Room acoutics issue 300-3000Hz

[Thomas_A]

Hi
The Mic was placed at the same height at the midrange driver which was 1m when standing on the floor

Here is a measure from a Dali Rubicon LCR, elevated 50 cm, 1m distance, gated at 1-5ms, standing at the same spot. its a much smaller speaker though.
View attachment 186085

You have some comb filltering issues during measurenemt but the Dali looks as if it does not have the dip.

 

[DJBonoBobo]

The Evoke 50 has crossover frequencies at 430 and 3500 Hz. Maybe there is an an issue with the mid driver? I don't know but maybe worth checking.

 

[Thomas_A]

It appears the same for both speakers. I’ve not seen measurements of the 50 model but the 30 model do have a dip 1-2 kHz. Not as large as this.

However there is still some comb filtering issues as seen from the Dali. Needs to be measured on axis away from walls and objects. Should not look like that with gating applied.

 

[ChristianN]

It appears the same for both speakers. I’ve not seen measurements of the 50 model but the 30 model do have a dip 1-2 kHz. Not as large as this.

However there is still some comb filtering issues as seen from the Dali. Needs to be measured on axis away from walls and objects. Should not look like that with gating applied.

agree, i will find another AMP that I can actually carry, and do an outside measurement tomorrow og both speaker

 

[ChristianN]

The Evoke 50 has crossover frequencies at 430 and 3500 Hz. Maybe there is an an issue with the mid driver? I don't know but maybe worth checking.

Hmm yes, that sounds very plausible, I also tried to send a sine-tone and turn it up slow, when it hit approx 400 at 80Db the speaker makes a wierd mechnical off-sound. so that would be when the midrange takes over

 

[puppet]

Hmm yes, that sounds very plausible, I also tried to send a sine-tone and turn it up slow, when it hit approx 400 at 80Db the speaker makes a wierd mechnical off-sound. so that would be when the midrange takes over

Looks like you've eliminated the room as the issue I'd think.
Shouldn't be able to hear the mid "take over". It's also strange that both loudspeakers share this anomaly.
What does your measurement signal chain consist of? Mic on a boom or??
Does your amp have any tone controls enabled?
Possible to see the loudspeakers crossover network?

 

[ChristianN]

Looks like you've eliminated the room as the issue I'd think.
Shouldn't be able to hear the mid "take over". It's also strange that both loudspeakers share this anomaly.
What does your measurement signal chain consist of? Mic on a boom or??
Does your amp have any tone controls enabled?
Possible to see the loudspeakers crossover network?

Hi
I just made some new outside measuremets in the other post here.
As for the measurent the mic is stading on a little ladder, this time around approx middle of the drivers. The mic goes directly to the laptop. There are no tone controls on AMP or Preamp, they simply dont have any. Im not sure what you mean with the crossover, is that to take the crossover filters out of the speaker?

 

[ChristianN]

agree, i will find another AMP that I can actually carry, and do an outside measurement tomorrow og both speaker

Ok so did a ton of measurement, used a new integrated amp.
Outside gated 1 m away. is a better respons no doubt, everything is keept the same. 'The dip' is markedly better outside.

I also tried to bypass the preamp. use the original Amp and all combinations of using digital direct or analog signal from laptop, i will not show them as they show no difference really. So it kind of rules out that amp or preamp or DAC is faulty.

I also tried to place the speaker outside in the garden, 1m from the house and right up against it, ported the speaker, it does not change the response curve ( in regards to the dip ) only add more jitter and minimal bass extention, but no real diff..

The result puzzles me a bit. It clearly better outside but also far better inside than the orignal measures just 2 days ago. The dip is better in both cases, using the exact same components. The only change is that I did use the speaker a LOT for measure and listening also very loud, not sure if that would be able to fundamentally cause such a change though.

So i also did a new in room in place measure, and that is also much differencet, is has some huge dips, that can be blamed on the room, but not the whole 400-4000 dip?
Not sure how that happended?

 

[DJBonoBobo]

So i also did a new in room in place measure, and that is also much differencet, is has some huge dips, that can be blamed on the room, but not the whole 400-4000 dip?
Not sure how that happended?
View attachment 186370

This actually looks quite good now, imho. Does it sound better than before?

The scale only covers 25dB, which makes it look worse than it is. Most common is covering 50 or 60dB and using var smoothing. Personally, I think i would probably only lower the bass by EQ between about 70 and 175Hz. The dip at 400Hz can be anything, possibly front wall, TV, ceiling or floor.
I would recommend to do another MMM measurement now. Maybe then the dip at 1.5khz disappears.

 

[Thomas_A]

Ok so did a ton of measurement, used a new integrated amp.
Outside gated 1 m away. is a better respons no doubt, everything is keept the same. 'The dip' is markedly better outside.

I also tried to bypass the preamp. use the original Amp and all combinations of using digital direct or analog signal from laptop, i will not show them as they show no difference really. So it kind of rules out that amp or preamp or DAC is faulty.

I also tried to place the speaker outside in the garden, 1m from the house and right up against it, ported the speaker, it does not change the response curve ( in regards to the dip ) only add more jitter and minimal bass extention, but no real diff..

The result puzzles me a bit. It clearly better outside but also far better inside than the orignal measures just 2 days ago. The dip is better in both cases, using the exact same components. The only change is that I did use the speaker a LOT for measure and listening also very loud, not sure if that would be able to fundamentally cause such a change though.

View attachment 186360

So i also did a new in room in place measure, and that is also much differencet, is has some huge dips, that can be blamed on the room, but not the whole 400-4000 dip?
Not sure how that happended?
View attachment 186370

Can you plot your original measure in room and your latest one in the same diagram? 50 dB scale, same gating and same smoothing? Left speaker would be sufficient.

 

[ChristianN]

Can you plot your original measure in room and your latest one in the same diagram? 50 dB scale, same gating and same smoothing? Left speaker would be sufficient.

Hi Yes
The Green is the reference outside measure gated
The Oranges are L and R gaited in place, from 1m
The Blue is the before measure at LP
The Red is the current measure at LP

So, red shows a less dramatic high freq boost, hence is all seems more liniar, the sub 200Hz is more easily handled by DSP. There is still a boost at 8-12K which I also saw on the ref measure outside, allthough more prononced here.
The individual measures shows the dip is very much still there.
How does it sound, well better, more midtone, and the high notes i dont hear as not much music i have use up to 12K. But as I know the graph it may affect the percieved sound.

I'm not sure what to conclude but it is not ideal, but not useless either. The ref measure of the speaker itself is "OK" and hence the room must be the source of the surprising boost in both lower and top end, which would call for dampning, any thought on this ?

 

[ChristianN]

This actually looks quite good now, imho. Does it sound better than before?

The scale only covers 25dB, which makes it look worse than it is. Most common is covering 50 or 60dB and using var smoothing. Personally, I think i would probably only lower the bass by EQ between about 70 and 175Hz. The dip at 400Hz can be anything, possibly front wall, TV, ceiling or floor.
I would recommend to do another MMM measurement now. Maybe then the dip at 1.5khz disappears.

Hi Yes it's seems better, here is an MMM measure, The dip is still there, not sure how big a dip is acceptable, i would think >6db is too much and if I apply 1/6 smothing, then the dip is close to 6db in LP. As the speaker seemed ok outside, i guess this means some sort of room alteration is the only way forward or DSP.