driver directly coupled to the mass of all the (and inherent damping) box. To ameriolate the problems i see with no baffle connection method, i have devised an energy sink that couples to the big spike at the rearward foot. To get the most out of this is going to require a bit of machining of solid aluminum blocks, and some welding. Really hard, hardwood might work nearly as well.
dave
planet10 said:I've not done much drawing (initial concepts for an aethetic sympathetic supraBaffle have gone out to the design group (no comments back from Scott... he must be either busy or stunned by what i came up with
Neither of the above Dave, I just haven't seen any of them. Guess the email got lost in the system somewhere.
planet10 said:
Oohh, I did the thumb-through-the-cone thing with one of an extremely rare pair of 1970s edgeless (by design) 20cm Exact drivers that I had bought used for the equivalent of about US$800.
I know it's not in the same league as a $40 million elbow through a $139 million Picasso painting, but I understood exactly how Steve Wynn must have felt.
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