Doc Mods

[Dr Bunsen Honeydew]

I thought I should do a Doc Mod thread for discussing principle. General Audio because it is not NVA specific.

Nothing is unique in this world, way back when Doc Mods were pretty much standard in terms of result. 1 inch marine ply cabs - the cab mods as with steel plate are to bring modern crap cabinets up to this standard. Crossover and doping - well Goodmans and others were doing it in the 1950's but I take it further to avoid all crossover components. It was the standard until the BBC bollocks became established. The only thing I think is pretty unique is removing all wadding, as I have said I think this just became a convention an automatic.

[istari_knight]

Obviously decent ply is too expensive for modern profit margins [most anyway] but why did chipboard cabinets fall out of favour with manufacturers ? IME They offer much better "sound quality" for want of a better term than their MDF equivalents.

Wadding, hmm... BAF is crap that ruins the sound, I have witnessed that for myself but what about the fibreglass in old AR's ? Is that just as bad in your experience ? The Cambridge R50's I had were full of lambswool but it didn't seem to do an awful lot... Good or bad

[Dr Bunsen Honeydew]

All wadding is bad.

MDF and HDF are in fashion now as they can be machined into "shapes" so perceived value and WAF can be created. In theory MDF should be better than chipboard but by chance its natural resonant frequency is in an area that is shown up as a tonality. Where as chipboard self damps more which in fact creates other different problems. Both benefit greatly from having steel plate added.

An interesting side thought that I have had but haven't experimented with (perhaps one of you will) is to electrically connect all the steel plate together which would turn the speaker enclosure into a Faraday Cage. Interesting to see the effects of that.

[istari_knight]

Good point, WAF is king (or Queen even) today

I know some Tannoy's have an earth binding posts next to the regular inputs which is internally connected to the bass driver basket (not sure why)... Thats different again though to what your suggesting which would completely isolate the internals from any external interference whatever they may be.

[Dr Bunsen Honeydew]

If you earth the cage it is no longer a Faraday Cage, that has to float. I had a stupid proxy argument back and forward between here and AoS about that with Pinky and others when they were trying to do their NVA BMU assassination.

[istari_knight]

If you earth the cage it is no longer a Faraday Cage, that has to float. I had a stupid proxy argument back and forward between here and AoS about that with Pinky and others when they were trying to do their NVA BMU assassination.

Interesting ! Having never constructed one I'm ignorant of the details, I assumed [the mother of all f*ck up's I know !] it would need to be earthed but a Google search has shown you're correct.