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open baffle project

When you guys say offset do you mean offset top to bottom AND offset left to right?
BTW it never fails that I start thinking about some aspect of audio,do some research,google it don't I get led back to AK?
Two days ago...somehow I got onto the idea of what to do with the KLH 23 woofers and tweeters I have just sitting there.Now I know.
 
Top to bottom is already offset if the baffle goes to the floor. Side to side is the more important one. However, if you have small panels that do not go to the floor, then offset is needed top to bottom.

When doing the OB thing, the most important T/S paramiter is the QTS. It should be .7 or higher. BUT....I heard good OB with drivers that have a QTS of .25

See if you can find the T/S on the KLH woofer.
 
Tried out that software to the extent I could but a few things I don't know the meaning of.
What do these terms mean? edge sources,speaker source density,mic distance.
Its very interesting but of course I don't really know what the hell the graphs mean.
Seems to me a baffle measuring 35.5" square is looking good on the graph.Once I deviate from those dimensions I can't tell what the graph means.
A 10" woofer in a baffle of those dimensions offset to the golden mean of .618 is what I think I'm going to try.
What do you guys think?
I plugged in a 1219mm sq dimension and checked the graph.Does this look even better?
 
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LF cutoff will be determined by the shortest dimension of speaker to edge; just bear that in mind.

I built 1 x 8 OB line arrays of PartsExpress 269-469 speakers surprisingly similar in topology to the ones pictured earlier in this thread. They sounded interesting; comb filtering, unfortunately, is real :-P
 
mhardy6647 said:
LF cutoff will be determined by the shortest dimension of speaker to edge; just bear that in mind.
Click to expand...

Minor correction...the frequency were the LF cutoff begins will be determined by the shortest dimension. It will be a much more gradual curve if offsets (vertical and horizontal) are used so the point of audible loss of LF may be somewhat lower. With no offset the curve will be pretty steep and easily audible.
 
RayW said:
Minor correction...the frequency were the LF cutoff begins will be determined by the shortest dimension. It will be a much more gradual curve if offsets (vertical and horizontal) are used so the point of audible loss of LF may be somewhat lower. With no offset the curve will be pretty steep and easily audible.
Click to expand...

Taken as a friendly amendment :-) Thanks!
 
Also, the baffle does not have to be flat. After I built my eWave-O-rays, my friend George how helped me out with them decided to build his own pair. He only used 4 mids and a gagle of tweets. After we modeled it in The Edge, he cut the baffle in half and folded one side back. Here are pix of his OBs at my house on my "H" frames.

AK_20110129_08.jpg


AK_20110129_09.jpg


They sound really good for the little money he has in them.
 
acually, the L-shape was precisely what I used on the 1 x 8 arrays I built - mostly as a convenience, so that they'd stand up!

There is no photographic evidence of this feat... I was so disappointed by their (nearfield) sound that I dismantled them and used wide parts of the baffles (holes and all) as "flooring" up in our attic :-)

Postscript - actually as 1 x 4 arrays they werent' bad. I suspect that the 1 x 8 arrays suffered from a combination of comb filtering and my infernally clever series-parallel wiring scheme. A curved line array is probably the way to go to have any hope for near field "coherence", although AKer Beemer's Pipedream line arrays are pretty phenomenal sounding even up close.
 
acually, the L-shape was precisely what I used on the 1 x 8 arrays I built - mostly as a convenience, so that they'd stand up!

There is no photographic evidence of this feat... I was so disappointed by their (nearfield) sound that I dismantled them and used wide parts of the baffles (holes and all) as "flooring" up in our attic :-)

Postscript - actually as 1 x 4 arrays they werent' bad. I suspect that the 1 x 8 arrays suffered from a combination of comb filtering and my infernally clever series-parallel wiring scheme. A curved line array is probably the way to go to have any hope for near field "coherence", although AKer Beemer's Pipedream line arrays are pretty phenomenal sounding even up close.
 
Isn't Comb Filtering more of measurement anomaly thats cancellation effect is not readily identified by the ear/brain anyway?

RC
 
tmad40blue said:
LOL! Is that what you guys changed the sign to after we left?

...Did it lower the price any? :p:
Click to expand...

Nope, no takers. I will be listing these in bartertown soon. ALTHOUGH, I am listening to them at the moment and they sound great. Too bad they are so big....they won't work with the new life style.
 
doucanoe said:
Isn't Comb Filtering more of measurement anomaly thats cancellation effect is not readily identified by the ear/brain anyway?

RC
Click to expand...

It's a real effect, not just a measurement anomoly. Audibility depends on a lot of factors including frequencies affected (driving spacing, crossover, etc.), room effects, array size, listening distance, hearing sensitivity, etc.

I've build line arrays that had measurable comb filtering but nothing audible and I've heard some where the comb filtering was like a kick in the face (not a Chuck Norris kick obviously, or I wouldn't be here).
 
RayW said:
It's a real effect, not just a measurement anomoly. Audibility depends on a lot of factors including frequencies affected (driving spacing, crossover, etc.), room effects, array size, listening distance, hearing sensitivity, etc.

I've build line arrays that had measurable comb filtering but nothing audible and I've heard some where the comb filtering was like a kick in the face
Click to expand...


Man, with so many things to possibly make comb filtering audible, you have to wonder how did Infinity or a speaker like the Pipedreams arrays get away with it. I guess auditioning in your own environment wouldn't be just a friendly suggestion but a requirement.








RayW said:
(not a Chuck Norris kick obviously, or I wouldn't be here).
Click to expand...


Nope,that wouldn't be good :lmao:

RC
 
because you are just playing around.. why not find out what those drivers really could do. by fitting a open window with cardboard and putting the driver in the middle.. then playing them..
 
aidynphoenix said:
because you are just playing around.. why not find out what those drivers really could do. by fitting a open window with cardboard and putting the driver in the middle.. then playing them..
Click to expand...

Heck, just a solid door into another room, like the guest BR when your mother in law is over---

listening tests start at 3:15am, sharp...
 
oneinchside said:
Heck, just a solid door into another room, like the guest BR when your mother in law is over---

listening tests start at 3:15am, sharp...
Click to expand...

ROFL...
the door would require alot more cardboard.. but the mother in law might deserve it..
i guess it depends on who you want to aggravate more, neighbors or family :scratch2:
 
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