The three baffles are displaced 5mm at most front to back from each other.
That maybe the case. SPL from vibrating panels (plus the SPL from diffraction).
i.e. voicing
George
5mm from a midrange to a tweeter, not a woofer to a tweeter. Also it may have been a phase thing. The whole time alignment for impulse has yet to be proven to me as a valuable attribute beyond regular old wavelength distance rules for drivers. However I have zero doubt that there can be other great reasons to distance drivers back and forward.
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It was one of the first time -aligned efforts.
-RM
Diffraction off the edges depends on the distance to the edge and wavelength being reproduced. Narrow width enclosures do better.... but the tweeter will always need rounded edges or felt due to its short wavelengths... or an open/no baffle.
Non-linearity in horn throats etal have been investigated for many years. take a look at the design of the compression driver used in JBL M2 to reduce distortion.
It is very easy to get high SPL reading with low power if measured very close to driver. It is the power needed to fill a large room at distances far from driver that is the real number to use for distortion from driver.
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The delay may not be as long as in physical driver displacements and thus be either too short in any case or not representing the real physical conditions we listen to. No conclusions can be drawn.
Forget the maths for estimating and predicting as they often are limited to simple and/or idealized conditions anyway. just measure it; That gives accurate and realistic data for what you have.
THx-RNMarsh
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Note also that near-field listening has side benefits besides the major one of eliminating room influences on the sound; The power level needed for a given SPL is very much lower and thus the driver operating in more linear displacement range.... lower driver distortion produced.
Over-all result - greater accuracy.
THx-RNmarsh
Over-all result - greater accuracy.
THx-RNmarsh
Newbie thoughts.
Diffraction :
If upper mid range or tweeter needs to eliminate diffraction by rounding of or soft pads; a coaxial would not be a good choice for sound reproduction. Has any Big Ticket Vintage Coaxial or modern coaxial solved this problem? it would be interesting to know the design. Ideal would be to have a tweeter in coaxial little ahead of the cone. Isn't it ? I remember seeing some vintage coaxial where tweeters were fixed ahead by two metal strips on the basket. Forgot the name. Two separate drivers solves all this problems.
here is an article by Jon Dahlquist. Link
Regards
Diffraction :
If upper mid range or tweeter needs to eliminate diffraction by rounding of or soft pads; a coaxial would not be a good choice for sound reproduction. Has any Big Ticket Vintage Coaxial or modern coaxial solved this problem? it would be interesting to know the design. Ideal would be to have a tweeter in coaxial little ahead of the cone. Isn't it ? I remember seeing some vintage coaxial where tweeters were fixed ahead by two metal strips on the basket. Forgot the name. Two separate drivers solves all this problems.
here is an article by Jon Dahlquist. Link
Regards
Very good article regarding what is wrong with many speaker/room issues for the times. He tries to get more directionality thru dipoles. Today we have waveguides (not horns) that control directivity very much better over a wide freq range. The work by Geddes and others is in that direction for greater accuracy thru lowered room affects.
Never-the-Less, at that time few if any near field monitors had been thought of for home use. I too had used dipoles (Quads) until recently. Today, the better near field monitors also use waveguides and sophisticated DSP cross-overs. And include all the ancient times solutions that still work... smooth rounded edges/cabinets for one.
THx-RNMarsh
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That article contains much information that is often either overlooked or misunderstood.
In the room where I use my DQ-10s there are effectively six Helmholtz resonators and eight diaphragmatic ones. The room dimensions are not effectively integer multiples. Then there is a similar coupled space.
Thus the room is designed to add some color to the reproduction.
Now how many have experienced the wow factor in a recording studio versus a concert hall?
I seem to find many recordings benefit from a bit of sweetening.
In the room where I use my DQ-10s there are effectively six Helmholtz resonators and eight diaphragmatic ones. The room dimensions are not effectively integer multiples. Then there is a similar coupled space.
Thus the room is designed to add some color to the reproduction.
Now how many have experienced the wow factor in a recording studio versus a concert hall?
I seem to find many recordings benefit from a bit of sweetening.
The narrower and Constant Directivity speakers are the best solution to date...… actually known for decades... before the Dalquest art. All have been trying to do what we can better do today with the newer CD speaker designs.
Isn't it time we move our discussions into the 21st century designs? Kinda reminds me of still talking about TT and phono cartridges for ever. More accurate ways exist today. Lets work to understand todays technologies and how to improve them where possible.
THx-RNMarsh
Isn't it time we move our discussions into the 21st century designs? Kinda reminds me of still talking about TT and phono cartridges for ever. More accurate ways exist today. Lets work to understand todays technologies and how to improve them where possible.
THx-RNMarsh
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Thanks Scott but these two are not mutually exclusive.
This one I hadn’t thought of. Thanks
Right. The topic was the three hardboard panels
The acoustic center on cone drivers moves a bit with frequency. One more element of uncertainty.
Can you think of some?
Right, thanks. I measure it.
I spend time listening to music with the measured delay dialed in. Then I deviate from that delay set and I listen again for some time.
I do that in steps up and down and this is how I say I can’t find any difference with music.
Ouups!
Then what I wrote there was quasi wrong
Hiten thanks for the link
George
Regarding the current combination (one year cooking) for which I have the numbers.
The omni 4inch Jordan in 40Hz MLQW is high passed (Bessel) at 160Hz and a 12inch woofer low passed (Bessel) at 80Hz. Woofer’s cone is close to the port of the MLQW and 90cm away from Jordan cone.
I listen from 2m to 5m away
The adjustable delay is on the Jordan.
Adjusting from 0ms to 3.5ms (corresponding to a sound air distance of 0m to 1.2m) I hear no difference.
With a delay of 4ms to 4.5ms and above (max 7.5ms) I hear the bass beat becoming smoother and mellower, nothing else.
George
Attachments
Yet another benefit of near field monitoring: the response on axis of the better coaxial drivers such as the Tannoys is extremely flat and in the near field largely unaffected by any lobing, comb-filtering or other diffraction artifacts. With well-recorded sources my experience is they image better than other non-coaxial designs except for perhaps some ESLs like the ESL-63 which interestingly is also a coaxial radiator.
Near field monitoring is not without it's challenges; the sweet spot can be very small requiring the listener to remain still to achieve best and most stable imaging. Despite this, I spend 90% of my time in the near field of a pair of coaxial speakers when doing audio work due to their superior reliability of reproduction unimpeded by room issues.
For an omni with No directivity. And listening in far field. No room carpet or heavy drapes etc. Lots of delayed reflections and room influence.
OK.
THx -RNM
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George,
That was not treatment just recognizing what is in the room. For example a window frame with the window closed is a Helmholtz resonator, broad tuning perhaps. Drapes or window shade is a diaphragmatic absorber.
But putting artwork on the walls will change the room. Framed behind glass on a plaster wall will give a bit of diffusion. A canvas on a frame, low frequency absorption and I even have a coat rack in the room to add some full range absorption and diffusion.
Now my office system is a concentric coaxial system with a rear horn load driven by a scaled up version of a class A amplifier. Or as some here prefer a near field system.
Both types can have advantages based on what was actually recorded and the type of music.
For example my preference for loud Rap music is played inside an automobile, with a monster sound system and on a road at least a few miles away from me.
That was not treatment just recognizing what is in the room. For example a window frame with the window closed is a Helmholtz resonator, broad tuning perhaps. Drapes or window shade is a diaphragmatic absorber.
But putting artwork on the walls will change the room. Framed behind glass on a plaster wall will give a bit of diffusion. A canvas on a frame, low frequency absorption and I even have a coat rack in the room to add some full range absorption and diffusion.
Now my office system is a concentric coaxial system with a rear horn load driven by a scaled up version of a class A amplifier. Or as some here prefer a near field system.
Both types can have advantages based on what was actually recorded and the type of music.
For example my preference for loud Rap music is played inside an automobile, with a monster sound system and on a road at least a few miles away from me.
Intentional. Some HF directivity added by the 3.5inch paper Hitachi facing fwd.
I can’t seat on a chair at a sweet spot just to listen. No way.
Summer version (May to Oct
)True. One meter from the wall is not what I want but it’s a living room. Heavy drapes in the winter make things better.
Good for the kind of music I listen to.
The upper lows, mid and highs are good.
The bass section is still under adjustment
Ed you are the one
Please tell me how should I describe a sofa (there are two) just to make some impression
Far far field
George
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FWIW, currently I am running an active sub placed dead central between two tall narrow loudspeakers (bass-2 x 4.5", mid-1 x 4.5", highs-1 x 1" surrounded by acoustic pinboard) spaced 1.5m apart with an air mattress laying horizontally on top of the sub and firmly against the back of the L/R loudspeakers.
With this arrangement the sound anywhere in the room/house (and outside too) is delightfully clean clear, present and enjoyable...goes quite seriously loud too.
When sitting on my Ikea Poang chair placed into the nearfield, the L/R and depth imaging is 3D holographic due to essentially complete lack of early reflections caused by diffraction and cabinet rear radiation.
Notable also is the importance of fore/aft time alignment positioning of the sub and precise central positioning wrt the L/R cabinets....IOW the old conjecture that subs are position non critical is a complete crock.
With sub level and roll in point dialled in correctly the overall image positioning, clarity and musicality is better than headphones....bass chest/torso/leg vibration adds to the fun.
The only downside I find is the wide ranging variability in mastering of the low end...on general pop/rock music the low/bottom end is all over the shop and requires tweaking to suit/correct the particular track/album in play.
George, it looks like you are having fun with your system, but with your arrangement as I see it you have you have no hope of precise imaging or flat response, and with so much reflections you ain't ever going to optimise or hear time alignment.
Dan.
With this arrangement the sound anywhere in the room/house (and outside too) is delightfully clean clear, present and enjoyable...goes quite seriously loud too.
When sitting on my Ikea Poang chair placed into the nearfield, the L/R and depth imaging is 3D holographic due to essentially complete lack of early reflections caused by diffraction and cabinet rear radiation.
Notable also is the importance of fore/aft time alignment positioning of the sub and precise central positioning wrt the L/R cabinets....IOW the old conjecture that subs are position non critical is a complete crock.
With sub level and roll in point dialled in correctly the overall image positioning, clarity and musicality is better than headphones....bass chest/torso/leg vibration adds to the fun.
The only downside I find is the wide ranging variability in mastering of the low end...on general pop/rock music the low/bottom end is all over the shop and requires tweaking to suit/correct the particular track/album in play.
George, it looks like you are having fun with your system, but with your arrangement as I see it you have you have no hope of precise imaging or flat response, and with so much reflections you ain't ever going to optimise or hear time alignment.
Dan.
George,
I think I see your problem, the soldering iron tip is not quite clean enough!
A sofa is an absorber of about 10 sabins per meter. Very useful as when one sits on it they cover up some the absorption. In doing so they and their clothes provide about the same amount so the room acoustics don't really shift much.
I think I see your problem, the soldering iron tip is not quite clean enough!
A sofa is an absorber of about 10 sabins per meter. Very useful as when one sits on it they cover up some the absorption. In doing so they and their clothes provide about the same amount so the room acoustics don't really shift much.
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