Is there clarity display possible with higher resolution as the T60M ?

[user44455555]

Hello

I mean the clarity have 1/3 resolution if the clarity can also get such a high resolution as the T60M ?
with treated room i get much more clarity above 135 hz in compare to old untreated measures. I have upto 12 cm basotect foam and Basstraps.. maybe the clarity at least in the bass range can be more precise to see the result precise when place basstraps and foam diffrent ?. i hear that clarity in bass is most problem . the treated room results look in larger parts more worse than untreated in bass because there are only 1/3 resolution

 

[Keith_W]

Please think a bit about what the Clarity measurement is. It has nothing to do with subjective clarity. I think it is the most useless measurement, and I can't think of any application for it.

How REW calculates clarity C50: the first 50ms of the impulse is expressed as a % of total energy measured.

This is the problem: a 20Hz sound wave has a period of 50ms. This means that C50 only captures one sine wave at 20Hz. This would be "very very very early". At 10kHz, the period is 0.1ms. So C50 captures 500 cycles of 10kHz. 500 cycles should be enough to be considered "late". Go look at your impulse response or ETC and see how many reflections you can spot below 50ms. IOW: 50ms is "early" for low frequencies, and "late" for high frequencies. This is probably why REW has a custom clarity time.

On top of this - we know that with most speakers and most systems, the sound power is tilted downwards (i.e. there is more sound power at low frequencies, and less at high frequencies). So the Clarity measurement is severely underestimating low frequency sound power because only the first 50ms is captured.

And here is yet another point: in most typical listening rooms, the noise floor rises at low frequencies because rooms act as a low-pass filter. This is precisely at the same frequency range where output from the loudspeaker drops. As a result, the signal-to-noise ratio is typically very poor in the bass region. Now think about how this would affect your "clarity" measurement if the sound energy of the bass is barely above the noise floor.

As a result, ALL Clarity measurements should be upward tilting - less "clarity" in the bass, more "clarity" in the treble.

I don't think anybody knows what ideal "clarity" should be. If you add more room treatment, your "clarity" measurement will improve since reflections are suppressed and there will be less "late" sound power. If you measure "clarity" in an anechoic chamber, your measurement would look excellent. But we also know that adding more room treatment will REDUCE speech clarity after a certain point. I have looked for papers to see if there is a clarity target, and I haven't been successful. Maybe John knows of a study.

So: ideal "clarity" would only be interpretable above a certain frequency (we don't know what that is) and should have upper and lower thresholds (I don't think we know what that is either). Either the thresholds should be frequency dependent, or the "Clarity" calculation should be applied on a logarithmic scale (longer window for low frequencies, less for high frequencies). And finally: proper interpretation of the "Clarity" measurement depends on capturing a proper measurement with an adequate SNR at all frequencies of interest.

Because I don't find this measurement helpful, I don't look at it at all.

 

[user44455555]

Please think a bit about what the Clarity measurement is. It has nothing to do with subjective clarity. I think it is the most useless measurement, and I can't think of any application for it.

How REW calculates clarity C50: the first 50ms of the impulse is expressed as a % of total energy measured.

This is the problem: a 20Hz sound wave has a period of 50ms. This means that C50 only captures one sine wave at 20Hz. This would be "very very very early". At 10kHz, the period is 0.1ms. So C50 captures 500 cycles of 10kHz. 500 cycles should be enough to be con

A 50 hz wave has 20 ms. so over 2 cycles can see. but it is enough if can see 80 hz upo 135 hz more precise. maybe there are also in higher frequecies sharp clarity gaps. this can only see with higher resolution

ETC have the problem can not see which frequency do the problems the lower the frequency get. the foam does not damp frequencies below 60 hz, but in the ETC can see that level at 60 ms is also lower. so not possible to translate the ms to frequency value

the clarity display i notice show the sound enhancement that can hear better, but i think it need on bass better resulution as 1/3 octave. here is a compare. the blue is the newest measure. here

 

[Keith_W]

That ETC looks excellent, I don't think you have much to complain about.

If you want a better idea what your bass is doing, use the spectro and waterfall. The spectro needs to be "normalized to peak at each frequency" to give you an idea of bass decay. The waterfall should be extended to 1000ms and zoomed out so that you can see the noise floor. Alternatively you could look at RT60 Decay and place your pointer at individual frequencies to examine the decay slope.

I don't think going higher than 1/3 octave will give you any worthwhile information in the Clarity graph. Like I said, it's almost useless at low frequencies.

 

[user44455555]

That ETC looks excellent, I don't think you have much to complain about.

Im always compare with calibrate headphones and mono music. when i reduce in headphone frequencies lower 150 hz, i hear no enhancement in clarity. but when i reduce in speakers lower than 150 hz i still get a enhancement in clarity. larger speakers sound more mud as small speakers. currently i do tests with my biggest and expensievest speakers. the focal alpha 65 evo .without foam it was even more worse, but i see it can be better. expensive speakers did not help . in the ETC i see peaks at ~12.2 ms and 14.4 ms. and 38 ms which are same as untreated. I have not all treat, here can see how room look https://www.avnirvana.com/threads/what-would-you-treat.16270/#post-121292 . but i change foam positions for this new measures

the rt60 decay also not good in bass. it show a problem with that speakers at 200 hz too.
The JBL 104 in compare is excellent, but it is of course weak in bass. It have the smallest case and it is very rounded.
maybe all large speakers are bad or rt60 decay line you see is influenced on the FR huge ? . rt60 decay is very diffrent. speakers and positions are same with same room foam level

in clarity is not so much diffrence see between this speakers. so i do not trust rt60 and more the clarity

here is the rt60 and also the kali lp 6 1. version add. the lp6 have not the longer decay at 200 hz and is in bass decay simular to alpha 65. both have 6,5 inch speaker. i also add the mdat files of that compare

 

[user44455555]

I get in mind the focal have bass knobs to reduce the bass. So i do new measure normal and with 6 db bass reduction. it get only slightly better in RT60 . mdat i upload too. microphone and speaker are in this focal measure exact same place. in clarity is bass stay very same rt60 more diffrence. maybe it is really that large speakers have much more resonances in Bass. so it seem really usefull to have clarity in higher resolution ?

 

[Keith_W]

One glance at your RT60 chart and it is easy to see that you have WAY OVERTREATED your room, look at that - the RT60 at high frequencies is 150ms or less. At times it's less than 20ms. It would sound close to an anechoic chamber. And if you are not used to those numbers, it should be about 200ms or more, to an upper limit of about 500ms. It depends on your room volume and your application. Maybe the target can go as low as 150ms if it's a small room and you are a recording studio.REW has a RT60 target calculator which will display upper/lower tolerances.

It is easy to think that your bass is inadequately treated from this graph since it sticks out like a sore thumb. But remember what the "R" in RT60 stands for - "reverberant". A "reverberant field" means that the SPL at that frequency is the same no matter where it is measured in the room. You may get a 40-50Hz reverberant field in a concert hall, or a large church, or a basketball stadium - but you certainly won't get one in your listening room. You get room modes and early reflections.

And you also get measurement artefacts that will mislead you into thinking the RT60 is higher than it actually is:

I suggested that you extend your waterfall out to 1000ms and normalize to peak at every frequency. You didn't do that, so I did it for you. Now, take a really good look at this waterfall. You can clearly see the noise floor. See what the noise floor is doing? See how it rises in the bass region?

Now look at your frequency response graphs. Take note that the bass is falling below 40Hz.

Conclusion: your bass RT60 isn't high. It's poor signal to noise ratio.

 

[user44455555]

View attachment 89869

One glance at your RT60 chart and it is easy to see that you have WAY OVERTREATED your room, look at that - the RT60 at high frequencies is 150ms or less. At times it's less than 20ms. It would sound close to an anechoic chamber. And if you are not used to those numbers, it should be about 200ms or more, to an upper limit of about 500ms. It depends on your room volume and your application. Maybe the target can go as low as 150ms if it's a small room and you are a recording studio.REW has a RT60 target calculator which will display upper/lower tolerances.

which program you use for rt60 or which setting you use ?. you get for 60 hz 150 ms only. that it is at 800 hz is so low is a precsion error. Rew show for 60 hz more than 300 ms . i think that is true, because the bass sound boomy (there can not good hear the attacks and release in compare to headphone

It is easy to think that your bass is inadequately treated from this graph since it sticks out like a sore thumb. But remember what the "R" in RT60 stands for - "reverberant". A "reverberant field" means that the SPL at that frequency is the same no matter where it is measured in the room. You may get a 40-50Hz reverberant field in a concert hall, or a large church, or a basketball stadium - but you certainly won't get one in your listening room. You get room modes and early reflections.

And you also get measurement artefacts that will mislead you into thinking the RT60 is higher than it actually is:

View attachment 89867

because you normalize all FR peaks to 0 db the waterfall show gap or low level in FR as a bad signal to noise ratio. for example at 600 hz you see a low SNR because the level at 600 hz is very low. short delay time is imporant for clarity because small room reverb sound always mud. I am relativly happy with the sound but maybe i can enhance it more. the problems i want solve is the peak around 200 hz and the gap at 600 hz but only on 1 speaker. the 1.5 khz gap happen from desktop. it is reduce when i put foam on desktop

I suggested that you extend your waterfall out to 1000ms and normalize to peak at every frequency. You didn't do that, so I did it for you. Now, take a really good look at this waterfall. You can clearly see the noise floor. See what the noise floor is doing? See how it rises in the bass region?

View attachment 89868

Now look at your frequency response graphs. Take note that the bass is falling below 40Hz.

Conclusion: your bass RT60 isn't high. It's poor signal to noise ratio.

when the speaker did not output anything i get that results. the high freq noise increase is tweeter hiss.I have another test, with speaker off then it is not see. EDIT: high freq was maybe a car or so noise. i do several measure all below 30 db in bass and high freq below 15 db. EDIT: the low hiss is also ambient noise i throttle my Fans from PC more does not affect the low freq..My PC Fan rotate at 800 rpm. my mcrophone is calibrate so the db values that are show is correct

edit: you see the measure when i reduce the Bass 6 db. the rt60m get shorter in bass. so the SNR is good enough. also in the JBL 104 with less bass the rt60M get shorter. I can later test when make very loud what happen I guess RT60 get larger then

 

[Keith_W]

Please understand what I am trying to tell you: RT60 is meaningless at low frequencies in small room acoustics. The reasons are:

1. There are no reverberant fields, there are room modes. Even at high frequencies, reverberant fields may or may not exist. There are specular reflections. Toole says it should be called "early reflection T60".

2. The 60dB decay can not be achieved in typical domestic loudspeakers unless you play very very very loud, so it is extrapolated from 20dB decay or 30dB decay after a short time lapse (the EDT or Early Decay Time) by simple multiplication. And this extrapolation may be unreliable if the SNR is poor.

3. The SNR is TYPICALLY very poor in the bass region for all the reasons I mentioned in my previous post.

If you think your SNR is so good, then explain why the baseline in the step response in all four of your measurements is wandering all over the place?

Maybe you're right that your bass is boomy. I have no doubt that with all your high frequencies deadened down like that, your bass is relatively untouched.

 

[user44455555]

Please understand what I am trying to tell you: RT60 is meaningless at low frequencies in small room acoustics. The reasons are:

thanks for your answer but wy you not answer my questions i write on top of previous post first ?

which program you use for rt60 or which setting you use ?. you get for 60 hz 150 ms only. that it is at 800 hz is so low is a precsion error. Rew show for 60 hz more than 300 ms . i

also your rt60 display did not show the boomy problem of the focal at 200 hz.

yes i know the theory. and on a untreated room it is true. because i see before no diffrence between speakers. but now i see clear, the JBL 104 have shortest T60. I can also make the jbl 104 much louder so it reach bass level higher as focal at above 50 hz, the T60M is still shorter on JBL 104. this reproducable. so wy

1. There are no reverberant fields, there are room modes. Even at high frequencies, reverberant fields may or may not exist. There are specular reflections. Toole says it should be called "early reflection T60".

2. The 60dB decay can not be achieved in typical domestic loudspeakers unless you play very very very loud, so it is extrapolated from 20dB decay or 30dB decay after a short time lapse (the EDT or Early Decay Time) by simple multiplication. And this extrapolation may be unreliable if the SNR is poor.

3. The SNR is TYPICALLY very poor in the bass region for all the reasons I mentioned in my previous post.

View attachment 89910

If you think your SNR is so good, then explain why the baseline in the step response in all four of your measurements is wandering all over the place?

what do you mean with wandering all over the place ?. I can repeat the measures it give same results. the wandering you see are below 30 hz .this is maybe infrasound from street and very low to hear. remember the lower the frequency get, humans less can hear it. i can do several measurements and mix them, did not change results In rew can increase the measure time of clarity upto 99 ms. so it can be more precise in low bass. this are the results



I can hear 30 hz sine tone and i can locate the position in my room because of foam i add. So the theory that frequency below 120 hz can not locate seem wrong when people can hear ITD (interaural time delay) and room is treatet . with untreated room low bass sound horrible for me as it surround me and speakers are out of phase. so i reducew bass alot before. I can not use a subwoofer, because there are no subwoofers here that can place under the display and are flat. and when subwoofer is lower and not in middle it sound strange, when low bass come from diffrent place than other bass. give strange ear feeling. I align sub correct sample exasct did not help

Maybe you're right that your bass is boomy. I have no doubt that with all your high frequencies deadened down like that, your bass is relatively untouched.

I mean the bass sound boomy from the big speakers focal and kali in compare to headphone. it sound much less boomy and much more clarity as with untreated room. A room can not be too much treated, a headphone have no room reverb. I like the sound of headphone, because i want nothing in my ears or head and headphone music come out of head i like speakers to hear depth of field and sound come not out of head.

thats a clarity with 99 ms time. so a reason more, that clarity is not limit to 1/3 octave. because at 50 hz this look as the jbl 104 is more than 2 times better in clarity as the focal 65

Edit: the mdat file i add too

 

[user44455555]

Here i have done measures with 4 repitations in REW measures. its strange, the higher freq noise reduce 5 db, but on the lower frew SNR does not help. always around 25 db. we have no wind, only the traffic noise. but you see the low and high volume JBL 104 measures, the RT60 is always much shorter as the focal. the strange crazy thing with the focal 65 is that it have with 4 repetitions on 50 hz a much larger RT60M as without repetitions. with the jbl 104 this happen not. the mdat i have upload too. if there happen vibration problems on stand they should be appear more on the jbl 104 because this is much lighter as the focal. you see in JBL 104 with low and high volume is not so much diffrence.