"The bigger issue is the need for a non-axi-symmetric waveguide. MTM doesn't work with a round waveguide"
Why, if "you don't consider vertical response to be a critical issue?
"Two 8" drivers would not have the low end that I'd look for in a good main speaker."
All that's needed is 80 - 100 Hz, right? I though subs were assumed.
Why, if "you don't consider vertical response to be a critical issue?
"Two 8" drivers would not have the low end that I'd look for in a good main speaker."
All that's needed is 80 - 100 Hz, right? I though subs were assumed.
noah katz said:
Are you trying to twist my words around? Vertical is not "critical" but if it can be improved while maintianing an excellent horizontal then its worth looking at. MTM with a round waveguide would not be CD. MTM with an elliptical could be.
I like the mains to overlap the subs and I don't like the subs going any higher up in frequency than necessary. 8" aren't ideal in this regard.
You are looking at things as black and white but they are grey.
According to well known theory a MTM needs very small drivers and low xo point
The low xo point is possible here
But best drivers would be a size 4" or so, which is very far from 8-10"
Fore PA or disco it may work, but fore finer hifi probably too flawed
If very high SPL have highest priority, then WTW may have some advantage, and its flaws of lesser importance
Still, I would expect a 2.5way WWT to be better
The low xo point is possible here
But best drivers would be a size 4" or so, which is very far from 8-10"
Fore PA or disco it may work, but fore finer hifi probably too flawed
If very high SPL have highest priority, then WTW may have some advantage, and its flaws of lesser importance
Still, I would expect a 2.5way WWT to be better
Just a small remark that popped up in my mind
A very great number of commercial speakers are designed in many ways that often goes against whats often said in here, over and over again
So why can they do it, and we cant, and why does it work fore them when people in here say it cant work
Well in short, theres no need to repeat other peoples mistakes
And the united knowledge in here and whats avaiable of other speaker enthusiats homesites is so incredibly huge that it at times is really hard to keep up with, maybe even fore many pro designers
A very great number of commercial speakers are designed in many ways that often goes against whats often said in here, over and over again
So why can they do it, and we cant, and why does it work fore them when people in here say it cant work
Well in short, theres no need to repeat other peoples mistakes
And the united knowledge in here and whats avaiable of other speaker enthusiats homesites is so incredibly huge that it at times is really hard to keep up with, maybe even fore many pro designers
markus76 said:
Obviously I used the usual non understandable irony...sort of
something I usually avoid, because its too easily misunderstood
What I meant was that many people look at commercial speakers, and say "I want that"...and its really hard fore them to understand when people here say "DONT DO THAT" ...especially when its done in "highend"...the stuff that make people dream
gedlee said:
You might get a kick out of my new listening room. I've put five subwoofers in the floor, and I'm treating the ceiling above the listening position.
There will be a total of eight subwoofers when I'm finished:
Five sealed subs in the floor
a tapped horn and two bandpass mounted above the ceiling
So a total of eight subs, in two vertical planes.
ok so I got another quote on the foam and it gets closer to what you are getting:
a) water filtering foam - Polinazell - blue color
16x16x8" ... 18 USD
36x18x18"... approx 100USD
b) air filtering foam - Regicell - black color (same dimensions)
400*400*200 mm ... 29USD
900*450*450 mm ... 160USD
a) water filtering foam - Polinazell - blue color
16x16x8" ... 18 USD
36x18x18"... approx 100USD
b) air filtering foam - Regicell - black color (same dimensions)
400*400*200 mm ... 29USD
900*450*450 mm ... 160USD
Earl, since you have worked with acoustic simulation of rooms; how useful will a 2D simulation of a room be? I ask because I consider implementing Stephen Kirkups 2D BEM code for room simulation, to see the effects of source placement etc. So will a 2D simulation, using the floor plan of the room, give any useful information on room modes, the response in the listening position etc?
Thanks,
Bjørn
Thanks,
Bjørn
Bjorn
It will work as well as any room simulation. I not a big fan of room simulations because they don't tell you much, unless the room doesn't exist. There are ways, such as in my thesis, to add the third dimension analytically which only requires that you assume the floor and ceiling are parallel, which is a very good bet, but not always true. The vertical dimension then uncouples from the other two. But the floor plan can not change from floor to ceiling so you can't model things like consols etc. But you can't do that in 2-D anyways. A 2-D model of a room with no parrallel surfaces would not be any good and major room feature, like consols, also prent a problem as they dramatically change the room modes and require a full 3-D analysis.
BEM can do 3-D of course!
It will work as well as any room simulation. I not a big fan of room simulations because they don't tell you much, unless the room doesn't exist. There are ways, such as in my thesis, to add the third dimension analytically which only requires that you assume the floor and ceiling are parallel, which is a very good bet, but not always true. The vertical dimension then uncouples from the other two. But the floor plan can not change from floor to ceiling so you can't model things like consols etc. But you can't do that in 2-D anyways. A 2-D model of a room with no parrallel surfaces would not be any good and major room feature, like consols, also prent a problem as they dramatically change the room modes and require a full 3-D analysis.
BEM can do 3-D of course!
gedlee said:
Hi,
I only just noticed this so I hope you'll forgive my very late reply!
This is not quite correct and is a rather dangerous assumption - the definition of 'darn near' notwithstanding!
For example, at 2k (right in the heart of the greatest sensitivity of human hearing), at only 110dB SPL the average studio condenser mic might have IM products around -40dB below (or 1%) - this I measured in a 414 (with pad).
At 130dB (eg drumkit or orchestral peak) we can expect this to rise to -20dB (10% distortion!) or worse.
Ignoring the actual audibility of the products involved, we must still take account of the mechanism of the non-linearity - the average mic is quite a compressor!
IF we could put the backplate of the microphone infinitely far from the diaphragm, there would be infintely insignificant non-linearities, but we would also have infinitely low output and noise would be an, err, infinite problem.
However, given a constant backplate distance, reduction in non-linearity is proportional to increase in acoustic impedance (this principle I apply in my 'horn-loaded' microphones).
Did you ever measure difference-frequency distortion for your earthworks mic?
The published specs for most microphones only include the distortion of the electronics, and given that the capsule introduces far more distortion than the electronics, these measurements are misleading.
In any case, I know of no recording microphones available that are able to approach the <-90dB (~0.003%) distortion @2k@110dBSPL which I measure with my impedance matching microphone.
Best regards,
Andy (Simpson Microphones)
