Should I hack up 511B horns?

[SteveW]

I have a pair of 511B Horns with 808-8a drivers attached. My idea is to hack the throats up and attach 8" flex duct for HVAC feeds into my Control Room.
I have no clue - are they worth more than my idea?

[sourceoneaudio]

If you go to www.partsexpress.com you might be able to find something cheap and save you O.E.M stuff?????????? They have lots to choose from.


J/S-S1A :D

[louped garouv]

511Bs seem to hover right around $100 a pair....

FWIW

[Zilch]

Youl still need diffusers for design airflow distribution.

This is NOT a supported application, and therefore belongs in DIY.... :D

[SteveW]

Moderator, please feel free to move...
Thanks for the comments guys.

Zilch, yea their not quite real diffusers, but wasn't thinking to put any in to begin with. Was just going to bore some 8" holes in the soffit wall about 14' high, in an area that angles downward and let it rip. Thought that 'throw' would be better than diffusion because of the distance. That's when I remembered the old horns and started thinking.

....also thought you guys might have a laugh or two when I finally post some pictures of the place. :blink:

[Zilch]

Well, if it's AC, you sure don't want it blasting down.

See ACCA Manual T.

[Zilchster, HERS rater and certified energy analyst.... ;) ]

[SteveW]

Wow, Zilch is an HVAC guy too! I want to do it right so here goes. Feel bad about talking about this in Marketplace, maybe should go somewhere else. Anyway, I sure don't want to be blasted with cold air. Some background for ya.

The furnace is a 2-speed Carrier Weathermaker (Infinity) with 2-tons of AC. The room is 14,000 cu ft. and is insulated like you would expect a Control Room to be. The high-speed fan rarely comes on. In addition to the pair of 8" ducts, there is another 10" pair off the plenum that are directionally in-line with airflow from the blower. Those provide the majority of airflow and feed low into the room in proper fashion. The 8's are 90 degrees to plenum airflow so it's just static pressure. I guess the point being eluded to is that air doesn't 'blast' from the 8's. Originally, the 10's made a bit of noise so I added the 8's to slow it down a bit, but I don't have anymore real estate down low for them. The proposed outlet area points back toward the board - about 18' away.

Got a PM with a plea not to hack the horns too. Second thought time. Suggestions?

[grumpy]

As amusing (to some) and painful (to others) as it would be, I would think another
consideration would be the gain you might pick up on any noise coming through the
duct. Hacking off nearly -all- of the horn might take care of that & you'd be mostly left
with a diffuser... works for me ;). I'd rather see decent/usable horns go to a good home
and broken ones further hacked up... It's not like they're hard to find in poor condition
:)

-grumpy

[Zilch]

There's a substantial rectangular section in the horns. Use a perimeter fitting (boot), PH-1, 2, or 3, as appropriate, to make the transition from round flex duct to rectangular section. Manipulate the cross-sectional area and flow rate for "quiet."

I'm just suggesting that, operationally, shooting out the face of the soffit would appear to be a better choice than downward.

I don't think anybody really understands how airflow distributes in a plenum; once it's pressurized, all bets are off. It just works. Only high-end engineered designs use vanes in there anymore.

Flex duct itself will mitigate some of the noise. Your right-angle takeoff is working in your favor for that, as well. Straight-line to the fan is the worst, of course. Bends are good if you can take the friction losses....

[SteveW]

Till now I was thinking to just insert the horn in the duct (insulated flex) and shape the duct around the rectangular section. Then mark the spot and cut, leaving a bit of flange and tape it up. A boot or an adapter from 8" to rectangular (from Home depot) would let me mechanically attach to the horn - good idea. The horns are in not that good of shape - not broken, just need a paint job.

[Zilch]

Well, they're sure gonna LOOK cool!

[We'll want pics, of course.... :p ]

[SteveW]

A cloud of apprehension is looming over here.

One way or the other I have some drivers for sale. Have to see if they work now! Thanks again all.

[Zilch]

Hee, hee.

I was wondering where the Mods were gonna stash this thread.... :p