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Post by dwayne on Jun 12, 2019 0:17:21 GMT
My first post here....
I just bought a new place and I’m left with an L-shaped room for recording and mixing...or at least plan to. I’ve started to use REW and the frequency response looks ok, but I have incredible amounts of reverb. So clearly absorption is required. What I’m planning on doing is setting up my RFZ in one leg of the L....and the using REW to tame the reflections further and diffuse if necessary. The length of the section I’m setting up in is 25 feet long down the long wall....typical 8 foot ceiling and 12 feet wide. The short wall is about 12 long before opening up to the other se ruin. I know this shape of room is less than desirable, but does it make sense to create movable panels to create a rectangular room? Am I on the right path as far as absorption and diffusion is concerned?
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Post by Hexspa on Jun 13, 2019 1:48:04 GMT
Helpful if you post pics illustrating your intended layout including listening position, panel thickness, immovable obstacles and features such as windows. Please keep the image under 100KB. You probably won't need diffusion - at least not at first.
Just want to add that much of what you're seeing is not technically 'reverb' as such but 'modal ringing'. Above that, you probably have a buildup of 'early reflections' but not so many or so long or so diffuse to be an actual 'reverb tail'. There's dispute over the use of the terms 'early reflections' and 'reverb tail' by companies such as Lexicon - ironic given their name - but I'm in the camp, along with Ethan, that there's a difference.
I'm all about being pedantic over here so don't screw it up 
Double edit: Gah. The internet is full of atrocities. Why did they title tag that page 'What is "Early Reflections"?' Makes me sick. Hey, Sweetwater - try this on for size:
What are 'Early Reflections'?
PSA: Video coming soon about pan law. Apparently people don't believe that you can pan something left, right, or center without changing the volume. Well, my pink noise, 1kHz sine wave, SPL meter and Sound On Sound article beg to differ. I'm really on a roll. |
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Post by dwayne on Jun 13, 2019 23:20:00 GMT
Here is a rough drawing of the room...dimensions are in inches... Also here are some REW pics of what is happening. I bought some Rockwool Safe and Sound 3" tonight, and put bats roughly in place to see what they would do...not much of an improvement. Thoughts? Ideas? |
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Post by dwayne on Jun 13, 2019 23:20:40 GMT
Here is the waterfall Attachments:
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Post by Hexspa on Jun 14, 2019 2:32:06 GMT
Thanks for posting. Doesn't look too bad but we need to reign in your graph parameters to better diagnose your problems. Please show the following graphs: 1. Full SPL, no smoothing, 20Hz-20kHz, showing a 1-5dB resolution on the Y axis. 2. Full SPL, smoothed, 20Hz-20kHz, showing a 1-5dB resolution on the Y axis. 3. Bass SPL, no smoothing, 20-300Hz, showing a 1-5dB resolution on the Y axis. 4. Waterfall, no smoothing, 20-300Hz, 10dB above any peak, 300ms time domain Z axis, showing an average of about 30dB of decay across the range. 5. Decay, no smoothing, 20-300Hz, showing 150ms decay time (or as close as possible in REW).
BONUS: It'd be great if you can do each of these both with the room relatively empty and then another with treatment. Basically, your graphs are too far zoomed out to be very useful. The bats will definitely make an improvement but you'll need enough of them. Try to make them 4-8" and plan on using over 20, if possible; the more the better. You'll see a marked improvement in decay though much of SPL has to do with positioning. One thing I can tell you is that your 70Hz peak is related to the 8' ceiling - everyone gets that.
You're aiming for +-10dB SPL and 20dB decay within 150ms above 63Hz - or better. Treat your RFZ then keep adding panels until you achieve your result. Remember to optimize your positioning before drilling any holes.
I didn't mention it nor see you say anything but face away from the hall. Your measurements look fine so I'm assuming you're already doing that. Just wanted to make sure.
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Post by dwayne on Jun 14, 2019 3:28:57 GMT
Im set up on the top part of the drawing.....RFZ is in that top section. Listening position is 38% back from front wall |
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Post by dwayne on Jun 14, 2019 3:30:18 GMT
Hope i did the scaling correct |
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Post by Hexspa on Jun 15, 2019 0:56:05 GMT
In your drawing, I was hoping to see where you placed the treatment. Usually, you want to have your side walls somewhat further away which is why I recommended that you have the hall behind you. Like I said before, most things look good. You clearly have a strong resonance at 70Hz which should be due to anything at 16' or 8' - like the ceiling. Placing more treatment there, as in the RFZ, should help. After that you can consider EQ attenuation. The nulling around 52Hz is related to a 5.45' or 16.35' boundary. The one around 58Hz is related to a 4.85' or 14.54' boundary.
Given that you have nearly the entire 50-60Hz range somewhat depressed, it can be a combination of a few factors related to those dimensions and ones in between. You'll definitely want to heavily treat those areas and probably treat your 10' and 20' dimensions slightly less. In this way, you can balance the modal response depending on surface proximity which can cause too much reflective energy, etc. Again, you want about 20dB of decay within 150ms. I can't tell that from your decay graph nor waterfall because in the decay plot, you cropped out the values and I don't remember what they are. You only need to show those about 150ms i.e. you can uncheck the others. You can also uncheck 'fill' so you're just getting the outline of the levels. This makes it easier to read. With the waterfall, you only need to show about 30dB of decay but you're showing 50dB. I want the 'mountains' to 'fade into silence', as it were. The 'silence' being the limits of the graph so I can see on the time domain how far out you are. But ya, none of this really matters until I know how many panels and where you've placed them. I also don't know your speaker system and if it includes a sub or driver size. |
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Post by Hexspa on May 10, 2020 3:33:34 GMT
Dwayne, I know this post is old but I'm making a video on how to analyze a room and want to use yours as an example of a common 70Hz mode. Let me know if that's ok.
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