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Amp to make Dayton's happy (Read 28904 times)
DirtDawg
Ex Member



Re: Amp to make Dayton's happy
Reply #75 - 01/25/06 at 19:34:01
 
I guess it depends on how you built it. I've seen some pics where the whole side was removable, others had a removable panel in the center chamber, and some made both ends removable. My next one I plan to make one side removable to make access to everything easier.

I've only built one and the ends were removable and I simply dropped the drivers in from the top and bottom. I used black sticky drain pipe putty as a gasket, which is available at Home Depot - a few bucks for a huge roll. It makes a fairly permanent installation, but you can pry the driver lose if you need to. A similar product that is white and made for windows is also good. BTW I had the baffles loaded with "T" Nuts before I glued them in place.
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Bob
Ex Member



Re: Amp to make Dayton's happy
Reply #76 - 01/25/06 at 20:12:08
 
Not a bad idea about the putty. In the automotive industry we use a material we call 'dum dum'. It's about 1/4" - 3/8" diameter 'rope' that comes in a roll. Black and gooey used to seal HVAC in cars. I think our parts department has some.   ???

I'm thinking I'll make one entire side removeable to ease in driver musical chairs. Will probably design some overbuilt PITA as a gasket. Thought about a 48" piano hinge to make almost a closet door type setup. You've seen the pins racecars have to hold the hoods on, that would be the latch. Would require extensive gasketing, almost like a refrigerator. Somehow keep gasket in place during use.  No, .... I won't call fridgedaire and ask the spl rating of the fridge gasket.  ::)

Bob
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DirtDawg
Ex Member



Re: Amp to make Dayton's happy
Reply #77 - 01/25/06 at 20:23:24
 
I'll bet "dum-dum" is the same stuff the plumbers use. Since you are in the auto industry and want a bad news gasket ..... think about what they use for pick up toppers as a gasket. It has glue on one side, too.
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Bob
Ex Member



Re: Amp to make Dayton's happy
Reply #78 - 01/25/06 at 21:45:25
 
Yea, "Camper tape". much easier to work with.
Bob
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Sean
Ex Member



Re: Amp to make Dayton's happy
Reply #79 - 01/25/06 at 22:19:06
 
I would forget the door idea and stick to lids top and bottom.  This cabinet needs to be as stiff as possible, and I can't really see an advantage of having a hinged door on something which is likely not to be opened with any sort of frequency.  Drivers mount to the upper face of the top baffle and the lower face of the bottom baffle, through the ends.  I used T-nuts for this.
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DirtDawg
Ex Member



Re: Amp to make Dayton's happy
Reply #80 - 01/25/06 at 22:49:24
 
Of course, Sean is right, but I was thinking we had gone past reality and were engaged in thought play at this point. At least that's what I got from your hinge idea.

If you're worried that it will take a long time to decide which "tuning" you prefer, don't. You have 2 drivers, right? You also have 2 ports and 2 chambers, the center one doesn't make sound so it doesn't count.

Placing them with the magnets in the center chamber will give you the lowest tuning in both ports.

Placing them with the magnets in the vented chambers will give you the highest tuning in both ports

Both of those arrangements will give you a push-pull loading with the drivers firing in opposite directions and result in the least non-linearity distortion. Either way I would wire them electrically out of phase with each other so that they work in unison...... both helping each other.

You can also place the drivers with both magnets down, push-pull. This will give you the lowest tuning on the low port and the highest tuning on the high port. In other words the widest bandwidth box.

Reversing them and placing both magnets up gives you the narrowest bandwidth.

I prefer the lowest overall tuning.
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Bob
Ex Member



Re: Amp to make Dayton's happy
Reply #81 - 01/26/06 at 12:13:44
 
K.I.S.S. (Keep It Simple Stupid)

Ok, Ok, I got a little crazy there, sorry. One of my faults is that I'll over analyze something to death. Can't even build a freakin' box without over-engineering. Should have been born a Porsche, or BMW engineer.

Seal all four sides so the center chamber will never be accessible. Mount the drivers in the ends, Leave end caps removable, and do any moving around from the ends.

Yes DD, I do have 2 drivers. Thinking the magnets will both end up in center chamber. My (6) surrounds have a range from 65hz to 21khz (Niles OS-10's). All currently set to large since no sub yet. So I havn't played with built in crossover settings on the receiver much (Harman Kardon AVR 525). They don't have much 'punch' left that low in hz, so some tweeking will be needed with crossover setting, and driver placement. Will purchace some form of calibration device to assist. Still havn't done anything with room acustics so will have to recalibrate once that's done. Slow process. Money, time, and knowledge making it that way. Mainly money.....

Bob


For some reason I can only post at work. At home this web site will let me log in, and acknowledge me at the top of the screen. If I click on anything it will direct me there, but top of screen says I'm a guest again. Will NOT keep me logged in. Hmmm. So no posts this weekend.  

I will try to have pics on Monday morning pending development of photos.

Bob
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DirtDawg
Ex Member



Re: Amp to make Dayton's happy
Reply #82 - 01/26/06 at 12:34:12
 
Try Tools / Internet Options / "delete temporary files" (delete all offline content)...... "delete cookies". You might make sure your browser checks for newer versons of stored pages under settings, also. That stuff becomes corrupt sometimes if you use Windows.

The only caution is for other sites you visit that log you in automatically using cookies. You will have to log in to everything again.

I have found that this site dumps you off at odd times or when you least expect it, especially if you refresh a page it many times logs you off as part of the command. Security reasons, I guess.
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Bob
Ex Member



Re: Amp to make Dayton's happy
Reply #83 - 01/26/06 at 13:08:20
 
Yea, using windows, havn't tried deleting cookies. I did lower my security settings to allow all cookies (Hello virus, come on in) that made no difference. Having no problem at work, only home. Totally unable to post at home. Fairly annoying. Actually have more internet time at work then at home. If I'm at home I'm building / tweeking / destroying something. Work is in slow season, and boss is very tolorant of play time  ;D.

Bob

p.s.  Love your signature DD.  Know just how you feel.
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« Last Edit: 01/26/06 at 13:10:06 by Bob »  
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Adrian D.
Ex Member



Re: Amp to make Dayton's happy
Reply #84 - 01/26/06 at 19:04:34
 
now about the magnets in center chamber : there would be another advantage besides lower tuning. the cones will couple together better and improve linearity because it's sort of an isobaric loading
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J_Rock
Ex Member



Re: Amp to make Dayton's happy
Reply #85 - 01/26/06 at 20:55:38
 
if you decide tyo keep the magnets in center chamber, hot glueing a dowel of correct lengths to the rear of each driver will keep the baskets coupled even more.  This makes a huge effect in dipole full range cabnets I have done.  Perhaps it would benefit a HWK.
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Bob
Ex Member



Re: Amp to make Dayton's happy
Reply #86 - 01/26/06 at 21:17:09
 
"ISOBARIC LOADING" is a term I've heard many times, not very sure of the meaning.

Dowel rod sounds like a very good idea, but the Daytons I have, have a hole in the center covered with a screen. Don't know how I'd attach the rod.

Bob
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DirtDawg
Ex Member



Re: Amp to make Dayton's happy
Reply #87 - 01/26/06 at 23:26:41
 
Good suggestion J_ROCK!

I used to cram/jam/brace the magnets in my folded horns against the backs of the cabinets and it cleaned up lots of harmonic mishappenings. Making the entire supporting mass one unit really helped in such a high pressure area. Any time you make a cabinet more solid it is a good thing.

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DirtDawg
Ex Member



Re: Amp to make Dayton's happy
Reply #88 - 01/27/06 at 00:11:06
 
That funny hole is necessary for cooling the voice coil. Don't block it! You could still have the same bracing by using a flat board with a "U" shape cut out of the ends. Make the U bigger than the hole and it won't impede the airflow.

"Isobaric" refers to pressure or more precisely, equal pressure. When you put 2 drivers together and make them work as one, the pressure between them remains equal on one side of the motor and aided by the other motor and cone, gain a little bit a stability from the "loading". Two motors working as one, coupled with an equal(izing) pressure chamber in between is stronger than one motor.

Many people will say it's a waste of a good driver and that one driver alone will be just as good. They would be correct as far as the first half, or so, of the drivers operating capability goes.

It's when you really need to lean on the drivers that the benefit from iso-loading becomes apparent. When really pushed, the double motors are more stable and resist over-excursion better than one single driver alone can.

In addition to all that, when you have them facing each other and they work as one unit, any non-linear distortion will be averaged and theoretically reduced to one half. Non-linearity is caused from a driver moving in one direction with a different compliance, or restance to movement, than it moves in the other direction. If it moves out easier than it moves in, or vice versa, you have a problem ...... a very common problem.
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60ndown
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Re: Amp to make Dayton's happy
Reply #89 - 01/27/06 at 14:24:06
 
[quote author=DirtDawg  link=1137542099/75#88 date=1138320666] any non-linear distortion will be averaged and theoretically reduced to one half. Non-linearity is caused from a driver moving in one direction with a different compliance, or restance to movement, than it moves in the other direction. If it moves out easier than it moves in, or vice versa, you have a problem ...... a very common problem. [/quote]

interesting, i have wondered when people talk about inverting subs, it seems to me the front of a woofer would move more air than the back? people have argued and said it doesnt make a difference, but i cant get my head around the different shape reacting differently with air? flat subs would seem to overcome any differences eh?
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