How to interpret REW graphs

[Love4sound]

I guess it’s safe to assume a few members are good with rew and we have a handful number of rew users. Most discussions on rew we only look or discuss about SPL graph. However other graphs like waterfall,decay and spectrogram isn’t discussed much. If any clear article available please share. I generated them but have no idea how to interpret them. If any one is aware please explain. I have shared all 3 for my front and rear subs. How bad is it? Treatable bad or untreatable bad?

 

[liverpool_for_life]

Please post spectrogram of the combined response of your subs at the MLP. That's what you hear/feel. Effective passive room treatment is going to be really hard down in this range because of the large wavelengths involved. Your best bet is to manipulate delays to get rid of nulls and use EQ to tame the peaks.

 

[Love4sound]

Please post spectrogram of the combined response of your subs at the MLP. That's what you hear/feel. Effective passive room treatment is going to be really hard down in this range because of the large wavelengths involved. Your best bet is to manipulate delays to get rid of nulls and use EQ to tame the peaks.

Please find the combined graphs.This is not with EQ. I only understand we use these graphs to analyse the ringing and decay but no clue on how to interpret the graph.

 

[Love4sound]

These graphs are after eq and audyssey

 

[liverpool_for_life]

You have a fairly problematic peak in the mid-late 40 Hz range. There's a couple in the mid-teens and mid-20's as well that really ought to have been EQ'd out. It also looks like you've got a fairly wide null past 70 Hz. Can you post your combined FR, with and without EQ?

 

[sud98]

I am assuming the 48 Hz peak coincides with one of your room modes. Is that correct?

 

[Love4sound]

You have a fairly problematic peak in the mid-late 40 Hz range. There's a couple in the mid-teens and mid-20's as well that really ought to have been EQ'd out. It also looks like you've got a fairly wide null past 70 Hz. Can you post your combined FR, with and without EQ?

Sure will post them later. Currently I am dealing with some other issues which I need to rectify

I am assuming the 48 Hz peak coincides with one of your room modes. Is that correct?

I am not sure how to interpret those graphs so unable to answer your question

 

[RajithKumar]

I guess it’s safe to assume a few members are good with rew and we have a handful number of rew users. Most discussions on rew we only look or discuss about SPL graph. However other graphs like waterfall,decay and spectrogram isn’t discussed much. If any clear article available please share. I generated them but have no idea how to interpret them. If any one is aware please explain. I have shared all 3 for my front and rear subs. How bad is it? Treatable bad or untreatable bad?

From what I understand is Waterfall is a 3d representation of decay time for the frequency range measured. Using this ,one can able to find out the standing waves problem and it's decay time ,and can able to take a call on its treatment ( either passive or active) depending upon the frequency range.
Decay is 2d representation.
Spectogram is the plan view of decay time for frequency measured.

 

[Love4sound]

You have a fairly problematic peak in the mid-late 40 Hz range. There's a couple in the mid-teens and mid-20's as well that really ought to have been EQ'd out. It also looks like you've got a fairly wide null past 70 Hz. Can you post your combined FR, with and without EQ?

First graph has response for subs without eq. Red is combined, yellow is rear sub. 2nd graph is Post eq and audyssey.

From what I understand is Waterfall is a 3d representation of decay time for the frequency range measured. Using this ,one can able to find out the standing waves problem and it's decay time ,and can able to take a call on its treatment ( either passive or active) depending upon the frequency range.
Decay is 2d representation.
Spectogram is the plan view of decay time for frequency measured.

yes I understood the part where waterfall is the 3d representation for decay time, Decay graph is the 2d representation. Just not sure how to interpret it and what is considered to be normal

 

[RajithKumar]

First graph has response for subs without eq. Red is combined, yellow is rear sub. 2nd graph is Post eq and audyssey.

yes I understood the part where waterfall is the 3d representation for decay time, Decay graph is the 2d representation. Just not sure how to interpret it and what is considered to be normal

What I heard is if the decay time is between 300ms to 500ms ,the bass will be superb.
Practically it's difficult to do passive correction via Treatment for frequency below 80 hz .You may need to tame it using active correction.
The important thing is planning of room , placement of speakers ,passive treatment and finally active calibration.

 

[sud98]

I am not sure how to interpret those graphs so unable to answer your question

USe the room mode calculator using this https://amcoustics.com/tools/amroc and check the room modes that you have. Most likely, you will find one of the dimension having this frequency. Which also means with two subs positioned properly along the axis you could cancel them.

 

[Love4sound]

USe the room mode calculator using this https://amcoustics.com/tools/amroc and check the room modes that you have. Most likely, you will find one of the dimension having this frequency. Which also means with two subs positioned properly along the axis you could cancel them.

Sure will check this out later. I am now caught with another issue with one of my sub and waiting for a resolution. Once done I will get back to alignment and integration

Identical subs with different frequency response, time domain and SPL

I have dual LV12F and ran into a problem with one sub. Both subs at same location and gain values are having a different frequency response, gain and delay values.Reached rythmik support who acknowledged this is not normal and have agreed to ship a new amp from us. So to explain in detail about...

www.hifivision.com

 

[Love4sound]

You have a fairly problematic peak in the mid-late 40 Hz range. There's a couple in the mid-teens and mid-20's as well that really ought to have been EQ'd out. It also looks like you've got a fairly wide null past 70 Hz. Can you post your combined FR, with and without EQ?

The Identical subs with different frequency response issue is resolved. Got my sub replaced and turns out one unit was faulty. Please find the requested graphs. Blue is the combined response of both subs. Black is after EQ using mini DSP. Yet to run audyssey.

 

[liverpool_for_life]

Black is after EQ using mini DSP.

Not bad, actually. No massively deep nulls to worry about. The rise below 40 Hz might be enjoyable for movies. How does it sound?

Yet to run audyssey.

Please do.

 

[captainsubtext]

Not bad, actually. No massively deep nulls to worry about. The rise below 40 Hz might be enjoyable for movies. How does it sound?



Please do.

Wouldn’t you set up a house curve on mini dsp and skip audessey altogether for the subs?

 

[Love4sound]

Not bad, actually. No massively deep nulls to worry about. The rise below 40 Hz might be enjoyable for movies. How does it sound?

The rise below 40hz is due to me setting up the house curve using mini dsp. Yet to test and still experimenting to integrate it with the mains

 

[liverpool_for_life]

Wouldn’t you set up a house curve on mini dsp and skip audessey altogether for the subs?

That works too and is apparently what the OP did. AIUI, Audyssey’s approach to integrating multiple subs is questionable. So, any integration work prior to presenting Audyssey with a combined response is preferred.

 

[Love4sound]

That works too and is apparently what the OP did. AIUI, Audyssey’s approach to integrating multiple subs is questionable. So, any integration work prior to presenting Audyssey with a combined response is preferred.

Guess in my case audyssey is doing a good job with dual sub integration. The response is almost identical. I connected both subs directly to the avr removing mini dsp from the chain. In the 1st image blue graph is the sub response after AVR calibration and the red is using mini dsp and post audyssey. Now my problem is integration. For example if i set a sub distance and integrate it with mains the same value is having phase issues for center. This issue i am having with both AVR and mini dsp. In the second image the purple graph is mains crossed over at 90 and orange is center crossed over at 100 for the same sub distances set.

 

[Love4sound]

Deleted

 

[Naveenbnc]

The Identical subs with different frequency response issue is resolved. Got my sub replaced and turns out one unit was faulty. Please find the requested graphs. Blue is the combined response of both subs. Black is after EQ using mini DSP. Yet to run audyssey.

Hey ....are you not loosing lot of energy ?? Just for eliminating the nulls it looks like you reduced the overall SPL. May be you can target the graph 5-6 db more and still live with some minor nulls here and there ...