Room deadening and CRT projectors

Gary from Spectra Engineering in Western Australia writes:

An idea for your reader Dave would be to add some acoustic deading material to his sound room. This would cut the reflections and make the Bass sound field more even throughout. For example large heavy curtains work well. I have floor to ceiling carpet in the theatre (which looks better than it sounds) and a black acoustic absorbing ceiling which really does make a big improvement in this respect. What you then get is less boomy bass and a tighter more natural sound, abet at a softer volume, like running your speakers outside in the middle of a park.

You can certainly do massive amounts of tuning of the sound with acoustic treatments. Deadening material, though, tends to have a more significant affect upon the midrange and high frequencies than the bass. I use some deadening material: foam across the full back wall — and it looks worse than it sounds!

From the amount of treatment in your room, it seems that you are enjoying ‘direct field’ sound from your speakers. That’s where the sound you are hearing is almost all directly from the speakers, with very little reflection. There’s a lot to be said for this, especially in a home theatre context. My preference is for speakers that tend to widely disperse the mid and high frequencies, particularly for stereo usage, so I have plenty of hard, but irregular surfaces in my listening space. The advantages for my way are greater ambience and stage depth with stereo. The advantages for your way are sharper between-speaker imaging, and greater detail (less smearing from time-delayed room reflections). Oh, and you ought to get a very accurate frequency response since there will be less uncertainty on how the different frequencies will be reflected within the room.

Questions:
I heard that Plasma screens have a limited lifetime, much shorter than CRT TV screens, before they start to leak or degrade. Naturally, there is not much info on this.
Can you enlighten us?

That is what I hear as well. But I believe the lifetime is still up towards ten years, so the enthusiast will likely have replaced the screen well before this is an issue. As to leaking, I’ve never heard of it being a problem with respect to actually emitting noxious substances!

Precisely how long they will last though, is not really known since the oldest consumer Plasma displays are still just around five years old.

CRT projectors, it seems they are all being replaced by the inferior but brighter DLP projector. Apart from the ludicrously expensive (>$30K+++) “handmade” CRT projectors, what is there around now that is still manufactured new and worth considering?

You know, that’s what I thought until a few months ago. But it turns out that Barco has at least one CRT model that sells in Australia for around $14,000 (ie. cheaper than the Mustang-based DLPs). I am expecting to receive one for review in the next week or two and will post my impressions when I have some.

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