Well I definitely don't want my studio recordings to sound like live sound. I want them to sound like they did listening to the original monitors. So given that I want the Control Room seat. I want to hear what's there and every note of it clearly and distinctly. So I want accuracy to the original recording warts and all.
If it's live it goes into the HT rig if possible. That's another kettle of fish.
Rob🙂
If it's live it goes into the HT rig if possible. That's another kettle of fish.
Rob🙂
As far as how loud the bass should be at 30Hz. Personally I tend to enjoy a bit of the boost on the very low end now matter how loud or quite overall volume is. I never like the idea of the "loud" button that boosts bass as the volume is reduced. The boosted bass response when the volume is low seems contrary to what I expect to hear at those levels. I end up focussing on the bass. YMMV. I haven't used such a thing in many years--since my teens. Some of them just seem to boost bass all the time regardless of volume. So I don't think there was ever a standard way to do it.
I like that term "Halo Effect". Made me laugh.
Dan
I like that term "Halo Effect". Made me laugh.
Dan
Wide dispersion (120° and wider) generates 15th row concert hall spaciousness at the sacrifice of imaging. No big deal, there's none there live, either, in the reverberant field. In combination with rolled-off highs, this is the stuff of Villchur, Allison, et al., classic New England design sensibilities. They were striving to achieve 180° constant directivity. Modern multi-channel does it better.
Narrow dispersion (60° or less) produces the familiar solo listener "Head in a vice" precision imaging with the only spatial cues being those in the recording itself, and no artificial ambience.
Moderate dispersion (60° - 120°) constant directivity allows adjusting the balance between imaging and spaciousness in typical small listening spaces via the simple expedient of toe-in.
[That's Zilch's synthesis of the directivity dealio.... 😉 ]
Narrow dispersion (60° or less) produces the familiar solo listener "Head in a vice" precision imaging with the only spatial cues being those in the recording itself, and no artificial ambience.
Moderate dispersion (60° - 120°) constant directivity allows adjusting the balance between imaging and spaciousness in typical small listening spaces via the simple expedient of toe-in.
[That's Zilch's synthesis of the directivity dealio.... 😉 ]
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I wonder if I could have some help interpreting these impulse responses please?
dantheman? johnK? (because these are taken on an OB).
The baffle is 600mm wide, 1000mm high. The mid and tweeter are centered. The mid is a nominally 6.5" driver, actually 120mm in diameter. It is centered 400mm from the top.
The tweeter is on a 12" waveguide, centered 180mm from the top.
All relevant because I would like to know the difference between expected "edge" diffraction, and the mooted possibility of a double impulse response, inherent? to a dipole configuration.
The graphs are resized images from the DEQX measured impulse responses, before it does its stuff.
The first shows the tweeter and mid (drivers off-set obviously) taken on the tweeter axis at about 2m.
At about 10.1 (solid marker line), there seems to be an out-phase? component to the mid response, which in itself seems to decay nicely.
The time seems to correspond to the closest baffle edge (if my arithmetic is correct!!!).
Is this what you would expect to see from edge diffraction (i.e could be eliminated with the use of a baffle as a figure of eight in cross section, as suggested by Earl), or is it the origin of a new impulse response due to cancellation of front and back waves? My gut feeling!!! is that a null wouldn't cause this?
Since it has been proposed on the Beyond the Ariel thread that there is a second impulse on a dipole, this is the crux of my question.
There also seems to be something out-of-phase with the tweeter at the dashed line (which doesn't seem to occur at 45 degrees, on the second graph- 0 degrees green, 45 degrees orange). The edge of the waveguide is closer to the edge of the baffle than the mid is, but if the origin is the driver itself, it would be further.
According to the graph, it happens relatively quicker, and there can't be dipole cancellation!!, so is this edge diffraction originating from the edge of the waveguide mouth, before leaving the edge?
The out of phase bit with the tweeter doesn't seem to occur at 45 degrees?, but otherwise the impulses seem to track pretty well.
The third graph shows the mid at 0 degrees- blue and 45 degrees- brown.
Things seem a bit more complicated here, as the 45 degree measurement seems to trend to an out-of-phase response. What can we glean from this??
David
dantheman? johnK? (because these are taken on an OB).
The baffle is 600mm wide, 1000mm high. The mid and tweeter are centered. The mid is a nominally 6.5" driver, actually 120mm in diameter. It is centered 400mm from the top.
The tweeter is on a 12" waveguide, centered 180mm from the top.
All relevant because I would like to know the difference between expected "edge" diffraction, and the mooted possibility of a double impulse response, inherent? to a dipole configuration.
The graphs are resized images from the DEQX measured impulse responses, before it does its stuff.
The first shows the tweeter and mid (drivers off-set obviously) taken on the tweeter axis at about 2m.
At about 10.1 (solid marker line), there seems to be an out-phase? component to the mid response, which in itself seems to decay nicely.
The time seems to correspond to the closest baffle edge (if my arithmetic is correct!!!).
Is this what you would expect to see from edge diffraction (i.e could be eliminated with the use of a baffle as a figure of eight in cross section, as suggested by Earl), or is it the origin of a new impulse response due to cancellation of front and back waves? My gut feeling!!! is that a null wouldn't cause this?
Since it has been proposed on the Beyond the Ariel thread that there is a second impulse on a dipole, this is the crux of my question.
There also seems to be something out-of-phase with the tweeter at the dashed line (which doesn't seem to occur at 45 degrees, on the second graph- 0 degrees green, 45 degrees orange). The edge of the waveguide is closer to the edge of the baffle than the mid is, but if the origin is the driver itself, it would be further.
According to the graph, it happens relatively quicker, and there can't be dipole cancellation!!, so is this edge diffraction originating from the edge of the waveguide mouth, before leaving the edge?
The out of phase bit with the tweeter doesn't seem to occur at 45 degrees?, but otherwise the impulses seem to track pretty well.
The third graph shows the mid at 0 degrees- blue and 45 degrees- brown.
Things seem a bit more complicated here, as the 45 degree measurement seems to trend to an out-of-phase response. What can we glean from this??
David
Attachments
Hi,
since your driver mounting is symmetric, the reflections
from the side edges arrive at the on axis measurement
position at the same time.
That rather strong reflection with the midranger in the
first picture may be well explained this way.
Asymmetric mounting is advantageous, to
circumvent those strong reflections.
The "phase shifting" trend observed off axis on
the third picture is due to lobing, which occures
to the sides if the baffle width is more than
about 2.2 x the diameter of your driver.
The maximum baffle size for a 120mm driver
which avoids side lobing would be about
260 mm. If you play a sinewave with your
baffled midranger at a frequency high enough,
the phase will change from lobe to lobe if you
rotate the baffle.
I do not know what happens with the WG tweeter,
but probably the tweeter is less affected from
the baffle edge reflections, because the WG
"hides" them for the tweeter. Reflections may well
also be due to WG mouth ...
Remember that there is no back radiation for the
tweeter so the diffraction effects would be less
pronouced even without the WG.
There is no "inherent double impulse response" with
dipoles. But peaks and notches in frequency response
due to baffle diffraction are more pronounced than
with a closed box of same baffle size. This is also
because of the rear radiation lurking around the edges for
lower frequencies where the drivers are non directional.
The more important it is, to account for those reflections
during design (see above), match the baffle size to the
size of the drivers and find an optimum position for the
drivers.
When the overall sizing is OK, further refinement can
be done by rounding the baffle edges and using absorbent
material e.g. around drivers/baffle edges if necessary.
Kind Regards
Oliver
since your driver mounting is symmetric, the reflections
from the side edges arrive at the on axis measurement
position at the same time.
That rather strong reflection with the midranger in the
first picture may be well explained this way.
Asymmetric mounting is advantageous, to
circumvent those strong reflections.
The "phase shifting" trend observed off axis on
the third picture is due to lobing, which occures
to the sides if the baffle width is more than
about 2.2 x the diameter of your driver.
The maximum baffle size for a 120mm driver
which avoids side lobing would be about
260 mm. If you play a sinewave with your
baffled midranger at a frequency high enough,
the phase will change from lobe to lobe if you
rotate the baffle.
I do not know what happens with the WG tweeter,
but probably the tweeter is less affected from
the baffle edge reflections, because the WG
"hides" them for the tweeter. Reflections may well
also be due to WG mouth ...
Remember that there is no back radiation for the
tweeter so the diffraction effects would be less
pronouced even without the WG.
There is no "inherent double impulse response" with
dipoles. But peaks and notches in frequency response
due to baffle diffraction are more pronounced than
with a closed box of same baffle size. This is also
because of the rear radiation lurking around the edges for
lower frequencies where the drivers are non directional.
The more important it is, to account for those reflections
during design (see above), match the baffle size to the
size of the drivers and find an optimum position for the
drivers.
When the overall sizing is OK, further refinement can
be done by rounding the baffle edges and using absorbent
material e.g. around drivers/baffle edges if necessary.
Kind Regards
Oliver
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Forget about that "double impulse response, inherent? to a dipole configuration". What you hear from the backside of a dipole is simply the part of its edge diffraction which is radiating to the front. And the timing for that rear edge diffraction is exactly the same as for the frontal edge diffraction.
And please forget about that "two point source" model for dipoles, if you are looking at extended sources like cones, domes, ribbons etc. and at any sort of baffle. At 45° your "two point source" model is completely useless in that case.
Rudolf
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bentoronto- I actually believe we agree more or less. One such gentlemen in the Indianapolis Symphony, who is a musician, provided seats in for a show he was playing in and I listened. After the show we went to his house and listened to the recording of the same orchestra and same piece of music in the same hall. I must say it sounded remarkably like the live performance from the seat I had room effects and all. That was his goal. Another gentlemen in New York was after the sound from the Metropolitan which he attended weekly and his system did likewise surprisingly well. I believe there is a lot of "undocumented" work done which has lead a few to systems which really work for the listener. soongsc is one example. Call in pseudo-science if you like but it is working for them as my up front at the podium system works for me. Of course I had to design and build every part of my system from the CD to the tweeter with every part in between. But I have done amps and speakers for a lot of people professionally so there has been some "practice." As stated before, more of a method. In a recording studio the up front and near sound is what most engineers want so... lots of practice.
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Thanks Oliver and Rudolf.
At last I see the 2.2 factor before my very eyes 🙂. (Orion, Nao e.t.c. e.t.c.!!).
I'm still not sure what Jmmlc is demonstrating with the "double impulse", that no-one else seems to go along with. (and is also not my understanding either).
At last I see the 2.2 factor before my very eyes 🙂. (Orion, Nao e.t.c. e.t.c.!!).
I'm still not sure what Jmmlc is demonstrating with the "double impulse", that no-one else seems to go along with. (and is also not my understanding either).
Shame on you for never taking Psych 101. Basically means "the teacher gives high marks on ALL TESTS to that little angel in the third row they think is smart." Anybody else here in this (psycho)acoustic measurement thread that has never taken Psych 101?
i agree with you in almost every detail. But some deeper questions are:
1. Could YOU make your own "loudness" control for your room based on SPL and equal loudness curves (even based on your own ears (if that were remotely possible to do, which it isn't)) and would it sound right to you at any level?
2. If so, would it "work" for all SPL levels?
3. If not, is there any acoustically objectively defensible curve (not counting your own personal preference curve, of course)? Or family of curves that sound right to you?
My bet is that beyond a certain point of technique, music recording ends as a kind of fine-tuning to taste and so, ultimately is sound reproduction (including public spaces) done for the purpose of making people happy.
I sat in on some of the tuning of Roy Thomson Hall. "Hey, this is pretty dead, just the way I like to hear it. Let's me put my ear on the instrument." Wow, did I get dirty looks from the development team and the hot-shot guru from Bolt, Beranek, Newman. Yeah, proved to be a bummer hall to professional reviewers. Not so bad sounding for my amateur ears.
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Brittain cited by Toole:
...
The dilemma is summed up nicely by Brittain who recognized,
in 1939, that "in order to reproduce reverberation naturally it
is necessary for the loudspeaker to envelop the listener
completely.
If these loudspeakers are used to reproduce the direct
sound as well as the reverberation the effect
will be very unnatural, particularly when the source
of sound is known to be small, as in speech" [2].
...
One problem with piston acting loudspeakers is, that they simply
cannot produce a diffuse sound field which is binaurally decorrelated.
Even when reproducing only the reverb of a transient signal on a recording
that has been made in a hall, the speakers will radiate from a rather small
piston acting area. Thereby producing cues for their position by early
reflections in the listening room.
The path differences from speaker to listener for the early reflections
in the listening room are not sufficiently large and random enough to
maintain the diffuse quality of the reverb.
The reverb in the recording is more degraded by room reflections than
"supported" when using piston acting phase coherent loudspeakers.
"Here are the speakers" information is always added. The bad to mediocre speakers
add that unwanted information in a very ugly manner and the better ones
do it in a more decent way.
This may be the reason why the narrrow vs. wide radiation preference
cannot be decided: It always boils down to the question:
What do you want, imaging or envelopment ? Imaging or a larger "ambient"
listening area ? The "either or" character makes chosing the right speaker
dependent from its purpose and the listening room conditions.
E.g. professional and home listeners will decide different, as the pistonic
small radiation area loudspeaker cannot fullfill both criteria but only a
- possibly well chosen - compromise for the given purpose, which may be
denoted by its directivity index.
It simply cannot be decided, because the piston acting loudspeaker is not
able to produce both. And let me add kindly: No matter how many channels you use !
The problem is present in mono as in 5.1 except for installations, where
the room conditions are optimized. For the average living room the problem
stays the same.
You can fumble around with "room correction" by DSP. Fine for a "one listener
on a defined seat" situation indeed. But that is the setting where the problem
can also be minmized using a dry room and a high directivity speaker.
The pistonic loudspeaker itself is the problem.
...
The dilemma is summed up nicely by Brittain who recognized,
in 1939, that "in order to reproduce reverberation naturally it
is necessary for the loudspeaker to envelop the listener
completely.
If these loudspeakers are used to reproduce the direct
sound as well as the reverberation the effect
will be very unnatural, particularly when the source
of sound is known to be small, as in speech" [2].
...
One problem with piston acting loudspeakers is, that they simply
cannot produce a diffuse sound field which is binaurally decorrelated.
Even when reproducing only the reverb of a transient signal on a recording
that has been made in a hall, the speakers will radiate from a rather small
piston acting area. Thereby producing cues for their position by early
reflections in the listening room.
The path differences from speaker to listener for the early reflections
in the listening room are not sufficiently large and random enough to
maintain the diffuse quality of the reverb.
The reverb in the recording is more degraded by room reflections than
"supported" when using piston acting phase coherent loudspeakers.
"Here are the speakers" information is always added. The bad to mediocre speakers
add that unwanted information in a very ugly manner and the better ones
do it in a more decent way.
This may be the reason why the narrrow vs. wide radiation preference
cannot be decided: It always boils down to the question:
What do you want, imaging or envelopment ? Imaging or a larger "ambient"
listening area ? The "either or" character makes chosing the right speaker
dependent from its purpose and the listening room conditions.
E.g. professional and home listeners will decide different, as the pistonic
small radiation area loudspeaker cannot fullfill both criteria but only a
- possibly well chosen - compromise for the given purpose, which may be
denoted by its directivity index.
It simply cannot be decided, because the piston acting loudspeaker is not
able to produce both. And let me add kindly: No matter how many channels you use !
The problem is present in mono as in 5.1 except for installations, where
the room conditions are optimized. For the average living room the problem
stays the same.
You can fumble around with "room correction" by DSP. Fine for a "one listener
on a defined seat" situation indeed. But that is the setting where the problem
can also be minmized using a dry room and a high directivity speaker.
The pistonic loudspeaker itself is the problem.
Right. Thanks Oliver. And that's one more clear reason I have never thought even so simple an instrument as a flute is playing down the hall in my music room.
Everybody know what a "Turing Test" is for computers?
How about a Toronto-Turing Test along the same lines for hifi? The panel of judges sits in a room and listens to music being played in an adjacent room through a 3x4 foot opening in the wall between.
Everybody know what a "Turing Test" is for computers?
How about a Toronto-Turing Test along the same lines for hifi? The panel of judges sits in a room and listens to music being played in an adjacent room through a 3x4 foot opening in the wall between.
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Been reading some of Lynn Olson's thread.....
I found this interesting post
Lynn's comments on polar response supports what I have posted several times (NOTE: I think polar response is important
). Everyone has their own priorities. There isn't one dominating way of building a great speaker.
I will keep posting that its up to each individual to decide what is important to them.
I found this interesting post
Lynn's comments on polar response supports what I have posted several times (NOTE: I think polar response is important
). Everyone has their own priorities. There isn't one dominating way of building a great speaker.
I will keep posting that its up to each individual to decide what is important to them.
@bentoronto
If those openings are designed well, minimized diffraction effects e.g.,
they would outperform most existing speakers, i am convinced.
If those openings are designed well, minimized diffraction effects e.g.,
they would outperform most existing speakers, i am convinced.
I'm not quite sure what you are trying to say here. Could you restate it in a more direct manner? Is that in reference to the "halo effect?" IOW, what are you implying? What it seems like you are saying is impolite and incorrect(not that it matters) in that last sentence.
Dan
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I certainly can relate to that. Once I heard someone playing the piano very well outside a friends home, and thought "I never knew anyone in their family played so well", only to discover it was really the audio system.😀
I agree and i guess it is the only way possible. But many would like
to improve their sound someway.
It should be allowed to provide options for the directions
to go. Without those options many will start changing cables to do
at least something against their frustration.
A discussion may be useful at least, if most of the interesting
or known options have been named. To push someone into a certain
direction cannot be the goal of a discussion.
The first "shameful" was my mistaken belief that it would be clearly understood by any reader as a fun remark and not a moral judgment of character. Sadly, I was mistaken and apologize to you. Some may have noticed that it is a peculiar, old, out-of-place kind of word and that may have provided a tip-off about how I meant it.
"Halo effect".... "angel in third row".... c'mon now.
I'll stand by my assertion, now restated in basic terms as: (1) when you remove "psycho" from audio acoustics, you've cut a big hole in the middle and (2) if you are innocent of education in that part of psychology that addresses hearing, perception, cognition, memory, and test methods, you are unprepared to talk about audio measurements except for the hole that isn't psychoacoustics.
Agree?
Lynn's piece is wonderful and provides great context for talking about real-world performance, except not in some kind of engineering-never-never-land where there are no human trials with people like Lynn. Thanks for posting. But his thoughts that holes in the response curve matter much are contrary to Toole's conclusion long ago.
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Why? That's how dipoles work.
Which is a delayed negative impulse if an impulse is playing from the front.
The front diffraction is another delayed negative impulse. It adds to the one from the rear side. Put another way, a monopole will have a small negative impulse and a dipole with the same baffle size will have a bigger one.
Now obviously, if the driver is bigger than a point and the baffle is some shape other than round, the negative impulse will get smeared. And high frequencies won't light up the edge of the baffle as well as low frequencies. But below Fequal, the two impulse model is perfectly valid. JohnK ran though the Z-plane math of the two impulses in the Arial thread, showing how they are still minimum phase.
Ben, apology accepted.
That's more like what I hoped you were getting at, but you seem to be implying that you do have a great deal of psych understanding when you say others don't (and it's required for this discussion), and yet post things that would obviously rub people the wrong way from the very start of your posting. Once that precedent is set, it takes some time build a positive sense of your character. IOW, we don't exactly have much of a rapport yet and what we do have is less than optimal. When I said said Halo effect made me laugh, I was simply trying to be friendly and build a rapport--not whatever you thought it implied. This is why I never liked psychology--too much merry-go-round, talking in circles and never get anything accomplished type of junk. Grant it this is not in a perception context.
It doesn't seem that any of us are experts in psychology (from reading the posts on this website) and few in acoustics. So maybe we should all stop posting about things we don't know much about?(that's a joke) That certainly doesn't mean we can't learn and understand meaningful insights into the When, What, How, Why of loudspeakers measurements. I don't see anyone posting here that isn't reasonably intelligent and many have a remarkable depth of understanding in auditory perception, acoustics, and loudspeaker design. We can all read and write though we would be wise to spend much more of our time doing the former. Most of us posting here have done just that. Others have not even read the 101 texts.
Dan
That's more like what I hoped you were getting at, but you seem to be implying that you do have a great deal of psych understanding when you say others don't (and it's required for this discussion), and yet post things that would obviously rub people the wrong way from the very start of your posting. Once that precedent is set, it takes some time build a positive sense of your character. IOW, we don't exactly have much of a rapport yet and what we do have is less than optimal. When I said said Halo effect made me laugh, I was simply trying to be friendly and build a rapport--not whatever you thought it implied. This is why I never liked psychology--too much merry-go-round, talking in circles and never get anything accomplished type of junk. Grant it this is not in a perception context.
It doesn't seem that any of us are experts in psychology (from reading the posts on this website) and few in acoustics. So maybe we should all stop posting about things we don't know much about?(that's a joke) That certainly doesn't mean we can't learn and understand meaningful insights into the When, What, How, Why of loudspeakers measurements. I don't see anyone posting here that isn't reasonably intelligent and many have a remarkable depth of understanding in auditory perception, acoustics, and loudspeaker design. We can all read and write though we would be wise to spend much more of our time doing the former. Most of us posting here have done just that. Others have not even read the 101 texts.
Dan
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Only exactly on axis. And nowhere else. At least not for dipoles that are made by men. 😉 It is only valid in abstract mathematical models. So you better forget about it, if you want to talk about real speakers. 😛
But that does not help David to understand his diagram. He needs to know that edge diffraction and the 'second impulse' are the same thing. You don`t hear the second impulse - you hear the ring radiator.
Isn't it time that we talk a bit more sophisticated about dipoles than the two point source model?
Rudolf
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