Another tool to add to your REW toolbox is the MMM type of measurement which can give you a better idea of what's happening and will often smooth a response but still show offending dips and peaks that correspond with static sweeps. Stationary mic positions only give you information about that particular point in space and time which, as demonstrated above, will change in another mic location. I use both methods when trying to dial in my speakers.
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How to look for room modes in REW measurements
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ZolaIII
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Oddest setup I ever saw. A floor sitting bulldogs run trough mobile. Neutron dose still have best PEQ, especially graphic presentation on mobile but that's about it. Last time I played with it it whose still somewhat buggy and unstable. How about using PC and EQ-APO? It even has loudness (ISO 226 2003).
ZolaIII
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When I move around the hause I DLNA stream local or use standard online streaming services to stream on my phone. When working out I am too lazy even for that and listen to FM on IEM's.
APO has PEQ and REW can export to it directly, also has plugin suport (for convolver, phase and such), EBU R128, and Loudness. It's free, can be quirky from time to time. Acts as WDM intermediate driver (Windows) and can be inserted in between of almost anything with exception of those apps that have their own separate no access final output (DRM and such). I am on JRiver which is not free and works is similar means but has its own extras (properly decoders and such).
ZolaIII
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Yes. You can do adjustments to measured SPL by hand. JRiver - EQ APO loudness works on pre withe noise calibration and trough their own volume controls afterwards.
er|κzvio1in
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Me too, I use both, the disadvantage of using MMM is that it doesn't give you phase information.
ZolaIII
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Naaa, you get used to it. JRiver has 100 steps 0.5 dB step. I do it remotely (Jremote2, wireless keyboard with deticated scroll wheel or trough mause). Amplifier stays at reference 100 point (88 dB SPL A) calibrated so it can't go over that and demage speakers. I usually start listening at 76 (-12 dB or 76 dB) and it firmly stays like that.
This is wrong, isn’t it? A room mode has a well defined frequency. If we are in a null of this mode, we measure a dip at this frequency. If we move away from the null, we will get a shallower dip, which will stay at the same frequency. Correct me if I’m wrong.
Keith_W
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Rooms don't form modes in only one frequency, there are many. Suggest you play a bit with the REW room simulator. Set the speakers and subs in one position, then move the MLP around. You will observe the same pattern that I described
ZolaIII
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It's fundamental refraction frequency in low bass/sub bass determined by length of the room mostly (where it will be) that propagate having two main additional harmonics. If you deal most partly with fundamental following two peeks and first three deeps also become proportionally smaller. It's possible even to completely eliminate it in near field putting sub directly in front of you at about 1 m distance (and at about middle of the room). Play with REW room simulator it will show you (and anyone else) all you need to know.
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theREALdotnet
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I agree. Room modes are a result of room geometry and their frequencies are independent of speaker or listener position. You can excite them or avoid them by moving speaker or listener, but you cannot change their frequency. It is possible (quite common actually) that room mode frequencies sit close to each other, so by moving the listener you may avoid the trough of one but end up in the trough of another.
SBIR, on the other hand, is determined by the distance between speaker and solid surface (wall, floor). The extinction frequency is where that distance is a quarter of the wavelength.
ZolaIII
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Point is you don't have to listen very loud, nor you can most of the time and all of that shouldn't be a limiting factor and there for equal loudness compensation.
I have deticated AV room, isolated from rest of the hause, good and not many neighbors and I still don't listen too loud most of the time. Try to start at low 70`s average and end at high 70's most of the time (average A scale SPL and with bass peek limit of +20 dB in addition to loudness enchantment). Sometimes I crunch it up all the way to 88 dB but not so often, even for electronic bass dominant and real kick feeling low 80`s is enough. Sensation doesn't last very long (usually about 30 min) so it's better to start up one level lower (1.5 dB) and end up 1.5~2 h later two levels up from initial wow SPL feeling.
Bow_Wazoo
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Yesterday I watched this video. I wasn't aware, that there are other options, beyond the FR correction with a PEQ...
ZolaIII
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There are of course. Please disregard boost threshold from target curve inversion FIR (second filter). It should be much lower (and same as for PEQ in REW) about +2 dB max not +5 as much as I recollect is in the video.
Edit: first two filters are the main, especially first one VBA and that you enable it before doing anything else. It's same as putting in a bass trap (Helmholtz resonator). So you first do that (enable it) then do PEQ-ing and enable it and only then bake another FIR with (same) VBA and target curve inversion. After all that in place you eventually additionaly slope highs with cuple wide (low) Q PEQ's if need be.
If you need good low latency convolver plugin you have MConvolutionEZ (in cumulative pack with MFreeformPhase and cetera) in free edition.
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Bow_Wazoo
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Yes, I will start all over again.
Just because of the fact that I get new speakers at the end of the week.
I will first measure the FR, and then correct it with the PEQ, and then work on the FIR filters.
Edit: got it. First 2 filter first. Especially VBA.
I don't know yet whether I will switch to streaming via PC (to have Loudness Correction). I would like to stay with the smartphone.
I found an interesting app: Rootless JamesDSP. In combination with Deezer, it should be a step forward.
As far as the setting of the boost in Rew is concerned, I saw yesterday in a video that it is advised, to leave it at 0dB, because it makes physically no sense, to give energy in room modes.
As far as I have learned, the current REW version prevents this anyway.
I'm just wondering if Rew can then calculate PEQ settings, to reach my Harman target?
Just because of the fact that I get new speakers at the end of the week.
I will first measure the FR, and then correct it with the PEQ, and then work on the FIR filters.
Edit: got it. First 2 filter first. Especially VBA.
I don't know yet whether I will switch to streaming via PC (to have Loudness Correction). I would like to stay with the smartphone.
I found an interesting app: Rootless JamesDSP. In combination with Deezer, it should be a step forward.
As far as the setting of the boost in Rew is concerned, I saw yesterday in a video that it is advised, to leave it at 0dB, because it makes physically no sense, to give energy in room modes.
As far as I have learned, the current REW version prevents this anyway.
I'm just wondering if Rew can then calculate PEQ settings, to reach my Harman target?
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ZolaIII
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It doesn't have sense in room modes but it does in case of not great (95%) crossovers to even out the deep as much as speakers can take it (1~2 dB 3 at most and only with some speakers that much).
Also in combination of phase correction to give more by better sum.
REW will anyway try to avoid the boost when it can (if set conservative as explained).
Also in combination of phase correction to give more by better sum.
REW will anyway try to avoid the boost when it can (if set conservative as explained).
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