Is the EDT curve possible show in RTA measure too to play foam and see fast what happen ?

[user44455555]

Hello

I notice on my speakers when i reduce 250 hz then i hear more clarity sound and sound much better. only when look on FR 250 hz is a gap. so normaly should not reduce that. today i look in rt60 and i see ETD curve that there is even if SPL at this frequency is much lower that value is around 30% higher as other frequency.

I read in rew manual what ETD is.

A fast early decay (low EDT figure) indicates better clarity than at positions where the EDT is higher.

It seem this is an important value for clarity because strong early reflections can hear more. I have some foam but move them around it change nothing noticable in RTA. i only hear and see in the rt60 values that it have some effect.

Then my idea is to show the EDT value in the RTA to see the result of foam placing fast and need not much measure. is this possible and not much work ? I think this is a important feature for room acoustic damping and save alot of time

here are my FR and ETD values so you can see

Edit: WIth omnidirectional microphone measure the 250 hz peak in EDT is too in and higher. and the FR gap is more too with omnidirectional measure

 

[John Mulcahy]

EDT is derived from the impulse response, an RTA measurement does not have an impulse response.

 

[user44455555]

can there maybe do a quick measure mode or a repeat mode that get every 0.5 sec a measure to show the EDT ?. for foam placing it is also usefull when ony measure from 100 hz to 400 hz. when measure go automatic then can hold the foam in hand and see on which foam position the 250 hz EDT value reduce.

 

[user44455555]

The ETD smooth can choose as highest resolution to one third octave . maybe there is easy possible to add 1/6 smoothing too ?.

I use then a burst tone and the scope and look at the specific mode frequency and move foam so it is shortest. when have at least 1/6 is better to find the frequency to watch for decays

 

[user44455555]

I measure a in ear headphone and when set filter order to 48 db the decay time increase alot. see screenshot. which is c orrect ?

 

[John Mulcahy]

From the help:

RT60 data can be shown in octave or one-third octave bands. The Filter order selection controls how steeply the fractional octave band filters roll off. The default order is 6 and that gives results comparable with most other software. Higher filter order makes the bands more selective, which can help isolate longer decays to a particular band, but increasing filter order also increases the delay of the filter itself. That can be mitigated by using Time reversed filtering or Zero phase filtering as described above.