Murphy's Corner Line Array project

[DanielT]

Today's understatement. He he.

Hypex Ncore NC250MP with your DIY speaker you will have headroom of effect so it is enough and will be over.

If you do not play loud like a maniac that is. But then you will get other problems. Cost of going to the ear doctor.

 

[ppataki]

Extremely happy to announce that the ND91-8 drivers have finally arrived!!

Posting some pictures below:

and a video using a 9V battery to make it jump a bit:

New video by Peter Pataki

photos.app.goo.gl

The next step is to order the birch plywood (will use 2x12mm and Green Glue in between)

Will keep on posting further pictures hopefully in a few weeks' time

 

[ppataki]

Hi @John L Murphy
Before I continue with my build I would like to ask you a question please:
in your original design the drivers are mounted from the back, whereas I was thinking about mounting them from the front
Are there any advantages/disadvantages of these approaches?
In my case the cabinet material will be 24mm thick so if I mount the drivers from the back there will be a 24mm tall 'wall' surrounding each driver - I am not sure if that will have any detrimental effect on their radiation pattern

EDIT: in the meantime I found this video and according to the measurements rear mounting has a detrimental effect on the top-end part:

Thank you

 

[ppataki]

A tiny update while the build is starting: I just would like to spread the knowledge about the cutout diameter for this driver if anybody wants to front-mount them (like I will)
We used a 76 mm drill hole saw (by Milwaukee) and we adjusted the final result in order for the terminal to fit in

You can see the speaker mounted:

And the hole with the adjustment in the bottom right 'corner' (it looks ugly as it was done with a knife but we will use a machine for the actual cabinets)

I am just sharing this since the official cutout diameter is way bigger and actually that would result in a far too big cutout for these drivers
I hope this is useful information for those who will come after me trying this design

 

[fluid]

Are there any advantages/disadvantages of these approaches?
In my case the cabinet material will be 24mm thick so if I mount the drivers from the back there will be a 24mm tall 'wall' surrounding each driver - I am not sure if that will have any detrimental effect on their radiation pattern

EDIT: in the meantime I found this video and according to the measurements rear mounting has a detrimental effect on the top-end part:

That is a very odd video from Ryan.

Mounting the drivers from the rear (24mm through hole) as you described is like putting them in a small tunnel. That is a bad idea you will get diffraction from the edge and a bit of cavity resonance to go with it.

Rear mounting the drivers with a small chamfer can be a very good idea. You can see in a few posts at diyaudio where I made some BEM sims of flush mounted and then a 6mm chamfer in front of the driver. The overall directivity was improved with the chamfer.

https://www.diyaudio.com/forums/full-range/242171-towers-25-driver-range-line-array-post6524791.html

 

[ppataki]

Thanks @fluid but I will stick to front-mounting this time

 

[ppataki]

Another tiny update in the meantime:

We have made a 'hammer test' with Green Glue
2x8mm plywood glued together using normal glue vs. Green Glue (7 days after application!)
I must say I could not believe it, this thing is killer!! It really works guys!!!

 

[ppataki]

Another small update: the build has started at last!!!!

 

[XpanD]

Pictures don't work for me anymore? Seems to require a Google sign-in.

 

[DanielT]

Pictures don't work for me anymore? Seems to require a Google sign-in.

Same here I unfortunately do not see pictures in post no 42.

Are there too many pictures in one and the same post perhaps? Maybe it is just you and I who can not see pictures? I'm so damn curious about this project. I long for pictures. He he.

Good luck with the DIY Murphy!

Murphy:How were the speaker elements? Did everyone work as they should?

 

[ppataki]

Only pictures in post #42 or all of them?
I will try to re-upload them accordingly

 

[XpanD]

Both #42 and #48 have the issue for me, although #42 was working when it was first posted. #44 and all the earlier pictures seem to be working fine, though.

 

[DanielT]

Both #42 and #48 have the issue for me, although #42 was working when it was first posted. #44 and all the earlier pictures seem to be working fine, though.

Exactly the same for me. Then it should be your end ppataki or probably ASR server as the fault lies.
Check with a moderator if it does not work. There was a problem posting many pictures in this thread yesterday, read from post 1026:

Topping PA5 Review (Amplifier)

I have already closed the chassis and wired. You can guess the distance from the first photo. Thanks for the pics. It's a fun thing to chew on

audiosciencereview.com

 

[ppataki]

I cannot edit those posts for some reason so I am attaching the pictures here from post #42 and #48
I hope this time it will work

and the video is here:

New video by Peter Pataki

photos.app.goo.gl

 

[abdo123]

Only pictures in post #42 or all of them?
I will try to re-upload them accordingly

do not use Google drive to share photos, just copy paste them into the forum.

 

[Ericglo]

Like others, the pics in the old posts didn't work for me.

In post #54, the pics are there as attachments. You can attach pics to your post or insert the photos into the body of your post. In the task bar above the post, you can see the smiley face for emoticon insertion. To the left, is the button to allow photos. To the right allows media.


I am really looking forward to your build. As I said in my thread, I will probably look at the BMRs but I am not married to them.

 

[DanielT]

At least now I see the pictures in post no 54.A published post is open for changes and additions X number of hours after publication (do not know how many hours) then it is locked. If you are wondering why you can not post pictures or change in previous posts. If you want to post pictures afterwards in locked posts, you can talk to the moderator.

It must have been a bit like early Christmas Eve when you got them.

5.1 mm x-max on such a small driver. It was good. It seems like you made a good choice.

 

[ppataki]

Thank you @DanielT, I fully agree!
Actually it is Christmas every day since I got them
Hopefully it will remain Christmas once done....fingers crossed!

You can see the excursion nicely on the video (I used a 9V battery)

 

[DanielT]

Thank you @DanielT, I fully agree!
Actually it is Christmas every day since I got them
Hopefully it will remain Christmas once done....fingers crossed!

You can see the excursion nicely on the video (I used a 9V battery)

Aha but have you measured each driver individually? If there is a slight difference in Ohm between, you can (without measured and examined drivers individually) in one speaker get X Ohm (totally depending on how you connect them). Same pairing second speaker Y Ohm.

So it may be. Of course, it all depends on the driver itself, how much that particular brand / model can differ from driver to driver. Measure with the multimeters, then IF it differs between drivers, you match them together so it is even Ohm between your speaker .

 

[ppataki]

Well, sorry @DanielT but I will definitely not bother with that - I will leave it to the others coming after me
The project (+some others we are doing in parallel) is taking enough time already - I will be just as happy as I can be anyway