Pondoro
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Posts posted by Pondoro
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1 hour ago, Chris A said:
I think if you look in the book at the next figure (15.7 in the third edition), you will see the data on different configurations, including with and without center channel.
If you think about it, why would any configuration sound worse when a center channel is properly dialed in and has the right directivity? Subjective perceptions probably shouldn't degrade if all factors were fully under control. My experience is that the researchers themselves sometimes have uncontrolled factors in their setups (such as using direct radiating loudspeakers that have polar control issues, etc.), so small differences in the performance of the configurations shown in the figure above are probably not significant, but the larger changes seen in configurations a, f, g, and h are probably significant, perhaps very significant. The other configurations will be much closer together in performance (the subjective quantity referred to as "LEV" or listener envelopment).
Chris
I absolutely agree - b, c, d, e and i are "identical." For that matter a, f, g and h are identical (to each other). You can read a graph too finely. And the psychology industry is in the midst of the "replication crisis", in which famous and groundbreaking experiments cannot be repeated with the same results. Still this is fun, and the study here is informative.
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23 hours ago, Chris A said:
Yes, but most surround channels are typically only given lip service in practice, even in commercial cinemas. But you've got it right. The lower their response, the more effective they actually become to add to the sense of envelopment.
One of the better figures from Toole's book shows you the effect of placement of the surrounds. Note that one of the most effective surround channel arrangements actually put the surround loudspeakers forward of the listeners, not aft (ref. configuration "(b)"):
<SNIP>
Chris
I've been staring at this for a day or so now. It appears to me that b, c, d, e and i are basically "equal." Not "the same" but to their audience they were equally good. I sure wish they had included 3 speakers across the front - Left - Center - Right. Option i is the same as d, scores a tiny bit worse (again I would say, "The same") but requires an extra speaker and amp. I bought a third speaker exactly to try the PWK method. As I said I will run it with whatever algorithm Yamaha has built into my receiver as well. But this study, which did not ever try simply adding a center, seems to show that a center did nothing, at best, when added to configuration d.
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14 minutes ago, Chris A said:
As long as their frequency response reaches down to ~30 Hz or below with clean, distortion-free bass, I guess you could use "full range" drivers. I'd think that the modulation distortion would begin to eat you up at any useful SPL, however...I'd rather have a bit more clean SPL capabilities.
Chris
I didn’t realize such low frequency info was important to surrounds. For home theater I should have known, I have been near controlled explosions, the rumble coming back from surrounding hills differentiates the truly large explosions from small ones. All explosions overwhelm the senses, even with good hearing protection, at the moment of the blast. It is the thump in your chest and the echoes that tell you, “That one was big!”
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1 hour ago, Chris A said:
Remember my comment about "how humans hear". It's about what the psychoacoustic requirements are, not typical surround loudspeaker capabilities, which are often not designed to support the psychoacoustics requirements.
The surround channels are usually "echo channels" that are attenuated in high frequency content because of frequency-dependent air absorption & diffraction, and interior venue surfaces that are more effective at absorbing and scattering HFs than LFs. So the echos are always low-passed. That's what you're trying to recreate.
So surround channels could be four to ten inch full range single speakers, and save a lot of money.
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51 minutes ago, Chris A said:
In the example that I posted above, it's clear that what's being done by different pieces of gear is not equivalent, although they're advertised as being equivalent. I hear those differences, and I don't usually like the synthesized implementations of 2-->5 channel that AVPs/AVRs use. Finding out what they're actually doing is usually a lot more difficult than just listening to the results and judging for yourself if it is better or worse.
I think the reason why some of the folks on this forum still use PWK's method, and not because it's necessarily superior, but because it's a user-controllable and known process, even though it may significantly narrow the apparent stereo soundstage. If you set the loudspeakers along the long wall of an oblong/rectangular room, then the loss in apparent soundstage width isn't noticed as much. I think PWK knew what he was doing in 1959 when he published the article on 3 channels from 2 channel channel sources. He had also apparently experienced using the Bell Labs setup that was pioneered perhaps 15-20 year earlier, and he understood the pros/cons of what he was proposing. I'm not sure about the synthesized modes that we get today in our AVPs/AVRs.
Nowadays, you get the algorithms in canned fashion with bells and whistles that you didn't ask for put in, ostensibly because someone in marketing though it sounded "better than the competition" (probably using questionable recordings in the first place to make their judgments).
JRiver seems to have a better handle on things in terms of the signal processing for psychoacoustical effects, but I can't say that I have first-hand experience listening to what they've done, and I certainly don't know what they've actually implemented.
Caveat emptor applies..."let the buyer beware".
Chris
I will certainly compare my Yamaha-generated center channel to the PWK method some day. I’ll need a center channel amp and some free time. I bought the KP-250 because it was cheap and had nearly the same design as my two Heresy speakers basically to try as a center. I'd like to hear the PWK method for historical purposes, even if I eventually decide the modern algorithms are better. I'd actually love to hear all the algorithms mentioned in the papers as well as the PWK method. Not as a blind test, I'd like to hear them and compare out of curiosity.
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6 minutes ago, Delicious2 said:
OK, so it is still breathing. 😆
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28 minutes ago, Chris A said:
Let me give you an example, in this case from the last link I posted:
Notice the center channel here is not just padded down, but a low pass filter is added. I find this to be a problem (and I hear it in some of my multichannel recordings--and it sounds odd). I would like the sound field coming toward me to be more representative of what the microphones actually recorded, and not with a hole in the center of the soundstage that is based on frequency(...?...). I could write a lot more on this subject, but I'll refrain here.
If I were to try to implement the old Polk Audio SDA monitor (ca. late 1970s) "cancellation of the cross-talk between left and right channels, and left and right ears" using stereo loudspeakers only, I would send an out-of-phase component to the front left (FL) channel at a low level and the opposite to the right channel--like Bob Carver did it in the late 1970s-early 1980s to simulate the same thing, but using a preamp only and analog op amps in a separate/selectable processing loop if you sit right on centerline between the left and right channels. The apparent stereo image goes from ±45 deg to something like ±120 deg instantly--using only stereo speakers (not three channel). But you have to sit right on-axis for it to work. With three channel, you use a schema like the stereo-only method, but you have a bit more freedom to play with the apparent soundstage so that it is more stable if you're not sitting directly on the centerline between the two loudspeakers.
Additionally, the above diagram shows a ±90 deg phase-shifter on RL and RR channels. This introduces frequency-dependent time delays on the rear channels, something that I would not like. The simple time delay would suffice to recreate an echo-channel effect without the frequency-dependent delays.
Note that all of the above is wrapped up with how humans actually hear, and not how machines/arrays of microphones perceive the sound field. That field is called "psychoacoustics", and anyone having much more than a passing interest in hi-fi audio really needs to understand the basics of that field, too. I recommend Floyd Toole's book.
Chris
As Quad died in the 1970's "Time Delay" units were briefly popular. You had two channel stereo in front and variable delay in the rear two speakers. Some loved it, said it was "Quad without the format war incompatibilities", purists called it "distortion."
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11 hours ago, Chris A said:
You can read about a likely implementation of your Yamaha AVR here: https://www.aes.org/journal/sample_issue/JAES_V50_11_PG914.pdf
It's not a simple answer if you're using a synthesized 3.1 mode.
Chris
That is an interesting, but very technical, article. I’m a mechanical engineer so I understand the math, but the signal processing stuff is a bit beyond me. I am very familiar with the original Klipsch article that they refer to. It appears they can improve on his simple additive method. I need to spend some serious time listening to songs in both traditional stereo and synthesized center mode. I have a pair of Heresy Ones and a single Kp-250 for the center. The KP is noticeably louder (I substituted it for one Heresy to compare), but I can adjust center channel level.
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On 11/8/2020 at 2:07 PM, Edgar said:
Finally, here is the tone burst response of the closed box. Best of the bunch. And that, I believe, is what people mean by "fast bass".
Right, by “fast” they mean quick response, as shown in your graphs. Thus the rock song with machine gun double kick drums wants fast more than deep. The church organ pipe that comes on at 20 Hz and then sits there for a half note or longer doesn’t need fast. Fast is always good but not necessarily required. I’d love to see your graphs for a fast kick drum and a ten foot wooden or metal organ pipe. I’ll bet the pipe is “slow”, think about getting all that air moving.
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On 12/5/2020 at 12:23 PM, HIRES_FAN said:
I use a 5.2 setup for multichannel stereo with ELAC speakers, dual subs and a Yamaha RX-A3080 receiver. 2 Surround speakers are at right angles on either side of listening position. I don't have flexibility on the surround speaker placement and restricted to 90 degrees at the moment.The Yamaha has a option for front/rear balance on the multichannel stereo mode, which is a very useful feature for this mode. I run it at +1 in favor of the fronts/center vs the 2 surrounds. It sounds amazing and makes my $$$$ 2 channel setup sound lame at times.
I just got a Yamaha RX-V385. I was thinking of using it with stereo CD's in 3.1 mode, Front Left, Front Middle and Front Right with a sub. What content does the processor send to the front middle?
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This is actual wiring on a (Russian) plane that is in use. But not for the audio system.
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18 minutes ago, Dave A said:
Thank Audiogon. I learn about all the really cool cutting edge tech over there. Like these for instance. https://www.audiogon.com/listings/lisa65ia-audio-magic-ce-generators-set-of-3-brand-new-better-imaging-details-dynamics-tweaks
You run your speaker cables through the little hole in the middle and magic happens.
I had a recording of my 7th grade kid's junior high band, it was awful, they had all been playing for only a year, no one was in time or in tune. I bought four of the clean energy generators and the band sounds much better, everyone is in tune and they are all right in the beat!
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The sound gets twisted out of phase when it goes through those wire nuts! (did I start something there?)
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What irony! This morning I was messing around behind our TV and a crimp-connector came loose, I had to redo it. It connected an aftermarket amp to a Denon subwoofer that I had repaired (amp had died, speakers were OK.) I should have soldered!
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Menards has heat shrink tubing. I'll expect other big box lumber and appliance stores also stock it.
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Here you have three steps - A, B, C, showing how to position the shrink wrap. Dashed lines are "not yet shrunk" and solid black is "shrunk."
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Thinking more. Slide a long, larger, piece of heat shrink over both wires, then off to the left or right in the picture above. Then slide a shorter piece of smaller heat shrink onto each longer stub. Connect the wires. Slide the shorter pieces of small heat shrink over the bare areas and shrink it. Then slide the longer piece of heat shrink over the entire joint and shrink it.
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3 hours ago, Marvel said:
It's 22 gauge... and you can just add on to one end. Are the wires on the satellites detachable? If not, splice on some more... the electrons won't care.
But, do your wires like my pic. That way, even if tape comes off, they won't short together. The wire should have a stripe or marking on one side, so you can get the polarity correct.
(Borrowing Marvel's sketch) This method, slide the heat shrink tube fully on to the longer side (each longer side gets a piece of heat shrink). When the wired ate twisted and (I hope soldered) the heat shrink slides over the bare metal and gets "shrunk" with a hair drier or other hot object.
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I would cut in the middle and add. You can use the same gauge or larger wire (remember smaller numbers = thicker wires, 16 is a lot larger than 22.)
Separate the two conductors by peeling the twin wires apart. Then strip about 1/2" to 3/4" bare.
Do you know how to solder? Solder them. Remember to make the joint strong mechanically, don't rely on solder alone to be strong enough. Before you solder them slip some heat shrink tubing over each conductor and up out of the way of the bare part.
After you solder slide the heat shrink over the bare part and shrink the tube. No bare metal should be showing. Look close! If bare metal shows use electrical tape to cover it.
Are your joints ugly? Are they visible? If both answers are "Yes" disguise the joints with colored electrical tape, you can buy it in a variety of colors.
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Another Newbie to this stuff. I know all about wireless routers but have never bought one that will accept an SD card. I know all about SD cards. So if I buy a wireless router that will accept an SD card I can easily fill the SD card with songs. If I buy a streamer with built in DAC that plugs into my receiver or amp I can easily tell the receiver or amp to "take your input from the input where the streamer resides." But how do I tell the streamer to "Go look at that wireless router and play the stuff that you find there"? That seems to need a screen, on a computer or elsewhere.
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I would try to isolate the speakers and power amp and see if they work together. Can you drive the power amp with a tuner or CD player? Do you have a preamp? If the power amp and the speakers sound good when driven by a CD or a tuner then you at least know they and the cables between them are working.
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On 11/28/2020 at 8:05 PM, baron167 said:
If your budget can accommodate it, go for the Yamaha A-S1200
Sent from my iPhone using TapatalkThose look awesome. I do not mean that they "look like they sound awesome." I mean they look awesome. I am sure they also sound amazing.
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This is getting fun. I'm gonna buy some cheap cloth and try a couple of times before I risk the real stuff. .
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29 minutes ago, RandyH000 said:
it is glued on a JIG
So what if I laid the board down on a piece of sacrificial plywood, outside up. Speaker holes already cut out. Paint the board with glue that will dry clear, a very thin coat. Carefully lay the cloth on the board and pin it down around the perimeter (pins go into the plywood, not the speaker board.) Let it dry. Pull the pins. Turn it over so now the outside is down. The cloth is larger than the speaker board. Fold the cloth over and staple on the back.
I am leaning towards just stapling the cloth to the back, no glue. That is the conventional way shown by the YouTube gurus, and would be fairly easy to correct if you got a wrinkle or a sag.
Looking for input from someone who has been there and done it.
Floor Standing Speaker Placement
in 2-Channel Home Audio
Posted
I am really glad that you toed them in!