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Post by rock on Mar 9, 2022 19:55:20 GMT
Good questions. I'm just trying to keep the conversation going. As Hexspa says, someone else here will straighten us out. We can only hope! For now, this is what I got: I'm not sure this will answer the question but it might help explain the different cut-off frequencies quoted. Here's the link: www.prosoundtraining.com/site/wp-content/uploads/2012/03/VOL36_DEC08_Boundaries-1.pdfYou also ask "Doesn't the wall need a lot of mass? Well we know that if you have a very low mass wall like paper, most LF and Mid-range spectrum will go right through and reflect on HF. I'm sure your walls are not paper One layer of 5/8 drywall on 16" studs reflects most LF plus it resonates (absorbs) a little and transmits some through too. I don't know how much of each but as the mass goes up, the more LF is reflected and the less is transmitted and the lower it resonates. So I'd say yes, the wall needs mass...but how much? Sorry I don't know, but if you're also building for low transmission, you should use at least 2 sheets 5/8 dry wall on each side of the wall. But that's for sound isolation to other rooms. I imagine that kind of mass might also be enough to form a suitable reflective barrier to get down to 20Hz...but even one sheet like in regular construction will probably be sufficient within a reasonable margin...my best guess
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Post by rock on Feb 21, 2022 14:34:50 GMT
Yep, it's just that easy .
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Post by rock on Feb 20, 2022 20:22:06 GMT
OK, just remember, most regular solid state diodes including LEDs need a current limiting resistor to prevent the diode from drawing too much current which will cause instant self-destruction (of the diode, not you ) Here's an LED calculator ledcalculator.net/ to easily get a resistor value that will limit the current to a level that won't destroy your LED. BTW, I have found that some LEDs are way to bright with these calculators so using a larger resistance value than calculated will allow you to get the LED down to a desired brightness. (Using the trial and error method; again, it's a good way to tweak circuits). A bonus to reducing the brightness of an indicator LED, is that with less current draw, you can somewhat extend your battery life
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Post by rock on Feb 19, 2022 16:55:54 GMT
Hi Ethan,
Yeah, I saw that before but I forgot:( Thanks for reminding us!
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Post by rock on Feb 19, 2022 16:39:27 GMT
Oh and Hexspa,
I meant to suggest that regarding your electronic project building: Ethan's Mojo might be a good little project to build. I was thinking about building one for myself. Maybe just a mono channel version to put inline with my interface to use in an analog channel FX loop with my DAW.
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Post by rock on Feb 19, 2022 16:31:59 GMT
Hey Hex,
Wow, talk about going down the rabbit hole! Absolutely a great story but the trial and error method was hardly the take-away (at least for me).
Sorry to sound negative about your contribution but on the contrary, thanks SO MUCH for posting the link!!! I really never knew the story behind the man and his company. So much of his early life and education is relatable to mine even though he's probably 20 years older! I never owned any Oberheim products but a bandmate/roommate around 1980 owned a 4-Voice which I played quite a bit. The very cool thing about it was not only the polyphony but the ability to play four DIFFERENT voices together! One of the more subtle thing I liked to do was to set it up for a horn ensemble patch by tweaking filters and envelopes of each of the four voices to get a texture that even most later (if not all at the time) poly-synths could not yet get!
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Post by rock on Feb 19, 2022 4:17:37 GMT
In short, you need area, volume and coverage to make a difference. That package size 6" x 6" x 16.5" is smaller than a pillow. If you had 50 to 100 of them it would do something but you would be much better off following Ethan's suggestions for corner bass traps and RFZ absorbers placed strategically.
The idea of using bales of fiberglass is the cheapest mostly because there is no labor in manufacturing purpose built panels and installing them on walls ceilings etc. The fiberglass in bales is compressed and if allowed to expand after unpackaged and installed in traps and soffits etc. will probably be more effective and cover a greater area and volume.
I'm sure someone might possibly find shortcuts to acoustic treatments but the results of well designed applications will certainly be superior.
Please search this forum (and others) and read about other member's acoustic treatment situations. You might find that the answers are generally are very similar and basically the same: Coverage, volume and placement.
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Post by rock on Feb 5, 2022 19:40:08 GMT
And then there's Harbor Freight! Several years ago, my son was interested in goofing around with something involving electricity and I got him a cheap (maybe $2 or $3) meter from Harbor Freight. He left it behind when moved out and I just found it and replaced the battery and it seems it's probably all you need...for now anyway. So I looked at The HF website and they have that one for $8 BUT.. the one for $22 is LADEN with features!: www.harborfreight.com/11-function-digital-multimeter-with-audible-continuity-61593.htmlSo I was going to say if you get that $8 one you can "dip your toe in" and see how it goes BUT NOW, I'm saying "splurge" on that HF meter for $22 and you'll probably be good for the foreseeable future. And if you don't like it or it's DOA out of the box you can just bring it back. Keep us posted on your preamp. Right now I'm working on an "Inline Mic Booster" kinda like a "Cloudlifter" if you've seen or heard of them. It's super simple. I'm just waiting for parts from www.taydaelectronics.com/ My son found this site when he was on a pedal building kick (he must have built 2 dozen or so different pedals) So check out Tayda for super low prices and cheap shipping on parts!
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Post by rock on Feb 4, 2022 19:27:55 GMT
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Post by rock on Jan 23, 2022 19:08:06 GMT
Thanks for posting your graphs. They actually look pretty good considering they are pretty much within a 10dB range. That'a what we here usually consider as good as you can practically get.
I overlooked the fact your speakers are flush mounted and if your ceiling reflects to an area behind the listening position, the idea is that you will not hear the early reflections off the ceiling. With the extreme width, the same idea that there will be minimal influence from reflections, if any, from the side walls. That being said, it's my inclination to try an absorbent cloud and also, check the reflection angles/paths from speaker-wall-LP for both speakers with both walls (4 paths). Depending, it might not be a bad idea for RFZ absorbers on side walls too if you don't have them already.
In going over your graphs, I see they line up pretty closely with the room mode calculations. This means if you want to smooth out your SPL further, you just need more broadband absorption all over.
What your QRD is doing may be showing up as fairly regular dips and peaks in the mids and highs. Who knows, maybe it's one of those times where "If Some is Good, More is Better" does not apply? Sorry, IDK
And then there's Sonarworks room correction. I have never used/tried it but it might be a solution.
Finally, I probably should have mentioned this first: How do mixes translate? It may be counterintuitive but it might be worth a try. I hope you find something that works, let us know how it goes!
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Post by rock on Jan 22, 2022 15:43:52 GMT
About your cloud: You know it's primary purpose is for early reflections off the ceiling but also can help the floor to ceiling room modes with increased thickness.
Because of the large width of your room, you may need two; one for each side/speaker. For the reflections, each needs to be centered around the point on the ceiling were a "line of sight" from the LP to each speaker is located on the ceiling. Increase the area/size of the cloud as the distance increases due to the nature of how sound waves "grow" in width as distance increases...like waves in a pond only in 3D it's more like a cone.
If you find you have large enough clouds on each side but end up with a "bare area" overhead, you might decide to put up a third cloud in the middle to make an almost continuous cloud... or just make one big one! This will also help with LF control of room modes.
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Post by rock on Jan 22, 2022 15:13:28 GMT
So as is often the case in the low end, you have room mode SPL and most likely modal ringing issues too. If you're using REW, the "waterfall" display will show you modal ringing expressed in time (ms). For the low end, limit the test range to 300 Hz with no smoothing. You see your Schroeder f is pretty low at 127Hz. amcoustics.com/tools/amroc?l=29&w=15&h=12&ft=true&r60=0.6 due the the size of your room. Your 2K and 8K issues are generally reflection issues. OK to use smoothing for Mid/Hi tests. Did you try measurements at different listening positions? You may/should notice some differences. More absorption can help both Low and Hi but you'll generally need a significant amount to make a difference at least in the low end. The hi end might be easier with targeted RFZ panels and LP/ speaker adjustment etc. These are general ideas, maybe more experienced members can help with finer details. If you have not seen this yet, Hexspa has a series www.youtube.com/watch?v=AQ3fbAjL6SI "How To Set Up A Room". It may help you get the best out of what you've got.
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Post by rock on Jan 21, 2022 13:58:46 GMT
Yeah, taking REW measurements will give you a better idea of what you're dealing with. Take before and during to confirm any changes you make are working for you.
You describe the cloud made of 3/4" plywood with pink on top. To me, that sounds like the entire bottom is reflective plywood??? If I understand correctly, reflection is exactly what you DON'T want a cloud to do. So yeah, replacing (or redesigning) it with an absorbent cloud should help.
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Post by rock on Jan 3, 2022 14:49:49 GMT
Oh, anti-flanking, OK. But you'll still have the direct SPL on the ceiling/floor above. It really depends on how much attenuation you want. One thing I mentioned that you can do is to increase the mass of the bottom of the subfloor above you with drywall. If in doubt of structural status of your building, it's a good idea to hire an engineer to give an OK to adding mass, 2 layers is pretty heavy! (Details in Rod's book)
About the bass traps: With 100% absorption on the walls and ceiling, it could possibly be enough to get away without bass traps. Acoustic testing can give you the answer but not until you're farther along but you of course will be able to add them later. The deeper/thicker the wall Rockboard, the lower the frequency of absorption. Thin foil, plastic, paper etc. does also enhance LF absorption at the expense of some mid & hi freq reflection. Strategic placement/use of plastic etc, so sound source is not reflected back the the listening position is how bass traps are generally located. You might be able to do the same by locating plastic etc. as such. You could do this by trial and error/testing before you install your final decorative fabric.
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Post by rock on Jan 2, 2022 19:34:11 GMT
You wrote: "I can add more flanking, to ceiling etc."
I think maybe you meant "insulation" i.e. fiberglass etc. not flanking... You want LESS or ZERO flanking. Flanking is the conduction of sound vibrations in building materials that "goes around" a well built massive wall which minimizes or negates it by allowing the vibrations to enter the intended isolated room or area via another path. Flanking = Bad.
For the foundation wall, you'll have less to little sound transmission to the upstairs through the concrete BUT, you want a good seal of any space (compressed mineral wool, dry wall, caulk) along the joint between the foundation wall and the floor/wall above.
Sure, If you have a moisture problem seems like dricore is a choice (sorry, I don't have any experience/advice with that problem) but I doubt that it will influence the acoustics one way or the other. There is a thought that a reflective floor in an otherwise anechoic room gives the occupants a kind of spatial orientation by hearing footsteps etc. The other idea is that with total bandwidth ceiling absorption (excellent choice!) and partial bandwidth (hi mid and hi freqs only) as with carpet, that there is an imbalance in frequency spectrum of absorption and ringing etc. (I read about this from F. Alton Everest). If you do want to put something soft on the floor, a rug that is easily put down and moved is a good choice.
Regarding Corner Basstraps: Constuction wise, it should be as easy as framing across the corner and filling with insulation. Whether you want to or can give up the floor space is the only real problem I can figure.
Good Luck! Keep us posted!
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