This thread will look at pursuits related to speaker directivity and room equalization. Feel free to post your speakers of interest.
The McIntosh XRT2.1K loudspeaker standing at 7 feet, is a miniturized and improved Infinity IRS V .At 130,000 dollars it has solid theory behind it, whether or not the theory is backed up by real world performance is another matter as I have not received my review unit yet.
It offers upper mid range and high frequency directivity via 28 2" upper midrange drivers cut at 450Hz and 45 3/4" tweeters cut at 2.1kHz, these are oriented to couple in locally as TMT (tweeter midrange tweeter) and globally in a stereo setup as a compound MTM.This way the speakers deliver directly radiated upper midrange and tweeter frequencies allowing the speaker to decouple from the room, the array and a hardly noticeable hint of toe in ensures the walls are starved of the energy to sufficiently color the sound. The many drivers also ensure that each is only contributing a small amount of the overall performance, allowing the upper midrange and high frequencies to sound effortless.
The midbass or lower midrange is where most rooms have issues, McIntosh engineers cut this band at 150Hz to 450Hz making sure this speaker will perform well in most rooms, here the speaker is equalized for most rooms.There are two 6.5" midbass drivers that are physically toed in within each speaker. Locally these midbass drivers are put in a sealed section in a WMW (Woofer midbass woofer) configuration decoupling the midbasses from the room. The toe in couples globally in a stereo setup to create the global compound WMW decoupling the midbasses from the room.
The bass reflex brutes are placed towards the floor and towards the ceiling and cut at 150Hz, to give you an in room low frequency response of 12Hz, enough for goose bumps.These speakers do not need the support of a sub woofer, they are the sub woofer. There are 6 8" woofers, giving you a total of 96" in stereo setup, thats plenty of air being moved.
Based on theory alone this is a possible must have for your Beverly Hills home.
It offers upper mid range and high frequency directivity via 28 2" upper midrange drivers cut at 450Hz and 45 3/4" tweeters cut at 2.1kHz, these are oriented to couple in locally as TMT (tweeter midrange tweeter) and globally in a stereo setup as a compound MTM.This way the speakers deliver directly radiated upper midrange and tweeter frequencies allowing the speaker to decouple from the room, the array and a hardly noticeable hint of toe in ensures the walls are starved of the energy to sufficiently color the sound. The many drivers also ensure that each is only contributing a small amount of the overall performance, allowing the upper midrange and high frequencies to sound effortless.
The midbass or lower midrange is where most rooms have issues, McIntosh engineers cut this band at 150Hz to 450Hz making sure this speaker will perform well in most rooms, here the speaker is equalized for most rooms.There are two 6.5" midbass drivers that are physically toed in within each speaker. Locally these midbass drivers are put in a sealed section in a WMW (Woofer midbass woofer) configuration decoupling the midbasses from the room. The toe in couples globally in a stereo setup to create the global compound WMW decoupling the midbasses from the room.
The bass reflex brutes are placed towards the floor and towards the ceiling and cut at 150Hz, to give you an in room low frequency response of 12Hz, enough for goose bumps.These speakers do not need the support of a sub woofer, they are the sub woofer. There are 6 8" woofers, giving you a total of 96" in stereo setup, thats plenty of air being moved.
Based on theory alone this is a possible must have for your Beverly Hills home.
Look at JBL M2 or any of the Gedlee designs to see how directivity should be done. Also worth reading Earl's papers on multiple subs once the listening room goes modal. And of course the Kii3 and Beolab 90 (and its younger siblings).
All this done to death in many threads on here.
All this done to death in many threads on here.
well McIntosh don't claim that on their website . http://www.mcintoshlabs.com/us/Products/pages/ProductDetails.aspx?CatId=speakers&ProductId=XRT2.1K Not sure where the 'room decoupling' comes from.
twisted minds...
there is no acoustical benefit in toeing in (or out for that matter) of a 150<450 Hz speaker whatsoever
...except because ft the MT line obstructing on-axis and causing interferences in upper range and above xo. What type of xo?
In general I find these Steinway/Lyngdorf/McIntosh speakers strange and overdesigned and covered with heavy marketing mist. They might sound good anyway...
In general I find these Steinway/Lyngdorf/McIntosh speakers strange and overdesigned and covered with heavy marketing mist. They might sound good anyway...
What about room treatment? At that price it seems to me that room treatment would be economical.
whatever, still there is NO acoustical benefit in toeing in (or out for that matter) of a 150<450 Hz speaker whatsoever, including "decoupling" understood as You proposed, it changes nothing
Higher directivity shifts the Schroeder frequency down. Once your truly in the modal range, directivity makes room interaction just different, not necessarily better.
6 pcs 8" per side have a total cone area of roughly 1320 cm². 1 pcs 18" has roughly a cone area of 1218 cm², so it is a bit smaller area than those 6 pcs of 8" together. (A 48" dia woofer /side would mean something like 11 000 cm² per side, about 9 pcs of 18". -I have my doubts and wonder what that speaker cabinet might look like ... 😱 🙄 )
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@OnAudio:
The area of a circle is (D² x π) /4. You have 6 pcs 8” per side => stereo = 2 x 6 pcs
The ”stereo” with a total of 12 pcs 8”: 2 x 6 x (8² x π) / 4 = 603 inch².
Your ”total stereo” of 96”: 1 x (96² x π) / 4 = 7238 inch². 603 versus 7238 isn’t the same thing really, right?
(I’m disregarding we have cones here and not a flat disc or circle and also disregarding the width of the basket frame outside the cone perimeter.)
The area of a circle is (D² x π) /4. You have 6 pcs 8” per side => stereo = 2 x 6 pcs
The ”stereo” with a total of 12 pcs 8”: 2 x 6 x (8² x π) / 4 = 603 inch².
Your ”total stereo” of 96”: 1 x (96² x π) / 4 = 7238 inch². 603 versus 7238 isn’t the same thing really, right?
(I’m disregarding we have cones here and not a flat disc or circle and also disregarding the width of the basket frame outside the cone perimeter.)
I try to help graaf,
- directivity of a loudspeaker(membrane) is dictated by
- membrane dimensions
- baffle dimensions
- frequency
Here is good presentation FUNDAMENTAL LIMITATIONS OF LOUDSPEAKER DIRECTIVITY — Audio Spotlight by Holosonics
Below certain dimension, radiation is omnidirectional (4pi), sound wave bends around baffle edge without creating diffractions. Main factor here is baffle width, the distance from the center of membrane to the nearest edge.
Above that frequency directivity is constant (but with baffle step) and 2pi until wavelength gets shorter than membrane width.
Above that directivity rapidly increases (directivity index increases) which means narrower radiation angle, usually we look at -6dB limit - eg. 90¤ means 45¤ left and right.
In case of the speaker in post #2, two 6.5" drivers are in a quite narrow box, passband 150-450Hz. Only the upper end is close to 2pi limit in vertical dimension, so there is only 2-4dB decrease in sound intensity to 45¤!
The Edge is a nice way to study directivity and diffractions Home of the Edge
- directivity of a loudspeaker(membrane) is dictated by
- membrane dimensions
- baffle dimensions
- frequency
Here is good presentation FUNDAMENTAL LIMITATIONS OF LOUDSPEAKER DIRECTIVITY — Audio Spotlight by Holosonics
Below certain dimension, radiation is omnidirectional (4pi), sound wave bends around baffle edge without creating diffractions. Main factor here is baffle width, the distance from the center of membrane to the nearest edge.
Above that frequency directivity is constant (but with baffle step) and 2pi until wavelength gets shorter than membrane width.
Above that directivity rapidly increases (directivity index increases) which means narrower radiation angle, usually we look at -6dB limit - eg. 90¤ means 45¤ left and right.
In case of the speaker in post #2, two 6.5" drivers are in a quite narrow box, passband 150-450Hz. Only the upper end is close to 2pi limit in vertical dimension, so there is only 2-4dB decrease in sound intensity to 45¤!
The Edge is a nice way to study directivity and diffractions Home of the Edge
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I just can't figure out what the designer has tried to achieve with those double 6.5" lower mids. Without those the bass line would have much more directivity vertically in that ranges. And usually floor and ceiling bounce happens around 200-300Hz, even lower with long listening distance and a high ceiling...
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