That's not my experience at all. Comparing an omni speaker and speaker with high directivity, high directivity is more revealing of the source material. Our brains are great at spatial filtering given that we only have 2 ears, but there's only so much we can do. Since our ears are aligned horizontally, we have trouble filtering out reflections from the floor, ceiling, and front wall. Side walls are easier to ignore, but we need some separation between the speaker and the side wall. If the speakers are at +/- 30 degrees, we probably don't want any reflections coming from between +/- 70. I believe the impact of a reflection is related to its azimuth, elevation, delay, and magnitude. Rules of thumb that ignore any of those variables will be incomplete.
It's not hard to understand why the omni speaker lacks clarity in all but the largest / best treated listening room: any time it produces a sound, that sound has to overcome the reverb of previous sounds in order to be heard. Our brains try to cut through the reverb for us, but loud echoes from angles similar in azimuth to the speakers are problematic. In my experience, I had to concentrate very hard when listening to omni speakers, in order to try and make out the lower amplitude layers of music captured in the recording. With highly directive speakers, I can relax and still hear everything.
I don't mean to imply that we interpret omni speakers to sound bad. I don't think that's the case. I think we recognize that a high quality omni speaker is high quality. Our brain can figure that out, but it can't uncover everything the room reflections are hiding.
I find that my personal taste is for very dry recordings, even on speakers that are highly directive vertically. Others may respond differently to reflections, and might even willingly accept a trade-off in clarity for the experience that reflections bring: like having the musicians in your room. (Here I'm talking about early reflections from angles near the speakers, like those from the floor, ceiling, front wall, or close side wall.) Having addressed these reflections in my system, it's more aligned with the "you are there" camp. In fact, my wife woke me from a dream the other day, and I thought to myself "this experience is familiar". It took me a second, but I realized that waking from a dream was much like opening my eyes after listening to music with my eyes closed for extended periods. I just don't expect to see a couple of speakers and a wall in front of me. The highly directive speakers don't call attention to their position in the room, and do a much better job of disappearing than others I've heard.
YMMV.
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Edit to post 160: the text "Direct sound, followed by 0-30 ms of silence /inaudible reflections then ..." was a bit ambigous: Should be: Direct sound, followed by 0-about 15 ms of silence /inaudible reflections and then at around 15-30 ms audible reflections, fools your brain of you having a much larger room than you actually have.
Well I've certainly had that happen
. My dislike for mp3 only grew stronger due to having better sound as well. Some things might stand out a little more.Like the engineer working on the Back to Black album from Amy, what was that guy thinking!
And people say it's not important to have speakers that can play square waves
It's just that it's a bit overused for people defending their speakers. Like I said, there's most probably a good cause or reason if something sounds wrong or plain awful. Most music doesn't fall into that category. Although the loudness wars didn't exactly help either.
I like that comparison
. I sometimes think I've build a time machine...
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Yeesh - that's an interesting engineering choice, there...
I know you're joking, but I do believe a good test of a loudspeaker is how well it navigates this sort of thing. Many do talk about really good speakers revealing every little production flaw. But I think there's a point beyond that, where a really good speaker can properly articulate artifacts like distortion in a recording, neither sharpening nor blurring them. I've heard my system do this, although I'm still not exactly sure how it's happening.And people say it's not important to have speakers that can play square waves
Isn't that just very high frequency content, you'd probably need a super tweeter for that?
Sorry, Scott, I'm not sure what you mean. Harmonic distortion products tend to manifest in the higher frequencies, since they are frequency multiples (products) of the waveforms they are distorting. But yes, as long as the fundamental frequencies being distorted are below 6 or 7 KHz (i.e. pretty much the entire range of musical instrument pitches), any distortion products will potentially be audible, even to old geezers like us. And of course that's just harmonic distortion. Intermodulation distortion produces lower-frequency artifacts.
And of course that's just harmonic distortion. Intermodulation distortion produces lower-frequency artifacts.
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In terms of revealing flaws in the playback system or source material i can give 2 other examples besides Peter Walker saying that because his elctrostat was more accurate it sounded "dreadful".
There used to be a warning label on CDs at the bottom for remasters saying as much. "The Music on this Compact Digital Disc was originally recorded on analog equipment. We have attempted to preserve, as closely as possible, the sound of the original recording. Because of its high resolution, however, the Compact Disc can reveal limitations of the source tape."
****Spoiler Alert
Most of the time the easiest thing to pick up on for a Tape transferred to digital is tape splices. Tape splices would be blamed on the vinyl most likely prior to this but now you can hear them and they are not vinyl pops.
I think visual analogies work better because people pick up on visual artifacts much easier than they do audio ones. Take an old TV show produced and shot on Beta and then display it on a new LED or CRT screen. The inaccuracy of the old glass onion faced crt tvs used to make the perceived fidelity near perfect - due to it's smearing and lack of sharpness. But now if you play that same things without an analog picture tube it will reveal all the flaws even though in all measurable ways the LCD or LED should be better perceptually it only serves to reveal more flaws in the source material because the producer could not even monitor those flaws accurately at the time or they were negligible.
There used to be a warning label on CDs at the bottom for remasters saying as much. "The Music on this Compact Digital Disc was originally recorded on analog equipment. We have attempted to preserve, as closely as possible, the sound of the original recording. Because of its high resolution, however, the Compact Disc can reveal limitations of the source tape."
****Spoiler Alert
Most of the time the easiest thing to pick up on for a Tape transferred to digital is tape splices. Tape splices would be blamed on the vinyl most likely prior to this but now you can hear them and they are not vinyl pops.
I think visual analogies work better because people pick up on visual artifacts much easier than they do audio ones. Take an old TV show produced and shot on Beta and then display it on a new LED or CRT screen. The inaccuracy of the old glass onion faced crt tvs used to make the perceived fidelity near perfect - due to it's smearing and lack of sharpness. But now if you play that same things without an analog picture tube it will reveal all the flaws even though in all measurable ways the LCD or LED should be better perceptually it only serves to reveal more flaws in the source material because the producer could not even monitor those flaws accurately at the time or they were negligible.
My fault, I'd gotten hung up on square waves and was thinking you need a very large bandwidth to reproduce them.
That is correct. If you do a Fourier expansion on a square wave you'll quickly realize that the harmonics >3rd are required to make it only "look" square and that's assuming a perfect 50/50 duty cycle (odd harmonics only). If you change the duty cycle you'll get both even and odd harmonics. Given a 3Khz square wave the 3rd harmonic is already at 9KHz, the 5th harmonic at 15Khz.
So the only square wave you can expect to reproduce will be at lower frequency, assuming you need at least 5 harmonics (1x, 3x, 5x, 7x, 9x) to get a "sqaure wave".
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Well, to avoid misunderstandings, some ETC diagrams
Prior to treatment, some bad, strong and early reflections giving a too short ISD gap. No late good and strong reflections in the 15-30 ms time period.
After treatment, the non wanted early strong reflections have been attenuated to below -20 dB compared to the direct sound. Some strong wanted late reflections around 28 ms, closing the ISD gap.
The time axis is extended to 325 ms, -to reveal if the room has a smooth decay or not. Pretty good, no bad "bumps" (echos) after the reflection at 28 ms. From the angle of the Schroeder integral (the black line) the decay time for -60 dB in the room can be calculated to about 240 ms. (RT60 as some call it.)
If those CD's were made in the early stages of digital: run!
All samples here fall into the category: measurable. Mastering for CD and for Vinyl has its differences too. I'm a huge Led Zeppelin fan. I have all albums on (early) Vinyl (pressings). I have them on a variety of CD versions as well. Including remastered and boxed sets. Yet it wasn't until the recent 2015 remasters that I finally was able to thoroughly enjoy them again. After all these years they sounded like my old vinyl albums again.
I like Van Halen too, and aside from the first album mastered by Steve Hoffman for a DCC Gold release, the CD's are lacking compared to the vinyl versions. Even their latest remasters (2015) which has a high resolution version (24/192), that's the best up till now, while there's a "mid" resolution (24/96) version and the regular CD (16/44.1) version which both are compressed and loud in comparison.
It's obvious to see in the Dynamic Range Database there are differences.
I've checked the High Res vs the Steve Hoffman release. The mastering differences are pretty obvious. Steve's DCC Gold disk has a better balance and higher bass levels (a lot like the Vinyl album had). I wish they would have listened to the original vinyl sound in 2015 and mastered it like that, Mr. Hoffman showed us it is possible.
While this isn't comparable to what you were saying, I guess a lot of things go wrong in the modern world too. All the right equipment and what do we do? Make it loud!
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Thanks, that's clear now. Very impressive results. I guess the reflection around 6.5mS was potentially a problem, borderline too early?
Being a committed OB head (so far anyway) I'm particularly interested in this.
Where would you draw the early reflection line? Presuming it's that simple of course
FYI - It's up and running. I'm still trying to decode the results.I'd love to see an APL_TDA plot from your setup, as measured at the listening position. Not to "judge" anything, mind you. Just sheer interest in how that setup would look.
Before I ever got the idea to build my line arrays I've thought about Omni as an option. (among open baffle and horns and whatnot)
Ultimately I chose what I did because of the space I had available, the restrictions laid upon me by my significant other and the goals I had in mind.
I'd love to see what your Omni setup would look like out in the room (especially a room as big as yours) as plotted by APL_TDA. The Demo version could do this, just use a screen grab to be able to save a picture of it. Download here...
Hope you're willing to play
Don't look at those graphs and expect to be close to it though. His setup probably exceeds most studio requirements.
In my opinion we can all learn together if we work together. And be open about what we do and why. At least that's why try to I write down the things I try, and even share what went wrong
I'll post the first 2 runs in my Omni thread http://www.diyaudio.com/forums/multi-way/303941-omnidirectional-work-progress-6.html#post5034322 as I'm not sure if the results are important to APL_TDA, or my Omni, or this thread. I suspect the discussion will center on the first two and not be pertinent to this thread. If I'm wrong I'm happy to continue it here
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