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Post by Hexspa on Mar 15, 2023 10:37:54 GMT
Yeah, 12" fluffy is fine. 12" safe n sound is ideal as is 24" fluffy in terms of how thick you can go with each material before adding reflective qualities. If your SnS panels aren't in areas that need to absorb high frequencies, you can use a little spray glue and put some paper on the front of them for better bass absorption.
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Post by Hexspa on Mar 10, 2023 3:15:58 GMT
^Really a brilliant article. It's Ethan's writings that's saved me hundreds of thousands of dollars (in debt) by convincing me a little insulation goes a long way. The lucidity of these writings maintains their value even a decade after he published them; even if their message is lost on many. Reviewing it, the device for identifying SBIR peaks and nulls lines up with my most recent learnings. Genelec also emphasizes the first 1/4 wavelength but they don't go into the harmonic progression of further peaks and nulls. Also, I've never seen a good explanation of LBIR anywhere else.
I have a question. If 2" (5cm) rigid insulation fully absorbs 400Hz, why is that? 1/4 wavelength of 400Hz is 8.44" (21.44cm) and I heard that an absorber needs to be 1/4 wavelength to *fully* absorb a frequency. I understand that partial absorption is possible in additional to full absorption of various frequencies and that this is related to absorber thickness. What I'm unclear about is whether an absorber needs to be 1/4 wavelength thick to fully absorb a given frequency.
Thanks.
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Post by Hexspa on Feb 18, 2023 16:26:55 GMT
You should have a solid, centered phantom image and ideally the speakers 'disappear'. You want to know that left is left and right is right but not have your ear drawn to the speaker or subwoofer. All you want to hear is music. Make sure your speakers are both the same volume, you can test with filtered pink noise and have spectrally balanced reflections. You can read more about that here: www.hifizine.com/2011/12/listening-room-reflections-and-the-energy-time-curve/
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Post by Hexspa on Feb 16, 2023 16:17:36 GMT
Right, I have the HS50 (with sub) and not the newer HS5 and I don't know what they changed. They're decent monitors, fairly low distortion but do suffer from a large and wide midrange peak (+10dB around 850Hz) so consider notching that down some; increasingly narrow directivity above 10kHz (not that most of us hear much there anyway) too. The HS8/0 has good extension so, assuming you get your room squared away, you should be set. They actually received a relatively low score on Audio Science Review (Harman grading) but the best monitors are the ones you can use right now. www.audiosciencereview.com/forum/index.php?threads/yamaha-hs5-powered-monitor-review.10967/
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Post by Hexspa on Feb 15, 2023 22:54:22 GMT
Yeah, the sonarworks one has calibration to 30deg only with sonarworks software and strictly on-axis for without. Again, I don't use a calibrated mic so I'm not sure how important that'll be. What I can say is that I've used the ECM8000 as a voice over mic and it's terrible for that! Granted, I didn't have good positioning and omnis aren't for voice over but I don't think you'll get much use out of a linear omni for recording. Who knows, maybe you will - especially if you have a large or well-dampened space to help you get the most out of it. Here's an ECM for 30 euro: www.thomann.de/gb/behringer_ecm_8000.htm which is a no-excuse buy imo. You can always send it in for calibration later (or at least you could when I was in the market a decade ago). Since you're only getting, what, 4dB out of the calibration, I'd save the money and balance 2kHz and above with a tilt or shelf EQ - but it's up to you, of course. I'd be remiss if I didn't mention a potential upgrade (the salesman in me would be anyway). Neumann and Genelec offer measurement solutions which include measurement mics as add-ons for some of their monitor systems; the KH 80 and 150 and 83x0 and 83x1 respectively. If for some reason you were thinking about upgrading your speakers, you might want to hold off on your measurement mic purchase until you've combed through those options.
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Post by Hexspa on Feb 15, 2023 20:16:59 GMT
Hex, I'm already working with my new client, but you are absolutely not stepping on any toes. I agree that high-end bookshelf size speakers make sense unless it's for a system in a very large space that needs to play very loudly. You da man!
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Post by Hexspa on Feb 15, 2023 20:16:06 GMT
Yes, I was referring to your potential purchase considerations. At least that's what I got from the end of your last post. You definitely want a linear omni measurement mic and not just any mic that'll do omni pattern. I don't think you necessarily need a calibrated one - I don't use any calibration - but it's nice if you can get it. The one I have is the Behringer ECM8000. The trendy one now is the UMIK-1 which is a USB mic. That one is calibrated but supposedly suffers from low-level noise. How much of a problem that is, I don't know. From what I understand they also have a UMIK 2 which I think is XLR.
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Post by Hexspa on Feb 14, 2023 23:45:51 GMT
If I'm not stepping on any toes, some of the coolest stuff I've seen out recently are Genelec Ones 8361A with their adaptive woofer W371A. Either that or two Neumann KH 420 with a pair of their DSP subs. Whatever is left over, just send to me Cheers.
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Post by Hexspa on Feb 14, 2023 23:40:59 GMT
I think Ethan showed that the calibration file mostly affects high frequencies - don't quote me. realtraps.com/art_microphones.htm Any mic will be truthful about the bass which is what matters. The differences are within 4dB above 2kHz unless you use something weird.
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Post by Hexspa on Feb 10, 2023 22:31:33 GMT
Ideally, in another room. If not, along the western wall as far from your listening position as possible. Small desk good.
Speakers close to a wall results in the speaker-boundary interference to be higher in frequency. If you're using a full-range speaker then you want it no more than a half meter from any nearby boundary. In the case of bass-management with a sub then it's either all the way in (a few cm for port function) or 1.1m away from wall. The distance between 0.5m and 1.1m is around 160 to 80Hz. If you pull the full rangers out further then now you have a new bass problem and it's harder to treat. Make sure not to have your speakers equidistant from any two boundaries or these nulls will be even worse. I don't recommend you be moving your speakers around unless you're ok with risking consistent monitoring.
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Post by Hexspa on Feb 8, 2023 23:12:02 GMT
Regarding your room, face the window.
There are two windows, an oversized one on the western wall and a normal sized one on the nothern wall. Which one should I be facing in your opinion?
The northern. The principles behind it is that you want symmetry from your ears forward and maximum distance from your speakers and ears to any boundary. Actually, speaker placement is a little more complex than that. You either want to have your speakers very close or very far from a wall. Anyway, no other orientation meets these criteria.
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Post by Hexspa on Feb 7, 2023 8:19:28 GMT
Let me preface this post by admitting that I did not read your whole post for reasons I go into below. I apologize if I don't answer your question in the following. If it's not in there then please just ask one question at a time. Thank you.
Your post is very detailed. In my opinion, too detailed. Acoustic treatment is easy: your room rings and reflects so you introduce absorption (duh). The geniuses have already digested the complicated stuff to the point where you just grab solutions off the rack.
Listening position: 20, 32 or 45% all axial dimensions. Perform measurements to confirm best performance. Balance that with practicality.
Speakers: equilateral triangle, the closer to your ears, the more accurate the sound (min. 0.5m)
Subwoofer: do a crawl or start between 1/4 wavelength and corner of front wall and apply same caveats as listening position. More subwoofers helps bass.
Absorber functions: early reflections, modal ringing, and speaker-boundary interference. (I just added this for clarity as it's repeated in the next section).
Absorption locations: Primarily, early reflections (walls within 10-20 feet that are between you and the speakers) aka RFZ. Secondarily, modal dampening aka 'bass traps'. Corners are simply convenient places to have an air gap and treat two boundaries at once. Other than that, you just treat as much of the wall as will dampen your target resonance to a sufficient degree. Note that speaker-boundary interference can be mitigated with absorption. This happens most strongly at the 1/4 wavelength of a frequency. So, if your speakers are 2' from a wall then you'll get a cancellation of an 8' wavelength. This is separate from FRZ and modal issues. Bear in mind that your speakers are in a 3D space so front, maybe rear, left and right will all be at cancellation points. When placing your speakers, avoid duplicating these distances (yes you might compromise a little symmetry which is necessary anyway for left-right axial mode).
Absorption type: maximum thicknesses per absorber: 6" rigid, 12" safe n sound, 24" fluffy. Technically, density is not related to absorber performance. It is indirectly a property of resistivity (kind of) which, ultimately, contributes to a panel's resistance (resistivity with a given depth). Let's say that the more dense the material, the thinner it will be before it becomes increasingly reflective (not what you want). If a mouse can't grab chunks out of it then it's rigid and needs to be max 6". Maybe 4lb can be 8" but no guarantees.
Bonus points: 1x air gap behind any panel enhances low end at slight cost in lower mids. FRK enhances low end at the expense of higher frequencies.
Method: empty room, place mic at possible listening position and subwoofer at 1/4 wavelength against front wall or front corner. Identify best spots for both (you'll notice response trends). Install stuff in room including RFZ panels and any panels you'll use for recording. Measure again to identify SPL and ringing issues. Place absorption based on ringing frequencies (which correlate to physical dimensions) until you run out of material or space or achieve your targets*. EQ and balance your subs then integrate with mains. Measure to confirm. Listen to make sure everything sounds right. Revisit any previous steps to apply creative or technical tweaks. Done.
*targets: +-10dB spl with a 1dB/oct slope (or +4dB sub bass relative to 1kHz) and 20dB modal decay within 150 ms above 63Hz with a smooth taper in addition to spectrally balanced early reflections - or better.
Resources: How to predict ringing frequencies: calculate modal harmonics (axial mode): F = n1130/2D (imperial) 1125 ft/s F = n345/2D (metric) speed of sound 343m/s @ 20deg Celcius F is frequency n is harmonic (1-4) D is dimension (distance between walls) first harmonic 16ft length F = 1x1130/32 35.3125Hz C#1
Caveat: you can use pressure absorbers but I haven't and don't think they're required for most home audio applications.
Summary: place absorption where there's a problem. Generally, there're a lot of problems (depending who you ask) so you need a lot of absorption. 15-20% of sufficiently thick (1/4 dimension-thick and low-resistance is ideal) is a good start.
Regarding your room, face the window.
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Post by Hexspa on Feb 6, 2023 17:57:04 GMT
Yeah, I've seen 'pix' (haven't seen that abbreviation in awhile) of frameless panels and they look very middle aged. I'm currently recombining my 2" rigid panels into 6" ones. This metal drywall bead is very sharp but it's much stronger than the vinyl stuff I'm using for my safe n sound 12" panels.
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Post by Hexspa on Feb 5, 2023 18:36:58 GMT
Hi, welcome. I'm just now seeing this but will not be at my computer to review it. Maybe someone else will join in or I can check it out another time. Thanks.
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Post by Hexspa on Feb 2, 2023 12:09:58 GMT
Sorry, I've been away for a while. Hex is correct! But add on and put it another way: (cletuschrist wrote:) "Thanks! I was confused about whether the gap had something to do with waves hitting the wall and bouncing back into the insulation, or if it really only matters when the wave energy goes through the insulation once THEN AGAIN after hitting the wall coming back the other way." I'd answer: It's BOTH!. Sound waves bounce off the wall from both going through the absorber first and then back again... and to a lesser degree from any sound waves reflecting off the wall from other angles. Good to have you back. Any war stories?
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