Floyd and I do different things and discuss different things. Floyd talks about what is audible and why and I talk about how to achieve that in an actual design. The two books have almost no overlap at all. One is for evaluators and the other for designers. Its good to do both.
Hello DDF
If I am using a measurement system how am I blind?? My HT set-up has been set and forget for several years now. It took quite a bit of work to get me there. If I tried a different speaker system there I would have to start over but I would still go for the target curve I have now.
Rob🙂
If I am using a measurement system how am I blind?? My HT set-up has been set and forget for several years now. It took quite a bit of work to get me there. If I tried a different speaker system there I would have to start over but I would still go for the target curve I have now.
Rob🙂
Every strategy will work with some music in some rooms some time just as some investment strategy will work with the stock market.
Pray share with us the details of your methodology since your earlier mention of gated, etc. lacks specifics of how what you do an that provides definitive criteria about what to adjust?
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Good and valid points esp. about "impacting tonality" and maybe quiet significant and not just "second order". You have a skill at camouflaging important "take home messages" in cool engineering language!
I don't know about the voice simulation Schroeder used (the same Schroeder I knew at Bell Labs, I think), but I doubt if testing with a stimulus that simulated the statistical properties would overcome these hearing-factors in mic testing of specific speakers in specific rooms. But such a sound source would work successfully with listener panels despite those factors.
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This relates to the discussion a few pages back about the possibility of realism in terms of the orchestra or the jazz combo being transported into your living room.
I just got back from a service visit to our theater at Vancouver Aquarium. (3D ghosting issues). A nice 128 seat theater with a standard JBL 4675 system.
The show starts with an announcer: "Sit back, relax and enjoy the show..." The fidelity is okay but there is no realism primarily because you are hearing human voice at 80-90 dB obviously at a distance (say 30 ft) in a somewhat reverberent room. It's that husky FM radio voice at an unnatural level.
Compare that to a real person, say a lecturer. They would be using that loud "projecting" voice and might hit a level of 70 dB from that distance. Since the context is wrong you know the speaker (human) can't be real. The large room cues and the high voice SPL level (which contributes a Fletcher Munsen bassiness) are incongruent.
Maybe the same with reproduced music. I can imagine a 4 piece jazz combo in my living room, also a piano, (since there is one). An orchestra, along with a recorded concert hall, doesn't have a great chance in my living room, it just doesn't add up.
I have heard some of my larger speaker designs set up in large performance halls and the effect is wonderful and more plausibly realistic. Clearly you are in a large appropriate space and realism increases. The point is that ultimate fidelity still might not get us fooled about bringing the orchestra into our living room.
David S.
I just got back from a service visit to our theater at Vancouver Aquarium. (3D ghosting issues). A nice 128 seat theater with a standard JBL 4675 system.
The show starts with an announcer: "Sit back, relax and enjoy the show..." The fidelity is okay but there is no realism primarily because you are hearing human voice at 80-90 dB obviously at a distance (say 30 ft) in a somewhat reverberent room. It's that husky FM radio voice at an unnatural level.
Compare that to a real person, say a lecturer. They would be using that loud "projecting" voice and might hit a level of 70 dB from that distance. Since the context is wrong you know the speaker (human) can't be real. The large room cues and the high voice SPL level (which contributes a Fletcher Munsen bassiness) are incongruent.
Maybe the same with reproduced music. I can imagine a 4 piece jazz combo in my living room, also a piano, (since there is one). An orchestra, along with a recorded concert hall, doesn't have a great chance in my living room, it just doesn't add up.
I have heard some of my larger speaker designs set up in large performance halls and the effect is wonderful and more plausibly realistic. Clearly you are in a large appropriate space and realism increases. The point is that ultimate fidelity still might not get us fooled about bringing the orchestra into our living room.
David S.
But bringing the orchestra into my living room is certainly not my goal, why would it be? Having the walls drop away so that I am at the concert, is. It can be done - and on a continuum of "almost there" to excellent.
Small ensemble in the room, OK, maybe.
Small ensemble in the room, OK, maybe.
Hi Rob,
Not blind in measurement accuracy but blind in adherence to a particular target. My measurement system is extremely accurate but each loudspeaker requires some slight differences in end on axis target, IME, to reach its best potential.
Dave Dal Farra
I'm not so sure yours doesn't give good background theory. I just skimmed the "phsychoacoustics" section and it's impressive. I wish I had known it was there. It summarizes a lot of reading I've done much more succinctly/clearly that I have in my blog.
Seems I choose the hard way all too often. I know what I'm reading next.Dan
Yes, I'm aware of this level dependence but it has nothing to do with the point I was raising.
Dave
Given my experience over time and the more I follow this the more it seems to me that for any given recording played back on any given set of speakers as set up in any given room that there's going to be some small range of volume settings for which the perceived response is most realistic, whatever that may be. The rest may also be good (or not), but those will all reduce whatever level of perceived realism was achieved. Whether one sets up by measurements or by ear, as soon as you change the listening level, the perceived response will change. So where does that leave us?
This will always be a never ending quest. Maybe that's good.😉 What would we do for fun if perfection in reproduced response were ever achieved? 😱
Dave
It's a steep learning curve, Dan, but I have faith you'll make it.I wish I had known . . . It summarizes a lot of reading I've done much more succinctly/clearly that I have in my blog.
Eventually . . .
I think we are losing ground again.
There is no way for two speakers to put into your room the 3D pattern of sound any instrument would actually make. So whatever we mean by "great and realistic sound" we do not mean "the walls fall away and I think a saxophone is playing in my room".
There is no way for two speakers to put into your room the 3D pattern of sound any instrument would actually make. So whatever we mean by "great and realistic sound" we do not mean "the walls fall away and I think a saxophone is playing in my room".
You're just not getting it, are you Ben? Why do we not mean that? Or do I simply not understand what you are saying?
Lipshitz (in a paper in the 80s) determined what it would take to recreate a 3D sound field replicating the original (with some acceptable degree of error, can't recall what the acceptable error was). It was 5 loudspeakers, as a starting point. True for anechoic listening only, of course. The room can't possible replicate the long term sound field of a completely arbitrary different room. This of course leads to the call to damp all the early reflections and then in fill with late more chaotic reflections. The later the reflection, the less it impacts tonality.
In the absence of that reference we're left a bit shoe-less in the desert. It's impossible to know what either a live recording sounded like live if you weren't there, or what the recording engineers heard, if you weren't there.
To me, that is the ultimate conceit of the "Absolute Sound" philosophy. The hubris that the listener believes he has a clue what the recording is supposed to exactly sound like. Recall, the adherents in the Absolute Sound revel in describing minute differences in perceived sound.
In the absence of a reliable reproduction target reference, both anechoic and in room, we're left with preference or our faulty perception of what we think accuracy is supposed to sound like. This is why Toole studies preference, not accuracy.
A conceit of the adherents of a blind faith in measurements only, without due wiggle room for listening and tweaking for the listening environment, is that they mistake this for accuracy. Both sides guilty of extreme views founded on not knowing what they don't know.
Dave Dal Farra
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As Carl Jung said "more than 50% of life is feeling" (paraphrased because of defective memory). What matters is enjoyment of the sound, regardless of testing. I enjoy listening to Dark Side of The Moon in "4.1," the unpublished DVD-A version, enveloped in sound as if inside the band. Admittedly this doesn't reproduce a concert environment, but it makes the most of what technology can provide for the sake of enjoyment. Its what Alan Parsons wanted in a "quad" mix, just as the stereo version was what he wanted in a stereo mix. Neither is less true to the reality of perception, just different. I'm not going to give up this just because purists say its impure. I've been there and done that. I think I am becoming a post-modernist.
I was at the opera last week. The tenor and band were going mad. It was LOUD. But the direct sound reaching me was I'd guess, maybe 70 -80 dB. (Probably closer to 70 - I was in the balcony) The rest of the sound was indirect and I was at least 20 feet from the nearest wall. The amplification was due to the reverberance.
When we dial in the loudness of a piece in our listening room so it sounds optimal, I suspect we're trying for the best balance we can get between direct and indirect sound - both of the recorded and local direct and indirect sound.
That might not be all we're doing but it's a big part of it.
The Mets doing Boris Goudonov right now and if you listen to the big bits with chorus you might find you have an itch to adjust the sound.
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Joined 2003
Floor bounce and "near head" interference?
What are the thoughts on floor bounce? Various things can improve it at the LP, but the "fixes" tend to throw response out of kilter off-axis. Is it better to ignore floor bounce as a "natural" occurrence, or, try to "cure" it by selection of driver positions, xo's, floor pads, EQ, etc?
What about the listening chair and the actual listener? Measuring with only a mic at the LP gives one response, add the chair = different response, add pillows in the chair to simulate a person = response 3. What are the thoughts on near-ear interference?
(Just FYI...I use a combination of various gated and RTA measurements to arrive at a pleasing (to me) overall balance. Tilted up on the bottom end, with a slight down tilt on the top...but it can always be better 😉 )
What are the thoughts on floor bounce? Various things can improve it at the LP, but the "fixes" tend to throw response out of kilter off-axis. Is it better to ignore floor bounce as a "natural" occurrence, or, try to "cure" it by selection of driver positions, xo's, floor pads, EQ, etc?
What about the listening chair and the actual listener? Measuring with only a mic at the LP gives one response, add the chair = different response, add pillows in the chair to simulate a person = response 3. What are the thoughts on near-ear interference?
(Just FYI...I use a combination of various gated and RTA measurements to arrive at a pleasing (to me) overall balance. Tilted up on the bottom end, with a slight down tilt on the top...but it can always be better 😉 )
Floor bounce can only be deminished by acoustic treatment, often nothing more than an area rug with pad. Ceiling bounce is also a problem and it's hard to have a rug lay flat on the ceiling, but there are treatments ready built (or even diy designs) available that can help.
Best Regards,
TerryO
When I attended the Don Davis Sound System Engineering seminar back in the 80's, Don set up a 5" speaker on a tripod, maybe 8 ft. out from a calibrated mic, far away from any vertical walls, and ran a frequency sweep. It was in a large conference room with a carpeted floor and cork like "acoustic paneling" hung ceiling. There were cancellations from the ceiling bounce on the order of 12dB at the freq where the reflected signal was a half wavelength delayed, and at all the integral multiples of that frequency. He moved the mic further and closer to the speaker so you could see the cancellations move in frequency. Much more severe than I would have believed. What I've found over time is that a few reflections can be worse than quite a few, because when you have quite a few, they fill each other in. Where one delayed reflection path is causing a cancellation at the listening position, other paths won't be, because they all have different delay times, and therefore cancellation frequencies. There are so many variables in any situation, I'd dampen corners to reduce room ringing, and from there trust my ears more than most would. Sometimes, the more you fix things, the more clear and obtrusive the remaining imperfections will be.
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