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 21 
 on: Today at 04:08:00 am 
Started by Kev Parker - Last post by Kev Parker
Bill,

Thanks so much for your reply.  I should have mentioned that I'm in the UK and this is the 240v version of the unit....not sure if that makes a difference to the spec?

Thank you.

Kevin

One more quick question, I notice the original part code is d90 at the end and the link you sent has a different code.  Is that because the d90 is an OEM part code specifically for Powersoft?

Thanks

 22 
 on: Today at 03:24:52 am 
Started by Helge Dr. Bentsen - Last post by Chris Grimshaw
Thanks.

Any idea how to calculate upper frequency for a given cone diameter?
Or is one of those "it depends" questions?

It does rather depend.
For instance, metal coned drivers will usually stay as a rigid piston until a fairly high frequency, where they'll become a huge mess of bell-mode resonances and ring like crazy. An 8" metal cone might be in cone breakup (where the cone is resonating and no longer acting as a piston) around 5kHz.
Paper isn't as mechanically stiff as metal, but it does self-damp better. Many 15" subs have a breakup peak around 1kHz. An 8" might be doing that around 2kHz.
Plastic cones are another step again in that direction - even more bendy, but usually better damping. So the 8" cone might be breaking up around 1kHz, but the response will usually stay pretty smooth until the high-frequency rolloff.

We usually use paper cones in the PA world, but once the cone is treated with coatings etc, the cone resonances will decrease in frequency and Q. How much, of course, depends on the cone's material and the damping applied to it.

As an order-of-magnitude rule-of-thumb, the cone break-up resonances will usually start to occur when a half-wavelength can fit between the surround and the dustcap. They're not always in that particular bending mode, but whatever mode they are in will be of roughly similar size.

Chris

 23 
 on: Today at 02:48:59 am 
Started by Tracy Garner - Last post by Scott Holtzman
First you MUST use your full real name on these forums.

Second. Look at the photo below.  You can CLEARLY see the delays.  There are 10 hangs (not all are shown in the photo)

Those line arrays are NOT the house system.  There are NO line arrays in the house system.

That picture truly puts the scale of that room in perspective.  That is a huge space.  It makes the Q in Cleveland look like a shed.


 24 
 on: Today at 02:40:13 am 
Started by Jon Roelfs - Last post by Jean-Pierre Coetzee
This should be dual mono. If you really want to a transformer is the best way to go but also expensive for something so small.

I'd rather spend the money on another recorder with balanced inputs.

Sent from my 2014817 using Tapatalk


 25 
 on: Today at 02:36:53 am 
Started by Art Welter - Last post by Art Welter
If i had a nickel for the number of times THAT one has bit me...
We would both be so effing rich the queen would do whatever she wanted.
Test results, +/-positive...;^)

 26 
 on: Today at 02:20:52 am 
Started by Kev Parker - Last post by Kev Parker
It's an ADDA type fan.  Part Number is AD0824UB-D90(t).  Detailed specifications are: 24VDC, 0.14Amp, 4500 RPM with Max Airflow (CMM) 1.274 and (CFM) 45.019.  You can contact ADDA @ 1502 WEST YALE AVE, ORANGE, CA 92867.  Tel: 1-714-674-7920, Fax: 1-714-257-7486 for an original replacement fan...or buy one from Amazon here
https://www.amazon.com/ADDA-AD0824UB-A71GL-AXIAL-24VDC-150mA/dp/B005T56WVC

Bill

Bill,

Thanks so much for your reply.  I should have mentioned that I'm in the UK and this is the 240v version of the unit....not sure if that makes a difference to the spec?

Thank you.

Kevin

 27 
 on: Today at 02:13:44 am 
Started by Nathan Riddle - Last post by Scott Holtzman
Sorry I have not had time to comment till now.  Any masonry type structure is very weak in tension.  Also it will fail under dynamic load.  Combine those and your asking for a failure.  I love tap-cons where they are providing a pin to keep stuff from moving.  For example to keep a wood frame wall from moving on a cement slab.  For my air compressor I use wedge anchors to the floor AND straps to the wood frame wall next to it.

Something like truss in a wall is asking for trouble.  The truss will expand and contract more than the wall.  That will cause enough movement long term to turn the wall to powder.  Using a grout line to keep things strait is even worse.  It is a different material forming a stress line.  The grout line will fail sooner than the block.  Look at any crack in a cinder block wall and it almost always follows a grout line.

Tom your comments are interesting and true, I have seen cinder block basement walls fail on grout lines.  However I have to ask, we are talking about a 100 lbs or so on a structural concrete wall.  HVAC contractors hang the ductless units on the side of buildings over public sidewalks in the city without an engineering consult and these pass inspection.  Not trying to advocate irresponsibility just trying to reconcile common practices. 


 28 
 on: Today at 02:03:07 am 
Started by Nathan Riddle - Last post by Tom Bourke
Sorry I have not had time to comment till now.  Any masonry type structure is very weak in tension.  Also it will fail under dynamic load.  Combine those and your asking for a failure.  I love tap-cons where they are providing a pin to keep stuff from moving.  For example to keep a wood frame wall from moving on a cement slab.  For my air compressor I use wedge anchors to the floor AND straps to the wood frame wall next to it.

Something like truss in a wall is asking for trouble.  The truss will expand and contract more than the wall.  That will cause enough movement long term to turn the wall to powder.  Using a grout line to keep things strait is even worse.  It is a different material forming a stress line.  The grout line will fail sooner than the block.  Look at any crack in a cinder block wall and it almost always follows a grout line.

 29 
 on: Today at 01:39:01 am 
Started by Shane Crabtree - Last post by Tom Bourke
Once you fix your name per the forum rules we may be able to help.  Other needed info is what lights, controller, and if applicable light mode.

 30 
 on: Today at 01:28:40 am 
Started by Nathan Riddle - Last post by Scott Holtzman


For anything that could be subjected to extreme shear or pulling force, a safer solution is through bolts that bear on the opposite side of the wall. Then you're not depending on the tensile or shear strength of the concrete at all; it's all compressive. And concrete has excellent compressive strength.

If the other side of the wall is accessible all thread all the way through is by far the best bet.  Fender washers and a backing board to spread the load too.


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