'LGT' Construction Diary

[sq225917]

bitumen pads are good for damping resonance on the speaker wall but you need BAF or similar on top.

they do next to nothing unless you put them on in a full sheet, ie one per internal wall, small sctions and offcuts dont do the job the same way.

i used offcuts from3 big sheets of dynamat for my CD player casing, the effect was subtle.

weeks later i ripped it out and replaced it with single sheet per surface, cut to fit and it effect was huge in comparasson. tested with stethoscope on outer of casework.

i was thinking of buying an accelerometer, the GF'S father has an an anaologue Ocilloscope i could have to hook up with.

mihgt you be interested?

[Salas]

A thing that worked wonders for thick MDF was when I placed (using benzine glue and 5 screws) ceramic floor tiles over thin rubber mat against cabinet walls.

[ShinOBIWAN]

Things seem to have slowed right down but have had a cold that put me on my backside for a few days. Hopefully the pace picks up.

I'm now working through the changes I made to the design which brings it from this:



To this:








Looks a bit weird in those shots as the baffles don't match up with enclosures (see the big overhang at the top). That will come together later once I redo the tweeter baffle and add the extra layers to the existing bass cabinets.

Canceled the Deflex order and went with 3mm thick lead flashing which I'll be applying with contact adhesive and precision hammering . I bought an 8m x 15cm roll and my god is this stuff heavy - perfect for damping. Cheaper than the deflex by far too.

On top of the lead flashing I'll apply 2mm bitumen with a 10mm foam top layer. Then a light fill of BAF wadding in the bass section and the formed open cell foam I showed a couple of pages ago, in the mid section.

Also need to route the internal speaker cable before sealing the cabinet up so did the usual ebay hunt and bought a few meters of QED XT400. I never really noticed much difference between speaker cables and I think any differences I do hear are the ones I make myself rather than the cable's influence So the QED is middle ground for me.

[edjosh23]

Shin,

I like the new look. Very nice. I'm waiting for more pictures.

Josh

[ShinOBIWAN]

Originally posted by edjosh23
Shin,

I like the new look. Very nice. I'm waiting for more pictures.

Josh

Thanks. I think I prefer the original but this one physically time aligns the mids and tweeter at a specificied listening distance on the tweeter axis. The original didn't as I thought the cabinet construction would be too complicated at the time.

[FullThrottleRic]

Originally posted by ShinOBIWAN


Thanks. I think I prefer the original but this one physically time aligns the mids and tweeter at a specificied listening distance on the tweeter axis. The original didn't as I thought the cabinet construction would be too complicated at the time.

I like the new bendy enclosures

[sq225917]

so is the listening distance about 3.5metres?

[ShinOBIWAN]

Originally posted by sq225917
so is the listening distance about 3.5metres?

Ideally 2.75m from the tweeter to your ears, with a nearfield listening ratio that would put the speakers at about 2.5m apart.

[Norman Tracy]

The Man wrote:

"Canceled the Deflex order and went with 3mm thick lead flashing which I'll be applying with contact adhesive and precision hammering."

As an electrical engineer who deals with the effects of the EU's ban on lead every day it is with no small sense of irony I learn via this thread that in the UK one can still buy the dread metal over the counter by the sheet!?!? Not to worry, when the Green Police come and take you away we will run a fund raiser on diyAudio.com to make your bail and hire the best solicitors money can buy! Of course our first priority will be to bail the speakers out of the evidence lockup from whence they will be spirited underground to a series of undisclosed listening rooms, oh I mean safe houses; for our listening pleasures, no I mean their protection of course. Our very next high priority (after the solicitors’ fees are paid) will be to bail out the builder.

Seriously now, I can only add to the choruses of ‘WOWs’. I like the way you design with many versions in CAD but are not afraid to tweak the design once it beings to appear in the real space.

[Tenson]

I think the 'lead' is not actually lead, it is something else very similar and very heavy, they just call it lead flashing. I may be wrong though.

Shin, I carried a 3m roll just over 1 mile to get it home recently! Yes, its damn heavy. And I'm a skinny wimp! Its quite funny at the check-out though when they try to pick it up and move it to the scanner and bag it Poor lady - 'Do you want help packing?' Me - 'Maybe its best I do this one?'.