You made may day!...Communicating with you lately has been like talking with a Jackson Pollock painting.
...
I remember Legis describing it as more of an opened synergy array... sans horn. I can picture that; vertically. Just as he states in the post you reference - https://www.diyaudio.com/forums/multi-way/357825-shadow-colossus-build-thread-13.html#post6789494
I don't see a line array.
I had a Radian 745Neo and it also had this kind of ventilation hole in the rear cup. If I remember well I had a discussion with someone at Radian that does not work there anymore but he mentioned it if to protect the diaphragm and for very small level you can close it (reversible of course). I measured the difference these days and the LF response was slightly higher by closing the hole. But take care! This is no general recommendation to close this hole. This is on your own risk!
I noticed it to! I was getting really deep on some of my recent post! lmao!!! I was thinking on one post, that "they are going to think I am crazy", I think I got poetic. GM even asked if I spoke English as a native tongue rofl!
It doesn't help that I am an artist by nature and I do have a creative way of using words, creating phrases that are not technically incorrect yet, not common to the trade.
Not exactly an insult btw (Paul Jackson Pollock was an American painter and a major figure in the abstract expressionist movement.) I can take something said and say the same thing, another way, and have the person say, "no thats not it"....Abstract reasoning is powerful. For example you can see an "opened synergy array" but not a "minimal driver line array" lol. I can see both...but I digress.
Here are some more questions I have
Anyone know how to calculate the resonance in the chamber between two isobaric loaded woofers?
If a general rule says that thd is approximately 10% at xmax why would anyone want a 1-2mm xmax?...
It doesn't help that I am an artist by nature and I do have a creative way of using words, creating phrases that are not technically incorrect yet, not common to the trade.
Not exactly an insult btw (Paul Jackson Pollock was an American painter and a major figure in the abstract expressionist movement.) I can take something said and say the same thing, another way, and have the person say, "no thats not it"....Abstract reasoning is powerful. For example you can see an "opened synergy array" but not a "minimal driver line array" lol. I can see both...but I digress.
Here are some more questions I have
Anyone know how to calculate the resonance in the chamber between two isobaric loaded woofers?
If a general rule says that thd is approximately 10% at xmax why would anyone want a 1-2mm xmax?...
Last edited:
You made may day!
I have an 8 day old email to you, unreplied....tell me more about communication issues
A lot of rambling thoughts ... hard to follow! Mostly can agree, but who knows? ...
lol I see what you did there...You are one of those not so common men I spoke of btw, and as always. Thank you.
You did....I do...and because they did....I won't......should be interpretable.
Gedlee I know you know how to figure the resonance in the chamber between isobaric woofers....is it just a standing wave and thus, SOS/dimension?
You did....I do...and because they did....I won't......should be interpretable.
Gedlee I know you know how to figure the resonance in the chamber between isobaric woofers....is it just a standing wave and thus, SOS/dimension?
Last edited:
It would be more of a cavity resonance with the volume between an assumed sphere of the same volume, and a port to the outside whose mass is the port length and area. These later two are hard to figure, but not too hard to estimate - there are standard formulas for this 3 parameter resonance.
Then sweep the system impedance and look for aberrations at about the calculated frequency. If there are none, then don't worry about it. If there are then this is a clue to where yours calcs might be off.
Then sweep the system impedance and look for aberrations at about the calculated frequency. If there are none, then don't worry about it. If there are then this is a clue to where yours calcs might be off.
Thank you. I'll probably not do anything to close the hole, but this is good information. In my home application, the driver will see very little power. I thought of the screened hole as an aperiodic load to relieve pressure.
I have an 8 day old email to you, unreplied....tell me more about communication issues
Shouldn't private matters remain private?
Another Paul Jackson Pollock painting I suppose, To clarify, "Geddes" and "they" are not the same...So, what Geddes did, I am currently doing...if he did it, it was a good idea....plus I know where he went next, bringing parts of what he "did" with him, obvious by the lack of bi-radial waveguides produced by him. What "they" did, "they" are still doing (which allows me to say "they did" vs "they do" because it is the same), that which I will not do..."They" equal the group of bi-radial users...and biradials being the thing that "I won't"......Fun with Abstraction.
I see the formula for cavity resonance, have not executed it successfully, yet, partially because no one seems to be able to show the formula along with required units lol but I'll get there....plus I think I can use horn resp as a cheat sheet if I program it a certain way
I think;
L=cm
A=cm2
V=Liters
Have two walls of the cavity moving in sync is going to play factor but maybe not in the midrange since the drivers are uncoupled? I do know that it was said that filling this cavity with Damping material helps...A lot of times when something isn't discussed much, like this topic, it may not even be a major issue...maybe
Last edited:
Its not that serious....at all. Reminds me of this guy, who on another group where I asked for someone to share measurements, joined the convo just to say that he had measurements but wasn't going to share them...He felt insulted that I asked for loudspeaker measurements......It was weird.... Actually the analogy I came up with is; To have measurements of a driver, or system, etc, and claim to not share them because of the hard work that went into achieving them.....is akin to Having a system....but refusing to not let a person listen to it....because of all the hard work it took to create the system. Thats called arrogance. Actually its the same approach made by big name manufactures. The guys that, DIYA, are basically an enemy of by educating people on the topic to the point that we, a lot of times, won't even buy their products anymore....
On the other side of the spectrum you have people like myself who had a REW file and DATS measurements (of the AXi), online in multiple areas of the internet within 24 hours of receiving my horns. I bet that information helped/educated someone. I know Joseph Crowe was very interested. Hes also been helpful to me in this endeavor as well.
Last edited:
Because it can make a great guitar speaker. Overdrive without overdriving the amp. Pick your flavor. Overdrive at 1mm and extra dirty, or, 2mm and not as dirty. For reproduction... not so good.
The concept consists - at least in my eyes - of a (low) mid-bass wavefront that 'shadows' the A-290.
Those combined woofer cabs form an almost infinite baffle. Basically a wall of low freq. sound from which the mid-highs emerge.
Somehow I'd be tempted to experiment with a first-order crossover, but that would require a large format compression driver.
In your shoes, I'd measure the space between the top of the diaphragm (dome) and rear cup Then (using hot wire) cut a round piece of 30 ppi foam that's just slightly thicker (1-2 mm) than said space and stick it onto the cup. This may significantly reduce the breakup resonances.
Attachments
Last edited: