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REW Measurements for Room Correction Systems (YPAO, ARC, Audyssey etc) - Page 3

post #61 of 163
Quote:
Originally Posted by Nick @ Anthem View Post

markus767, thanks for the link to already-referenced info but how does this cover a case where each of four subs must stay in the corners?.

Why is it all of a sudden about a specific case (4 subs in corners)? That's not where the discussion started. We even didn't talk about a specific number of subs.

Gear mentioned in this thread:

post #62 of 163
^ It is not all of a sudden about a specific case. The general guideline I've been mentioning does not exclude anything in the method that you reference, which is itself a specific case since it specifies the number of subs and more or less where to position them.

All this because someone missed the part where I said "start with..." so many posts ago while fixating on one setup method as if it's the only one in the whole world.
post #63 of 163
Quote:
Originally Posted by Nick @ Anthem View Post

^ It is not all of a sudden about a specific case. The general guideline I've been mentioning does not exclude anything in the method that you reference, which is itself a specific case since it specifies the number of subs and more or less where to position them.

The guidelines you've mentioned do exclude the Geddes method because that method neither uses level matched subs that are optimized together nor does it require a specific number of subs or specific locations.
Quote:
Originally Posted by Nick @ Anthem View Post

All this because someone missed the part where I said "start with..." so many posts ago while fixating on one setup method as if it's the only one in the whole world.

My point was that "start with a number of matched subs and apply EQ to the cluster" is statistically as good as "start with a number of unmatched subs and apply EQ to the cluster". If the placement is random.
post #64 of 163
Quote:
Originally Posted by DS-21 View Post

Quote:
Originally Posted by J_Palmer_Cass View Post

Do you expect any company to do custom engineering for you at no charge?

I’m not sure what you mean here by “custom engineering.” All I asked them to do is tell me how their bloody box works. For example, “don’t use the mixer to fold the sub channel back into the mains, because the end result will be x dB hot” or “if you tick the box in the ARC software (I don’t have my Mac in front of me to put in cripple mode and look at exactly how ARC words things) then the main channels will get all of the information in those channels, and the sub will only get LFE information.”

Is that “custom engineering” in your book?


When it comes to bass management, I don't know of any company that discloses the details on how they do things internal to the unit. Now if you want to make the unit do something it was not designed to do and you want someone else to figure out how to do it, then that would be custom engineering. How to connect multiple subwoofers in a non standard manner is your problem as is speaker selection.

What I had to do was take 5.1 channel test signals, and then document how bass mangement works in my unit (Sony AVR). Every time I change a speaker size in the AVR (small/large/none), then bass management changes. Bass redirection is very tricky. Unless you document your unit on your own, you will never figure it out.



Quote:
Originally Posted by DS-21 View Post

Quote:
Originally Posted by J_Palmer_Cass View Post

What is this special bass management scheme that you thought up?

Basically Wayne Parham's riff on the Geddes method, with "flanking subs" that play higher to smooth out floor bounce ("Allison effect"), and other subs placed randomly in the room to smooth out room modes. I think the case for such an arrangement will be clear by looking at the listening-position measurements I took of three loudspeakers at my right speaker position (KEF Q100, Soundfield Audio Monitor 1, Tannoy System 8 NFM II) here, using the Anthem box's single best feature, "Quick Measure." Room issues clearly go up to around 300Hz in this room, with this speaker placement. And this speaker placement is the only one I can feasibly effect in this room. (I experimented with dipole midbasses, but they just dropped like a stone from 300Hz down.)

So, five subs total:
Flanking subs: stands for the mains that are about 32" tall and 60L total volume, closed box, with the woofer firing on the inside-back (like the old NHT towers). Inside-back corner of the cabinets would be flush against the wall, though at an acute angle because of the toe-in. (Fiancee prefers the look of rectangular speakers toed-in such that they cross ahead of the listening position to NHT-style angled baffles, so fair enough. Also, that way LCR can be identical.) These subs blended as high as they need to be, with no highpass on their bottom end. The flanking subs will most likely use my Aurasound NS12-794-4A's, as they're good to way higher than I'd use them (800Hz-1kHz is their usable top end, amazingly enough) and they have very good performance (basically no inductance due to the big copper sleeves on their motors, 3" diameter underhung voicecoils, ~15mm of underhung xmax). I also have a pair of JBL 15's that were designed for the original Revel Ultima subs that I may use instead. They're overhung with 4" diameter voicecoils. Both the NS12's and the JBL/Revel's work well in 60L closed boxes. But for a variety of reasons I'm leaning to the Auras.

Other subs: M-Design Eleganza Godfather (Aurasound NS15-992-4A + 1kW Class G amp) in the front left corner, 65L closed box with Aurasound NS12-794-4A on the right side near the back, 15L closed box with Aurasound NS10-794-4A on top of a tall bookshelf on the back wall.

My question to Anthem tech support arose in the first place because, per the big MRX thread, the Anthem AVR’s simply discard LFE information when you set it to “no sub.” Otherwise one could just set the MRX to no sub and use external processing to properly sweep mains with subs and set up the system. Also, ARC only allows a sub crossover up to 150Hz with fairly steep slopes, so I'm skeptical I'll just be able to connect the five subs through the LFE channel and use the onboard crossover straight up. Though I will try that first, if only to see if simple can work.


The LFE discard when no sub is selected is problematical. Does LFE discard mean discard the .1 LFE channel, or does it mean discard the LFE channel plus all redirected bass signals? The term LFE is used in various ways on this forum.

I use large NHT speakers (R, L, RS, LS) with a small NHT center, and I send the .1 LFE channel plus RB to the R & L mains using "standard" bass management (Large R &L speakers, Small other speakers set in AVR). If the LFE was dropped by the AVR, I could get around it but then I would have a complicated mess on my hands (similar to your problem). The dedicated subwoofer covers from 50 Hz on down for all channels.

Note that I have tried many different bass management setups with the same AVR and speakers (and optional external crossovers). Various subwoofer combinations (AKA locations - 4 subwoofers) were tried. The less complicated & simpler setups performed the best.

Sounds to me like you have to design your own custom bass mangement scheme.
post #65 of 163
Quote:
Originally Posted by markus767 View Post

Quote:
Originally Posted by Nick @ Anthem View Post

^ It is not all of a sudden about a specific case. The general guideline I've been mentioning does not exclude anything in the method that you reference, which is itself a specific case since it specifies the number of subs and more or less where to position them.

The guidelines you've mentioned do exclude the Geddes method because that method neither uses level matched subs that are optimized together nor does it require a specific number of subs or specific locations.


The Geddes scheme (and other) is a custom setup, meaning non standard. If you don't know what you are doing with any custom setup, then don't do it or spend the time to figure it out. I don't think that any AVR / processor manufacturer is in the subwoofer consulting business.

Does any equipment have a Geddes emblem printed on it (like DD, DTS, etc.)? The Geddes output that I use is not a standard output that is available in an AVR.
post #66 of 163
Quote:
Originally Posted by J_Palmer_Cass View Post

When it comes to bass management, I don't know of any company that discloses the details on how they do things internal to the unit.

No car manufacturer discloses how turning the steering wheel makes a car change direction. Bass management really isn't rocket science and apart from some weird individual cases (like Emotiva UMC-1), the signal flow is and should be the same in every AVR:

post #67 of 163
Quote:
Originally Posted by J_Palmer_Cass View Post

Does LFE discard mean discard the .1 LFE channel, or does it mean discard the LFE channel plus all redirected bass signals? The term LFE is used in various ways on this forum.

.1 only. It has to do with available voltage swing in the main channels since LFE requires a 10 dB boost. Not that unusual, and meets licensing requirements. Redirected bass still goes to the fronts.

Proper terminology: LFE = .1 channel, Subwoofer Channel = LFE + redirected bass.
post #68 of 163
Quote:
Originally Posted by markus767 View Post

My point was that "start with a number of matched subs and apply EQ to the cluster" is statistically as good as "start with a number of unmatched subs and apply EQ to the cluster". If the placement is random.

My point is about having a frame of reference. Statistically, this helps when someone contacts our tech support, a common practice among ARC users. Look at how many post their graphs in the Anthem threads, keeping in mind that AVSers are a small part of the customer base.

You still haven't indicated how you would handle the same situation, and replying with a link to the Geddes method is not the answer.
post #69 of 163
Quote:
Originally Posted by markus767 View Post

Bass management really isn't rocket science and apart from some weird individual cases (like Emotiva UMC-1), the signal flow is and should be the same in every AVR:

You are making several assumptions starting with overlooking the fact that licensee information manuals provide several options.

Bass management is not the same in all AVRs, and especially not in hi-end AVPs. Block diagrams may fit two or three molds but the filtering and delay algorithms vary in several other ways that affect sound quality, and they're usually proprietary.
post #70 of 163
Quote:
Originally Posted by markus767 View Post

Quote:
Originally Posted by J_Palmer_Cass View Post

When it comes to bass management, I don't know of any company that discloses the details on how they do things internal to the unit.

No car manufacturer discloses how turning the steering wheel makes a car change direction. Bass management really isn't rocket science and apart from some weird individual cases (like Emotiva UMC-1), the signal flow is and should be the same in every AVR:




That generic bass managementn diagram only applies when all speakers are set to small.

If you set any speaker to large, it does not apply!
post #71 of 163
Quote:
Originally Posted by Nick @ Anthem View Post

Quote:
Originally Posted by J_Palmer_Cass View Post

Does LFE discard mean discard the .1 LFE channel, or does it mean discard the LFE channel plus all redirected bass signals? The term LFE is used in various ways on this forum.

.1 only. It has to do with available voltage swing in the main channels since LFE requires a 10 dB boost. Not that unusual, and meets licensing requirements. Redirected bass still goes to the fronts.

Proper terminology: LFE = .1 channel, Subwoofer Channel = LFE + redirected bass.



I agree with your terminology. Some people just tend to call the subwoofer output the LFE output.

As far as dropping the LFE channel when the subwoofer output is set to None, that is very unusual in a prepro or AVR. On a historic basis, dropping the .1 LFE was only allowed in equipment like a DVD / Bluray player and the like when you downmix to 2-channel
post #72 of 163
^ Not to deflect the topic, and of course there are esoteric rare exceptions but the chance of a "full-range" passive front's LF performance outperforming that of a decent powered sub is practically zero.

So for the other 99.9% I say just use a real sub, even if it's a main speaker with an RCA/XLR input for its woofer section. Powered subs are available in many shapes and sizes and there's at least one room-correctable 8 inch model on the market that plays down to 23 Hz (-3 dB in-room). In other words, excuses about lack of space or whether the AVR has room correction at all need not apply, and sorry for the thinly veiled infomercial but it's a fact.
post #73 of 163
Quote:
Originally Posted by Nick @ Anthem View Post

My point is about having a frame of reference. Statistically, this helps when someone contacts our tech support, a common practice among ARC users.

What is "this"? You obviously have something specific in your mind that you haven't really articulated yet. You made a disputable general statement. Putting subwoofers randomly in a room and comparing a level-matched configuration to an unmatched configuration will statistically show no significant difference because every room is different. You could also say that people should start with gain-matched subs. This will also "work" as a general guideline. Or match subs to their max SPL capabilities. The latter would even have a secondary positive effect.
Quote:
Originally Posted by Nick @ Anthem View Post

Look at how many post their graphs in the Anthem threads, keeping in mind that AVSers are a small part of the customer base.
You still haven't indicated how you would handle the same situation, and replying with a link to the Geddes method is not the answer.

I replied with the link because you asked for it.
post #74 of 163
Quote:
Originally Posted by Nick @ Anthem View Post

You are making several assumptions starting with overlooking the fact that licensee information manuals provide several options.

What specific "licensee information manuals" are you talking about?
Quote:
Originally Posted by Nick @ Anthem View Post

Bass management is not the same in all AVRs, and especially not in hi-end AVPs. Block diagrams may fit two or three molds but the filtering and delay algorithms vary in several other ways that affect sound quality, and they're usually proprietary.

Probably 99% of all AVRs have the signal flow implemented like shown in the picture. Of course there are differences in how filters and delays are implemented but that doesn't change the basic principle of bass redirection.
post #75 of 163
Quote:
Originally Posted by J_Palmer_Cass View Post

That generic bass managementn diagram only applies when all speakers are set to small.
If you set any speaker to large, it does not apply!

I know, so what? That case isn't rocket science either and works the same across most AVRs. But why would anybody with a sub (or better: multiple subs) set their speakers to anything other than small?
Edited by markus767 - 11/2/12 at 9:32am
post #76 of 163
Pretty funny how threads always disintegrate into bickering...in the beginning the idea behind this thread was pretty interesting...
post #77 of 163
Question for those of you that know YPAO.

I'm I correct in understanding YPAO basically....

o Identifies the distance to each speaker for setting delays for time alignment;

o Identifies speaker size based on low end frequency cut-off;

o Identifies prominent nodes resulting from speaker/room acoustics and sets parametric filters to tailor the overall frequency performance;

o Sets the channel levels to balance the various speaker outputs for performance around a given position.

o and does little with sub management other than permitting one to chose a cut-off frequency

Have I missed or incorrectly understood some aspect of YPAO?

Thanks,
post #78 of 163
Quote:
Originally Posted by markus767 View Post

What is "this"? You obviously have something specific in your mind that you haven't really articulated yet.

The frame of reference. There are only so many hours in the day and I'm not here to write an essay, only to get the basic message across. Imagine looking two sets of measurements taken in the same room. It helps to know that one was made with each sub set to a known SPL relative to the listening position while the other was with one of the subs reduced by a known amount. And so on with subsequent trials. This is how an effect becomes associated with a variable, and the path to optimizing the setup begins. Every report is treated case by case - it's the only practical thing to do, especially when we're not on-site and things can go in any direction.

Please keep in mind that I was replying to an ARC user before your intervention. If it's not too much to ask, let's close this tiresome side topic about when to balance what since it's not helping anyone, and respectfully return the discussion as was intended by the thread starter. I have no desire to remain in it otherwise. Thank you.
post #79 of 163
Nick

I just tried to offer a broader view at low frequency reproduction. No room correction system that is currently available will result in the best possible low frequency response within a given room. While technically feasible, such an approach would require an enormous amount of measurements.

You replied to DS-21 - to my knowledge he's not an ARC user. This is where I "intervened". I agree that our discussion is off-topic and I'm fine with closing this side topic.
post #80 of 163
Quote:
Originally Posted by markus767 View Post

Nick
I just tried to offer a broader view at low frequency reproduction. No room correction system that is currently available will result in the best possible low frequency response within a given room. While technically feasible, such an approach would require an enormous amount of measurements.
You replied to DS-21 - to my knowledge he's not an ARC user. This is where I "intervened". I agree that our discussion is off-topic and I'm fine with closing this side topic.

DS-21 is an ARC user, he has an MRX 300.
John
post #81 of 163
Good to know and even more interesting that he doesn't agree with Nick's recommendation.
post #82 of 163
Quote:
Originally Posted by markus767 View Post

Quote:
Originally Posted by J_Palmer_Cass View Post

That generic bass managementn diagram only applies when all speakers are set to small.
If you set any speaker to large, it does not apply!

I know, so what? That case isn't rocket science either and works the same across most AVRs. But why would anybody with a sub (or better: multiple subs) set their speakers to anything other than small?


Why? Maybe because they know what they are doing if they have "large" speakers. Perhaps you can ask DS-21 why he needs to use some large speaker settings. I pretty much know what DS-21 is trying to do, but he can not do what he wants to do easily with the bass management of his unit.

I have a sub, and I run my R & L mains as large (others small). LFE is sent the the R & L mains. Stacked subwoofer(s) (3 units from floor to about 48" high) are in use at a single corner location and cover frequencies below a nominal 50 Hz. Stereo bass above a nominal 50 Hz, mono bass below. No problems at all.

Since you claim to be a Geddes expert, perhaps you can explain why Geddes sets his mains to large. In addition, where does Geddes place his main subwoofer and what frequency range does it cover?
post #83 of 163
Stereo bass in acoustically small rooms? I don't see how this could ever work. It's a specific propery of acoustically small rooms to heavily distort directional information at low frequencies because wavelengths are much larger than room dimensions (10Hz = 34m, 50Hz = 7m, 100Hz = 3.4m).

Besides that you would need to have L, R, sub + L, sub + R and sub + L + R provide the same flat low frequency response. Very unlikely that this is going to happen. Did you ever measure all possible combinations in your setup?

That's why bass redirection is used - the bass signal is always radiated from the same number and location of subs. Now one needs to optimize only one single configuration which behaves uniformly, no matter if the bass signal is panned across channels or is mixed only to LFE, L, R or whatever channel.

I don't "claim to be a Geddes expert". To my knowledge he doesn't recommend setting the mains to large anymore because of the problems mentioned above. It's probably easier to ask him yourself as he is pretty accessible: http://gedlee.com
post #84 of 163
Quote:
Originally Posted by markus767 View Post

Stereo bass in acoustically small rooms? I don't see how this could ever work. It's a specific propery of acoustically small rooms to heavily distort directional information at low frequencies because wavelengths are much larger than room dimensions (10Hz = 34m, 50Hz = 7m, 100Hz = 3.4m).

Besides that you would need to have L, R, sub + L, sub + R and sub + L + R provide the same flat low frequency response. Very unlikely that this is going to happen. Did you ever measure all possible combinations in your setup?

That's why bass redirection is used - the bass signal is always radiated from the same number and location of subs. Now one needs to optimize only one single configuration which behaves uniformly, no matter if the bass signal is panned across channels or is mixed only to LFE, L, R or whatever channel.


You have your blinders on. You are obsessed with "measured flat" single seat mono bass.

Who says that I do not use bass redirection? Not true, so that non-issue can be tossed out right away.

Who says that I play the R and L speakers without a subwoofer? I can do that by hitting the analog direct or 2 channel stereo function in the AVR, but those features disable bass management regardless of the settings (AKA no subwoofer at all). No different than your setup would behave under the same circumstances (AKA 2 channel - no BM, no SW).

Now have I ever measured "all possible speaker combinations"? Not "all possible" speaker combinations, but have you done so? I have measured main speakers (all 5) and subwoofer combinations (and Geddes type of add on speakers). I have measured all adjacent pairs of speakers to see what the speaker to speaker interactions were. Most pans are one speaker to the next speaker, so I looked at that and fine tuned my settings a bit.

For some reason you left out the center and surround speakers interaction with your subwoofers (and other speakers). Have you ever made those measurements?

To keep things simple about "stereo bass" (AKA multi channel bass), think about your crossover frequency. What crossover frequency do you use, and why do you use it? At what frequency area does mono bass change to stereo bass with your settings? How does that crossover frequency relate to hearing "stereo bass" effects? Notice that I did not say "stereo subwoofers".

As far as bass redirection is concerned, have you ever looked into the bass redirection schemes that are used in a unit like a Lexicon MC-12? Sanjay clued me in on that type of BM years ago, and the bass redirection sheme that they use is very interesting. I do not use the all small speaker bass redirection scheme that you prefer to use.



Quote:
Originally Posted by markus767 View Post


I don't "claim to be a Geddes expert". To my knowledge he doesn't recommend setting the mains to large anymore because of the problems mentioned above. It's probably easier to ask him yourself as he is pretty accessible: http://gedlee.com


No thank you. I learned the basic Geddes concepts from Geddes on the Geddes subwoofer thread here on AVS. I have no need to copy what he does, mainly because his methods are / were half baked. He prefers to do everything the hard way.
Edited by J_Palmer_Cass - 11/3/12 at 5:40am
post #85 of 163
Quote:
Originally Posted by J_Palmer_Cass View Post

You have your blinders on. You are obsessed with "measured flat" single seat mono bass.

I'm "obsessed" with good low frequency reproduction, yes, and I don't ignore acoustic facts. No need for getting personal J_Palmer_Cass. This discussion will be over if you can't stick to facts and keep getting personal.

The frequency response at my listening position (red) and 2ft (!) to the left and the right looks like this (blue is the magnitude response of the MultEQ XT32 filter):



That's 3 seats with virtually no difference in performance.

Acoustically small rooms don't support directional low frequency information well. They distort them. You'll find pressure gradients caused by the room's modal pattern that will result in directional cues that don't match the directional information in the recording. There's no way around it. That behavior is specific to small spaces. So if we can't preserve spatial cues then we could at least try to aim for flat frequency response and low modal ringing. This can be done with multiple subs and absorption (active or passive).
Or do you seriously doubt that flat frequency response and low modal ringing is a desirable goal in sound reproduction?
Quote:
Originally Posted by J_Palmer_Cass View Post

Who says that I do not use bass redirection? Not true, so that non-issue can be tossed out right away.

This is what you've said: "I have a sub, and I run my R & L mains as large (others small)."
Does your AVR handle this in any other way than most AVRs?
Quote:
Originally Posted by J_Palmer_Cass View Post

Who says that I play the R and L speakers without a subwoofer? I can do that by hitting the analog direct or 2 channel stereo function in the AVR, but those features disable bass management regardless of the settings (AKA no subwoofer at all). No different than your setup would behave under the same circumstances (AKA 2 channel - no BM, no SW).

Don't follow, you would need to describe your setup in more detail.
Quote:
Originally Posted by J_Palmer_Cass View Post

Now have I ever measured all speaker combinations? Yes, have you? I also measured all adjacent pairs of speakers to see what the speaker to speaker interactions were. Most pans are one speaker to the next speaker, so I looked at that and fine tuned my settings a bit.

Would you mind showing that data? Did you also compare to "normal" bass management? If not then no statement can be made about which approach is better.

Not sure why you're asking if I have measured speaker combinations. But yes, I do measure quite a lot and I also post them.
Quote:
Originally Posted by J_Palmer_Cass View Post

For some reason you left out the center and surround speakers interaction with your subwoofers (and other speakers). Have you ever made those measurements?

Yes, you would have to optimize all possible channel combinations if you want to have a perfect result. But this makes it even less likely that your approach will work.

I'm not sure why you keep asking if I have made such measurements. I've seen a lot of in-room measurements and simply by looking at them it is obvious that your approach can only yield very compromised results. It's hard enough to find the best locations for multiple subs that are driven by a monophonic signal but you want to optimize any speaker combination without even having the freedom of relocating any speaker besides the sub? That's simply impossible.
Quote:
Originally Posted by J_Palmer_Cass View Post

To keep things simple about "stereo bass" (AKA multi channel bass), think about your crossover frequency. What crossover frequency do you use, and why do you use it? At what frequency area does mono bass change to stereo bass with your settings? How does that crossover frequency relate to hearing "stereo bass" effects? Notice that I did not say "stereo subwoofers".

I've already described the problem of reproducing low frequency spatial cues in acoustically small rooms. You can't have large room acoustics in a small room with a standard multichannel configuration like 5.1 or 7.1.
Quote:
Originally Posted by J_Palmer_Cass View Post

As far as bass redirection is concerned, have you ever looked into the bass redirection scemes that are used in a unit like a Lexicon MC-12? Sanjay clued me in on that type of BM years ago. I do not use the all small speaker bass redirection scheme that you prefer to use.

That's one of the devices I was talking about earlier that handle things differently than most AVRs.
Quote:
Originally Posted by J_Palmer_Cass View Post

No thank you. I learned the basic Geddes concepts from Geddes on the Geddes subwoofer thread here on AVS. I have no need to copy what he does, mainly because his methods are / were half baked. He prefers to do everything the hard way.

One must have a very strong educational background in acoustics to make such claims.
post #86 of 163
Markus, you just do not have a good handle on bass management and bass redirection. Depending on settings, bass may be sent to the subwoofer, or it may be sent to other large speakers, or it may be sent both. Different speaker size settings change bass redirection and mix levels in addition to appying the applicable low and high pass filters. The only easy to understand combinations are all large speakers with subwoofer, and all small speakers with subwoofer. All other speaker size combinations do not follow obvious bass / lfe routing.

For an example, if I select certain speaker size combinations in my unit, the .1 LFE channel is redirected to every speaker except for the center.

My R & L mains are indeed set to large. That means an electrical HP filter is not applied to the main speakers (same as Geddes). That does not mean the subwoofer is not used or can not be used or will not be used or the R & L speakers are not crossed over to a subwoofer. Setting the R & L mains to large means that bass is not redirected and mixed the same way as the all small plus subwoofer redirection scheme.

If I want to play the R & L mains in a 2 channel mode (AKA not 2.1), I use the analog direct or 2-channel "stereo" mode in the AVR. Analog Direct only works on analog inputs. No analog/digital conversions all the way to the speakers. The 2-Channel Stereo mode works in digital and analog (AKA allows for EQ), but bass mangement is disabled. You know, like 2 channel stereo units running speakers the "old fashioned way".

I don't throw a lot of speakers around the room like some prefer to do for whatever reason they chose to do so. I do redirect bass via bass management to existing multiple "large" speakers so the bass couples to the room in an appropriate manner.

I noticed you skipped over the frequency that you crossover from your mains to your subwoofer. I also notice that you skipped over the frequency area where your can hear a transition from mono bass to stereo bass with your specific setup. A vague reference to "low frequencies" is useless. Same as the often used vague claim that the best position to place your main speakers in not the best position to reproduce bass. Bass covers from about 180 Hz on down, so that covers a lot of ground. You can justify any crossover frequency in that "bass range" and still be correct.

My claim about Geddes is not related to acoustics. It is related to Geddes use of "Geddes custom bass management" as doing things the hard way.
Edited by J_Palmer_Cass - 11/3/12 at 8:10am
post #87 of 163
Quote:
Originally Posted by J_Palmer_Cass View Post

Markus, you just do not have a good handle on bass management and bass redirection. Depending on settings, bass may be sent to the subwoofer, or it may be sent to other large speakers, or it may be sent both. Different speaker size settings change bass redirection and mix levels in addition to appying the applicable low and high pass filters. The only easy to understand combinations are all large speakers with subwoofer, and all small speakers with subwoofer. All other speaker size combinations do not follow obvious bass / lfe routing.
For an example, if I select certain speaker size combinations in my unit, the .1 LFE channel is redirected to every speaker except for the center.
My R & L mains are indeed set to large. That means an electrical HP filter is not applied to the main speakers (same as Geddes). That does not mean the subwoofer is not used or can not be used or will not be used or is not crossed over to a subwoofer. Setting the R & L mains to large means that bass is not redirected and mixed the same way as the all small plus subwoofer redirection scheme.

What makes you think that I "do not have a good handle on bass management and bass redirection"?? Routing schemes in AVRs are rather trivial and pretty uniform across most brands.

If you set a speaker to large then no high pass is applied to that channel and the signal doesn't get routed to the subwoofer mix bus. If you set all speakers to large then only the LFE is routed to the sub out. Pretty standard behavior and by the way easily deducible from the routing scheme I had posted earlier.
Quote:
Originally Posted by J_Palmer_Cass View Post

If I want to play the R & L mains in a 2 channel mode (AKA not 2.1), I use the analog direct or 2-channel "stereo" mode in the AVR. Analog Direct only works on analog inputs. No analog/digital conversions all the way to the speakers. The 2-Channel Stereo mode works in digital and analog (AKA allows for EQ), but bass mangement is disabled. You know, like 2 channel stereo units running speakers the "old fashioned way".

If you need to have an "old fashioned" two speaker stereo setup then be it. I just don't see the benefit.
Quote:
Originally Posted by J_Palmer_Cass View Post

I don't throw a lot of speakers around the room like some prefer to do for whatever reason they chose to do so. I do redirect bass via bass management to existing multiple "large" speakers so the bass couples to the room in an appropriate manner.

If you would take the time trying to understand why "some prefer to throw a lot of speakers around the room" then you would understand why setting all speakers to large can't provide the same quality as an optimized multiple subwoofer configuration.
See
http://www.aes.org/e-lib/download.cfm?ID=13686&name=harman
http://www.aes.org/e-lib/download.cfm?ID=13680&name=harman
There are many other papers (see AES).
Quote:
Originally Posted by J_Palmer_Cass View Post

I noticed you skipped over the frequency that you crossover from your mains to your subwoofer. I also notice that you skipped over the frequency area where your can hear a transition from mono bass to stereo bass with your specific setup.

I did not "skip over" anything. You refuse to acknowledge basic acoustic and psychoacoustic principles. Just because we can get directional information from low frequency sounds in a free field or a large room doesn't mean it is preserved when reproduced in an acoustically small room. Read Everest, read Toole, even reading David Griesinger (which is a proponent of stereo bass) will help.
Quote:
Originally Posted by J_Palmer_Cass View Post

My claim about Geddes is not related to acoustics. It is related to Geddes use of "Geddes custom bass management" as doing things the hard way.

Doesn't matter if something is easy to do or hard to do, what matters is the result.

What are your results? If I remember correctly you only have a SPL meter for acoustic measurements?
Edited by markus767 - 11/3/12 at 7:46am
post #88 of 163
Quote:
Originally Posted by markus767 View Post

Quote:
Originally Posted by J_Palmer_Cass View Post

Markus, you just do not have a good handle on bass management and bass redirection. Depending on settings, bass may be sent to the subwoofer, or it may be sent to other large speakers, or it may be sent both. Different speaker size settings change bass redirection and mix levels in addition to appying the applicable low and high pass filters. The only easy to understand combinations are all large speakers with subwoofer, and all small speakers with subwoofer. All other speaker size combinations do not follow obvious bass / lfe routing.
For an example, if I select certain speaker size combinations in my unit, the .1 LFE channel is redirected to every speaker except for the center.
My R & L mains are indeed set to large. That means an electrical HP filter is not applied to the main speakers (same as Geddes). That does not mean the subwoofer is not used or can not be used or will not be used or is not crossed over to a subwoofer. Setting the R & L mains to large means that bass is not redirected and mixed the same way as the all small plus subwoofer redirection scheme.

What makes you think that I "do not have a good handle on bass management and bass redirection"?? Routing schemes in AVRs are rather trivial and pretty uniform across most brands.

If you set a speaker to large then no high pass is applied to that channel and the signal doesn't get routed to the subwoofer mix bus. If you set all speakers to large then only the LFE is routed to the sub out. Pretty standard behavior and by the way easily deducible from the routing scheme I had posted earlier.


What makes me know that you do not have a good handle on bass management? Maybe because of nearly everything that you write about the issue.

Here is a trival bass management question.

Bass mangement speaker settings: R & L mains set to large, Center set to small 80 Hz crossover, and Surrrounds set to small 50 Hz crossover, Subwoofer set to ON (or OFF if that pleases you).

Bass management question: Where is the Center channel bass below 80 Hz redirected to?



Quote:
Originally Posted by markus767 View Post

Quote:
Originally Posted by J_Palmer_Cass View Post

I don't throw a lot of speakers around the room like some prefer to do for whatever reason they chose to do so. I do redirect bass via bass management to existing multiple "large" speakers so the bass couples to the room in an appropriate manner.

If you would take the time trying to understand why "some prefer to throw a lot of speakers around the room" then you would understand why setting all speakers to large can't provide the same quality as an optimized multiple subwoofer configuration.
See
http://www.aes.org/e-lib/download.cfm?ID=13686&name=harman
http://www.aes.org/e-lib/download.cfm?ID=13680&name=harman
There are many other papers (see AES).


Old information. I know what they are doing or more like simulating. More research is needed was the usual disclaimer on the crossover frequency issue. As usual, they refuse to admit that bass may be easily reproduced on speakers that are not called subwoofers.

More research here:

http://www.filmaker.com/papers/RM-2SW_AES119NYC.pdf



Quote:
Originally Posted by markus767 View Post

Quote:
Originally Posted by J_Palmer_Cass View Post

I noticed you skipped over the frequency that you crossover from your mains to your subwoofer. I also notice that you skipped over the frequency area where your can hear a transition from mono bass to stereo bass with your specific setup.

I did not "skip over" anything. You refuse to acknowledge basic acoustic and psychoacoustic principles. Just because we can get directional information from low frequency sounds in a free field or a large room doesn't mean it is preserved when reproduced in an acoustically small room. Read Everest, read Toole, even reading David Griesinger (which is a proponent of stereo bass) will help.


I don't hold to your views. All of the papers noted above say that more research is needed.

More research here:

http://www.filmaker.com/papers/RM-2SW_AES119NYC.pdf



Quote:
Originally Posted by markus767 View Post

Quote:
Originally Posted by J_Palmer_Cass View Post

My claim about Geddes is not related to acoustics. It is related to Geddes use of "Geddes custom bass management" as doing things the hard way.

Doesn't matter if something is easy to do or hard to do, what matters is the result.

What are your results? If I remember correctly you only have a SPL meter for acoustic measurements?


I have the same results as Geddes. It sounds good.

Geddes never produced any measurements on AVS. He just said take my word for it. He also was kind of clueless on bass mangement.

I use a RS Digital SPL meter for my microphone. It works fine with TrueRTA, REW and SpectrumLab although it is subject to C scale filtering. High end is limited to about 9 kHz even with the use of compensation factors. I don't design speakers, so close enough for horseshoes and hand granades
Edited by J_Palmer_Cass - 11/3/12 at 9:54am
post #89 of 163
i'm going to talk like an audiophile .. and dont mistake me as a person that needs to cling onto the expensive speakers to hold an audiophile status ... because talking about bass redirection and subwoofers is easily one such example to prove being an audiophile requires a longer list.


first of all..
audio engineers are doing what they do best when they sell main speakers that dont play bass and they sell you a subwoofer that will fill in the gap.
because of changes as to how the subwoofer fills the room with bass much better ... because of how much lower the subwoofer plays .. because of how much has been put into making the mono bass go further to the point where it is harder to localize the source.

all of this has been done to give them a chance to show off what can be learned, what can be organized as a team effort, and how those two things can get an organized industry into the homes of thousands upon thousands of people.


but that doesnt say the parenting and examples they've given the world are accurate, perfect, or rationally useful.
sad but true, if you need to hear it.
because 'reference' doesnt simply mean the sound from the speaker sounds like you were standing there next to the person talking into the microphone.
....no
reference also means, if the bass came from the left.. then the bass comes from the left speaker, not the subwoofer in the center of the front wall (or the side wall, or behind the couch, or in a front corner, or everywhere where you cant tell where it came from)

you dont need super expensive speakers to make this happen.
you could build your own speakers with MDF wood.
price for a tweeter is $20 - $100?
price for a midrange is $20 - $100?
price for a woofer is $40 - $200?
price for wood is $40 - $60?
price for the a pair of crossovers is $30 - $150?

on the lowest side you spend $150 per speaker.
on the highest side you spend $610 per speaker.

do you see those speakers and think they are trash that cant output clarity as good as the speakers in best buy?
anyways..

if your center channel is too small to output bass, then chances are the bass is going to the front left and right speakers.
for reference localization, it is a big deal.
for some 'so what!' from a modest audiophile, it isnt a deal breaker.

but
if your left front speaker is supposed to be playing bass, or the right front, or the left rear, or the right rear .. and then the bass goes to the subwoofer..?!!!
no, that isnt reference localization.
some people pull their hair out wondering why people are going to surround sound for the localization effects .. but they stop short at midrange and treble only.
yes...
i know it has something to do with how good the audio engineers have made a subwoofer work with the system, because it is candy that tastes good and it is sometimes hard to get a child to put the candy down and eat a real meal.


sad but true, and you need to hear it...
LFE channel is for room pressure tricks and room pressure tricks only.
that is the reference standard.
and yes, if you've got big 12 inch woofers in all of our front and rear speakers .. you could mix the LFE channel with those speakers and it wouldnt be a deal breaker (it would actually be a deal bargain as long as the woofers arent distorting the upper midbass frequencies)

but
this here is the problem..
they know people arent going to go out there and use multiple subwoofers that it takes to get the room to pressurize.
so instead of forcing the reference down their throat (and also because it is more expensive) they simply chose to make the LFE channel work with bass missing from the main layout of speakers.
but that should only turn on when the speakers are set to small ... and the obvious choice for the center set to small is to place it to the front two speakers because they can combine the front soundstage and keep 'center' bass in the 'center' of the soundstage.
nothing in this galaxy should ever change that.

and i'm not sorry.. i've got some 2-way speakers for my rear surrounds with a 6.5inch woofer in a bass reflex cabinet and i can run them as large speakers because the box tune is at 40hz .. but the box loses pressure below that and the cones move more freely, allowing the speakers to gut out some lower bass that gives company to the front bass from the two 12inch woofers.
my two front speakers can play in the 20hz area .. and if i turn on the rear speakers, the 20hz area just gets louder and fills up the rear of the room more.

that is why i look at other people not doing the same as one of two:
1. they havent thought about it
2. they thought about it and anything other than getting on the path to solving the problem is an excuse .. its arguing .. its hatred .. its negligence .. its misconduct .. its defamation aimed towards themselves (and perhaps others too).


does the candy of running all the bass from a subwoofer work?
yes it works,... it works like a sports car with a v6 doing decent 0-30mph line jumps (and a lot of cars nowadays can do this when compared to the older cars from the 80's or 70's or 60's)
and the same thing happened, the engineers got in there and made the 4 cylinder cars do the same quick 0-30mph line jumps.
...simply because the race car isnt fast enough to win every race, that doesnt mean it isnt better than a regular every day driver.. because if they went out in town to race the cars people drive everyday without any modifications , then that race car is always going to win.

and the point?
the LFE channel is for room pressure tricks.
that is why they call it the Low Frequency EFFECT channel.
and no..
you could be listening to the low frequency effect channel and think it is nothing but regular bass.
but to the guy that has four 18inch subwoofers mounted into the wall (false walls) adding up to a room that is about 10ft x 12ft .. those low frequency effects are going to show themselves as different because FINALLY there is pressure in the room.

dont be sorry or sad if your subwoofer can pressurize the room? ... if the door can close and you dont get any hint of a pressure change from the recording microphone that alters the voice character from the person speaking into the microphone .. then your room doesnt get pressurized enough.
no..
those speakers dont need to be accurate and sound exactly like the person talking.
but the reference part was the pressure in the room.
and no..
those subwoofers might not make the gust of wind feel exactly the same as it did if you were really there.
but the reference part is does it exist or doesnt it? .. and if it came from the left, is it coming from the left in the listening room?


i think the most annoying thing is hearing the vocals from the center channel speaker, and then clearly able to tell the bass that should be coming from the center is suddenly 3-4-5-6ft from ____ direction.
if your front soundstage is blended enough that you could go without a center channel speaker, then it wont be as obnoxious.. other than one simple fact ... the bass is expected to be mono, but it shows up in stereo.

surround sound is nothing more than filling up the room with sound in equal portion.
it doesnt need to be completely behind you .. sometimes it stops at the side of you.
but that entire soundstage ... well they call it a soundstage because the whole thing is blended together and you dont know if there is a speaker inbetween the center channel and the front left or right .. because it is all blended and solid.

the rear speakers are only ment to do the same exact thing for behind you instead of in front of you.
do the equalizer with a calibrated microphone and it can help the soundstage blend together a tremendous amount.. but you cant expect that to happen with a simple 3-band parametric equalizer.
at least a 10-band graphic would do a lot more.
and yes, a 32-band graphic would be an upgrade again.

i've done it with a 3-band parametric
and i've done it with a 10-band graphic
i've done it with a 32-band graphic and need to do it again with the 32-band .. but i can wait in happiness with the 10-band because i know it is a large amount better than the 3-band parametric.

i could go as far as saying the difference between a 3-band parametric and the 10-band graphic is like i went out and spent $2,000 on a high-end amplifier.

you can get a whole bunch from the main speakers able to play low like a subwoofer.. because the bass isnt mono-tone.. and if you think of bass like a lightbulb that lights up the whole room, the least you could do is give yourself the pleasure of realizing the single light bulb can be placed where the front left or right speaker is, as well as the rear left or right.
it is like four lightbulbs in each position, and there is somebody there with a switch flipping one lightbulb on at a time .. each lightbulb will light up the whole room, but you can certainly tell which bulb is on .. and that is more 'surround sound' than one lightbulb in one location that stays there for the whole movie.


the answer is obvious, because for one we are talking about 'surround sound'
and for two, i said people allow the 'surround sound' to fall short at the midrange and treble area.
but that isnt the saddest part..
it is when people with one of those setups gets all upset and aggressive with other people because the only thing they care about is the amount of details coming from the speaker or the subwoofer.

if you hadnt already thought about it .. dont trip too much, because it is one of them things were sometimes it was up close and personal.. and they say 'if it was a snake it would of bit you'
but it happens to the best of people, not a single one of us is exempt.
post #90 of 163
It is obvious that you don't know as much as you think that you know. Your only hope is to experience better setups than yours in terms of audio. There is no reference in audio: it is preference.
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