Rational Acoustics



jinkemao
May 2nd, 2012, 05:17 AM
Hello, everyone,
my English is not good, I have a question?

Equal loudness curve, has been more contradictory, music playback, the environment is very perfect, adjust the EQ loudness, 85dB, smaart test a straight line (fiat) sounds good point 100dB something noisy, 120dB as straight, the 2500HZ is very noisy, whether according -6dB.,to the book494

thinaks

Kip Conner
May 2nd, 2012, 04:32 PM
Are these your measurements in the attached image?

Are you saying that your systems sounds good at the 85dB mark and as you increase the SPL to 100dB it gets noisy in the 2500kHz range?

Or is this a general question to how manufacturers set their EQ to produce loudness contouring?

Dr. J
May 2nd, 2012, 09:12 PM
Yeah -- I am not sure exactly either but IF this is what you are getting at great. If not -- sorry for my post. :cool:

I know the Coherence trace only needs to be so high for the data to be considered valid (I guess) and this doesn't mean the system has to be at concert level. This is what I am told. However, I am forced to think otherwise by my results.

In fact -- I have never really cranked the system up for measuring due to neighbors. With that said -- my results have been very similar to yours (in your graphs) at least from a harshness standpoint in the upper frequencies through listening at higer volume levels during shows. I have only measured at shows a few times and it simply is too hectic because I am in the Club / Bar scene where the management don't get this. Great sound is a given (as it should be) and I am lucky if we even get a quality sound check in.

I am convinced that through all the trial and error I have gone through that the system needs to be tuned at the volume you are going to be playing at. Some will disagree but until I get to be as good as they are at this stuff -- this is where I am at.

An easy way to check yourself is by recording your MAIN out on your console BEFORE it gets to your system EQ. If your board mix is DULL -- then your System EQ is set too bright. If your board mix is too bright -- then your system EQ is too Dull. This is REGARDLESS if your trace is flat or not.

For me -- tuning at low volumes translated into an overshoot once the system was roaring at show levels and the harshness and brightness manifested itself something fierce. I knew I couldn't accept the FLAT trace at low levels. This is of course outdoors. Inside -- alot of those levels once again changed due to the heavy buildup of certain frequencies.

I began recording the main out and listening with a known flat response set of headphones. If my headphone sound was DULL and I took them off to hear the system screaming in the high frequencies -- I would make a cut on the system EQ. I would go back and forth until I knew I thoroughly messed up my perfect FLAT trace.

At some point where the system was more tamed to match the headphones -- I would stop. The next opportunity -- I would do another outdoor tuning and fire up the system AS IS from the gig only to discover YES my flat trace is no longer there and my high frequencies are much lower (-6 dB) than the mid area. Interestingly -- the phase response still looked like it did before. I see many on here say the phase response is what matters not the frequency response. Bob McCarthy says the flatter the magnitude response the flatter the phase response. Hmmm -- I may not be doing it correctly then. He also states that the magnitude response need not be flat in order to be smooth. A tilted spectrum (that is essentially flat but tilted) is just as good as a perfectly flat system.

In any case -- I would go ahead and smooth out the new trace that isn't FLAT anymore to its new shape and go out to the gig and repeat. I would then EQ instruments on the board to sound correct in the headphones which then again made the system sound bright -- this would make me get back into the system EQ and make more cuts UNTIL the sound off the console was more in alignment with the sound coming out of the speakers.

The trace I have now is anything but FLAT. It is more like a slope of a roller coaster with a buildup heavy in the low end with a series of dips and hills down to the high end of the spectrum. At my next opportunity -- I will post a snapshot.

I own my system and I use the same mics - same everything - everytime, so I think I can get away with this. It brings up the discussion of should the system be neutral or should the board be neutral. I personally think the board mix should sound accurate without speakers even hooked up to it but that is just my opinion. I know if done accurately -- that is what Smaart is all about but Smaart has operator errors. ie. ME

The flat response headphones (Ultrasone HFI 680's) have pointed out to me that my outdoor low level tuning strategy needs refined. It is my check point.

Perhaps soon I will be able to get the system outdoors and run it at concert levels to see the difference -- if there is any. The traces you showed -- imply that it does. The recorded main out with a different know source helped to give me another angle and I have to say has made a fantastic difference in my system.

Also music played thru the system with NO EQ should sound good from the start.

I now have a curve set for MY system that sounds better than it ever has and it is far from Flat. I am curious how it will sound at an outdoor event but I won't get to test that Curve out for another month and a half. Maybe a more flat response would be better suited for the outdoor stuff??? I will find out.

Don't know if this helps or not but if you own your own system and everything pretty much stays the same gig after gig then I bet you would benefit from this a great deal.

BTW -- This is a Dave Rat inspired method in which he learned from someone else and shares with his friends. For me -- it does indeed work great & I will never make my system flat again because the way I am interpreting the data -- just doesn't work.

FLAT is just a good starting point to get familar with the system. IMO

jinkemao
May 2nd, 2012, 11:04 PM
I think this is recording the CD 85-90dB, However, we replay the 100-120dB Speaker on-asix curve is flat, we have a EQ method, the human ear sound pressure regulator.

85dB 90dB 100dB 120dB

According to this sense of the human ear curve, the need to 2500Hz-6dB to listening to a sense of balance.

This music CD playback, how balanced, according to the sound pressure change, the human auditory system is more balanced。





Thank you

jinkemao
May 2nd, 2012, 11:09 PM
in the Club / Bar need.... Thank you

luigichelli
May 3rd, 2012, 09:10 AM
Jinemao, we assume that a pa is a linear system…
think to a linear equation
eg: y=2x
it's the same of doing 2y=2(2x)

so that's what smaart assumes…
you can tune your system at low db spl since it's linear, and will react the same at higher spl.

Distortion is a non linear function…

Our perception is not linear, but this is a different thing, we are tuning a PA not our ears.

Pls correct if i'm wrong :D
Regards,
Luigi.

PrestonSoper
May 16th, 2012, 10:42 AM
Here are a couple of links that may be appropriate for this thread:

Howard Page article on excessive low end in system tuning
http://clairglobal.com/2011_news/2011/LowEnd.pdf

Frequency Response Contour EQ
http://soundforums.net/varsity/2348-frequency-response-contour-eq-full-range-systems.html

Dr. J
May 16th, 2012, 11:42 PM
Here are a couple of links that may be appropriate for this thread:

Howard Page article on excessive low end in system tuning
http://clairglobal.com/2011_news/2011/LowEnd.pdf

Frequency Response Contour EQ
http://soundforums.net/varsity/2348-frequency-response-contour-eq-full-range-systems.html

Thanks Preston! I have actually been following the "Sound Forums" thread until it died out. I have somewhat approached my system tuning in reverse order...... LoL Well -- initially I tuned it outdoors to be flat from 100Hz on up to around 8kHz BUT once I got it inside a place the lower frequencies like 100-300 even up to 500Hz just went thru the roof. I was cutting them out on the channel strip and all kinds of things you shouldn't do until I recorded my main out. I was horrified at the board mix....:D So I started exploring how to make it sound correct simply because I am asked occasionally if a recording can be obtained off the console. So I started mixing with headphones to make it sound correct at the console and then just did what I had to do at the System EQ to bring it back. The next day I would drag the system out back and fire it up to look at the trace NOT fooling with the shape or contour of the curve BUT making it smoother throughout. Then I would take it out to a gig and repeat. I have done this about four times now -- each time refining the initial curve. I have never been happier with it. I can mix with headphones on and take them off and the system will sound very close except the sub lows and extreme highs. I would be happy to give someone a board feed now because it sounds more in balance than before. I really dig using Smaart for all kinds of things but this was one way for me to use a little of everything (smaart, CDs, recordings & headphones) to refine my system.

I also did this with all my monitors too. Seemed to really clean up the overall tone. The changes I made to my system EQ (DR260) of course were on the INPUT side and not the Output side. The output side is dedicated to driver corrections (completely flat) & I will most likely never touch those.

Thanks again for the article links.

Dr. J
May 24th, 2012, 12:23 PM
Jinemao, we assume that a pa is a linear system…
think to a linear equation
eg: y=2x
it's the same of doing 2y=2(2x)

so that's what smaart assumes…
you can tune your system at low db spl since it's linear, and will react the same at higher spl.

Distortion is a non linear function…

Our perception is not linear, but this is a different thing, we are tuning a PA not our ears.

Pls correct if i'm wrong :D
Regards,
Luigi.

Yesterday for the first time ever --- I got to do a tuning session outdoors where I pushed the system pretty hard. I will say that my initial trace DID NOT change at high volume compared to low volume. However, the coherence trace was a high as it would go (LOL) BUT I will say there is something to higher volume levels for the subs. I have EQ'd the subs in the past at low volume only to see it change with high volume. I just did this again yesterday and when the subs were pushed -- the trace just takes on a different shape.

Now about how the ears hear....... I see what you are saying Luigi. Seems to me that if it is our ears changing with higher dB levels then are there ways to compensate for that with Smaart? If our ears are waay more sensitive to 3.5k at 115-120dB than say any other frequency lower than it -- why in the world would we ever want it to be equal with it? The sound guy is just going to cut it anyways.

My system trace looks more and more like the Equal Loudness Contour trace....... at least in the 2.5 - 4k region. Anyways -- thanks for your input! I still have tons to learn.... :D

Ferrit37
May 24th, 2012, 01:44 PM
Hey Dr. J,
The change in EQ or contour on the subs from low level to higher levels suggests that the subs are being pushed into a non-linear region, prehaps more 2cnd harmonic distortion.
Also remember that changing the level of a passband will affect its acoustic crossover point.

cheers

luigichelli
May 24th, 2012, 06:00 PM
Hi Dr. J.
i'll explain why i tend to tune a flat pa:
ideally you want to amp the sound emitted by a violin/singer/etc... without altering its tone.
For this job you have a base setup that is a flat (or tailored for the source) mic and a pa.
The logic says that you want a flat pa too so your sound won't be altered!

If our ears are more sensitive to the 2-3k range (expecially at low dBSPL) it's not our job to compensate....
that mid-hi range is where the intelligibility is, it's dangerous to cut it down.... i'm quite sure that the mix engineer won't cut it so much as you think he should :D

If your trace is altered at a higher spl, you've gone too far for your pa (as ferrit noted)....or maybe things like the stage are starting to resonate?

Dr. J
May 24th, 2012, 06:23 PM
Thanks guys! Figures...... :D Let me ask this...... Where do you spend most of your time tuning systems -- Indoors or Outdoors?

Do you still strive to make them both flat? I understand some dips may need to stay put due to a cancellation or whatever.

Another thing I just noticed on my computer. I have a front jack and a back jack for plugging speakers into or headphones. I always use the front jack because it is easier to access. I plugged into the rear jack & it sounds totally different. One way sounds full & the other way sounds completely lifeless.... no low end whatsoever.

I checked EVERYTHING I could think of in my computer and I cannot find any equalization taking place. How do we know for certain when using computers for pink noise playback that there is NO EQing going on so it doesn't affect the tuning?

I am thinking the Rational NoiseStick may be the way to go...

Arthur Skudra
May 24th, 2012, 07:27 PM
Thanks guys! Figures...... :D Let me ask this...... Where do you spend most of your time tuning systems -- Indoors or Outdoors?

Do you still strive to make them both flat? I understand some dips may need to stay put due to a cancellation or whatever.Indoors you're dealing with the reverberation of the room and reflections. Outdoors you have very little of that, however you need to take into account changes in relative humidity. Obviously the equalization of a system will be different between the two. So it depends.


Another thing I just noticed on my computer. I have a front jack and a back jack for plugging speakers into or headphones. I always use the front jack because it is easier to access. I plugged into the rear jack & it sounds totally different. One way sounds full & the other way sounds completely lifeless.... no low end whatsoever.

I checked EVERYTHING I could think of in my computer and I cannot find any equalization taking place. How do we know for certain when using computers for pink noise playback that there is NO EQing going on so it doesn't affect the tuning?

I am thinking the Rational NoiseStick may be the way to go...More than likely you're dealing with a true line out at the back of the computer, and a headphone amp at the front. The output impedances are likely different between the two outputs, which explains the difference you perceive in the bottom end. Pick one output, and use that for everything, or get an external interface, or use a noise stick.

Rasmus Rosenberg
May 25th, 2012, 07:22 AM
Oki here is my take.
What I see a lot, is that people target a given response in one equalization process. My guess is it comes from the "normal" way of putting a PA up according to the manufactures spec's and then "only" having a GEQ on the L+R buss. In that end response will be, any PA-Room correction, Any "my ears do/don't like that Frequence", Eq based on perception (conture) and properly more. While the process is "valid" and works, its based a lot of personal preferences and therefore is hard to defend, who is right and who is wrong? Who has responsibility for the perception of the mix? Thats has lead to the path: In system optimization EQ don't have an Agenda, either you need it or you don't. Or as taught in Smaart class: you need to define the line between whats artistic and whats engineering... Any way what my point is: is that every time we close our eyes and don't use your tools to do what we want from them, we accept a bad compromise.
Tuning anything flat is "great" on the engineering side of things, as its much easier visual to sum something that has a "straight" response than a "tilted". However no one is used to listen to music on a "flat" speaker system. As mentioned in a previous post even if you have a "flat" studio speaker, once you put it in a room the response, at the listening position will be "tilted". So should the system tech just "give up" as long as the engineering "side" of things is forfilled. IMO no, being a system tech is providing a service helping the Mix engineer to deliver his mix to the audience. And IMO thats where the hole "conture" / over all EQ, come into the picture. And that is IMO done better and faster with a collaboration between the mix and the system engineer.
Anyway sorry for babbling: I'm just a little tired of the hole "auto pilot" mentality when it comes to speaker systems. Use the tools you have and get on with it.
Mvh
Rasmus

jinkemao
May 26th, 2012, 02:10 PM
Dear friend, EQ flat, does not necessarily sound OK, even if the time alignment, the sound will be unbalanced, because the horn directivity, SMAART software, you can see the speakers plants to adjust to a good speaker position, I tried, two-way speaker, the speaker put, put time alignment, etc., the former is not nice, treble and bass separation, however, curve, or straight. . .

Sub-frequency processor adjustment, time alignment, the curve is straight, right or wrong, sounds more treble, fast.

Have seen some of my friends said the general, use SMAART curve 200hz-3dB 400-500hz is also a fall-3dB better listen, but do not balance. . .

Harry Brill Jr.
January 28th, 2013, 11:57 PM
I couldn't read your entire post as it's just too long and I'm too tired. I wanted to address the general theme though. I am unsure what the OP is asking but you seem to be stating that if you measure at a low level and get your system flat (ish) your system can be too aggressive when it's much louder. Of course this is true, but it has nothing to do with your measurement and everything to do with your ears. You need to use your EARS at show level for that final tweak. This has always been the case. Perhaps someday using known gain devices such as the Smaart i-o, and input from the user, Rational will add a variable weighting curve based on expected SPL. I doubt that would happen in Version 7 but it's just speculation on my part. Along with known gain, I asked for this feature about the time the company started. I think it's still a ways off. Many folks still don't turn on the transfer function or understand why they should.

Harry Brill Jr.
January 29th, 2013, 12:02 AM
Your subs are distorting when you push them. The response is changing because of added harmonic content. You should tune that last 5-10% with your ears. You can do the rest with Smaart at the lowest level that the coherence does not increase, but at some point you will have to turn the system up to show level and use your ears. It's not the system that changes, it's your ears. Of course if the speaker is distorting, then the response will get harsh, or in this case your low end is changing emphases.

Harry Brill Jr.
January 29th, 2013, 12:07 AM
I like this post. Where is the like button? I agree about using a linear, FLAT PA. That does not mean I want my mix to be FLAT. I like a very curvy mix. I get the sound from the desk. If every vendor presented me with a FLAT linear PA when I mixed, my mix would always sound the same, right? Every system tech has a different idea of how the PA should be tuned in regards to EQ. Linear in this context means what goes in, is what comes out. What goes in, from my desk, is a somewhat bass heavy, punchy mix. That's what I want to come out. I'd rather not have the subs hay-stacked a bunch. If the PA is flat, then recordings from the desk will also sound good when played back on neutral equipment.

Harry Brill Jr.
January 29th, 2013, 12:10 AM
Sounds like you had a lot of build up, probably due to being indoors. Correcting this in the system EQ is the right thing to do. Good job.

Dr. J
January 29th, 2013, 11:07 AM
It is good to see some activity here besides the Marketing hacks...... Harry -- when you use music to finish up your tuning -- do you make it sound the best you can with the system EQ OR are you shooting for something else? I like your music selections in the Repository...

Harry Brill Jr.
January 29th, 2013, 08:08 PM
I use music and voice. I do use the system EQ but I don't just try to make it sound good. I also try to make it sound like my cans, which sound pretty good, but more importantly, I'm used to them.

Harry Brill Jr.
January 29th, 2013, 08:25 PM
Believe it or not I don't always pull out all my mics! I know it's shocking!!!

Dr. J
January 29th, 2013, 08:26 PM
I use music and voice. I do use the system EQ but I don't just try to make it sound good. I also try to make it sound like my cans, which sound pretty good, but more importantly, I'm used to them.

Thanks Harry - you are a step ahead of me.... I was going to bring that up next. I do the same and it works quite well. Do you find that the cans are at least a little close in flatness compared to your Smaart readings? I have to admit that even my best effort using Smaart and moving the mic in many places - the final outcome doesn't sound like my cans straight off the deck. I use the Ultrasones HFI 680's. Dave Rat's number 2 pick over the Denon's for live sound.

I then use my Main Parametric to adjust with music in the room while listening with the cans....

Just wondering..... I had a guy come up and ask me to quickly help him with his system.... No time, no verification or anything..... Just threw in a disc and made it sound the best I could and said "There..... Try that".

Dr. J
January 29th, 2013, 10:38 PM
Opps... Not Over the Denon's but next pick To the Denon's.... Ha.

One other thing to clarify.... The music comes off the deck with NO EQ..... As is thru the headphones.... Then the system EQ adjusted to match as best I can... Headphones On and then Off.... Listening and maybe Some low and high end adjustments too.... I am sure most know what I meant by this...... Love this method!

Don C
February 5th, 2013, 05:08 PM
I am new to this forum (joined today) and this has been an interesting first discussion to read through. The systems I work with from Front of House are generally pretty well tuned to begin with, so I tend to use the Smaart Transfer Function (v5 and now v7.4) to "pink" the room or stage if we're outdoors and use parametric EQ when there are sections of frequencies with more than 6db of difference. Then I use music, .wav quality jazz and my ears to set graphic EQ at show level to personal preference. Artist engineers have always been pleased with the condition of the system when they take over. Hope this gives some thoughtful insight into this discussion.

gluis
February 6th, 2013, 07:43 PM
I used get people nervous by using mainly jazz (and some standard system tune songs like Bird on a Wire from Jennifer Warnes) as final tuning music on Rock events LOL.

Seriously, you have to use whatever you know well to final tune a system, but always throw in something similar to the event at hand. It might reveal something Jazz will not (if there will be playing something different than Jazz material that day) and you will appease musician's concerns :rolleyes:

GS

Don C
February 7th, 2013, 12:39 PM
Very good point about music to tune by ear with. When we set equipment up for others (mainly country artists) our setup is done well before they arrive so it is mainly to ensure operational quality without taking any value to an extreme. But it is interesting to hear the variety of music engineers will use. On a humorous note though, very few use country

jinkemao
February 12th, 2013, 11:28 AM
Thank you, I learned a such a long time, my sense of hearing is 110dB, 1K 10K, 1 octave-2DB good pop music, 85DB flat is very nice!

jinkemao
February 12th, 2013, 11:29 AM
Thank you, I learned a such a long time, my sense of hearing is 110dB, 1K 10K, 1 octave-2DB good pop music, 85DB flat is very nice! indoor

PrestonSoper
March 17th, 2013, 10:53 AM
Here is a link to an article by Dave Rat that covers some of the topics in this thread:

http://www.prosoundweb.com/article/when_hearing_starts_to_drift/P1/

Harry Brill Jr.
April 15th, 2013, 10:34 PM
I have EQ'd the subs in the past at low volume only to see it change with high volume. I just did this again yesterday and when the subs were pushed -- the trace just takes on a different shape.

That's called distortion buddy

Harry Brill Jr.
April 15th, 2013, 10:42 PM
You want a flat speaker but a flat speaker in a room doesn't sound flat. If you make a flat speaker in a room measure flat it will sound harsh because our ears can distinguish direct from reflected, and our ears understand distance. There is loss of HF in the air, and there is gain in the low end do to the room. Outside is easy. You only have to deal with the ground bounce.

It doesn't matter to Smaart which output you use as long as the reference originates from that output.

Harry Brill Jr.
April 15th, 2013, 10:45 PM
Hey don't let the software get in the way of a good sounding system.

Harry Brill Jr.
April 15th, 2013, 10:46 PM
You are doing your own transfer function between your ears.

jinkemao
January 29th, 2015, 10:55 PM
Thank you, these times, I learned a lot, play equipment for sound reduction impact is very large, high sound pressure while playing music case must rely on their own ears adjust。 instrument mic tuning device can refer to the frequency response curve smaart adjustment.
Welcome to China to visit. . .