• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

JBL 104 BT measure results with Group Delay

bennybbbx

Addicted to Fun and Learning
Joined
May 27, 2020
Messages
691
Likes
124
Location
germany
This have the best stereo width and depth of field from all speakers i hear. Seem because the group delay have few diffrences. there is a gap at 10 khz when it is around 15 degreee offaxis hear it get more. the group delay i have measure at 8 cm distance because only below 12 cm it give correct results. because its coax can put near. the FR is measure from a distance of 50 cm in my room. be near on the speaker help alot to reduce room reflection influence. see the RT60 decay between 1 meter and 50 cm. i have output volume on the speaker same and microphone record 6 db less.

jbl 104 BT on axis.jpg


jbl 104 noeq off axis.jpg


jbl 104 group delay.jpg


0.5 m distance.jpg


1 m distance.jpg
 

thewas

Master Contributor
Forum Donor
Joined
Jan 15, 2020
Messages
6,757
Likes
16,220
The group delay that you measure at 8 cm is of course advantageous at a small coaxial driver, while on conventional multi-way loudspeakers if you go away from the reference angle the addition at the crossover frequency won't be perfect, giving a step at the GD. But you don't need necessarily to measure GD to see these phenomena, they can be easily observed from the lobes/discontinuities at the vertical frequency response measurements. And confirms what the Harman research has shown, namely loudspeakers with smooth directivity sound and image best as the reflected sound is more similar to the direct one.
 
OP
B

bennybbbx

Addicted to Fun and Learning
Joined
May 27, 2020
Messages
691
Likes
124
Location
germany
The group delay that you measure at 8 cm is of course advantageous at a small coaxial driver, while on conventional multi-way loudspeakers if you go away from the reference angle the addition at the crossover frequency won't be perfect, giving a step at the GD. But you don't need necessarily to measure GD to see these phenomena, they can be easily observed from the lobes/discontinuities at the vertical frequency response measurements. And confirms what the Harman research has shown, namely loudspeakers with smooth directivity sound and image best as the reflected sound is more similar to the direct one.

ok, i have a group delay measure of kali from 1.5 cm too. same 650 hz problem. in the other tests i edit my posts and attach the mdat files, so you can look
 

Attachments

  • jbl 104 8 cm distance.zip
    730.4 KB · Views: 60

thewas

Master Contributor
Forum Donor
Joined
Jan 15, 2020
Messages
6,757
Likes
16,220
ok, i have a group delay measure of kali from 1.5 cm too
At high height did you place the mic? Also the mdat file writes 8.5 cm and not 1.5?

Also the wiggles you get are artefacts from the reflections you have, if window the measurement there is no problem at 650 Hz.

Could you better post a photo of your measurement setup?
 
Last edited:
OP
B

bennybbbx

Addicted to Fun and Learning
Joined
May 27, 2020
Messages
691
Likes
124
Location
germany
Where did you place the mic?

on the 1.5 cm measure was lower. i guess so 40 cm from desktop. but the new 8 cm measure Kali was 55 cm. because my stative is higher for the smaller JBL. the jbl is at 48 cm high measured. you can see in impulse there can no room reflectiomn echo see.
 
OP
B

bennybbbx

Addicted to Fun and Learning
Joined
May 27, 2020
Messages
691
Likes
124
Location
germany
here is the mdat of the 1.5 cm measure from kali and jbl 104 on high stative in middle of my room jbl is so much better. if my room is worse then both need be very simular
 

Attachments

  • kali jbl 1.5 cm high stative.mdat.zip
    2.7 MB · Views: 64

markus

Addicted to Fun and Learning
Joined
Sep 8, 2019
Messages
646
Likes
653
The group delay that you measure at 8 cm is of course advantageous at a small coaxial driver, while on conventional multi-way loudspeakers if you go away from the reference angle the addition at the crossover frequency won't be perfect, giving a step at the GD. But you don't need necessarily to measure GD to see these phenomena, they can be easily observed from the lobes/discontinuities at the vertical frequency response measurements. And confirms what the Harman research has shown, namely loudspeakers with smooth directivity sound and image best as the reflected sound is more similar to the direct one.
You can't measure a speaker at 8cm mic distance and expect any useful data. You need to measure in the driver's far field which begins at a distance of 3-10 times the largest dimension of the sound source.
Furthermore there's diffraction effects from the enclosure contaminating measurements.

Measuring a woofer at a distance shorter than 10% of the driver's radius will yield reliable data up to a certain frequency. See https://audioxpress.com/article/measuring-loudspeaker-low-frequency-response
 
Last edited:
OP
B

bennybbbx

Addicted to Fun and Learning
Joined
May 27, 2020
Messages
691
Likes
124
Location
germany
You can't measure a speaker at 8cm mic distance and expect any useful data. You need to measure in the driver's far field which begins at a distance of 3-10 times the largest dimension of the sound source.
Furthermore there's diffraction effects from the enclosure contaminating measurements.

Measuring a woofer at a distance shorter than 10% of the driver's radius will yield reliable data up to a certain frequency. See https://audioxpress.com/article/measuring-loudspeaker-low-frequency-response

see also my 1.5 cm measure. ok, but it count how much influence in % it is. if it is important or not. how much is it ?. in the example wav you link the floor bounce is much more than i have. I can measure a headphone at 1.5 cm and it have a 5 cm membrane. for this theory i must put the microphone and my ears at least 15 cm away, for this headphone measure i have put the headphone on desktop. somewhere in the step response thead i have a picture of this. the GP of the headphone look much better as kali. and when kali and the other speakers are so good as the headphone then can think to do a better measure method. but when see clear diffrences in the results, the measure mothod look ok. the headphone have at 100 hz a group delay of 2 ms the jbl 5 ms. this is 2 * more. then should be clear if the effects you explain have influence of 10% this is not important if it is 4.5 ms or 5 ms in compare to 2 ms, with the headphone measure the distance to the desktop is around 5 cm and in speaker measure it is 5 cm. should i do a better headphone measure now to show that at a distance of 55 cm 1.5 cm measure distance influence of room is minimal ? you also can see the eris 3.5 group delay at 1.5 cm. this is better in high frequency as the JBL but in low frequency is the JBL better. this i hear, because the JBL have in low freq more clarity in bass. maybe somebody show a group delay of a fullrange speaker. i guess this is much more better as the results i have.

superlux 681 evo headphone.jpg
 
Last edited:

markus

Addicted to Fun and Learning
Joined
Sep 8, 2019
Messages
646
Likes
653
@bennybbbx You again demonstrate that you're lacking very fundamental basic knowledge about a topic you like to talk about in an unduly authoritative way. As already explained in other threads you're alienating people with that kind of behavior. Please take a step back and learn about the fundamentals. Here I recommend that you read about the basics of measuring loudspeakers. There's even a decent German translation of D'Appolito's book:

D'Appolito "Lautsprecher-Messtechnik"

Bye for now.
 
OP
B

bennybbbx

Addicted to Fun and Learning
Joined
May 27, 2020
Messages
691
Likes
124
Location
germany
@bennybbbx You again demonstrate that you're lacking very fundamental basic knowledge about a topic you like to talk about in an unduly authoritative way. As already explained in other threads you're alienating people with that kind of behavior. Please take a step back and learn about the fundamentals. Here I recommend that you read about the basics of measuring loudspeakers. There's even a decent German translation of D'Appolito's book:

D'Appolito "Lautsprecher-Messtechnik"

Bye for now.

I am sure, when i measure in my room a good speaker, that it can have same less GD as a headphone. but to see what can be a good speaker for ITD i need see group delay or step response for pre choice. Of course i like see Group delay from the klippel and i do not tell that my measure are perfect. But they are at least good enough to show lots diffrence and all smaller speakers i have, are faster and more precise and sound better. and the measure precision that is possible in my room can see on headphone. When the speaker measures come near to headphone only then can say. maybe the mesure is not good.
 

markus

Addicted to Fun and Learning
Joined
Sep 8, 2019
Messages
646
Likes
653
I am sure, when i measure in my room a good speaker, that it can have same less GD as a headphone. but to see what can be a good speaker for ITD i need see group delay or step response for pre choice. Of course i like see Group delay from the klippel and i do not tell that my measure are perfect. But they are at least good enough to show lots diffrence and all smaller speakers i have, are faster and more precise and sound better. and the measure precision that is possible in my room can see on headphone. When the speaker measures come near to headphone only then can say. maybe the mesure is not good.
You're still confusing cause and effect and this is because you refuse to learn the very basics of the topic you want to talk about.
 
OP
B

bennybbbx

Addicted to Fun and Learning
Joined
May 27, 2020
Messages
691
Likes
124
Location
germany
You're still confusing cause and effect and this is because you refuse to learn the very basics of the topic you want to talk about.

and what is your argument wy on my measure the headphones get much better as the speakers ?. the JBL have a front grill. the kali not. I measure the kali in last measure more near inside the cone. does also not change the result. knowledge of theorie make not an expert. an expert is somebody who do practice measure lots speakers and know how much % the theoretic facts have influence to the measured results.

to avoid more factless writing from you i explain this. I hope you stop then your factless write

Wy you not save your time. nothing is 100% perfect i know this.. if you only bash me that i miss knowledge convinced not clever people that you are right. because this sentence

You're still confusing cause and effect and this is because you refuse to learn the very basics of the topic you want to talk about.

also flat earth believer can say to people that dont believe that the earth is flat same. did you not know the wise words ?

Insults are the arguments of those who are wrong
 
Last edited:

markus

Addicted to Fun and Learning
Joined
Sep 8, 2019
Messages
646
Likes
653
and what is your argument wy on my measure the headphones get much better as the speakers ?. the JBL have a front grill. the kali not. I measure the kali in last measure more near inside the cone. does also not change the result. knowledge of theorie make not an expert. an expert is somebody who do practice measure lots speakers and know how much % the theoretic facts have influence to the measured results.

to avoid more factless writing from you i explain this. I hope you stop then your factless write

Wy you not save your time. nothing is 100% perfect i know this.. if you only bash me that i miss knowledge convinced not clever people that you are right. because this sentence



also flat earth believer can say to people that dont believe that the earth is flat same. did you not know the wise words ?
You don't produce valid measurements and I explained some of the fundamental issues above. Others have done the same in other threads. And, the measurements you produce don't show what you claim they would ("speaker is fast enough for ITD" – a totally absurd statement). It has been explained to you multiple times why and I don't think it does help in any way to repeat it again and again. You're obviously not here to learn otherwise you would have read at least some of the references that were suggested to you.
 
Last edited:
OP
B

bennybbbx

Addicted to Fun and Learning
Joined
May 27, 2020
Messages
691
Likes
124
Location
germany
You don't produce valid measurements and I explained some of the fundamental issues above. Others have done the same in other threads. And, the measurements you produce don't show what you claim they would ("speaker is fast enough for ITD" – a totally absurd statement). It has been explained to you multiple times why

how would you know that my measurements are not valid. have you measure them ?. there is more between valid 100% and not valid possible 0%. all measure have a meaasure error in %. I admit that my measure have maybe 20% measure error. but when do several measures this overall error rate can decrease too. also i do only compareable measures. and when i measure in 1 speaker 140% more then a messure error of 20% is negliable in compare.

and with this error rate can still see, that the kali have much more Jitter in group delay and a slow looking step response as my other speakers.

maybe read about this.
Observational error (or measurement error) is the difference between a measured value of a quantity and its true value.[1] In statistics, an error is not a "mistake". Variability is an inherent part of the results of measurements and of the measurement process.

Measurement errors can be divided into two components: random error and systematic error.[2]

Random errors are errors in measurement that lead to measurable values being inconsistent when repeated measurements of a constant attribute or quantity are taken. Systematic errors are errors that are not determined by chance but are introduced by an inaccuracy (involving either the observation or measurement process) inherent to the system.[3] Systematic error may also refer to an error with a non-zero mean, the effect of which is not reduced when observations are averaged.[citation needed]

room influence can see as random errors when measure at diffrent positions. but i get on diffrent positions very simular results, so this confirm that room influence is less.
 

markus

Addicted to Fun and Learning
Joined
Sep 8, 2019
Messages
646
Likes
653
how would you know that my measurements are not valid. have you measure them ?. there is more between valid 100% and not valid possible 0%. all measure have a meaasure error in %. I admit that my measure have maybe 20% measure error. but when do several measures this overall error rate can decrease too. also i do only compareable measures. and when i measure in 1 speaker 140% more then a messure error of 20% is negliable in compare.

and with this error rate can still see, that the kali have much more Jitter in group delay and a slow looking step response as my other speakers.

maybe read about this.


room influence can see as random errors when measure at diffrent positions. but i get on diffrent positions very simular results, so this confirm that room influence is less.
How can I tell your measurements aren't valid? Because of the way you're doing them and how you try to make the results fit your completely absurd theory of "speaker is fast enough for ITD". Again, D'Appolito "Lautsprecher-Messtechnik". Read it.

So my current recommended reading list for bennybbbx is as follows:

- Howard/Angus, "Acoustics and Psychoacoustics"
- D'Appolito "Lautsprecher-Messtechnik"
- Toole, "Sound Reproduction"

Also recommended:
- Dickason, "Lautsprecherbau"
- Everest, "Master Handbook of Acoustics"
 
Last edited:
OP
B

bennybbbx

Addicted to Fun and Learning
Joined
May 27, 2020
Messages
691
Likes
124
Location
germany
How can I tell your measurements aren't valid?

you want say my mesaures are 100% wrong ?. then you need explain. When my measures are 100% wrong wy are the measure results duplicatable and diffrent measures on diffrent places show near same results. also with diffrent volume. when my measures are 100% wrong then the measure should be diffrent results. sometimes kali look faster sometimes not. but i always get same result. kali is the slowest with the most Jitter in group delay

Have you measure speakers ?. then show your results in group delay. then measure as i do and compare and post the diffrence. iam sure the diffrences are not much.

I have verify my measure with diffrent volumes. look near same on kali. so this is another confirm that my measures are not so worse as you want tell. show your better group delay messures and which speaker this is. and when i put another speaker on same position then it should produce same results. when it produce on this position better results then speaker is better worser results speaker is worser

same gd on kali.jpg
on diffrent levels.jpg
 
Last edited:

markus

Addicted to Fun and Learning
Joined
Sep 8, 2019
Messages
646
Likes
653
you want say my mesaures are 100% wrong ?. then you need explain. When my measures are 100% wrong wy are the measure results duplicatable and diffrent measures on diffrent places show near same results. also with diffrent volume. when my measures are 100% wrong then the measure should be diffrent results. sometimes kali look faster sometimes not. but i always get same result. kali is the slowest with the most Jitter in group delay

Have you measure speakers ?. then show your results in group delay. then measure as i do and compare and post the diffrence. iam sure the diffrences are not much.

I have verify my measure with diffrent volumes. look near same on kali. so this is another confirm that my measures are not so worse as you want tell. show your better group delay messures and which speaker this is. and when i put another speaker on same position then it should produce same results. when it produce on this position better results then speaker is better worser results speaker is worser

View attachment 172265View attachment 172266
Your measurements aren't valid for what you want to show. In fact there's no measurement that could help showing what you want to show namely "speaker is fast enough for ITD" as the whole concept is just a major misconception of yours.
 
Last edited:
OP
B

bennybbbx

Addicted to Fun and Learning
Joined
May 27, 2020
Messages
691
Likes
124
Location
germany

dualazmak

Major Contributor
Forum Donor
Joined
Feb 29, 2020
Messages
2,823
Likes
2,951
Location
Ichihara City, Chiba Prefecture, Japan
Hello OP @bennybbbx,

I just came across with this interesting thread.

I recently developed my own primitive DIY methods having 0.1 msec accuracy for measuring and adjusting the group delay, or better to say "time alignment", between the multiple SP drivers in multichannel multi-driver multi-amplifier stereo system;

Your visits, comments and suggestions on my thread will be much welcome;

- Precision measurement and adjustment of time alignment for speaker (SP) units: Part-1_ Precision pulse wave matching method: #493
- Precision measurement and adjustment of time alignment for speaker (SP) units: Part-2_ Energy peak matching method: #494
- Precision measurement and adjustment of time alignment for speaker (SP) units: Part-3_ Precision single sine wave matching method in 0.1 msec accuracy: #504, #507
 
Top Bottom