Actuarial Outpost
 
Go Back   Actuarial Outpost > Actuarial Discussion Forum > Software & Technology
FlashChat Actuarial Discussion Preliminary Exams CAS/SOA Exams Cyberchat Around the World Suggestions


Reply
 
Thread Tools Search this Thread Display Modes
  #671  
Old 10-18-2018, 12:25 PM
George Frankly's Avatar
George Frankly George Frankly is online now
Member
SOA AAA
 
Join Date: Aug 2011
Location: CO
Favorite beer: Sam Smith Oatmeal
Posts: 10,159
Default

Quote:
Originally Posted by Egghead View Post
I kept thinking about Floyd Toole's guidance that EQ should be avoided above the "transition frequency," especially as I've seen other authors with the same advice.

It turns out the Audyssey app on my iPhone can limit the range that gets EQ. I've tinkered with that until the response curve is essentially flat below 300 Hz (a common transition frequency for relatively small rooms) but no EQ above that. Sound is a little cleaner now, though in some ways I preferred the "enhanced" sound I was getting when I allowed it to EQ the full spectrum.

I am curious how important it is to have matched speakers for this approach. I would think the lack of EQ in the mid and treble ranges would cause the differences among speakers to be even more evident. I may hook up my old bookshelfs and play with it. But it's not really worth it. The five identical towers just sound so darn good.
I'm starting to think the same thing. A friend of mine has the Dirac EQ, and I've heard his setup a few times and played with turning it on and off, and honestly, I liked it better turned off.

If you measure a speaker's anechoic response, it's likely to be very flat. It's just not that hard to get a flat response with modern components. So the room is what's causing the response to wiggle. Maybe if you have some particular reflection you're trying to tame it makes sense to EQ, but I'm starting to think that a lot of heavy-handed EQ isn't where it's at. I think somehow the brain can 'decipher' what the room is doing with reflections and refractions, to some degree. I realize I'm waving my hands a lot in this explanation.

Recently, my friend got a new setup, JBL 15" woofers, some big 4" compression drivers (465Be), and small compression supertweeters (045Ti). And we ran the OmniMic, and just tweaked things slightly so the response looked more or less flat. And it blew me away. Since then he's made some minor tweaks, and then he let the Dirac do its thing, and he says it only made it worse. I need to go hear them again, they are just effortless with all the headroom. The 465Be is amazing, though not cheap.
Reply With Quote
  #672  
Old 10-18-2018, 01:10 PM
Egghead's Avatar
Egghead Egghead is offline
Member
SOA
 
Join Date: Aug 2006
Posts: 6,647
Default

Quote:
Originally Posted by George Frankly View Post
Bipolar surrounds were kind of the rage in the 90s. It's been a while since I heard any, I recall thinking they were nice, but not better than monopoles, on the whole.

Am I reading that right, that you tried running dual mains? Two left speakers, and two right speakers?
Sort of. I placed my surround speakers at +/- 80 degrees, so just slightly forward of being directly out to the sides. When I run music through the multi-channel stereo mode, it "upmixes" stereo. So it's basically dual mains, I guess. Now that I've got the timing correct between my speakers, the imaging is pretty darn awesome. Sounds that are hard-panned to side now sound like they're coming from in between the two speakers to that side. Sounds can still seem to be coming from the far speaker. Presumably, those are sounds that previously would have sounded like they were coming from outside the speakers in 2.1 mode. But I've got a really expansive soundstage, which helps singers in a duet, for example, to not sound like they're sitting in each other's laps.
Reply With Quote
  #673  
Old 10-18-2018, 01:22 PM
Egghead's Avatar
Egghead Egghead is offline
Member
SOA
 
Join Date: Aug 2006
Posts: 6,647
Default

Quote:
Originally Posted by George Frankly View Post
I'm starting to think the same thing. A friend of mine has the Dirac EQ, and I've heard his setup a few times and played with turning it on and off, and honestly, I liked it better turned off.
Audyssey XT was a big deterioration in the sound. Couldn't stand it. I like XT32 far better. It does much more EQ at the low end, and far less higher up.

Quote:
If you measure a speaker's anechoic response, it's likely to be very flat. It's just not that hard to get a flat response with modern components. So the room is what's causing the response to wiggle. Maybe if you have some particular reflection you're trying to tame it makes sense to EQ, but I'm starting to think that a lot of heavy-handed EQ isn't where it's at. I think somehow the brain can 'decipher' what the room is doing with reflections and refractions, to some degree. I realize I'm waving my hands a lot in this explanation.
Yeah, but you're doing the same hand-waving that some of the biggest researchers in the field are stuck doing. They have done tons of experiments showing that listeners (trained and untrained) do NOT like algorithms that flatten the measured frequency response at the listening position. Yet, tons of experiments show listeners DO like a flat frequency response as measured in an anechoic chamber. So it makes sense to assume that the human brain "hears through the room" and hears the speakers as they sound at the source, removing the effects of room reflections. Maybe there's more to it than that, but the results are extremely consistent in suggesting the preference for flat response measured anechoically. The ONE thing where EQ consistently helps is below the transition frequency. The most important thing is taming the peaks. There is more disagreement as to whether it helps to address the nulls through EQ (and physics limits the capability to do so, of course.)

Well, I'm oversimplifying a bit. People really do like having bass and treble controls, so it's a darn shame that those have been eliminated in audiophile products. There are just too many good reasons for people to need them:

* hearing loss as we get older hits the high frequencies more than the low
* some recordings are simply recorded too bright, especially from a few decades ago when they were likely compensating for bad speakers in consumer homes, and need to be tamed
Reply With Quote
  #674  
Old 10-18-2018, 01:26 PM
George Frankly's Avatar
George Frankly George Frankly is online now
Member
SOA AAA
 
Join Date: Aug 2011
Location: CO
Favorite beer: Sam Smith Oatmeal
Posts: 10,159
Default

Quote:
Originally Posted by Egghead View Post
Audyssey XT was a big deterioration in the sound. Couldn't stand it. I like XT32 far better. It does much more EQ at the low end, and far less higher up.

Yeah, but you're doing the same hand-waving that some of the biggest researchers in the field are stuck doing. They have done tons of experiments showing that listeners (trained and untrained) do NOT like algorithms that flatten the measured frequency response at the listening position. Yet, tons of experiments show listeners DO like a flat frequency response as measured in an anechoic chamber. So it makes sense to assume that the human brain "hears through the room" and hears the speakers as they sound at the source, removing the effects of room reflections. Maybe there's more to it than that, but the results are extremely consistent in suggesting the preference for flat response measured anechoically. The ONE thing where EQ consistently helps is below the transition frequency. The most important thing is taming the peaks. There is more disagreement as to whether it helps to address the nulls through EQ (and physics limits the capability to do so, of course.)

Well, I'm oversimplifying a bit. People really do like having bass and treble controls, so it's a darn shame that those have been eliminated in audiophile products. There are just too many good reasons for people to need them:

* hearing loss as we get older hits the high frequencies more than the low
* some recordings are simply recorded too bright, especially from a few decades ago when they were likely compensating for bad speakers in consumer homes, and need to be tamed
Interesting, my admittedly un-scientific experiments agree with what you're saying.

And I agree that the old bass/treble knobs were nice. They were simple, and effective. Many receivers have a built-in EQ but it takes six clicks to get there.
Reply With Quote
  #675  
Old 10-18-2018, 01:28 PM
Egghead's Avatar
Egghead Egghead is offline
Member
SOA
 
Join Date: Aug 2006
Posts: 6,647
Default

Quote:
Originally Posted by George Frankly View Post
Recently, my friend got a new setup, JBL 15" woofers, some big 4" compression drivers (465Be), and small compression supertweeters (045Ti). And we ran the OmniMic, and just tweaked things slightly so the response looked more or less flat. And it blew me away. Since then he's made some minor tweaks, and then he let the Dirac do its thing, and he says it only made it worse. I need to go hear them again, they are just effortless with all the headroom. The 465Be is amazing, though not cheap.
I've decided I'm not going to allow myself to listen to such systems. Not any time soon. I don't want to know that there is something that sounds better than what I have put together. I know that there have to be better-sounding systems than mine, but I've not heard one. If I did, I might get the urge to spend more ridiculous money.
Reply With Quote
  #676  
Old 10-18-2018, 01:46 PM
Egghead's Avatar
Egghead Egghead is offline
Member
SOA
 
Join Date: Aug 2006
Posts: 6,647
Default

It's funny: I've been continuing to read through the Floyd book. Shortly after I found that I like having my surround speakers at roughly 90 degrees, I got to this part of his book:

Quote:
The important message in these data is that the placement of loudspeakers may be as important as the number, and placement more to the side is advantageous. Sounds arriving from the rear are extremely rare in the standard repertoire of music, but the need for a credible spatial impression is common. Ironically, a 1971 publication entitled Subjective Assessment of Multichannel Reproduction (Nakayama et al., 1971) showed that listeners preferred surround loudspeakers positioned to the sides, compared to ones placed behind, awarding subjective rating scores that were two to four times higher. It seems that nobody with any influence read it.
Reply With Quote
  #677  
Old 10-18-2018, 01:49 PM
George Frankly's Avatar
George Frankly George Frankly is online now
Member
SOA AAA
 
Join Date: Aug 2011
Location: CO
Favorite beer: Sam Smith Oatmeal
Posts: 10,159
Default

Quote:
Originally Posted by Egghead View Post
It's funny: I've been continuing to read through the Floyd book. Shortly after I found that I like having my surround speakers at roughly 90 degrees, I got to this part of his book:
LOL at the last sentence.
Reply With Quote
  #678  
Old 10-18-2018, 01:52 PM
George Frankly's Avatar
George Frankly George Frankly is online now
Member
SOA AAA
 
Join Date: Aug 2011
Location: CO
Favorite beer: Sam Smith Oatmeal
Posts: 10,159
Default

Quote:
Originally Posted by Egghead View Post
I've decided I'm not going to allow myself to listen to such systems. Not any time soon. I don't want to know that there is something that sounds better than what I have put together. I know that there have to be better-sounding systems than mine, but I've not heard one. If I did, I might get the urge to spend more ridiculous money.
I used to worry about that. Often, I find that I like other speakers more for (say) vocals compared to mine, but less for rock or whatever. So it's good to compare and contrast. There are definitely better systems out there than mine, and I do enjoy hearing them, but they often cost a LOT more. And I've come to terms with 'I could upgrade, but to get any significant improvement will cost way more than I'm willing to spend.'
Reply With Quote
  #679  
Old 10-18-2018, 02:13 PM
Egghead's Avatar
Egghead Egghead is offline
Member
SOA
 
Join Date: Aug 2006
Posts: 6,647
Default

Floyd then goes on to share lots of research that's been done since that 1971 one (that nobody read ). The ideal for movie listening seems to be Dolby's advice for 5.1 (with the surrounds a little behind the listener, but mostly to the side.) For music listening, listeners tend to prefer the surrounds to the side, and maybe somewhat forward. They have come up with an objective measure that correlates strongly with the sense of "spaciousness" known as Apparent Source Width (a subjective measure). The objective measure is known as Interaural Cross-Correlation Coefficient (IACC).

Quote:
The more different the sounds are at the two ears, at certain frequencies and delays, the greater the sense of these spatial descriptors [ASW, image broadening, spaciousness and envelopment.] The locations of the ears then determine that sounds arriving from different directions generate different amounts of IACC and perceived ASW. Sounds from the sides are most effective; those from front and back, least effective.

...

Here it is necessary to emphasize that reflections occurring in small rooms cannot alone generate a sense of true envelopment. Envelopment requires delays (more than about 80 ms) that can only be supplied by recorded signals reproduced through multiple loudspeakers. Additional room reflections of those greatly delayed signals may enhance the impression, but the initial delay and the appropriate directions must be provided in the recorded sound and in the arrangement of playback loudspeakers.
He then goes on to cite some pretty cool studies, where they found that a circle of evenly spaced speakers (24 of them!) could do a remarkably good job of recreating the experience of listening to music in a music hall (using 24 discrete microphones). Then the researchers tried different placement and numbers of speakers to see what the minimum needed was to get awfully close to reproducing it, and they landed on 4 or 5. The best with 5 speakers is the placement of:

* straight ahead
* front mains at 30 degrees off center
* rears at 120 degrees off center (so 30 degrees behind straight out to the sides)

But there were a number of arrangements that used only 4 speakers, among them a number with NONE of the speakers placed behind the listener, that were judged just as highly.
Reply With Quote
  #680  
Old 10-23-2018, 10:39 PM
Egghead's Avatar
Egghead Egghead is offline
Member
SOA
 
Join Date: Aug 2006
Posts: 6,647
Default

Got my 2nd sub today. And at first ... I was kind of bummed. It sucked out a bunch of my bass. I thought, "How can this be? Two subs is supposed to be better, more even!"

Then I realized I had the phase switch on different settings for each sub. Much better results after flipping one!

Like George Frankly and others suggested, the main benefit of dual subs is more even bass in more chairs around the room.

An interesting side benefit: less rattling of the walls and windows. That's handy, because I've often found the rattles pretty distracting, especially from movies.

Last edited by Egghead; 10-24-2018 at 07:12 AM..
Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


All times are GMT -4. The time now is 12:24 PM.


Powered by vBulletin®
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
*PLEASE NOTE: Posts are not checked for accuracy, and do not
represent the views of the Actuarial Outpost or its sponsors.
Page generated in 0.56786 seconds with 10 queries