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Post by Hexspa on Jul 3, 2023 2:20:52 GMT
To find the source of a null, you first must find the wavelength of the frequency. You have an issue at 100Hz. The wavelength is 11.25'. Divide by 4 to get ~2.8' or 0.86m. It's likely that some reflective surface 2.8' from your monitors or microphone is causing this destructive interference. I assume your measurement is overlaid Left and Right so this boundary is equidistant to both monitors. The best thing is to move your monitors, the second best is to absorb the boundary. For 100Hz, you need 6" rigid, 12" safe n sound or 24" fluffy, each ideally gapped 1x thickness but the second and third options might not need it. You also have a touch of ringing around 120Hz. I've posted how to find your room's modal frequencies elsewhere on this forum. You can search for the formula if you need it. calculators.io/wavelength-to-frequency/Also, what's the time on that waterfall?
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Post by Hexspa on Jun 29, 2023 3:29:12 GMT
I recommend some bluetooth over-ear protection.
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Post by Hexspa on Jun 27, 2023 4:15:25 GMT
Hi, 1st of all if your room is a adequate dimension width and length ideally a rectangle, you'll be pointing your speaker down the length of the room yea...you first null occurs at 38% out from the end of the room that's listening position (where you rest your seat). Now say your console is 3 feet in depth and 5.5 feet in width...you most like be sitting about 4 feet out from the BACK of you console or where the shelf you place you speakers on. So say you put your speakers (woofers) about that 3 to 4 feet apart, that is the distance you should be sitting away from them...in the SWEET SPOT....basically you triangulate...you sit the same distance from them as the are apart from each other. If your room has been brought into balance with proper treatments, Bass traps corners (or so), low mids front and center of your desk (behind your listen position, speaker array) moving out from the corners more low mid traps till you on bot sides of your listening position should be treated so you are able to hear your mid range. Okay...so and so around you room with treatments the back wall could be pretty much what your front wall is...(bass traps corners and some low mid to deal with peaks that build up there) or may want to install QRD diffusion make room sound bigger and bring in the reflections you WANT so your rooms not to dead...clouds over your mixing position etc etc. Okay that's a rough outline for treatment...point being, you can get some pretty strange anomalies going setting up speakers if your room is not treated in reference to it's dimensions and the treatments you choose/apply. Every read Ethan's FAQ'S page....vital...here is the link to it below. You mention "sound-stage" I get it but I think the real terminology is the "free field". In the case of your project studio the free field is the room it's self. A free field is a region where the acoustic waves can propagate free from obstructions that would otherwise interfere with the sound path. How you go about apply treatments in your room will be everything to how you hear or achieve what you mentioned "Depth and Imaging". I have trained myself to listen to reflections in rooms, I have heard some of the weirdest anomalies that some people just don't notice, but the are apparent when listen back to your mixes, and how your mixes will translate outside of your mixing environment. Everything you want from your project studio you can achieve if you have a half decent room and have treated it properly...Sorry but in the end, we can run,but we can't hide on this LAW. Here is Ethan's FAQ'S page. You'll find his diagrams on best listening position here. ethanwiner.com/acoustics.htmlHi, shuggy22, welcome and thanks for helping out. I just want to clarify what you mean about "first null occurs at 38% out from the end of the room". While this axial length point has been suggested by noted Acoustics authority Wes Lachot, it's not because there's a null there. Indeed, he suggests it because he's reasoned it to be a point with balanced modal performance i.e. no severe nulls. To this end, let's clarify what we mean about "first null". In terms of time, and we're talking sub-63 milliseconds (1000ms/16Hz), It stands to reason that the "first null" will be the speaker-boundary interference response (SBIR) of any boundaries nearest the speaker followed by any half-way reflection between the speaker and the receiver (mic or listener) and then the periodic amplitude response pattern governed by the room's boundaries (primarily axial mode resonances) in the lowest frequencies below the Transition Frequency will produce nulls. It takes longer for the modal response to build because the wave cycles are slow i.e. you can't have a 20Hz resonance until there's 20Hz which takes 50ms to come into existence. In terms of frequency, the "first null" would occur at the center of the room, 50% the length, width and/or height. This is because the fundamental mode's wavelength is 2x each axial dimension. For example, a 16' length will produce a fundamental resonance with a wavelength of 32' and an SPL null at that frequency in the center of the room (but a velocity maxima which is inaudible). The same thing happens with each modal dimension then proceeds further up the frequency spectrum harmonically producing nulls at 1/4 and 3/4 dimensions (2nd harmonic), 1/6, 1/2, 5/6 (3rd harmonic), and 1/8,3/8,5/8,and 7/8 (4th harmonic). Like typical harmonic distortion, consideration of further harmonics is not a primary concern due to change in behavior of acoustic energy past the Transition Frequency. If we divide 3 by 8, we get 37.5% which is pretty close to Mr. Lachot's 38% recommendation. For this reason, I have been convinced by another acoustics professional, Mr. Grimani, that the better initial locations for a listening position are 20, 32 and 45% the LWH of the room. I say "initial" because considerations like surface absorption and hidden gremlins in the wall may influence the exact spot. Always measure to confirm. Hopefully this clarifies things. If I misunderstood you, please let me know. Thanks.
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Post by Hexspa on Jun 21, 2023 17:47:45 GMT
Energy Decay Curve (Schroeder's Integral) shows how much total energy is in the room at a given time. This is distinct from the Energy Time Curve which is the Impulse Response Envelope showing the discrete levels of individual reflections.
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Post by Hexspa on Jun 19, 2023 18:18:10 GMT
This is not my area of expertise but sound will go around things at low frequencies and bounce until it finds a way "around" your barrier. Plus any resonance the walls have will transfer through the structure to the other side and cause sound. I guess the absorbers will only transduce the sound that hits it whereas construction will prevent the energy from being transferred outside. Anything your absorption doesn't catch will be reflected or transferred into the structure and ultimately passed on to the outside. You're reducing total acoustic energy in the room but the minute it hits a boundary, that's where construction matters. That's my guess.
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Post by Hexspa on Jun 18, 2023 13:55:27 GMT
thinking it won't make any difference! Little do they know
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Post by Hexspa on Jun 16, 2023 15:34:20 GMT
All I know about sound isolation is that even small gaps reduce a barrier's acoustic performance significantly. For example, small gaps around a door can reduce its effect on blocking sound by, say, 25%. I don't know the exact ratios of gap-to-performance decrease but it's surprising how little will ruin the effect.
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Post by Hexspa on May 30, 2023 12:15:51 GMT
Thanks for the idea rock, I'll keep thinking of ways to mount my panels when they're finished. Ideally I'll be spacing them 8" off the walls. Also good point about the pro studio builds. I guess there really is no such thing as too much low frequency absorption. Cool to see your room and progress Hexspa! Glad to see this stuff does make a real difference. It's interesting that even a smaller desk can reintroduce nulls like those in your post-treatment graph, guess I'll have to swap out the big desk. Yes, I think it's a few things including the multi-tiered desk. It has the speaker riser that goes all the way across the front and doubles as a dual 19" rack so that's two levels plus I have a 27" monitor (though angled) and an 88-key midi controller between that and a QWERTY keyboard. Those nulls represent quarter wavelengths of under 2' so what else could it be? I'd love to remake this desk out of acoustically transparent material but, with all this other crap I don't know how much it would matter. I think in theory it should be fine to broadly boost the 2-300Hz range then raze off a few peaks, especially since my reference level is just 63dB but I'm going to change monitors at some point. If you look at the FR of these speakers, they're very boosted above 1kHz and that makes the lower midrange look scooped. I'm not trying to blame my gear but in this case it matters as far as I know; you mostly only want to EQ below the transition frequency and 300Hz is pushing it. Either way, if you look at the note-to-frequency values it's only like four notes that are sucked out (two per null) so I'm not that worried. But, yeah, nothing is ever perfect but we make the most of what we have. Sometimes that's resorting to headphones. EDIT: thinking about those lower midrange nulls, I may have left my stool next to the mic stand. My reasoning was probably "this is where it's going to be anyway" but once I wrap this room up, I'll have to remember to measure with and without.
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Post by Hexspa on May 30, 2023 12:08:25 GMT
Here's a neat artefact. All I know about this diffuser type is from the video Ethan made where he was strumming the hell out of an acoustic in front of one I briefly read what Mr. Volkmann wrote but he kind of lost me talking about the Philadelphia Academy of Music and how the paneling re-radiates sound. Like, ok but I can't see that from any pictures so whatever. What I think is interesting is how he recommends similar reverb times for listening rooms that later papers do. Anyway, here it is if you're looking for dump material: worldradiohistory.com/ARCHIVE-RCA/RCA-Broadcast-News/RCA-40.pdf You can delete "rca-40.pdf" and browse the directory of other issues.
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Post by Hexspa on May 19, 2023 22:42:32 GMT
Here's a shot from the rear right. From the left, you can see four 6" rigid panels which absorb a mini hall wall that borders the kitchen. Past those, you can see the rear corner of a 31.5" fluffy super chunk. These are doubled up to make 24" soffits. Continuing around, I'm actually missing about 24" worth of recording zone right now but past that you can see the 15"-wide, 12"-thick safe-n-sound panels made from vinyl drywall bead. If I was to do it again, I might use metal since the vinyl is a little wobbly. Continuing clockwise, there's a super chunk in the front left corner of the room gapped about 2'. Behind that is my subwoofer. The front wall is totally untreated and the right wall is a mirror of the left sans the rear panels. Let's not forget the cloud which I significantly enlarged from my last space. Instead of one 2x4' 4" cloud and then two more of those above my recording zone, we've done the entire studio area with 6" rigid, about 64ft2. Seeing others' results, I noticed that often those with the biggest clouds got the best results and I can confirm it's very helpful. There are about 6" gaps between the rigid panels due to us needing to mount them on joists instead of drywall due to weight. This is true for the recording zone and the RFZ monitoring zone. Since my speakers are less than 1m distance, I haven't noticed any negative effect on stereo imaging and the measured response of each is not drastically different. To reiterate, the listening position is about 45% the width and not centered. Subjectively, and backed by measurements, the bass is nice and solid here. Actually, the response is a little better about 1 foot behind my MLP but I'll just use that as an excuse to stretch my legs . I have a very thin carpet but that's mainly to damp my footsteps and other mechanical noise so my neighbors don't hear me as much. Probably doesn't really help but I like to pretend it does.
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Post by Hexspa on May 19, 2023 21:43:39 GMT
Zejamin, by all means explore the calculator. I've already done that work and came up with the ideal thicknesses per absorber type: 24" for fluffy, 12" for safe n sound, 6" for rigid - each with a 1x air gap. The reason 8" vs 12" safe n sound-equivalent shows little difference is due to a few things: your air gap is not 1:1 in both examples, you haven't selected random incidence (which you get when gapping a panel in a room), it's absorbing more from 20-40Hz which is a significant difference. For absorption coefficients, anything above 0.15 is significant and that just about meets that difference. The final reason, which doesn't apply here, is that beyond a certain thickness (per material, technically its gas flow resistivity), you end up with too great of a resistance and the panel becomes increasingly reflective. Essentially, you begin to put solid walls up. Here are the pre-eq response images of my room. I didn't take a sweep after EQ because I'm using Equalizer APO and I'm not sure whether the filters are going to affect the sweep and I didn't want to deal with it at the moment. Bass peaks are easily tamable with EQ and, subjectively, they're having their effect. The reason I boosted my subwoofer, which is causing that 20dB bass boost, is because I planned to EQ later and I wanted maximum level at the lowest frequency possible. In any case, impulse response envelope and decay are where the real battle happens so just imagine a semi-Harman bass-boost on the bottom instead of the gigantic bass peak. This is a non-smoothed response with both speakers and sub playing so, really, the SPL is very good. Impulse envelope should be around -10dB within 40ms ( Mellor) or -15dB within 20ms ( Winer), my decay target is -20dB above 63Hz within 150ms ( Spencer). Decay plot values are 140 and 160ms. For the heck of it, I'll post the predicted EQ curve too which is applied to an average of several measurements in about a 1' radius of my main listening position. The three nulls from 125-310Hz are probably from the desk. I will be adding 24"-thick fluffy soffits to the front and rear walls to tame the 60Hz resonance. Let me note that the speakers here are two Yamaha HS50 and the HS8s sub (the older one with a thru out). You can see from the EQ image that a few dB is shaved off at a higher frequency. This should be fine because the directivity of these speakers is pretty smooth which is what you look for when applying EQ to mains. Please see the Audio Science Review Spinorama-based review. Attachments:
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Post by Hexspa on May 19, 2023 21:35:28 GMT
Yeah, do that wherever possible (remove the drywall to expose the insulation). If not, you can search on here for Ethan-approved strategies for treating vaulted ceilings.
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Post by Hexspa on May 14, 2023 20:40:59 GMT
SPL is overrated! Focus on decay and minimizing reflections if you want accuracy. Minimize nulls through placement and then peaks through EQ.
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Post by Hexspa on May 11, 2023 19:56:51 GMT
Let me give it to you easy:
Larger room, forget 38%; go with 20, 32, or 45% - your choice (20% north side big room is probably best), use 6" rigid on ceiling, 12" safe n sound on side walls at 24"-thick front-and-rear walls. Treat windows like normal boundaries. Corners are just the convergence of surfaces and consequently 1/4 wavelengths. Other than that, they're not important (for speakers it's the same but for pressure instead of velocity which gives "room gain" but that's a different story).
That's how I have my room set up now and it's great. I was thinking about posting measurements but I want to get the extra 24" front-to-back dimension treated. I'm meeting or exceeding my targets 20dB decay within 150ms above 63Hz and energy time curve down at least 10dB within 40ms. Actually, I only have one remaining resonance at 60Hz which I'm assuming is front-to-back (easy to check but I just haven't) that exceeds that just by 3dB or so. With the 2' fluffy soffits, I'm sure that'll go away.
Keep it simple, you don't have to reinvent the wheel. I have 8 [edit: 12] 6" 4x2' panels [8 are cloud, 4 are rear], 12 12"-thick 15"x48" safe n sound side panels, nine 31.5"x48" fluffy superchunks (diagonal soffits) in the corners. If you do that, you'll get the result - guaranteed. Anything less and you're going to compromise. Actually, you get a little wiggle room but not too much. Like I said, try to do what I'm doing and you'll be happy.
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Post by Hexspa on Mar 22, 2023 10:45:47 GMT
My flawed example was on the song It's My Life by The Animals. I said "the guitar plays a minor third while singer Eric Burdon goes back and forth between major and minor thirds to avoid a clash." You pointed out that Eric alternates between a normal and flatted fifth. I don't recall anything about a fourth higher. Well, that's convenient! I mentioned it in this post - from six years ago! Man, I can't believe this forum has been here that long. Anyway, I guess the song sounded like an Eb tonic and the bass was playing Eb-Ab. According to what I said, you may have thought the bass was playing an Ab chord with the Eb as the P5 instead of an Eb chord with the Ab as a P4. To be certain, I'd have to go back and listen. Overall, the song seems pretty complicated with double flats and blues scales so I'm wary to revisit it. If you want, I'm willing to accept a truce Cheers.
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