My A7-500s. A journey

**gearfreak** · December 6th, 2009, 07:36 PM

So for those of us with sealed flares is it ill-advised to cut out access windows (in the motorboard) in order to get into them? (vs the trying to remove the entire thing then reinstall ?).

I recall a discussion about the 1 piece (sealed flares) being desirable for the rigidity of the single piece. In my mind, I could cut access windows in order to get to the flare interior, then re-secure a stout panel over the back of it. (maybe using tnuts, to make it accessible in the future).

I'd really like to have a look, as the flares seem just about paper thin to me, and could probably stand to have some bracing.

**Old Guy** · December 6th, 2009, 08:50 PM

Originally Posted by gearfreak

So for those of us with sealed flares is it ill-advised to cut out access windows (in the motorboard) in order to get into them? (vs the trying to remove the entire thing then reinstall ?).

I would drill a couple large holes each side then fill with mix and pour foam

- Fibre Glast Developments

Just one opinion

I have heard of people doing the same but filling with plaster or similar...but be sure to schedule a helper when standing them back up!

**Panomaniac** · December 6th, 2009, 10:52 PM

Originally Posted by Old Guy

...but be sure to schedule a helper when standing them back up!

LOL! No kidding!

Bracing and/or damping those flares is job number one. Port size is job number two. Both MUST be done. I would love to see this forum work out a good method for those who have the sealed versions. Can we figure out the actual volume behind the bass horn flares?

**Panomaniac** · December 7th, 2009, 01:38 PM

A photo of the A5s in action. Wow, it's hard to take a photo of black speakers in a dark room!
(you can see my little fuzzy "helper" there on the right)

**Russnohio** · December 7th, 2009, 08:53 PM

Cool Pano!

.....but DAMN your chair is close to those suckers!

Russ

**Old Guy** · December 7th, 2009, 10:55 PM

Originally Posted by Russnohio

.....but DAMN your chair is close to those suckers!

Great for blow drying your hair in the morning....

**Panomaniac** · December 7th, 2009, 11:33 PM

Yeah, closer than it should be. 9-10 feet. But not too bad. They do look like they'll part your hair. But they are usually well behaved.

One of these days I'll knock out a wall and turn the room the other way. Should give me about 15-20 to the speakers. Some day.

**Altec Best** · December 9th, 2009, 03:14 PM

Hi Pano, It looks like you cut the port size in half, has that helped with the bass, and is it complete, the port tuning, or do you still need to adjust further.Looking good.

**Panomaniac** · December 9th, 2009, 07:05 PM

Hey A.B. Yes, reducing the port area helps the bass. More extended, less boomy.

Not finished yet. Software simulations say that tuning the box to about 30Hz should give the best results. Well, we shall see. These things don't seem to respond like modern drivers in modern boxes. Will use three 3" I.D. pipes for ports.

I think that Bear did something similar a couple of years back and liked the results.

Stay tuned! (sorry...)

**Mustang Marvin** · December 10th, 2009, 10:30 AM

When rebuilding my A7's I called GPA and asked them for a recommendation on port size relative to the 416-8B's response I had just installed. After awhile they called me back and recommended I reduce the port size to 3.25in. X 26in. This equates to 84.5 sq. in. The bass I hear seems quite natural.

The original port size is 28in. X 7.75in. or 217 sq. in. I have also heard of reducing the port to as small as 75 sq. in. I believe it all depends on the bass driver being used and the listeners personal preference.

In any case, if you want natural sounding bass in an A7 (825/828) cabinet, the port size must be reduced. As in a thread earlier, using removable panels to reduce the port size to your particular listening style is probably the best course. However, I am satisfied with the results from my A7's.