Pensil 10.2 Build (Yet Another) - Page 2 - diyAudio
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Old 8th March 2013, 08:34 PM   #11
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And which (with respect) looks rather 'awkward', at least to my eyes. To each their own of course, & long may it remain so.

It's difficult to gauge the effects of the change in practice, since the lip above & the floor boundary will have some impact, but I'd anticipate Fb being raised by about 5Hz with a little more gain peaking. Theoretically this could be ameliorated by increasing the stuffing density, since I made the pensils adjustable via the damping, although going to high levels is not without its own issues. With that said, the quantities used are actually relatively modest compared to, say, some of the sealed box designs you often encounter, or some TL boxes from a few years back, so YMMV on that score. Just keep the density around / near the driver fairly modest if you do increase the overall packing to reduce the chances of it mass-loading the cone sufficiently to distort the diaphragm under dynamic load conditions. It's unlikely to damage the driver but the midband / HF will probably sound rubbish since it won't be able to resonate as designed.

Last edited by Scottmoose; 8th March 2013 at 08:46 PM.
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Old 8th March 2013, 09:36 PM   #12
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Originally Posted by planet10 View Post
With this construction you have a vent that is 0mm deep instead of the specified 18-20mm.

dave
Interesting. It did not occur to me that it is a "vent" in the traditional sense.

I had assumed it is simply a termination point, and that the height and width were the critical dimensions, whereas the "depth" was a simple function of the material used.

Click the image to open in full size.

Last edited by cogitech; 8th March 2013 at 09:46 PM.
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Old 8th March 2013, 09:39 PM   #13
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Originally Posted by Scottmoose View Post
And which (with respect) looks rather 'awkward', at least to my eyes. To each their own of course, & long may it remain so.

It's difficult to gauge the effects of the change in practice, since the lip above & the floor boundary will have some impact, but I'd anticipate Fb being raised by about 5Hz with a little more gain peaking. Theoretically this could be ameliorated by increasing the stuffing density, since I made the pensils adjustable via the damping, although going to high levels is not without its own issues. With that said, the quantities used are actually relatively modest compared to, say, some of the sealed box designs you often encounter, or some TL boxes from a few years back, so YMMV on that score. Just keep the density around / near the driver fairly modest if you do increase the overall packing to reduce the chances of it mass-loading the cone sufficiently to distort the diaphragm under dynamic load conditions. It's unlikely to damage the driver but the midband / HF will probably sound rubbish since it won't be able to resonate as designed.
Awkward looking, yes, however I did explain earlier my plan to add a grill there.

Thanks for your perspective on the possible auditory effects. Having you guys around here is amazing, as I said earlier.

Another quite simple option would be to include the missing 3 sides of the "port" in the grill frame that I plan to make. This may be difficult to imagine, but it is actually quite a simple plan. Necessity is the mother of invention. I'll figure it out, and post my solution here later.

Thanks to all who have highlighted this issue. I really did think a terminus was 2-dimensional, and that the 3rd dimension (depth) was simply determined by the material itself.

Last edited by cogitech; 8th March 2013 at 09:57 PM.
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Old 8th March 2013, 09:55 PM   #14
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Originally Posted by cogitech View Post
Mark,

I just think it is incredible to be receiving direct support and advice from the guy who actually designed the drivers I love so much! This is a unique and wonderful experience, which I appreciate very much. You have earned yet another loyal customer! What makes it even better is that the designers of all these wonderful cabinets are here in the forum, too. Incredible!

Regarding your advice; much of it I have learned from some of your knowledgeable disciples around here but, like you said, it is never a bad thing to be reminded. I suspected that large inconsistencies in the flatness of the rebates would create gaps (air leaks) so I had though of smoothing some carpenter's glue on there and letting it level itself and then cure, for a plastic-like smooth finish for the rubber gasket to seal to. I was thinking I would install the 6 screws before applying the glue, to avoid the obvious "oops". When you recommended the caulking, did you intend for me to let it cure first? Otherwise, the driver will become bonded to the baffle.
Hi C, (guys)
Glad to be of assistance. There's allot of goodwill on this section of Diyaudio, glad its developed over recent years as its helped many builders enjoy the hobby. I'm now at week 4+ out from my major surgery, gradually improving so feeling more energised to assist folks as best I can.

Re flattening the rebate with carpenter's glue sounds good, worth testing on a old piece of wood/ply prior to working it into the rebates. In the past I've used flexible bathroom sealants that don't set hard, just a thin beed run in the middle of the rebate, has worked well for me. Keeping the screw holes clear of glue is a good practical tip. I always run the screws in and out a couple times to make the threads prior to installing the driver.

Hope you keep posting as it helps other project builders, especially the newer guys.

Cheers
Mark.
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Old 8th March 2013, 10:07 PM   #15
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I am really glad that you are feeling better, Mark!

Indeed I will keep posting so others can learn from my mistakes. Hopefully I can offer solutions to my mistakes to show I am not a complete imbecile as well.
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Old 9th March 2013, 05:43 AM   #16
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Update: OH MY GOD! They sound incredible!

That's all I can manage right now!
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Old 9th March 2013, 06:18 AM   #17
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First time I ever noticed the 13-14khz content over on left back stage on the song AJA.

Resisting urge to turn up the volume is killing me!
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Old 9th March 2013, 07:11 PM   #18
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Quick question:

Can I expect the break-in period, and corresponding performance improvement, of the Alpair 10.2 to equal that which I experienced with the EL70 drivers?
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Old 9th March 2013, 11:14 PM   #19
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Originally Posted by cogitech View Post
First time I ever noticed the 13-14khz content over on left back stage on the song AJA.
Well I can remember "not" hearing it. Fortunately, I can still hear it if it's there.

jeff
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Old 10th March 2013, 12:55 AM   #20
nrg2009 is offline nrg2009  United States
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Great build. WAF seems good. How about some more photos??? Above all: enjoy the fruits of your labor.
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