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Review and Measurements of Lyngdorf RoomPerfect EQ

Olli

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#42
Great review as always Amir, thanks!

I have the same experience wrt DSP being the most effective but also efficient measure for creating a significantly greater listening experience.

The next biggest improvement to my system was adding 2 subs (much better with Audiolense and a MC DAC) - and I have really big floorstanders myself. So defintely worth trying to integrate your Baby Sub!
 
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MZKM

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#44
I especially picked it to be thick to eliminate floor bounce and to reduce RT60.
You may know this, but others might not, an actual RT60 measurement should not be used in residential spaces, it is not simply a 60dB decay; here’s a Reddit discussion on the topic:
https://www.reddit.com/r/audiophile/comments/9aeb7m/_/e4vz5xe
A waterfall plot would be more telling, and as you likely aren’t using >100dB test tones (so that a 60dB decay is still above the room’s noise floor), instead look at the time it takes to do a 30dB decay and multiply that by 2.
 
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Juhazi

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#45
^For example REW does not even show actual T60, but EDT, T20 and T30 and something called Topt, etc.
Most rooms have noise floor around 30-40dB in daytime. 95dB sweep is OK.
https://www.roomeqwizard.com/help/help_en-GB/html/graph_rt60.html#top


Like said above, other visualizations and calculations are more helpful, like decay and spectrogram of decay, but they are not numerical.
This is nice, the wavelet spectrogram
 
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Krunok

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#46
I wonder according to which criteria alghorithm didn't try to correct that dip at app 180Hz.

I also didn't expect those speakers to have dip of almost 10dB at app 720Hz. That one is way above Schroeder frequency so it shouldn't have anything to do with room.
 

MZKM

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#47
I wonder according to which criteria alghorithm didn't try to correct that dip at app 180Hz.
That’s a 25dB dip due to SBIR, that would require 315x the current wattage to fix (only real fix is bass traps behind the speakers. It probably won’t correct decently high-Q dips, even at ~60Hz you can see the corrected response looks similar in shape to the uncorrected response.
 

Krunok

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#48
That’s a 25dB dip due to SBIR, that would require 315x the current wattage to fix (only real fix is bass traps behind the speakers. It probably won’t correct decently high-Q dips, even at ~60Hz you can see the corrected response looks similar in shape to the uncorrected response.
Dip at 180Hz is app 10db, not 25. It could be easilly corrected with a Q of say 20, which I don't see as a problem at 180Hz.

I agree, algorithm applied low Q to correct a dip at 63dB and it did that right in my opinion. But I don't understand why it didn't try to corrrect that dip at 180Hz.
 

MZKM

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#49
Dip at 180Hz is app 10db, not 25. It could be easilly corrected with a Q of say 20, which I don't see as a problem at 180Hz.

I agree, algorithm applied low Q to correct a dip at 63dB and it did that right in my opinion. But I don't understand why it didn't try to corrrect that dip at 180Hz.
Sorry, duh, meant ~13dB (assuming 1kHz should be raised a bit to 100dB), which is still 20x the current wattage.
 
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Krunok

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#50
Sorry, duh, meant ~13dB (assuming 1kHz should be raised a bit to 100dB), which is still 20x the current wattage.
If it managed to raise the dip at 63Hz by 10dB why do you think it wouldn't be able to do the same at 180Hz?
 

Krunok

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#52
It didn’t really raise the dip itself that much, it raised the general region.
OMG M8, we already agreed that it used the lower Q, but that was NOT the point of my question.

Don't you understand what am I asking in my previous post?
 

MZKM

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#53
OMG M8, we already agreed that it used the lower Q, but that was NOT the point of my question.

Don't you understand what am I asking in my previous post?
Because you asked why it didn’t correct the 180Hz dip but did the ~60Hz dip, and as you stated you agreed about the low-Q, that’s why I’m confused. It didn’t really correct the ~60Hz dip because of the Q-factor, but the entire region around it was also low so it raised that, the dip around 180Hz is by itself, the region around it is where it should be.
 
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amirm

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#54
Can you please clarify in more detail how you got this graph? Did you make a sine sweep from a single position with both speakers playing and then applied 1/12 smoothing?
Correct. You see the mic position in the picture. As I stated, normally I take measurements from one speaker a time. I meant to do that but only remembered after I had done all the graphs.
 

amirm

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#55
How many measurements did Roomperfect require and how large was the area you covered when moving mic between measurements?
From memory I think it was 5 or 6. First one was at the main seating position. For others, it says to pick random positions and I did that. One was to left of listening space, one between speakers, one further out and another to the right. I did not go behind the seating position.

As I noted, there is a percentage number shown after every random measurement. The recommendation is to get it up above 90%. On the last position recommended by the software it achieved 93% and gave me a choice to finish the measurements and that is what I did.
 

amirm

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#56
Thanks and nice to see your gear and room. I agree 100% to what you say about room correction benefits. Have you ever considered to simplify your system with active speakers that have a built in DSP room correction?
No because I am very happy with the system that I have. :) We have JBL Synthesis M2 at work and it sounds great there. I have thought about deploying that in our theater but we don't use that room to make it worthwhile to spend the money. For 2-channel listening, the Revel Salon 2 is so nice that I am left with no wishes for more.
 

Juhazi

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#57
Most microphones that we use and the ones for room measurements, are omnipole. Most manufacturers give eq curves for on-axis and 90¤, but difference is minimal. So is the difference in long IR gating measurements with the mic pointing at ceiling or speaker.

Eq'ing sharp dips is not possible or wise. They come from destructive interference/reflections, and the higher signal is, the higher is also reflected spl, resulting in null again, but if we move the speaker of mic, the dip's frequency changes moves and we have a huge bump in response.

The 720Hz dip is most likely a first reflection too - sofa or laptop or even side wall. The source is easy to find and fix by doing several measurements by moving mic, furniture, speaker etc. one per time. It also might be L/R comb filtering because both speakers were playing in the measurement.

The general (or better, majestetical) rule #1 is - thou shall not try to eq sharp dips in response!
umik-1 cal 0 vs 90 spl.jpg
 
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amirm

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#58
Here's how it looks with my room and speakers, all graphs are with 1/12 smoothing.
Thanks for posting those but you shouldn't set the bottom of the graph to 0 dB. That is the quickest way to artificially make the graph flat. :) Noise floor in your room is at least 30 dB so you want it at least that high. Comparing REW graphs is impossible if scales are not the same.
 

Krunok

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#59
Thanks for posting those but you shouldn't set the bottom of the graph to 0 dB. That is the quickest way to artificially make the graph flat. :) Noise floor in your room is at least 30 dB so you want it at least that high. Comparing REW graphs is impossible if scales are not the same.
Oh, you're right, I wasn't thinking about that. And yes, noise is app at 30dB, even higher at both ends of the audible spectrum.
Here is a better scaled graph..

 

amirm

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#60
Eq'ing sharp dips is not possible or wise.
In theory that is true. In practice I have managed to make some improvement because the dips are not 100% cancellations. I go slow and only dial up a dB or two while listening at the same time.
 
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