Thanks. I do subscribe to a number of the Forums and get daily notifications of the threads, but don’t find much that I’m qualified to comment on. You guys are way over my head.
Regards,
Wayne A. Pflughaupt
The problem is that an ideal house curve varies from one room to the next. The rule of thumb is, the smaller the room, the steeper the slope needs to be.
Thanks. I do subscribe to a number of the Forums and get daily notifications of the threads, but don’t find much that I’m qualified to comment on.
You guys are way over my head.
Regards,
Wayne A. Pflughaupt
I only speak plain English, but it you’re talking about EQing the main channel speakers, that was only vaguely clear in your original post. Basically I have no problem with it. Based on the frequency response graphs I see in the magazine reviews, most speakers could benefit with some EQ. The problem is that most people don’t know how to do it right, and / or use cheap equalizers to do it, and then when they screw it up they go on the internet ranting that EQ doesn’t work, causes as many problems as it solves, etc.So among all these replies I am still not seeing any comment on my suggestion to smooth the speaker response above the transition and extrapolate it back below the transition but avoid changing the overall spectral balance i.e. don't tilt the target curve off the slope that the speaker finds on its own when placed into the listening environment.
If you’re talking about something that came with a AVR, that is not a measurement mic. For starters, you have no custom calibration file for it, so you don’t know where its response ends and the room’s begins. Those mics only work for AVRs because the calibration is built into the receiver itself.Regarding the phantom power, does Onkyo microphone really require it? Seems to work in my sound card...
If I understand where you’re coming from here, the equalizer isn’t going to give a massive boost to the signal. It will go out at the same level it came in, +/- any overall changes in gain brought by the filters boosted or cut.I am working on the concept of the attenuator. As a rough guess I figure anywhere between +4dB and -10dB line level graphic EQ out needs attenuation back to about -60dB or -70dB dynamic mic level so I figure about 6-7 decades or 2^6=64:1 2^7=128:1 about 100:1 resistive divider or maybe 10K:0.1K should do it?
[POST]204230[/POST]
If you are able to read and understand that paper, you don't need the rest of us . That paper is way, way into the weeds for the topic at hand. It is written for someone designing an Auto-EQ, not as a method to teach people what to do. Specifically, they are trying to solve the problem of the room having different response with respect to seating/mic location. If you listen alone and in the same sweet spot, then you don't need to worry about that. If you do want to create a wider listening area, the solution to that is to measure multiple locations and average them. While there are a lot of papers attempting to show better methods, none are fool proof and simple "spatial" averaging works as well.I looked over that post and frankly it confuses me.
I just started watching the video but I read this paper:
Robust Loudspeaker Equalization Based on Position-Independent Excess Phase Modeling
http://202.114.89.42/resource/pdf/1545.pdf
They show a couple of zeros that they are interested in EQing out of the response in fig 1 (they settle on 135Hz zero).
Then they explain that they are adding this correction in the phase rather than the amplitude.
I do . And again, my advice is to not go there. This is not the type of paper you want to read. It is like trying to figure out how to drive a car by reading a manual on how the valves are designed in your engine.They speak of keeping the pre-ringing down to an acceptable level. Fig. 4 Impulse Response Maximum Level Envelopes is supposed to illustrate what, the magnitude of the pre-ringing? What is a Maximum Level Envelope (google reveals nothing). The only thing I could find that looks promising is this:
https://upload.wikimedia.org/wikipedia/commons/b/b3/EnvelopeAnim.gif
https://en.wikipedia.org/wiki/Envelope_%28mathematics%29
so I am assuming that what they are presenting in that graphic is a family of curves derived off impulse responses but no function is given to define the family of impulse responses. I fail to understand why impulse responses would appear to converge to a non-zero level at infinite time though... they should all converge to zero.
Fig. 5 shows that the step response is faster and squarer but what is an 'average energy step response'? Fig. 6 shows something called Schroeder Decay with apparently significant improvement with a full spectrum signal but nearly no improvement below 300Hz when they were equalizing a zero at 135Hz and this result is counterintuitive.
Something is flying way over my head. Does anyone at WBF understand this paper?
I only speak plain English, but it you’re talking about EQing the main channel speakers, that was only vaguely clear in your original post. Basically I have no problem with it. Based on the frequency response graphs I see in the magazine reviews, most speakers could benefit with some EQ. The problem is that most people don’t know how to do it right, and / or use cheap equalizers to do it, and then when they screw it up they go on the internet ranting that EQ doesn’t work, causes as many problems as it solves, etc.
If you’re talking about something that came with a AVR, that is not a measurement mic. For starters, you have no custom calibration file for it, so you don’t know where its response ends and the room’s begins. Those mics only work for AVRs because the calibration is built into the receiver itself.
First the cheap equalizer, now the cheap mic. I hope this doesn’t sound too rude, but if you’re serious about all this, you need to “up your game” and spring for the right (read “good”) equipment.
If I understand where you’re coming from here, the equalizer isn’t going to give a massive boost to the signal. It will go out at the same level it came in, +/- any overall changes in gain brought by the filters boosted or cut.
Regards,
Wayne A. Pflughaupt
If you are able to read and understand that paper, you don't need the rest of us .
Those are phenomenal articles Wayne and must read for anyone interested in this topic. They are just as valuable today as they were then for our audience here which does not use AVRs or Audyssey.
We agree on the recommendation to simply boost the sub output as a cheap/easy/free approximation to a sloping down curve for people who do use Audyssey.
So among all these replies I am still not seeing any comment on my suggestion to smooth the speaker response above the transition and extrapolate it back below the transition but avoid changing the overall spectral balance i.e. don't tilt the target curve off the slope that the speaker finds on its own when placed into the listening environment.
I was thinking that was potentially an evolutionary step toward determining a house curve by introducing the concept that a correctly chosen speaker in a well treated room already does a fairly good job under its own steam because that is the way it was designed to work in the first place.
That thread here:
http://www.hometheatershack.com/forums/rew-forum/96-house-curve-what-why-you-need-how-do.html
completely validates my suggestion IMO.
The rationalization I use to explain what so many EQ-hating people report is that humans are very forgiving of aberrations that do not affect psychoacoustic perception.
While the power response is directly audible to a microphone with slow sine sweeps, power response is sort of non-sequitor to humans. What we care about more is being able to locate a sound source in space (imaging) with good intelligibility and that is strongly dependent on our ability to distinguish between direct and ambient sound using precedence effect.
On-axis speaker response is generally tuned flat and that tuning is psychoacoustically preserved by precedence effect in a small room despite power response being thrown off with ambient reflections, modes, cabin gain etc. so the motivation, the 'problem I am trying to solve' in Amir's parlance, is not letting the room EQ corrupt that on-axis response with a target curve that alters the spectral balance of the sound power, disrupts the perception of the precedence effect, and destroys the imaging.
I was sort of wondering why no one is marketing an EQ that detects the native 'house curve' of the speaker with no EQ on it and just smooths that native response rather than imposing a target upon it.
Regarding the phantom power, does Onkyo microphone really require it? Seems to work in my sound card...
I am working on the concept of the attenuator. As a rough guess I figure anywhere between +4dB and -10dB line level graphic EQ out needs attenuation back to about -60dB or -70dB dynamic mic level so I figure about 6-7 decades or 2^6=64:1 2^7=128:1 about 100:1 resistive divider or maybe 10K:0.1K should do it? Not that familiar with audio.
I’m going to hazard a guess that you have not equalized your sub? If so, that’s the problem, not the “approach.” If the vocals sound “nasally,” I’m going to hazard a guess that you really mean they sound “thin” and lacking warmth? If so, that’s an indication that your speakers may be too small for the room.I agree that those articles are a landmark.
I have tried that sub boost and not liked the boomy/muddy result. The vocals still sound nasally also. I basically discounted that approach.
The mic with calibration file will cost less than $100. The Yamaha EQ I mentioned can be ebay’d for usually less than $150.For REW I would have to buy a microphone.
I already sank over $6K into this system. Funding is not immediately available for such expenditure.
Okay I think I finally get it. You’re ultimately running the signal into the receiver's calibration mic input? I don’t think you mentioned that specifically, so I figured you were using one of the regular inputs. Hence my comments that no post-EQ gain adjustment is necessary.Analog EQ Plan is:
Audyssey mic -> preamp (mixing board) -> analog EQ -> 100:1 attenuator -> receiver
Set all bands to unity gain and adjust the in/out gains of the preamp/EQ until I can duplicate the receiver's 75dB subwoofer SPL in the auto cal routine. Now gains are all matched.
Adjust the EQ to the inverse of the Harman curve with unity gain at 600Hz.
Run auto cal. Cal result resembles Harman curve rather than Audyssey 'flat' curve.
Plug-in-power (PiP), is the low-current 3 V to 5 V supply provided at the microphone jack of some consumer equipment, such as portable recorders and computer sound cards. It is also defined in IEC 61938.[11] It is unlike phantom power since it is an unbalanced interface with a low voltage (around +5 volts) connected to the signal conductor with return through the sleeve; the DC power is in common with the audio signal from the microphone. A Capacitor is used to block the DC from subsequent audio frequency circuits. It is often used for powering electret microphones, which will not function without power. It is suitable only for powering microphones specifically designed for use with this type of power supply. Damage may result if these microphones are connected to true (48 V) phantom power through a 3.5 mm to XLR adapter that connects the XLR shield to the 3.5 mm sleeve.[12] Plug-in-power is covered by Japanese standard CP-1203A:2007[13] A similar line-powering scheme is found in computer sound cards. Both plug-in-power and soundcard power are defined in the second edition of IEC 61938.[14]
These alternative powering schemes are sometimes improperly referred to as "phantom power" and should not be confused with true 48-volt phantom powering described above.
I’m going to hazard a guess that you have not equalized your sub? If so, that’s the problem, not the “approach.” If the vocals sound “nasally,” I’m going to hazard a guess that you really mean they sound “thin” and lacking warmth? If so, that’s an indication that your speakers may be too small for the room.
What speakers are you using, and what is the size of your room (cu. ft.)?
The mic with calibration file will cost less than $100. The Yamaha EQ I mentioned can be ebay’d for usually less than $150.
Okay I think I finally get it. You’re ultimately running the signal into the receiver's calibration mic input? I don’t think you mentioned that specifically, so I figured you were using one of the regular inputs. Hence my comments that no post-EQ gain adjustment is necessary.
An easy way to decrease the output after the EQ is to simply use a second pro-audio mixer. Plug the EQ output into one of the channels, then reduce the main output to where you need it.
And the whole idea is fool Audyssey into auto-calibrating a Harman curve? Problem is, it’s never a good idea to use a “pat” house curve. As fully discussed and explored in my house curve article, every room is different. The slope you need will depend on the size of the room and your distance from the speakers.
Honestly, you could easily accomplish the general Harman slope with the receiver's tone controls, after Audyssey has auto-calibrated flat response. A bit up with the bass control, a bit down with the treble control would do it.
Regards,
Wayne A. Pflughaupt
I have never seen an AVR mic that needs phantom power. I would not send it juice.Hey veryone thanks for your helpful insights
I am having some difficulty with the Audyssey mic.
It seems that the Zoom R24 mixing board will not generate any output with the Audyssey mic, though my computer sound card will. I am going to try to get analog output working on the sound card so I can use it as a preamp.
https://en.wikipedia.org/wiki/Phantom_power
https://suite.io/richard-mudhar/1prr2nh
https://suite.io/richard-mudhar/24hr2nh
My Fluke tells me that the Onkyo is generating 5V at 1mA. I guess that means I need to add a 5V supply and a 5K resistor (4.7K?) to power the Audyssey mic, or use the sound card as my preamp.
Fortunately I was bright enough not to turn on the phantom power on the mixing board. 48V might have damaged the mic.
Will let you know what happens.
Current plan is to use the Zoom as a pre-amp with a 5V/1mA plug-in power adapter (probably DIY) and put 100:1 attenuator on the output of the Behringer.
How does a human only hear the on-axis response?That was what I objected to in Harman's study, was the choosing of a curve that sort of fit one speaker in one room and claiming the job was finished because people liked the sound. What else was to be expected? What they needed to do was teach the EQ what the general countour of the un-EQd response is, with smoothing, and use that as the target. Done. Simple, but apparently far simpler for a human that can actually hear the on-axis response through the music and tune it using the DSP in the brain to understand and analyze it.
Hey veryone thanks for your helpful insights
I am having some difficulty with the Audyssey mic.
It seems that the Zoom R24 mixing board will not generate any output with the Audyssey mic, though my computer sound card will. I am going to try to get analog output working on the sound card so I can use it as a preamp.
https://en.wikipedia.org/wiki/Phantom_power
https://suite.io/richard-mudhar/1prr2nh
https://suite.io/richard-mudhar/24hr2nh
My Fluke tells me that the Onkyo is generating 5V at 1mA. I guess that means I need to add a 5V supply and a 5K resistor (4.7K?) to power the Audyssey mic, or use the sound card as my preamp.
Fortunately I was bright enough not to turn on the phantom power on the mixing board. 48V might have damaged the mic.
Will let you know what happens.
Current plan is to use the Zoom as a pre-amp with a 5V/1mA plug-in power adapter (probably DIY) and put 100:1 attenuator on the output of the Behringer.