Ian Savage Posted June 15, 2011 Share Posted June 15, 2011 Now, I've got a degree in this kind of thing so I should know, but I'm fairly sure my audio course never covered the two practically-related questions I've got! Fitting out an empty pair of wedge monitor cabs, and I need to know - 1/ what kind of material's good to use as the absorbant inside a cab (fully aware of the need for it to be there to prevent resonances and so on, just not sure what to use!), and 2/ is there a 'standard' size of bolt to fix LF driver into chassis? The recieving nuts are already there, and they LOOK like they're M5, but I don't want to bugger the nuts up... I've Googled away on this and found nothing, just wondering if the combined pool of BC knowledge can help me! Quote Link to comment Share on other sites More sharing options...
Balcro Posted June 15, 2011 Share Posted June 15, 2011 Hello Ian, You could try the following two links: - [url="http://www.wilmslow-audio.co.uk/damping-materials-28-c.asp"]http://www.wilmslow-audio.co.uk/damping-materials-28-c.asp[/url] [url="http://www.falconacoustics.co.uk/cabinet-parts-accessories/dedshete-wadding-acoustic-foam-gasket-ls35a-loudspeaker-cabinet.html"]http://www.falconacoustics.co.uk/cabinet-p...er-cabinet.html[/url] Quote Link to comment Share on other sites More sharing options...
icastle Posted June 16, 2011 Share Posted June 16, 2011 [quote name='Ian Savage' post='1270370' date='Jun 15 2011, 05:44 PM']2/ is there a 'standard' size of bolt to fix LF driver into chassis? The recieving nuts are already there, and they LOOK like they're M5, but I don't want to bugger the nuts up...[/quote] I'm guessing they're using T Nuts. Unfortunately they come in M4, M5, M6 and M8 sizes. Easiest way to find out would be to find an M5 bolt and try it, you should be able to screw the bolt into the rear of the T Nut using just your fingers (therefore avoiding any possibility of damage to the thread). Quote Link to comment Share on other sites More sharing options...
Ian Savage Posted June 16, 2011 Author Share Posted June 16, 2011 That's brilliant, thanks guys - 'acoustic wadding', that'll be what I need! Have to see if I can get that from a physical shop anywhere (gonna try to sort 'em out over the weekend) - cheers! Quote Link to comment Share on other sites More sharing options...
stevie Posted June 17, 2011 Share Posted June 17, 2011 If you have any old sleeping bags or duvets you don't need, take the filling out and use that. It's the same stuff. Quote Link to comment Share on other sites More sharing options...
Phil Starr Posted June 18, 2011 Share Posted June 18, 2011 (edited) Stuffing a cab is an interesting one, there are loads of theories around and you probably need to distinguish between damping the panels and stuffing the air space. On the panels it can reduce the internal reflections and mass load the panels reducing their resonance. In the air space it will affect the propagation of the sound, dampening standing waves and changing the effective volume of the cabinet, If you can get hold of a copy of the Loudspeaker Design Cookbook by Vance Dickason their are some nice measurements of the effects of differing stuffings upon the performance of cabs. One of the less well advertised effects of stuffing is that the speaker doesn't cool down so well if it is surrounded by a load of wadding/fibreglass. Edited June 18, 2011 by Phil Starr Quote Link to comment Share on other sites More sharing options...
LawrenceH Posted June 19, 2011 Share Posted June 19, 2011 Here's a link to the 'proper stuff'. I'm not sure about using duvets - I think the size of the individual fibres is supposed to determine their effectiveness. You could get lucky but when I tried some generic polyester wadding it did absolutely b****r all [url="http://cpc.farnell.com/1/1/31357-dampening-pads-mdm-3.html"]http://cpc.farnell.com/1/1/31357-dampening-pads-mdm-3.html[/url] Quote Link to comment Share on other sites More sharing options...
Phil Starr Posted June 19, 2011 Share Posted June 19, 2011 Duvets and pillows are stuffed with polyester wadding which is the same as most of that sold for speakers I use it sometimes. Mostly I use higher density materials for PA/instrument cabs, Glassfibre or Rockwool. the disadvantage is that you rally have to keep the dust out of the voice coil gap. Even the commercial wadding does 'bugger all' unless you really pack it in though it works better for hifi designs.. I don't usually stuff reflex cabs, restricting myself to just trying to prevent internal reflections off the back panel. the advantage of a wedge is that the rear panel doesn't run parallel to the speaker so the primary reflection doesn't go straight forwards back through the cone. I'm agnostic about the benefits of stuffing, people get very nerdy about it wanting the long hair wool from mountain sheep sheared on a full moon in July. Having done a lot of A/B testing of my own designs I'm not convinced it adds a lot and I miss it out except for dealing with specific resonances or standing waves. Others will disagree. Gio for whatever sounds best unless you have acces to a lot of testing equipment, Quote Link to comment Share on other sites More sharing options...
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