Grill design

[stonemarten]

Dear experts,

I'm looking for some recommendations on a grill design. This is the speaker I'm building



what is, in your opinion, the best solution for avoid as much as possible diffraction? I was thinking to buy a plastic cylinder 10mm diameter and wrap the grill cloth around it, using magnet on the corner.
Of course if there is a kit is better

thanks to all!

cheers

[mattsk8]

Re: Grill design

I've never given any thought to baffle diffraction when I designed my grills. The only thing I do is make the frames thick enough to work (not flimsy and I usually use 1/2" MDF), try not to cover the speakers with any of the MDF grill frames, and I put a 45 degree bevel on the inside edges of the grill frame with a router. You could blind fold me and put the grill on and take it off and I couldn't tell you which it was, it sounds the same both ways to my ears.

[stonemarten]

Re: Grill design

Mattsk8,

Thanks for the infos: is there any gap between the grill and the front baffle? I mean, is the grill frame in contact with the baffle or a little bit higher?

Cheers

[jhollander]

Re: Grill design

If you use magnets there's no gap, plastic grill guides create a gap. Both work fine. Like Matt said anything around a 1/2 inch depth will create minimal changes. I still like to listen without grilles. There are grill kits at PE.

[Chris Roemer]

Re: Grill design

Arlis had a short demo on here on how he makes grills, maybe a month or two ago?

[Eternal Student]

Re: Grill design

Thread from Arlis here.
Another thread showing a very clean and easy method of attaching grill cloth here.

Hope it helps.

[mattsk8]

Re: Grill design

Mattsk8,

Thanks for the infos: is there any gap between the grill and the front baffle? I mean, is the grill frame in contact with the baffle or a little bit higher?

Cheers

I've done that both ways. I've always used magnets to hold the grilles on, and IMO it looks a little bit sharper if the grill floats about 1/4" over the baffle, plus it doesn't rub on your speaker's finish if you design the grill mounts to hold the grill over the front baffle (as opposed to against it). But that's just my opinion, and that would also depend on the design (one or 2 I've done did look better against the baffle). Sound wise I don't think it really matters if the grill mounts on or floats over the baffle, but I've never measured the differences either.

[Paul K.]

Re: Grill design

At the risk of being repetitious, I make the grille's size and shape such that some of the heads of drivers' mounting screws/bolts align with magnets on the back of the grille instead of imbedding magnets in both the baffle and grille. This usually means there's more grille members near the drivers, but since I always remove the grilles before any serious listening, I don't worry about diffraction effects from the grille. I've attached two photos showing the RS Duets and their grilles where I used 4 of the mounting screws on the RS225 woofers to attract the magnets on the backs of the grilles.
Paul

[stonemarten]

Re: Grill design

thanks a lot for all the examples!!

I think I will go to the "very clean and easy method" that Eternal Student post

cheers

[Ron Stewart]

Re: Grill design

For my Invictus, I decided against MDF frames with cloth and used perforated metal instead--simple wooden frames with a slot to hold the metal and short dowels to float the frames off the baffle.



There are details in Post #24 of my Invictus Build Thread.

Ron

[Harvylogan]

Re: Grill design

I have done grills in many forms and fashions. Some conventional and some not. One of the designs I did years ago (shown below) that got many honorable mentions was a design I actually borrowed from JBL back in the late 80s or early 90s. It involves mounting the grill on stand-offs. I am not sure if the design offers any sonic benefit, I just thought it looked nice so I did it.



Another idea that I read about (maybe on here) that sounds very interesting is one that is pretty crafty. I am going to try it on my current project. The idea is to mount the magnets in the front of the box underneath the veneer. This way, the speaker can be either displayed with or without the grill and it looks like it has been designed that way. Very cool idea. This would require 2 things. 1. magnets that have enough force to hold the grill without locational stops (not a problem for relatively small speakers) and 2. without the locational stops the grill would have to be placed on the speaker by eye.

I am gluing up the boxes this weekend. After I get some assembly and crossover work done I will post some pics of the grill after the veneer is applied if you want.

Matthew

[stonemarten]

Re: Grill design

Matthew,

yes please, I'm interested. I don't have veneer because I'm using glulam, but I don't think it matters. What type of grill design are you using? A frame like in your pics?

Ron,

like your idea as well because I have a small vandal around home my speakers are 1.3mt tall: I think that a grill like yours could vibrate a lot with the lower frequencies. Do you had any problem?

thanks

cheers

[Ron Stewart]

Re: Grill design

Ron,

like your idea as well because I have a small vandal around home my speakers are 1.3mt tall: I think that a grill like yours could vibrate a lot with the lower frequencies. Do you had any problem?

I was worried about it too before too, and had thought about injecting glue into the gap and/or sliding narrow strips of veneer in there. Because I've never heard any buzzing or rattling, I didn't do either of those things, and now I don't worry about it. The perf metal isn't perfectly flat, so it's sort of spring-tensioned in place.

Ron

[stonemarten]

Re: Grill design

thanks Ron!

[stonemarten]

Re: Grill design

Experts,

I found in a shop a wood "bar" with the profile half flat and half circular, 20mm and 10mm diameter. What do you think?
Could it reduce diffraction since there are no edges? I would mount with the flat part attached to the front baffle

cheers