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Post by Hexspa on Mar 16, 2023 8:01:00 GMT
Sounds like fun enjoy
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Post by Hexspa on Mar 16, 2023 7:58:27 GMT
Hex, you have been a terrific resource in this forum. And I'm still grateful you caught the error in my music theory video, where I confused a flat 5 for a minor 3. Haha I don't remember that exact one. The one that comes to mind is where you decided to write the song a perfect fourth higher key signature because "bass players rarely pedal on I-IV" It was unusual, to be fair. heh
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Post by Hexspa on Mar 15, 2023 10:46:42 GMT
I do not know. Maybe someone else will help.
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Post by Hexspa on Mar 15, 2023 10:43:45 GMT
I'm finding this tread interesting. When I first joined this site, I had a similar question asking if insulation in a closet would affect the acoustics in the room on the other side of the wall or closed closet door. It seems obvious now but it didn't before. Thanks to Ethan, his forum and all the other contributors, I think I now have a pretty good basic idea of what's going on with sound in "small" rooms. (seems to me, priorities seem to change in "medium" and "large" rooms so I'll have to leave that for another day...most of us don't have those size rooms anyway. But now that I think about it, stano's room is on the big side for a "Small Room" and may be entering the "Medium Room" territory. IDK) So, the OP, stanodx5, asks: "Can I use room boundaries as a bass trap?" Well, the answer is no. A solid, rigid, reflective room boundary will not absorb and reduce room modes (to any significant degree if at all). One suggestion is that if the OP wants or needs low freq bass trapping on the rear wall, fill the space with insulation (2,5m is pretty deep so that would be a very effective bass trap). The fill need only be low density fiberglass since the space is so deep. Let's use the idea of 1/4 wave length as theory of the depth to frequency relationship even though actual acoustic measurements may give us even better results. We can calculate freq of 2,5m quarter wavelength to be 34.4 HZ. So if you build a wood stud wall, (or steel stud for fire safety) and fill the 2,5m space behind it, then cover the stud wall with acoustically transparent material, there you go! Now, in addition, Ethan has mentioned the rear wall being a good candidate for diffusion too. Ethan builds combination absorber/diffusors. I think the idea is that the low freqs go "through" the diffusor into the bass trap. So the question is "What are the properties of the diffusor material that will work for this purpose?" If you are going to build DIY diffusors, hopefully Ethan can share or suggest a material for this purpose... if of course it's not proprietary info. (sorry, Ethan may have mentioned this already in a post but IDK or just forgot:( "Just one more thing..." (no this is not a Columbo episode:) I notice the dimensions before and after are both well outside of the "Bolt-area" amcoustics.com/tools/amroc?l=953&w=730&h=350&r60=0.6 but even with that, the node distribution looks pretty good and the size of your room pushes the fundamental mode frequencies quite low. The ceiling/floor is, as usual, the highest first node (47Hz) and the idea of a well treated fully transparent ceiling trap is also as usual a good idea too. Ethan and others have noted that, depending on building material, walls can be about 5% more distant acoustically due to their absorptive properties. Often you'll see measurements which reflect this i.e. an 8' ceiling but ringing below 70Hz (or whatever it is). Additionally, the bass traps you add will contribute further to this. Please allow me to take this time to thank Ethan for creating a hospitable environment here - as much as I tried to burn it down . I've been exploring a few other forms and, let me say, it can be tough out there. Thanks, Ethan!
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Post by Hexspa on Mar 15, 2023 10:40:30 GMT
I think the quarter wavelength idea is more theory than practice. I mean, if 2-inch rigid fiberglass measures as fully absorbing 400 Hz, then there's your answer. Of course, we know that spacing the fiberglass off the wall absorbs even better and to a lower frequency. And 1/4 wavelength spacing puts the fiberglass where wave velocity is maximum. Hmm, that's interesting. Right, I looked at the absorption coefficients and it's true that materials less than 1/4 wavelength have ratings of 1.0 for a given frequency. My guess is that this is due to the sound not arriving completely perpendicular to the absorber i.e. some comes in from an angle, some from the side, and some possibly goes "through" the absorber and bounces back and becomes totally absorbed. On one hand, acoustics can be dead simple. On the other hand, pandora's box.
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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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