REW Measurements for Room Correction Systems (YPAO, ARC, Audyssey etc) - Page 4 - AVS Forum
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post #91 of 163 Old 11-03-2012, 10:41 AM
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Hmmm..
I wonder how much distortion his analog EQs add...rolleyes.gif
Also How does one tune the room with a light bulb... eek.gif

Just my $0.02... wink.gif
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post #92 of 163 Old 11-03-2012, 11:30 AM
 
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Quote:
Originally Posted by fookoo_2010 View Post

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.

if there was no such thing as reference in audio.. then, as you insist, there are no listening rooms to deliberate what happened.
and certainly you dont want to be the one saying the FBI cant watch a video with audio and not know what happened because they were too stupid to know left from right or front to back or changes in pressure because a door in the other room closed.
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post #93 of 163 Old 11-03-2012, 11:37 AM
 
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Quote:
Originally Posted by M Code View Post

Hmmm..
I wonder how much distortion his analog EQs add...rolleyes.gif
Also How does one tune the room with a light bulb... eek.gif
Just my $0.02... wink.gif

i havent looked around much on analog equalizers.
i know they were popular in the 1960's and 1970's
and i know some people still used analog equalizers in the 1990's
i know they can be made to work without distortion ... and i know some of them add distortion.
but i use digital equalizers that dont noticeably change the sound .. not when i plug them in, and not when i move the sliders.

if you find one that is good, but you cant adjust the slider much because the distortion starts to happen .. then by all means stack up those equalizers and move the sliders until just before distortion and use another one to boost the frequency some more.
at least in the digital world, you dont need to worry about the preamp levels getting too loud for the next equalizer to accept simply because there was boost from the equalizer before it.
(not unless you are using an equalizer that is 'modeled' on something analog .. or the math they use to perform the function is missing the point)

i'm still waiting on equalizers that do some boost, and then if the boost simply isnt enough by say 4dB .. then the equalizer starts to change the phase of that frequency.
but as sophisticated life would have it, nobody knows if the phase needs to go in one direction or the other.
and no master switch is going to help solve that problem for all situations.

lots of linear phase equalizers.
not a single one of them does phase only without any boost or cut.
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post #94 of 163 Old 11-03-2012, 04:12 PM
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Quote:
Originally Posted by Testpattern View Post

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,

That's my understanding. What I have found interesting in my untreated room, YPAO sets the left and right to large and the center to small, surround left/right to large and the surround back left/right to small . This observation is with a system built from identical speaker enclosures. So, YPAO is making a crossover decision based not on the enclosure, but on how the enclosure response is interacting with the room barriers. So I know when I finally get my acoustic treatments in place, I will have have to manually set cross over points and manually EQ each enclosure for the desired response curve. Probably the only thing I will keep from the auto YPAO calibration will be speaker distance, and even then I will try various sub distances to see what works best since YPAO dials in an incorrect distance for the sub.

My goal is to fix as much as I can with the acoustic treatments, then tweak the natural flat response from my JBL enclosures as close to a Dolby EQ curve in the sweet spot as possible. Based on what others have said about noting the nearfield EQ response of the enclosures, maybe dialing in EQ toward the enclosures natural response is a better starting goal/target, and then seeing where to go from there.

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post #95 of 163 Old 11-03-2012, 06:14 PM
 
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well you know you can walk to the opposite end of the room and hear the tremendously large increase in bass.
that is how some speakers get set to full.

it isnt necessarily the phase of the speaker .. but which order of harmonic is being captured by the microphone and focused on.


are you scratching your head confused, or can you clearly hear the accumulated bass as if your head was against the wall or in a corner?
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post #96 of 163 Old 11-04-2012, 01:33 AM
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Quote:
Originally Posted by J_Palmer_Cass View Post

bass management

The diagram I had posted earlier shows how signals should get routed. When in doubt simply run an appropriate test signal. This lets you determine by ear to which speaker(s) the signal is routed. Or simply measure the preamp outputs. If routing doesn't behave correctly, contact the manufacturer or buy a working AVR.
If you want to discuss this topic further please open a new thread.
Quote:
Originally Posted by J_Palmer_Cass View Post

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

So you seriously do doubt that smoothness of frequency response and low modal ringing is a priority in the modal region.
If you want to discuss this topic further please open a new thread.
Quote:
Originally Posted by J_Palmer_Cass View Post

It sounds good.

That's what my mom says about her kitchen radio too.
If you want to discuss this topic (no, not my mom) further please open a new thread.
Quote:
Originally Posted by J_Palmer_Cass View Post

I use a RS Digital SPL meter for my microphone.

Only good for comparative measurements but wrong tool for assessing low frequency performance.
If you want to discuss this topic further please open a new thread.

Markus

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post #97 of 163 Old 11-04-2012, 01:47 PM
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Quote:
Originally Posted by markus767 View Post

Quote:
Originally Posted by J_Palmer_Cass View Post

bass management

The diagram I had posted earlier shows how signals should get routed. When in doubt simply run an appropriate test signal. This lets you determine by ear to which speaker(s) the signal is routed. Or simply measure the preamp outputs. If routing doesn't behave correctly, contact the manufacturer or buy a working AVR.
If you want to discuss this topic further please open a new thread.


There you go again. That generic bass management diagram only applies when all the speakers are set to small and a subwoofer is used. I have a diagram that show the generic bass management diagram for the large mains and small other speaker settings.

There is not much information available to the public on this topic due to non disclosure agreements as well as it may be proprietary information.

My opinion on your knowledge about bass mangement in general still stands.

I guess all of this is a topic for another thread. Too bad, so sad!



Quote:
Originally Posted by markus767 View Post

Quote:
Originally Posted by J_Palmer_Cass View Post

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

So you seriously do doubt that smoothness of frequency response and low modal ringing is a priority in the modal region.
If you want to discuss this topic further please open a new thread.


I have not commented on that one way or the other. Nothing that I have discussed precludes anything about that topic. No discussion is required.



Quote:
Originally Posted by markus767 View Post

Quote:
Originally Posted by J_Palmer_Cass View Post

It sounds good.

That's what my mom says about her kitchen radio too.
If you want to discuss this topic (no, not my mom) further please open a new thread.



Geddes uses the same standard. Measurements need not be produced for the riff raff!




Quote:
Originally Posted by markus767 View Post

Quote:
Originally Posted by J_Palmer_Cass View Post

I use a RS Digital SPL meter for my microphone.

Only good for comparative measurements but wrong tool for assessing low frequency performance.
If you want to discuss this topic further please open a new thread.


Neither is an Audyssey microphone according to your standards!eek.gif


http://www.avsforum.com/t/1328136/measurement-mic-shootout-emm-6-wm-61a-rs-33-2055-audyssey
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post #98 of 163 Old 11-05-2012, 03:42 AM
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Scotty, beam me up!

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post #99 of 163 Old 12-03-2012, 07:10 AM
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Here are some before/after of Trinnov in the Sherwood R-972. These have EQ applied, but not any spatial correction (yet). These are REW measurements with 1/6th octave smoothing. This is with DefTech BP30 speakers and no subwoofer. Room is approximately 13 x 17 x 8 feet. There are absorbers on the first reflection points on the side walls.


The first one is none vs flat:
http://www.avsforum.com/content/type/61/id/99146/
Blue line is no EQ and green line is flat EQ. I do see some correction, but not "total" correction



This next graph is No EQ vs EQ flat vs EQ audiophile1:
http://www.avsforum.com/content/type/61/id/99148/
The third purple line is the audiophile EQ. Notice that below 200 Hz the line is close to the EQ-flat line (green), but above 200 Hz it follows the no EQ line (blue)



Next graph is no EQ vs EQ flat vs EQ natural:
http://www.avsforum.com/content/type/61/id/99152/
The purple line (EQ natural) has a boost of 3 to 4db below 200 Hz over the EQ flat line (green) and a cut of 1-3 db above 10 KHz.

Some waterfall graphs:
http://www.avsforum.com/content/type/61/id/99380/
no EQ, 12th octave

http://www.avsforum.com/content/type/61/id/99382/
flat EQ, 12th octave
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post #100 of 163 Old 12-03-2012, 07:12 AM
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I'd like to measure just what the correction is doing without the effects of the room. Can I just route the pre-outs back to my input on my USB-DAC/ADC? It would be nice to know exactly what the correction curve looks like.
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post #101 of 163 Old 12-03-2012, 07:33 AM
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Quote:
Originally Posted by amt View Post

I'd like to measure just what the correction is doing without the effects of the room. Can I just route the pre-outs back to my input on my USB-DAC/ADC?

Yes.

Markus

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post #102 of 163 Old 12-03-2012, 09:47 AM
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Quote:
Originally Posted by Nick @ Anthem View Post

DS-21, when you originally mentioned peaks in the crossover region I took that statement at face value, imagining a resonance, not realizing that you meant overlap between subs and mains increasing the output. The solution in this case: Since sub and main crossovers can be set separately, just spread out the settings until your ears like what they hear. The problem is that this can only be done on AVM/D, not MRX.

I don't remember if I mentioned peaks or dips, but every time I've run ARC there have been audible and measurable issues with the sum of mains and subs as set by ARC, as measured by full-range mono sweeps from (if memory serves) 16-200Hz. The reason for the issue is that ARC (like Audyssey, et al.) it doesn't do what's needed (a sweep to cover mains AND subs simultaneously) to see how they interact in a room.

ARC isn't alone in this shortcoming, of course. Because I think ARC is by and large better than competing AVR-level room correction systems (and at this point I'm not inclined to spend five-figures on the Trinnov box that would be the only thing more likely than not to be a real upgrade for me over the MRX 300) this shortcomings are more glaring to me.

Admittedly, I'm horrible at saving measurements to files. I'm generally more interested in hearing what happens than in saving my documentation. That's one reason I started a blog, to force myself to save my bloody measurements, and store them where I can access them when I want to make a point.
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Originally Posted by Nick @ Anthem View Post

I remember your inquiry about how LFE is handled and believe the reply from one of the tech reps was to the effect of AVM/D keeps the LFE but MRX doesn't when sub channel is disabled (there's that AVM/D vs MRX problem again). I'm not going to get into the reasons for it, but it's not going to change.

I remember that, ca. last March. But my most recent (and unanswered) inquiry was very different.Here it is, in condense form, if anyone at Anthem wants to take a stab at answering it.

How should I set up the MRX such that ONLY the LFE channel is sent to the sub-out and all the other channels get no LFE channel. Alternately, what settings do I need to make to ensure that an external box gets the 4 signals - LCR+LFE - in their correct proportion for external bass management. Then I can simply send things with an outboard box, and do bass management appropriate to my room and system.

Perhaps to some that question requires "custom engineering." But it seems pretty straightforward to me...
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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. 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.

How did you get the signals routed? FuzzMeasure only has 2-channel output and the MRX doesn’t have multichannel analog inputs.
Quote:
Originally Posted by J_Palmer_Cass View Post

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 tend to be precise about the definitions of words when I write. LFE channel has a defined meaning (aka the point-one), so that’s what I 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

Really? I missed that memo somewhere. I thought his current recommendation was to set the processor to no sub, and do bass management externally.
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 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.

In most rooms, that approach will fix one problem (low bass headroom) but do nothing to fix what is IMO the bigger problem by far: extreme unevenness of upper-bass reproduction from “full range” mains, due to the effect of room modes.
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.

The reason is that we prefer high-fidelity upper bass reproduction over a fairly decent seating area to low-fidelity upper-bass reproduction everywhere.

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post #103 of 163 Old 12-03-2012, 10:12 PM
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Quote:
Originally Posted by DS-21 View Post

How should I set up the MRX such that ONLY the LFE channel is sent to the sub-out and all the other channels get no LFE channel.

Go to Targets, place a checkmark in all Full Range X-Over boxes and type an F in all Response Cutoffs boxes or click them one step below 30 Hz (either way they'll say Flat). This is ARC's way of saying "Large" for all channels. When all channels are Large, the sub only plays LFE as long as the sub channel is enabled.

Click OK, Calculate, Upload to transfer the settings into the MRX.

The most important noise floor is in your head. Always remember to protect your hearing.
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post #104 of 163 Old 12-04-2012, 05:45 AM
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Quote:
Originally Posted by Nick @ Anthem View Post

Quote:
Originally Posted by DS-21 View Post

How should I set up the MRX such that ONLY the LFE channel is sent to the sub-out and all the other channels get no LFE channel.

Go to Targets, place a checkmark in all Full Range X-Over boxes and type an F in all Response Cutoffs boxes or click them one step below 30 Hz (either way they'll say Flat). This is ARC's way of saying "Large" for all channels. When all channels are Large, the sub only plays LFE as long as the sub channel is enabled.

Click OK, Calculate, Upload to transfer the settings into the MRX.

Thanks, Nick. That's exactly what I needed to know!

Two follow-ups:

First, in that scenario (mains getting everything but LFE channel, sub getting LFE only), the subwoofer crossover setting should be set to 120Hz to catch anything that might be put on the LFE channel, right? (That is to say, with a subwoofer crossover of, say 60Hz, theoretically an octave of LFE information will be filtered.

Second, just to confirm, if I play a 2-channel file expanded to surround via DPL2, with the above settings, the MRX will output nothing from the sub channel.

[sidenote: Mods, if this post and the two it quotes might be profitably moved to the big MRX receiver thread.]

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post #105 of 163 Old 12-05-2012, 01:49 PM
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Since it hasn't been moved I'm replying here.

Yea, a traditional recommendation is to cross the sub over at 80 Hz to avoid directionality issues but I see plenty of LFE at 120 Hz so I'd start with that and work it down if necessary. There's little worry that an uncorrected in-room bump at say 150 Hz would still cause directionality because it gets eq'd out.

Side topic - Although directionality starts at 80 Hz this doesn't include the typical setup where a front speaker playing similar content from a similar direction which would set up masking. In a different sense directionality can also be caused by harmonic distortion or mechanical reasons such as port chuffing in a ported sub, broken seal in a sealed sub, rubbing voice coil or unwanted sounds when driver reaches excursion limit (a good powered sub includes protection which would never allow amp clipping or stressing the driver).

So, tweak according to the system.

DPL2 - that's correct. AnthemLogic on the other hand does send content to the sub when playing stereo sources even though all speakers are Large, in case that's what you're looking for.

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post #106 of 163 Old 12-21-2012, 04:44 PM
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If anyone is curious, I have posted a Trinnov EQ correction measurement with comparison to before/after in-room response here: http://www.avsforum.com/t/1397757/r972-trinnov-user-notes/450#post_22732254
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post #107 of 163 Old 12-22-2012, 01:27 AM
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Quote:
Originally Posted by amt View Post

If anyone is curious, I have posted a Trinnov EQ correction measurement with comparison to before/after in-room response here: http://www.avsforum.com/t/1397757/r972-trinnov-user-notes/450#post_22732254

Not sure what you want to show with those graphs. Some additional information what and how was measured would be helpful too.

Could you post frequency response before/after?

Markus

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post #108 of 163 Old 12-22-2012, 07:14 AM
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Quote:
Originally Posted by J_Palmer_Cass View Post


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. [/quote]


On AVS we see a fair number of people who seem to believe that:

(1) Because their speakers are specified to have response down to 20 or 30 Hz, they don't need a subwoofer.

(2) Because their speakers are specified to have response down to 20 or 30 Hz, they only need a subwoofer for the LFE channel

(3) Because their main speakers are specified to have response down to 30 or 40 Hz, they should set their main speaker crossovers to 30 or 40 Hz.

The punch line is that these main speakers are often based on a single or pair of drivers in the 5-6 inch range.

Probably the most egregious case of (1-3) I've seen yet is the Mirage OMD 15 with a single 5.5 inch driver and speced as:

"Frequency Response: 33Hz-20kHz, +/-3dB"

The actual bass generating power of a 5.5" diaphragm with 8 mm Xmax is:

Freq,Hz Max SPL, DB

10 64
20 76
30 83
40 88
50 92
60 95
70 98
80 100
90 102
100 104
110 106
120 107
130 109
140 110
150 111
160 112
170 114

Look to me like good candidates for crossing over at 140 Hz. ;-)
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post #109 of 163 Old 12-22-2012, 08:21 AM
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Quote:
Originally Posted by markus767 View Post

Some additional information what and how was measured would be helpful too.
Could you post frequency response before/after?

This is measuring a front right speaker (no subs yet) with REW using a Sherwood R972 AVR. The room is 14x17x8 feet

The before and after frequency response is already in the graph (yellow and green).
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post #110 of 163 Old 12-22-2012, 08:29 AM
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Quote:
Originally Posted by Steve Dodds View Post

I use a Behringer ECM8000, M-Audio Mobile Pre USB and Mac Mini using Bootcamp. But again, the main thing isn't so much the accuracy of these particular measurements, but rather the effect of the codecs.

I suspect you'll get a better result using the manual EQ on the Yamaha rather than YPAO.
Side question:
Why are you running boot camp instead of the Mac v5 native version on your MacMini?


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post #111 of 163 Old 12-22-2012, 12:48 PM
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Quote:
Originally Posted by arnyk 
On AVS we see a fair number of people who seem to believe that:
(1) Because their speakers are specified to have response down to 20 or 30 Hz, they don't need a subwoofer.
(2) Because their speakers are specified to have response down to 20 or 30 Hz, they only need a subwoofer for the LFE channel
(3) Because their main speakers are specified to have response down to 30 or 40 Hz, they should set their main speaker crossovers to 30 or 40 Hz.
The punch line is that these main speakers are often based on a single or pair of drivers in the 5-6 inch range.

Probably the most egregious case of (1-3) I've seen yet is the Mirage OMD 15 with a single 5.5 inch driver and speced as:
"Frequency Response: 33Hz-20kHz, +/-3dB"
The actual bass generating power of a 5.5" diaphragm with 8 mm Xmax is:
Freq,Hz Max SPL, DB
10 64
20 76
30 83
40 88
50 92
60 95
70 98
80 100
90 102
100 104
110 106
120 107
130 109
140 110
150 111
160 112
170 114
Look to me like good candidates for crossing over at 140 Hz. ;-)

If your main speakers have 2 x 5.5" drivers (my monitor audio gx200 do, for instance), how many dB can be added to the Max SPL column - I am guessing something between 3 and 6dB? Also don't know what the Xmax of the gx200 5.5" woofers is... Currently my subs Xover is set at 120Hz, which seems a reasonable compromise.

I finally put together the Dayton EMM-6 mic and Art Audio Pre/USB to run finally some better measurements. I currently have a Yamaha A1000 receiver, but planning to move to XT32, probably Onkyo 818.

I'd like to take a series of measurements via REW, then share my results. I'm thinking of 3 sets, each as stereo and stereo+subs:

1. no room eq
2. YPAO
3. XT32 (once I get a new receiver)

My experience with REW is limited. wink.gif What set of measurements should I be taking to accomplish my goal? Is the SPL and phase measurement all is needed?
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post #112 of 163 Old 12-22-2012, 02:00 PM
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First. Let me apologize in advance for a double post (also made in Audyssey thread), but you folks seem very keen on small nuances and my question is one of nuance.


1) I have been using this home made 2' x 4' frame for holding the Audyssey mic for my Denon 1909 in the past. It is super quick and easy to just move the mic from location to location. Wondering if this frame might cause any reflections to affect the readings/settings. It is made out of 1/4" carbon fiber kite spars*. Would it make a notable difference to change to use the $20 mic stand located behind the couch?

2) I recently read that it is a no no to have the mic placed on the couch back. Is this still a no no to have just one (not main #1 LP), that is mounted to this frame via a dowel be 'over' the couch back? If so I could create four legs to move the whole assembly forward from the couch back.

(New Denon 2113 AVR en route.)
* A kite flying/ building buddy made it for me

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post #113 of 163 Old 12-23-2012, 05:09 AM
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Quote:
Originally Posted by amt View Post

This is measuring a front right speaker (no subs yet) with REW using a Sherwood R972 AVR. The room is 14x17x8 feet
The before and after frequency response is already in the graph (yellow and green).

Not sure which graph you're referring to. On the linked page I only see impulse responses, no magnitude response graphs.

Markus

"In science, contrary evidence causes one to question a theory. In religion, contrary evidence causes one to question the evidence." - Floyd Toole
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post #114 of 163 Old 12-23-2012, 05:48 AM
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Not sure why that link is not going to the right post. Anyway, look for post number 471 in that thread.
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post #115 of 163 Old 12-23-2012, 07:36 AM
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Quote:
Originally Posted by amt View Post

Not sure why that link is not going to the right post. Anyway, look for post number 471 in that thread.

Found it, thanks. Looks like Trinnov applies less aggressive equalization at low frequencies compared to XT32.

Markus

"In science, contrary evidence causes one to question a theory. In religion, contrary evidence causes one to question the evidence." - Floyd Toole
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post #116 of 163 Old 12-23-2012, 08:09 AM
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Quote:
Originally Posted by BobL View Post

+1 a manual calibration is still best if you have a knowledgeable calibrator. None of the auto EQs do a better job with tuning a room. The only exception to this is Trinnov's remapping feature not its EQ. Calibrator's can't remap but if the system is set up well it is not needed.

I'm pretty much a complete newb when it comes to these new room EQ software but how does one go about manually calibrating their system? I get the measurement part with REW but do receivers with room correction software on them allow you to manually EQ the program as well?
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post #117 of 163 Old 12-23-2012, 09:18 AM
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Quote:
Originally Posted by markus767 View Post

Found it, thanks. Looks like Trinnov applies less aggressive equalization at low frequencies compared to XT32.
7 IIR filters per channel in the 972. In the Pro units, # filters and cutoff frequency i.e. 200Hz, 250Hz etc. etc. are fully adjustable.
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post #118 of 163 Old 12-23-2012, 10:14 AM
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Quote:
Originally Posted by BarracudaDelGato View Post

Quote:
Originally Posted by arnyk 
On AVS we see a fair number of people who seem to believe that:
(1) Because their speakers are specified to have response down to 20 or 30 Hz, they don't need a subwoofer.
(2) Because their speakers are specified to have response down to 20 or 30 Hz, they only need a subwoofer for the LFE channel
(3) Because their main speakers are specified to have response down to 30 or 40 Hz, they should set their main speaker crossovers to 30 or 40 Hz.
The punch line is that these main speakers are often based on a single or pair of drivers in the 5-6 inch range.

Probably the most egregious case of (1-3) I've seen yet is the Mirage OMD 15 with a single 5.5 inch driver and speced as:
"Frequency Response: 33Hz-20kHz, +/-3dB"
The actual bass generating power of a 5.5" diaphragm with 8 mm Xmax is:
Freq,Hz Max SPL, DB
10 64
20 76
30 83
40 88
50 92
60 95
70 98
80 100
90 102
100 104
110 106
120 107
130 109
140 110
150 111
160 112
170 114
Look to me like good candidates for crossing over at 140 Hz. ;-)

If your main speakers have 2 x 5.5" drivers (my monitor audio gx200 do, for instance), how many dB can be added to the Max SPL column - I am guessing something between 3 and 6dB?

3 dB per added woofer or doubled Xmax.
Quote:
Also don't know what the Xmax of the gx200 5.5" woofers is...

Unless I know the actual Xmax for a certain speaker, I use the largest Xmax I've ever seen for a driver like that from a credible source.
Quote:
Currently my subs Xover is set at 120Hz, which seems a reasonable compromise.

Yes.


I finally put together the Dayton EMM-6 mic and Art Audio Pre/USB to run finally some better measurements. I currently have a Yamaha A1000 receiver, but planning to move to XT32, probably Onkyo 818.

I'd like to take a series of measurements via REW, then share my results. I'm thinking of 3 sets, each as stereo and stereo+subs:

1. no room eq
2. YPAO
3. XT32 (once I get a new receiver)

My experience with REW is limited. wink.gif What set of measurements should I be taking to accomplish my goal? Is the SPL and phase measurement all is needed?[/quote]

Neither SPL nor phase will directly tell you much about when and where your woofer runs out of Xmax.

I'm not a REW guru, but what you are looking for is something that lets you know when you have reached something like 3-10% THD.
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post #119 of 163 Old 01-06-2013, 06:21 AM - Thread Starter
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Quote:
Originally Posted by mtbdudex View Post

Side question:
Why are you running boot camp instead of the Mac v5 native version on your MacMini?
Sent from my 32GB iPhone4 using Tapatalk

The Mac version has trouble running when you use an external soundcard. I now use the MiniDSP mic and it works pretty well with a Mac.


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post #120 of 163 Old 01-13-2013, 01:16 AM - Thread Starter
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And here is Emotiva's EmoQ 2 from a UMC200 :







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