The long wall test

[OldiesButGoodies]

Thanks Adam - good input.  I am looking to replace three of four Ikea chairs with one big leather sofa that will hopefully have some of that "bass trap" feel (if anyone is interested in the chairs/ottomans let me know, we may be able to work something out).

I ended up testing a different arrangement along the original wall.  I moved the home theater left/right speakers closer together next to the flat screen,  and replaced the 120" front-projection screen with a smaller 100" acoustically-transparent screen that drops in front of the Polks. So the Carvers can be closer together as they need to be for the proper 2/3 rule effect and away from the back wall.  Sounds very nice.  I should post pictures when done. 

Also upgrading the Amazings with 8 new 12" woofers from Dynavox and rewiring them one more time in the process.  Hoping the break-in period is short. 

[Sir Thrift-a-Lot]

Leather will help somewhat, because of braking up the waves, but cloth is much better for absorbing sound.   The shiny surface of Leather is nearly as reflective as paint.   If you want a compromise, perhaps suede would be a better way to go.

[AdamG]

Also upgrading the Amazings with 8 new 12" woofers from Dynavox and rewiring them one more time in the process.  Hoping the break-in period is short.

I'm guessing you've matched the QTS and everything? Those floppy motors on the originals are designed for that speaker system from what I read. I don't know if you'll really be upgrading or side-grading. I know you're using active EQ which makes life much easier, as you can be less critical of the woofer's sensitivity and such, but you'd probably want to keep an eye on that as well.

Modern open-baffle design calls for a woofer with a QTS of approximately .7, it would require a bit less equalization in the midbass/bass regions. The motors are strong enough that they don't need the backpressure from the box to help the cone movement. A qts of .707 is what you shoot for in a sealed box, so without the box that's the woofer strength you'd need.

Definitely keep the originals for if/when you decide to sell off the amazings.


Example of a 12" driver with a qts of ~.7: http://www.parts-express.com/goldwood-gw-1244-12-butyl-surround-woofer-4-ohm--290-366


If you want to see what an approximate response would be, you can enter the parameters into one of those subwoofer box calculators, (or google the program unibox and use that) and select 'sealed box' and set the box volume to like 50-100 cubic feet. It's replicates open-baffle.

[Reverend]

The new drivers are OEM replacements.  The specs are the same as the originals.  Up until about a year ago, you could not buy replacement surrounds, but Dynavox still manufactured the woofers.

[AdamG]

The new drivers are OEM replacements.  The specs are the same as the originals.  Up until about a year ago, you could not buy replacement surrounds, but Dynavox still manufactured the woofers.

Oh! Well that makes life much easier now doesn't it!

[schwarcw]

Good job Pepe!  I am very interested in your results, and some pictures!